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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 13:00:47 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 13:00:47 +0000 |
commit | 2cb7e0aaedad73b076ea18c6900b0e86c5760d79 (patch) | |
tree | da68ca54bb79f4080079bf0828acda937593a4e1 /src/basic/cgroup-util.c | |
parent | Initial commit. (diff) | |
download | systemd-2cb7e0aaedad73b076ea18c6900b0e86c5760d79.tar.xz systemd-2cb7e0aaedad73b076ea18c6900b0e86c5760d79.zip |
Adding upstream version 247.3.upstream/247.3upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/cgroup-util.c')
-rw-r--r-- | src/basic/cgroup-util.c | 2189 |
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); |