diff options
author | Jim Meyering <jim@meyering.net> | 2006-01-11 13:30:31 +0000 |
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committer | Jim Meyering <jim@meyering.net> | 2006-01-11 13:30:31 +0000 |
commit | c6749127cae6a7debf135dacfff51a9a09e56d74 (patch) | |
tree | 4011dfbbd8a3c00ae33cc49bfd5a194a8bc3009a /lib | |
parent | 06df842f61d75e4f23c2af811fb0d80e56eb272a (diff) | |
download | coreutils-c6749127cae6a7debf135dacfff51a9a09e56d74.tar.xz |
(fchmodat): New file and function.
Diffstat (limited to 'lib')
-rw-r--r-- | lib/fchmodat.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/fchmodat.c b/lib/fchmodat.c new file mode 100644 index 000000000..f8e84534a --- /dev/null +++ b/lib/fchmodat.c @@ -0,0 +1,104 @@ +/* Change the protections of file relative to an open directory. + Copyright (C) 2006 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 <errno.h> + +#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ +#include "save-cwd.h" + +#include "gettext.h" +#define _(msgid) gettext (msgid) + +#include "openat-priv.h" + +/* Some systems don't have ENOSYS. */ +#ifndef ENOSYS +# ifdef ENOTSUP +# define ENOSYS ENOTSUP +# else +/* Some systems don't have ENOTSUP either. */ +# define ENOSYS EINVAL +# endif +#endif + +#ifndef HAVE_LCHMOD +# undef lchmod +# define lchmod(f,m) (errno = ENOSYS, -1) +#endif + +/* Solaris 10 has no function like this. + Invoke chmod or lchmod on file, FILE, using 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. + Note that an attempt to use a FLAG value of AT_SYMLINK_NOFOLLOW + on a system without lchmod support causes this function to fail. */ +int +fchmodat (int fd, char const *file, mode_t mode, int flag) +{ + struct saved_cwd saved_cwd; + int saved_errno; + int err; + + if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) + return (flag == AT_SYMLINK_NOFOLLOW + ? lchmod (file, mode) + : chmod (file, mode)); + + { + char *proc_file; + BUILD_PROC_NAME (proc_file, fd, file); + err = (flag == AT_SYMLINK_NOFOLLOW + ? lchmod (proc_file, mode) + : chmod (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); + + err = fchdir (fd); + saved_errno = errno; + + if (! err) + { + err = (flag == AT_SYMLINK_NOFOLLOW + ? lchmod (file, mode) + : chmod (file, mode)); + saved_errno = errno; + + if (restore_cwd (&saved_cwd) != 0) + openat_restore_fail (errno); + } + + free_cwd (&saved_cwd); + errno = saved_errno; + return err; +} |