diff options
Diffstat (limited to 'lib/openat.c')
| -rw-r--r-- | lib/openat.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/lib/openat.c b/lib/openat.c new file mode 100644 index 0000000..443cb3d --- /dev/null +++ b/lib/openat.c @@ -0,0 +1,181 @@ +/* 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 <stdarg.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> + +#include "error.h" +#include "exitfail.h" +#include "save-cwd.h" + +#include "gettext.h" +#define _(msgid) gettext (msgid) + +/* Replacement for Solaris' openat function. + <http://www.google.com/search?q=openat+site:docs.sun.com> + Simulate it by doing save_cwd/fchdir/open/restore_cwd. + If either the save_cwd or the restore_cwd fails (relatively unlikely, + and usually indicative of a problem that deserves close attention), + then give a diagnostic and exit nonzero. + Otherwise, upon failure, set errno and return -1, as openat does. + Upon successful completion, return a file descriptor. */ +int +rpl_openat (int fd, char const *file, int flags, ...) +{ + struct saved_cwd saved_cwd; + int saved_errno; + int new_fd; + mode_t mode = 0; + + if (flags & O_CREAT) + { + va_list arg; + va_start (arg, flags); + + /* Assume that mode_t is passed compatibly with mode_t's type + after argument promotion. */ + mode = va_arg (arg, mode_t); + + va_end (arg); + } + + if (fd == AT_FDCWD || *file == '/') + return open (file, flags, mode); + + if (save_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("openat: unable to record current working directory")); + + if (fchdir (fd) != 0) + { + saved_errno = errno; + free_cwd (&saved_cwd); + errno = saved_errno; + return -1; + } + + new_fd = open (file, flags, mode); + saved_errno = errno; + + if (restore_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("openat: unable to restore working directory")); + + free_cwd (&saved_cwd); + + errno = saved_errno; + return new_fd; +} + +/* Replacement for Solaris' function by the same name. + <http://www.google.com/search?q=fdopendir+site:docs.sun.com> + Simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd. + If either the save_cwd or the restore_cwd fails (relatively unlikely, + and usually indicative of a problem that deserves close attention), + then give a diagnostic and exit nonzero. + Otherwise, this function works just like Solaris' fdopendir. */ +DIR * +fdopendir (int fd) +{ + struct saved_cwd saved_cwd; + int saved_errno; + DIR *dir; + + if (fd == AT_FDCWD) + return opendir ("."); + + if (save_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("fdopendir: unable to record current working directory")); + + if (fchdir (fd) != 0) + { + saved_errno = errno; + free_cwd (&saved_cwd); + errno = saved_errno; + return NULL; + } + + dir = opendir ("."); + saved_errno = errno; + + if (restore_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("fdopendir: unable to restore working directory")); + + free_cwd (&saved_cwd); + + errno = saved_errno; + return dir; +} + +/* Replacement for Solaris' function by the same name. + <http://www.google.com/search?q=fstatat+site:docs.sun.com> + Simulate it by doing save_cwd/fchdir/(stat|lstat)/restore_cwd. + If either the save_cwd or the restore_cwd fails (relatively unlikely, + and usually indicative of a problem that deserves close attention), + then give a diagnostic and exit nonzero. + Otherwise, this function works just like Solaris' fstatat. */ +int +fstatat (int fd, char const *file, struct stat *st, int flag) +{ + struct saved_cwd saved_cwd; + int saved_errno; + int err; + + if (fd == AT_FDCWD) + return (flag == AT_SYMLINK_NOFOLLOW + ? lstat (file, st) + : stat (file, st)); + + if (save_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("fstatat: unable to record current working directory")); + + if (fchdir (fd) != 0) + { + saved_errno = errno; + free_cwd (&saved_cwd); + errno = saved_errno; + return -1; + } + + err = (flag == AT_SYMLINK_NOFOLLOW + ? lstat (file, st) + : stat (file, st)); + saved_errno = errno; + + if (restore_cwd (&saved_cwd) != 0) + error (exit_failure, errno, + _("fstatat: unable to restore working directory")); + + free_cwd (&saved_cwd); + + errno = saved_errno; + return err; +} |