Sys::Guestfs(3) User Contributed Perl Documentation Sys::Guestfs(3)NAMESys::Guestfs - Perl bindings for libguestfs
SYNOPSIS
use Sys::Guestfs;
my $g = Sys::Guestfs->new ();
$g->add_drive_opts ('guest.img', format => 'raw');
$g->launch ();
$g->mount_options ('', '/dev/sda1', '/');
$g->touch ('/hello');
$g->shutdown ();
$g->close ();
DESCRIPTION
The "Sys::Guestfs" module provides a Perl XS binding to the libguestfs
API for examining and modifying virtual machine disk images.
Amongst the things this is good for: making batch configuration changes
to guests, getting disk used/free statistics (see also: virt-df),
migrating between virtualization systems (see also: virt-p2v),
performing partial backups, performing partial guest clones, cloning
guests and changing registry/UUID/hostname info, and much else besides.
Libguestfs uses Linux kernel and qemu code, and can access any type of
guest filesystem that Linux and qemu can, including but not limited to:
ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition
schemes, qcow, qcow2, vmdk.
Libguestfs provides ways to enumerate guest storage (eg. partitions,
LVs, what filesystem is in each LV, etc.). It can also run commands in
the context of the guest. Also you can access filesystems over FUSE.
See also Sys::Guestfs::Lib(3) for a set of useful library functions for
using libguestfs from Perl, including integration with libvirt.
ERRORS
All errors turn into calls to "croak" (see Carp(3)).
The error string from libguestfs is directly available from $@. Use
the "last_errno" method if you want to get the errno.
METHODS
$g = Sys::Guestfs->new ();
Create a new guestfs handle.
$g->close ();
Explicitly close the guestfs handle.
Note: You should not usually call this function. The handle will
be closed implicitly when its reference count goes to zero (eg.
when it goes out of scope or the program ends). This call is only
required in some exceptional cases, such as where the program may
contain cached references to the handle 'somewhere' and you really
have to have the close happen right away. After calling "close"
the program must not call any method (including "close") on the
handle (but the implicit call to "DESTROY" that happens when the
final reference is cleaned up is OK).
$Sys::Guestfs::EVENT_CLOSE
See "GUESTFS_EVENT_CLOSE" in guestfs(3).
$Sys::Guestfs::EVENT_SUBPROCESS_QUIT
See "GUESTFS_EVENT_SUBPROCESS_QUIT" in guestfs(3).
$Sys::Guestfs::EVENT_LAUNCH_DONE
See "GUESTFS_EVENT_LAUNCH_DONE" in guestfs(3).
$Sys::Guestfs::EVENT_PROGRESS
See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
$Sys::Guestfs::EVENT_APPLIANCE
See "GUESTFS_EVENT_APPLIANCE" in guestfs(3).
$Sys::Guestfs::EVENT_LIBRARY
See "GUESTFS_EVENT_LIBRARY" in guestfs(3).
$Sys::Guestfs::EVENT_TRACE
See "GUESTFS_EVENT_TRACE" in guestfs(3).
$Sys::Guestfs::EVENT_ENTER
See "GUESTFS_EVENT_ENTER" in guestfs(3).
$event_handle = $g->set_event_callback (\&cb, $event_bitmask);
Register "cb" as a callback function for all of the events in
$event_bitmask (one or more "$Sys::Guestfs::EVENT_*" flags
logically or'd together).
This function returns an event handle which can be used to delete
the callback using "delete_event_callback".
The callback function receives 4 parameters:
&cb ($event, $event_handle, $buf, $array)
$event
The event which happened (equal to one of
"$Sys::Guestfs::EVENT_*").
$event_handle
The event handle.
$buf
For some event types, this is a message buffer (ie. a string).
$array
For some event types (notably progress events), this is an
array of integers.
You should carefully read the documentation for
"guestfs_set_event_callback" in guestfs(3) before using this
function.
$g->delete_event_callback ($event_handle);
This removes the callback which was previously registered using
"set_event_callback".
$errnum = $g->last_errno ();
This returns the last error number (errno) that happened on the
handle $g.
If successful, an errno integer not equal to zero is returned.
If no error number is available, this returns 0. See
"guestfs_last_errno" in guestfs(3) for more details of why this can
happen.
You can use the standard Perl module Errno(3) to compare the
numeric error returned from this call with symbolic errnos:
$g->mkdir ("/foo");
if ($g->last_errno() == Errno::EEXIST()) {
# mkdir failed because the directory exists already.
}
$g->user_cancel ();
Cancel current transfer. This is safe to call from Perl signal
handlers and threads.
$g->add_cdrom ($filename);
This function adds a virtual CD-ROM disk image to the guest.
This is equivalent to the qemu parameter -cdrom filename.
Notes:
· This call checks for the existence of "filename". This stops
you from specifying other types of drive which are supported by
qemu such as "nbd:" and "http:" URLs. To specify those, use
the general "$g->config" call instead.
· If you just want to add an ISO file (often you use this as an
efficient way to transfer large files into the guest), then you
should probably use "$g->add_drive_ro" instead.
This function is deprecated. In new code, use the "add_drive_opts"
call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$nrdisks = $g->add_domain ($dom [, libvirturi => $libvirturi] [,
readonly => $readonly] [, iface => $iface] [, live => $live] [,
allowuuid => $allowuuid] [, readonlydisk => $readonlydisk]);
This function adds the disk(s) attached to the named libvirt domain
"dom". It works by connecting to libvirt, requesting the domain
and domain XML from libvirt, parsing it for disks, and calling
"$g->add_drive_opts" on each one.
The number of disks added is returned. This operation is atomic:
if an error is returned, then no disks are added.
This function does some minimal checks to make sure the libvirt
domain is not running (unless "readonly" is true). In a future
version we will try to acquire the libvirt lock on each disk.
Disks must be accessible locally. This often means that adding
disks from a remote libvirt connection (see
<http://libvirt.org/remote.html>) will fail unless those disks are
accessible via the same device path locally too.
The optional "libvirturi" parameter sets the libvirt URI (see
<http://libvirt.org/uri.html>). If this is not set then we connect
to the default libvirt URI (or one set through an environment
variable, see the libvirt documentation for full details).
The optional "live" flag controls whether this call will try to
connect to a running virtual machine "guestfsd" process if it sees
a suitable <channel> element in the libvirt XML definition. The
default (if the flag is omitted) is never to try. See "ATTACHING
TO RUNNING DAEMONS" in guestfs(3) for more information.
If the "allowuuid" flag is true (default is false) then a UUID may
be passed instead of the domain name. The "dom" string is treated
as a UUID first and looked up, and if that lookup fails then we
treat "dom" as a name as usual.
The optional "readonlydisk" parameter controls what we do for disks
which are marked <readonly/> in the libvirt XML. Possible values
are:
readonlydisk = "error"
If "readonly" is false:
The whole call is aborted with an error if any disk with the
<readonly/> flag is found.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "read"
If "readonly" is false:
Disks with the <readonly/> flag are added read-only. Other
disks are added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "write" (default)
If "readonly" is false:
Disks with the <readonly/> flag are added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "ignore"
If "readonly" is true or false:
Disks with the <readonly/> flag are skipped.
The other optional parameters are passed directly through to
"$g->add_drive_opts".
$g->add_drive ($filename);
This function is the equivalent of calling "$g->add_drive_opts"
with no optional parameters, so the disk is added writable, with
the format being detected automatically.
Automatic detection of the format opens you up to a potential
security hole when dealing with untrusted raw-format images. See
CVE-2010-3851 and RHBZ#642934. Specifying the format closes this
security hole. Therefore you should think about replacing calls to
this function with calls to "$g->add_drive_opts", and specifying
the format.
$g->add_drive_opts ($filename [, readonly => $readonly] [, format =>
$format] [, iface => $iface] [, name => $name]);
This function adds a disk image called "filename" to the handle.
"filename" may be a regular host file or a host device.
The first time you call this function, the disk appears as
"/dev/sda", the second time as "/dev/sdb", and so on.
You don't necessarily need to be root when using libguestfs.
However you obviously do need sufficient permissions to access the
filename for whatever operations you want to perform (ie. read
access if you just want to read the image or write access if you
want to modify the image).
This call checks that "filename" exists.
"filename" may be the special string "/dev/null". See "NULL DISKS"
in guestfs(3).
The optional arguments are:
"readonly"
If true then the image is treated as read-only. Writes are
still allowed, but they are stored in a temporary snapshot
overlay which is discarded at the end. The disk that you add
is not modified.
"format"
This forces the image format. If you omit this (or use
"$g->add_drive" or "$g->add_drive_ro") then the format is
automatically detected. Possible formats include "raw" and
"qcow2".
Automatic detection of the format opens you up to a potential
security hole when dealing with untrusted raw-format images.
See CVE-2010-3851 and RHBZ#642934. Specifying the format
closes this security hole.
"iface"
This rarely-used option lets you emulate the behaviour of the
deprecated "$g->add_drive_with_if" call (q.v.)
"name"
The name the drive had in the original guest, e.g. "/dev/sdb".
This is used as a hint to the guest inspection process if it is
available.
$g->add_drive_ro ($filename);
This function is the equivalent of calling "$g->add_drive_opts"
with the optional parameter "GUESTFS_ADD_DRIVE_OPTS_READONLY" set
to 1, so the disk is added read-only, with the format being
detected automatically.
$g->add_drive_ro_with_if ($filename, $iface);
This is the same as "$g->add_drive_ro" but it allows you to specify
the QEMU interface emulation to use at run time.
This function is deprecated. In new code, use the "add_drive_opts"
call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->add_drive_with_if ($filename, $iface);
This is the same as "$g->add_drive" but it allows you to specify
the QEMU interface emulation to use at run time.
This function is deprecated. In new code, use the "add_drive_opts"
call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->aug_clear ($augpath);
Set the value associated with "path" to "NULL". This is the same
as the augtool(1) "clear" command.
$g->aug_close ();
Close the current Augeas handle and free up any resources used by
it. After calling this, you have to call "$g->aug_init" again
before you can use any other Augeas functions.
%nrnodescreated = $g->aug_defnode ($name, $expr, $val);
Defines a variable "name" whose value is the result of evaluating
"expr".
If "expr" evaluates to an empty nodeset, a node is created,
equivalent to calling "$g->aug_set" "expr", "value". "name" will
be the nodeset containing that single node.
On success this returns a pair containing the number of nodes in
the nodeset, and a boolean flag if a node was created.
$nrnodes = $g->aug_defvar ($name, $expr);
Defines an Augeas variable "name" whose value is the result of
evaluating "expr". If "expr" is NULL, then "name" is undefined.
On success this returns the number of nodes in "expr", or 0 if
"expr" evaluates to something which is not a nodeset.
$val = $g->aug_get ($augpath);
Look up the value associated with "path". If "path" matches
exactly one node, the "value" is returned.
$g->aug_init ($root, $flags);
Create a new Augeas handle for editing configuration files. If
there was any previous Augeas handle associated with this guestfs
session, then it is closed.
You must call this before using any other "$g->aug_*" commands.
"root" is the filesystem root. "root" must not be NULL, use "/"
instead.
The flags are the same as the flags defined in <augeas.h>, the
logical or of the following integers:
"AUG_SAVE_BACKUP" = 1
Keep the original file with a ".augsave" extension.
"AUG_SAVE_NEWFILE" = 2
Save changes into a file with extension ".augnew", and do not
overwrite original. Overrides "AUG_SAVE_BACKUP".
"AUG_TYPE_CHECK" = 4
Typecheck lenses.
This option is only useful when debugging Augeas lenses. Use
of this option may require additional memory for the libguestfs
appliance. You may need to set the "LIBGUESTFS_MEMSIZE"
environment variable or call "$g->set_memsize".
"AUG_NO_STDINC" = 8
Do not use standard load path for modules.
"AUG_SAVE_NOOP" = 16
Make save a no-op, just record what would have been changed.
"AUG_NO_LOAD" = 32
Do not load the tree in "$g->aug_init".
To close the handle, you can call "$g->aug_close".
To find out more about Augeas, see <http://augeas.net/>.
$g->aug_insert ($augpath, $label, $before);
Create a new sibling "label" for "path", inserting it into the tree
before or after "path" (depending on the boolean flag "before").
"path" must match exactly one existing node in the tree, and
"label" must be a label, ie. not contain "/", "*" or end with a
bracketed index "[N]".
$g->aug_load ();
Load files into the tree.
See "aug_load" in the Augeas documentation for the full gory
details.
@matches = $g->aug_ls ($augpath);
This is just a shortcut for listing "$g->aug_match" "path/*" and
sorting the resulting nodes into alphabetical order.
@matches = $g->aug_match ($augpath);
Returns a list of paths which match the path expression "path".
The returned paths are sufficiently qualified so that they match
exactly one node in the current tree.
$g->aug_mv ($src, $dest);
Move the node "src" to "dest". "src" must match exactly one node.
"dest" is overwritten if it exists.
$nrnodes = $g->aug_rm ($augpath);
Remove "path" and all of its children.
On success this returns the number of entries which were removed.
$g->aug_save ();
This writes all pending changes to disk.
The flags which were passed to "$g->aug_init" affect exactly how
files are saved.
$g->aug_set ($augpath, $val);
Set the value associated with "path" to "val".
In the Augeas API, it is possible to clear a node by setting the
value to NULL. Due to an oversight in the libguestfs API you
cannot do that with this call. Instead you must use the
"$g->aug_clear" call.
$g->available (\@groups);
This command is used to check the availability of some groups of
functionality in the appliance, which not all builds of the
libguestfs appliance will be able to provide.
The libguestfs groups, and the functions that those groups
correspond to, are listed in "AVAILABILITY" in guestfs(3). You can
also fetch this list at runtime by calling
"$g->available_all_groups".
The argument "groups" is a list of group names, eg: "["inotify",
"augeas"]" would check for the availability of the Linux inotify
functions and Augeas (configuration file editing) functions.
The command returns no error if all requested groups are available.
It fails with an error if one or more of the requested groups is
unavailable in the appliance.
If an unknown group name is included in the list of groups then an
error is always returned.
Notes:
· You must call "$g->launch" before calling this function.
The reason is because we don't know what groups are supported
by the appliance/daemon until it is running and can be queried.
· If a group of functions is available, this does not necessarily
mean that they will work. You still have to check for errors
when calling individual API functions even if they are
available.
· It is usually the job of distro packagers to build complete
functionality into the libguestfs appliance. Upstream
libguestfs, if built from source with all requirements
satisfied, will support everything.
· This call was added in version 1.0.80. In previous versions of
libguestfs all you could do would be to speculatively execute a
command to find out if the daemon implemented it. See also
"$g->version".
@groups = $g->available_all_groups ();
This command returns a list of all optional groups that this daemon
knows about. Note this returns both supported and unsupported
groups. To find out which ones the daemon can actually support you
have to call "$g->available" on each member of the returned list.
See also "$g->available" and "AVAILABILITY" in guestfs(3).
$g->base64_in ($base64file, $filename);
This command uploads base64-encoded data from "base64file" to
"filename".
$g->base64_out ($filename, $base64file);
This command downloads the contents of "filename", writing it out
to local file "base64file" encoded as base64.
%info = $g->blkid ($device);
This command returns block device attributes for "device". The
following fields are usually present in the returned hash. Other
fields may also be present.
"UUID"
The uuid of this device.
"LABEL"
The label of this device.
"VERSION"
The version of blkid command.
"TYPE"
The filesystem type or RAID of this device.
"USAGE"
The usage of this device, for example "filesystem" or "raid".
$g->blockdev_flushbufs ($device);
This tells the kernel to flush internal buffers associated with
"device".
This uses the blockdev(8) command.
$blocksize = $g->blockdev_getbsz ($device);
This returns the block size of a device.
(Note this is different from both size in blocks and filesystem
block size).
This uses the blockdev(8) command.
$ro = $g->blockdev_getro ($device);
Returns a boolean indicating if the block device is read-only (true
if read-only, false if not).
This uses the blockdev(8) command.
$sizeinbytes = $g->blockdev_getsize64 ($device);
This returns the size of the device in bytes.
See also "$g->blockdev_getsz".
This uses the blockdev(8) command.
$sectorsize = $g->blockdev_getss ($device);
This returns the size of sectors on a block device. Usually 512,
but can be larger for modern devices.
(Note, this is not the size in sectors, use "$g->blockdev_getsz"
for that).
This uses the blockdev(8) command.
$sizeinsectors = $g->blockdev_getsz ($device);
This returns the size of the device in units of 512-byte sectors
(even if the sectorsize isn't 512 bytes ... weird).
See also "$g->blockdev_getss" for the real sector size of the
device, and "$g->blockdev_getsize64" for the more useful size in
bytes.
This uses the blockdev(8) command.
$g->blockdev_rereadpt ($device);
Reread the partition table on "device".
This uses the blockdev(8) command.
$g->blockdev_setbsz ($device, $blocksize);
This sets the block size of a device.
(Note this is different from both size in blocks and filesystem
block size).
This uses the blockdev(8) command.
$g->blockdev_setro ($device);
Sets the block device named "device" to read-only.
This uses the blockdev(8) command.
$g->blockdev_setrw ($device);
Sets the block device named "device" to read-write.
This uses the blockdev(8) command.
$g->btrfs_filesystem_resize ($mountpoint [, size => $size]);
This command resizes a btrfs filesystem.
Note that unlike other resize calls, the filesystem has to be
mounted and the parameter is the mountpoint not the device (this is
a requirement of btrfs itself).
The optional parameters are:
"size"
The new size (in bytes) of the filesystem. If omitted, the
filesystem is resized to the maximum size.
See also btrfs(8).
$rpath = $g->case_sensitive_path ($path);
This can be used to resolve case insensitive paths on a filesystem
which is case sensitive. The use case is to resolve paths which
you have read from Windows configuration files or the Windows
Registry, to the true path.
The command handles a peculiarity of the Linux ntfs-3g filesystem
driver (and probably others), which is that although the underlying
filesystem is case-insensitive, the driver exports the filesystem
to Linux as case-sensitive.
One consequence of this is that special directories such as
"c:\windows" may appear as "/WINDOWS" or "/windows" (or other
things) depending on the precise details of how they were created.
In Windows itself this would not be a problem.
Bug or feature? You decide:
http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1
<http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1>
This function resolves the true case of each element in the path
and returns the case-sensitive path.
Thus "$g->case_sensitive_path" ("/Windows/System32") might return
"/WINDOWS/system32" (the exact return value would depend on details
of how the directories were originally created under Windows).
Note: This function does not handle drive names, backslashes etc.
See also "$g->realpath".
$content = $g->cat ($path);
Return the contents of the file named "path".
Note that this function cannot correctly handle binary files
(specifically, files containing "\0" character which is treated as
end of string). For those you need to use the "$g->read_file" or
"$g->download" functions which have a more complex interface.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$checksum = $g->checksum ($csumtype, $path);
This call computes the MD5, SHAx or CRC checksum of the file named
"path".
The type of checksum to compute is given by the "csumtype"
parameter which must have one of the following values:
"crc"
Compute the cyclic redundancy check (CRC) specified by POSIX
for the "cksum" command.
"md5"
Compute the MD5 hash (using the "md5sum" program).
"sha1"
Compute the SHA1 hash (using the "sha1sum" program).
"sha224"
Compute the SHA224 hash (using the "sha224sum" program).
"sha256"
Compute the SHA256 hash (using the "sha256sum" program).
"sha384"
Compute the SHA384 hash (using the "sha384sum" program).
"sha512"
Compute the SHA512 hash (using the "sha512sum" program).
The checksum is returned as a printable string.
To get the checksum for a device, use "$g->checksum_device".
To get the checksums for many files, use "$g->checksums_out".
$checksum = $g->checksum_device ($csumtype, $device);
This call computes the MD5, SHAx or CRC checksum of the contents of
the device named "device". For the types of checksums supported
see the "$g->checksum" command.
$g->checksums_out ($csumtype, $directory, $sumsfile);
This command computes the checksums of all regular files in
"directory" and then emits a list of those checksums to the local
output file "sumsfile".
This can be used for verifying the integrity of a virtual machine.
However to be properly secure you should pay attention to the
output of the checksum command (it uses the ones from GNU
coreutils). In particular when the filename is not printable,
coreutils uses a special backslash syntax. For more information,
see the GNU coreutils info file.
$g->chmod ($mode, $path);
Change the mode (permissions) of "path" to "mode". Only numeric
modes are supported.
Note: When using this command from guestfish, "mode" by default
would be decimal, unless you prefix it with 0 to get octal, ie. use
0700 not 700.
The mode actually set is affected by the umask.
$g->chown ($owner, $group, $path);
Change the file owner to "owner" and group to "group".
Only numeric uid and gid are supported. If you want to use names,
you will need to locate and parse the password file yourself
(Augeas support makes this relatively easy).
$output = $g->command (\@arguments);
This call runs a command from the guest filesystem. The filesystem
must be mounted, and must contain a compatible operating system
(ie. something Linux, with the same or compatible processor
architecture).
The single parameter is an argv-style list of arguments. The first
element is the name of the program to run. Subsequent elements are
parameters. The list must be non-empty (ie. must contain a program
name). Note that the command runs directly, and is not invoked via
the shell (see "$g->sh").
The return value is anything printed to stdout by the command.
If the command returns a non-zero exit status, then this function
returns an error message. The error message string is the content
of stderr from the command.
The $PATH environment variable will contain at least "/usr/bin" and
"/bin". If you require a program from another location, you should
provide the full path in the first parameter.
Shared libraries and data files required by the program must be
available on filesystems which are mounted in the correct places.
It is the caller's responsibility to ensure all filesystems that
are needed are mounted at the right locations.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->command_lines (\@arguments);
This is the same as "$g->command", but splits the result into a
list of lines.
See also: "$g->sh_lines"
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->compress_device_out ($ctype, $device, $zdevice [, level =>
$level]);
This command compresses "device" and writes it out to the local
file "zdevice".
The "ctype" and optional "level" parameters have the same meaning
as in "$g->compress_out".
$g->compress_out ($ctype, $file, $zfile [, level => $level]);
This command compresses "file" and writes it out to the local file
"zfile".
The compression program used is controlled by the "ctype"
parameter. Currently this includes: "compress", "gzip", "bzip2",
"xz" or "lzop". Some compression types may not be supported by
particular builds of libguestfs, in which case you will get an
error containing the substring "not supported".
The optional "level" parameter controls compression level. The
meaning and default for this parameter depends on the compression
program being used.
$g->config ($qemuparam, $qemuvalue);
This can be used to add arbitrary qemu command line parameters of
the form -param value. Actually it's not quite arbitrary - we
prevent you from setting some parameters which would interfere with
parameters that we use.
The first character of "param" string must be a "-" (dash).
"value" can be NULL.
$g->copy_device_to_device ($src, $dest [, srcoffset => $srcoffset] [,
destoffset => $destoffset] [, size => $size]);
The four calls "$g->copy_device_to_device",
"$g->copy_device_to_file", "$g->copy_file_to_device", and
"$g->copy_file_to_file" let you copy from a source (device|file) to
a destination (device|file).
Partial copies can be made since you can specify optionally the
source offset, destination offset and size to copy. These values
are all specified in bytes. If not given, the offsets both default
to zero, and the size defaults to copying as much as possible until
we hit the end of the source.
The source and destination may be the same object. However
overlapping regions may not be copied correctly.
If the destination is a file, it is created if required. If the
destination file is not large enough, it is extended.
$g->copy_device_to_file ($src, $dest [, srcoffset => $srcoffset] [,
destoffset => $destoffset] [, size => $size]);
See "$g->copy_device_to_device" for a general overview of this
call.
$g->copy_file_to_device ($src, $dest [, srcoffset => $srcoffset] [,
destoffset => $destoffset] [, size => $size]);
See "$g->copy_device_to_device" for a general overview of this
call.
$g->copy_file_to_file ($src, $dest [, srcoffset => $srcoffset] [,
destoffset => $destoffset] [, size => $size]);
See "$g->copy_device_to_device" for a general overview of this
call.
This is not the function you want for copying files. This is for
copying blocks within existing files. See "$g->cp", "$g->cp_a" and
"$g->mv" for general file copying and moving functions.
$g->copy_size ($src, $dest, $size);
This command copies exactly "size" bytes from one source device or
file "src" to another destination device or file "dest".
Note this will fail if the source is too short or if the
destination is not large enough.
This function is deprecated. In new code, use the
"copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->cp ($src, $dest);
This copies a file from "src" to "dest" where "dest" is either a
destination filename or destination directory.
$g->cp_a ($src, $dest);
This copies a file or directory from "src" to "dest" recursively
using the "cp -a" command.
$g->dd ($src, $dest);
This command copies from one source device or file "src" to another
destination device or file "dest". Normally you would use this to
copy to or from a device or partition, for example to duplicate a
filesystem.
If the destination is a device, it must be as large or larger than
the source file or device, otherwise the copy will fail. This
command cannot do partial copies (see "$g->copy_device_to_device").
This function is deprecated. In new code, use the
"copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$index = $g->device_index ($device);
This function takes a device name (eg. "/dev/sdb") and returns the
index of the device in the list of devices.
Index numbers start from 0. The named device must exist, for
example as a string returned from "$g->list_devices".
See also "$g->list_devices", "$g->part_to_dev".
$output = $g->df ();
This command runs the "df" command to report disk space used.
This command is mostly useful for interactive sessions. It is not
intended that you try to parse the output string. Use
"$g->statvfs" from programs.
$output = $g->df_h ();
This command runs the "df -h" command to report disk space used in
human-readable format.
This command is mostly useful for interactive sessions. It is not
intended that you try to parse the output string. Use
"$g->statvfs" from programs.
$kmsgs = $g->dmesg ();
This returns the kernel messages ("dmesg" output) from the guest
kernel. This is sometimes useful for extended debugging of
problems.
Another way to get the same information is to enable verbose
messages with "$g->set_verbose" or by setting the environment
variable "LIBGUESTFS_DEBUG=1" before running the program.
$g->download ($remotefilename, $filename);
Download file "remotefilename" and save it as "filename" on the
local machine.
"filename" can also be a named pipe.
See also "$g->upload", "$g->cat".
$g->download_offset ($remotefilename, $filename, $offset, $size);
Download file "remotefilename" and save it as "filename" on the
local machine.
"remotefilename" is read for "size" bytes starting at "offset"
(this region must be within the file or device).
Note that there is no limit on the amount of data that can be
downloaded with this call, unlike with "$g->pread", and this call
always reads the full amount unless an error occurs.
See also "$g->download", "$g->pread".
$g->drop_caches ($whattodrop);
This instructs the guest kernel to drop its page cache, and/or
dentries and inode caches. The parameter "whattodrop" tells the
kernel what precisely to drop, see http://linux-mm.org/Drop_Caches
<http://linux-mm.org/Drop_Caches>
Setting "whattodrop" to 3 should drop everything.
This automatically calls sync(2) before the operation, so that the
maximum guest memory is freed.
$sizekb = $g->du ($path);
This command runs the "du -s" command to estimate file space usage
for "path".
"path" can be a file or a directory. If "path" is a directory then
the estimate includes the contents of the directory and all
subdirectories (recursively).
The result is the estimated size in kilobytes (ie. units of 1024
bytes).
$g->e2fsck ($device [, correct => $correct] [, forceall => $forceall]);
This runs the ext2/ext3 filesystem checker on "device". It can
take the following optional arguments:
"correct"
Automatically repair the file system. This option will cause
e2fsck to automatically fix any filesystem problems that can be
safely fixed without human intervention.
This option may not be specified at the same time as the
"forceall" option.
"forceall"
Assume an answer of 'yes' to all questions; allows e2fsck to be
used non-interactively.
This option may not be specified at the same time as the
"correct" option.
$g->e2fsck_f ($device);
This runs "e2fsck -p -f device", ie. runs the ext2/ext3 filesystem
checker on "device", noninteractively (-p), even if the filesystem
appears to be clean (-f).
This command is only needed because of "$g->resize2fs" (q.v.).
Normally you should use "$g->fsck".
$output = $g->echo_daemon (\@words);
This command concatenates the list of "words" passed with single
spaces between them and returns the resulting string.
You can use this command to test the connection through to the
daemon.
See also "$g->ping_daemon".
@lines = $g->egrep ($regex, $path);
This calls the external "egrep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->egrepi ($regex, $path);
This calls the external "egrep -i" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$equality = $g->equal ($file1, $file2);
This compares the two files "file1" and "file2" and returns true if
their content is exactly equal, or false otherwise.
The external cmp(1) program is used for the comparison.
$existsflag = $g->exists ($path);
This returns "true" if and only if there is a file, directory (or
anything) with the given "path" name.
See also "$g->is_file", "$g->is_dir", "$g->stat".
$g->fallocate ($path, $len);
This command preallocates a file (containing zero bytes) named
"path" of size "len" bytes. If the file exists already, it is
overwritten.
Do not confuse this with the guestfish-specific "alloc" command
which allocates a file in the host and attaches it as a device.
This function is deprecated. In new code, use the "fallocate64"
call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->fallocate64 ($path, $len);
This command preallocates a file (containing zero bytes) named
"path" of size "len" bytes. If the file exists already, it is
overwritten.
Note that this call allocates disk blocks for the file. To create
a sparse file use "$g->truncate_size" instead.
The deprecated call "$g->fallocate" does the same, but owing to an
oversight it only allowed 30 bit lengths to be specified,
effectively limiting the maximum size of files created through that
call to 1GB.
Do not confuse this with the guestfish-specific "alloc" and
"sparse" commands which create a file in the host and attach it as
a device.
@lines = $g->fgrep ($pattern, $path);
This calls the external "fgrep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->fgrepi ($pattern, $path);
This calls the external "fgrep -i" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$description = $g->file ($path);
This call uses the standard file(1) command to determine the type
or contents of the file.
This call will also transparently look inside various types of
compressed file.
The exact command which runs is "file -zb path". Note in
particular that the filename is not prepended to the output (the -b
option).
The output depends on the output of the underlying file(1) command
and it can change in future in ways beyond our control. In other
words, the output is not guaranteed by the ABI.
See also: file(1), "$g->vfs_type", "$g->lstat", "$g->is_file",
"$g->is_blockdev" (etc), "$g->is_zero".
$arch = $g->file_architecture ($filename);
This detects the architecture of the binary "filename", and returns
it if known.
Currently defined architectures are:
"i386"
This string is returned for all 32 bit i386, i486, i586, i686
binaries irrespective of the precise processor requirements of
the binary.
"x86_64"
64 bit x86-64.
"sparc"
32 bit SPARC.
"sparc64"
64 bit SPARC V9 and above.
"ia64"
Intel Itanium.
"ppc"
32 bit Power PC.
"ppc64"
64 bit Power PC.
Libguestfs may return other architecture strings in future.
The function works on at least the following types of files:
· many types of Un*x and Linux binary
· many types of Un*x and Linux shared library
· Windows Win32 and Win64 binaries
· Windows Win32 and Win64 DLLs
Win32 binaries and DLLs return "i386".
Win64 binaries and DLLs return "x86_64".
· Linux kernel modules
· Linux new-style initrd images
· some non-x86 Linux vmlinuz kernels
What it can't do currently:
· static libraries (libfoo.a)
· Linux old-style initrd as compressed ext2 filesystem (RHEL 3)
· x86 Linux vmlinuz kernels
x86 vmlinuz images (bzImage format) consist of a mix of 16-,
32- and compressed code, and are horribly hard to unpack. If
you want to find the architecture of a kernel, use the
architecture of the associated initrd or kernel module(s)
instead.
$size = $g->filesize ($file);
This command returns the size of "file" in bytes.
To get other stats about a file, use "$g->stat", "$g->lstat",
"$g->is_dir", "$g->is_file" etc. To get the size of block devices,
use "$g->blockdev_getsize64".
$g->fill ($c, $len, $path);
This command creates a new file called "path". The initial content
of the file is "len" octets of "c", where "c" must be a number in
the range "[0..255]".
To fill a file with zero bytes (sparsely), it is much more
efficient to use "$g->truncate_size". To create a file with a
pattern of repeating bytes use "$g->fill_pattern".
$g->fill_pattern ($pattern, $len, $path);
This function is like "$g->fill" except that it creates a new file
of length "len" containing the repeating pattern of bytes in
"pattern". The pattern is truncated if necessary to ensure the
length of the file is exactly "len" bytes.
@names = $g->find ($directory);
This command lists out all files and directories, recursively,
starting at "directory". It is essentially equivalent to running
the shell command "find directory -print" but some post-processing
happens on the output, described below.
This returns a list of strings without any prefix. Thus if the
directory structure was:
/tmp/a
/tmp/b
/tmp/c/d
then the returned list from "$g->find" "/tmp" would be 4 elements:
a
b
c
c/d
If "directory" is not a directory, then this command returns an
error.
The returned list is sorted.
See also "$g->find0".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->find0 ($directory, $files);
This command lists out all files and directories, recursively,
starting at "directory", placing the resulting list in the external
file called "files".
This command works the same way as "$g->find" with the following
exceptions:
· The resulting list is written to an external file.
· Items (filenames) in the result are separated by "\0"
characters. See find(1) option -print0.
· This command is not limited in the number of names that it can
return.
· The result list is not sorted.
$device = $g->findfs_label ($label);
This command searches the filesystems and returns the one which has
the given label. An error is returned if no such filesystem can be
found.
To find the label of a filesystem, use "$g->vfs_label".
$device = $g->findfs_uuid ($uuid);
This command searches the filesystems and returns the one which has
the given UUID. An error is returned if no such filesystem can be
found.
To find the UUID of a filesystem, use "$g->vfs_uuid".
$status = $g->fsck ($fstype, $device);
This runs the filesystem checker (fsck) on "device" which should
have filesystem type "fstype".
The returned integer is the status. See fsck(8) for the list of
status codes from "fsck".
Notes:
· Multiple status codes can be summed together.
· A non-zero return code can mean "success", for example if
errors have been corrected on the filesystem.
· Checking or repairing NTFS volumes is not supported (by linux-
ntfs).
This command is entirely equivalent to running "fsck -a -t fstype
device".
$append = $g->get_append ();
Return the additional kernel options which are added to the guest
kernel command line.
If "NULL" then no options are added.
$attachmethod = $g->get_attach_method ();
Return the current attach method. See "$g->set_attach_method".
$autosync = $g->get_autosync ();
Get the autosync flag.
$direct = $g->get_direct ();
Return the direct appliance mode flag.
$label = $g->get_e2label ($device);
This returns the ext2/3/4 filesystem label of the filesystem on
"device".
This function is deprecated. In new code, use the "vfs_label" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$uuid = $g->get_e2uuid ($device);
This returns the ext2/3/4 filesystem UUID of the filesystem on
"device".
This function is deprecated. In new code, use the "vfs_uuid" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$memsize = $g->get_memsize ();
This gets the memory size in megabytes allocated to the qemu
subprocess.
If "$g->set_memsize" was not called on this handle, and if
"LIBGUESTFS_MEMSIZE" was not set, then this returns the compiled-in
default value for memsize.
For more information on the architecture of libguestfs, see
guestfs(3).
$network = $g->get_network ();
This returns the enable network flag.
$path = $g->get_path ();
Return the current search path.
This is always non-NULL. If it wasn't set already, then this will
return the default path.
$pgroup = $g->get_pgroup ();
This returns the process group flag.
$pid = $g->get_pid ();
Return the process ID of the qemu subprocess. If there is no qemu
subprocess, then this will return an error.
This is an internal call used for debugging and testing.
$qemu = $g->get_qemu ();
Return the current qemu binary.
This is always non-NULL. If it wasn't set already, then this will
return the default qemu binary name.
$recoveryproc = $g->get_recovery_proc ();
Return the recovery process enabled flag.
$selinux = $g->get_selinux ();
This returns the current setting of the selinux flag which is
passed to the appliance at boot time. See "$g->set_selinux".
For more information on the architecture of libguestfs, see
guestfs(3).
$smp = $g->get_smp ();
This returns the number of virtual CPUs assigned to the appliance.
$state = $g->get_state ();
This returns the current state as an opaque integer. This is only
useful for printing debug and internal error messages.
For more information on states, see guestfs(3).
$trace = $g->get_trace ();
Return the command trace flag.
$mask = $g->get_umask ();
Return the current umask. By default the umask is 022 unless it
has been set by calling "$g->umask".
$verbose = $g->get_verbose ();
This returns the verbose messages flag.
$context = $g->getcon ();
This gets the SELinux security context of the daemon.
See the documentation about SELINUX in guestfs(3), and "$g->setcon"
$xattr = $g->getxattr ($path, $name);
Get a single extended attribute from file "path" named "name".
This call follows symlinks. If you want to lookup an extended
attribute for the symlink itself, use "$g->lgetxattr".
Normally it is better to get all extended attributes from a file in
one go by calling "$g->getxattrs". However some Linux filesystem
implementations are buggy and do not provide a way to list out
attributes. For these filesystems (notably ntfs-3g) you have to
know the names of the extended attributes you want in advance and
call this function.
Extended attribute values are blobs of binary data. If there is no
extended attribute named "name", this returns an error.
See also: "$g->getxattrs", "$g->lgetxattr", attr(5).
@xattrs = $g->getxattrs ($path);
This call lists the extended attributes of the file or directory
"path".
At the system call level, this is a combination of the listxattr(2)
and getxattr(2) calls.
See also: "$g->lgetxattrs", attr(5).
@paths = $g->glob_expand ($pattern);
This command searches for all the pathnames matching "pattern"
according to the wildcard expansion rules used by the shell.
If no paths match, then this returns an empty list (note: not an
error).
It is just a wrapper around the C glob(3) function with flags
"GLOB_MARK|GLOB_BRACE". See that manual page for more details.
@lines = $g->grep ($regex, $path);
This calls the external "grep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->grepi ($regex, $path);
This calls the external "grep -i" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->grub_install ($root, $device);
This command installs GRUB 1 (the Grand Unified Bootloader) on
"device", with the root directory being "root".
Notes:
· There is currently no way in the API to install grub2, which is
used by most modern Linux guests. It is possible to run the
grub2 command from the guest, although see the caveats in
"RUNNING COMMANDS" in guestfs(3).
· This uses "grub-install" from the host. Unfortunately grub is
not always compatible with itself, so this only works in rather
narrow circumstances. Careful testing with each guest version
is advisable.
· If grub-install reports the error "No suitable drive was found
in the generated device map." it may be that you need to
create a "/boot/grub/device.map" file first that contains the
mapping between grub device names and Linux device names. It
is usually sufficient to create a file containing:
(hd0) /dev/vda
replacing "/dev/vda" with the name of the installation device.
@lines = $g->head ($path);
This command returns up to the first 10 lines of a file as a list
of strings.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->head_n ($nrlines, $path);
If the parameter "nrlines" is a positive number, this returns the
first "nrlines" lines of the file "path".
If the parameter "nrlines" is a negative number, this returns lines
from the file "path", excluding the last "nrlines" lines.
If the parameter "nrlines" is zero, this returns an empty list.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$dump = $g->hexdump ($path);
This runs "hexdump -C" on the given "path". The result is the
human-readable, canonical hex dump of the file.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$content = $g->initrd_cat ($initrdpath, $filename);
This command unpacks the file "filename" from the initrd file
called "initrdpath". The filename must be given without the
initial "/" character.
For example, in guestfish you could use the following command to
examine the boot script (usually called "/init") contained in a
Linux initrd or initramfs image:
initrd-cat /boot/initrd-<version>.img init
See also "$g->initrd_list".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@filenames = $g->initrd_list ($path);
This command lists out files contained in an initrd.
The files are listed without any initial "/" character. The files
are listed in the order they appear (not necessarily alphabetical).
Directory names are listed as separate items.
Old Linux kernels (2.4 and earlier) used a compressed ext2
filesystem as initrd. We only support the newer initramfs format
(compressed cpio files).
$wd = $g->inotify_add_watch ($path, $mask);
Watch "path" for the events listed in "mask".
Note that if "path" is a directory then events within that
directory are watched, but this does not happen recursively (in
subdirectories).
Note for non-C or non-Linux callers: the inotify events are defined
by the Linux kernel ABI and are listed in
"/usr/include/sys/inotify.h".
$g->inotify_close ();
This closes the inotify handle which was previously opened by
inotify_init. It removes all watches, throws away any pending
events, and deallocates all resources.
@paths = $g->inotify_files ();
This function is a helpful wrapper around "$g->inotify_read" which
just returns a list of pathnames of objects that were touched. The
returned pathnames are sorted and deduplicated.
$g->inotify_init ($maxevents);
This command creates a new inotify handle. The inotify subsystem
can be used to notify events which happen to objects in the guest
filesystem.
"maxevents" is the maximum number of events which will be queued up
between calls to "$g->inotify_read" or "$g->inotify_files". If
this is passed as 0, then the kernel (or previously set) default is
used. For Linux 2.6.29 the default was 16384 events. Beyond this
limit, the kernel throws away events, but records the fact that it
threw them away by setting a flag "IN_Q_OVERFLOW" in the returned
structure list (see "$g->inotify_read").
Before any events are generated, you have to add some watches to
the internal watch list. See: "$g->inotify_add_watch" and
"$g->inotify_rm_watch".
Queued up events should be read periodically by calling
"$g->inotify_read" (or "$g->inotify_files" which is just a helpful
wrapper around "$g->inotify_read"). If you don't read the events
out often enough then you risk the internal queue overflowing.
The handle should be closed after use by calling
"$g->inotify_close". This also removes any watches automatically.
See also inotify(7) for an overview of the inotify interface as
exposed by the Linux kernel, which is roughly what we expose via
libguestfs. Note that there is one global inotify handle per
libguestfs instance.
@events = $g->inotify_read ();
Return the complete queue of events that have happened since the
previous read call.
If no events have happened, this returns an empty list.
Note: In order to make sure that all events have been read, you
must call this function repeatedly until it returns an empty list.
The reason is that the call will read events up to the maximum
appliance-to-host message size and leave remaining events in the
queue.
$g->inotify_rm_watch ($wd);
Remove a previously defined inotify watch. See
"$g->inotify_add_watch".
$arch = $g->inspect_get_arch ($root);
This returns the architecture of the inspected operating system.
The possible return values are listed under
"$g->file_architecture".
If the architecture could not be determined, then the string
"unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$distro = $g->inspect_get_distro ($root);
This returns the distro (distribution) of the inspected operating
system.
Currently defined distros are:
"archlinux"
Arch Linux.
"centos"
CentOS.
"debian"
Debian.
"fedora"
Fedora.
"gentoo"
Gentoo.
"linuxmint"
Linux Mint.
"mageia"
Mageia.
"mandriva"
Mandriva.
"meego"
MeeGo.
"opensuse"
OpenSUSE.
"pardus"
Pardus.
"redhat-based"
Some Red Hat-derived distro.
"rhel"
Red Hat Enterprise Linux.
"scientificlinux"
Scientific Linux.
"slackware"
Slackware.
"ttylinux"
ttylinux.
"ubuntu"
Ubuntu.
"unknown"
The distro could not be determined.
"windows"
Windows does not have distributions. This string is returned
if the OS type is Windows.
Future versions of libguestfs may return other strings here. The
caller should be prepared to handle any string.
Please read "INSPECTION" in guestfs(3) for more details.
%drives = $g->inspect_get_drive_mappings ($root);
This call is useful for Windows which uses a primitive system of
assigning drive letters (like "C:") to partitions. This inspection
API examines the Windows Registry to find out how disks/partitions
are mapped to drive letters, and returns a hash table as in the
example below:
C => /dev/vda2
E => /dev/vdb1
F => /dev/vdc1
Note that keys are drive letters. For Windows, the key is case
insensitive and just contains the drive letter, without the
customary colon separator character.
In future we may support other operating systems that also used
drive letters, but the keys for those might not be case insensitive
and might be longer than 1 character. For example in OS-9, hard
drives were named "h0", "h1" etc.
For Windows guests, currently only hard drive mappings are
returned. Removable disks (eg. DVD-ROMs) are ignored.
For guests that do not use drive mappings, or if the drive mappings
could not be determined, this returns an empty hash table.
Please read "INSPECTION" in guestfs(3) for more details. See also
"$g->inspect_get_mountpoints", "$g->inspect_get_filesystems".
@filesystems = $g->inspect_get_filesystems ($root);
This returns a list of all the filesystems that we think are
associated with this operating system. This includes the root
filesystem, other ordinary filesystems, and non-mounted devices
like swap partitions.
In the case of a multi-boot virtual machine, it is possible for a
filesystem to be shared between operating systems.
Please read "INSPECTION" in guestfs(3) for more details. See also
"$g->inspect_get_mountpoints".
$format = $g->inspect_get_format ($root);
This returns the format of the inspected operating system. You can
use it to detect install images, live CDs and similar.
Currently defined formats are:
"installed"
This is an installed operating system.
"installer"
The disk image being inspected is not an installed operating
system, but a bootable install disk, live CD, or similar.
"unknown"
The format of this disk image is not known.
Future versions of libguestfs may return other strings here. The
caller should be prepared to handle any string.
Please read "INSPECTION" in guestfs(3) for more details.
$hostname = $g->inspect_get_hostname ($root);
This function returns the hostname of the operating system as found
by inspection of the guest's configuration files.
If the hostname could not be determined, then the string "unknown"
is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$icon = $g->inspect_get_icon ($root [, favicon => $favicon] [,
highquality => $highquality]);
This function returns an icon corresponding to the inspected
operating system. The icon is returned as a buffer containing a
PNG image (re-encoded to PNG if necessary).
If it was not possible to get an icon this function returns a zero-
length (non-NULL) buffer. Callers must check for this case.
Libguestfs will start by looking for a file called
"/etc/favicon.png" or "C:\etc\favicon.png" and if it has the
correct format, the contents of this file will be returned. You
can disable favicons by passing the optional "favicon" boolean as
false (default is true).
If finding the favicon fails, then we look in other places in the
guest for a suitable icon.
If the optional "highquality" boolean is true then only high
quality icons are returned, which means only icons of high
resolution with an alpha channel. The default (false) is to return
any icon we can, even if it is of substandard quality.
Notes:
· Unlike most other inspection API calls, the guest's disks must
be mounted up before you call this, since it needs to read
information from the guest filesystem during the call.
· Security: The icon data comes from the untrusted guest, and
should be treated with caution. PNG files have been known to
contain exploits. Ensure that libpng (or other relevant
libraries) are fully up to date before trying to process or
display the icon.
· The PNG image returned can be any size. It might not be
square. Libguestfs tries to return the largest, highest
quality icon available. The application must scale the icon to
the required size.
· Extracting icons from Windows guests requires the external
"wrestool" program from the "icoutils" package, and several
programs ("bmptopnm", "pnmtopng", "pamcut") from the "netpbm"
package. These must be installed separately.
· Operating system icons are usually trademarks. Seek legal
advice before using trademarks in applications.
$major = $g->inspect_get_major_version ($root);
This returns the major version number of the inspected operating
system.
Windows uses a consistent versioning scheme which is not reflected
in the popular public names used by the operating system. Notably
the operating system known as "Windows 7" is really version 6.1
(ie. major = 6, minor = 1). You can find out the real versions
corresponding to releases of Windows by consulting Wikipedia or
MSDN.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$minor = $g->inspect_get_minor_version ($root);
This returns the minor version number of the inspected operating
system.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in guestfs(3) for more details. See also
"$g->inspect_get_major_version".
%mountpoints = $g->inspect_get_mountpoints ($root);
This returns a hash of where we think the filesystems associated
with this operating system should be mounted. Callers should note
that this is at best an educated guess made by reading
configuration files such as "/etc/fstab". In particular note that
this may return filesystems which are non-existent or not mountable
and callers should be prepared to handle or ignore failures if they
try to mount them.
Each element in the returned hashtable has a key which is the path
of the mountpoint (eg. "/boot") and a value which is the filesystem
that would be mounted there (eg. "/dev/sda1").
Non-mounted devices such as swap devices are not returned in this
list.
For operating systems like Windows which still use drive letters,
this call will only return an entry for the first drive "mounted
on" "/". For information about the mapping of drive letters to
partitions, see "$g->inspect_get_drive_mappings".
Please read "INSPECTION" in guestfs(3) for more details. See also
"$g->inspect_get_filesystems".
$packageformat = $g->inspect_get_package_format ($root);
This function and "$g->inspect_get_package_management" return the
package format and package management tool used by the inspected
operating system. For example for Fedora these functions would
return "rpm" (package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the
package format or if the operating system does not have a real
packaging system (eg. Windows).
Possible strings include: "rpm", "deb", "ebuild", "pisi", "pacman",
"pkgsrc". Future versions of libguestfs may return other strings.
Please read "INSPECTION" in guestfs(3) for more details.
$packagemanagement = $g->inspect_get_package_management ($root);
"$g->inspect_get_package_format" and this function return the
package format and package management tool used by the inspected
operating system. For example for Fedora these functions would
return "rpm" (package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the
package management tool or if the operating system does not have a
real packaging system (eg. Windows).
Possible strings include: "yum", "up2date", "apt" (for all Debian
derivatives), "portage", "pisi", "pacman", "urpmi", "zypper".
Future versions of libguestfs may return other strings.
Please read "INSPECTION" in guestfs(3) for more details.
$product = $g->inspect_get_product_name ($root);
This returns the product name of the inspected operating system.
The product name is generally some freeform string which can be
displayed to the user, but should not be parsed by programs.
If the product name could not be determined, then the string
"unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$variant = $g->inspect_get_product_variant ($root);
This returns the product variant of the inspected operating system.
For Windows guests, this returns the contents of the Registry key
"HKLM\Software\Microsoft\Windows NT\CurrentVersion"
"InstallationType" which is usually a string such as "Client" or
"Server" (other values are possible). This can be used to
distinguish consumer and enterprise versions of Windows that have
the same version number (for example, Windows 7 and Windows 2008
Server are both version 6.1, but the former is "Client" and the
latter is "Server").
For enterprise Linux guests, in future we intend this to return the
product variant such as "Desktop", "Server" and so on. But this is
not implemented at present.
If the product variant could not be determined, then the string
"unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details. See also
"$g->inspect_get_product_name", "$g->inspect_get_major_version".
@roots = $g->inspect_get_roots ();
This function is a convenient way to get the list of root devices,
as returned from a previous call to "$g->inspect_os", but without
redoing the whole inspection process.
This returns an empty list if either no root devices were found or
the caller has not called "$g->inspect_os".
Please read "INSPECTION" in guestfs(3) for more details.
$name = $g->inspect_get_type ($root);
This returns the type of the inspected operating system. Currently
defined types are:
"linux"
Any Linux-based operating system.
"windows"
Any Microsoft Windows operating system.
"freebsd"
FreeBSD.
"netbsd"
NetBSD.
"hurd"
GNU/Hurd.
"unknown"
The operating system type could not be determined.
Future versions of libguestfs may return other strings here. The
caller should be prepared to handle any string.
Please read "INSPECTION" in guestfs(3) for more details.
$controlset = $g->inspect_get_windows_current_control_set ($root);
This returns the Windows CurrentControlSet of the inspected guest.
The CurrentControlSet is a registry key name such as
"ControlSet001".
This call assumes that the guest is Windows and that the Registry
could be examined by inspection. If this is not the case then an
error is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$systemroot = $g->inspect_get_windows_systemroot ($root);
This returns the Windows systemroot of the inspected guest. The
systemroot is a directory path such as "/WINDOWS".
This call assumes that the guest is Windows and that the systemroot
could be determined by inspection. If this is not the case then an
error is returned.
Please read "INSPECTION" in guestfs(3) for more details.
$live = $g->inspect_is_live ($root);
If "$g->inspect_get_format" returns "installer" (this is an install
disk), then this returns true if a live image was detected on the
disk.
Please read "INSPECTION" in guestfs(3) for more details.
$multipart = $g->inspect_is_multipart ($root);
If "$g->inspect_get_format" returns "installer" (this is an install
disk), then this returns true if the disk is part of a set.
Please read "INSPECTION" in guestfs(3) for more details.
$netinst = $g->inspect_is_netinst ($root);
If "$g->inspect_get_format" returns "installer" (this is an install
disk), then this returns true if the disk is a network installer,
ie. not a self-contained install CD but one which is likely to
require network access to complete the install.
Please read "INSPECTION" in guestfs(3) for more details.
@applications = $g->inspect_list_applications ($root);
Return the list of applications installed in the operating system.
Note: This call works differently from other parts of the
inspection API. You have to call "$g->inspect_os", then
"$g->inspect_get_mountpoints", then mount up the disks, before
calling this. Listing applications is a significantly more
difficult operation which requires access to the full filesystem.
Also note that unlike the other "$g->inspect_get_*" calls which are
just returning data cached in the libguestfs handle, this call
actually reads parts of the mounted filesystems during the call.
This returns an empty list if the inspection code was not able to
determine the list of applications.
The application structure contains the following fields:
"app_name"
The name of the application. For Red Hat-derived and Debian-
derived Linux guests, this is the package name.
"app_display_name"
The display name of the application, sometimes localized to the
install language of the guest operating system.
If unavailable this is returned as an empty string "". Callers
needing to display something can use "app_name" instead.
"app_epoch"
For package managers which use epochs, this contains the epoch
of the package (an integer). If unavailable, this is returned
as 0.
"app_version"
The version string of the application or package. If
unavailable this is returned as an empty string "".
"app_release"
The release string of the application or package, for package
managers that use this. If unavailable this is returned as an
empty string "".
"app_install_path"
The installation path of the application (on operating systems
such as Windows which use installation paths). This path is in
the format used by the guest operating system, it is not a
libguestfs path.
If unavailable this is returned as an empty string "".
"app_trans_path"
The install path translated into a libguestfs path. If
unavailable this is returned as an empty string "".
"app_publisher"
The name of the publisher of the application, for package
managers that use this. If unavailable this is returned as an
empty string "".
"app_url"
The URL (eg. upstream URL) of the application. If unavailable
this is returned as an empty string "".
"app_source_package"
For packaging systems which support this, the name of the
source package. If unavailable this is returned as an empty
string "".
"app_summary"
A short (usually one line) description of the application or
package. If unavailable this is returned as an empty string
"".
"app_description"
A longer description of the application or package. If
unavailable this is returned as an empty string "".
Please read "INSPECTION" in guestfs(3) for more details.
@roots = $g->inspect_os ();
This function uses other libguestfs functions and certain
heuristics to inspect the disk(s) (usually disks belonging to a
virtual machine), looking for operating systems.
The list returned is empty if no operating systems were found.
If one operating system was found, then this returns a list with a
single element, which is the name of the root filesystem of this
operating system. It is also possible for this function to return
a list containing more than one element, indicating a dual-boot or
multi-boot virtual machine, with each element being the root
filesystem of one of the operating systems.
You can pass the root string(s) returned to other
"$g->inspect_get_*" functions in order to query further information
about each operating system, such as the name and version.
This function uses other libguestfs features such as "$g->mount_ro"
and "$g->umount_all" in order to mount and unmount filesystems and
look at the contents. This should be called with no disks
currently mounted. The function may also use Augeas, so any
existing Augeas handle will be closed.
This function cannot decrypt encrypted disks. The caller must do
that first (supplying the necessary keys) if the disk is encrypted.
Please read "INSPECTION" in guestfs(3) for more details.
See also "$g->list_filesystems".
$flag = $g->is_blockdev ($path);
This returns "true" if and only if there is a block device with the
given "path" name.
See also "$g->stat".
$busy = $g->is_busy ();
This returns true iff this handle is busy processing a command (in
the "BUSY" state).
For more information on states, see guestfs(3).
$flag = $g->is_chardev ($path);
This returns "true" if and only if there is a character device with
the given "path" name.
See also "$g->stat".
$config = $g->is_config ();
This returns true iff this handle is being configured (in the
"CONFIG" state).
For more information on states, see guestfs(3).
$dirflag = $g->is_dir ($path);
This returns "true" if and only if there is a directory with the
given "path" name. Note that it returns false for other objects
like files.
See also "$g->stat".
$flag = $g->is_fifo ($path);
This returns "true" if and only if there is a FIFO (named pipe)
with the given "path" name.
See also "$g->stat".
$fileflag = $g->is_file ($path);
This returns "true" if and only if there is a regular file with the
given "path" name. Note that it returns false for other objects
like directories.
See also "$g->stat".
$launching = $g->is_launching ();
This returns true iff this handle is launching the subprocess (in
the "LAUNCHING" state).
For more information on states, see guestfs(3).
$lvflag = $g->is_lv ($device);
This command tests whether "device" is a logical volume, and
returns true iff this is the case.
$ready = $g->is_ready ();
This returns true iff this handle is ready to accept commands (in
the "READY" state).
For more information on states, see guestfs(3).
$flag = $g->is_socket ($path);
This returns "true" if and only if there is a Unix domain socket
with the given "path" name.
See also "$g->stat".
$flag = $g->is_symlink ($path);
This returns "true" if and only if there is a symbolic link with
the given "path" name.
See also "$g->stat".
$zeroflag = $g->is_zero ($path);
This returns true iff the file exists and the file is empty or it
contains all zero bytes.
$zeroflag = $g->is_zero_device ($device);
This returns true iff the device exists and contains all zero
bytes.
Note that for large devices this can take a long time to run.
$g->kill_subprocess ();
This kills the qemu subprocess.
Do not call this. See: "$g->shutdown" instead.
This function is deprecated. In new code, use the "shutdown" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->launch ();
Internally libguestfs is implemented by running a virtual machine
using qemu(1).
You should call this after configuring the handle (eg. adding
drives) but before performing any actions.
Do not call "$g->launch" twice on the same handle. Although it
will not give an error (for historical reasons), the precise
behaviour when you do this is not well defined. Handles are very
cheap to create, so create a new one for each launch.
$g->lchown ($owner, $group, $path);
Change the file owner to "owner" and group to "group". This is
like "$g->chown" but if "path" is a symlink then the link itself is
changed, not the target.
Only numeric uid and gid are supported. If you want to use names,
you will need to locate and parse the password file yourself
(Augeas support makes this relatively easy).
$xattr = $g->lgetxattr ($path, $name);
Get a single extended attribute from file "path" named "name". If
"path" is a symlink, then this call returns an extended attribute
from the symlink.
Normally it is better to get all extended attributes from a file in
one go by calling "$g->getxattrs". However some Linux filesystem
implementations are buggy and do not provide a way to list out
attributes. For these filesystems (notably ntfs-3g) you have to
know the names of the extended attributes you want in advance and
call this function.
Extended attribute values are blobs of binary data. If there is no
extended attribute named "name", this returns an error.
See also: "$g->lgetxattrs", "$g->getxattr", attr(5).
@xattrs = $g->lgetxattrs ($path);
This is the same as "$g->getxattrs", but if "path" is a symbolic
link, then it returns the extended attributes of the link itself.
@mounttags = $g->list_9p ();
List all 9p filesystems attached to the guest. A list of mount
tags is returned.
@devices = $g->list_devices ();
List all the block devices.
The full block device names are returned, eg. "/dev/sda".
See also "$g->list_filesystems".
@devices = $g->list_dm_devices ();
List all device mapper devices.
The returned list contains "/dev/mapper/*" devices, eg. ones
created by a previous call to "$g->luks_open".
Device mapper devices which correspond to logical volumes are not
returned in this list. Call "$g->lvs" if you want to list logical
volumes.
%fses = $g->list_filesystems ();
This inspection command looks for filesystems on partitions, block
devices and logical volumes, returning a list of devices containing
filesystems and their type.
The return value is a hash, where the keys are the devices
containing filesystems, and the values are the filesystem types.
For example:
"/dev/sda1" => "ntfs"
"/dev/sda2" => "ext2"
"/dev/vg_guest/lv_root" => "ext4"
"/dev/vg_guest/lv_swap" => "swap"
The value can have the special value "unknown", meaning the content
of the device is undetermined or empty. "swap" means a Linux swap
partition.
This command runs other libguestfs commands, which might include
"$g->mount" and "$g->umount", and therefore you should use this
soon after launch and only when nothing is mounted.
Not all of the filesystems returned will be mountable. In
particular, swap partitions are returned in the list. Also this
command does not check that each filesystem found is valid and
mountable, and some filesystems might be mountable but require
special options. Filesystems may not all belong to a single
logical operating system (use "$g->inspect_os" to look for OSes).
@devices = $g->list_md_devices ();
List all Linux md devices.
@partitions = $g->list_partitions ();
List all the partitions detected on all block devices.
The full partition device names are returned, eg. "/dev/sda1"
This does not return logical volumes. For that you will need to
call "$g->lvs".
See also "$g->list_filesystems".
$listing = $g->ll ($directory);
List the files in "directory" (relative to the root directory,
there is no cwd) in the format of 'ls -la'.
This command is mostly useful for interactive sessions. It is not
intended that you try to parse the output string.
$g->ln ($target, $linkname);
This command creates a hard link using the "ln" command.
$g->ln_f ($target, $linkname);
This command creates a hard link using the "ln -f" command. The -f
option removes the link ("linkname") if it exists already.
$g->ln_s ($target, $linkname);
This command creates a symbolic link using the "ln -s" command.
$g->ln_sf ($target, $linkname);
This command creates a symbolic link using the "ln -sf" command,
The -f option removes the link ("linkname") if it exists already.
$g->lremovexattr ($xattr, $path);
This is the same as "$g->removexattr", but if "path" is a symbolic
link, then it removes an extended attribute of the link itself.
@listing = $g->ls ($directory);
List the files in "directory" (relative to the root directory,
there is no cwd). The '.' and '..' entries are not returned, but
hidden files are shown.
This command is mostly useful for interactive sessions. Programs
should probably use "$g->readdir" instead.
$g->lsetxattr ($xattr, $val, $vallen, $path);
This is the same as "$g->setxattr", but if "path" is a symbolic
link, then it sets an extended attribute of the link itself.
%statbuf = $g->lstat ($path);
Returns file information for the given "path".
This is the same as "$g->stat" except that if "path" is a symbolic
link, then the link is stat-ed, not the file it refers to.
This is the same as the lstat(2) system call.
@statbufs = $g->lstatlist ($path, \@names);
This call allows you to perform the "$g->lstat" operation on
multiple files, where all files are in the directory "path".
"names" is the list of files from this directory.
On return you get a list of stat structs, with a one-to-one
correspondence to the "names" list. If any name did not exist or
could not be lstat'd, then the "ino" field of that structure is set
to "-1".
This call is intended for programs that want to efficiently list a
directory contents without making many round-trips. See also
"$g->lxattrlist" for a similarly efficient call for getting
extended attributes. Very long directory listings might cause the
protocol message size to be exceeded, causing this call to fail.
The caller must split up such requests into smaller groups of
names.
$g->luks_add_key ($device, $key, $newkey, $keyslot);
This command adds a new key on LUKS device "device". "key" is any
existing key, and is used to access the device. "newkey" is the
new key to add. "keyslot" is the key slot that will be replaced.
Note that if "keyslot" already contains a key, then this command
will fail. You have to use "$g->luks_kill_slot" first to remove
that key.
$g->luks_close ($device);
This closes a LUKS device that was created earlier by
"$g->luks_open" or "$g->luks_open_ro". The "device" parameter must
be the name of the LUKS mapping device (ie. "/dev/mapper/mapname")
and not the name of the underlying block device.
$g->luks_format ($device, $key, $keyslot);
This command erases existing data on "device" and formats the
device as a LUKS encrypted device. "key" is the initial key, which
is added to key slot "slot". (LUKS supports 8 key slots, numbered
0-7).
$g->luks_format_cipher ($device, $key, $keyslot, $cipher);
This command is the same as "$g->luks_format" but it also allows
you to set the "cipher" used.
$g->luks_kill_slot ($device, $key, $keyslot);
This command deletes the key in key slot "keyslot" from the
encrypted LUKS device "device". "key" must be one of the other
keys.
$g->luks_open ($device, $key, $mapname);
This command opens a block device which has been encrypted
according to the Linux Unified Key Setup (LUKS) standard.
"device" is the encrypted block device or partition.
The caller must supply one of the keys associated with the LUKS
block device, in the "key" parameter.
This creates a new block device called "/dev/mapper/mapname".
Reads and writes to this block device are decrypted from and
encrypted to the underlying "device" respectively.
If this block device contains LVM volume groups, then calling
"$g->vgscan" followed by "$g->vg_activate_all" will make them
visible.
Use "$g->list_dm_devices" to list all device mapper devices.
$g->luks_open_ro ($device, $key, $mapname);
This is the same as "$g->luks_open" except that a read-only mapping
is created.
$g->lvcreate ($logvol, $volgroup, $mbytes);
This creates an LVM logical volume called "logvol" on the volume
group "volgroup", with "size" megabytes.
$lv = $g->lvm_canonical_lv_name ($lvname);
This converts alternative naming schemes for LVs that you might
find to the canonical name. For example, "/dev/mapper/VG-LV" is
converted to "/dev/VG/LV".
This command returns an error if the "lvname" parameter does not
refer to a logical volume.
See also "$g->is_lv".
$g->lvm_clear_filter ();
This undoes the effect of "$g->lvm_set_filter". LVM will be able
to see every block device.
This command also clears the LVM cache and performs a volume group
scan.
$g->lvm_remove_all ();
This command removes all LVM logical volumes, volume groups and
physical volumes.
$g->lvm_set_filter (\@devices);
This sets the LVM device filter so that LVM will only be able to
"see" the block devices in the list "devices", and will ignore all
other attached block devices.
Where disk image(s) contain duplicate PVs or VGs, this command is
useful to get LVM to ignore the duplicates, otherwise LVM can get
confused. Note also there are two types of duplication possible:
either cloned PVs/VGs which have identical UUIDs; or VGs that are
not cloned but just happen to have the same name. In normal
operation you cannot create this situation, but you can do it
outside LVM, eg. by cloning disk images or by bit twiddling inside
the LVM metadata.
This command also clears the LVM cache and performs a volume group
scan.
You can filter whole block devices or individual partitions.
You cannot use this if any VG is currently in use (eg. contains a
mounted filesystem), even if you are not filtering out that VG.
$g->lvremove ($device);
Remove an LVM logical volume "device", where "device" is the path
to the LV, such as "/dev/VG/LV".
You can also remove all LVs in a volume group by specifying the VG
name, "/dev/VG".
$g->lvrename ($logvol, $newlogvol);
Rename a logical volume "logvol" with the new name "newlogvol".
$g->lvresize ($device, $mbytes);
This resizes (expands or shrinks) an existing LVM logical volume to
"mbytes". When reducing, data in the reduced part is lost.
$g->lvresize_free ($lv, $percent);
This expands an existing logical volume "lv" so that it fills "pc"%
of the remaining free space in the volume group. Commonly you
would call this with pc = 100 which expands the logical volume as
much as possible, using all remaining free space in the volume
group.
@logvols = $g->lvs ();
List all the logical volumes detected. This is the equivalent of
the lvs(8) command.
This returns a list of the logical volume device names (eg.
"/dev/VolGroup00/LogVol00").
See also "$g->lvs_full", "$g->list_filesystems".
@logvols = $g->lvs_full ();
List all the logical volumes detected. This is the equivalent of
the lvs(8) command. The "full" version includes all fields.
$uuid = $g->lvuuid ($device);
This command returns the UUID of the LVM LV "device".
@xattrs = $g->lxattrlist ($path, \@names);
This call allows you to get the extended attributes of multiple
files, where all files are in the directory "path". "names" is the
list of files from this directory.
On return you get a flat list of xattr structs which must be
interpreted sequentially. The first xattr struct always has a
zero-length "attrname". "attrval" in this struct is zero-length to
indicate there was an error doing "lgetxattr" for this file, or is
a C string which is a decimal number (the number of following
attributes for this file, which could be "0"). Then after the
first xattr struct are the zero or more attributes for the first
named file. This repeats for the second and subsequent files.
This call is intended for programs that want to efficiently list a
directory contents without making many round-trips. See also
"$g->lstatlist" for a similarly efficient call for getting standard
stats. Very long directory listings might cause the protocol
message size to be exceeded, causing this call to fail. The caller
must split up such requests into smaller groups of names.
$g->md_create ($name, \@devices [, missingbitmap => $missingbitmap] [,
nrdevices => $nrdevices] [, spare => $spare] [, chunk => $chunk] [,
level => $level]);
Create a Linux md (RAID) device named "name" on the devices in the
list "devices".
The optional parameters are:
"missingbitmap"
A bitmap of missing devices. If a bit is set it means that a
missing device is added to the array. The least significant
bit corresponds to the first device in the array.
As examples:
If "devices = ["/dev/sda"]" and "missingbitmap = 0x1" then the
resulting array would be "[<missing>, "/dev/sda"]".
If "devices = ["/dev/sda"]" and "missingbitmap = 0x2" then the
resulting array would be "["/dev/sda", <missing>]".
This defaults to 0 (no missing devices).
The length of "devices" + the number of bits set in
"missingbitmap" must equal "nrdevices" + "spare".
"nrdevices"
The number of active RAID devices.
If not set, this defaults to the length of "devices" plus the
number of bits set in "missingbitmap".
"spare"
The number of spare devices.
If not set, this defaults to 0.
"chunk"
The chunk size in bytes.
"level"
The RAID level, which can be one of: linear, raid0, 0, stripe,
raid1, 1, mirror, raid4, 4, raid5, 5, raid6, 6, raid10, 10.
Some of these are synonymous, and more levels may be added in
future.
If not set, this defaults to "raid1".
%info = $g->md_detail ($md);
This command exposes the output of 'mdadm -DY <md>'. The following
fields are usually present in the returned hash. Other fields may
also be present.
"level"
The raid level of the MD device.
"devices"
The number of underlying devices in the MD device.
"metadata"
The metadata version used.
"uuid"
The UUID of the MD device.
"name"
The name of the MD device.
$g->md_stop ($md);
This command deactivates the MD array named "md". The device is
stopped, but it is not destroyed or zeroed.
$g->mkdir ($path);
Create a directory named "path".
$g->mkdir_mode ($path, $mode);
This command creates a directory, setting the initial permissions
of the directory to "mode".
For common Linux filesystems, the actual mode which is set will be
"mode & ~umask & 01777". Non-native-Linux filesystems may
interpret the mode in other ways.
See also "$g->mkdir", "$g->umask"
$g->mkdir_p ($path);
Create a directory named "path", creating any parent directories as
necessary. This is like the "mkdir -p" shell command.
$dir = $g->mkdtemp ($tmpl);
This command creates a temporary directory. The "tmpl" parameter
should be a full pathname for the temporary directory name with the
final six characters being "XXXXXX".
For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the
second one being suitable for Windows filesystems.
The name of the temporary directory that was created is returned.
The temporary directory is created with mode 0700 and is owned by
root.
The caller is responsible for deleting the temporary directory and
its contents after use.
See also: mkdtemp(3)
$g->mke2fs_J ($fstype, $blocksize, $device, $journal);
This creates an ext2/3/4 filesystem on "device" with an external
journal on "journal". It is equivalent to the command:
mke2fs -t fstype -b blocksize -J device=<journal> <device>
See also "$g->mke2journal".
$g->mke2fs_JL ($fstype, $blocksize, $device, $label);
This creates an ext2/3/4 filesystem on "device" with an external
journal on the journal labeled "label".
See also "$g->mke2journal_L".
$g->mke2fs_JU ($fstype, $blocksize, $device, $uuid);
This creates an ext2/3/4 filesystem on "device" with an external
journal on the journal with UUID "uuid".
See also "$g->mke2journal_U".
$g->mke2journal ($blocksize, $device);
This creates an ext2 external journal on "device". It is
equivalent to the command:
mke2fs -O journal_dev -b blocksize device
$g->mke2journal_L ($blocksize, $label, $device);
This creates an ext2 external journal on "device" with label
"label".
$g->mke2journal_U ($blocksize, $uuid, $device);
This creates an ext2 external journal on "device" with UUID "uuid".
$g->mkfifo ($mode, $path);
This call creates a FIFO (named pipe) called "path" with mode
"mode". It is just a convenient wrapper around "$g->mknod".
The mode actually set is affected by the umask.
$g->mkfs ($fstype, $device);
This creates a filesystem on "device" (usually a partition or LVM
logical volume). The filesystem type is "fstype", for example
"ext3".
$g->mkfs_b ($fstype, $blocksize, $device);
This call is similar to "$g->mkfs", but it allows you to control
the block size of the resulting filesystem. Supported block sizes
depend on the filesystem type, but typically they are 1024, 2048 or
4096 only.
For VFAT and NTFS the "blocksize" parameter is treated as the
requested cluster size.
This function is deprecated. In new code, use the "mkfs_opts" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->mkfs_opts ($fstype, $device [, blocksize => $blocksize] [, features
=> $features] [, inode => $inode] [, sectorsize => $sectorsize]);
This function creates a filesystem on "device". The filesystem
type is "fstype", for example "ext3".
The optional arguments are:
"blocksize"
The filesystem block size. Supported block sizes depend on the
filesystem type, but typically they are 1024, 2048 or 4096 for
Linux ext2/3 filesystems.
For VFAT and NTFS the "blocksize" parameter is treated as the
requested cluster size.
For UFS block sizes, please see mkfs.ufs(8).
"features"
This passes the -O parameter to the external mkfs program.
For certain filesystem types, this allows extra filesystem
features to be selected. See mke2fs(8) and mkfs.ufs(8) for
more details.
You cannot use this optional parameter with the "gfs" or "gfs2"
filesystem type.
"inode"
This passes the -I parameter to the external mke2fs(8) program
which sets the inode size (only for ext2/3/4 filesystems at
present).
"sectorsize"
This passes the -S parameter to external mkfs.ufs(8) program,
which sets sector size for ufs filesystem.
$g->mkmountpoint ($exemptpath);
"$g->mkmountpoint" and "$g->rmmountpoint" are specialized calls
that can be used to create extra mountpoints before mounting the
first filesystem.
These calls are only necessary in some very limited circumstances,
mainly the case where you want to mount a mix of unrelated and/or
read-only filesystems together.
For example, live CDs often contain a "Russian doll" nest of
filesystems, an ISO outer layer, with a squashfs image inside, with
an ext2/3 image inside that. You can unpack this as follows in
guestfish:
add-ro Fedora-11-i686-Live.iso
run
mkmountpoint /cd
mkmountpoint /sqsh
mkmountpoint /ext3fs
mount /dev/sda /cd
mount-loop /cd/LiveOS/squashfs.img /sqsh
mount-loop /sqsh/LiveOS/ext3fs.img /ext3fs
The inner filesystem is now unpacked under the /ext3fs mountpoint.
"$g->mkmountpoint" is not compatible with "$g->umount_all". You
may get unexpected errors if you try to mix these calls. It is
safest to manually unmount filesystems and remove mountpoints after
use.
"$g->umount_all" unmounts filesystems by sorting the paths longest
first, so for this to work for manual mountpoints, you must ensure
that the innermost mountpoints have the longest pathnames, as in
the example code above.
For more details see
<https://bugzilla.redhat.com/show_bug.cgi?id=599503>
Autosync [see "$g->set_autosync", this is set by default on
handles] can cause "$g->umount_all" to be called when the handle is
closed which can also trigger these issues.
$g->mknod ($mode, $devmajor, $devminor, $path);
This call creates block or character special devices, or named
pipes (FIFOs).
The "mode" parameter should be the mode, using the standard
constants. "devmajor" and "devminor" are the device major and
minor numbers, only used when creating block and character special
devices.
Note that, just like mknod(2), the mode must be bitwise OR'd with
S_IFBLK, S_IFCHR, S_IFIFO or S_IFSOCK (otherwise this call just
creates a regular file). These constants are available in the
standard Linux header files, or you can use "$g->mknod_b",
"$g->mknod_c" or "$g->mkfifo" which are wrappers around this
command which bitwise OR in the appropriate constant for you.
The mode actually set is affected by the umask.
$g->mknod_b ($mode, $devmajor, $devminor, $path);
This call creates a block device node called "path" with mode
"mode" and device major/minor "devmajor" and "devminor". It is
just a convenient wrapper around "$g->mknod".
The mode actually set is affected by the umask.
$g->mknod_c ($mode, $devmajor, $devminor, $path);
This call creates a char device node called "path" with mode "mode"
and device major/minor "devmajor" and "devminor". It is just a
convenient wrapper around "$g->mknod".
The mode actually set is affected by the umask.
$g->mkswap ($device);
Create a swap partition on "device".
$g->mkswap_L ($label, $device);
Create a swap partition on "device" with label "label".
Note that you cannot attach a swap label to a block device (eg.
"/dev/sda"), just to a partition. This appears to be a limitation
of the kernel or swap tools.
$g->mkswap_U ($uuid, $device);
Create a swap partition on "device" with UUID "uuid".
$g->mkswap_file ($path);
Create a swap file.
This command just writes a swap file signature to an existing file.
To create the file itself, use something like "$g->fallocate".
$g->modprobe ($modulename);
This loads a kernel module in the appliance.
The kernel module must have been whitelisted when libguestfs was
built (see "appliance/kmod.whitelist.in" in the source).
$g->mount ($device, $mountpoint);
Mount a guest disk at a position in the filesystem. Block devices
are named "/dev/sda", "/dev/sdb" and so on, as they were added to
the guest. If those block devices contain partitions, they will
have the usual names (eg. "/dev/sda1"). Also LVM
"/dev/VG/LV"-style names can be used.
The rules are the same as for mount(2): A filesystem must first be
mounted on "/" before others can be mounted. Other filesystems can
only be mounted on directories which already exist.
The mounted filesystem is writable, if we have sufficient
permissions on the underlying device.
Before libguestfs 1.13.16, this call implicitly added the options
"sync" and "noatime". The "sync" option greatly slowed writes and
caused many problems for users. If your program might need to work
with older versions of libguestfs, use "$g->mount_options" instead
(using an empty string for the first parameter if you don't want
any options).
$g->mount_9p ($mounttag, $mountpoint [, options => $options]);
Mount the virtio-9p filesystem with the tag "mounttag" on the
directory "mountpoint".
If required, "trans=virtio" will be automatically added to the
options. Any other options required can be passed in the optional
"options" parameter.
$g->mount_loop ($file, $mountpoint);
This command lets you mount "file" (a filesystem image in a file)
on a mount point. It is entirely equivalent to the command "mount
-o loop file mountpoint".
$g->mount_options ($options, $device, $mountpoint);
This is the same as the "$g->mount" command, but it allows you to
set the mount options as for the mount(8)-o flag.
If the "options" parameter is an empty string, then no options are
passed (all options default to whatever the filesystem uses).
$g->mount_ro ($device, $mountpoint);
This is the same as the "$g->mount" command, but it mounts the
filesystem with the read-only (-o ro) flag.
$g->mount_vfs ($options, $vfstype, $device, $mountpoint);
This is the same as the "$g->mount" command, but it allows you to
set both the mount options and the vfstype as for the mount(8)-o
and -t flags.
%mps = $g->mountpoints ();
This call is similar to "$g->mounts". That call returns a list of
devices. This one returns a hash table (map) of device name to
directory where the device is mounted.
@devices = $g->mounts ();
This returns the list of currently mounted filesystems. It returns
the list of devices (eg. "/dev/sda1", "/dev/VG/LV").
Some internal mounts are not shown.
See also: "$g->mountpoints"
$g->mv ($src, $dest);
This moves a file from "src" to "dest" where "dest" is either a
destination filename or destination directory.
$nrdisks = $g->nr_devices ();
This returns the number of whole block devices that were added.
This is the same as the number of devices that would be returned if
you called "$g->list_devices".
To find out the maximum number of devices that could be added, call
"$g->max_disks".
$status = $g->ntfs_3g_probe ($rw, $device);
This command runs the ntfs-3g.probe(8) command which probes an NTFS
"device" for mountability. (Not all NTFS volumes can be mounted
read-write, and some cannot be mounted at all).
"rw" is a boolean flag. Set it to true if you want to test if the
volume can be mounted read-write. Set it to false if you want to
test if the volume can be mounted read-only.
The return value is an integer which 0 if the operation would
succeed, or some non-zero value documented in the ntfs-3g.probe(8)
manual page.
$g->ntfsresize ($device);
This command resizes an NTFS filesystem, expanding or shrinking it
to the size of the underlying device.
Note: After the resize operation, the filesystem is marked as
requiring a consistency check (for safety). You have to boot into
Windows to perform this check and clear this condition.
Furthermore, ntfsresize refuses to resize filesystems which have
been marked in this way. So in effect it is not possible to call
ntfsresize multiple times on a single filesystem without booting
into Windows between each resize.
See also ntfsresize(8).
This function is deprecated. In new code, use the
"ntfsresize_opts" call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->ntfsresize_opts ($device [, size => $size] [, force => $force]);
This command resizes an NTFS filesystem, expanding or shrinking it
to the size of the underlying device.
The optional parameters are:
"size"
The new size (in bytes) of the filesystem. If omitted, the
filesystem is resized to fit the container (eg. partition).
"force"
If this option is true, then force the resize of the filesystem
even if the filesystem is marked as requiring a consistency
check.
After the resize operation, the filesystem is always marked as
requiring a consistency check (for safety). You have to boot
into Windows to perform this check and clear this condition.
If you don't set the "force" option then it is not possible to
call "$g->ntfsresize_opts" multiple times on a single
filesystem without booting into Windows between each resize.
See also ntfsresize(8).
$g->ntfsresize_size ($device, $size);
This command is the same as "$g->ntfsresize" except that it allows
you to specify the new size (in bytes) explicitly.
This function is deprecated. In new code, use the
"ntfsresize_opts" call instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->part_add ($device, $prlogex, $startsect, $endsect);
This command adds a partition to "device". If there is no
partition table on the device, call "$g->part_init" first.
The "prlogex" parameter is the type of partition. Normally you
should pass "p" or "primary" here, but MBR partition tables also
support "l" (or "logical") and "e" (or "extended") partition types.
"startsect" and "endsect" are the start and end of the partition in
sectors. "endsect" may be negative, which means it counts
backwards from the end of the disk ("-1" is the last sector).
Creating a partition which covers the whole disk is not so easy.
Use "$g->part_disk" to do that.
$g->part_del ($device, $partnum);
This command deletes the partition numbered "partnum" on "device".
Note that in the case of MBR partitioning, deleting an extended
partition also deletes any logical partitions it contains.
$g->part_disk ($device, $parttype);
This command is simply a combination of "$g->part_init" followed by
"$g->part_add" to create a single primary partition covering the
whole disk.
"parttype" is the partition table type, usually "mbr" or "gpt", but
other possible values are described in "$g->part_init".
$bootable = $g->part_get_bootable ($device, $partnum);
This command returns true if the partition "partnum" on "device"
has the bootable flag set.
See also "$g->part_set_bootable".
$idbyte = $g->part_get_mbr_id ($device, $partnum);
Returns the MBR type byte (also known as the ID byte) from the
numbered partition "partnum".
Note that only MBR (old DOS-style) partitions have type bytes. You
will get undefined results for other partition table types (see
"$g->part_get_parttype").
$parttype = $g->part_get_parttype ($device);
This command examines the partition table on "device" and returns
the partition table type (format) being used.
Common return values include: "msdos" (a DOS/Windows style MBR
partition table), "gpt" (a GPT/EFI-style partition table). Other
values are possible, although unusual. See "$g->part_init" for a
full list.
$g->part_init ($device, $parttype);
This creates an empty partition table on "device" of one of the
partition types listed below. Usually "parttype" should be either
"msdos" or "gpt" (for large disks).
Initially there are no partitions. Following this, you should call
"$g->part_add" for each partition required.
Possible values for "parttype" are:
efi
gpt Intel EFI / GPT partition table.
This is recommended for >= 2 TB partitions that will be
accessed from Linux and Intel-based Mac OS X. It also has
limited backwards compatibility with the "mbr" format.
mbr
msdos
The standard PC "Master Boot Record" (MBR) format used by MS-
DOS and Windows. This partition type will only work for device
sizes up to 2 TB. For large disks we recommend using "gpt".
Other partition table types that may work but are not supported
include:
aix AIX disk labels.
amiga
rdb Amiga "Rigid Disk Block" format.
bsd BSD disk labels.
dasd
DASD, used on IBM mainframes.
dvh MIPS/SGI volumes.
mac Old Mac partition format. Modern Macs use "gpt".
pc98
NEC PC-98 format, common in Japan apparently.
sun Sun disk labels.
@partitions = $g->part_list ($device);
This command parses the partition table on "device" and returns the
list of partitions found.
The fields in the returned structure are:
part_num
Partition number, counting from 1.
part_start
Start of the partition in bytes. To get sectors you have to
divide by the device's sector size, see "$g->blockdev_getss".
part_end
End of the partition in bytes.
part_size
Size of the partition in bytes.
$g->part_set_bootable ($device, $partnum, $bootable);
This sets the bootable flag on partition numbered "partnum" on
device "device". Note that partitions are numbered from 1.
The bootable flag is used by some operating systems (notably
Windows) to determine which partition to boot from. It is by no
means universally recognized.
$g->part_set_mbr_id ($device, $partnum, $idbyte);
Sets the MBR type byte (also known as the ID byte) of the numbered
partition "partnum" to "idbyte". Note that the type bytes quoted
in most documentation are in fact hexadecimal numbers, but usually
documented without any leading "0x" which might be confusing.
Note that only MBR (old DOS-style) partitions have type bytes. You
will get undefined results for other partition table types (see
"$g->part_get_parttype").
$g->part_set_name ($device, $partnum, $name);
This sets the partition name on partition numbered "partnum" on
device "device". Note that partitions are numbered from 1.
The partition name can only be set on certain types of partition
table. This works on "gpt" but not on "mbr" partitions.
$device = $g->part_to_dev ($partition);
This function takes a partition name (eg. "/dev/sdb1") and removes
the partition number, returning the device name (eg. "/dev/sdb").
The named partition must exist, for example as a string returned
from "$g->list_partitions".
See also "$g->part_to_partnum", "$g->device_index".
$partnum = $g->part_to_partnum ($partition);
This function takes a partition name (eg. "/dev/sdb1") and returns
the partition number (eg. 1).
The named partition must exist, for example as a string returned
from "$g->list_partitions".
See also "$g->part_to_dev".
$g->ping_daemon ();
This is a test probe into the guestfs daemon running inside the
qemu subprocess. Calling this function checks that the daemon
responds to the ping message, without affecting the daemon or
attached block device(s) in any other way.
$content = $g->pread ($path, $count, $offset);
This command lets you read part of a file. It reads "count" bytes
of the file, starting at "offset", from file "path".
This may read fewer bytes than requested. For further details see
the pread(2) system call.
See also "$g->pwrite", "$g->pread_device".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$content = $g->pread_device ($device, $count, $offset);
This command lets you read part of a file. It reads "count" bytes
of "device", starting at "offset".
This may read fewer bytes than requested. For further details see
the pread(2) system call.
See also "$g->pread".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->pvcreate ($device);
This creates an LVM physical volume on the named "device", where
"device" should usually be a partition name such as "/dev/sda1".
$g->pvremove ($device);
This wipes a physical volume "device" so that LVM will no longer
recognise it.
The implementation uses the "pvremove" command which refuses to
wipe physical volumes that contain any volume groups, so you have
to remove those first.
$g->pvresize ($device);
This resizes (expands or shrinks) an existing LVM physical volume
to match the new size of the underlying device.
$g->pvresize_size ($device, $size);
This command is the same as "$g->pvresize" except that it allows
you to specify the new size (in bytes) explicitly.
@physvols = $g->pvs ();
List all the physical volumes detected. This is the equivalent of
the pvs(8) command.
This returns a list of just the device names that contain PVs (eg.
"/dev/sda2").
See also "$g->pvs_full".
@physvols = $g->pvs_full ();
List all the physical volumes detected. This is the equivalent of
the pvs(8) command. The "full" version includes all fields.
$uuid = $g->pvuuid ($device);
This command returns the UUID of the LVM PV "device".
$nbytes = $g->pwrite ($path, $content, $offset);
This command writes to part of a file. It writes the data buffer
"content" to the file "path" starting at offset "offset".
This command implements the pwrite(2) system call, and like that
system call it may not write the full data requested. The return
value is the number of bytes that were actually written to the
file. This could even be 0, although short writes are unlikely for
regular files in ordinary circumstances.
See also "$g->pread", "$g->pwrite_device".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$nbytes = $g->pwrite_device ($device, $content, $offset);
This command writes to part of a device. It writes the data buffer
"content" to "device" starting at offset "offset".
This command implements the pwrite(2) system call, and like that
system call it may not write the full data requested (although
short writes to disk devices and partitions are probably impossible
with standard Linux kernels).
See also "$g->pwrite".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$content = $g->read_file ($path);
This calls returns the contents of the file "path" as a buffer.
Unlike "$g->cat", this function can correctly handle files that
contain embedded ASCII NUL characters. However unlike
"$g->download", this function is limited in the total size of file
that can be handled.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->read_lines ($path);
Return the contents of the file named "path".
The file contents are returned as a list of lines. Trailing "LF"
and "CRLF" character sequences are not returned.
Note that this function cannot correctly handle binary files
(specifically, files containing "\0" character which is treated as
end of line). For those you need to use the "$g->read_file"
function which has a more complex interface.
@entries = $g->readdir ($dir);
This returns the list of directory entries in directory "dir".
All entries in the directory are returned, including "." and "..".
The entries are not sorted, but returned in the same order as the
underlying filesystem.
Also this call returns basic file type information about each file.
The "ftyp" field will contain one of the following characters:
'b' Block special
'c' Char special
'd' Directory
'f' FIFO (named pipe)
'l' Symbolic link
'r' Regular file
's' Socket
'u' Unknown file type
'?' The readdir(3) call returned a "d_type" field with an
unexpected value
This function is primarily intended for use by programs. To get a
simple list of names, use "$g->ls". To get a printable directory
for human consumption, use "$g->ll".
$link = $g->readlink ($path);
This command reads the target of a symbolic link.
@links = $g->readlinklist ($path, \@names);
This call allows you to do a "readlink" operation on multiple
files, where all files are in the directory "path". "names" is the
list of files from this directory.
On return you get a list of strings, with a one-to-one
correspondence to the "names" list. Each string is the value of
the symbolic link.
If the readlink(2) operation fails on any name, then the
corresponding result string is the empty string "". However the
whole operation is completed even if there were readlink(2) errors,
and so you can call this function with names where you don't know
if they are symbolic links already (albeit slightly less
efficient).
This call is intended for programs that want to efficiently list a
directory contents without making many round-trips. Very long
directory listings might cause the protocol message size to be
exceeded, causing this call to fail. The caller must split up such
requests into smaller groups of names.
$rpath = $g->realpath ($path);
Return the canonicalized absolute pathname of "path". The returned
path has no ".", ".." or symbolic link path elements.
$g->removexattr ($xattr, $path);
This call removes the extended attribute named "xattr" of the file
"path".
See also: "$g->lremovexattr", attr(5).
$g->resize2fs ($device);
This resizes an ext2, ext3 or ext4 filesystem to match the size of
the underlying device.
Note: It is sometimes required that you run "$g->e2fsck_f" on the
"device" before calling this command. For unknown reasons
"resize2fs" sometimes gives an error about this and sometimes not.
In any case, it is always safe to call "$g->e2fsck_f" before
calling this function.
$g->resize2fs_M ($device);
This command is the same as "$g->resize2fs", but the filesystem is
resized to its minimum size. This works like the -M option to the
"resize2fs" command.
To get the resulting size of the filesystem you should call
"$g->tune2fs_l" and read the "Block size" and "Block count" values.
These two numbers, multiplied together, give the resulting size of
the minimal filesystem in bytes.
$g->resize2fs_size ($device, $size);
This command is the same as "$g->resize2fs" except that it allows
you to specify the new size (in bytes) explicitly.
$g->rm ($path);
Remove the single file "path".
$g->rm_rf ($path);
Remove the file or directory "path", recursively removing the
contents if its a directory. This is like the "rm -rf" shell
command.
$g->rmdir ($path);
Remove the single directory "path".
$g->rmmountpoint ($exemptpath);
This calls removes a mountpoint that was previously created with
"$g->mkmountpoint". See "$g->mkmountpoint" for full details.
$g->scrub_device ($device);
This command writes patterns over "device" to make data retrieval
more difficult.
It is an interface to the scrub(1) program. See that manual page
for more details.
$g->scrub_file ($file);
This command writes patterns over a file to make data retrieval
more difficult.
The file is removed after scrubbing.
It is an interface to the scrub(1) program. See that manual page
for more details.
$g->scrub_freespace ($dir);
This command creates the directory "dir" and then fills it with
files until the filesystem is full, and scrubs the files as for
"$g->scrub_file", and deletes them. The intention is to scrub any
free space on the partition containing "dir".
It is an interface to the scrub(1) program. See that manual page
for more details.
$g->set_append ($append);
This function is used to add additional options to the guest kernel
command line.
The default is "NULL" unless overridden by setting
"LIBGUESTFS_APPEND" environment variable.
Setting "append" to "NULL" means no additional options are passed
(libguestfs always adds a few of its own).
$g->set_attach_method ($attachmethod);
Set the method that libguestfs uses to connect to the back end
guestfsd daemon. Possible methods are:
"appliance"
Launch an appliance and connect to it. This is the ordinary
method and the default.
"unix:path"
Connect to the Unix domain socket path.
This method lets you connect to an existing daemon or (using
virtio-serial) to a live guest. For more information, see
"ATTACHING TO RUNNING DAEMONS" in guestfs(3).
$g->set_autosync ($autosync);
If "autosync" is true, this enables autosync. Libguestfs will make
a best effort attempt to make filesystems consistent and
synchronized when the handle is closed (also if the program exits
without closing handles).
This is enabled by default (since libguestfs 1.5.24, previously it
was disabled by default).
$g->set_direct ($direct);
If the direct appliance mode flag is enabled, then stdin and stdout
are passed directly through to the appliance once it is launched.
One consequence of this is that log messages aren't caught by the
library and handled by "$g->set_log_message_callback", but go
straight to stdout.
You probably don't want to use this unless you know what you are
doing.
The default is disabled.
$g->set_e2label ($device, $label);
This sets the ext2/3/4 filesystem label of the filesystem on
"device" to "label". Filesystem labels are limited to 16
characters.
You can use either "$g->tune2fs_l" or "$g->get_e2label" to return
the existing label on a filesystem.
$g->set_e2uuid ($device, $uuid);
This sets the ext2/3/4 filesystem UUID of the filesystem on
"device" to "uuid". The format of the UUID and alternatives such
as "clear", "random" and "time" are described in the tune2fs(8)
manpage.
You can use either "$g->tune2fs_l" or "$g->get_e2uuid" to return
the existing UUID of a filesystem.
$g->set_memsize ($memsize);
This sets the memory size in megabytes allocated to the qemu
subprocess. This only has any effect if called before
"$g->launch".
You can also change this by setting the environment variable
"LIBGUESTFS_MEMSIZE" before the handle is created.
For more information on the architecture of libguestfs, see
guestfs(3).
$g->set_network ($network);
If "network" is true, then the network is enabled in the libguestfs
appliance. The default is false.
This affects whether commands are able to access the network (see
"RUNNING COMMANDS" in guestfs(3)).
You must call this before calling "$g->launch", otherwise it has no
effect.
$g->set_path ($searchpath);
Set the path that libguestfs searches for kernel and initrd.img.
The default is "$libdir/guestfs" unless overridden by setting
"LIBGUESTFS_PATH" environment variable.
Setting "path" to "NULL" restores the default path.
$g->set_pgroup ($pgroup);
If "pgroup" is true, child processes are placed into their own
process group.
The practical upshot of this is that signals like "SIGINT" (from
users pressing "^C") won't be received by the child process.
The default for this flag is false, because usually you want "^C"
to kill the subprocess. Guestfish sets this flag to true when used
interactively, so that "^C" can cancel long-running commands
gracefully (see "$g->user_cancel").
$g->set_qemu ($qemu);
Set the qemu binary that we will use.
The default is chosen when the library was compiled by the
configure script.
You can also override this by setting the "LIBGUESTFS_QEMU"
environment variable.
Setting "qemu" to "NULL" restores the default qemu binary.
Note that you should call this function as early as possible after
creating the handle. This is because some pre-launch operations
depend on testing qemu features (by running "qemu -help"). If the
qemu binary changes, we don't retest features, and so you might see
inconsistent results. Using the environment variable
"LIBGUESTFS_QEMU" is safest of all since that picks the qemu binary
at the same time as the handle is created.
$g->set_recovery_proc ($recoveryproc);
If this is called with the parameter "false" then "$g->launch" does
not create a recovery process. The purpose of the recovery process
is to stop runaway qemu processes in the case where the main
program aborts abruptly.
This only has any effect if called before "$g->launch", and the
default is true.
About the only time when you would want to disable this is if the
main process will fork itself into the background ("daemonize"
itself). In this case the recovery process thinks that the main
program has disappeared and so kills qemu, which is not very
helpful.
$g->set_selinux ($selinux);
This sets the selinux flag that is passed to the appliance at boot
time. The default is "selinux=0" (disabled).
Note that if SELinux is enabled, it is always in Permissive mode
("enforcing=0").
For more information on the architecture of libguestfs, see
guestfs(3).
$g->set_smp ($smp);
Change the number of virtual CPUs assigned to the appliance. The
default is 1. Increasing this may improve performance, though
often it has no effect.
This function must be called before "$g->launch".
$g->set_trace ($trace);
If the command trace flag is set to 1, then libguestfs calls,
parameters and return values are traced.
If you want to trace C API calls into libguestfs (and other
libraries) then possibly a better way is to use the external
ltrace(1) command.
Command traces are disabled unless the environment variable
"LIBGUESTFS_TRACE" is defined and set to 1.
Trace messages are normally sent to "stderr", unless you register a
callback to send them somewhere else (see
"$g->set_event_callback").
$g->set_verbose ($verbose);
If "verbose" is true, this turns on verbose messages.
Verbose messages are disabled unless the environment variable
"LIBGUESTFS_DEBUG" is defined and set to 1.
Verbose messages are normally sent to "stderr", unless you register
a callback to send them somewhere else (see
"$g->set_event_callback").
$g->setcon ($context);
This sets the SELinux security context of the daemon to the string
"context".
See the documentation about SELINUX in guestfs(3).
$g->setxattr ($xattr, $val, $vallen, $path);
This call sets the extended attribute named "xattr" of the file
"path" to the value "val" (of length "vallen"). The value is
arbitrary 8 bit data.
See also: "$g->lsetxattr", attr(5).
$g->sfdisk ($device, $cyls, $heads, $sectors, \@lines);
This is a direct interface to the sfdisk(8) program for creating
partitions on block devices.
"device" should be a block device, for example "/dev/sda".
"cyls", "heads" and "sectors" are the number of cylinders, heads
and sectors on the device, which are passed directly to sfdisk as
the -C, -H and -S parameters. If you pass 0 for any of these, then
the corresponding parameter is omitted. Usually for 'large' disks,
you can just pass 0 for these, but for small (floppy-sized) disks,
sfdisk (or rather, the kernel) cannot work out the right geometry
and you will need to tell it.
"lines" is a list of lines that we feed to "sfdisk". For more
information refer to the sfdisk(8) manpage.
To create a single partition occupying the whole disk, you would
pass "lines" as a single element list, when the single element
being the string "," (comma).
See also: "$g->sfdisk_l", "$g->sfdisk_N", "$g->part_init"
This function is deprecated. In new code, use the "part_add" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->sfdiskM ($device, \@lines);
This is a simplified interface to the "$g->sfdisk" command, where
partition sizes are specified in megabytes only (rounded to the
nearest cylinder) and you don't need to specify the cyls, heads and
sectors parameters which were rarely if ever used anyway.
See also: "$g->sfdisk", the sfdisk(8) manpage and "$g->part_disk"
This function is deprecated. In new code, use the "part_add" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$g->sfdisk_N ($device, $partnum, $cyls, $heads, $sectors, $line);
This runs sfdisk(8) option to modify just the single partition "n"
(note: "n" counts from 1).
For other parameters, see "$g->sfdisk". You should usually pass 0
for the cyls/heads/sectors parameters.
See also: "$g->part_add"
This function is deprecated. In new code, use the "part_add" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$partitions = $g->sfdisk_disk_geometry ($device);
This displays the disk geometry of "device" read from the partition
table. Especially in the case where the underlying block device
has been resized, this can be different from the kernel's idea of
the geometry (see "$g->sfdisk_kernel_geometry").
The result is in human-readable format, and not designed to be
parsed.
$partitions = $g->sfdisk_kernel_geometry ($device);
This displays the kernel's idea of the geometry of "device".
The result is in human-readable format, and not designed to be
parsed.
$partitions = $g->sfdisk_l ($device);
This displays the partition table on "device", in the human-
readable output of the sfdisk(8) command. It is not intended to be
parsed.
See also: "$g->part_list"
This function is deprecated. In new code, use the "part_list" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$output = $g->sh ($command);
This call runs a command from the guest filesystem via the guest's
"/bin/sh".
This is like "$g->command", but passes the command to:
/bin/sh -c "command"
Depending on the guest's shell, this usually results in wildcards
being expanded, shell expressions being interpolated and so on.
All the provisos about "$g->command" apply to this call.
@lines = $g->sh_lines ($command);
This is the same as "$g->sh", but splits the result into a list of
lines.
See also: "$g->command_lines"
$g->shutdown ();
This is the opposite of "$g->launch". It performs an orderly
shutdown of the backend process(es). If the autosync flag is set
(which is the default) then the disk image is synchronized.
If the subprocess exits with an error then this function will
return an error, which should not be ignored (it may indicate that
the disk image could not be written out properly).
It is safe to call this multiple times. Extra calls are ignored.
This call does not close or free up the handle. You still need to
call "$g->close" afterwards.
"$g->close" will call this if you don't do it explicitly, but note
that any errors are ignored in that case.
$g->sleep ($secs);
Sleep for "secs" seconds.
%statbuf = $g->stat ($path);
Returns file information for the given "path".
This is the same as the stat(2) system call.
%statbuf = $g->statvfs ($path);
Returns file system statistics for any mounted file system. "path"
should be a file or directory in the mounted file system (typically
it is the mount point itself, but it doesn't need to be).
This is the same as the statvfs(2) system call.
@stringsout = $g->strings ($path);
This runs the strings(1) command on a file and returns the list of
printable strings found.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@stringsout = $g->strings_e ($encoding, $path);
This is like the "$g->strings" command, but allows you to specify
the encoding of strings that are looked for in the source file
"path".
Allowed encodings are:
s Single 7-bit-byte characters like ASCII and the ASCII-
compatible parts of ISO-8859-X (this is what "$g->strings"
uses).
S Single 8-bit-byte characters.
b 16-bit big endian strings such as those encoded in UTF-16BE or
UCS-2BE.
l (lower case letter L)
16-bit little endian such as UTF-16LE and UCS-2LE. This is
useful for examining binaries in Windows guests.
B 32-bit big endian such as UCS-4BE.
L 32-bit little endian such as UCS-4LE.
The returned strings are transcoded to UTF-8.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->swapoff_device ($device);
This command disables the libguestfs appliance swap device or
partition named "device". See "$g->swapon_device".
$g->swapoff_file ($file);
This command disables the libguestfs appliance swap on file.
$g->swapoff_label ($label);
This command disables the libguestfs appliance swap on labeled swap
partition.
$g->swapoff_uuid ($uuid);
This command disables the libguestfs appliance swap partition with
the given UUID.
$g->swapon_device ($device);
This command enables the libguestfs appliance to use the swap
device or partition named "device". The increased memory is made
available for all commands, for example those run using
"$g->command" or "$g->sh".
Note that you should not swap to existing guest swap partitions
unless you know what you are doing. They may contain hibernation
information, or other information that the guest doesn't want you
to trash. You also risk leaking information about the host to the
guest this way. Instead, attach a new host device to the guest and
swap on that.
$g->swapon_file ($file);
This command enables swap to a file. See "$g->swapon_device" for
other notes.
$g->swapon_label ($label);
This command enables swap to a labeled swap partition. See
"$g->swapon_device" for other notes.
$g->swapon_uuid ($uuid);
This command enables swap to a swap partition with the given UUID.
See "$g->swapon_device" for other notes.
$g->sync ();
This syncs the disk, so that any writes are flushed through to the
underlying disk image.
You should always call this if you have modified a disk image,
before closing the handle.
@lines = $g->tail ($path);
This command returns up to the last 10 lines of a file as a list of
strings.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->tail_n ($nrlines, $path);
If the parameter "nrlines" is a positive number, this returns the
last "nrlines" lines of the file "path".
If the parameter "nrlines" is a negative number, this returns lines
from the file "path", starting with the "-nrlines"th line.
If the parameter "nrlines" is zero, this returns an empty list.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->tar_in ($tarfile, $directory);
This command uploads and unpacks local file "tarfile" (an
uncompressed tar file) into "directory".
To upload a compressed tarball, use "$g->tgz_in" or "$g->txz_in".
$g->tar_out ($directory, $tarfile);
This command packs the contents of "directory" and downloads it to
local file "tarfile".
To download a compressed tarball, use "$g->tgz_out" or
"$g->txz_out".
$g->tgz_in ($tarball, $directory);
This command uploads and unpacks local file "tarball" (a gzip
compressed tar file) into "directory".
To upload an uncompressed tarball, use "$g->tar_in".
$g->tgz_out ($directory, $tarball);
This command packs the contents of "directory" and downloads it to
local file "tarball".
To download an uncompressed tarball, use "$g->tar_out".
$g->touch ($path);
Touch acts like the touch(1) command. It can be used to update the
timestamps on a file, or, if the file does not exist, to create a
new zero-length file.
This command only works on regular files, and will fail on other
file types such as directories, symbolic links, block special etc.
$g->truncate ($path);
This command truncates "path" to a zero-length file. The file must
exist already.
$g->truncate_size ($path, $size);
This command truncates "path" to size "size" bytes. The file must
exist already.
If the current file size is less than "size" then the file is
extended to the required size with zero bytes. This creates a
sparse file (ie. disk blocks are not allocated for the file until
you write to it). To create a non-sparse file of zeroes, use
"$g->fallocate64" instead.
$g->tune2fs ($device [, force => $force] [, maxmountcount =>
$maxmountcount] [, mountcount => $mountcount] [, errorbehavior =>
$errorbehavior] [, group => $group] [, intervalbetweenchecks =>
$intervalbetweenchecks] [, reservedblockspercentage =>
$reservedblockspercentage] [, lastmounteddirectory =>
$lastmounteddirectory] [, reservedblockscount => $reservedblockscount]
[, user => $user]);
This call allows you to adjust various filesystem parameters of an
ext2/ext3/ext4 filesystem called "device".
The optional parameters are:
"force"
Force tune2fs to complete the operation even in the face of
errors. This is the same as the tune2fs "-f" option.
"maxmountcount"
Set the number of mounts after which the filesystem is checked
by e2fsck(8). If this is 0 then the number of mounts is
disregarded. This is the same as the tune2fs "-c" option.
"mountcount"
Set the number of times the filesystem has been mounted. This
is the same as the tune2fs "-C" option.
"errorbehavior"
Change the behavior of the kernel code when errors are
detected. Possible values currently are: "continue",
"remount-ro", "panic". In practice these options don't really
make any difference, particularly for write errors.
This is the same as the tune2fs "-e" option.
"group"
Set the group which can use reserved filesystem blocks. This
is the same as the tune2fs "-g" option except that it can only
be specified as a number.
"intervalbetweenchecks"
Adjust the maximal time between two filesystem checks (in
seconds). If the option is passed as 0 then time-dependent
checking is disabled.
This is the same as the tune2fs "-i" option.
"reservedblockspercentage"
Set the percentage of the filesystem which may only be
allocated by privileged processes. This is the same as the
tune2fs "-m" option.
"lastmounteddirectory"
Set the last mounted directory. This is the same as the
tune2fs "-M" option.
"reservedblockscount" Set the number of reserved filesystem blocks.
This is the same as the tune2fs "-r" option.
"user"
Set the user who can use the reserved filesystem blocks. This
is the same as the tune2fs "-u" option except that it can only
be specified as a number.
To get the current values of filesystem parameters, see
"$g->tune2fs_l". For precise details of how tune2fs works, see the
tune2fs(8) man page.
%superblock = $g->tune2fs_l ($device);
This returns the contents of the ext2, ext3 or ext4 filesystem
superblock on "device".
It is the same as running "tune2fs -l device". See tune2fs(8)
manpage for more details. The list of fields returned isn't
clearly defined, and depends on both the version of "tune2fs" that
libguestfs was built against, and the filesystem itself.
$g->txz_in ($tarball, $directory);
This command uploads and unpacks local file "tarball" (an xz
compressed tar file) into "directory".
$g->txz_out ($directory, $tarball);
This command packs the contents of "directory" and downloads it to
local file "tarball" (as an xz compressed tar archive).
$oldmask = $g->umask ($mask);
This function sets the mask used for creating new files and device
nodes to "mask & 0777".
Typical umask values would be 022 which creates new files with
permissions like "-rw-r--r--" or "-rwxr-xr-x", and 002 which
creates new files with permissions like "-rw-rw-r--" or
"-rwxrwxr-x".
The default umask is 022. This is important because it means that
directories and device nodes will be created with 0644 or 0755 mode
even if you specify 0777.
See also "$g->get_umask", umask(2), "$g->mknod", "$g->mkdir".
This call returns the previous umask.
$g->umount ($pathordevice);
This unmounts the given filesystem. The filesystem may be
specified either by its mountpoint (path) or the device which
contains the filesystem.
$g->umount_all ();
This unmounts all mounted filesystems.
Some internal mounts are not unmounted by this call.
$g->upload ($filename, $remotefilename);
Upload local file "filename" to "remotefilename" on the filesystem.
"filename" can also be a named pipe.
See also "$g->download".
$g->upload_offset ($filename, $remotefilename, $offset);
Upload local file "filename" to "remotefilename" on the filesystem.
"remotefilename" is overwritten starting at the byte "offset"
specified. The intention is to overwrite parts of existing files
or devices, although if a non-existant file is specified then it is
created with a "hole" before "offset". The size of the data
written is implicit in the size of the source "filename".
Note that there is no limit on the amount of data that can be
uploaded with this call, unlike with "$g->pwrite", and this call
always writes the full amount unless an error occurs.
See also "$g->upload", "$g->pwrite".
$g->utimens ($path, $atsecs, $atnsecs, $mtsecs, $mtnsecs);
This command sets the timestamps of a file with nanosecond
precision.
"atsecs, atnsecs" are the last access time (atime) in secs and
nanoseconds from the epoch.
"mtsecs, mtnsecs" are the last modification time (mtime) in secs
and nanoseconds from the epoch.
If the *nsecs field contains the special value "-1" then the
corresponding timestamp is set to the current time. (The *secs
field is ignored in this case).
If the *nsecs field contains the special value "-2" then the
corresponding timestamp is left unchanged. (The *secs field is
ignored in this case).
%version = $g->version ();
Return the libguestfs version number that the program is linked
against.
Note that because of dynamic linking this is not necessarily the
version of libguestfs that you compiled against. You can compile
the program, and then at runtime dynamically link against a
completely different "libguestfs.so" library.
This call was added in version 1.0.58. In previous versions of
libguestfs there was no way to get the version number. From C code
you can use dynamic linker functions to find out if this symbol
exists (if it doesn't, then it's an earlier version).
The call returns a structure with four elements. The first three
("major", "minor" and "release") are numbers and correspond to the
usual version triplet. The fourth element ("extra") is a string
and is normally empty, but may be used for distro-specific
information.
To construct the original version string:
"$major.$minor.$release$extra"
See also: "LIBGUESTFS VERSION NUMBERS" in guestfs(3).
Note: Don't use this call to test for availability of features. In
enterprise distributions we backport features from later versions
into earlier versions, making this an unreliable way to test for
features. Use "$g->available" instead.
$label = $g->vfs_label ($device);
This returns the filesystem label of the filesystem on "device".
If the filesystem is unlabeled, this returns the empty string.
To find a filesystem from the label, use "$g->findfs_label".
$fstype = $g->vfs_type ($device);
This command gets the filesystem type corresponding to the
filesystem on "device".
For most filesystems, the result is the name of the Linux VFS
module which would be used to mount this filesystem if you mounted
it without specifying the filesystem type. For example a string
such as "ext3" or "ntfs".
$uuid = $g->vfs_uuid ($device);
This returns the filesystem UUID of the filesystem on "device".
If the filesystem does not have a UUID, this returns the empty
string.
To find a filesystem from the UUID, use "$g->findfs_uuid".
$g->vg_activate ($activate, \@volgroups);
This command activates or (if "activate" is false) deactivates all
logical volumes in the listed volume groups "volgroups".
This command is the same as running "vgchange -a y|n volgroups..."
Note that if "volgroups" is an empty list then all volume groups
are activated or deactivated.
$g->vg_activate_all ($activate);
This command activates or (if "activate" is false) deactivates all
logical volumes in all volume groups.
This command is the same as running "vgchange -a y|n"
$g->vgcreate ($volgroup, \@physvols);
This creates an LVM volume group called "volgroup" from the non-
empty list of physical volumes "physvols".
@uuids = $g->vglvuuids ($vgname);
Given a VG called "vgname", this returns the UUIDs of all the
logical volumes created in this volume group.
You can use this along with "$g->lvs" and "$g->lvuuid" calls to
associate logical volumes and volume groups.
See also "$g->vgpvuuids".
@uuids = $g->vgpvuuids ($vgname);
Given a VG called "vgname", this returns the UUIDs of all the
physical volumes that this volume group resides on.
You can use this along with "$g->pvs" and "$g->pvuuid" calls to
associate physical volumes and volume groups.
See also "$g->vglvuuids".
$g->vgremove ($vgname);
Remove an LVM volume group "vgname", (for example "VG").
This also forcibly removes all logical volumes in the volume group
(if any).
$g->vgrename ($volgroup, $newvolgroup);
Rename a volume group "volgroup" with the new name "newvolgroup".
@volgroups = $g->vgs ();
List all the volumes groups detected. This is the equivalent of
the vgs(8) command.
This returns a list of just the volume group names that were
detected (eg. "VolGroup00").
See also "$g->vgs_full".
@volgroups = $g->vgs_full ();
List all the volumes groups detected. This is the equivalent of
the vgs(8) command. The "full" version includes all fields.
$g->vgscan ();
This rescans all block devices and rebuilds the list of LVM
physical volumes, volume groups and logical volumes.
$uuid = $g->vguuid ($vgname);
This command returns the UUID of the LVM VG named "vgname".
$g->wait_ready ();
This function is a no op.
In versions of the API < 1.0.71 you had to call this function just
after calling "$g->launch" to wait for the launch to complete.
However this is no longer necessary because "$g->launch" now does
the waiting.
If you see any calls to this function in code then you can just
remove them, unless you want to retain compatibility with older
versions of the API.
This function is deprecated. In new code, use the "launch" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
$chars = $g->wc_c ($path);
This command counts the characters in a file, using the "wc -c"
external command.
$lines = $g->wc_l ($path);
This command counts the lines in a file, using the "wc -l" external
command.
$words = $g->wc_w ($path);
This command counts the words in a file, using the "wc -w" external
command.
$g->write ($path, $content);
This call creates a file called "path". The content of the file is
the string "content" (which can contain any 8 bit data).
See also "$g->write_append".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->write_append ($path, $content);
This call appends "content" to the end of file "path". If "path"
does not exist, then a new file is created.
See also "$g->write".
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->write_file ($path, $content, $size);
This call creates a file called "path". The contents of the file
is the string "content" (which can contain any 8 bit data), with
length "size".
As a special case, if "size" is 0 then the length is calculated
using "strlen" (so in this case the content cannot contain embedded
ASCII NULs).
NB. Owing to a bug, writing content containing ASCII NUL characters
does not work, even if the length is specified.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
This function is deprecated. In new code, use the "write" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
@lines = $g->zegrep ($regex, $path);
This calls the external "zegrep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->zegrepi ($regex, $path);
This calls the external "zegrep -i" program and returns the
matching lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$g->zero ($device);
This command writes zeroes over the first few blocks of "device".
How many blocks are zeroed isn't specified (but it's not enough to
securely wipe the device). It should be sufficient to remove any
partition tables, filesystem superblocks and so on.
If blocks are already zero, then this command avoids writing
zeroes. This prevents the underlying device from becoming non-
sparse or growing unnecessarily.
See also: "$g->zero_device", "$g->scrub_device",
"$g->is_zero_device"
$g->zero_device ($device);
This command writes zeroes over the entire "device". Compare with
"$g->zero" which just zeroes the first few blocks of a device.
If blocks are already zero, then this command avoids writing
zeroes. This prevents the underlying device from becoming non-
sparse or growing unnecessarily.
$g->zerofree ($device);
This runs the zerofree program on "device". This program claims to
zero unused inodes and disk blocks on an ext2/3 filesystem, thus
making it possible to compress the filesystem more effectively.
You should not run this program if the filesystem is mounted.
It is possible that using this program can damage the filesystem or
data on the filesystem.
@lines = $g->zfgrep ($pattern, $path);
This calls the external "zfgrep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->zfgrepi ($pattern, $path);
This calls the external "zfgrep -i" program and returns the
matching lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
$description = $g->zfile ($meth, $path);
This command runs "file" after first decompressing "path" using
"method".
"method" must be one of "gzip", "compress" or "bzip2".
Since 1.0.63, use "$g->file" instead which can now process
compressed files.
This function is deprecated. In new code, use the "file" call
instead.
Deprecated functions will not be removed from the API, but the fact
that they are deprecated indicates that there are problems with
correct use of these functions.
@lines = $g->zgrep ($regex, $path);
This calls the external "zgrep" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
@lines = $g->zgrepi ($regex, $path);
This calls the external "zgrep -i" program and returns the matching
lines.
Because of the message protocol, there is a transfer limit of
somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
AVAILABILITY
From time to time we add new libguestfs APIs. Also some libguestfs
APIs won't be available in all builds of libguestfs (the Fedora build
is full-featured, but other builds may disable features). How do you
test whether the APIs that your Perl program needs are available in the
version of "Sys::Guestfs" that you are using?
To test if a particular function is available in the "Sys::Guestfs"
class, use the ordinary Perl UNIVERSAL method "can(METHOD)" (see
perlobj(1)). For example:
use Sys::Guestfs;
if (defined (Sys::Guestfs->can ("set_verbose"))) {
print "\$g->set_verbose is available\n";
}
Perl does not offer a way to list the arguments of a method, and from
time to time we may add extra arguments to calls that take optional
arguments. For this reason, we provide a global hash variable
%guestfs_introspection which contains the arguments and their types for
each libguestfs method. The keys of this hash are the method names,
and the values are an hashref containing useful introspection
information about the method (further fields may be added to this in
future).
use Sys::Guestfs;
$Sys::Guestfs::guestfs_introspection{mkfs_opts}
=> {
ret => 'void', # return type
args => [ # required arguments
[ 'fstype', 'string', 0 ],
[ 'device', 'string(device)', 1 ],
],
optargs => { # optional arguments
blocksize => [ 'blocksize', 'int', 0 ],
features => [ 'features', 'string', 1 ],
inode => [ 'inode', 'int', 2 ],
sectorsize => [ 'sectorsize', 'int', 3 ],
},
name => "mkfs_opts",
description => "make a filesystem",
}
To test if particular features are supported by the current build, use
the "available" method like the example below. Note that the appliance
must be launched first.
$g->available ( ["augeas"] );
Since the "available" method croaks if the feature is not supported,
you might also want to wrap this in an eval and return a boolean. In
fact this has already been done for you: use "feature_available" in
Sys::Guestfs::Lib(3).
For further discussion on this topic, refer to "AVAILABILITY" in
guestfs(3).
STORING DATA IN THE HANDLE
The handle returned from "new" is a hash reference. The hash normally
contains a single element:
{
_g => [private data used by libguestfs]
}
Callers can add other elements to this hash to store data for their own
purposes. The data lasts for the lifetime of the handle.
Any fields whose names begin with an underscore are reserved for
private use by libguestfs. We may add more in future.
It is recommended that callers prefix the name of their field(s) with
some unique string, to avoid conflicts with other users.
COPYRIGHT
Copyright (C) 2009-2012 Red Hat Inc.
LICENSE
Please see the file COPYING.LIB for the full license.
SEE ALSOguestfs(3), guestfish(1), <http://libguestfs.org>,
Sys::Guestfs::Lib(3).
perl v5.14.3 2012-11-22 Sys::Guestfs(3)
