1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <sys/mount.h>
32 #include "mount-setup.h"
45 typedef struct MountPoint {
54 /* The first three entries we might need before SELinux is up. The
55 * fourth (securityfs) is needed by IMA to load a custom policy. The
56 * other ones we can delay until SELinux and IMA are loaded. */
57 #define N_EARLY_MOUNT 4
59 static const MountPoint mount_table[] = {
60 { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
61 { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
62 { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID, true },
63 { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false },
64 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV, true },
65 { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, false },
66 { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV, true },
67 { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, false },
68 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, false },
71 /* These are API file systems that might be mounted by other software,
72 * we just list them here so that we know that we should ignore them */
74 static const char * const ignore_paths[] = {
80 bool mount_point_is_api(const char *path) {
83 /* Checks if this mount point is considered "API", and hence
84 * should be ignored */
86 for (i = 0; i < ELEMENTSOF(mount_table); i ++)
87 if (path_equal(path, mount_table[i].where))
90 return path_startswith(path, "/sys/fs/cgroup/");
93 bool mount_point_ignore(const char *path) {
96 for (i = 0; i < ELEMENTSOF(ignore_paths); i++)
97 if (path_equal(path, ignore_paths[i]))
103 static int mount_one(const MountPoint *p, bool relabel) {
108 /* Relabel first, just in case */
110 label_fix(p->where, true);
112 if ((r = path_is_mount_point(p->where, true)) < 0)
118 /* The access mode here doesn't really matter too much, since
119 * the mounted file system will take precedence anyway. */
120 mkdir_p(p->where, 0755);
122 log_debug("Mounting %s to %s of type %s with options %s.",
133 log_error("Failed to mount %s: %s", p->where, strerror(errno));
134 return p->fatal ? -errno : 0;
137 /* Relabel again, since we now mounted something fresh here */
139 label_fix(p->where, false);
144 int mount_setup_early(void) {
148 assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table));
150 /* Do a minimal mount of /proc and friends to enable the most
151 * basic stuff, such as SELinux */
152 for (i = 0; i < N_EARLY_MOUNT; i ++) {
155 j = mount_one(mount_table + i, false);
163 int mount_cgroup_controllers(char ***join_controllers) {
169 /* Mount all available cgroup controllers that are built into the kernel. */
171 f = fopen("/proc/cgroups", "re");
173 log_error("Failed to enumerate cgroup controllers: %m");
177 controllers = set_new(string_hash_func, string_compare_func);
180 log_error("Failed to allocate controller set.");
184 /* Ignore the header line */
185 (void) fgets(buf, sizeof(buf), f);
191 if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
196 log_error("Failed to parse /proc/cgroups.");
206 r = set_put(controllers, controller);
208 log_error("Failed to add controller to set.");
216 char *controller, *where, *options;
219 controller = set_steal_first(controllers);
223 if (join_controllers)
224 for (k = join_controllers; *k; k++)
225 if (strv_find(*k, controller))
231 for (i = *k, j = *k; *i; i++) {
233 if (!streq(*i, controller)) {
236 t = set_remove(controllers, *i);
249 options = strv_join(*k, ",");
251 log_error("Failed to join options");
258 options = controller;
262 where = strappend("/sys/fs/cgroup/", options);
264 log_error("Failed to build path");
275 p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV;
278 r = mount_one(&p, true);
287 if (r > 0 && k && *k) {
290 for (i = *k; *i; i++) {
293 t = strappend("/sys/fs/cgroup/", *i);
295 log_error("Failed to build path");
301 r = symlink(options, t);
304 if (r < 0 && errno != EEXIST) {
305 log_error("Failed to create symlink: %m");
319 set_free_free(controllers);
326 static int symlink_and_label(const char *old_path, const char *new_path) {
332 if ((r = label_symlinkfile_set(new_path)) < 0)
335 if (symlink(old_path, new_path) < 0)
345 const struct stat *sb,
347 struct FTW *ftwbuf) {
349 /* No need to label /dev twice in a row... */
350 if (_unlikely_(ftwbuf->level == 0))
353 label_fix(fpath, true);
355 /* /run/initramfs is static data and big, no need to
356 * dynamically relabel its contents at boot... */
357 if (_unlikely_(ftwbuf->level == 1 &&
359 streq(fpath, "/run/initramfs")))
360 return FTW_SKIP_SUBTREE;
365 int mount_setup(bool loaded_policy) {
367 static const char symlinks[] =
368 "/proc/kcore\0" "/dev/core\0"
369 "/proc/self/fd\0" "/dev/fd\0"
370 "/proc/self/fd/0\0" "/dev/stdin\0"
371 "/proc/self/fd/1\0" "/dev/stdout\0"
372 "/proc/self/fd/2\0" "/dev/stderr\0";
374 static const char relabel[] =
375 "/run/initramfs/root-fsck\0"
376 "/run/initramfs/shutdown\0";
382 for (i = 0; i < ELEMENTSOF(mount_table); i ++) {
383 r = mount_one(mount_table + i, true);
389 /* Nodes in devtmpfs and /run need to be manually updated for
390 * the appropriate labels, after mounting. The other virtual
391 * API file systems like /sys and /proc do not need that, they
392 * use the same label for all their files. */
394 usec_t before_relabel, after_relabel;
395 char timespan[FORMAT_TIMESPAN_MAX];
397 before_relabel = now(CLOCK_MONOTONIC);
399 nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
400 nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
402 /* Explicitly relabel these */
403 NULSTR_FOREACH(j, relabel)
406 after_relabel = now(CLOCK_MONOTONIC);
408 log_info("Relabelled /dev and /run in %s.",
409 format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel));
412 /* Create a few default symlinks, which are normally created
413 * by udevd, but some scripts might need them before we start
415 NULSTR_FOREACH_PAIR(j, k, symlinks)
416 symlink_and_label(j, k);
418 /* Create a few directories we always want around */
419 label_mkdir("/run/systemd", 0755);
420 label_mkdir("/run/systemd/system", 0755);