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Diffstat (limited to 'src/nspawn/nspawn.c')
-rw-r--r--src/nspawn/nspawn.c233
1 files changed, 220 insertions, 13 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 8039847a72..a56960506c 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -204,6 +204,7 @@ static char **arg_property = NULL;
static uid_t arg_uid_shift = UID_INVALID, arg_uid_range = 0x10000U;
static bool arg_userns = false;
static int arg_kill_signal = 0;
+static bool arg_unified_cgroup_hierarchy = false;
static void help(void) {
printf("%s [OPTIONS...] [PATH] [ARGUMENTS...]\n\n"
@@ -385,6 +386,30 @@ static int set_sanitized_path(char **b, const char *path) {
return 0;
}
+static int detect_unified_cgroup_hierarchy(void) {
+ const char *e;
+ int r;
+
+ /* Allow the user to control whether the unified hierarchy is used */
+ e = getenv("UNIFIED_CGROUP_HIERARCHY");
+ if (e) {
+ r = parse_boolean(e);
+ if (r < 0)
+ return log_error_errno(r, "Failed to parse $UNIFIED_CGROUP_HIERARCHY.");
+
+ arg_unified_cgroup_hierarchy = r;
+ return 0;
+ }
+
+ /* Otherwise inherit the default from the host system */
+ r = cg_unified();
+ if (r < 0)
+ return log_error_errno(r, "Failed to determine whether the unified cgroups hierarchy is used: %m");
+
+ arg_unified_cgroup_hierarchy = r;
+ return 0;
+}
+
static int parse_argv(int argc, char *argv[]) {
enum {
@@ -1037,6 +1062,10 @@ static int parse_argv(int argc, char *argv[]) {
if (arg_boot && arg_kill_signal <= 0)
arg_kill_signal = SIGRTMIN+3;
+ r = detect_unified_cgroup_hierarchy();
+ if (r < 0)
+ return r;
+
return 1;
}
@@ -1095,7 +1124,6 @@ static int mount_all(const char *dest, bool userns) {
{ "/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", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, 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 },
@@ -1381,7 +1409,7 @@ static int mount_custom(const char *dest) {
return 0;
}
-static int mount_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) {
+static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) {
char *to;
int r;
@@ -1409,11 +1437,31 @@ static int mount_cgroup_hierarchy(const char *dest, const char *controller, cons
return 1;
}
-static int mount_cgroup(const char *dest) {
+static int mount_legacy_cgroups(const char *dest) {
_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", &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();
@@ -1437,7 +1485,7 @@ static int mount_cgroup(const char *dest) {
if (r == -EINVAL) {
/* Not a symbolic link, but directly a single cgroup hierarchy */
- r = mount_cgroup_hierarchy(dest, controller, controller, true);
+ r = mount_legacy_cgroup_hierarchy(dest, controller, controller, true);
if (r < 0)
return r;
@@ -1457,7 +1505,7 @@ static int mount_cgroup(const char *dest) {
continue;
}
- r = mount_cgroup_hierarchy(dest, combined, combined, true);
+ r = mount_legacy_cgroup_hierarchy(dest, combined, combined, true);
if (r < 0)
return r;
@@ -1471,17 +1519,52 @@ static int mount_cgroup(const char *dest) {
}
}
- r = mount_cgroup_hierarchy(dest, "name=systemd,xattr", "systemd", false);
+skip_controllers:
+ r = mount_legacy_cgroup_hierarchy(dest, "none,name=systemd,xattr", "systemd", false);
if (r < 0)
return r;
- cgroup_root = prefix_roota(dest, "/sys/fs/cgroup");
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;
+}
+
+static int mount_cgroups(const char *dest) {
+ if (arg_unified_cgroup_hierarchy)
+ return mount_unified_cgroups(dest);
+ else
+ return mount_legacy_cgroups(dest);
+}
+
static int mount_systemd_cgroup_writable(const char *dest) {
_cleanup_free_ char *own_cgroup_path = NULL;
const char *systemd_root, *systemd_own;
@@ -1493,13 +1576,23 @@ static int mount_systemd_cgroup_writable(const char *dest) {
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 (arg_unified_cgroup_hierarchy) {
+ 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 */
- systemd_own = strjoina(dest, "/sys/fs/cgroup/systemd", own_cgroup_path);
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 */
- systemd_root = prefix_roota(dest, "/sys/fs/cgroup/systemd");
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");
@@ -4187,6 +4280,8 @@ static int inner_child(
assert(directory);
assert(kmsg_socket >= 0);
+ cg_unified_flush();
+
if (arg_userns) {
/* Tell the parent, that it now can write the UID map. */
(void) barrier_place(barrier); /* #1 */
@@ -4368,6 +4463,8 @@ static int outer_child(
assert(pid_socket >= 0);
assert(kmsg_socket >= 0);
+ cg_unified_flush();
+
if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0)
return log_error_errno(errno, "PR_SET_PDEATHSIG failed: %m");
@@ -4484,7 +4581,7 @@ static int outer_child(
if (r < 0)
return r;
- r = mount_cgroup(directory);
+ r = mount_cgroups(directory);
if (r < 0)
return r;
@@ -4499,7 +4596,6 @@ static int outer_child(
NULL);
if (pid < 0)
return log_error_errno(errno, "Failed to fork inner child: %m");
-
if (pid == 0) {
pid_socket = safe_close(pid_socket);
uid_shift_socket = safe_close(uid_shift_socket);
@@ -4567,9 +4663,112 @@ static int chown_cgroup(pid_t pid) {
if (fd < 0)
return log_error_errno(errno, "Failed to open %s: %m", fs);
- FOREACH_STRING(fn, ".", "tasks", "notify_on_release", "cgroup.procs", "cgroup.clone_children")
+ FOREACH_STRING(fn,
+ ".",
+ "tasks",
+ "notify_on_release",
+ "cgroup.procs",
+ "cgroup.clone_children",
+ "cgroup.controllers",
+ "cgroup.subtree_control",
+ "cgroup.populated")
if (fchownat(fd, fn, arg_uid_shift, arg_uid_shift, 0) < 0)
- log_warning_errno(errno, "Failed to chown() cgroup file %s, ignoring: %m", fn);
+ log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno,
+ "Failed to chown() cgroup file %s, ignoring: %m", fn);
+
+ return 0;
+}
+
+static int sync_cgroup(pid_t pid) {
+ _cleanup_free_ char *cgroup = NULL;
+ char tree[] = "/tmp/unifiedXXXXXX", pid_string[DECIMAL_STR_MAX(pid) + 1];
+ bool undo_mount = false;
+ const char *fn;
+ int unified, r;
+
+ unified = cg_unified();
+ if (unified < 0)
+ return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
+
+ if ((unified > 0) == arg_unified_cgroup_hierarchy)
+ return 0;
+
+ /* When the host uses the legacy cgroup setup, but the
+ * container shall use the unified hierarchy, let's make sure
+ * we copy the path from the name=systemd hierarchy into the
+ * unified hierarchy. Similar for the reverse situation. */
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cgroup);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get control group of " PID_FMT ": %m", pid);
+
+ /* In order to access the unified hierarchy we need to mount it */
+ if (!mkdtemp(tree))
+ return log_error_errno(errno, "Failed to generate temporary mount point for unified hierarchy: %m");
+
+ if (unified)
+ r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr");
+ else
+ r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior");
+ if (r < 0) {
+ r = log_error_errno(errno, "Failed to mount unified hierarchy: %m");
+ goto finish;
+ }
+
+ undo_mount = true;
+
+ fn = strjoina(tree, cgroup, "/cgroup.procs");
+ (void) mkdir_parents(fn, 0755);
+
+ sprintf(pid_string, PID_FMT, pid);
+ r = write_string_file(fn, pid_string, 0);
+ if (r < 0)
+ log_error_errno(r, "Failed to move process: %m");
+
+finish:
+ if (undo_mount)
+ (void) umount(tree);
+
+ (void) rmdir(tree);
+ return r;
+}
+
+static int create_subcgroup(pid_t pid) {
+ _cleanup_free_ char *cgroup = NULL;
+ const char *child;
+ int unified, r;
+
+ /* In the unified hierarchy inner nodes may only only contain
+ * subgroups, but not processes. Hence, if we running in the
+ * unified hierarchy and the container does the same, and we
+ * did not create a scope unit for the container move us and
+ * the container into two separate subcgroups. */
+
+ if (!arg_keep_unit)
+ return 0;
+
+ if (!arg_unified_cgroup_hierarchy)
+ return 0;
+
+ unified = cg_unified();
+ if (unified < 0)
+ return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
+ if (unified == 0)
+ return 0;
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get our control group: %m");
+
+ child = strjoina(cgroup, "/payload");
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, pid);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
+
+ child = strjoina(cgroup, "/supervisor");
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, 0);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
return 0;
}
@@ -4976,6 +5175,14 @@ int main(int argc, char *argv[]) {
if (r < 0)
goto finish;
+ r = sync_cgroup(pid);
+ if (r < 0)
+ goto finish;
+
+ r = create_subcgroup(pid);
+ if (r < 0)
+ goto finish;
+
r = chown_cgroup(pid);
if (r < 0)
goto finish;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-27 16:48:17 +0000