diff options
author | Jim Meyering <jim@meyering.net> | 2005-11-30 12:39:14 +0000 |
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committer | Jim Meyering <jim@meyering.net> | 2005-11-30 12:39:14 +0000 |
commit | 2e72b76fd352ea3dc85374da8b41e2307c7e14da (patch) | |
tree | b5bb6b14ba51ce121c636627ceb8b2f42704c0f9 /lib/mkdirat.c | |
parent | 76b8c64505df1ce3f37c294b70560839a0494a39 (diff) | |
download | coreutils-2e72b76fd352ea3dc85374da8b41e2307c7e14da.tar.xz |
(mkdirat): New file and function.
Diffstat (limited to 'lib/mkdirat.c')
-rw-r--r-- | lib/mkdirat.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/lib/mkdirat.c b/lib/mkdirat.c new file mode 100644 index 000000000..140f96a96 --- /dev/null +++ b/lib/mkdirat.c @@ -0,0 +1,118 @@ +/* provide a replacement openat function + Copyright (C) 2004, 2005 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 2, 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, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* written by Jim Meyering */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include "openat.h" + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> + +#include "alloca.h" +#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ +#include "intprops.h" +#include "save-cwd.h" + +#include "gettext.h" +#define _(msgid) gettext (msgid) + +/* Set PROC_FD_FILENAME to the expansion of "/proc/self/fd/%d/%s" in + alloca'd memory, using FD and FILE, respectively for %d and %s. */ +#define BUILD_PROC_NAME(Proc_fd_filename, Fd, File) \ + do \ + { \ + size_t filelen = strlen (File); \ + static const char procfd[] = "/proc/self/fd/%d/%s"; \ + /* Buffer for the file name we are going to use. It consists of \ + - the string /proc/self/fd/ \ + - the file descriptor number \ + - the file name provided. \ + The final NUL is included in the sizeof. \ + Subtract 4 to account for %d and %s. */ \ + size_t buflen = sizeof (procfd) - 4 + INT_STRLEN_BOUND (Fd) + filelen; \ + (Proc_fd_filename) = alloca (buflen); \ + snprintf ((Proc_fd_filename), buflen, procfd, (Fd), (File)); \ + } \ + while (0) + +/* Trying to access a BUILD_PROC_NAME file will fail on systems without + /proc support, and even on systems *with* ProcFS support. Return + nonzero if the failure may be legitimate, e.g., because /proc is not + readable, or the particular .../fd/N directory is not present. */ +#define EXPECTED_ERRNO(Errno) \ + ((Errno) == ENOTDIR || (Errno) == ENOENT \ + || (Errno) == EPERM || (Errno) == EACCES \ + || (Errno) == EOPNOTSUPP /* FreeBSD */) + +/* Solaris 10 has no function like this. + Create a subdirectory, FILE, with mode MODE, in the directory + open on descriptor FD. If possible, do it without changing the + working directory. Otherwise, resort to using save_cwd/fchdir, + then mkdir/restore_cwd. If either the save_cwd or the restore_cwd + fails, then give a diagnostic and exit nonzero. */ +int +mkdirat (int fd, char const *file, mode_t mode) +{ + struct saved_cwd saved_cwd; + int saved_errno; + int err; + + if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) + return mkdir (file, mode); + + { + char *proc_file; + BUILD_PROC_NAME (proc_file, fd, file); + err = mkdir (proc_file, mode); + /* If the syscall succeeds, or if it fails with an unexpected + errno value, then return right away. Otherwise, fall through + and resort to using save_cwd/restore_cwd. */ + if (0 <= err || ! EXPECTED_ERRNO (errno)) + return err; + } + + if (save_cwd (&saved_cwd) != 0) + openat_save_fail (errno); + + if (fchdir (fd) != 0) + { + saved_errno = errno; + free_cwd (&saved_cwd); + errno = saved_errno; + return -1; + } + + err = mkdir (file, mode); + saved_errno = (err < 0 ? errno : 0); + + if (restore_cwd (&saved_cwd) != 0) + openat_restore_fail (errno); + + free_cwd (&saved_cwd); + + if (saved_errno) + errno = saved_errno; + return err; +} |