posix/getopt_init.c

   1 /* Perform additional initialization for getopt functions in GNU libc.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 /* Attention: this file is *not* necessary when the GNU getopt functions
  22    are used outside the GNU libc.  Some additional functionality of the
  23    getopt functions in GNU libc require this additional work.  */
  24
  25 #include <getopt.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <sys/types.h>
  29
  30 #include "../stdio-common/_itoa.h"
  31
  32 /* External variable to synchronize work.  */
  33 extern char *__getopt_nonoption_flags;
  34
  35 extern pid_t __libc_pid;
  36
  37
  38 /* Remove the environment variable "_<PID>_GNU_nonoption_argv_flags_" if
  39    it is still available.  If the getopt functions are also used in the
  40    application it does not exist anymore since it was saved for the use
  41    in getopt.  */
  42 void
  43 __getopt_clean_environment (void)
  44 {
  45   /* Bash 2.0 puts a special variable in the environment for each
  46      command it runs, specifying which ARGV elements are the results
  47      of file name wildcard expansion and therefore should not be
  48      considered as options.  */
  49   static const char envvar_tail[] = "_GNU_nonoption_argv_flags_";
  50   char var[100];
  51   char *cp, **ep;
  52   size_t len;
  53
  54   /* Generate name of the environment variable.  We must know the PID
  55      and we must not use `sprintf'.  */
  56   if (__libc_pid == 0)
  57     __libc_pid = getpid ();
  58
  59   /* Construct "_<PID>_GNU_nonoption_argv_flags_" string.  */
  60   cp = memcpy (&var[sizeof (var) - sizeof (envvar_tail)], envvar_tail,
  61                sizeof (envvar_tail));
  62   cp = _itoa_word (__libc_pid, cp, 10, 0);
  63   *--cp = '_';
  64   len = (var + sizeof (var) - 1) - cp;
  65
  66   for (ep = __environ; *ep != NULL; ++ep)
  67     if (!strncmp (*ep, cp, len) && (*ep)[len] == '=')
  68       {
  69         /* Found it.  Store this pointer and move later ones back.  */
  70         char **dp = ep;
  71         __getopt_nonoption_flags = &(*ep)[len + 1];
  72         do
  73           dp[0] = dp[1];
  74         while (*dp++);
  75         /* Continue the loop in case the name appears again.  */
  76       }
  77 }