/* SPDX-License-Identifier: LGPL-2.1+ */
-/***
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd 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
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
#include <errno.h>
#include <stddef.h>
return 0;
}
+int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
+ /* Under the assumption that we are running privileged we
+ * first change the access mode and only then hand out
+ * ownership to avoid a window where access is too open. */
+
+ if (mode != MODE_INVALID)
+ if (fchmod(fd, mode) < 0)
+ return -errno;
+
+ if (uid != UID_INVALID || gid != GID_INVALID)
+ if (fchown(fd, uid, gid) < 0)
+ return -errno;
+
+ return 0;
+}
+
int fchmod_umask(int fd, mode_t m) {
mode_t u;
int r;
return r;
}
+int fchmod_opath(int fd, mode_t m) {
+ char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
+
+ /* This function operates also on fd that might have been opened with
+ * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like
+ * fchownat() does. */
+
+ xsprintf(procfs_path, "/proc/self/fd/%i", fd);
+
+ if (chmod(procfs_path, m) < 0)
+ return -errno;
+
+ return 0;
+}
+
int fd_warn_permissions(const char *path, int fd) {
struct stat st;
int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) {
_cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
_cleanup_close_ int fd = -1;
- unsigned max_follow = 32; /* how many symlinks to follow before giving up and returning ELOOP */
+ unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */
struct stat previous_stat;
bool exists = true;
char *todo;
assert(path);
/* Either the file may be missing, or we return an fd to the final object, but both make no sense */
- if ((flags & (CHASE_NONEXISTENT|CHASE_OPEN)) == (CHASE_NONEXISTENT|CHASE_OPEN))
+ if (FLAGS_SET(flags, CHASE_NONEXISTENT | CHASE_OPEN))
+ return -EINVAL;
+
+ if (FLAGS_SET(flags, CHASE_STEP | CHASE_OPEN))
return -EINVAL;
if (isempty(path))
* Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got
* as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this
* function what to do when encountering a symlink with an absolute path as directory: prefix it by the
- * specified path. */
+ * specified path.
+ *
+ * There are three ways to invoke this function:
+ *
+ * 1. Without CHASE_STEP or CHASE_OPEN: in this case the path is resolved and the normalized path is returned
+ * in `ret`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set 0 is returned if the file
+ * doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set >= 0 is returned if the destination was
+ * found, -ENOENT if it doesn't.
+ *
+ * 2. With CHASE_OPEN: in this case the destination is opened after chasing it as O_PATH and this file
+ * descriptor is returned as return value. This is useful to open files relative to some root
+ * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using
+ * fd_reopen() or such) before it can be used for reading/writing. CHASE_OPEN may not be combined with
+ * CHASE_NONEXISTENT.
+ *
+ * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first
+ * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if
+ * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the
+ * path is fully normalized, and == 0 for each normalization step. This may be combined with
+ * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found.
+ *
+ * */
/* A root directory of "/" or "" is identical to none */
- if (isempty(original_root) || path_equal(original_root, "/"))
+ if (empty_or_root(original_root))
original_root = NULL;
+ if (!original_root && !ret && (flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_OPEN|CHASE_STEP)) == CHASE_OPEN) {
+ /* Shortcut the CHASE_OPEN case if the caller isn't interested in the actual path and has no root set
+ * and doesn't care about any of the other special features we provide either. */
+ r = open(path, O_PATH|O_CLOEXEC);
+ if (r < 0)
+ return -errno;
+
+ return r;
+ }
+
if (original_root) {
r = path_make_absolute_cwd(original_root, &root);
if (r < 0)
/* Just a single slash? Then we reached the end. */
if (path_equal(first, "/")) {
/* Preserve the trailing slash */
- if (!strextend(&done, "/", NULL))
- return -ENOMEM;
+
+ if (flags & CHASE_TRAIL_SLASH)
+ if (!strextend(&done, "/", NULL))
+ return -ENOMEM;
break;
}
/* If we already are at the top, then going up will not change anything. This is in-line with
* how the kernel handles this. */
- if (isempty(done) || path_equal(done, "/"))
+ if (empty_or_root(done))
continue;
parent = dirname_malloc(done);
free_and_replace(done, parent);
+ if (flags & CHASE_STEP)
+ goto chased_one;
+
fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH);
if (fd_parent < 0)
return -errno;
free(buffer);
todo = buffer = joined;
+ if (flags & CHASE_STEP)
+ goto chased_one;
+
continue;
}
return TAKE_FD(fd);
}
+ if (flags & CHASE_STEP)
+ return 1;
+
return exists;
+
+chased_one:
+ if (ret) {
+ char *c;
+
+ c = strjoin(strempty(done), todo);
+ if (!c)
+ return -ENOMEM;
+
+ *ret = c;
+ }
+
+ return 0;
+}
+
+int chase_symlinks_and_open(
+ const char *path,
+ const char *root,
+ unsigned chase_flags,
+ int open_flags,
+ char **ret_path) {
+
+ _cleanup_close_ int path_fd = -1;
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ if (chase_flags & CHASE_NONEXISTENT)
+ return -EINVAL;
+
+ if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
+ /* Shortcut this call if none of the special features of this call are requested */
+ r = open(path, open_flags);
+ if (r < 0)
+ return -errno;
+
+ return r;
+ }
+
+ path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
+ if (path_fd < 0)
+ return path_fd;
+
+ r = fd_reopen(path_fd, open_flags);
+ if (r < 0)
+ return r;
+
+ if (ret_path)
+ *ret_path = TAKE_PTR(p);
+
+ return r;
+}
+
+int chase_symlinks_and_opendir(
+ const char *path,
+ const char *root,
+ unsigned chase_flags,
+ char **ret_path,
+ DIR **ret_dir) {
+
+ char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
+ _cleanup_close_ int path_fd = -1;
+ _cleanup_free_ char *p = NULL;
+ DIR *d;
+
+ if (!ret_dir)
+ return -EINVAL;
+ if (chase_flags & CHASE_NONEXISTENT)
+ return -EINVAL;
+
+ if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
+ /* Shortcut this call if none of the special features of this call are requested */
+ d = opendir(path);
+ if (!d)
+ return -errno;
+
+ *ret_dir = d;
+ return 0;
+ }
+
+ path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
+ if (path_fd < 0)
+ return path_fd;
+
+ xsprintf(procfs_path, "/proc/self/fd/%i", path_fd);
+ d = opendir(procfs_path);
+ if (!d)
+ return -errno;
+
+ if (ret_path)
+ *ret_path = TAKE_PTR(p);
+
+ *ret_dir = d;
+ return 0;
+}
+
+int chase_symlinks_and_stat(
+ const char *path,
+ const char *root,
+ unsigned chase_flags,
+ char **ret_path,
+ struct stat *ret_stat) {
+
+ _cleanup_close_ int path_fd = -1;
+ _cleanup_free_ char *p = NULL;
+
+ assert(path);
+ assert(ret_stat);
+
+ if (chase_flags & CHASE_NONEXISTENT)
+ return -EINVAL;
+
+ if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
+ /* Shortcut this call if none of the special features of this call are requested */
+ if (stat(path, ret_stat) < 0)
+ return -errno;
+
+ return 1;
+ }
+
+ path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
+ if (path_fd < 0)
+ return path_fd;
+
+ if (fstat(path_fd, ret_stat) < 0)
+ return -errno;
+
+ if (ret_path)
+ *ret_path = TAKE_PTR(p);
+
+ if (chase_flags & CHASE_OPEN)
+ return TAKE_FD(path_fd);
+
+ return 1;
}
int access_fd(int fd, int mode) {
/* Like access() but operates on an already open fd */
xsprintf(p, "/proc/self/fd/%i", fd);
-
r = access(p, mode);
if (r < 0)
- r = -errno;
+ return -errno;
return r;
}
+void unlink_tempfilep(char (*p)[]) {
+ /* If the file is created with mkstemp(), it will (almost always)
+ * change the suffix. Treat this as a sign that the file was
+ * successfully created. We ignore both the rare case where the
+ * original suffix is used and unlink failures. */
+ if (!endswith(*p, ".XXXXXX"))
+ (void) unlink_noerrno(*p);
+}
+
int unlinkat_deallocate(int fd, const char *name, int flags) {
_cleanup_close_ int truncate_fd = -1;
struct stat st;
r = fd_get_path(fd, &path);
if (r < 0) {
- log_debug("Failed to query /proc/self/fd/%d%s: %m",
- fd,
- r == -EOPNOTSUPP ? ", ignoring" : "");
+ log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m",
+ fd,
+ r == -EOPNOTSUPP ? ", ignoring" : "");
if (r == -EOPNOTSUPP)
/* If /proc is not available, we're most likely running in some
~ianmdlvl / elogind.git / blobdiff