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-rw-r--r--src/basic/cgroup-util.c2189
1 files changed, 2189 insertions, 0 deletions
diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
new file mode 100644
index 0000000..f28bf18
--- /dev/null
+++ b/src/basic/cgroup-util.c
@@ -0,0 +1,2189 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <ftw.h>
+#include <limits.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/utsname.h>
+#include <sys/xattr.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "cgroup-util.h"
+#include "def.h"
+#include "dirent-util.h"
+#include "extract-word.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "log.h"
+#include "login-util.h"
+#include "macro.h"
+#include "missing_magic.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "set.h"
+#include "special.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "unit-name.h"
+#include "user-util.h"
+#include "xattr-util.h"
+
+static int cg_enumerate_items(const char *controller, const char *path, FILE **_f, const char *item) {
+ _cleanup_free_ char *fs = NULL;
+ FILE *f;
+ int r;
+
+ assert(_f);
+
+ r = cg_get_path(controller, path, item, &fs);
+ if (r < 0)
+ return r;
+
+ f = fopen(fs, "re");
+ if (!f)
+ return -errno;
+
+ *_f = f;
+ return 0;
+}
+
+int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
+ return cg_enumerate_items(controller, path, _f, "cgroup.procs");
+}
+
+int cg_read_pid(FILE *f, pid_t *_pid) {
+ unsigned long ul;
+
+ /* Note that the cgroup.procs might contain duplicates! See
+ * cgroups.txt for details. */
+
+ assert(f);
+ assert(_pid);
+
+ errno = 0;
+ if (fscanf(f, "%lu", &ul) != 1) {
+
+ if (feof(f))
+ return 0;
+
+ return errno_or_else(EIO);
+ }
+
+ if (ul <= 0)
+ return -EIO;
+
+ *_pid = (pid_t) ul;
+ return 1;
+}
+
+int cg_read_event(
+ const char *controller,
+ const char *path,
+ const char *event,
+ char **ret) {
+
+ _cleanup_free_ char *events = NULL, *content = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, "cgroup.events", &events);
+ if (r < 0)
+ return r;
+
+ r = read_full_file(events, &content, NULL);
+ if (r < 0)
+ return r;
+
+ for (const char *p = content;;) {
+ _cleanup_free_ char *line = NULL, *key = NULL, *val = NULL;
+ const char *q;
+
+ r = extract_first_word(&p, &line, "\n", 0);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -ENOENT;
+
+ q = line;
+ r = extract_first_word(&q, &key, " ", 0);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EINVAL;
+
+ if (!streq(key, event))
+ continue;
+
+ val = strdup(q);
+ if (!val)
+ return -ENOMEM;
+
+ *ret = TAKE_PTR(val);
+ return 0;
+ }
+}
+
+bool cg_ns_supported(void) {
+ static thread_local int enabled = -1;
+
+ if (enabled >= 0)
+ return enabled;
+
+ if (access("/proc/self/ns/cgroup", F_OK) < 0) {
+ if (errno != ENOENT)
+ log_debug_errno(errno, "Failed to check whether /proc/self/ns/cgroup is available, assuming not: %m");
+ enabled = false;
+ } else
+ enabled = true;
+
+ return enabled;
+}
+
+bool cg_freezer_supported(void) {
+ static thread_local int supported = -1;
+
+ if (supported >= 0)
+ return supported;
+
+ supported = cg_all_unified() > 0 && access("/sys/fs/cgroup/init.scope/cgroup.freeze", F_OK) == 0;
+
+ return supported;
+}
+
+int cg_enumerate_subgroups(const char *controller, const char *path, DIR **_d) {
+ _cleanup_free_ char *fs = NULL;
+ int r;
+ DIR *d;
+
+ assert(_d);
+
+ /* This is not recursive! */
+
+ r = cg_get_path(controller, path, NULL, &fs);
+ if (r < 0)
+ return r;
+
+ d = opendir(fs);
+ if (!d)
+ return -errno;
+
+ *_d = d;
+ return 0;
+}
+
+int cg_read_subgroup(DIR *d, char **fn) {
+ struct dirent *de;
+
+ assert(d);
+ assert(fn);
+
+ FOREACH_DIRENT_ALL(de, d, return -errno) {
+ char *b;
+
+ if (de->d_type != DT_DIR)
+ continue;
+
+ if (dot_or_dot_dot(de->d_name))
+ continue;
+
+ b = strdup(de->d_name);
+ if (!b)
+ return -ENOMEM;
+
+ *fn = b;
+ return 1;
+ }
+
+ return 0;
+}
+
+int cg_rmdir(const char *controller, const char *path) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, NULL, &p);
+ if (r < 0)
+ return r;
+
+ r = rmdir(p);
+ if (r < 0 && errno != ENOENT)
+ return -errno;
+
+ r = cg_hybrid_unified();
+ if (r <= 0)
+ return r;
+
+ if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
+ r = cg_rmdir(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
+ if (r < 0)
+ log_warning_errno(r, "Failed to remove compat systemd cgroup %s: %m", path);
+ }
+
+ return 0;
+}
+
+static int cg_kill_items(
+ const char *controller,
+ const char *path,
+ int sig,
+ CGroupFlags flags,
+ Set *s,
+ cg_kill_log_func_t log_kill,
+ void *userdata,
+ const char *item) {
+
+ _cleanup_set_free_ Set *allocated_set = NULL;
+ bool done = false;
+ int r, ret = 0, ret_log_kill = 0;
+ pid_t my_pid;
+
+ assert(sig >= 0);
+
+ /* Don't send SIGCONT twice. Also, SIGKILL always works even when process is suspended, hence don't send
+ * SIGCONT on SIGKILL. */
+ if (IN_SET(sig, SIGCONT, SIGKILL))
+ flags &= ~CGROUP_SIGCONT;
+
+ /* This goes through the tasks list and kills them all. This
+ * is repeated until no further processes are added to the
+ * tasks list, to properly handle forking processes */
+
+ if (!s) {
+ s = allocated_set = set_new(NULL);
+ if (!s)
+ return -ENOMEM;
+ }
+
+ my_pid = getpid_cached();
+
+ do {
+ _cleanup_fclose_ FILE *f = NULL;
+ pid_t pid = 0;
+ done = true;
+
+ r = cg_enumerate_items(controller, path, &f, item);
+ if (r < 0) {
+ if (ret >= 0 && r != -ENOENT)
+ return r;
+
+ return ret;
+ }
+
+ while ((r = cg_read_pid(f, &pid)) > 0) {
+
+ if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid)
+ continue;
+
+ if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid))
+ continue;
+
+ if (log_kill)
+ ret_log_kill = log_kill(pid, sig, userdata);
+
+ /* If we haven't killed this process yet, kill
+ * it */
+ if (kill(pid, sig) < 0) {
+ if (ret >= 0 && errno != ESRCH)
+ ret = -errno;
+ } else {
+ if (flags & CGROUP_SIGCONT)
+ (void) kill(pid, SIGCONT);
+
+ if (ret == 0) {
+ if (log_kill)
+ ret = ret_log_kill;
+ else
+ ret = 1;
+ }
+ }
+
+ done = false;
+
+ r = set_put(s, PID_TO_PTR(pid));
+ if (r < 0) {
+ if (ret >= 0)
+ return r;
+
+ return ret;
+ }
+ }
+
+ if (r < 0) {
+ if (ret >= 0)
+ return r;
+
+ return ret;
+ }
+
+ /* To avoid racing against processes which fork
+ * quicker than we can kill them we repeat this until
+ * no new pids need to be killed. */
+
+ } while (!done);
+
+ return ret;
+}
+
+int cg_kill(
+ const char *controller,
+ const char *path,
+ int sig,
+ CGroupFlags flags,
+ Set *s,
+ cg_kill_log_func_t log_kill,
+ void *userdata) {
+ int r;
+
+ r = cg_kill_items(controller, path, sig, flags, s, log_kill, userdata, "cgroup.procs");
+ if (r < 0 || sig != SIGKILL)
+ return r;
+
+ /* Only in case of killing with SIGKILL and when using cgroupsv2, kill remaining threads manually as
+ a workaround for kernel bug. It was fixed in 5.2-rc5 (c03cd7738a83), backported to 4.19.66
+ (4340d175b898) and 4.14.138 (feb6b123b7dd). */
+ r = cg_unified_controller(controller);
+ if (r <= 0)
+ return r;
+
+ return cg_kill_items(controller, path, sig, flags, s, log_kill, userdata, "cgroup.threads");
+}
+
+int cg_kill_recursive(
+ const char *controller,
+ const char *path,
+ int sig,
+ CGroupFlags flags,
+ Set *s,
+ cg_kill_log_func_t log_kill,
+ void *userdata) {
+
+ _cleanup_set_free_ Set *allocated_set = NULL;
+ _cleanup_closedir_ DIR *d = NULL;
+ int r, ret;
+ char *fn;
+
+ assert(path);
+ assert(sig >= 0);
+
+ if (!s) {
+ s = allocated_set = set_new(NULL);
+ if (!s)
+ return -ENOMEM;
+ }
+
+ ret = cg_kill(controller, path, sig, flags, s, log_kill, userdata);
+
+ r = cg_enumerate_subgroups(controller, path, &d);
+ if (r < 0) {
+ if (ret >= 0 && r != -ENOENT)
+ return r;
+
+ return ret;
+ }
+
+ while ((r = cg_read_subgroup(d, &fn)) > 0) {
+ _cleanup_free_ char *p = NULL;
+
+ p = path_join(empty_to_root(path), fn);
+ free(fn);
+ if (!p)
+ return -ENOMEM;
+
+ r = cg_kill_recursive(controller, p, sig, flags, s, log_kill, userdata);
+ if (r != 0 && ret >= 0)
+ ret = r;
+ }
+ if (ret >= 0 && r < 0)
+ ret = r;
+
+ if (flags & CGROUP_REMOVE) {
+ r = cg_rmdir(controller, path);
+ if (r < 0 && ret >= 0 && !IN_SET(r, -ENOENT, -EBUSY))
+ return r;
+ }
+
+ return ret;
+}
+
+static const char *controller_to_dirname(const char *controller) {
+ const char *e;
+
+ assert(controller);
+
+ /* Converts a controller name to the directory name below
+ * /sys/fs/cgroup/ we want to mount it to. Effectively, this
+ * just cuts off the name= prefixed used for named
+ * hierarchies, if it is specified. */
+
+ if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
+ if (cg_hybrid_unified() > 0)
+ controller = SYSTEMD_CGROUP_CONTROLLER_HYBRID;
+ else
+ controller = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
+ }
+
+ e = startswith(controller, "name=");
+ if (e)
+ return e;
+
+ return controller;
+}
+
+static int join_path_legacy(const char *controller, const char *path, const char *suffix, char **fs) {
+ const char *dn;
+ char *t = NULL;
+
+ assert(fs);
+ assert(controller);
+
+ dn = controller_to_dirname(controller);
+
+ if (isempty(path) && isempty(suffix))
+ t = path_join("/sys/fs/cgroup", dn);
+ else if (isempty(path))
+ t = path_join("/sys/fs/cgroup", dn, suffix);
+ else if (isempty(suffix))
+ t = path_join("/sys/fs/cgroup", dn, path);
+ else
+ t = path_join("/sys/fs/cgroup", dn, path, suffix);
+ if (!t)
+ return -ENOMEM;
+
+ *fs = t;
+ return 0;
+}
+
+static int join_path_unified(const char *path, const char *suffix, char **fs) {
+ char *t;
+
+ assert(fs);
+
+ if (isempty(path) && isempty(suffix))
+ t = strdup("/sys/fs/cgroup");
+ else if (isempty(path))
+ t = path_join("/sys/fs/cgroup", suffix);
+ else if (isempty(suffix))
+ t = path_join("/sys/fs/cgroup", path);
+ else
+ t = path_join("/sys/fs/cgroup", path, suffix);
+ if (!t)
+ return -ENOMEM;
+
+ *fs = t;
+ return 0;
+}
+
+int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
+ int r;
+
+ assert(fs);
+
+ if (!controller) {
+ char *t;
+
+ /* If no controller is specified, we return the path
+ * *below* the controllers, without any prefix. */
+
+ if (!path && !suffix)
+ return -EINVAL;
+
+ if (!suffix)
+ t = strdup(path);
+ else if (!path)
+ t = strdup(suffix);
+ else
+ t = path_join(path, suffix);
+ if (!t)
+ return -ENOMEM;
+
+ *fs = path_simplify(t, false);
+ return 0;
+ }
+
+ if (!cg_controller_is_valid(controller))
+ return -EINVAL;
+
+ r = cg_all_unified();
+ if (r < 0)
+ return r;
+ if (r > 0)
+ r = join_path_unified(path, suffix, fs);
+ else
+ r = join_path_legacy(controller, path, suffix, fs);
+ if (r < 0)
+ return r;
+
+ path_simplify(*fs, false);
+ return 0;
+}
+
+static int controller_is_accessible(const char *controller) {
+ int r;
+
+ assert(controller);
+
+ /* Checks whether a specific controller is accessible,
+ * i.e. its hierarchy mounted. In the unified hierarchy all
+ * controllers are considered accessible, except for the named
+ * hierarchies */
+
+ if (!cg_controller_is_valid(controller))
+ return -EINVAL;
+
+ r = cg_all_unified();
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ /* We don't support named hierarchies if we are using
+ * the unified hierarchy. */
+
+ if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+ return 0;
+
+ if (startswith(controller, "name="))
+ return -EOPNOTSUPP;
+
+ } else {
+ const char *cc, *dn;
+
+ dn = controller_to_dirname(controller);
+ cc = strjoina("/sys/fs/cgroup/", dn);
+
+ if (laccess(cc, F_OK) < 0)
+ return -errno;
+ }
+
+ return 0;
+}
+
+int cg_get_path_and_check(const char *controller, const char *path, const char *suffix, char **fs) {
+ int r;
+
+ assert(controller);
+ assert(fs);
+
+ /* Check if the specified controller is actually accessible */
+ r = controller_is_accessible(controller);
+ if (r < 0)
+ return r;
+
+ return cg_get_path(controller, path, suffix, fs);
+}
+
+int cg_set_xattr(const char *controller, const char *path, const char *name, const void *value, size_t size, int flags) {
+ _cleanup_free_ char *fs = NULL;
+ int r;
+
+ assert(path);
+ assert(name);
+ assert(value || size <= 0);
+
+ r = cg_get_path(controller, path, NULL, &fs);
+ if (r < 0)
+ return r;
+
+ if (setxattr(fs, name, value, size, flags) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int cg_get_xattr(const char *controller, const char *path, const char *name, void *value, size_t size) {
+ _cleanup_free_ char *fs = NULL;
+ ssize_t n;
+ int r;
+
+ assert(path);
+ assert(name);
+
+ r = cg_get_path(controller, path, NULL, &fs);
+ if (r < 0)
+ return r;
+
+ n = getxattr(fs, name, value, size);
+ if (n < 0)
+ return -errno;
+
+ return (int) n;
+}
+
+int cg_get_xattr_malloc(const char *controller, const char *path, const char *name, char **ret) {
+ _cleanup_free_ char *fs = NULL;
+ int r;
+
+ assert(path);
+ assert(name);
+
+ r = cg_get_path(controller, path, NULL, &fs);
+ if (r < 0)
+ return r;
+
+ r = getxattr_malloc(fs, name, ret, false);
+ if (r < 0)
+ return r;
+
+ return r;
+}
+
+int cg_remove_xattr(const char *controller, const char *path, const char *name) {
+ _cleanup_free_ char *fs = NULL;
+ int r;
+
+ assert(path);
+ assert(name);
+
+ r = cg_get_path(controller, path, NULL, &fs);
+ if (r < 0)
+ return r;
+
+ if (removexattr(fs, name) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int cg_pid_get_path(const char *controller, pid_t pid, char **ret_path) {
+ _cleanup_fclose_ FILE *f = NULL;
+ const char *fs, *controller_str;
+ int unified, r;
+
+ assert(pid >= 0);
+ assert(ret_path);
+
+ if (controller) {
+ if (!cg_controller_is_valid(controller))
+ return -EINVAL;
+ } else
+ controller = SYSTEMD_CGROUP_CONTROLLER;
+
+ unified = cg_unified_controller(controller);
+ if (unified < 0)
+ return unified;
+ if (unified == 0) {
+ if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+ controller_str = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
+ else
+ controller_str = controller;
+ }
+
+ fs = procfs_file_alloca(pid, "cgroup");
+ r = fopen_unlocked(fs, "re", &f);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ char *e;
+
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -ENODATA;
+
+ if (unified) {
+ e = startswith(line, "0:");
+ if (!e)
+ continue;
+
+ e = strchr(e, ':');
+ if (!e)
+ continue;
+ } else {
+ char *l;
+
+ l = strchr(line, ':');
+ if (!l)
+ continue;
+
+ l++;
+ e = strchr(l, ':');
+ if (!e)
+ continue;
+ *e = 0;
+
+ r = string_contains_word(l, ",", controller_str);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+ }
+
+ char *path = strdup(e + 1);
+ if (!path)
+ return -ENOMEM;
+
+ /* Truncate suffix indicating the process is a zombie */
+ e = endswith(path, " (deleted)");
+ if (e)
+ *e = 0;
+
+ *ret_path = path;
+ return 0;
+ }
+}
+
+int cg_install_release_agent(const char *controller, const char *agent) {
+ _cleanup_free_ char *fs = NULL, *contents = NULL;
+ const char *sc;
+ int r;
+
+ assert(agent);
+
+ r = cg_unified_controller(controller);
+ if (r < 0)
+ return r;
+ if (r > 0) /* doesn't apply to unified hierarchy */
+ return -EOPNOTSUPP;
+
+ r = cg_get_path(controller, NULL, "release_agent", &fs);
+ if (r < 0)
+ return r;
+
+ r = read_one_line_file(fs, &contents);
+ if (r < 0)
+ return r;
+
+ sc = strstrip(contents);
+ if (isempty(sc)) {
+ r = write_string_file(fs, agent, WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return r;
+ } else if (!path_equal(sc, agent))
+ return -EEXIST;
+
+ fs = mfree(fs);
+ r = cg_get_path(controller, NULL, "notify_on_release", &fs);
+ if (r < 0)
+ return r;
+
+ contents = mfree(contents);
+ r = read_one_line_file(fs, &contents);
+ if (r < 0)
+ return r;
+
+ sc = strstrip(contents);
+ if (streq(sc, "0")) {
+ r = write_string_file(fs, "1", WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return r;
+
+ return 1;
+ }
+
+ if (!streq(sc, "1"))
+ return -EIO;
+
+ return 0;
+}
+
+int cg_uninstall_release_agent(const char *controller) {
+ _cleanup_free_ char *fs = NULL;
+ int r;
+
+ r = cg_unified_controller(controller);
+ if (r < 0)
+ return r;
+ if (r > 0) /* Doesn't apply to unified hierarchy */
+ return -EOPNOTSUPP;
+
+ r = cg_get_path(controller, NULL, "notify_on_release", &fs);
+ if (r < 0)
+ return r;
+
+ r = write_string_file(fs, "0", WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return r;
+
+ fs = mfree(fs);
+
+ r = cg_get_path(controller, NULL, "release_agent", &fs);
+ if (r < 0)
+ return r;
+
+ r = write_string_file(fs, "", WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int cg_is_empty(const char *controller, const char *path) {
+ _cleanup_fclose_ FILE *f = NULL;
+ pid_t pid;
+ int r;
+
+ assert(path);
+
+ r = cg_enumerate_processes(controller, path, &f);
+ if (r == -ENOENT)
+ return true;
+ if (r < 0)
+ return r;
+
+ r = cg_read_pid(f, &pid);
+ if (r < 0)
+ return r;
+
+ return r == 0;
+}
+
+int cg_is_empty_recursive(const char *controller, const char *path) {
+ int r;
+
+ assert(path);
+
+ /* The root cgroup is always populated */
+ if (controller && empty_or_root(path))
+ return false;
+
+ r = cg_unified_controller(controller);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ _cleanup_free_ char *t = NULL;
+
+ /* On the unified hierarchy we can check empty state
+ * via the "populated" attribute of "cgroup.events". */
+
+ r = cg_read_event(controller, path, "populated", &t);
+ if (r == -ENOENT)
+ return true;
+ if (r < 0)
+ return r;
+
+ return streq(t, "0");
+ } else {
+ _cleanup_closedir_ DIR *d = NULL;
+ char *fn;
+
+ r = cg_is_empty(controller, path);
+ if (r <= 0)
+ return r;
+
+ r = cg_enumerate_subgroups(controller, path, &d);
+ if (r == -ENOENT)
+ return true;
+ if (r < 0)
+ return r;
+
+ while ((r = cg_read_subgroup(d, &fn)) > 0) {
+ _cleanup_free_ char *p = NULL;
+
+ p = path_join(path, fn);
+ free(fn);
+ if (!p)
+ return -ENOMEM;
+
+ r = cg_is_empty_recursive(controller, p);
+ if (r <= 0)
+ return r;
+ }
+ if (r < 0)
+ return r;
+
+ return true;
+ }
+}
+
+int cg_split_spec(const char *spec, char **ret_controller, char **ret_path) {
+ _cleanup_free_ char *controller = NULL, *path = NULL;
+
+ assert(spec);
+
+ if (*spec == '/') {
+ if (!path_is_normalized(spec))
+ return -EINVAL;
+
+ if (ret_path) {
+ path = strdup(spec);
+ if (!path)
+ return -ENOMEM;
+
+ path_simplify(path, false);
+ }
+
+ } else {
+ const char *e;
+
+ e = strchr(spec, ':');
+ if (e) {
+ controller = strndup(spec, e-spec);
+ if (!controller)
+ return -ENOMEM;
+ if (!cg_controller_is_valid(controller))
+ return -EINVAL;
+
+ if (!isempty(e + 1)) {
+ path = strdup(e+1);
+ if (!path)
+ return -ENOMEM;
+
+ if (!path_is_normalized(path) ||
+ !path_is_absolute(path))
+ return -EINVAL;
+
+ path_simplify(path, false);
+ }
+
+ } else {
+ if (!cg_controller_is_valid(spec))
+ return -EINVAL;
+
+ if (ret_controller) {
+ controller = strdup(spec);
+ if (!controller)
+ return -ENOMEM;
+ }
+ }
+ }
+
+ if (ret_controller)
+ *ret_controller = TAKE_PTR(controller);
+ if (ret_path)
+ *ret_path = TAKE_PTR(path);
+ return 0;
+}
+
+int cg_mangle_path(const char *path, char **result) {
+ _cleanup_free_ char *c = NULL, *p = NULL;
+ char *t;
+ int r;
+
+ assert(path);
+ assert(result);
+
+ /* First, check if it already is a filesystem path */
+ if (path_startswith(path, "/sys/fs/cgroup")) {
+
+ t = strdup(path);
+ if (!t)
+ return -ENOMEM;
+
+ *result = path_simplify(t, false);
+ return 0;
+ }
+
+ /* Otherwise, treat it as cg spec */
+ r = cg_split_spec(path, &c, &p);
+ if (r < 0)
+ return r;
+
+ return cg_get_path(c ?: SYSTEMD_CGROUP_CONTROLLER, p ?: "/", NULL, result);
+}
+
+int cg_get_root_path(char **path) {
+ char *p, *e;
+ int r;
+
+ assert(path);
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &p);
+ if (r < 0)
+ return r;
+
+ e = endswith(p, "/" SPECIAL_INIT_SCOPE);
+ if (!e)
+ e = endswith(p, "/" SPECIAL_SYSTEM_SLICE); /* legacy */
+ if (!e)
+ e = endswith(p, "/system"); /* even more legacy */
+ if (e)
+ *e = 0;
+
+ *path = p;
+ return 0;
+}
+
+int cg_shift_path(const char *cgroup, const char *root, const char **shifted) {
+ _cleanup_free_ char *rt = NULL;
+ char *p;
+ int r;
+
+ assert(cgroup);
+ assert(shifted);
+
+ if (!root) {
+ /* If the root was specified let's use that, otherwise
+ * let's determine it from PID 1 */
+
+ r = cg_get_root_path(&rt);
+ if (r < 0)
+ return r;
+
+ root = rt;
+ }
+
+ p = path_startswith(cgroup, root);
+ if (p && p > cgroup)
+ *shifted = p - 1;
+ else
+ *shifted = cgroup;
+
+ return 0;
+}
+
+int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
+ _cleanup_free_ char *raw = NULL;
+ const char *c;
+ int r;
+
+ assert(pid >= 0);
+ assert(cgroup);
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &raw);
+ if (r < 0)
+ return r;
+
+ r = cg_shift_path(raw, root, &c);
+ if (r < 0)
+ return r;
+
+ if (c == raw)
+ *cgroup = TAKE_PTR(raw);
+ else {
+ char *n;
+
+ n = strdup(c);
+ if (!n)
+ return -ENOMEM;
+
+ *cgroup = n;
+ }
+
+ return 0;
+}
+
+int cg_path_decode_unit(const char *cgroup, char **unit) {
+ char *c, *s;
+ size_t n;
+
+ assert(cgroup);
+ assert(unit);
+
+ n = strcspn(cgroup, "/");
+ if (n < 3)
+ return -ENXIO;
+
+ c = strndupa(cgroup, n);
+ c = cg_unescape(c);
+
+ if (!unit_name_is_valid(c, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
+ return -ENXIO;
+
+ s = strdup(c);
+ if (!s)
+ return -ENOMEM;
+
+ *unit = s;
+ return 0;
+}
+
+static bool valid_slice_name(const char *p, size_t n) {
+
+ if (!p)
+ return false;
+
+ if (n < STRLEN("x.slice"))
+ return false;
+
+ if (memcmp(p + n - 6, ".slice", 6) == 0) {
+ char buf[n+1], *c;
+
+ memcpy(buf, p, n);
+ buf[n] = 0;
+
+ c = cg_unescape(buf);
+
+ return unit_name_is_valid(c, UNIT_NAME_PLAIN);
+ }
+
+ return false;
+}
+
+static const char *skip_slices(const char *p) {
+ assert(p);
+
+ /* Skips over all slice assignments */
+
+ for (;;) {
+ size_t n;
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (!valid_slice_name(p, n))
+ return p;
+
+ p += n;
+ }
+}
+
+int cg_path_get_unit(const char *path, char **ret) {
+ const char *e;
+ char *unit;
+ int r;
+
+ assert(path);
+ assert(ret);
+
+ e = skip_slices(path);
+
+ r = cg_path_decode_unit(e, &unit);
+ if (r < 0)
+ return r;
+
+ /* We skipped over the slices, don't accept any now */
+ if (endswith(unit, ".slice")) {
+ free(unit);
+ return -ENXIO;
+ }
+
+ *ret = unit;
+ return 0;
+}
+
+int cg_pid_get_unit(pid_t pid, char **unit) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(unit);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_unit(cgroup, unit);
+}
+
+/**
+ * Skip session-*.scope, but require it to be there.
+ */
+static const char *skip_session(const char *p) {
+ size_t n;
+
+ if (isempty(p))
+ return NULL;
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (n < STRLEN("session-x.scope"))
+ return NULL;
+
+ if (memcmp(p, "session-", 8) == 0 && memcmp(p + n - 6, ".scope", 6) == 0) {
+ char buf[n - 8 - 6 + 1];
+
+ memcpy(buf, p + 8, n - 8 - 6);
+ buf[n - 8 - 6] = 0;
+
+ /* Note that session scopes never need unescaping,
+ * since they cannot conflict with the kernel's own
+ * names, hence we don't need to call cg_unescape()
+ * here. */
+
+ if (!session_id_valid(buf))
+ return false;
+
+ p += n;
+ p += strspn(p, "/");
+ return p;
+ }
+
+ return NULL;
+}
+
+/**
+ * Skip user@*.service, but require it to be there.
+ */
+static const char *skip_user_manager(const char *p) {
+ size_t n;
+
+ if (isempty(p))
+ return NULL;
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (n < STRLEN("user@x.service"))
+ return NULL;
+
+ if (memcmp(p, "user@", 5) == 0 && memcmp(p + n - 8, ".service", 8) == 0) {
+ char buf[n - 5 - 8 + 1];
+
+ memcpy(buf, p + 5, n - 5 - 8);
+ buf[n - 5 - 8] = 0;
+
+ /* Note that user manager services never need unescaping,
+ * since they cannot conflict with the kernel's own
+ * names, hence we don't need to call cg_unescape()
+ * here. */
+
+ if (parse_uid(buf, NULL) < 0)
+ return NULL;
+
+ p += n;
+ p += strspn(p, "/");
+
+ return p;
+ }
+
+ return NULL;
+}
+
+static const char *skip_user_prefix(const char *path) {
+ const char *e, *t;
+
+ assert(path);
+
+ /* Skip slices, if there are any */
+ e = skip_slices(path);
+
+ /* Skip the user manager, if it's in the path now... */
+ t = skip_user_manager(e);
+ if (t)
+ return t;
+
+ /* Alternatively skip the user session if it is in the path... */
+ return skip_session(e);
+}
+
+int cg_path_get_user_unit(const char *path, char **ret) {
+ const char *t;
+
+ assert(path);
+ assert(ret);
+
+ t = skip_user_prefix(path);
+ if (!t)
+ return -ENXIO;
+
+ /* And from here on it looks pretty much the same as for a system unit, hence let's use the same
+ * parser. */
+ return cg_path_get_unit(t, ret);
+}
+
+int cg_pid_get_user_unit(pid_t pid, char **unit) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(unit);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_user_unit(cgroup, unit);
+}
+
+int cg_path_get_machine_name(const char *path, char **machine) {
+ _cleanup_free_ char *u = NULL;
+ const char *sl;
+ int r;
+
+ r = cg_path_get_unit(path, &u);
+ if (r < 0)
+ return r;
+
+ sl = strjoina("/run/systemd/machines/unit:", u);
+ return readlink_malloc(sl, machine);
+}
+
+int cg_pid_get_machine_name(pid_t pid, char **machine) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(machine);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_machine_name(cgroup, machine);
+}
+
+int cg_path_get_session(const char *path, char **session) {
+ _cleanup_free_ char *unit = NULL;
+ char *start, *end;
+ int r;
+
+ assert(path);
+
+ r = cg_path_get_unit(path, &unit);
+ if (r < 0)
+ return r;
+
+ start = startswith(unit, "session-");
+ if (!start)
+ return -ENXIO;
+ end = endswith(start, ".scope");
+ if (!end)
+ return -ENXIO;
+
+ *end = 0;
+ if (!session_id_valid(start))
+ return -ENXIO;
+
+ if (session) {
+ char *rr;
+
+ rr = strdup(start);
+ if (!rr)
+ return -ENOMEM;
+
+ *session = rr;
+ }
+
+ return 0;
+}
+
+int cg_pid_get_session(pid_t pid, char **session) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_session(cgroup, session);
+}
+
+int cg_path_get_owner_uid(const char *path, uid_t *uid) {
+ _cleanup_free_ char *slice = NULL;
+ char *start, *end;
+ int r;
+
+ assert(path);
+
+ r = cg_path_get_slice(path, &slice);
+ if (r < 0)
+ return r;
+
+ start = startswith(slice, "user-");
+ if (!start)
+ return -ENXIO;
+ end = endswith(start, ".slice");
+ if (!end)
+ return -ENXIO;
+
+ *end = 0;
+ if (parse_uid(start, uid) < 0)
+ return -ENXIO;
+
+ return 0;
+}
+
+int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_owner_uid(cgroup, uid);
+}
+
+int cg_path_get_slice(const char *p, char **slice) {
+ const char *e = NULL;
+
+ assert(p);
+ assert(slice);
+
+ /* Finds the right-most slice unit from the beginning, but
+ * stops before we come to the first non-slice unit. */
+
+ for (;;) {
+ size_t n;
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (!valid_slice_name(p, n)) {
+
+ if (!e) {
+ char *s;
+
+ s = strdup(SPECIAL_ROOT_SLICE);
+ if (!s)
+ return -ENOMEM;
+
+ *slice = s;
+ return 0;
+ }
+
+ return cg_path_decode_unit(e, slice);
+ }
+
+ e = p;
+ p += n;
+ }
+}
+
+int cg_pid_get_slice(pid_t pid, char **slice) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(slice);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_slice(cgroup, slice);
+}
+
+int cg_path_get_user_slice(const char *p, char **slice) {
+ const char *t;
+ assert(p);
+ assert(slice);
+
+ t = skip_user_prefix(p);
+ if (!t)
+ return -ENXIO;
+
+ /* And now it looks pretty much the same as for a system
+ * slice, so let's just use the same parser from here on. */
+ return cg_path_get_slice(t, slice);
+}
+
+int cg_pid_get_user_slice(pid_t pid, char **slice) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(slice);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_user_slice(cgroup, slice);
+}
+
+char *cg_escape(const char *p) {
+ bool need_prefix = false;
+
+ /* This implements very minimal escaping for names to be used
+ * as file names in the cgroup tree: any name which might
+ * conflict with a kernel name or is prefixed with '_' is
+ * prefixed with a '_'. That way, when reading cgroup names it
+ * is sufficient to remove a single prefixing underscore if
+ * there is one. */
+
+ /* The return value of this function (unlike cg_unescape())
+ * needs free()! */
+
+ if (IN_SET(p[0], 0, '_', '.') ||
+ STR_IN_SET(p, "notify_on_release", "release_agent", "tasks") ||
+ startswith(p, "cgroup."))
+ need_prefix = true;
+ else {
+ const char *dot;
+
+ dot = strrchr(p, '.');
+ if (dot) {
+ CGroupController c;
+ size_t l = dot - p;
+
+ for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
+ const char *n;
+
+ n = cgroup_controller_to_string(c);
+
+ if (l != strlen(n))
+ continue;
+
+ if (memcmp(p, n, l) != 0)
+ continue;
+
+ need_prefix = true;
+ break;
+ }
+ }
+ }
+
+ if (need_prefix)
+ return strjoin("_", p);
+
+ return strdup(p);
+}
+
+char *cg_unescape(const char *p) {
+ assert(p);
+
+ /* The return value of this function (unlike cg_escape())
+ * doesn't need free()! */
+
+ if (p[0] == '_')
+ return (char*) p+1;
+
+ return (char*) p;
+}
+
+#define CONTROLLER_VALID \
+ DIGITS LETTERS \
+ "_"
+
+bool cg_controller_is_valid(const char *p) {
+ const char *t, *s;
+
+ if (!p)
+ return false;
+
+ if (streq(p, SYSTEMD_CGROUP_CONTROLLER))
+ return true;
+
+ s = startswith(p, "name=");
+ if (s)
+ p = s;
+
+ if (IN_SET(*p, 0, '_'))
+ return false;
+
+ for (t = p; *t; t++)
+ if (!strchr(CONTROLLER_VALID, *t))
+ return false;
+
+ if (t - p > FILENAME_MAX)
+ return false;
+
+ return true;
+}
+
+int cg_slice_to_path(const char *unit, char **ret) {
+ _cleanup_free_ char *p = NULL, *s = NULL, *e = NULL;
+ const char *dash;
+ int r;
+
+ assert(unit);
+ assert(ret);
+
+ if (streq(unit, SPECIAL_ROOT_SLICE)) {
+ char *x;
+
+ x = strdup("");
+ if (!x)
+ return -ENOMEM;
+ *ret = x;
+ return 0;
+ }
+
+ if (!unit_name_is_valid(unit, UNIT_NAME_PLAIN))
+ return -EINVAL;
+
+ if (!endswith(unit, ".slice"))
+ return -EINVAL;
+
+ r = unit_name_to_prefix(unit, &p);
+ if (r < 0)
+ return r;
+
+ dash = strchr(p, '-');
+
+ /* Don't allow initial dashes */
+ if (dash == p)
+ return -EINVAL;
+
+ while (dash) {
+ _cleanup_free_ char *escaped = NULL;
+ char n[dash - p + sizeof(".slice")];
+
+#if HAS_FEATURE_MEMORY_SANITIZER
+ /* msan doesn't instrument stpncpy, so it thinks
+ * n is later used uninitialized:
+ * https://github.com/google/sanitizers/issues/926
+ */
+ zero(n);
+#endif
+
+ /* Don't allow trailing or double dashes */
+ if (IN_SET(dash[1], 0, '-'))
+ return -EINVAL;
+
+ strcpy(stpncpy(n, p, dash - p), ".slice");
+ if (!unit_name_is_valid(n, UNIT_NAME_PLAIN))
+ return -EINVAL;
+
+ escaped = cg_escape(n);
+ if (!escaped)
+ return -ENOMEM;
+
+ if (!strextend(&s, escaped, "/", NULL))
+ return -ENOMEM;
+
+ dash = strchr(dash+1, '-');
+ }
+
+ e = cg_escape(unit);
+ if (!e)
+ return -ENOMEM;
+
+ if (!strextend(&s, e, NULL))
+ return -ENOMEM;
+
+ *ret = TAKE_PTR(s);
+
+ return 0;
+}
+
+int cg_set_attribute(const char *controller, const char *path, const char *attribute, const char *value) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, attribute, &p);
+ if (r < 0)
+ return r;
+
+ return write_string_file(p, value, WRITE_STRING_FILE_DISABLE_BUFFER);
+}
+
+int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, attribute, &p);
+ if (r < 0)
+ return r;
+
+ return read_one_line_file(p, ret);
+}
+
+int cg_get_attribute_as_uint64(const char *controller, const char *path, const char *attribute, uint64_t *ret) {
+ _cleanup_free_ char *value = NULL;
+ uint64_t v;
+ int r;
+
+ assert(ret);
+
+ r = cg_get_attribute(controller, path, attribute, &value);
+ if (r == -ENOENT)
+ return -ENODATA;
+ if (r < 0)
+ return r;
+
+ if (streq(value, "max")) {
+ *ret = CGROUP_LIMIT_MAX;
+ return 0;
+ }
+
+ r = safe_atou64(value, &v);
+ if (r < 0)
+ return r;
+
+ *ret = v;
+ return 0;
+}
+
+int cg_get_attribute_as_bool(const char *controller, const char *path, const char *attribute, bool *ret) {
+ _cleanup_free_ char *value = NULL;
+ int r;
+
+ assert(ret);
+
+ r = cg_get_attribute(controller, path, attribute, &value);
+ if (r == -ENOENT)
+ return -ENODATA;
+ if (r < 0)
+ return r;
+
+ r = parse_boolean(value);
+ if (r < 0)
+ return r;
+
+ *ret = r;
+ return 0;
+}
+
+int cg_get_keyed_attribute_full(
+ const char *controller,
+ const char *path,
+ const char *attribute,
+ char **keys,
+ char **ret_values,
+ CGroupKeyMode mode) {
+
+ _cleanup_free_ char *filename = NULL, *contents = NULL;
+ const char *p;
+ size_t n, i, n_done = 0;
+ char **v;
+ int r;
+
+ /* Reads one or more fields of a cgroup v2 keyed attribute file. The 'keys' parameter should be an strv with
+ * all keys to retrieve. The 'ret_values' parameter should be passed as string size with the same number of
+ * entries as 'keys'. On success each entry will be set to the value of the matching key.
+ *
+ * If the attribute file doesn't exist at all returns ENOENT, if any key is not found returns ENXIO. If mode
+ * is set to GG_KEY_MODE_GRACEFUL we ignore missing keys and return those that were parsed successfully. */
+
+ r = cg_get_path(controller, path, attribute, &filename);
+ if (r < 0)
+ return r;
+
+ r = read_full_file(filename, &contents, NULL);
+ if (r < 0)
+ return r;
+
+ n = strv_length(keys);
+ if (n == 0) /* No keys to retrieve? That's easy, we are done then */
+ return 0;
+
+ /* Let's build this up in a temporary array for now in order not to clobber the return parameter on failure */
+ v = newa0(char*, n);
+
+ for (p = contents; *p;) {
+ const char *w = NULL;
+
+ for (i = 0; i < n; i++)
+ if (!v[i]) {
+ w = first_word(p, keys[i]);
+ if (w)
+ break;
+ }
+
+ if (w) {
+ size_t l;
+
+ l = strcspn(w, NEWLINE);
+ v[i] = strndup(w, l);
+ if (!v[i]) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ n_done++;
+ if (n_done >= n)
+ goto done;
+
+ p = w + l;
+ } else
+ p += strcspn(p, NEWLINE);
+
+ p += strspn(p, NEWLINE);
+ }
+
+ if (mode & CG_KEY_MODE_GRACEFUL)
+ goto done;
+
+ r = -ENXIO;
+
+fail:
+ for (i = 0; i < n; i++)
+ free(v[i]);
+
+ return r;
+
+done:
+ memcpy(ret_values, v, sizeof(char*) * n);
+ if (mode & CG_KEY_MODE_GRACEFUL)
+ return n_done;
+
+ return 0;
+}
+
+int cg_mask_to_string(CGroupMask mask, char **ret) {
+ _cleanup_free_ char *s = NULL;
+ size_t n = 0, allocated = 0;
+ bool space = false;
+ CGroupController c;
+
+ assert(ret);
+
+ if (mask == 0) {
+ *ret = NULL;
+ return 0;
+ }
+
+ for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
+ const char *k;
+ size_t l;
+
+ if (!FLAGS_SET(mask, CGROUP_CONTROLLER_TO_MASK(c)))
+ continue;
+
+ k = cgroup_controller_to_string(c);
+ l = strlen(k);
+
+ if (!GREEDY_REALLOC(s, allocated, n + space + l + 1))
+ return -ENOMEM;
+
+ if (space)
+ s[n] = ' ';
+ memcpy(s + n + space, k, l);
+ n += space + l;
+
+ space = true;
+ }
+
+ assert(s);
+
+ s[n] = 0;
+ *ret = TAKE_PTR(s);
+
+ return 0;
+}
+
+int cg_mask_from_string(const char *value, CGroupMask *ret) {
+ CGroupMask m = 0;
+
+ assert(ret);
+ assert(value);
+
+ for (;;) {
+ _cleanup_free_ char *n = NULL;
+ CGroupController v;
+ int r;
+
+ r = extract_first_word(&value, &n, NULL, 0);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ v = cgroup_controller_from_string(n);
+ if (v < 0)
+ continue;
+
+ m |= CGROUP_CONTROLLER_TO_MASK(v);
+ }
+
+ *ret = m;
+ return 0;
+}
+
+int cg_mask_supported(CGroupMask *ret) {
+ CGroupMask mask;
+ int r;
+
+ /* Determines the mask of supported cgroup controllers. Only includes controllers we can make sense of and that
+ * are actually accessible. Only covers real controllers, i.e. not the CGROUP_CONTROLLER_BPF_xyz
+ * pseudo-controllers. */
+
+ r = cg_all_unified();
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ _cleanup_free_ char *root = NULL, *controllers = NULL, *path = NULL;
+
+ /* In the unified hierarchy we can read the supported and accessible controllers from
+ * the top-level cgroup attribute */
+
+ r = cg_get_root_path(&root);
+ if (r < 0)
+ return r;
+
+ r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, root, "cgroup.controllers", &path);
+ if (r < 0)
+ return r;
+
+ r = read_one_line_file(path, &controllers);
+ if (r < 0)
+ return r;
+
+ r = cg_mask_from_string(controllers, &mask);
+ if (r < 0)
+ return r;
+
+ /* Mask controllers that are not supported in unified hierarchy. */
+ mask &= CGROUP_MASK_V2;
+
+ } else {
+ CGroupController c;
+
+ /* In the legacy hierarchy, we check which hierarchies are mounted. */
+
+ mask = 0;
+ for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
+ CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
+ const char *n;
+
+ if (!FLAGS_SET(CGROUP_MASK_V1, bit))
+ continue;
+
+ n = cgroup_controller_to_string(c);
+ if (controller_is_accessible(n) >= 0)
+ mask |= bit;
+ }
+ }
+
+ *ret = mask;
+ return 0;
+}
+
+int cg_kernel_controllers(Set **ret) {
+ _cleanup_set_free_free_ Set *controllers = NULL;
+ _cleanup_fclose_ FILE *f = NULL;
+ int r;
+
+ assert(ret);
+
+ /* Determines the full list of kernel-known controllers. Might include controllers we don't actually support
+ * and controllers that aren't currently accessible (because not mounted). This does not include "name="
+ * pseudo-controllers. */
+
+ controllers = set_new(&string_hash_ops);
+ if (!controllers)
+ return -ENOMEM;
+
+ r = fopen_unlocked("/proc/cgroups", "re", &f);
+ if (r == -ENOENT) {
+ *ret = NULL;
+ return 0;
+ }
+ if (r < 0)
+ return r;
+
+ /* Ignore the header line */
+ (void) read_line(f, (size_t) -1, NULL);
+
+ for (;;) {
+ char *controller;
+ int enabled = 0;
+
+ errno = 0;
+ if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
+
+ if (feof(f))
+ break;
+
+ if (ferror(f))
+ return errno_or_else(EIO);
+
+ return -EBADMSG;
+ }
+
+ if (!enabled) {
+ free(controller);
+ continue;
+ }
+
+ if (!cg_controller_is_valid(controller)) {
+ free(controller);
+ return -EBADMSG;
+ }
+
+ r = set_consume(controllers, controller);
+ if (r < 0)
+ return r;
+ }
+
+ *ret = TAKE_PTR(controllers);
+
+ return 0;
+}
+
+/* The hybrid mode was initially implemented in v232 and simply mounted cgroup2 on
+ * /sys/fs/cgroup/systemd. This unfortunately broke other tools (such as docker) which expected the v1
+ * "name=systemd" hierarchy on /sys/fs/cgroup/systemd. From v233 and on, the hybrid mode mounts v2 on
+ * /sys/fs/cgroup/unified and maintains "name=systemd" hierarchy on /sys/fs/cgroup/systemd for compatibility
+ * with other tools.
+ *
+ * To keep live upgrade working, we detect and support v232 layout. When v232 layout is detected, to keep
+ * cgroup v2 process management but disable the compat dual layout, we return true on
+ * cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER) and false on cg_hybrid_unified().
+ */
+static thread_local bool unified_systemd_v232;
+
+int cg_unified_cached(bool flush) {
+ static thread_local CGroupUnified unified_cache = CGROUP_UNIFIED_UNKNOWN;
+
+ struct statfs fs;
+
+ /* Checks if we support the unified hierarchy. Returns an
+ * error when the cgroup hierarchies aren't mounted yet or we
+ * have any other trouble determining if the unified hierarchy
+ * is supported. */
+
+ if (flush)
+ unified_cache = CGROUP_UNIFIED_UNKNOWN;
+ else if (unified_cache >= CGROUP_UNIFIED_NONE)
+ return unified_cache;
+
+ if (statfs("/sys/fs/cgroup/", &fs) < 0)
+ return log_debug_errno(errno, "statfs(\"/sys/fs/cgroup/\") failed: %m");
+
+ if (F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
+ log_debug("Found cgroup2 on /sys/fs/cgroup/, full unified hierarchy");
+ unified_cache = CGROUP_UNIFIED_ALL;
+ } else if (F_TYPE_EQUAL(fs.f_type, TMPFS_MAGIC)) {
+ if (statfs("/sys/fs/cgroup/unified/", &fs) == 0 &&
+ F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
+ log_debug("Found cgroup2 on /sys/fs/cgroup/unified, unified hierarchy for systemd controller");
+ unified_cache = CGROUP_UNIFIED_SYSTEMD;
+ unified_systemd_v232 = false;
+ } else {
+ if (statfs("/sys/fs/cgroup/systemd/", &fs) < 0)
+ return log_debug_errno(errno, "statfs(\"/sys/fs/cgroup/systemd\" failed: %m");
+
+ if (F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
+ log_debug("Found cgroup2 on /sys/fs/cgroup/systemd, unified hierarchy for systemd controller (v232 variant)");
+ unified_cache = CGROUP_UNIFIED_SYSTEMD;
+ unified_systemd_v232 = true;
+ } else if (F_TYPE_EQUAL(fs.f_type, CGROUP_SUPER_MAGIC)) {
+ log_debug("Found cgroup on /sys/fs/cgroup/systemd, legacy hierarchy");
+ unified_cache = CGROUP_UNIFIED_NONE;
+ } else {
+ log_debug("Unexpected filesystem type %llx mounted on /sys/fs/cgroup/systemd, assuming legacy hierarchy",
+ (unsigned long long) fs.f_type);
+ unified_cache = CGROUP_UNIFIED_NONE;
+ }
+ }
+ } else if (F_TYPE_EQUAL(fs.f_type, SYSFS_MAGIC)) {
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
+ "No filesystem is currently mounted on /sys/fs/cgroup.");
+ } else
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
+ "Unknown filesystem type %llx mounted on /sys/fs/cgroup.",
+ (unsigned long long)fs.f_type);
+
+ return unified_cache;
+}
+
+int cg_unified_controller(const char *controller) {
+ int r;
+
+ r = cg_unified_cached(false);
+ if (r < 0)
+ return r;
+
+ if (r == CGROUP_UNIFIED_NONE)
+ return false;
+
+ if (r >= CGROUP_UNIFIED_ALL)
+ return true;
+
+ return streq_ptr(controller, SYSTEMD_CGROUP_CONTROLLER);
+}
+
+int cg_all_unified(void) {
+ int r;
+
+ r = cg_unified_cached(false);
+ if (r < 0)
+ return r;
+
+ return r >= CGROUP_UNIFIED_ALL;
+}
+
+int cg_hybrid_unified(void) {
+ int r;
+
+ r = cg_unified_cached(false);
+ if (r < 0)
+ return r;
+
+ return r == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232;
+}
+
+const uint64_t cgroup_io_limit_defaults[_CGROUP_IO_LIMIT_TYPE_MAX] = {
+ [CGROUP_IO_RBPS_MAX] = CGROUP_LIMIT_MAX,
+ [CGROUP_IO_WBPS_MAX] = CGROUP_LIMIT_MAX,
+ [CGROUP_IO_RIOPS_MAX] = CGROUP_LIMIT_MAX,
+ [CGROUP_IO_WIOPS_MAX] = CGROUP_LIMIT_MAX,
+};
+
+static const char* const cgroup_io_limit_type_table[_CGROUP_IO_LIMIT_TYPE_MAX] = {
+ [CGROUP_IO_RBPS_MAX] = "IOReadBandwidthMax",
+ [CGROUP_IO_WBPS_MAX] = "IOWriteBandwidthMax",
+ [CGROUP_IO_RIOPS_MAX] = "IOReadIOPSMax",
+ [CGROUP_IO_WIOPS_MAX] = "IOWriteIOPSMax",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(cgroup_io_limit_type, CGroupIOLimitType);
+
+bool is_cgroup_fs(const struct statfs *s) {
+ return is_fs_type(s, CGROUP_SUPER_MAGIC) ||
+ is_fs_type(s, CGROUP2_SUPER_MAGIC);
+}
+
+bool fd_is_cgroup_fs(int fd) {
+ struct statfs s;
+
+ if (fstatfs(fd, &s) < 0)
+ return -errno;
+
+ return is_cgroup_fs(&s);
+}
+
+static const char *const cgroup_controller_table[_CGROUP_CONTROLLER_MAX] = {
+ [CGROUP_CONTROLLER_CPU] = "cpu",
+ [CGROUP_CONTROLLER_CPUACCT] = "cpuacct",
+ [CGROUP_CONTROLLER_CPUSET] = "cpuset",
+ [CGROUP_CONTROLLER_IO] = "io",
+ [CGROUP_CONTROLLER_BLKIO] = "blkio",
+ [CGROUP_CONTROLLER_MEMORY] = "memory",
+ [CGROUP_CONTROLLER_DEVICES] = "devices",
+ [CGROUP_CONTROLLER_PIDS] = "pids",
+ [CGROUP_CONTROLLER_BPF_FIREWALL] = "bpf-firewall",
+ [CGROUP_CONTROLLER_BPF_DEVICES] = "bpf-devices",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(cgroup_controller, CGroupController);
+
+CGroupMask get_cpu_accounting_mask(void) {
+ static CGroupMask needed_mask = (CGroupMask) -1;
+
+ /* On kernel ≥4.15 with unified hierarchy, cpu.stat's usage_usec is
+ * provided externally from the CPU controller, which means we don't
+ * need to enable the CPU controller just to get metrics. This is good,
+ * because enabling the CPU controller comes at a minor performance
+ * hit, especially when it's propagated deep into large hierarchies.
+ * There's also no separate CPU accounting controller available within
+ * a unified hierarchy.
+ *
+ * This combination of factors results in the desired cgroup mask to
+ * enable for CPU accounting varying as follows:
+ *
+ * ╔═════════════════════╤═════════════════════╗
+ * ║ Linux ≥4.15 │ Linux <4.15 ║
+ * ╔═══════════════╬═════════════════════╪═════════════════════╣
+ * ║ Unified ║ nothing │ CGROUP_MASK_CPU ║
+ * ╟───────────────╫─────────────────────┼─────────────────────╢
+ * ║ Hybrid/Legacy ║ CGROUP_MASK_CPUACCT │ CGROUP_MASK_CPUACCT ║
+ * ╚═══════════════╩═════════════════════╧═════════════════════╝
+ *
+ * We check kernel version here instead of manually checking whether
+ * cpu.stat is present for every cgroup, as that check in itself would
+ * already be fairly expensive.
+ *
+ * Kernels where this patch has been backported will therefore have the
+ * CPU controller enabled unnecessarily. This is more expensive than
+ * necessary, but harmless. ☺️
+ */
+
+ if (needed_mask == (CGroupMask) -1) {
+ if (cg_all_unified()) {
+ struct utsname u;
+ assert_se(uname(&u) >= 0);
+
+ if (str_verscmp(u.release, "4.15") < 0)
+ needed_mask = CGROUP_MASK_CPU;
+ else
+ needed_mask = 0;
+ } else
+ needed_mask = CGROUP_MASK_CPUACCT;
+ }
+
+ return needed_mask;
+}
+
+bool cpu_accounting_is_cheap(void) {
+ return get_cpu_accounting_mask() == 0;
+}
+
+static const char* const managed_oom_mode_table[_MANAGED_OOM_MODE_MAX] = {
+ [MANAGED_OOM_AUTO] = "auto",
+ [MANAGED_OOM_KILL] = "kill",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(managed_oom_mode, ManagedOOMMode);
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-29 08:15:01 +0000