posix/execl.c

   1 /* Copyright (C) 1991,92,94,97,98,99,2002,2005 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <unistd.h>
  20 #include <stdarg.h>
  21 #include <stddef.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #include <stackinfo.h>
  26
  27 #ifndef HAVE_GNU_LD
  28 # define __environ      environ
  29 #endif
  30
  31 /* Execute PATH with all arguments after PATH until
  32    a NULL pointer and environment from `environ'.  */
  33 int
  34 execl (const char *path, const char *arg, ...)
  35 {
  36 #define INITIAL_ARGV_MAX 1024
  37   size_t argv_max = INITIAL_ARGV_MAX;
  38   const char *initial_argv[INITIAL_ARGV_MAX];
  39   const char **argv = initial_argv;
  40   va_list args;
  41
  42   argv[0] = arg;
  43
  44   va_start (args, arg);
  45   unsigned int i = 0;
  46   while (argv[i++] != NULL)
  47     {
  48       if (i == argv_max)
  49         {
  50           argv_max *= 2;
  51           const char **nptr = realloc (argv == initial_argv ? NULL : argv,
  52                                        argv_max * sizeof (const char *));
  53           if (nptr == NULL)
  54             {
  55               if (argv != initial_argv)
  56                 free (argv);
  57               return -1;
  58             }
  59           if (argv == initial_argv)
  60             /* We have to copy the already filled-in data ourselves.  */
  61             memcpy (nptr, argv, i * sizeof (const char *));
  62
  63           argv = nptr;
  64         }
  65
  66       argv[i] = va_arg (args, const char *);
  67     }
  68   va_end (args);
  69
  70   int ret = __execve (path, (char *const *) argv, __environ);
  71   if (argv != initial_argv)
  72     free (argv);
  73
  74   return ret;
  75 }
  76 libc_hidden_def (execl)