diff options
Diffstat (limited to 'src/nspawn/nspawn-mount.c')
| -rw-r--r-- | src/nspawn/nspawn-mount.c | 1162 |
1 files changed, 0 insertions, 1162 deletions
diff --git a/src/nspawn/nspawn-mount.c b/src/nspawn/nspawn-mount.c deleted file mode 100644 index 2dabe2ae5b..0000000000 --- a/src/nspawn/nspawn-mount.c +++ /dev/null @@ -1,1162 +0,0 @@ -/*** - 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 <linux/magic.h> - -#include "alloc-util.h" -#include "escape.h" -#include "fd-util.h" -#include "fileio.h" -#include "fs-util.h" -#include "label.h" -#include "mkdir.h" -#include "mount-util.h" -#include "nspawn-mount.h" -#include "parse-util.h" -#include "path-util.h" -#include "rm-rf.h" -#include "set.h" -#include "stat-util.h" -#include "string-util.h" -#include "strv.h" -#include "user-util.h" -#include "util.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, - bool patch_ids, - const char *selinux_apifs_context, - char **ret) { - - char *buf = NULL; - - if ((userns && uid_shift != 0) || patch_ids) { - 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 - - if (!buf && options) { - buf = strdup(options); - if (!buf) - return -ENOMEM; - } - *ret = buf; - - return !!buf; -} - -int mount_sysfs(const char *dest) { - const char *full, *top, *x; - int r; - - top = prefix_roota(dest, "/sys"); - r = path_check_fstype(top, SYSFS_MAGIC); - if (r < 0) - return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top); - /* /sys might already be mounted as sysfs by the outer child in the - * !netns case. In this case, it's all good. Don't touch it because we - * don't have the right to do so, see https://github.com/systemd/systemd/issues/1555. - */ - if (r > 0) - return 0; - - full = prefix_roota(top, "/full"); - - (void) mkdir(full, 0755); - - r = mount_verbose(LOG_ERR, "sysfs", full, "sysfs", - MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL); - if (r < 0) - return r; - - FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { - _cleanup_free_ char *from = NULL, *to = NULL; - - from = prefix_root(full, x); - if (!from) - return log_oom(); - - to = prefix_root(top, x); - if (!to) - return log_oom(); - - (void) mkdir(to, 0755); - - r = mount_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL); - if (r < 0) - return r; - - r = mount_verbose(LOG_ERR, NULL, to, NULL, - MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL); - if (r < 0) - return r; - } - - r = umount_verbose(full); - if (r < 0) - return r; - - if (rmdir(full) < 0) - return log_error_errno(errno, "Failed to remove %s: %m", full); - - x = prefix_roota(top, "/fs/kdbus"); - (void) mkdir_p(x, 0755); - - /* Create mountpoint for cgroups. Otherwise we are not allowed since we - * remount /sys read-only. - */ - if (cg_ns_supported()) { - x = prefix_roota(top, "/fs/cgroup"); - (void) mkdir_p(x, 0755); - } - - return mount_verbose(LOG_ERR, NULL, top, NULL, - MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL); -} - -static int mkdir_userns(const char *path, mode_t mode, bool in_userns, uid_t uid_shift) { - int r; - - assert(path); - - r = mkdir(path, mode); - if (r < 0 && errno != EEXIST) - return -errno; - - if (!in_userns) { - r = lchown(path, uid_shift, uid_shift); - if (r < 0) - return -errno; - } - - return 0; -} - -static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, bool in_userns, uid_t uid_shift) { - const char *p, *e; - int r; - - assert(path); - - if (prefix && !path_startswith(path, prefix)) - return -ENOTDIR; - - /* create every parent directory in the path, except the last component */ - p = path + strspn(path, "/"); - for (;;) { - char t[strlen(path) + 1]; - - e = p + strcspn(p, "/"); - p = e + strspn(e, "/"); - - /* Is this the last component? If so, then we're done */ - if (*p == 0) - break; - - memcpy(t, path, e - path); - t[e-path] = 0; - - if (prefix && path_startswith(prefix, t)) - continue; - - r = mkdir_userns(t, mode, in_userns, uid_shift); - if (r < 0) - return r; - } - - return mkdir_userns(path, mode, in_userns, uid_shift); -} - -int mount_all(const char *dest, - bool use_userns, bool in_userns, - bool use_netns, - 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 in_userns; - bool use_netns; - } MountPoint; - - static const MountPoint mount_table[] = { - { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true, true, false }, - { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true, true, false }, /* Bind mount first ...*/ - { "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, true, true, true }, /* (except for this) */ - { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, true, true, false }, /* ... then, make it r/o */ - { "/proc/sysrq-trigger", "/proc/sysrq-trigger", NULL, NULL, MS_BIND, false, true, false }, /* Bind mount first ...*/ - { NULL, "/proc/sysrq-trigger", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, true, false }, /* ... then, make it r/o */ - { "tmpfs", "/sys", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, true }, - { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, false }, - { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true, false, false }, - { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, - { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, - { "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_STRICTATIME, true, false, false }, -#ifdef HAVE_SELINUX - { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false, 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, 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 (in_userns != mount_table[k].in_userns) - continue; - - if (!use_netns && mount_table[k].use_netns) - 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_userns_p(dest, where, 0755, in_userns, uid_shift); - if (r < 0 && r != -EEXIST) { - if (mount_table[k].fatal) - return log_error_errno(r, "Failed to create directory %s: %m", where); - - log_debug_errno(r, "Failed to create directory %s: %m", where); - continue; - } - - o = mount_table[k].options; - if (streq_ptr(mount_table[k].type, "tmpfs")) { - if (in_userns) - r = tmpfs_patch_options(o, use_userns, 0, uid_range, true, selinux_apifs_context, &options); - else - r = tmpfs_patch_options(o, use_userns, uid_shift, uid_range, false, selinux_apifs_context, &options); - if (r < 0) - return log_oom(); - if (r > 0) - o = options; - } - - r = mount_verbose(mount_table[k].fatal ? LOG_ERR : LOG_WARNING, - mount_table[k].what, - where, - mount_table[k].type, - mount_table[k].flags, - o); - if (r < 0 && mount_table[k].fatal) - return r; - } - - 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); - - /* 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) - return log_error_errno(r, "Failed to create mount point %s: %m", where); - - } else - return log_error_errno(errno, "Failed to stat %s: %m", where); - - r = mount_verbose(LOG_ERR, m->source, where, NULL, mount_flags, mount_opts); - if (r < 0) - return r; - - if (m->read_only) { - r = bind_remount_recursive(where, true, NULL); - 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, false, selinux_apifs_context, &buf); - if (r < 0) - return log_oom(); - options = r > 0 ? buf : m->options; - - return mount_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options); -} - -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); - } - - return mount_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options); -} - -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; -} - -/* Retrieve existing subsystems. This function is called in a new cgroup - * namespace. - */ -static int get_controllers(Set *subsystems) { - _cleanup_fclose_ FILE *f = NULL; - char line[LINE_MAX]; - - assert(subsystems); - - f = fopen("/proc/self/cgroup", "re"); - if (!f) - return errno == ENOENT ? -ESRCH : -errno; - - FOREACH_LINE(line, f, return -errno) { - int r; - char *e, *l, *p; - - l = strchr(line, ':'); - if (!l) - continue; - - l++; - e = strchr(l, ':'); - if (!e) - continue; - - *e = 0; - - if (STR_IN_SET(l, "", "name=systemd")) - continue; - - p = strdup(l); - if (!p) - return -ENOMEM; - - r = set_consume(subsystems, p); - if (r < 0) - return r; - } - - return 0; -} - -static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, - CGroupUnified unified_requested, bool read_only) { - const char *to, *fstype, *opts; - int r; - - to = strjoina(strempty(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 (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { - if (unified_requested >= CGROUP_UNIFIED_SYSTEMD) { - fstype = "cgroup2"; - opts = NULL; - } else { - fstype = "cgroup"; - opts = "none,name=systemd,xattr"; - } - } else { - fstype = "cgroup"; - opts = controller; - } - - r = mount_verbose(LOG_ERR, "cgroup", to, fstype, MS_NOSUID|MS_NOEXEC|MS_NODEV, opts); - if (r < 0) - return r; - - /* ... hence let's only make the bind mount read-only, not the superblock. */ - if (read_only) { - r = mount_verbose(LOG_ERR, NULL, to, NULL, - MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL); - if (r < 0) - return r; - } - - return 1; -} - -/* Mount a legacy cgroup hierarchy when cgroup namespaces are supported. */ -static int mount_legacy_cgns_supported( - CGroupUnified unified_requested, 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 = "/sys/fs/cgroup", *c; - int r; - - (void) mkdir_p(cgroup_root, 0755); - - /* 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; - - /* When cgroup namespaces are enabled and user namespaces are - * used then the mount of the cgroupfs is done *inside* the new - * user namespace. We're root in the new user namespace and the - * kernel will happily translate our uid/gid to the correct - * uid/gid as seen from e.g. /proc/1/mountinfo. So we simply - * pass uid 0 and not uid_shift to tmpfs_patch_options(). - */ - r = tmpfs_patch_options("mode=755", userns, 0, uid_range, true, selinux_apifs_context, &options); - if (r < 0) - return log_oom(); - - r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs", - MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options); - if (r < 0) - return r; - } - - if (cg_all_unified() > 0) - goto skip_controllers; - - controllers = set_new(&string_hash_ops); - if (!controllers) - return log_oom(); - - r = get_controllers(controllers); - if (r < 0) - return log_error_errno(r, "Failed to determine cgroup controllers: %m"); - - for (;;) { - _cleanup_free_ const char *controller = NULL; - - controller = set_steal_first(controllers); - if (!controller) - break; - - r = mount_legacy_cgroup_hierarchy("", controller, controller, unified_requested, !userns); - if (r < 0) - return r; - - /* When multiple hierarchies are co-mounted, make their - * constituting individual hierarchies a symlink to the - * co-mount. - */ - c = controller; - for (;;) { - _cleanup_free_ char *target = NULL, *tok = NULL; - - r = extract_first_word(&c, &tok, ",", 0); - if (r < 0) - return log_error_errno(r, "Failed to extract co-mounted cgroup controller: %m"); - if (r == 0) - break; - - target = prefix_root("/sys/fs/cgroup", tok); - if (!target) - return log_oom(); - - if (streq(controller, tok)) - break; - - r = symlink_idempotent(controller, target); - if (r == -EINVAL) - return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m"); - if (r < 0) - return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); - } - } - -skip_controllers: - r = mount_legacy_cgroup_hierarchy("", SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false); - if (r < 0) - return r; - - if (!userns) - return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL, - MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); - - return 0; -} - -/* Mount legacy cgroup hierarchy when cgroup namespaces are unsupported. */ -static int mount_legacy_cgns_unsupported( - const char *dest, - CGroupUnified unified_requested, 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"); - - (void) mkdir_p(cgroup_root, 0755); - - /* 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, false, selinux_apifs_context, &options); - if (r < 0) - return log_oom(); - - r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs", - MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options); - if (r < 0) - return r; - } - - if (cg_all_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, unified_requested, 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, unified_requested, true); - if (r < 0) - return r; - - r = symlink_idempotent(combined, target); - if (r == -EINVAL) - return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m"); - if (r < 0) - return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); - } - } - -skip_controllers: - r = mount_legacy_cgroup_hierarchy(dest, SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false); - if (r < 0) - return r; - - return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL, - MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); -} - -static int mount_unified_cgroups(const char *dest) { - const char *p; - int r; - - assert(dest); - - p = prefix_roota(dest, "/sys/fs/cgroup"); - - (void) mkdir_p(p, 0755); - - 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 = prefix_roota(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; - } - - return mount_verbose(LOG_ERR, "cgroup", p, "cgroup2", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL); -} - -int mount_cgroups( - const char *dest, - CGroupUnified unified_requested, - bool userns, uid_t uid_shift, uid_t uid_range, - const char *selinux_apifs_context, - bool use_cgns) { - - if (unified_requested >= CGROUP_UNIFIED_ALL) - return mount_unified_cgroups(dest); - else if (use_cgns) - return mount_legacy_cgns_supported(unified_requested, userns, uid_shift, uid_range, selinux_apifs_context); - - return mount_legacy_cgns_unsupported(dest, unified_requested, userns, uid_shift, uid_range, selinux_apifs_context); -} - -int mount_systemd_cgroup_writable( - const char *dest, - CGroupUnified 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 >= CGROUP_UNIFIED_ALL) { - 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 */ - r = mount_verbose(LOG_ERR, systemd_own, systemd_own, NULL, MS_BIND, NULL); - if (r < 0) - return r; - - /* And then remount the systemd cgroup root read-only */ - return mount_verbose(LOG_ERR, NULL, systemd_root, NULL, - MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL); -} - -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, NULL); - 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, false, selinux_apifs_context, &buf); - if (r < 0) - return log_oom(); - if (r > 0) - options = buf; - - return mount_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options); -} - -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, false, selinux_apifs_context, &buf); - if (r < 0) - return log_oom(); - if (r > 0) - options = buf; - - r = mount_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); - if (r < 0) - 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; - } - - r = mount_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL); - if (r < 0) - goto fail; - - bind_mounted = true; - - r = bind_remount_recursive(t, true, NULL); - if (r < 0) { - log_error_errno(r, "Failed to remount %s read-only: %m", t); - goto fail; - } - - r = mount_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL); - if (r < 0) - goto fail; - - (void) rmdir(template); - - return 0; - -fail: - if (bind_mounted) - (void) umount_verbose(t); - - if (tmpfs_mounted) - (void) umount_verbose(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; -} |