rm_/lib/opendirat.c
2020-09-02 16:47:03 +08:00

55 lines
1.7 KiB
C

/* Open a directory relative to another directory.
Copyright 2006-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Written by Jim Meyering and Paul Eggert. */
#include <config.h>
#include <opendirat.h>
#include <errno.h>
#include <fcntl--.h>
#include <unistd.h>
/* Relative to DIR_FD, open the directory DIR, passing EXTRA_FLAGS to
the underlying openat call. On success, store into *PNEW_FD the
underlying file descriptor of the newly opened directory and return
the directory stream. On failure, return NULL and set errno.
On success, *PNEW_FD is at least 3, so this is a "safer" function. */
DIR *
opendirat (int dir_fd, char const *dir, int extra_flags, int *pnew_fd)
{
int open_flags = (O_RDONLY | O_CLOEXEC | O_DIRECTORY | O_NOCTTY
| O_NONBLOCK | extra_flags);
int new_fd = openat (dir_fd, dir, open_flags);
if (new_fd < 0)
return NULL;
DIR *dirp = fdopendir (new_fd);
if (dirp)
*pnew_fd = new_fd;
else
{
int fdopendir_errno = errno;
close (new_fd);
errno = fdopendir_errno;
}
return dirp;
}