glibc/posix/getopt_init.c

75 lines
2.7 KiB
C

/* Perform additional initialization for getopt functions in GNU libc.
Copyright (C) 1997-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifdef USE_NONOPTION_FLAGS
/* Attention: this file is *not* necessary when the GNU getopt functions
are used outside the GNU libc. Some additional functionality of the
getopt functions in GNU libc require this additional work. */
#include <getopt.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <_itoa.h>
/* Variable to synchronize work. */
char *__getopt_nonoption_flags;
/* Remove the environment variable "_<PID>_GNU_nonoption_argv_flags_" if
it is still available. If the getopt functions are also used in the
application it does not exist anymore since it was saved for the use
in getopt. */
void
__getopt_clean_environment (char **env)
{
/* Bash 2.0 puts a special variable in the environment for each
command it runs, specifying which ARGV elements are the results
of file name wildcard expansion and therefore should not be
considered as options. */
static const char envvar_tail[] = "_GNU_nonoption_argv_flags_=";
char var[50];
char *cp, **ep;
size_t len;
/* Construct the "_<PID>_GNU_nonoption_argv_flags_=" string. We must
not use `sprintf'. */
cp = memcpy (&var[sizeof (var) - sizeof (envvar_tail)], envvar_tail,
sizeof (envvar_tail));
cp = _itoa_word (__getpid (), cp, 10, 0);
/* Note: we omit adding the leading '_' since we explicitly test for
it before calling strncmp. */
len = (var + sizeof (var) - 1) - cp;
for (ep = env; *ep != NULL; ++ep)
if ((*ep)[0] == '_'
&& __builtin_expect (strncmp (*ep + 1, cp, len) == 0, 0))
{
/* Found it. Store this pointer and move later ones back. */
char **dp = ep;
__getopt_nonoption_flags = &(*ep)[len];
do
dp[0] = dp[1];
while (*dp++);
/* Continue the loop in case the name appears again. */
}
}
#endif /* USE_NONOPTION_FLAGS */