guile/lib/spawn_faction_addopen.c

/* Copyright (C) 2000, 2009-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <spawn.h>

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#if !_LIBC
# define __sysconf(open_max) getdtablesize ()
#endif

#if REPLACE_POSIX_SPAWN
# include "spawn_int.h"
#endif

/* Add an action to FILE-ACTIONS which tells the implementation to call
   'open' for the given file during the 'spawn' call.  */
int
posix_spawn_file_actions_addopen (posix_spawn_file_actions_t *file_actions,
                                  int fd, const char *path, int oflag,
                                  mode_t mode)
#undef posix_spawn_file_actions_addopen
{
  int maxfd = __sysconf (_SC_OPEN_MAX);

  /* Test for the validity of the file descriptor.  */
  if (fd < 0 || fd >= maxfd)
    return EBADF;

#if !REPLACE_POSIX_SPAWN
  return posix_spawn_file_actions_addopen (file_actions, fd, path, oflag, mode);
#else
  {
    /* Copy PATH, because the caller may free it before calling posix_spawn()
       or posix_spawnp().  */
    char *path_copy = strdup (path);
    if (path_copy == NULL)
      return ENOMEM;

    /* Allocate more memory if needed.  */
    if (file_actions->_used == file_actions->_allocated
        && __posix_spawn_file_actions_realloc (file_actions) != 0)
      {
        /* This can only mean we ran out of memory.  */
        free (path_copy);
        return ENOMEM;
      }

    {
      struct __spawn_action *rec;

      /* Add the new value.  */
      rec = &file_actions->_actions[file_actions->_used];
      rec->tag = spawn_do_open;
      rec->action.open_action.fd = fd;
      rec->action.open_action.path = path_copy;
      rec->action.open_action.oflag = oflag;
      rec->action.open_action.mode = mode;

      /* Account for the new entry.  */
      ++file_actions->_used;

      return 0;
    }
  }
#endif
}