VOP_CREATE(9) BSD Kernel Developer's Manual VOP_CREATE(9)NAME
VOP_CREATE, VOP_MKNOD, VOP_MKDIR, VOP_SYMLINK — create a file, socket,
fifo, device, directory or symlink
SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/namei.h>
int
VOP_CREATE(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct vattr *vap);
int
VOP_MKNOD(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct vattr *vap);
int
VOP_MKDIR(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct vattr *vap);
int
VOP_SYMLINK(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct vattr *vap, char *target);
DESCRIPTION
These entry points create a new file, socket, fifo, device, directory or
symlink in a given directory.
The arguments are:
dvp the locked vnode of the directory
vpp the address of a variable where the resulting locked vnode should
be stored
cnp the pathname component created
vap the attributes that the new object should be created with
target the pathname of the target of the symlink
These entry points are called after VOP_LOOKUP(9) when an object is being
created. Normally, VOP_LOOKUP(9) will have set the SAVENAME flag in
cnp->cn_flags to keep the memory pointed to by cnp->cn_pnbuf valid. If
an error is detected when creating the file, then this memory will be
freed. If the file is created successfully, then it will be freed unless
the SAVESTART flag is specified in cnp.
LOCKS
The directory, dvp will be locked on entry and must remain locked on
return. If the call is successful, the new object will be returned
locked.
RETURN VALUES
If successful, the vnode for the new object is placed in *vpp and zero is
returned. Otherwise, an appropriate error is returned.
PSEUDOCODE
int
vop_create(struct vnode *dvp,
struct vnode **vpp,
struct componentname *cnp
struct vattr *vap)
{
int mode = MAKEIMODE(vap->va_type, vap->va_mode);
struct vnode *vp;
int error;
*vpp = NULL;
if ((mode & IFMT) == 0)
mode |= IFREG;
error = SOMEFS_VALLOC(dvp, mode, cnp->cn_cred, &vp);
if (error) {
kfree(cnp->cn_pnbuf, M_NAMEI);
vput(dvp);
return error;
}
/*
* Update the permissions for the new vnode, including
* copying the group from the directory.
*/
...;
#ifdef QUOTA
/*
* Possibly check quota information.
*/
...;
#endif
/*
* Enter new vnode in directory, taking care that the vnode
* hits the disk before the directory contents are changed.
*/
error = ...;
if (error)
goto bad;
if ((cnp->cn_flags & SAVESTART) == 0)
kfree(cnp->cn_pnbuf, M_NAMEI);
vput(dvp);
*vpp = vp;
return 0;
bad:
/*
* Write error occurred trying to update the inode
* or the directory so must deallocate the inode.
*/
kfree(cnp->cn_pnbuf, M_NAMEI);
vput(vp);
/*
* Deallocate filesystem resources for vp.
*/
...;
vput(dvp);
return error;
}
ERRORS
[ENOSPC] The filesystem is full.
[EDQUOT] Quota exceeded.
SEE ALSOvnode(9), VOP_LOOKUP(9)HISTORY
The function VOP_CREATE appeared in 4.3BSD.
AUTHORS
This man page was written by Doug Rabson.
BSD July 24, 1996 BSD
