| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <linux/magic.h> |
| |
| #include "alloc-util.h" |
| #include "chase-symlinks.h" |
| #include "fd-util.h" |
| #include "fileio.h" |
| #include "fs-util.h" |
| #include "glyph-util.h" |
| #include "log.h" |
| #include "path-util.h" |
| #include "string-util.h" |
| #include "user-util.h" |
| |
| bool unsafe_transition(const struct stat *a, const struct stat *b) { |
| /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to |
| * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files |
| * making us believe we read something safe even though it isn't safe in the specific context we open it in. */ |
| |
| if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */ |
| return false; |
| |
| return a->st_uid != b->st_uid; /* Otherwise we need to stay within the same UID */ |
| } |
| |
| static int log_unsafe_transition(int a, int b, const char *path, ChaseSymlinksFlags flags) { |
| _cleanup_free_ char *n1 = NULL, *n2 = NULL, *user_a = NULL, *user_b = NULL; |
| struct stat st; |
| |
| if (!FLAGS_SET(flags, CHASE_WARN)) |
| return -ENOLINK; |
| |
| (void) fd_get_path(a, &n1); |
| (void) fd_get_path(b, &n2); |
| |
| if (fstat(a, &st) == 0) |
| user_a = uid_to_name(st.st_uid); |
| if (fstat(b, &st) == 0) |
| user_b = uid_to_name(st.st_uid); |
| |
| return log_warning_errno(SYNTHETIC_ERRNO(ENOLINK), |
| "Detected unsafe path transition %s (owned by %s) %s %s (owned by %s) during canonicalization of %s.", |
| strna(n1), strna(user_a), special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), strna(n2), strna(user_b), path); |
| } |
| |
| static int log_autofs_mount_point(int fd, const char *path, ChaseSymlinksFlags flags) { |
| _cleanup_free_ char *n1 = NULL; |
| |
| if (!FLAGS_SET(flags, CHASE_WARN)) |
| return -EREMOTE; |
| |
| (void) fd_get_path(fd, &n1); |
| |
| return log_warning_errno(SYNTHETIC_ERRNO(EREMOTE), |
| "Detected autofs mount point %s during canonicalization of %s.", |
| strna(n1), path); |
| } |
| |
| static int log_prohibited_symlink(int fd, ChaseSymlinksFlags flags) { |
| _cleanup_free_ char *n1 = NULL; |
| |
| assert(fd >= 0); |
| |
| if (!FLAGS_SET(flags, CHASE_WARN)) |
| return -EREMCHG; |
| |
| (void) fd_get_path(fd, &n1); |
| |
| return log_warning_errno(SYNTHETIC_ERRNO(EREMCHG), |
| "Detected symlink where not symlink is allowed at %s, refusing.", |
| strna(n1)); |
| } |
| |
| int chase_symlinks_at( |
| int dir_fd, |
| const char *path, |
| ChaseSymlinksFlags flags, |
| char **ret_path, |
| int *ret_fd) { |
| |
| _cleanup_free_ char *buffer = NULL, *done = NULL; |
| _cleanup_close_ int fd = -EBADF, root_fd = -EBADF; |
| unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */ |
| bool exists = true, append_trail_slash = false; |
| struct stat previous_stat; |
| const char *todo; |
| int r; |
| |
| assert(path); |
| assert(!FLAGS_SET(flags, CHASE_PREFIX_ROOT)); |
| assert(dir_fd >= 0 || dir_fd == AT_FDCWD); |
| |
| /* Either the file may be missing, or we return an fd to the final object, but both make no sense */ |
| if ((flags & CHASE_NONEXISTENT) && ret_fd) |
| return -EINVAL; |
| |
| if ((flags & CHASE_STEP) && ret_fd) |
| return -EINVAL; |
| |
| if (isempty(path)) |
| path = "."; |
| |
| /* This function resolves symlinks of the path relative to the given directory file descriptor. If |
| * CHASE_SYMLINKS_RESOLVE_IN_ROOT is specified and a directory file descriptor is provided, symlinks |
| * are resolved relative to the given directory file descriptor. Otherwise, they are resolved |
| * relative to the root directory of the host. |
| * |
| * Note that when a positive directory file descriptor is provided and CHASE_AT_RESOLVE_IN_ROOT is |
| * specified and we find an absolute symlink, it is resolved relative to given directory file |
| * descriptor and not the root of the host. Also, when following relative symlinks, this functions |
| * ensures they cannot be used to "escape" the given directory file descriptor. If a positive |
| * directory file descriptor is provided, the "path" parameter is always interpreted relative to the |
| * given directory file descriptor, even if it is absolute. If the given directory file descriptor is |
| * AT_FDCWD and "path" is absolute, it is interpreted relative to the root directory of the host. |
| * |
| * If "dir_fd" is a valid directory fd, "path" is an absolute path and "ret_path" is not NULL, this |
| * functions returns a relative path in "ret_path" because openat() like functions generally ignore |
| * the directory fd if they are provided with an absolute path. On the other hand, if "dir_fd" is |
| * AT_FDCWD and "path" is an absolute path, we return an absolute path in "ret_path" because |
| * otherwise, if the caller passes the returned relative path to another openat() like function, it |
| * would be resolved relative to the current working directory instead of to "/". |
| * |
| * Algorithmically this operates on two path buffers: "done" are the components of the path we |
| * already processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we |
| * still need to process. On each iteration, we move one component from "todo" to "done", processing |
| * its special meaning each time. We always keep an O_PATH fd to the component we are currently |
| * processing, thus keeping lookup races to a minimum. |
| * |
| * 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 |
| * "dir_fd" parameter to tell this function what to do when encountering a symlink with an absolute |
| * path as directory: resolve it relative to the given directory file descriptor. |
| * |
| * There are five ways to invoke this function: |
| * |
| * 1. Without CHASE_STEP or ret_fd: in this case the path is resolved and the normalized path is |
| * returned in `ret_path`. 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 wasn't. |
| * |
| * 2. With ret_fd: 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. ret_fd 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 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. |
| * |
| * 4. With CHASE_SAFE: in this case the path must not contain unsafe transitions, i.e. transitions |
| * from unprivileged to privileged files or directories. In such cases the return value is |
| * -ENOLINK. If CHASE_WARN is also set, a warning describing the unsafe transition is emitted. |
| * CHASE_WARN cannot be used in PID 1. |
| * |
| * 5. With CHASE_NO_AUTOFS: in this case if an autofs mount point is encountered, path normalization |
| * is aborted and -EREMOTE is returned. If CHASE_WARN is also set, a warning showing the path of |
| * the mount point is emitted. CHASE_WARN cannot be used in PID 1. |
| */ |
| |
| if (!(flags & (CHASE_AT_RESOLVE_IN_ROOT|CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_STEP)) && |
| !ret_path && ret_fd) { |
| |
| /* Shortcut the ret_fd 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 = openat(dir_fd, path, O_PATH|O_CLOEXEC|((flags & CHASE_NOFOLLOW) ? O_NOFOLLOW : 0)); |
| if (r < 0) |
| return -errno; |
| |
| *ret_fd = r; |
| return 0; |
| } |
| |
| buffer = strdup(path); |
| if (!buffer) |
| return -ENOMEM; |
| |
| /* If we receive an absolute path together with AT_FDCWD, we need to return an absolute path, because |
| * a relative path would be interpreted relative to the current working directory. */ |
| bool need_absolute = dir_fd == AT_FDCWD && path_is_absolute(path); |
| if (need_absolute) { |
| done = strdup("/"); |
| if (!done) |
| return -ENOMEM; |
| } |
| |
| /* If we get AT_FDCWD, we always resolve symlinks relative to the host's root. Only if a positive |
| * directory file descriptor is provided will we look at CHASE_AT_RESOLVE_IN_ROOT to determine |
| * whether to resolve symlinks in it or not. */ |
| if (dir_fd >= 0 && FLAGS_SET(flags, CHASE_AT_RESOLVE_IN_ROOT)) |
| root_fd = openat(dir_fd, ".", O_CLOEXEC|O_DIRECTORY|O_PATH); |
| else |
| root_fd = open("/", O_CLOEXEC|O_DIRECTORY|O_PATH); |
| if (root_fd < 0) |
| return -errno; |
| |
| /* If a positive directory file descriptor is provided, always resolve the given path relative to it, |
| * regardless of whether it is absolute or not. If we get AT_FDCWD, follow regular openat() |
| * semantics, if the path is relative, resolve against the current working directory. Otherwise, |
| * resolve against root. */ |
| if (dir_fd >= 0 || !path_is_absolute(path)) |
| fd = openat(dir_fd, ".", O_CLOEXEC|O_DIRECTORY|O_PATH); |
| else |
| fd = open("/", O_CLOEXEC|O_DIRECTORY|O_PATH); |
| if (fd < 0) |
| return -errno; |
| |
| if (fstat(fd, &previous_stat) < 0) |
| return -errno; |
| |
| if (flags & CHASE_TRAIL_SLASH) |
| append_trail_slash = endswith(buffer, "/") || endswith(buffer, "/."); |
| |
| for (todo = buffer;;) { |
| _cleanup_free_ char *first = NULL; |
| _cleanup_close_ int child = -EBADF; |
| struct stat st; |
| const char *e; |
| |
| r = path_find_first_component(&todo, /* accept_dot_dot= */ true, &e); |
| if (r < 0) |
| return r; |
| if (r == 0) { /* We reached the end. */ |
| if (append_trail_slash) |
| if (!strextend(&done, "/")) |
| return -ENOMEM; |
| break; |
| } |
| |
| first = strndup(e, r); |
| if (!first) |
| return -ENOMEM; |
| |
| /* Two dots? Then chop off the last bit of what we already found out. */ |
| if (path_equal(first, "..")) { |
| _cleanup_free_ char *parent = NULL; |
| _cleanup_close_ int fd_parent = -EBADF; |
| |
| /* 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 (empty_or_root(done) && FLAGS_SET(flags, CHASE_AT_RESOLVE_IN_ROOT)) |
| continue; |
| |
| fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH|O_DIRECTORY); |
| if (fd_parent < 0) |
| return -errno; |
| |
| if (fstat(fd_parent, &st) < 0) |
| return -errno; |
| |
| /* If we opened the same directory, that means we're at the host root directory, so |
| * going up won't change anything. */ |
| if (st.st_dev == previous_stat.st_dev && st.st_ino == previous_stat.st_ino) |
| continue; |
| |
| r = path_extract_directory(done, &parent); |
| if (r >= 0 || r == -EDESTADDRREQ) |
| free_and_replace(done, parent); |
| else if (IN_SET(r, -EINVAL, -EADDRNOTAVAIL)) { |
| /* If we're at the top of "dir_fd", start appending ".." to "done". */ |
| if (!path_extend(&done, "..")) |
| return -ENOMEM; |
| } else |
| return r; |
| |
| if (flags & CHASE_STEP) |
| goto chased_one; |
| |
| if (flags & CHASE_SAFE) { |
| if (unsafe_transition(&previous_stat, &st)) |
| return log_unsafe_transition(fd, fd_parent, path, flags); |
| |
| previous_stat = st; |
| } |
| |
| close_and_replace(fd, fd_parent); |
| |
| continue; |
| } |
| |
| /* Otherwise let's see what this is. */ |
| child = openat(fd, first, O_CLOEXEC|O_NOFOLLOW|O_PATH); |
| if (child < 0) { |
| if (errno == ENOENT && |
| (flags & CHASE_NONEXISTENT) && |
| (isempty(todo) || path_is_safe(todo))) { |
| /* If CHASE_NONEXISTENT is set, and the path does not exist, then |
| * that's OK, return what we got so far. But don't allow this if the |
| * remaining path contains "../" or something else weird. */ |
| |
| if (!path_extend(&done, first, todo)) |
| return -ENOMEM; |
| |
| exists = false; |
| break; |
| } |
| |
| return -errno; |
| } |
| |
| if (fstat(child, &st) < 0) |
| return -errno; |
| if ((flags & CHASE_SAFE) && |
| unsafe_transition(&previous_stat, &st)) |
| return log_unsafe_transition(fd, child, path, flags); |
| |
| previous_stat = st; |
| |
| if ((flags & CHASE_NO_AUTOFS) && |
| fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0) |
| return log_autofs_mount_point(child, path, flags); |
| |
| if (S_ISLNK(st.st_mode) && !((flags & CHASE_NOFOLLOW) && isempty(todo))) { |
| _cleanup_free_ char *destination = NULL; |
| |
| if (flags & CHASE_PROHIBIT_SYMLINKS) |
| return log_prohibited_symlink(child, flags); |
| |
| /* This is a symlink, in this case read the destination. But let's make sure we |
| * don't follow symlinks without bounds. */ |
| if (--max_follow <= 0) |
| return -ELOOP; |
| |
| r = readlinkat_malloc(fd, first, &destination); |
| if (r < 0) |
| return r; |
| if (isempty(destination)) |
| return -EINVAL; |
| |
| if (path_is_absolute(destination)) { |
| |
| /* An absolute destination. Start the loop from the beginning, but use the |
| * root file descriptor as base. */ |
| |
| safe_close(fd); |
| fd = fd_reopen(root_fd, O_CLOEXEC|O_PATH|O_DIRECTORY); |
| if (fd < 0) |
| return fd; |
| |
| if (flags & CHASE_SAFE) { |
| if (fstat(fd, &st) < 0) |
| return -errno; |
| |
| if (unsafe_transition(&previous_stat, &st)) |
| return log_unsafe_transition(child, fd, path, flags); |
| |
| previous_stat = st; |
| } |
| |
| r = free_and_strdup(&done, need_absolute ? "/" : NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| /* Prefix what's left to do with what we just read, and start the loop again, but |
| * remain in the current directory. */ |
| if (!path_extend(&destination, todo)) |
| return -ENOMEM; |
| |
| free_and_replace(buffer, destination); |
| todo = buffer; |
| |
| if (flags & CHASE_STEP) |
| goto chased_one; |
| |
| continue; |
| } |
| |
| /* If this is not a symlink, then let's just add the name we read to what we already verified. */ |
| if (!path_extend(&done, first)) |
| return -ENOMEM; |
| |
| /* And iterate again, but go one directory further down. */ |
| close_and_replace(fd, child); |
| } |
| |
| if (ret_path) |
| *ret_path = TAKE_PTR(done); |
| |
| if (ret_fd) { |
| /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a |
| * proper fd by opening /proc/self/fd/xyz. */ |
| |
| assert(fd >= 0); |
| *ret_fd = TAKE_FD(fd); |
| } |
| |
| if (flags & CHASE_STEP) |
| return 1; |
| |
| return exists; |
| |
| chased_one: |
| if (ret_path) { |
| const char *e; |
| |
| /* todo may contain slashes at the beginning. */ |
| r = path_find_first_component(&todo, /* accept_dot_dot= */ true, &e); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| *ret_path = TAKE_PTR(done); |
| else { |
| char *c; |
| |
| c = path_join(done, e); |
| if (!c) |
| return -ENOMEM; |
| |
| *ret_path = c; |
| } |
| } |
| |
| return 0; |
| } |
| |
| int chase_symlinks( |
| const char *path, |
| const char *original_root, |
| ChaseSymlinksFlags flags, |
| char **ret_path, |
| int *ret_fd) { |
| |
| _cleanup_free_ char *root = NULL, *absolute = NULL, *p = NULL; |
| _cleanup_close_ int fd = -EBADF, pfd = -EBADF; |
| int r; |
| |
| assert(path); |
| |
| if (isempty(path)) |
| return -EINVAL; |
| |
| /* A root directory of "/" or "" is identical to none */ |
| if (empty_or_root(original_root)) |
| original_root = NULL; |
| |
| if (original_root) { |
| r = path_make_absolute_cwd(original_root, &root); |
| if (r < 0) |
| return r; |
| |
| /* Simplify the root directory, so that it has no duplicate slashes and nothing at the |
| * end. While we won't resolve the root path we still simplify it. Note that dropping the |
| * trailing slash should not change behaviour, since when opening it we specify O_DIRECTORY |
| * anyway. Moreover at the end of this function after processing everything we'll always turn |
| * the empty string back to "/". */ |
| delete_trailing_chars(root, "/"); |
| path_simplify(root); |
| |
| if (flags & CHASE_PREFIX_ROOT) { |
| absolute = path_join(root, path); |
| if (!absolute) |
| return -ENOMEM; |
| } |
| } |
| |
| if (!absolute) { |
| r = path_make_absolute_cwd(path, &absolute); |
| if (r < 0) |
| return r; |
| } |
| |
| path = path_startswith(absolute, empty_to_root(root)); |
| if (!path) |
| return log_full_errno(flags & CHASE_WARN ? LOG_WARNING : LOG_DEBUG, |
| SYNTHETIC_ERRNO(ECHRNG), |
| "Specified path '%s' is outside of specified root directory '%s', refusing to resolve.", |
| absolute, empty_to_root(root)); |
| |
| fd = open(empty_to_root(root), O_CLOEXEC|O_DIRECTORY|O_PATH); |
| if (fd < 0) |
| return -errno; |
| |
| flags |= CHASE_AT_RESOLVE_IN_ROOT; |
| flags &= ~CHASE_PREFIX_ROOT; |
| |
| r = chase_symlinks_at(fd, path, flags, ret_path ? &p : NULL, ret_fd ? &pfd : NULL); |
| if (r < 0) |
| return r; |
| |
| if (ret_path) { |
| char *q = path_join(empty_to_root(root), p); |
| if (!q) |
| return -ENOMEM; |
| |
| *ret_path = TAKE_PTR(q); |
| } |
| |
| if (ret_fd) |
| *ret_fd = TAKE_FD(pfd); |
| |
| return r; |
| } |
| |
| int chase_symlinks_and_open( |
| const char *path, |
| const char *root, |
| ChaseSymlinksFlags chase_flags, |
| int open_flags, |
| char **ret_path) { |
| |
| _cleanup_close_ int path_fd = -EBADF; |
| _cleanup_free_ char *p = NULL; |
| int r; |
| |
| if (chase_flags & (CHASE_NONEXISTENT|CHASE_STEP)) |
| 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 | (FLAGS_SET(chase_flags, CHASE_NOFOLLOW) ? O_NOFOLLOW : 0)); |
| if (r < 0) |
| return -errno; |
| |
| return r; |
| } |
| |
| r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
| if (r < 0) |
| return r; |
| assert(path_fd >= 0); |
| |
| 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, |
| ChaseSymlinksFlags chase_flags, |
| char **ret_path, |
| DIR **ret_dir) { |
| |
| _cleanup_close_ int path_fd = -EBADF; |
| _cleanup_free_ char *p = NULL; |
| DIR *d; |
| int r; |
| |
| if (!ret_dir) |
| return -EINVAL; |
| if (chase_flags & (CHASE_NONEXISTENT|CHASE_STEP)) |
| 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; |
| } |
| |
| r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
| if (r < 0) |
| return r; |
| assert(path_fd >= 0); |
| |
| d = xopendirat(path_fd, ".", O_NOFOLLOW); |
| 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, |
| ChaseSymlinksFlags chase_flags, |
| char **ret_path, |
| struct stat *ret_stat, |
| int *ret_fd) { |
| |
| _cleanup_close_ int path_fd = -EBADF; |
| _cleanup_free_ char *p = NULL; |
| int r; |
| |
| assert(path); |
| assert(ret_stat); |
| |
| if (chase_flags & (CHASE_NONEXISTENT|CHASE_STEP)) |
| return -EINVAL; |
| |
| if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0 && !ret_fd) { |
| /* Shortcut this call if none of the special features of this call are requested */ |
| |
| if (fstatat(AT_FDCWD, path, ret_stat, FLAGS_SET(chase_flags, CHASE_NOFOLLOW) ? AT_SYMLINK_NOFOLLOW : 0) < 0) |
| return -errno; |
| |
| return 1; |
| } |
| |
| r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
| if (r < 0) |
| return r; |
| assert(path_fd >= 0); |
| |
| if (fstat(path_fd, ret_stat) < 0) |
| return -errno; |
| |
| if (ret_path) |
| *ret_path = TAKE_PTR(p); |
| if (ret_fd) |
| *ret_fd = TAKE_FD(path_fd); |
| |
| return 1; |
| } |
| |
| int chase_symlinks_and_access( |
| const char *path, |
| const char *root, |
| ChaseSymlinksFlags chase_flags, |
| int access_mode, |
| char **ret_path, |
| int *ret_fd) { |
| |
| _cleanup_close_ int path_fd = -EBADF; |
| _cleanup_free_ char *p = NULL; |
| int r; |
| |
| assert(path); |
| |
| if (chase_flags & (CHASE_NONEXISTENT|CHASE_STEP)) |
| return -EINVAL; |
| |
| if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0 && !ret_fd) { |
| /* Shortcut this call if none of the special features of this call are requested */ |
| |
| if (faccessat(AT_FDCWD, path, access_mode, FLAGS_SET(chase_flags, CHASE_NOFOLLOW) ? AT_SYMLINK_NOFOLLOW : 0) < 0) |
| return -errno; |
| |
| return 1; |
| } |
| |
| r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd); |
| if (r < 0) |
| return r; |
| assert(path_fd >= 0); |
| |
| r = access_fd(path_fd, access_mode); |
| if (r < 0) |
| return r; |
| |
| if (ret_path) |
| *ret_path = TAKE_PTR(p); |
| if (ret_fd) |
| *ret_fd = TAKE_FD(path_fd); |
| |
| return 1; |
| } |
| |
| int chase_symlinks_and_fopen_unlocked( |
| const char *path, |
| const char *root, |
| ChaseSymlinksFlags chase_flags, |
| const char *open_flags, |
| char **ret_path, |
| FILE **ret_file) { |
| |
| _cleanup_free_ char *final_path = NULL; |
| _cleanup_close_ int fd = -EBADF; |
| int mode_flags, r; |
| |
| assert(path); |
| assert(open_flags); |
| assert(ret_file); |
| |
| mode_flags = fopen_mode_to_flags(open_flags); |
| if (mode_flags < 0) |
| return mode_flags; |
| |
| fd = chase_symlinks_and_open(path, root, chase_flags, mode_flags, ret_path ? &final_path : NULL); |
| if (fd < 0) |
| return fd; |
| |
| r = take_fdopen_unlocked(&fd, open_flags, ret_file); |
| if (r < 0) |
| return r; |
| |
| if (ret_path) |
| *ret_path = TAKE_PTR(final_path); |
| |
| return 0; |
| } |
| |
| int chase_symlinks_and_unlink( |
| const char *path, |
| const char *root, |
| ChaseSymlinksFlags chase_flags, |
| int unlink_flags, |
| char **ret_path) { |
| |
| _cleanup_free_ char *p = NULL, *rp = NULL, *dir = NULL, *fname = NULL; |
| _cleanup_close_ int fd = -1; |
| int r; |
| |
| assert(path); |
| |
| r = path_extract_directory(path, &dir); |
| if (r < 0) |
| return r; |
| r = path_extract_filename(path, &fname); |
| if (r < 0) |
| return r; |
| |
| fd = chase_symlinks_and_open(dir, root, chase_flags, O_PATH|O_DIRECTORY|O_CLOEXEC, ret_path ? &p : NULL); |
| if (fd < 0) |
| return fd; |
| |
| if (p) { |
| rp = path_join(p, fname); |
| if (!rp) |
| return -ENOMEM; |
| } |
| |
| if (unlinkat(fd, fname, unlink_flags) < 0) |
| return -errno; |
| |
| if (ret_path) |
| *ret_path = TAKE_PTR(rp); |
| |
| return 0; |
| } |
