posix/execle.c

   1 /* Copyright (C) 1991-2021 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <unistd.h>
  19 #include <stdarg.h>
  20 #include <errno.h>
  21 #include <sys/param.h>
  22 #include <stddef.h>
  23
  24 /* Execute PATH with all arguments after PATH until a NULL pointer,
  25    and the argument after that for environment.  */
  26 int
  27 execle (const char *path, const char *arg, ...)
  28 {
  29   ptrdiff_t argc;
  30   va_list ap;
  31   va_start (ap, arg);
  32   for (argc = 1; va_arg (ap, const char *); argc++)
  33     {
  34       if (argc == INT_MAX)
  35         {
  36           va_end (ap);
  37           errno = E2BIG;
  38           return -1;
  39         }
  40     }
  41   va_end (ap);
  42
  43   /* Avoid dynamic memory allocation due two main issues:
  44      1. The function should be async-signal-safe and a running on a signal
  45         handler with a fail outcome might lead to malloc bad state.
  46      2. It might be used in a vfork/clone(VFORK) scenario where using
  47         malloc also might lead to internal bad state.  */
  48   ptrdiff_t i;
  49   char *argv[argc + 1];
  50   char **envp;
  51   va_start (ap, arg);
  52   argv[0] = (char *) arg;
  53   for (i = 1; i <= argc; i++)
  54     argv[i] = va_arg (ap, char *);
  55   envp = va_arg (ap, char **);
  56   va_end (ap);
  57
  58   return __execve (path, argv, envp);
  59 }
  60 libc_hidden_def (execle)