X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=lib%2Fopenat.c;fp=lib%2Fopenat.c;h=0000000000000000000000000000000000000000;hb=22f1eb8bc17e5be72dd23d42d6aaa60196ac22e6;hp=0c32672215ceadb74bb7e3379efb645bfc58cb6f;hpb=00fa13ff3f2d5b6e2a94c5e948c38616ff7ad37a;p=tar diff --git a/lib/openat.c b/lib/openat.c deleted file mode 100644 index 0c32672..0000000 --- a/lib/openat.c +++ /dev/null @@ -1,268 +0,0 @@ -/* provide a replacement openat function - Copyright (C) 2004, 2005, 2006, 2007, 2008 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 . */ - -/* written by Jim Meyering */ - -#include - -#include "openat.h" - -#include -#include -#include - -#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ -#include "fcntl--.h" -#include "openat-priv.h" -#include "save-cwd.h" - -/* Replacement for Solaris' openat function. - - First, try to simulate it via open ("/proc/self/fd/FD/FILE"). - Failing that, simulate it by doing save_cwd/fchdir/open/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - 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 -openat (int fd, char const *file, int flags, ...) -{ - mode_t mode = 0; - - if (flags & O_CREAT) - { - va_list arg; - va_start (arg, flags); - - /* If mode_t is narrower than int, use the promoted type (int), - not mode_t. Use sizeof to guess whether mode_t is narrower; - we don't know of any practical counterexamples. */ - mode = (sizeof (mode_t) < sizeof (int) - ? va_arg (arg, int) - : va_arg (arg, mode_t)); - - va_end (arg); - } - - return openat_permissive (fd, file, flags, mode, NULL); -} - -/* Like openat (FD, FILE, FLAGS, MODE), but if CWD_ERRNO is - nonnull, set *CWD_ERRNO to an errno value if unable to save - or restore the initial working directory. This is needed only - the first time remove.c's remove_dir opens a command-line - directory argument. - - If a previous attempt to restore the current working directory - failed, then we must not even try to access a `.'-relative name. - It is the caller's responsibility not to call this function - in that case. */ - -int -openat_permissive (int fd, char const *file, int flags, mode_t mode, - int *cwd_errno) -{ - struct saved_cwd saved_cwd; - int saved_errno; - int err; - bool save_ok; - - if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) - return open (file, flags, mode); - - { - char buf[OPENAT_BUFFER_SIZE]; - char *proc_file = openat_proc_name (buf, fd, file); - if (proc_file) - { - int open_result = open (proc_file, flags, mode); - int open_errno = errno; - if (proc_file != buf) - free (proc_file); - /* 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 <= open_result || ! EXPECTED_ERRNO (open_errno)) - { - errno = open_errno; - return open_result; - } - } - } - - save_ok = (save_cwd (&saved_cwd) == 0); - if (! save_ok) - { - if (! cwd_errno) - openat_save_fail (errno); - *cwd_errno = errno; - } - - err = fchdir (fd); - saved_errno = errno; - - if (! err) - { - err = open (file, flags, mode); - saved_errno = errno; - if (save_ok && restore_cwd (&saved_cwd) != 0) - { - if (! cwd_errno) - openat_restore_fail (errno); - *cwd_errno = errno; - } - } - - free_cwd (&saved_cwd); - errno = saved_errno; - return err; -} - -/* Return true if our openat implementation must resort to - using save_cwd and restore_cwd. */ -bool -openat_needs_fchdir (void) -{ - bool needs_fchdir = true; - int fd = open ("/", O_RDONLY); - - if (0 <= fd) - { - char buf[OPENAT_BUFFER_SIZE]; - char *proc_file = openat_proc_name (buf, fd, "."); - if (proc_file) - { - needs_fchdir = false; - if (proc_file != buf) - free (proc_file); - } - close (fd); - } - - return needs_fchdir; -} - -#if !HAVE_FDOPENDIR - -/* Replacement for Solaris' function by the same name. - - First, try to simulate it via opendir ("/proc/self/fd/FD"). Failing - that, simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' fdopendir. - - W A R N I N G: - Unlike the other fd-related functions here, this one - effectively consumes its FD parameter. The caller should not - close or otherwise manipulate FD if this function returns successfully. */ -DIR * -fdopendir (int fd) -{ - struct saved_cwd saved_cwd; - int saved_errno; - DIR *dir; - - char buf[OPENAT_BUFFER_SIZE]; - char *proc_file = openat_proc_name (buf, fd, "."); - if (proc_file) - { - dir = opendir (proc_file); - saved_errno = errno; - } - else - { - dir = NULL; - saved_errno = EOPNOTSUPP; - } - - /* If the syscall fails with an expected errno value, resort to - save_cwd/restore_cwd. */ - if (! dir && EXPECTED_ERRNO (saved_errno)) - { - if (save_cwd (&saved_cwd) != 0) - openat_save_fail (errno); - - if (fchdir (fd) != 0) - { - dir = NULL; - saved_errno = errno; - } - else - { - dir = opendir ("."); - saved_errno = errno; - - if (restore_cwd (&saved_cwd) != 0) - openat_restore_fail (errno); - } - - free_cwd (&saved_cwd); - } - - if (dir) - close (fd); - if (proc_file != buf) - free (proc_file); - errno = saved_errno; - return dir; -} - -#endif - -/* Replacement for Solaris' function by the same name. - - First, try to simulate it via l?stat ("/proc/self/fd/FD/FILE"). - Failing that, simulate it via save_cwd/fchdir/(stat|lstat)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' fstatat. */ - -#define AT_FUNC_NAME fstatat -#define AT_FUNC_F1 lstat -#define AT_FUNC_F2 stat -#define AT_FUNC_USE_F1_COND flag == AT_SYMLINK_NOFOLLOW -#define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat *st, int flag -#define AT_FUNC_POST_FILE_ARGS , st -#include "at-func.c" -#undef AT_FUNC_NAME -#undef AT_FUNC_F1 -#undef AT_FUNC_F2 -#undef AT_FUNC_USE_F1_COND -#undef AT_FUNC_POST_FILE_PARAM_DECLS -#undef AT_FUNC_POST_FILE_ARGS - -/* Replacement for Solaris' function by the same name. - - First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE"). - Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' unlinkat. */ - -#define AT_FUNC_NAME unlinkat -#define AT_FUNC_F1 rmdir -#define AT_FUNC_F2 unlink -#define AT_FUNC_USE_F1_COND flag == AT_REMOVEDIR -#define AT_FUNC_POST_FILE_PARAM_DECLS , int flag -#define AT_FUNC_POST_FILE_ARGS /* empty */ -#include "at-func.c" -#undef AT_FUNC_NAME -#undef AT_FUNC_F1 -#undef AT_FUNC_F2 -#undef AT_FUNC_USE_F1_COND -#undef AT_FUNC_POST_FILE_PARAM_DECLS -#undef AT_FUNC_POST_FILE_ARGS