posix/execlp.c

   1 /* Copyright (C) 1991,93,96,97,98,99,2002,2005 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 /* Execute FILE, searching in the `PATH' environment variable if
  28    it contains no slashes, with all arguments after FILE until a
  29    NULL pointer and environment from `environ'.  */
  30 int
  31 execlp (const char *file, const char *arg, ...)
  32 {
  33 #define INITIAL_ARGV_MAX 1024
  34   size_t argv_max = INITIAL_ARGV_MAX;
  35   const char *initial_argv[INITIAL_ARGV_MAX];
  36   const char **argv = initial_argv;
  37   va_list args;
  38
  39   argv[0] = arg;
  40
  41   va_start (args, arg);
  42   unsigned int i = 0;
  43   while (argv[i++] != NULL)
  44     {
  45       if (i == argv_max)
  46         {
  47           argv_max *= 2;
  48           const char **nptr = realloc (argv == initial_argv ? NULL : argv,
  49                                        argv_max * sizeof (const char *));
  50           if (nptr == NULL)
  51             {
  52               if (argv != initial_argv)
  53                 free (argv);
  54               return -1;
  55             }
  56           if (argv == initial_argv)
  57             /* We have to copy the already filled-in data ourselves.  */
  58             memcpy (nptr, argv, i * sizeof (const char *));
  59
  60           argv = nptr;
  61         }
  62
  63       argv[i] = va_arg (args, const char *);
  64     }
  65   va_end (args);
  66
  67   int ret = execvp (file, (char *const *) argv);
  68   if (argv != initial_argv)
  69     free (argv);
  70
  71   return ret;
  72 }
  73 libc_hidden_def (execlp)