posix/spawn_faction_adddup2.c

   1 /* Copyright (C) 2000-2015 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 <errno.h>
  19 #include <spawn.h>
  20 #include <unistd.h>
  21
  22 #include "spawn_int.h"
  23
  24 /* Add an action to FILE-ACTIONS which tells the implementation to call
  25    `dup2' for the given file descriptors during the `spawn' call.  */
  26 int
  27 posix_spawn_file_actions_adddup2 (posix_spawn_file_actions_t *file_actions,
  28                                   int fd, int newfd)
  29 {
  30   int maxfd = __sysconf (_SC_OPEN_MAX);
  31   struct __spawn_action *rec;
  32
  33   /* Test for the validity of the file descriptor.  */
  34   if (fd < 0 || newfd < 0 || fd >= maxfd || newfd >= maxfd)
  35     return EBADF;
  36
  37   /* Allocate more memory if needed.  */
  38   if (file_actions->__used == file_actions->__allocated
  39       && __posix_spawn_file_actions_realloc (file_actions) != 0)
  40     /* This can only mean we ran out of memory.  */
  41     return ENOMEM;
  42
  43   /* Add the new value.  */
  44   rec = &file_actions->__actions[file_actions->__used];
  45   rec->tag = spawn_do_dup2;
  46   rec->action.dup2_action.fd = fd;
  47   rec->action.dup2_action.newfd = newfd;
  48
  49   /* Account for the new entry.  */
  50   ++file_actions->__used;
  51
  52   return 0;
  53 }