RUNIDN(1)RUNIDN(1)NAMErunidn - A script to allow applications to use internationalized domain
names.
SYNOPSISrunidn [-e local-codeset] program-name [args..]
DESCRIPTIONrunidn enables applications to use internationalized domain names with‐
out recompilation. Just add ``runidn'' before the application-name,
and the application can handle non-ASCII domain names. For example,
you can do:
% runidn telnet non-ASCII-hostname
Before using runidn, you should set up properties related to interna‐
tionalized DNS by configuring idnkit's configuration file idn.conf.
See idn.conf(5) which describes the configuration.
OPTION
The following option is available:
-e local-codeset
Specify the application's local codeset. If the option is not
specified, runidn guesses the codeset from the current locale. See
the ``NOTE'' section for more details about local codeset.
IMPLEMENTATIONrunidn is a small shell script that sets up an environment variable
called ``LD_PRELOAD'', so that an application dynamically links a
shared library ``libidnkitres'' before any other shared libraries.
The library ``libidnkitres'' provides a special version of resolver
functions which implement features for handling internationalized
domain names. runidn replaces the following functions with the special
version:
gethostbyname
gethostbyname2
gethostbyaddr
gethostbyname_r
gethostbyname2_r
gethostbyaddr_r
getipnodebyname
getipnodebyaddr
freehostent
getaddrinfo
freeaddrinfo
getnameinfo
By overriding them in the standard libraries with the special version
provided by ``libidnkitres'', runidn enables applications to use inter‐
nationalized domain names.
· These API functions accept non-ASCII domain names encoded in the
local codeset that the application is using. Also the result
from these APIs may contain non-ASCII domain names.
· The normalization and codeset conversion between application's
local codeset and the codeset used in DNS protocol data are han‐
dled automatically, so users/applications need not worry about
them.
Properties of internationalized DNS (such as the normalization or the
codeset used on DNS protocol data) can be configured with the idnkit's
configuration file (idn.conf). See idn.conf(5) for details.
NOTE
Unless -e option is specified, runidn tries to guess the application's
local codeset from the application's current locale. However, some‐
times it cannot guess the codeset correctly, for example if the appli‐
cation does not set the locale appropriately by calling `setlocale()'.
In that case, you can explicitly specify the local codeset by setting
an environment variable ``IDN_LOCAL_CODESET''. See the section ``LOCAL
CODESET'' in idn.conf(5) for details.
The idea of using ``LD_PRELOAD'' to replace some functions in the stan‐
dard library was taken from ``runsocks'' script distributed as part of
SOCKS5 reference implementation.
BUGS
There are many cases where runidn does not work.
Your system must support ``LD_PRELOAD'' mechanism in the first place.
Due to security reasons, ``LD_PRELOAD'' mechanism is disabled for
setuid programs in any sane systems. So runidn does not work for
setuid programs such as ping or rsh.
If your application uses a function other than the ones runidn supports
for name resolution, you lose.
SEE ALSOidn.conf(5), runsocks(1)
April 6, 2001 RUNIDN(1)
