posix/spawn_faction_adddup2.c

   1 /* Copyright (C) 2000 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 <errno.h>
  20 #include <spawn.h>
  21 #include <unistd.h>
  22
  23 #include "spawn_int.h"
  24
  25 /* Add an action to FILE-ACTIONS which tells the implementation to call
  26    `dup2' for the given file descriptors during the `spawn' call.  */
  27 int
  28 posix_spawn_file_actions_adddup2 (posix_spawn_file_actions_t *file_actions,
  29                                   int fd, int newfd)
  30 {
  31   int maxfd = __sysconf (_SC_OPEN_MAX);
  32   struct __spawn_action *rec;
  33
  34   /* Test for the validity of the file descriptor.  */
  35   if (fd < 0 || newfd < 0 || fd >= maxfd || newfd >= maxfd)
  36     return EBADF;
  37
  38   /* Allocate more memory if needed.  */
  39   if (file_actions->__used == file_actions->__allocated
  40       && __posix_spawn_file_actions_realloc (file_actions) != 0)
  41     /* This can only mean we ran out of memory.  */
  42     return ENOMEM;
  43
  44   /* Add the new value.  */
  45   rec = &file_actions->__actions[file_actions->__used];
  46   rec->tag = spawn_do_dup2;
  47   rec->action.dup2_action.fd = fd;
  48   rec->action.dup2_action.newfd = newfd;
  49
  50   /* Account for the new entry.  */
  51   ++file_actions->__used;
  52
  53   return 0;
  54 }