lib/spawn_faction_addfchdir.c

   1 /* Copyright (C) 2018-2024 Free Software Foundation, Inc.
   2
   3    This file is free software: you can redistribute it and/or modify
   4    it under the terms of the GNU Lesser General Public License as
   5    published by the Free Software Foundation; either version 2.1 of the
   6    License, or (at your option) any later version.
   7
   8    This file is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU Lesser General Public License for more details.
  12
  13    You should have received a copy of the GNU Lesser General Public License
  14    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  15
  16 #include <config.h>
  17
  18 /* Specification.  */
  19 #include <spawn.h>
  20
  21 #include <errno.h>
  22 #include <unistd.h>
  23
  24 #if !_LIBC
  25 # define __sysconf(open_max) getdtablesize ()
  26 #endif
  27
  28 #if REPLACE_POSIX_SPAWN
  29 # include "spawn_int.h"
  30 #endif
  31
  32 /* Add an action to FILE-ACTIONS which tells the implementation to call
  33    'fchdir' to the given directory during the 'spawn' call.  */
  34 int
  35 posix_spawn_file_actions_addfchdir (posix_spawn_file_actions_t *file_actions,
  36                                     int fd)
  37 #undef posix_spawn_file_actions_addfchdir
  38 {
  39   int maxfd = __sysconf (_SC_OPEN_MAX);
  40
  41   /* Test for the validity of the file descriptor.  */
  42   if (fd < 0 || fd >= maxfd)
  43     return EBADF;
  44
  45 #if !REPLACE_POSIX_SPAWN
  46   return posix_spawn_file_actions_addfchdir_np (file_actions, fd);
  47 #else
  48   /* Allocate more memory if needed.  */
  49   if (file_actions->_used == file_actions->_allocated
  50       && __posix_spawn_file_actions_realloc (file_actions) != 0)
  51     /* This can only mean we ran out of memory.  */
  52     return ENOMEM;
  53
  54   {
  55     struct __spawn_action *rec;
  56
  57     /* Add the new value.  */
  58     rec = &file_actions->_actions[file_actions->_used];
  59     rec->tag = spawn_do_fchdir;
  60     rec->action.fchdir_action.fd = fd;
  61
  62     /* Account for the new entry.  */
  63     ++file_actions->_used;
  64
  65     return 0;
  66   }
  67 #endif
  68 }