2 This file is part of systemd.
4 Copyright 2010 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 #include <sys/mount.h>
26 #include "alloc-util.h"
28 #include "cgroup-util.h"
29 #include "dev-setup.h"
37 #include "mount-setup.h"
38 #include "mount-util.h"
39 #include "path-util.h"
41 #include "smack-util.h"
43 #include "user-util.h"
47 typedef enum MountMode
{
50 MNT_IN_CONTAINER
= 1 << 1,
53 typedef struct MountPoint
{
59 bool (*condition_fn
)(void);
63 /* The first three entries we might need before SELinux is up. The
64 * fourth (securityfs) is needed by IMA to load a custom policy. The
65 * other ones we can delay until SELinux and IMA are loaded. When
66 * SMACK is enabled we need smackfs, too, so it's a fifth one. */
68 #define N_EARLY_MOUNT 5
70 #define N_EARLY_MOUNT 4
73 static const MountPoint mount_table
[] = {
74 { "sysfs", "/sys", "sysfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
75 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
76 { "proc", "/proc", "proc", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
77 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
78 { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID
|MS_STRICTATIME
,
79 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
80 { "securityfs", "/sys/kernel/security", "securityfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
83 { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
84 mac_smack_use
, MNT_FATAL
},
85 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
86 mac_smack_use
, MNT_FATAL
},
88 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
89 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
90 { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID
), MS_NOSUID
|MS_NOEXEC
,
91 NULL
, MNT_IN_CONTAINER
},
93 { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
94 mac_smack_use
, MNT_FATAL
},
96 { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
97 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
98 { "cgroup", "/sys/fs/cgroup", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
99 cg_is_unified_wanted
, MNT_IN_CONTAINER
},
100 { "cgroup", "/sys/fs/cgroup", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
101 cg_is_unified_wanted
, MNT_IN_CONTAINER
},
102 { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
,
103 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
104 { "cgroup", "/sys/fs/cgroup/unified", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
105 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
},
106 { "cgroup", "/sys/fs/cgroup/unified", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
107 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
},
108 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
109 cg_is_legacy_wanted
, MNT_IN_CONTAINER
},
110 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
111 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
112 { "pstore", "/sys/fs/pstore", "pstore", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
115 { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
116 is_efi_boot
, MNT_NONE
},
120 /* These are API file systems that might be mounted by other software,
121 * we just list them here so that we know that we should ignore them */
123 static const char ignore_paths
[] =
124 /* SELinux file systems */
126 /* Container bind mounts */
131 bool mount_point_is_api(const char *path
) {
134 /* Checks if this mount point is considered "API", and hence
135 * should be ignored */
137 for (i
= 0; i
< ELEMENTSOF(mount_table
); i
++)
138 if (path_equal(path
, mount_table
[i
].where
))
141 return path_startswith(path
, "/sys/fs/cgroup/");
144 bool mount_point_ignore(const char *path
) {
147 NULSTR_FOREACH(i
, ignore_paths
)
148 if (path_equal(path
, i
))
154 static int mount_one(const MountPoint
*p
, bool relabel
) {
159 if (p
->condition_fn
&& !p
->condition_fn())
162 /* Relabel first, just in case */
164 (void) label_fix(p
->where
, true, true);
166 r
= path_is_mount_point(p
->where
, NULL
, AT_SYMLINK_FOLLOW
);
167 if (r
< 0 && r
!= -ENOENT
) {
168 log_full_errno((p
->mode
& MNT_FATAL
) ? LOG_ERR
: LOG_DEBUG
, r
, "Failed to determine whether %s is a mount point: %m", p
->where
);
169 return (p
->mode
& MNT_FATAL
) ? r
: 0;
174 /* Skip securityfs in a container */
175 if (!(p
->mode
& MNT_IN_CONTAINER
) && detect_container() > 0)
178 /* The access mode here doesn't really matter too much, since
179 * the mounted file system will take precedence anyway. */
181 (void) mkdir_p_label(p
->where
, 0755);
183 (void) mkdir_p(p
->where
, 0755);
185 log_debug("Mounting %s to %s of type %s with options %s.",
196 log_full_errno((p
->mode
& MNT_FATAL
) ? LOG_ERR
: LOG_DEBUG
, errno
, "Failed to mount %s at %s: %m", p
->type
, p
->where
);
197 return (p
->mode
& MNT_FATAL
) ? -errno
: 0;
200 /* Relabel again, since we now mounted something fresh here */
202 (void) label_fix(p
->where
, false, false);
207 static int mount_points_setup(unsigned n
, bool loaded_policy
) {
211 for (i
= 0; i
< n
; i
++) {
214 j
= mount_one(mount_table
+ i
, loaded_policy
);
215 if (j
!= 0 && r
>= 0)
222 int mount_setup_early(void) {
223 assert_cc(N_EARLY_MOUNT
<= ELEMENTSOF(mount_table
));
225 /* Do a minimal mount of /proc and friends to enable the most
226 * basic stuff, such as SELinux */
227 return mount_points_setup(N_EARLY_MOUNT
, false);
230 int mount_cgroup_controllers(char ***join_controllers
) {
231 _cleanup_set_free_free_ Set
*controllers
= NULL
;
234 if (!cg_is_legacy_wanted())
237 /* Mount all available cgroup controllers that are built into the kernel. */
239 controllers
= set_new(&string_hash_ops
);
243 r
= cg_kernel_controllers(controllers
);
245 return log_error_errno(r
, "Failed to enumerate cgroup controllers: %m");
248 _cleanup_free_
char *options
= NULL
, *controller
= NULL
, *where
= NULL
;
252 .flags
= MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
253 .mode
= MNT_IN_CONTAINER
,
257 controller
= set_steal_first(controllers
);
261 if (join_controllers
)
262 for (k
= join_controllers
; *k
; k
++)
263 if (strv_find(*k
, controller
))
269 for (i
= *k
, j
= *k
; *i
; i
++) {
271 if (!streq(*i
, controller
)) {
272 _cleanup_free_
char *t
;
274 t
= set_remove(controllers
, *i
);
286 options
= strv_join(*k
, ",");
290 options
= controller
;
294 where
= strappend("/sys/fs/cgroup/", options
);
301 r
= mount_one(&p
, true);
305 if (r
> 0 && k
&& *k
) {
308 for (i
= *k
; *i
; i
++) {
309 _cleanup_free_
char *t
= NULL
;
311 t
= strappend("/sys/fs/cgroup/", *i
);
315 r
= symlink(options
, t
);
317 #ifdef SMACK_RUN_LABEL
318 _cleanup_free_
char *src
;
319 src
= strappend("/sys/fs/cgroup/", options
);
322 r
= mac_smack_copy(t
, src
);
323 if (r
< 0 && r
!= -EOPNOTSUPP
)
324 return log_error_errno(r
, "Failed to copy smack label from %s to %s: %m", src
, t
);
326 } else if (errno
!= EEXIST
)
327 return log_error_errno(errno
, "Failed to create symlink %s: %m", t
);
332 /* Now that we mounted everything, let's make the tmpfs the
333 * cgroup file systems are mounted into read-only. */
334 (void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT
|MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
|MS_RDONLY
, "mode=755");
339 #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
342 const struct stat
*sb
,
344 struct FTW
*ftwbuf
) {
346 /* No need to label /dev twice in a row... */
347 if (_unlikely_(ftwbuf
->level
== 0))
350 label_fix(fpath
, false, false);
352 /* /run/initramfs is static data and big, no need to
353 * dynamically relabel its contents at boot... */
354 if (_unlikely_(ftwbuf
->level
== 1 &&
356 streq(fpath
, "/run/initramfs")))
357 return FTW_SKIP_SUBTREE
;
363 int mount_setup(bool loaded_policy
) {
366 r
= mount_points_setup(ELEMENTSOF(mount_table
), loaded_policy
);
370 #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
371 /* Nodes in devtmpfs and /run need to be manually updated for
372 * the appropriate labels, after mounting. The other virtual
373 * API file systems like /sys and /proc do not need that, they
374 * use the same label for all their files. */
376 usec_t before_relabel
, after_relabel
;
377 char timespan
[FORMAT_TIMESPAN_MAX
];
379 before_relabel
= now(CLOCK_MONOTONIC
);
381 nftw("/dev", nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
382 nftw("/dev/shm", nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
383 nftw("/run", nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
385 after_relabel
= now(CLOCK_MONOTONIC
);
387 log_info("Relabelled /dev and /run in %s.",
388 format_timespan(timespan
, sizeof(timespan
), after_relabel
- before_relabel
, 0));
392 /* Create a few default symlinks, which are normally created
393 * by udevd, but some scripts might need them before we start
395 dev_setup(NULL
, UID_INVALID
, GID_INVALID
);
397 /* Mark the root directory as shared in regards to mount propagation. The kernel defaults to "private", but we
398 * think it makes more sense to have a default of "shared" so that nspawn and the container tools work out of
399 * the box. If specific setups need other settings they can reset the propagation mode to private if
400 * needed. Note that we set this only when we are invoked directly by the kernel. If we are invoked by a
401 * container manager we assume the container manager knows what it is doing (for example, because it set up
402 * some directories with different propagation modes). */
403 if (detect_container() <= 0)
404 if (mount(NULL
, "/", NULL
, MS_REC
|MS_SHARED
, NULL
) < 0)
405 log_warning_errno(errno
, "Failed to set up the root directory for shared mount propagation: %m");
407 /* Create a few directories we always want around, Note that sd_booted() checks for /run/systemd/system, so
408 * this mkdir really needs to stay for good, otherwise software that copied sd-daemon.c into their sources will
409 * misdetect systemd. */
410 (void) mkdir_label("/run/systemd", 0755);
411 (void) mkdir_label("/run/systemd/system", 0755);
413 /* Set up inaccessible items */
414 (void) mkdir_label("/run/systemd/inaccessible", 0000);
415 (void) mknod("/run/systemd/inaccessible/reg", S_IFREG
| 0000, 0);
416 (void) mkdir_label("/run/systemd/inaccessible/dir", 0000);
417 (void) mknod("/run/systemd/inaccessible/chr", S_IFCHR
| 0000, makedev(0, 0));
418 (void) mknod("/run/systemd/inaccessible/blk", S_IFBLK
| 0000, makedev(0, 0));
419 (void) mkfifo("/run/systemd/inaccessible/fifo", 0000);
420 (void) mknod("/run/systemd/inaccessible/sock", S_IFSOCK
| 0000, 0);