| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2015 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <sys/mount.h> |
| |
| #include "util.h" |
| #include "rm-rf.h" |
| #include "strv.h" |
| #include "path-util.h" |
| #include "mkdir.h" |
| #include "label.h" |
| #include "set.h" |
| #include "cgroup-util.h" |
| |
| #include "nspawn-mount.h" |
| |
| CustomMount* custom_mount_add(CustomMount **l, unsigned *n, CustomMountType t) { |
| CustomMount *c, *ret; |
| |
| assert(l); |
| assert(n); |
| assert(t >= 0); |
| assert(t < _CUSTOM_MOUNT_TYPE_MAX); |
| |
| c = realloc(*l, (*n + 1) * sizeof(CustomMount)); |
| if (!c) |
| return NULL; |
| |
| *l = c; |
| ret = *l + *n; |
| (*n)++; |
| |
| *ret = (CustomMount) { .type = t }; |
| |
| return ret; |
| } |
| |
| void custom_mount_free_all(CustomMount *l, unsigned n) { |
| unsigned i; |
| |
| for (i = 0; i < n; i++) { |
| CustomMount *m = l + i; |
| |
| free(m->source); |
| free(m->destination); |
| free(m->options); |
| |
| if (m->work_dir) { |
| (void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL); |
| free(m->work_dir); |
| } |
| |
| strv_free(m->lower); |
| } |
| |
| free(l); |
| } |
| |
| int custom_mount_compare(const void *a, const void *b) { |
| const CustomMount *x = a, *y = b; |
| int r; |
| |
| r = path_compare(x->destination, y->destination); |
| if (r != 0) |
| return r; |
| |
| if (x->type < y->type) |
| return -1; |
| if (x->type > y->type) |
| return 1; |
| |
| return 0; |
| } |
| |
| int bind_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_only) { |
| _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL; |
| const char *p = s; |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| |
| r = extract_many_words(&p, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| |
| if (r == 1) { |
| destination = strdup(source); |
| if (!destination) |
| return -ENOMEM; |
| } |
| |
| if (r == 2 && !isempty(p)) { |
| opts = strdup(p); |
| if (!opts) |
| return -ENOMEM; |
| } |
| |
| if (!path_is_absolute(source)) |
| return -EINVAL; |
| |
| if (!path_is_absolute(destination)) |
| return -EINVAL; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); |
| if (!m) |
| return log_oom(); |
| |
| m->source = source; |
| m->destination = destination; |
| m->read_only = read_only; |
| m->options = opts; |
| |
| source = destination = opts = NULL; |
| return 0; |
| } |
| |
| int tmpfs_mount_parse(CustomMount **l, unsigned *n, const char *s) { |
| _cleanup_free_ char *path = NULL, *opts = NULL; |
| const char *p = s; |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| assert(s); |
| |
| r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| |
| if (isempty(p)) |
| opts = strdup("mode=0755"); |
| else |
| opts = strdup(p); |
| if (!opts) |
| return -ENOMEM; |
| |
| if (!path_is_absolute(path)) |
| return -EINVAL; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS); |
| if (!m) |
| return -ENOMEM; |
| |
| m->destination = path; |
| m->options = opts; |
| |
| path = opts = NULL; |
| return 0; |
| } |
| |
| static int tmpfs_patch_options( |
| const char *options, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context, |
| char **ret) { |
| |
| char *buf = NULL; |
| |
| if (userns && uid_shift != 0) { |
| assert(uid_shift != UID_INVALID); |
| |
| if (options) |
| (void) asprintf(&buf, "%s,uid=" UID_FMT ",gid=" UID_FMT, options, uid_shift, uid_shift); |
| else |
| (void) asprintf(&buf, "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift); |
| if (!buf) |
| return -ENOMEM; |
| |
| options = buf; |
| } |
| |
| #ifdef HAVE_SELINUX |
| if (selinux_apifs_context) { |
| char *t; |
| |
| if (options) |
| t = strjoin(options, ",context=\"", selinux_apifs_context, "\"", NULL); |
| else |
| t = strjoin("context=\"", selinux_apifs_context, "\"", NULL); |
| if (!t) { |
| free(buf); |
| return -ENOMEM; |
| } |
| |
| free(buf); |
| buf = t; |
| } |
| #endif |
| |
| *ret = buf; |
| return !!buf; |
| } |
| |
| int mount_all(const char *dest, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| typedef struct MountPoint { |
| const char *what; |
| const char *where; |
| const char *type; |
| const char *options; |
| unsigned long flags; |
| bool fatal; |
| bool userns; |
| } MountPoint; |
| |
| static const MountPoint mount_table[] = { |
| { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true, true }, |
| { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true, true }, /* Bind mount first */ |
| { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, true, true }, /* Then, make it r/o */ |
| { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false }, |
| { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true, false }, |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false }, |
| { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false }, |
| { "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_STRICTATIME, true, false }, |
| #ifdef HAVE_SELINUX |
| { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false, false }, /* Bind mount first */ |
| { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, false }, /* Then, make it r/o */ |
| #endif |
| }; |
| |
| unsigned k; |
| int r; |
| |
| for (k = 0; k < ELEMENTSOF(mount_table); k++) { |
| _cleanup_free_ char *where = NULL, *options = NULL; |
| const char *o; |
| |
| if (userns != mount_table[k].userns) |
| continue; |
| |
| where = prefix_root(dest, mount_table[k].where); |
| if (!where) |
| return log_oom(); |
| |
| r = path_is_mount_point(where, AT_SYMLINK_FOLLOW); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); |
| |
| /* Skip this entry if it is not a remount. */ |
| if (mount_table[k].what && r > 0) |
| continue; |
| |
| r = mkdir_p(where, 0755); |
| if (r < 0) { |
| if (mount_table[k].fatal) |
| return log_error_errno(r, "Failed to create directory %s: %m", where); |
| |
| log_warning_errno(r, "Failed to create directory %s: %m", where); |
| continue; |
| } |
| |
| o = mount_table[k].options; |
| if (streq_ptr(mount_table[k].type, "tmpfs")) { |
| r = tmpfs_patch_options(o, userns, uid_shift, uid_range, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| o = options; |
| } |
| |
| if (mount(mount_table[k].what, |
| where, |
| mount_table[k].type, |
| mount_table[k].flags, |
| o) < 0) { |
| |
| if (mount_table[k].fatal) |
| return log_error_errno(errno, "mount(%s) failed: %m", where); |
| |
| log_warning_errno(errno, "mount(%s) failed, ignoring: %m", where); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts) { |
| const char *p = options; |
| unsigned long flags = *mount_flags; |
| char *opts = NULL; |
| |
| assert(options); |
| |
| for (;;) { |
| _cleanup_free_ char *word = NULL; |
| int r = extract_first_word(&p, &word, ",", 0); |
| if (r < 0) |
| return log_error_errno(r, "Failed to extract mount option: %m"); |
| if (r == 0) |
| break; |
| |
| if (streq(word, "rbind")) |
| flags |= MS_REC; |
| else if (streq(word, "norbind")) |
| flags &= ~MS_REC; |
| else { |
| log_error("Invalid bind mount option: %s", word); |
| return -EINVAL; |
| } |
| } |
| |
| *mount_flags = flags; |
| /* in the future mount_opts will hold string options for mount(2) */ |
| *mount_opts = opts; |
| |
| return 0; |
| } |
| |
| static int mount_bind(const char *dest, CustomMount *m) { |
| struct stat source_st, dest_st; |
| const char *where; |
| unsigned long mount_flags = MS_BIND | MS_REC; |
| _cleanup_free_ char *mount_opts = NULL; |
| int r; |
| |
| assert(m); |
| |
| if (m->options) { |
| r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts); |
| if (r < 0) |
| return r; |
| } |
| |
| if (stat(m->source, &source_st) < 0) |
| return log_error_errno(errno, "Failed to stat %s: %m", m->source); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| if (stat(where, &dest_st) >= 0) { |
| if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) { |
| log_error("Cannot bind mount directory %s on file %s.", m->source, where); |
| return -EINVAL; |
| } |
| |
| if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) { |
| log_error("Cannot bind mount file %s on directory %s.", m->source, where); |
| return -EINVAL; |
| } |
| |
| } else if (errno == ENOENT) { |
| r = mkdir_parents_label(where, 0755); |
| if (r < 0) |
| return log_error_errno(r, "Failed to make parents of %s: %m", where); |
| } else { |
| log_error_errno(errno, "Failed to stat %s: %m", where); |
| return -errno; |
| } |
| |
| /* Create the mount point. Any non-directory file can be |
| * mounted on any non-directory file (regular, fifo, socket, |
| * char, block). |
| */ |
| if (S_ISDIR(source_st.st_mode)) |
| r = mkdir_label(where, 0755); |
| else |
| r = touch(where); |
| if (r < 0 && r != -EEXIST) |
| return log_error_errno(r, "Failed to create mount point %s: %m", where); |
| |
| if (mount(m->source, where, NULL, mount_flags, mount_opts) < 0) |
| return log_error_errno(errno, "mount(%s) failed: %m", where); |
| |
| if (m->read_only) { |
| r = bind_remount_recursive(where, true); |
| if (r < 0) |
| return log_error_errno(r, "Read-only bind mount failed: %m"); |
| } |
| |
| return 0; |
| } |
| |
| static int mount_tmpfs( |
| const char *dest, |
| CustomMount *m, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| const char *where, *options; |
| _cleanup_free_ char *buf = NULL; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| r = mkdir_p_label(where, 0755); |
| if (r < 0 && r != -EEXIST) |
| return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); |
| |
| r = tmpfs_patch_options(m->options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| options = r > 0 ? buf : m->options; |
| |
| if (mount("tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options) < 0) |
| return log_error_errno(errno, "tmpfs mount to %s failed: %m", where); |
| |
| return 0; |
| } |
| |
| static char *joined_and_escaped_lower_dirs(char * const *lower) { |
| _cleanup_strv_free_ char **sv = NULL; |
| |
| sv = strv_copy(lower); |
| if (!sv) |
| return NULL; |
| |
| strv_reverse(sv); |
| |
| if (!strv_shell_escape(sv, ",:")) |
| return NULL; |
| |
| return strv_join(sv, ":"); |
| } |
| |
| static int mount_overlay(const char *dest, CustomMount *m) { |
| _cleanup_free_ char *lower = NULL; |
| const char *where, *options; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| r = mkdir_label(where, 0755); |
| if (r < 0 && r != -EEXIST) |
| return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where); |
| |
| (void) mkdir_p_label(m->source, 0755); |
| |
| lower = joined_and_escaped_lower_dirs(m->lower); |
| if (!lower) |
| return log_oom(); |
| |
| if (m->read_only) { |
| _cleanup_free_ char *escaped_source = NULL; |
| |
| escaped_source = shell_escape(m->source, ",:"); |
| if (!escaped_source) |
| return log_oom(); |
| |
| options = strjoina("lowerdir=", escaped_source, ":", lower); |
| } else { |
| _cleanup_free_ char *escaped_source = NULL, *escaped_work_dir = NULL; |
| |
| assert(m->work_dir); |
| (void) mkdir_label(m->work_dir, 0700); |
| |
| escaped_source = shell_escape(m->source, ",:"); |
| if (!escaped_source) |
| return log_oom(); |
| escaped_work_dir = shell_escape(m->work_dir, ",:"); |
| if (!escaped_work_dir) |
| return log_oom(); |
| |
| options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir); |
| } |
| |
| if (mount("overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options) < 0) |
| return log_error_errno(errno, "overlay mount to %s failed: %m", where); |
| |
| return 0; |
| } |
| |
| int mount_custom( |
| const char *dest, |
| CustomMount *mounts, unsigned n, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| unsigned i; |
| int r; |
| |
| assert(dest); |
| |
| for (i = 0; i < n; i++) { |
| CustomMount *m = mounts + i; |
| |
| switch (m->type) { |
| |
| case CUSTOM_MOUNT_BIND: |
| r = mount_bind(dest, m); |
| break; |
| |
| case CUSTOM_MOUNT_TMPFS: |
| r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context); |
| break; |
| |
| case CUSTOM_MOUNT_OVERLAY: |
| r = mount_overlay(dest, m); |
| break; |
| |
| default: |
| assert_not_reached("Unknown custom mount type"); |
| } |
| |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) { |
| char *to; |
| int r; |
| |
| to = strjoina(dest, "/sys/fs/cgroup/", hierarchy); |
| |
| r = path_is_mount_point(to, 0); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to determine if %s is mounted already: %m", to); |
| if (r > 0) |
| return 0; |
| |
| mkdir_p(to, 0755); |
| |
| /* The superblock mount options of the mount point need to be |
| * identical to the hosts', and hence writable... */ |
| if (mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, controller) < 0) |
| return log_error_errno(errno, "Failed to mount to %s: %m", to); |
| |
| /* ... hence let's only make the bind mount read-only, not the |
| * superblock. */ |
| if (read_only) { |
| if (mount(NULL, to, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0) |
| return log_error_errno(errno, "Failed to remount %s read-only: %m", to); |
| } |
| return 1; |
| } |
| |
| static int mount_legacy_cgroups( |
| const char *dest, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| _cleanup_set_free_free_ Set *controllers = NULL; |
| const char *cgroup_root; |
| int r; |
| |
| cgroup_root = prefix_roota(dest, "/sys/fs/cgroup"); |
| |
| /* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */ |
| r = path_is_mount_point(cgroup_root, AT_SYMLINK_FOLLOW); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m"); |
| if (r == 0) { |
| _cleanup_free_ char *options = NULL; |
| |
| r = tmpfs_patch_options("mode=755", userns, uid_shift, uid_range, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| |
| if (mount("tmpfs", cgroup_root, "tmpfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options) < 0) |
| return log_error_errno(errno, "Failed to mount /sys/fs/cgroup: %m"); |
| } |
| |
| if (cg_unified() > 0) |
| goto skip_controllers; |
| |
| controllers = set_new(&string_hash_ops); |
| if (!controllers) |
| return log_oom(); |
| |
| r = cg_kernel_controllers(controllers); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine cgroup controllers: %m"); |
| |
| for (;;) { |
| _cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL; |
| |
| controller = set_steal_first(controllers); |
| if (!controller) |
| break; |
| |
| origin = prefix_root("/sys/fs/cgroup/", controller); |
| if (!origin) |
| return log_oom(); |
| |
| r = readlink_malloc(origin, &combined); |
| if (r == -EINVAL) { |
| /* Not a symbolic link, but directly a single cgroup hierarchy */ |
| |
| r = mount_legacy_cgroup_hierarchy(dest, controller, controller, true); |
| if (r < 0) |
| return r; |
| |
| } else if (r < 0) |
| return log_error_errno(r, "Failed to read link %s: %m", origin); |
| else { |
| _cleanup_free_ char *target = NULL; |
| |
| target = prefix_root(dest, origin); |
| if (!target) |
| return log_oom(); |
| |
| /* A symbolic link, a combination of controllers in one hierarchy */ |
| |
| if (!filename_is_valid(combined)) { |
| log_warning("Ignoring invalid combined hierarchy %s.", combined); |
| continue; |
| } |
| |
| r = mount_legacy_cgroup_hierarchy(dest, combined, combined, true); |
| if (r < 0) |
| return r; |
| |
| r = symlink_idempotent(combined, target); |
| if (r == -EINVAL) { |
| log_error("Invalid existing symlink for combined hierarchy"); |
| return r; |
| } |
| if (r < 0) |
| return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); |
| } |
| } |
| |
| skip_controllers: |
| r = mount_legacy_cgroup_hierarchy(dest, "none,name=systemd,xattr", "systemd", false); |
| if (r < 0) |
| return r; |
| |
| if (mount(NULL, cgroup_root, NULL, MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755") < 0) |
| return log_error_errno(errno, "Failed to remount %s read-only: %m", cgroup_root); |
| |
| return 0; |
| } |
| |
| static int mount_unified_cgroups(const char *dest) { |
| const char *p; |
| int r; |
| |
| assert(dest); |
| |
| p = strjoina(dest, "/sys/fs/cgroup"); |
| |
| r = path_is_mount_point(p, AT_SYMLINK_FOLLOW); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine if %s is mounted already: %m", p); |
| if (r > 0) { |
| p = strjoina(dest, "/sys/fs/cgroup/cgroup.procs"); |
| if (access(p, F_OK) >= 0) |
| return 0; |
| if (errno != ENOENT) |
| return log_error_errno(errno, "Failed to determine if mount point %s contains the unified cgroup hierarchy: %m", p); |
| |
| log_error("%s is already mounted but not a unified cgroup hierarchy. Refusing.", p); |
| return -EINVAL; |
| } |
| |
| if (mount("cgroup", p, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior") < 0) |
| return log_error_errno(errno, "Failed to mount unified cgroup hierarchy to %s: %m", p); |
| |
| return 0; |
| } |
| |
| int mount_cgroups( |
| const char *dest, |
| bool unified_requested, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| if (unified_requested) |
| return mount_unified_cgroups(dest); |
| else |
| return mount_legacy_cgroups(dest, userns, uid_shift, uid_range, selinux_apifs_context); |
| } |
| |
| int mount_systemd_cgroup_writable( |
| const char *dest, |
| bool unified_requested) { |
| |
| _cleanup_free_ char *own_cgroup_path = NULL; |
| const char *systemd_root, *systemd_own; |
| int r; |
| |
| assert(dest); |
| |
| r = cg_pid_get_path(NULL, 0, &own_cgroup_path); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine our own cgroup path: %m"); |
| |
| /* If we are living in the top-level, then there's nothing to do... */ |
| if (path_equal(own_cgroup_path, "/")) |
| return 0; |
| |
| if (unified_requested) { |
| systemd_own = strjoina(dest, "/sys/fs/cgroup", own_cgroup_path); |
| systemd_root = prefix_roota(dest, "/sys/fs/cgroup"); |
| } else { |
| systemd_own = strjoina(dest, "/sys/fs/cgroup/systemd", own_cgroup_path); |
| systemd_root = prefix_roota(dest, "/sys/fs/cgroup/systemd"); |
| } |
| |
| /* Make our own cgroup a (writable) bind mount */ |
| if (mount(systemd_own, systemd_own, NULL, MS_BIND, NULL) < 0) |
| return log_error_errno(errno, "Failed to turn %s into a bind mount: %m", own_cgroup_path); |
| |
| /* And then remount the systemd cgroup root read-only */ |
| if (mount(NULL, systemd_root, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0) |
| return log_error_errno(errno, "Failed to mount cgroup root read-only: %m"); |
| |
| return 0; |
| } |
| |
| int setup_volatile_state( |
| const char *directory, |
| VolatileMode mode, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| _cleanup_free_ char *buf = NULL; |
| const char *p, *options; |
| int r; |
| |
| assert(directory); |
| |
| if (mode != VOLATILE_STATE) |
| return 0; |
| |
| /* --volatile=state means we simply overmount /var |
| with a tmpfs, and the rest read-only. */ |
| |
| r = bind_remount_recursive(directory, true); |
| if (r < 0) |
| return log_error_errno(r, "Failed to remount %s read-only: %m", directory); |
| |
| p = prefix_roota(directory, "/var"); |
| r = mkdir(p, 0755); |
| if (r < 0 && errno != EEXIST) |
| return log_error_errno(errno, "Failed to create %s: %m", directory); |
| |
| options = "mode=755"; |
| r = tmpfs_patch_options(options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| options = buf; |
| |
| if (mount("tmpfs", p, "tmpfs", MS_STRICTATIME, options) < 0) |
| return log_error_errno(errno, "Failed to mount tmpfs to /var: %m"); |
| |
| return 0; |
| } |
| |
| int setup_volatile( |
| const char *directory, |
| VolatileMode mode, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| bool tmpfs_mounted = false, bind_mounted = false; |
| char template[] = "/tmp/nspawn-volatile-XXXXXX"; |
| _cleanup_free_ char *buf = NULL; |
| const char *f, *t, *options; |
| int r; |
| |
| assert(directory); |
| |
| if (mode != VOLATILE_YES) |
| return 0; |
| |
| /* --volatile=yes means we mount a tmpfs to the root dir, and |
| the original /usr to use inside it, and that read-only. */ |
| |
| if (!mkdtemp(template)) |
| return log_error_errno(errno, "Failed to create temporary directory: %m"); |
| |
| options = "mode=755"; |
| r = tmpfs_patch_options(options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| options = buf; |
| |
| if (mount("tmpfs", template, "tmpfs", MS_STRICTATIME, options) < 0) { |
| r = log_error_errno(errno, "Failed to mount tmpfs for root directory: %m"); |
| goto fail; |
| } |
| |
| tmpfs_mounted = true; |
| |
| f = prefix_roota(directory, "/usr"); |
| t = prefix_roota(template, "/usr"); |
| |
| r = mkdir(t, 0755); |
| if (r < 0 && errno != EEXIST) { |
| r = log_error_errno(errno, "Failed to create %s: %m", t); |
| goto fail; |
| } |
| |
| if (mount(f, t, NULL, MS_BIND|MS_REC, NULL) < 0) { |
| r = log_error_errno(errno, "Failed to create /usr bind mount: %m"); |
| goto fail; |
| } |
| |
| bind_mounted = true; |
| |
| r = bind_remount_recursive(t, true); |
| if (r < 0) { |
| log_error_errno(r, "Failed to remount %s read-only: %m", t); |
| goto fail; |
| } |
| |
| if (mount(template, directory, NULL, MS_MOVE, NULL) < 0) { |
| r = log_error_errno(errno, "Failed to move root mount: %m"); |
| goto fail; |
| } |
| |
| (void) rmdir(template); |
| |
| return 0; |
| |
| fail: |
| if (bind_mounted) |
| (void) umount(t); |
| |
| if (tmpfs_mounted) |
| (void) umount(template); |
| (void) rmdir(template); |
| return r; |
| } |
| |
| VolatileMode volatile_mode_from_string(const char *s) { |
| int b; |
| |
| if (isempty(s)) |
| return _VOLATILE_MODE_INVALID; |
| |
| b = parse_boolean(s); |
| if (b > 0) |
| return VOLATILE_YES; |
| if (b == 0) |
| return VOLATILE_NO; |
| |
| if (streq(s, "state")) |
| return VOLATILE_STATE; |
| |
| return _VOLATILE_MODE_INVALID; |
| } |