X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fbasic%2Ffs-util.c;h=4d494650cb916cfcd3fa697cb2884449d44f331a;hp=ba79a329daa994dfa56a853a0df490b59d7d8f45;hb=4a7059686430f596810f0c83e4897154828fd352;hpb=da2587d5154e11d4e643e326793f3ce2cc48dee6
diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index ba79a329d..4d494650c 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -1,5 +1,3 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
/***
This file is part of systemd.
@@ -19,16 +17,30 @@
along with systemd; If not, see .
***/
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
#include "alloc-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
+//#include "log.h"
+//#include "macro.h"
+//#include "missing.h"
#include "mkdir.h"
#include "parse-util.h"
#include "path-util.h"
#include "string-util.h"
#include "strv.h"
+//#include "time-util.h"
#include "user-util.h"
#include "util.h"
@@ -213,25 +225,25 @@ int readlink_and_make_absolute(const char *p, char **r) {
return 0;
}
-int readlink_and_canonicalize(const char *p, char **r) {
+int readlink_and_canonicalize(const char *p, const char *root, char **ret) {
char *t, *s;
- int j;
+ int r;
assert(p);
- assert(r);
+ assert(ret);
- j = readlink_and_make_absolute(p, &t);
- if (j < 0)
- return j;
+ r = readlink_and_make_absolute(p, &t);
+ if (r < 0)
+ return r;
- s = canonicalize_file_name(t);
- if (s) {
+ r = chase_symlinks(t, root, 0, &s);
+ if (r < 0)
+ /* If we can't follow up, then let's return the original string, slightly cleaned up. */
+ *ret = path_kill_slashes(t);
+ else {
+ *ret = s;
free(t);
- *r = s;
- } else
- *r = t;
-
- path_kill_slashes(*r);
+ }
return 0;
}
@@ -275,26 +287,6 @@ int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
return 0;
}
-#if 0 /// UNNEEDED by elogind
-int fchmod_and_fchown(int fd, mode_t mode, uid_t uid, gid_t gid) {
- assert(fd >= 0);
-
- /* 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;
-}
-#endif // 0
-
int fchmod_umask(int fd, mode_t m) {
mode_t u;
int r;
@@ -333,7 +325,8 @@ int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gi
if (parents)
mkdir_parents(path, 0755);
- fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode > 0 ? mode : 0644);
+ fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY,
+ (mode == 0 || mode == MODE_INVALID) ? 0644 : mode);
if (fd < 0)
return -errno;
@@ -475,7 +468,7 @@ int get_files_in_directory(const char *path, char ***list) {
errno = 0;
de = readdir(d);
- if (!de && errno != 0)
+ if (!de && errno > 0)
return -errno;
if (!de)
break;
@@ -506,3 +499,323 @@ int get_files_in_directory(const char *path, char ***list) {
return n;
}
+
+#if 0 /// UNNEEDED by elogind
+static int getenv_tmp_dir(const char **ret_path) {
+ const char *n;
+ int r, ret = 0;
+
+ assert(ret_path);
+
+ /* We use the same order of environment variables python uses in tempfile.gettempdir():
+ * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
+ FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") {
+ const char *e;
+
+ e = secure_getenv(n);
+ if (!e)
+ continue;
+ if (!path_is_absolute(e)) {
+ r = -ENOTDIR;
+ goto next;
+ }
+ if (!path_is_safe(e)) {
+ r = -EPERM;
+ goto next;
+ }
+
+ r = is_dir(e, true);
+ if (r < 0)
+ goto next;
+ if (r == 0) {
+ r = -ENOTDIR;
+ goto next;
+ }
+
+ *ret_path = e;
+ return 1;
+
+ next:
+ /* Remember first error, to make this more debuggable */
+ if (ret >= 0)
+ ret = r;
+ }
+
+ if (ret < 0)
+ return ret;
+
+ *ret_path = NULL;
+ return ret;
+}
+
+static int tmp_dir_internal(const char *def, const char **ret) {
+ const char *e;
+ int r, k;
+
+ assert(def);
+ assert(ret);
+
+ r = getenv_tmp_dir(&e);
+ if (r > 0) {
+ *ret = e;
+ return 0;
+ }
+
+ k = is_dir(def, true);
+ if (k == 0)
+ k = -ENOTDIR;
+ if (k < 0)
+ return r < 0 ? r : k;
+
+ *ret = def;
+ return 0;
+}
+
+int var_tmp_dir(const char **ret) {
+
+ /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
+ * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
+ * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
+ * making it a variable that overrides all temporary file storage locations. */
+
+ return tmp_dir_internal("/var/tmp", ret);
+}
+
+int tmp_dir(const char **ret) {
+
+ /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
+ * backed by an in-memory file system: /tmp. */
+
+ return tmp_dir_internal("/tmp", ret);
+}
+
+int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
+ char path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
+ int r;
+
+ /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
+ xsprintf(path, "/proc/self/fd/%i", what);
+
+ r = inotify_add_watch(fd, path, mask);
+ if (r < 0)
+ return -errno;
+
+ return r;
+}
+
+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 */
+ bool exists = true;
+ char *todo;
+ int r;
+
+ assert(path);
+
+ /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
+ * symlinks relative to a root directory, instead of the root of the host.
+ *
+ * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
+ * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
+ * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
+ * prefixed accordingly.
+ *
+ * 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 it's special meaning
+ * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no
+ * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races
+ * at 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 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.
+ *
+ * Note: there's also chase_symlinks_prefix() (see below), which as first step prefixes the passed path by the
+ * passed root. */
+
+ if (original_root) {
+ r = path_make_absolute_cwd(original_root, &root);
+ if (r < 0)
+ return r;
+
+ if (flags & CHASE_PREFIX_ROOT)
+ path = prefix_roota(root, path);
+ }
+
+ r = path_make_absolute_cwd(path, &buffer);
+ if (r < 0)
+ return r;
+
+ fd = open("/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
+ if (fd < 0)
+ return -errno;
+
+ todo = buffer;
+ for (;;) {
+ _cleanup_free_ char *first = NULL;
+ _cleanup_close_ int child = -1;
+ struct stat st;
+ size_t n, m;
+
+ /* Determine length of first component in the path */
+ n = strspn(todo, "/"); /* The slashes */
+ m = n + strcspn(todo + n, "/"); /* The entire length of the component */
+
+ /* Extract the first component. */
+ first = strndup(todo, m);
+ if (!first)
+ return -ENOMEM;
+
+ todo += m;
+
+ /* Just a single slash? Then we reached the end. */
+ if (isempty(first) || path_equal(first, "/"))
+ break;
+
+ /* Just a dot? Then let's eat this up. */
+ if (path_equal(first, "/."))
+ continue;
+
+ /* Two dots? Then chop off the last bit of what we already found out. */
+ if (path_equal(first, "/..")) {
+ _cleanup_free_ char *parent = NULL;
+ int fd_parent = -1;
+
+ /* 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, "/"))
+ continue;
+
+ parent = dirname_malloc(done);
+ if (!parent)
+ return -ENOMEM;
+
+ /* Don't allow this to leave the root dir. */
+ if (root &&
+ path_startswith(done, root) &&
+ !path_startswith(parent, root))
+ continue;
+
+ free_and_replace(done, parent);
+
+ fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH);
+ if (fd_parent < 0)
+ return -errno;
+
+ safe_close(fd);
+ fd = fd_parent;
+
+ continue;
+ }
+
+ /* Otherwise let's see what this is. */
+ child = openat(fd, first + n, 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 "./"
+ * or something else weird. */
+
+ if (!strextend(&done, first, todo, NULL))
+ return -ENOMEM;
+
+ exists = false;
+ break;
+ }
+
+ return -errno;
+ }
+
+ if (fstat(child, &st) < 0)
+ return -errno;
+
+ if (S_ISLNK(st.st_mode)) {
+ _cleanup_free_ char *destination = NULL;
+
+ /* 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 + n, &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
+ * directory as base. */
+
+ safe_close(fd);
+ fd = open(root ?: "/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
+ if (fd < 0)
+ return -errno;
+
+ free_and_replace(buffer, destination);
+
+ todo = buffer;
+ free(done);
+
+ /* Note that we do not revalidate the root, we take it as is. */
+ if (isempty(root))
+ done = NULL;
+ else {
+ done = strdup(root);
+ if (!done)
+ return -ENOMEM;
+ }
+
+ } else {
+ char *joined;
+
+ /* A relative destination. If so, this is what we'll prefix what's left to do with what
+ * we just read, and start the loop again, but remain in the current directory. */
+
+ joined = strjoin("/", destination, todo);
+ if (!joined)
+ return -ENOMEM;
+
+ free(buffer);
+ todo = buffer = joined;
+ }
+
+ continue;
+ }
+
+ /* If this is not a symlink, then let's just add the name we read to what we already verified. */
+ if (!done) {
+ done = first;
+ first = NULL;
+ } else {
+ if (!strextend(&done, first, NULL))
+ return -ENOMEM;
+ }
+
+ /* And iterate again, but go one directory further down. */
+ safe_close(fd);
+ fd = child;
+ child = -1;
+ }
+
+ if (!done) {
+ /* Special case, turn the empty string into "/", to indicate the root directory. */
+ done = strdup("/");
+ if (!done)
+ return -ENOMEM;
+ }
+
+ *ret = done;
+ done = NULL;
+
+ return exists;
+}
+#endif // 0