mirror of
https://github.com/morgan9e/systemd
synced 2026-04-15 00:47:10 +09:00
886c078702
This mount option will count HugeTLB memory usage towards the cgroup’s overall memory usage for the memory controller. See https://lore.kernel.org/all/20231006184629.155543-4-nphamcs@gmail.com/T/#u for the patch introducing the new mount option.
551 lines
20 KiB
C
551 lines
20 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <sys/mount.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "conf-files.h"
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#include "dev-setup.h"
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#include "efivars.h"
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#include "errno-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "label-util.h"
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#include "log.h"
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#include "mkdir-label.h"
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#include "mount-setup.h"
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#include "mount-util.h"
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#include "mountpoint-util.h"
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#include "path-util.h"
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#include "recurse-dir.h"
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#include "smack-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "time-util.h"
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#include "virt.h"
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typedef enum MountMode {
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MNT_FATAL = 1 << 0,
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MNT_IN_CONTAINER = 1 << 1,
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MNT_CHECK_WRITABLE = 1 << 2,
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MNT_FOLLOW_SYMLINK = 1 << 3,
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} MountMode;
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typedef struct MountPoint {
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const char *what;
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const char *where;
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const char *type;
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const char *options;
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int (*options_fn)(int priority, const char *type, char **ret);
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unsigned long flags;
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MountMode mode;
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bool (*condition_fn)(void);
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} MountPoint;
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static int cgroupfs_mount_options(int priority, const char *type, char **ret) {
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int r;
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assert(type);
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assert(streq(type, "cgroup2"));
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assert(ret);
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_cleanup_free_ char *opts = NULL;
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FOREACH_STRING(o, "memory_recursiveprot", "memory_hugetlb_accounting") {
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r = mount_option_supported("cgroup2", o, /* value = */ NULL);
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if (r < 0)
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log_full_errno(priority, r, "Failed to determine whether cgroupfs supports '%s' mount option, assuming not: %m", o);
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else if (r == 0)
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log_debug("'%s' not supported by cgroupfs, not using mount option.", o);
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else if (!strextend_with_separator(&opts, ",", o))
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return log_oom_full(priority);
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}
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*ret = TAKE_PTR(opts);
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return 0;
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}
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int mount_cgroupfs(const char *path) {
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int r;
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assert(path);
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/* Mount a separate cgroupfs instance, taking all options we initial set into account. This is
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* especially useful when cgroup namespace is *not* employed, since the kernel overrides all
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* previous options if a new mount is established in initial cgns (c.f.
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* https://github.com/torvalds/linux/blob/b69bb476dee99d564d65d418e9a20acca6f32c3f/kernel/cgroup/cgroup.c#L1984)
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*/
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_cleanup_free_ char *opts = NULL;
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r = cgroupfs_mount_options(LOG_WARNING, "cgroup2", &opts);
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if (r < 0)
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return r;
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/* These options shall be kept in sync with those in mount_table below. */
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if (!strprepend_with_separator(&opts, ",", "nsdelegate"))
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return log_oom();
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return mount_nofollow_verbose(LOG_ERR, "cgroup2", path, "cgroup2", MS_NOSUID|MS_NOEXEC|MS_NODEV, opts);
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}
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static int usrquota_mount_option(int priority, const char *type, char **ret) {
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_cleanup_free_ char *o = NULL;
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int r;
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assert(type);
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assert(ret);
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r = mount_option_supported(type, "usrquota", /* value= */ NULL);
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if (r < 0)
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log_full_errno(priority, r, "Unable to determine whether %s supports 'usrquota' mount option, assuming not: %m", type);
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else if (r == 0)
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log_debug("Not enabling 'usrquota' for '%s' as kernel lacks support for it.", type);
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else {
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o = strdup("usrquota");
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if (!o)
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return log_oom_full(priority);
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}
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*ret = TAKE_PTR(o);
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return 0;
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}
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static const MountPoint mount_table[] = {
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{
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.what = "proc",
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.where = "/proc",
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.type = "proc",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.mode = MNT_FATAL|MNT_IN_CONTAINER|MNT_FOLLOW_SYMLINK,
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},
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{
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.what = "sysfs",
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.where = "/sys",
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.type = "sysfs",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.mode = MNT_FATAL|MNT_IN_CONTAINER,
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},
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{
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.what = "devtmpfs",
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.where = "/dev",
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.type = "devtmpfs",
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.options = "mode=0755" TMPFS_LIMITS_DEV,
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.flags = MS_NOSUID|MS_STRICTATIME,
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.mode = MNT_FATAL|MNT_IN_CONTAINER,
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},
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{
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.what = "securityfs",
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.where = "/sys/kernel/security",
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.type = "securityfs",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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},
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#if ENABLE_SMACK
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{
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.what = "smackfs",
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.where = "/sys/fs/smackfs",
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.type = "smackfs",
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.options = "smackfsdef=*",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.mode = MNT_FATAL,
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.condition_fn = mac_smack_use,
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},
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{
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.what = "tmpfs",
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.where = "/dev/shm",
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.type = "tmpfs",
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.options = "mode=01777,smackfsroot=*",
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.options_fn = usrquota_mount_option,
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.flags = MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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.mode = MNT_FATAL,
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.condition_fn = mac_smack_use,
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},
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#endif
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{
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.what = "tmpfs",
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.where = "/dev/shm",
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.type = "tmpfs",
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.options = "mode=01777",
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.options_fn = usrquota_mount_option,
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.flags = MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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.mode = MNT_FATAL|MNT_IN_CONTAINER,
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},
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{
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.what = "devpts",
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.where = "/dev/pts",
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.type = "devpts",
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.options = "mode=" STRINGIFY(TTY_MODE) ",gid=" STRINGIFY(TTY_GID),
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.flags = MS_NOSUID|MS_NOEXEC,
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.mode = MNT_IN_CONTAINER,
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},
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#if ENABLE_SMACK
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{
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.what = "tmpfs",
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.where = "/run",
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.type = "tmpfs",
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.options = "mode=0755,smackfsroot=*" TMPFS_LIMITS_RUN,
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.flags = MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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.mode = MNT_FATAL,
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.condition_fn = mac_smack_use,
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},
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#endif
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{
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.what = "tmpfs",
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.where = "/run",
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.type = "tmpfs",
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.options = "mode=0755" TMPFS_LIMITS_RUN,
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.flags = MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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.mode = MNT_FATAL|MNT_IN_CONTAINER,
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},
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{
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.what = "cgroup2",
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.where = "/sys/fs/cgroup",
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.type = "cgroup2",
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.options = "nsdelegate",
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.options_fn = cgroupfs_mount_options,
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.mode = MNT_FATAL|MNT_IN_CONTAINER|MNT_CHECK_WRITABLE,
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},
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#if ENABLE_PSTORE
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{
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.what = "pstore",
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.where = "/sys/fs/pstore",
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.type = "pstore",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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},
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#endif
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#if ENABLE_EFI
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{
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.what = "efivarfs",
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.where = "/sys/firmware/efi/efivars",
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.type = "efivarfs",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.condition_fn = is_efi_boot,
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},
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#endif
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{
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.what = "bpf",
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.where = "/sys/fs/bpf",
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.type = "bpf",
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.options = "mode=0700",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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},
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};
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/* The first three entries we might need before SELinux is up. The
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* fourth (securityfs) is needed by IMA to load a custom policy. The
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* other ones we can delay until SELinux and IMA are loaded. When
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* SMACK is enabled we need smackfs, too, so it's a fifth one. */
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#if ENABLE_SMACK
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#define N_EARLY_MOUNT 5
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#else
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#define N_EARLY_MOUNT 4
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#endif
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assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table));
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bool mount_point_is_api(const char *path) {
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/* Checks if this mount point is considered "API", and hence
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* should be ignored */
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FOREACH_ELEMENT(i, mount_table)
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if (path_equal(path, i->where))
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return true;
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return path_startswith(path, "/sys/fs/cgroup/");
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}
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bool mount_point_ignore(const char *path) {
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/* These are API file systems that might be mounted by other software, we just list them here so that
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* we know that we should ignore them. */
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FOREACH_STRING(i,
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/* SELinux file systems */
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"/sys/fs/selinux",
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/* Container bind mounts */
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"/dev/console",
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"/proc/kmsg",
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"/proc/sys",
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"/proc/sys/kernel/random/boot_id")
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if (path_equal(path, i))
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return true;
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if (path_startswith(path, "/run/host")) /* All mounts passed in from the container manager are
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* something we better ignore. */
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return true;
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return false;
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}
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static int mount_one(const MountPoint *p, bool relabel) {
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int r, priority;
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assert(p);
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assert(p->what);
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assert(p->where);
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assert(p->type);
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priority = FLAGS_SET(p->mode, MNT_FATAL) ? LOG_ERR : LOG_DEBUG;
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if (p->condition_fn && !p->condition_fn())
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return 0;
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/* Relabel first, just in case */
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if (relabel)
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(void) label_fix(p->where, LABEL_IGNORE_ENOENT|LABEL_IGNORE_EROFS);
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r = path_is_mount_point_full(p->where, /* root = */ NULL, AT_SYMLINK_FOLLOW);
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if (r < 0 && r != -ENOENT) {
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log_full_errno(priority, r, "Failed to determine whether %s is a mount point: %m", p->where);
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return FLAGS_SET(p->mode, MNT_FATAL) ? r : 0;
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}
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if (r > 0)
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return 0;
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if (!FLAGS_SET(p->mode, MNT_IN_CONTAINER) && detect_container() > 0)
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return 0;
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/* The access mode here doesn't really matter too much, since
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* the mounted file system will take precedence anyway. */
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if (relabel)
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(void) mkdir_p_label(p->where, 0755);
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else
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(void) mkdir_p(p->where, 0755);
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_cleanup_free_ char *extend_options = NULL;
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const char *o;
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if (p->options_fn) {
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r = p->options_fn(priority, p->type, &extend_options);
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if (r < 0)
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return r;
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if (!strprepend_with_separator(&extend_options, ",", p->options))
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return log_oom();
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o = extend_options;
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} else
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o = p->options;
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r = mount_verbose_full(priority, p->what, p->where, p->type, p->flags, o, FLAGS_SET(p->mode, MNT_FOLLOW_SYMLINK));
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if (r < 0)
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return FLAGS_SET(p->mode, MNT_FATAL) ? r : 0;
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/* Relabel again, since we now mounted something fresh here */
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if (relabel)
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(void) label_fix(p->where, 0);
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if (FLAGS_SET(p->mode, MNT_CHECK_WRITABLE))
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if (access(p->where, W_OK) < 0) {
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r = -errno;
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(void) umount2(p->where, UMOUNT_NOFOLLOW);
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(void) rmdir(p->where);
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log_full_errno(priority, r, "Mount point '%s' not writable after mounting, undoing: %m", p->where);
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return FLAGS_SET(p->mode, MNT_FATAL) ? r : 0;
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}
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return 1;
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}
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static int mount_points_setup(size_t n, bool loaded_policy) {
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int r = 0;
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assert(n <= ELEMENTSOF(mount_table));
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FOREACH_ARRAY(mp, mount_table, n)
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RET_GATHER(r, mount_one(mp, loaded_policy));
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return r;
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}
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int mount_setup_early(void) {
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/* Do a minimal mount of /proc and friends to enable the most basic stuff, such as SELinux */
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return mount_points_setup(N_EARLY_MOUNT, /* loaded_policy= */ false);
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}
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#if HAVE_SELINUX || ENABLE_SMACK
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static int relabel_cb(
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RecurseDirEvent event,
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const char *path,
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int dir_fd,
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int inode_fd,
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const struct dirent *de,
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const struct statx *sx,
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void *userdata) {
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switch (event) {
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case RECURSE_DIR_LEAVE:
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case RECURSE_DIR_SKIP_MOUNT:
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/* If we already saw this dirent when entering it or this is a dirent that on a different
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* mount, don't relabel it. */
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return RECURSE_DIR_CONTINUE;
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case RECURSE_DIR_ENTER:
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/* /run/initramfs/ + /run/nextroot/ are static data and big, no need to dynamically relabel
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* its contents at boot... */
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if (PATH_STARTSWITH_SET(path, "/run/initramfs", "/run/nextroot"))
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return RECURSE_DIR_SKIP_ENTRY;
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_fallthrough_;
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default:
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/* Otherwise, label it, even if we had trouble stat()ing it and similar. SELinux can figure this out */
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(void) label_fix(path, 0);
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return RECURSE_DIR_CONTINUE;
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}
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}
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static int relabel_tree(const char *path) {
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int r;
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r = recurse_dir_at(AT_FDCWD, path, 0, UINT_MAX, RECURSE_DIR_ENSURE_TYPE|RECURSE_DIR_SAME_MOUNT, relabel_cb, NULL);
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if (r < 0)
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log_debug_errno(r, "Failed to recursively relabel '%s': %m", path);
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return r;
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}
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static int relabel_extra(void) {
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_cleanup_strv_free_ char **files = NULL;
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int r, c = 0;
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/* Support for relabelling additional files or directories after loading the policy. For this, code in the
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* initrd simply has to drop in *.relabel files into /run/systemd/relabel-extra.d/. We'll read all such files
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* expecting one absolute path by line and will relabel each (and everyone below that in case the path refers
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* to a directory). These drop-in files are supposed to be absolutely minimal, and do not understand comments
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* and such. After the operation succeeded the files are removed, and the drop-in directory as well, if
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* possible.
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*/
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r = conf_files_list(&files, ".relabel", NULL,
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CONF_FILES_FILTER_MASKED | CONF_FILES_REGULAR,
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"/run/systemd/relabel-extra.d/");
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if (r < 0)
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return log_error_errno(r, "Failed to enumerate /run/systemd/relabel-extra.d/, ignoring: %m");
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STRV_FOREACH(file, files) {
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_cleanup_fclose_ FILE *f = NULL;
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f = fopen(*file, "re");
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if (!f) {
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log_warning_errno(errno, "Failed to open %s, ignoring: %m", *file);
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continue;
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}
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for (;;) {
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_cleanup_free_ char *line = NULL;
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r = read_line(f, LONG_LINE_MAX, &line);
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if (r < 0) {
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log_warning_errno(r, "Failed to read %s, ignoring: %m", *file);
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break;
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}
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if (r == 0) /* EOF */
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break;
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path_simplify(line);
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if (!path_is_normalized(line)) {
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log_warning("Path to relabel is not normalized, ignoring: %s", line);
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continue;
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}
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if (!path_is_absolute(line)) {
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log_warning("Path to relabel is not absolute, ignoring: %s", line);
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continue;
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}
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log_debug("Relabelling additional file/directory '%s'.", line);
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(void) label_fix(line, 0);
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(void) relabel_tree(line);
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c++;
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}
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if (unlink(*file) < 0)
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log_warning_errno(errno, "Failed to remove %s, ignoring: %m", *file);
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}
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/* Remove when we complete things. */
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if (rmdir("/run/systemd/relabel-extra.d") < 0 &&
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errno != ENOENT)
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log_warning_errno(errno, "Failed to remove /run/systemd/relabel-extra.d/ directory: %m");
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return c;
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}
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#endif
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int mount_setup(bool loaded_policy, bool leave_propagation) {
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int r;
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r = mount_points_setup(ELEMENTSOF(mount_table), loaded_policy);
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if (r < 0)
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return r;
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#if HAVE_SELINUX || ENABLE_SMACK
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/* Nodes in devtmpfs and /run need to be manually updated for
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* the appropriate labels, after mounting. The other virtual
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* API file systems like /sys and /proc do not need that, they
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* use the same label for all their files. */
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if (loaded_policy) {
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|
usec_t before_relabel, after_relabel;
|
|
int n_extra;
|
|
|
|
before_relabel = now(CLOCK_MONOTONIC);
|
|
|
|
FOREACH_STRING(i, "/dev", "/dev/shm", "/run")
|
|
(void) relabel_tree(i);
|
|
|
|
n_extra = relabel_extra();
|
|
|
|
after_relabel = now(CLOCK_MONOTONIC);
|
|
|
|
log_info("Relabeled /dev/, /dev/shm/, /run/%s in %s.",
|
|
n_extra > 0 ? ", and additional files" : "",
|
|
FORMAT_TIMESPAN(after_relabel - before_relabel, 0));
|
|
}
|
|
#endif
|
|
|
|
/* Create a few default symlinks, which are normally created
|
|
* by udevd, but some scripts might need them before we start
|
|
* udevd. */
|
|
dev_setup(NULL, UID_INVALID, GID_INVALID);
|
|
|
|
/* Mark the root directory as shared in regards to mount propagation. The kernel defaults to "private", but we
|
|
* think it makes more sense to have a default of "shared" so that nspawn and the container tools work out of
|
|
* the box. If specific setups need other settings they can reset the propagation mode to private if
|
|
* needed. Note that we set this only when we are invoked directly by the kernel. If we are invoked by a
|
|
* container manager we assume the container manager knows what it is doing (for example, because it set up
|
|
* some directories with different propagation modes). */
|
|
if (detect_container() <= 0 && !leave_propagation)
|
|
if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0)
|
|
log_warning_errno(errno, "Failed to set up the root directory for shared mount propagation: %m");
|
|
|
|
/* Create a few directories we always want around, Note that sd_booted() checks for /run/systemd/system, so
|
|
* this mkdir really needs to stay for good, otherwise software that copied sd-daemon.c into their sources will
|
|
* misdetect systemd. */
|
|
(void) mkdir_label("/run/systemd", 0755);
|
|
(void) mkdir_label("/run/systemd/system", 0755);
|
|
|
|
/* Make sure there's always a place where sandboxed environments can mount root file systems they are
|
|
* about to move into, even when unprivileged, without having to create a temporary one in /tmp/
|
|
* (which they then have to keep track of and clean) */
|
|
(void) mkdir_label("/run/systemd/mount-rootfs", 0555);
|
|
|
|
/* Make sure we have a mount point to hide in sandboxes */
|
|
(void) mkdir_label("/run/credentials", 0755);
|
|
|
|
/* Also create /run/systemd/inaccessible nodes, so that we always have something to mount
|
|
* inaccessible nodes from. If we run in a container the host might have created these for us already
|
|
* in /run/host/inaccessible/. Use those if we can, since that way we likely get access to block/char
|
|
* device nodes that are inaccessible, and if userns is used to nodes that are on mounts owned by a
|
|
* userns outside the container and thus nicely read-only and not remountable. */
|
|
if (access("/run/host/inaccessible/", F_OK) < 0) {
|
|
if (errno != ENOENT)
|
|
log_debug_errno(errno, "Failed to check if /run/host/inaccessible exists, ignoring: %m");
|
|
|
|
(void) make_inaccessible_nodes("/run/systemd", UID_INVALID, GID_INVALID);
|
|
} else
|
|
(void) symlink("../host/inaccessible", "/run/systemd/inaccessible");
|
|
|
|
return 0;
|
|
}
|