]> git.ipfire.org Git - thirdparty/systemd.git/blob - src/core/mount-setup.c
util: make time formatting a bit smarter
[thirdparty/systemd.git] / src / core / mount-setup.c
1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2
3 /***
4 This file is part of systemd.
5
6 Copyright 2010 Lennart Poettering
7
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
12
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 Lesser General Public License for more details.
17
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 ***/
21
22 #include <sys/mount.h>
23 #include <errno.h>
24 #include <sys/stat.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <libgen.h>
28 #include <assert.h>
29 #include <unistd.h>
30 #include <ftw.h>
31
32 #include "mount-setup.h"
33 #include "dev-setup.h"
34 #include "log.h"
35 #include "macro.h"
36 #include "util.h"
37 #include "label.h"
38 #include "set.h"
39 #include "strv.h"
40 #include "mkdir.h"
41 #include "path-util.h"
42 #include "missing.h"
43 #include "virt.h"
44 #include "efivars.h"
45
46 #ifndef TTY_GID
47 #define TTY_GID 5
48 #endif
49
50 typedef enum MountMode {
51 MNT_NONE = 0,
52 MNT_FATAL = 1 << 0,
53 MNT_IN_CONTAINER = 1 << 1,
54 } MountMode;
55
56 typedef struct MountPoint {
57 const char *what;
58 const char *where;
59 const char *type;
60 const char *options;
61 unsigned long flags;
62 bool (*condition_fn)(void);
63 MountMode mode;
64 } MountPoint;
65
66 /* The first three entries we might need before SELinux is up. The
67 * fourth (securityfs) is needed by IMA to load a custom policy. The
68 * other ones we can delay until SELinux and IMA are loaded. */
69 #define N_EARLY_MOUNT 5
70
71 static const MountPoint mount_table[] = {
72 { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
73 NULL, MNT_FATAL|MNT_IN_CONTAINER },
74 { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
75 NULL, MNT_FATAL|MNT_IN_CONTAINER },
76 { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME,
77 NULL, MNT_FATAL|MNT_IN_CONTAINER },
78 { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
79 NULL, MNT_NONE },
80 { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
81 NULL, MNT_NONE },
82 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
83 NULL, MNT_FATAL|MNT_IN_CONTAINER },
84 { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC,
85 NULL, MNT_IN_CONTAINER },
86 { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
87 NULL, MNT_FATAL|MNT_IN_CONTAINER },
88 { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
89 NULL, MNT_IN_CONTAINER },
90 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV,
91 NULL, MNT_IN_CONTAINER },
92 { "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
93 NULL, MNT_NONE },
94 #ifdef ENABLE_EFI
95 { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
96 is_efi_boot, MNT_NONE },
97 #endif
98 };
99
100 /* These are API file systems that might be mounted by other software,
101 * we just list them here so that we know that we should ignore them */
102
103 static const char ignore_paths[] =
104 /* SELinux file systems */
105 "/sys/fs/selinux\0"
106 "/selinux\0"
107 /* Legacy cgroup mount points */
108 "/dev/cgroup\0"
109 "/cgroup\0"
110 /* Legacy kernel file system */
111 "/proc/bus/usb\0"
112 /* Container bind mounts */
113 "/proc/sys\0"
114 "/dev/console\0"
115 "/proc/kmsg\0";
116
117 bool mount_point_is_api(const char *path) {
118 unsigned i;
119
120 /* Checks if this mount point is considered "API", and hence
121 * should be ignored */
122
123 for (i = 0; i < ELEMENTSOF(mount_table); i ++)
124 if (path_equal(path, mount_table[i].where))
125 return true;
126
127 return path_startswith(path, "/sys/fs/cgroup/");
128 }
129
130 bool mount_point_ignore(const char *path) {
131 const char *i;
132
133 NULSTR_FOREACH(i, ignore_paths)
134 if (path_equal(path, i))
135 return true;
136
137 return false;
138 }
139
140 static int mount_one(const MountPoint *p, bool relabel) {
141 int r;
142
143 assert(p);
144
145 if (p->condition_fn && !p->condition_fn())
146 return 0;
147
148 /* Relabel first, just in case */
149 if (relabel)
150 label_fix(p->where, true, true);
151
152 r = path_is_mount_point(p->where, true);
153 if (r < 0)
154 return r;
155
156 if (r > 0)
157 return 0;
158
159 /* Skip securityfs in a container */
160 if (!(p->mode & MNT_IN_CONTAINER) && detect_container(NULL) > 0)
161 return 0;
162
163 /* The access mode here doesn't really matter too much, since
164 * the mounted file system will take precedence anyway. */
165 mkdir_p_label(p->where, 0755);
166
167 log_debug("Mounting %s to %s of type %s with options %s.",
168 p->what,
169 p->where,
170 p->type,
171 strna(p->options));
172
173 if (mount(p->what,
174 p->where,
175 p->type,
176 p->flags,
177 p->options) < 0) {
178 log_full((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, "Failed to mount %s: %s", p->where, strerror(errno));
179 return (p->mode & MNT_FATAL) ? -errno : 0;
180 }
181
182 /* Relabel again, since we now mounted something fresh here */
183 if (relabel)
184 label_fix(p->where, false, false);
185
186 return 1;
187 }
188
189 int mount_setup_early(void) {
190 unsigned i;
191 int r = 0;
192
193 assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table));
194
195 /* Do a minimal mount of /proc and friends to enable the most
196 * basic stuff, such as SELinux */
197 for (i = 0; i < N_EARLY_MOUNT; i ++) {
198 int j;
199
200 j = mount_one(mount_table + i, false);
201 if (r == 0)
202 r = j;
203 }
204
205 return r;
206 }
207
208 int mount_cgroup_controllers(char ***join_controllers) {
209 int r;
210 FILE *f;
211 char buf[LINE_MAX];
212 Set *controllers;
213
214 /* Mount all available cgroup controllers that are built into the kernel. */
215
216 f = fopen("/proc/cgroups", "re");
217 if (!f) {
218 log_error("Failed to enumerate cgroup controllers: %m");
219 return 0;
220 }
221
222 controllers = set_new(string_hash_func, string_compare_func);
223 if (!controllers) {
224 r = log_oom();
225 goto finish;
226 }
227
228 /* Ignore the header line */
229 (void) fgets(buf, sizeof(buf), f);
230
231 for (;;) {
232 char *controller;
233 int enabled = 0;
234
235 if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
236
237 if (feof(f))
238 break;
239
240 log_error("Failed to parse /proc/cgroups.");
241 r = -EIO;
242 goto finish;
243 }
244
245 if (!enabled) {
246 free(controller);
247 continue;
248 }
249
250 r = set_put(controllers, controller);
251 if (r < 0) {
252 log_error("Failed to add controller to set.");
253 free(controller);
254 goto finish;
255 }
256 }
257
258 for (;;) {
259 MountPoint p;
260 char *controller, *where, *options;
261 char ***k = NULL;
262
263 controller = set_steal_first(controllers);
264 if (!controller)
265 break;
266
267 if (join_controllers)
268 for (k = join_controllers; *k; k++)
269 if (strv_find(*k, controller))
270 break;
271
272 if (k && *k) {
273 char **i, **j;
274
275 for (i = *k, j = *k; *i; i++) {
276
277 if (!streq(*i, controller)) {
278 char *t;
279
280 t = set_remove(controllers, *i);
281 if (!t) {
282 free(*i);
283 continue;
284 }
285 free(t);
286 }
287
288 *(j++) = *i;
289 }
290
291 *j = NULL;
292
293 options = strv_join(*k, ",");
294 if (!options) {
295 free(controller);
296 r = log_oom();
297 goto finish;
298 }
299
300 } else {
301 options = controller;
302 controller = NULL;
303 }
304
305 where = strappend("/sys/fs/cgroup/", options);
306 if (!where) {
307 free(options);
308 r = log_oom();
309 goto finish;
310 }
311
312 zero(p);
313 p.what = "cgroup";
314 p.where = where;
315 p.type = "cgroup";
316 p.options = options;
317 p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV;
318 p.mode = MNT_IN_CONTAINER;
319
320 r = mount_one(&p, true);
321 free(controller);
322 free(where);
323
324 if (r < 0) {
325 free(options);
326 goto finish;
327 }
328
329 if (r > 0 && k && *k) {
330 char **i;
331
332 for (i = *k; *i; i++) {
333 char *t;
334
335 t = strappend("/sys/fs/cgroup/", *i);
336 if (!t) {
337 r = log_oom();
338 free(options);
339 goto finish;
340 }
341
342 r = symlink(options, t);
343 free(t);
344
345 if (r < 0 && errno != EEXIST) {
346 log_error("Failed to create symlink: %m");
347 r = -errno;
348 free(options);
349 goto finish;
350 }
351 }
352 }
353
354 free(options);
355 }
356
357 r = 0;
358
359 finish:
360 set_free_free(controllers);
361
362 fclose(f);
363
364 return r;
365 }
366
367 static int nftw_cb(
368 const char *fpath,
369 const struct stat *sb,
370 int tflag,
371 struct FTW *ftwbuf) {
372
373 /* No need to label /dev twice in a row... */
374 if (_unlikely_(ftwbuf->level == 0))
375 return FTW_CONTINUE;
376
377 label_fix(fpath, false, false);
378
379 /* /run/initramfs is static data and big, no need to
380 * dynamically relabel its contents at boot... */
381 if (_unlikely_(ftwbuf->level == 1 &&
382 tflag == FTW_D &&
383 streq(fpath, "/run/initramfs")))
384 return FTW_SKIP_SUBTREE;
385
386 return FTW_CONTINUE;
387 };
388
389 int mount_setup(bool loaded_policy) {
390
391 static const char relabel[] =
392 "/run/initramfs/root-fsck\0"
393 "/run/initramfs/shutdown\0";
394
395 int r;
396 unsigned i;
397 const char *j;
398
399 for (i = 0; i < ELEMENTSOF(mount_table); i ++) {
400 r = mount_one(mount_table + i, true);
401
402 if (r < 0)
403 return r;
404 }
405
406 /* Nodes in devtmpfs and /run need to be manually updated for
407 * the appropriate labels, after mounting. The other virtual
408 * API file systems like /sys and /proc do not need that, they
409 * use the same label for all their files. */
410 if (loaded_policy) {
411 usec_t before_relabel, after_relabel;
412 char timespan[FORMAT_TIMESPAN_MAX];
413
414 before_relabel = now(CLOCK_MONOTONIC);
415
416 nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
417 nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
418
419 /* Explicitly relabel these */
420 NULSTR_FOREACH(j, relabel)
421 label_fix(j, true, false);
422
423 after_relabel = now(CLOCK_MONOTONIC);
424
425 log_info("Relabelled /dev and /run in %s.",
426 format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel, 0));
427 }
428
429 /* Create a few default symlinks, which are normally created
430 * by udevd, but some scripts might need them before we start
431 * udevd. */
432 dev_setup(NULL);
433
434 /* Mark the root directory as shared in regards to mount
435 * propagation. The kernel defaults to "private", but we think
436 * it makes more sense to have a default of "shared" so that
437 * nspawn and the container tools work out of the box. If
438 * specific setups need other settings they can reset the
439 * propagation mode to private if needed. */
440 if (detect_container(NULL) <= 0)
441 if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0)
442 log_warning("Failed to set up the root directory for shared mount propagation: %m");
443
444 /* Create a few directories we always want around, Note that
445 * sd_booted() checks for /run/systemd/system, so this mkdir
446 * really needs to stay for good, otherwise software that
447 * copied sd-daemon.c into their sources will misdetect
448 * systemd. */
449 mkdir_label("/run/systemd", 0755);
450 mkdir_label("/run/systemd/system", 0755);
451 mkdir_label("/run/systemd/inaccessible", 0000);
452
453 return 0;
454 }