posix/execl.c

   1 /* Copyright (C) 1991-2017 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <unistd.h>
  19 #include <errno.h>
  20 #include <stdarg.h>
  21 #include <sys/param.h>
  22
  23 /* Execute PATH with all arguments after PATH until
  24    a NULL pointer and environment from `environ'.  */
  25 int
  26 execl (const char *path, const char *arg, ...)
  27 {
  28   ptrdiff_t argc;
  29   va_list ap;
  30   va_start (ap, arg);
  31   for (argc = 1; va_arg (ap, const char *); argc++)
  32     {
  33       if (argc == INT_MAX)
  34         {
  35           va_end (ap);
  36           errno = E2BIG;
  37           return -1;
  38         }
  39     }
  40   va_end (ap);
  41
  42   /* Avoid dynamic memory allocation due two main issues:
  43      1. The function should be async-signal-safe and a running on a signal
  44         handler with a fail outcome might lead to malloc bad state.
  45      2. It might be used in a vfork/clone(VFORK) scenario where using
  46         malloc also might lead to internal bad state.  */
  47   ptrdiff_t i;
  48   char *argv[argc + 1];
  49   va_start (ap, arg);
  50   argv[0] = (char *) arg;
  51   for (i = 1; i <= argc; i++)
  52     argv[i] = va_arg (ap, char *);
  53   va_end (ap);
  54
  55   return __execve (path, argv, __environ);
  56 }
  57 libc_hidden_def (execl)