From 19f4f86bfed21c5326ed2acebe1163f3a83e832b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 04:25:50 +0200 Subject: Adding upstream version 241. Signed-off-by: Daniel Baumann --- src/basic/cgroup-util.c | 2933 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2933 insertions(+) create mode 100644 src/basic/cgroup-util.c (limited to 'src/basic/cgroup-util.c') diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c new file mode 100644 index 0000000..8ce7ccb --- /dev/null +++ b/src/basic/cgroup-util.c @@ -0,0 +1,2933 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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.h" +#include "mkdir.h" +#include "parse-util.h" +#include "path-util.h" +#include "proc-cmdline.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" + +int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) { + _cleanup_free_ char *fs = NULL; + FILE *f; + int r; + + assert(_f); + + r = cg_get_path(controller, path, "cgroup.procs", &fs); + if (r < 0) + return r; + + f = fopen(fs, "re"); + if (!f) + return -errno; + + *_f = f; + return 0; +} + +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 > 0 ? -errno : -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 **val) { + + _cleanup_free_ char *events = NULL, *content = NULL; + char *p, *line; + 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; + + p = content; + while ((line = strsep(&p, "\n"))) { + char *key; + + key = strsep(&line, " "); + if (!key || !line) + return -EINVAL; + + if (strcmp(key, event)) + continue; + + *val = strdup(line); + return 0; + } + + return -ENOENT; +} + +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; +} + +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; +} + +int cg_kill( + 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; + bool done = false; + int r, ret = 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_processes(controller, path, &f); + 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) + 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) + 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_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 = strjoin(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; +} + +int cg_migrate( + const char *cfrom, + const char *pfrom, + const char *cto, + const char *pto, + CGroupFlags flags) { + + bool done = false; + _cleanup_set_free_ Set *s = NULL; + int r, ret = 0; + pid_t my_pid; + + assert(cfrom); + assert(pfrom); + assert(cto); + assert(pto); + + s = 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_processes(cfrom, pfrom, &f); + if (r < 0) { + if (ret >= 0 && r != -ENOENT) + return r; + + return ret; + } + + while ((r = cg_read_pid(f, &pid)) > 0) { + + /* This might do weird stuff if we aren't a + * single-threaded program. However, we + * luckily know we are not */ + if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid) + continue; + + if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid)) + continue; + + /* Ignore kernel threads. Since they can only + * exist in the root cgroup, we only check for + * them there. */ + if (cfrom && + empty_or_root(pfrom) && + is_kernel_thread(pid) > 0) + continue; + + r = cg_attach(cto, pto, pid); + if (r < 0) { + if (ret >= 0 && r != -ESRCH) + ret = r; + } else if (ret == 0) + 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; + } + } while (!done); + + return ret; +} + +int cg_migrate_recursive( + const char *cfrom, + const char *pfrom, + const char *cto, + const char *pto, + CGroupFlags flags) { + + _cleanup_closedir_ DIR *d = NULL; + int r, ret = 0; + char *fn; + + assert(cfrom); + assert(pfrom); + assert(cto); + assert(pto); + + ret = cg_migrate(cfrom, pfrom, cto, pto, flags); + + r = cg_enumerate_subgroups(cfrom, pfrom, &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 = strjoin(pfrom, "/", fn); + free(fn); + if (!p) + return -ENOMEM; + + r = cg_migrate_recursive(cfrom, p, cto, pto, flags); + if (r != 0 && ret >= 0) + ret = r; + } + + if (r < 0 && ret >= 0) + ret = r; + + if (flags & CGROUP_REMOVE) { + r = cg_rmdir(cfrom, pfrom); + if (r < 0 && ret >= 0 && !IN_SET(r, -ENOENT, -EBUSY)) + return r; + } + + return ret; +} + +int cg_migrate_recursive_fallback( + const char *cfrom, + const char *pfrom, + const char *cto, + const char *pto, + CGroupFlags flags) { + + int r; + + assert(cfrom); + assert(pfrom); + assert(cto); + assert(pto); + + r = cg_migrate_recursive(cfrom, pfrom, cto, pto, flags); + if (r < 0) { + char prefix[strlen(pto) + 1]; + + /* This didn't work? Then let's try all prefixes of the destination */ + + PATH_FOREACH_PREFIX(prefix, pto) { + int q; + + q = cg_migrate_recursive(cfrom, pfrom, cto, prefix, flags); + if (q >= 0) + return q; + } + } + + return r; +} + +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 = strappend("/sys/fs/cgroup/", dn); + else if (isempty(path)) + t = strjoin("/sys/fs/cgroup/", dn, "/", suffix); + else if (isempty(suffix)) + t = strjoin("/sys/fs/cgroup/", dn, "/", path); + else + t = strjoin("/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 = strappend("/sys/fs/cgroup/", suffix); + else if (isempty(suffix)) + t = strappend("/sys/fs/cgroup/", path); + else + t = strjoin("/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 = strjoin(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); +} + +static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) { + assert(path); + assert(sb); + assert(ftwbuf); + + if (typeflag != FTW_DP) + return 0; + + if (ftwbuf->level < 1) + return 0; + + (void) rmdir(path); + return 0; +} + +int cg_trim(const char *controller, const char *path, bool delete_root) { + _cleanup_free_ char *fs = NULL; + int r = 0, q; + + assert(path); + + r = cg_get_path(controller, path, NULL, &fs); + if (r < 0) + return r; + + errno = 0; + if (nftw(fs, trim_cb, 64, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) != 0) { + if (errno == ENOENT) + r = 0; + else if (errno > 0) + r = -errno; + else + r = -EIO; + } + + if (delete_root) { + if (rmdir(fs) < 0 && errno != ENOENT) + return -errno; + } + + q = cg_hybrid_unified(); + if (q < 0) + return q; + if (q > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { + q = cg_trim(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, delete_root); + if (q < 0) + log_warning_errno(q, "Failed to trim compat systemd cgroup %s: %m", path); + } + + return r; +} + +/* Create a cgroup in the hierarchy of controller. + * Returns 0 if the group already existed, 1 on success, negative otherwise. + */ +int cg_create(const char *controller, const char *path) { + _cleanup_free_ char *fs = NULL; + int r; + + r = cg_get_path_and_check(controller, path, NULL, &fs); + if (r < 0) + return r; + + r = mkdir_parents(fs, 0755); + if (r < 0) + return r; + + r = mkdir_errno_wrapper(fs, 0755); + if (r == -EEXIST) + return 0; + if (r < 0) + return r; + + r = cg_hybrid_unified(); + if (r < 0) + return r; + + if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { + r = cg_create(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path); + if (r < 0) + log_warning_errno(r, "Failed to create compat systemd cgroup %s: %m", path); + } + + return 1; +} + +int cg_create_and_attach(const char *controller, const char *path, pid_t pid) { + int r, q; + + assert(pid >= 0); + + r = cg_create(controller, path); + if (r < 0) + return r; + + q = cg_attach(controller, path, pid); + if (q < 0) + return q; + + /* This does not remove the cgroup on failure */ + return r; +} + +int cg_attach(const char *controller, const char *path, pid_t pid) { + _cleanup_free_ char *fs = NULL; + char c[DECIMAL_STR_MAX(pid_t) + 2]; + int r; + + assert(path); + assert(pid >= 0); + + r = cg_get_path_and_check(controller, path, "cgroup.procs", &fs); + if (r < 0) + return r; + + if (pid == 0) + pid = getpid_cached(); + + xsprintf(c, PID_FMT "\n", pid); + + r = write_string_file(fs, c, WRITE_STRING_FILE_DISABLE_BUFFER); + if (r < 0) + return r; + + r = cg_hybrid_unified(); + if (r < 0) + return r; + + if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { + r = cg_attach(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, pid); + if (r < 0) + log_warning_errno(r, "Failed to attach "PID_FMT" to compat systemd cgroup %s: %m", pid, path); + } + + return 0; +} + +int cg_attach_fallback(const char *controller, const char *path, pid_t pid) { + int r; + + assert(controller); + assert(path); + assert(pid >= 0); + + r = cg_attach(controller, path, pid); + if (r < 0) { + char prefix[strlen(path) + 1]; + + /* This didn't work? Then let's try all prefixes of + * the destination */ + + PATH_FOREACH_PREFIX(prefix, path) { + int q; + + q = cg_attach(controller, prefix, pid); + if (q >= 0) + return q; + } + } + + return r; +} + +int cg_set_access( + const char *controller, + const char *path, + uid_t uid, + gid_t gid) { + + struct Attribute { + const char *name; + bool fatal; + }; + + /* cgroup v1, aka legacy/non-unified */ + static const struct Attribute legacy_attributes[] = { + { "cgroup.procs", true }, + { "tasks", false }, + { "cgroup.clone_children", false }, + {}, + }; + + /* cgroup v2, aka unified */ + static const struct Attribute unified_attributes[] = { + { "cgroup.procs", true }, + { "cgroup.subtree_control", true }, + { "cgroup.threads", false }, + {}, + }; + + static const struct Attribute* const attributes[] = { + [false] = legacy_attributes, + [true] = unified_attributes, + }; + + _cleanup_free_ char *fs = NULL; + const struct Attribute *i; + int r, unified; + + assert(path); + + if (uid == UID_INVALID && gid == GID_INVALID) + return 0; + + unified = cg_unified_controller(controller); + if (unified < 0) + return unified; + + /* Configure access to the cgroup itself */ + r = cg_get_path(controller, path, NULL, &fs); + if (r < 0) + return r; + + r = chmod_and_chown(fs, 0755, uid, gid); + if (r < 0) + return r; + + /* Configure access to the cgroup's attributes */ + for (i = attributes[unified]; i->name; i++) { + fs = mfree(fs); + + r = cg_get_path(controller, path, i->name, &fs); + if (r < 0) + return r; + + r = chmod_and_chown(fs, 0644, uid, gid); + if (r < 0) { + if (i->fatal) + return r; + + log_debug_errno(r, "Failed to set access on cgroup %s, ignoring: %m", fs); + } + } + + if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { + r = cg_hybrid_unified(); + if (r < 0) + return r; + if (r > 0) { + /* Always propagate access mode from unified to legacy controller */ + r = cg_set_access(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, uid, gid); + if (r < 0) + log_debug_errno(r, "Failed to set access on compatibility systemd cgroup %s, ignoring: %m", path); + } + } + + return 0; +} + +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_pid_get_path(const char *controller, pid_t pid, char **path) { + _cleanup_fclose_ FILE *f = NULL; + const char *fs, *controller_str; + int unified, r; + size_t cs = 0; + + assert(path); + assert(pid >= 0); + + 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; + + cs = strlen(controller_str); + } + + fs = procfs_file_alloca(pid, "cgroup"); + f = fopen(fs, "re"); + if (!f) + return errno == ENOENT ? -ESRCH : -errno; + + (void) __fsetlocking(f, FSETLOCKING_BYCALLER); + + for (;;) { + _cleanup_free_ char *line = NULL; + char *e, *p; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return r; + if (r == 0) + break; + + if (unified) { + e = startswith(line, "0:"); + if (!e) + continue; + + e = strchr(e, ':'); + if (!e) + continue; + } else { + char *l; + size_t k; + const char *word, *state; + bool found = false; + + l = strchr(line, ':'); + if (!l) + continue; + + l++; + e = strchr(l, ':'); + if (!e) + continue; + + *e = 0; + FOREACH_WORD_SEPARATOR(word, k, l, ",", state) + if (k == cs && memcmp(word, controller_str, cs) == 0) { + found = true; + break; + } + if (!found) + continue; + } + + p = strdup(e + 1); + if (!p) + return -ENOMEM; + + /* Truncate suffix indicating the process is a zombie */ + e = endswith(p, " (deleted)"); + if (e) + *e = 0; + + *path = p; + return 0; + } + + return -ENODATA; +} + +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 = strjoin(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 **controller, char **path) { + char *t = NULL, *u = NULL; + const char *e; + + assert(spec); + + if (*spec == '/') { + if (!path_is_normalized(spec)) + return -EINVAL; + + if (path) { + t = strdup(spec); + if (!t) + return -ENOMEM; + + *path = path_simplify(t, false); + } + + if (controller) + *controller = NULL; + + return 0; + } + + e = strchr(spec, ':'); + if (!e) { + if (!cg_controller_is_valid(spec)) + return -EINVAL; + + if (controller) { + t = strdup(spec); + if (!t) + return -ENOMEM; + + *controller = t; + } + + if (path) + *path = NULL; + + return 0; + } + + t = strndup(spec, e-spec); + if (!t) + return -ENOMEM; + if (!cg_controller_is_valid(t)) { + free(t); + return -EINVAL; + } + + if (isempty(e+1)) + u = NULL; + else { + u = strdup(e+1); + if (!u) { + free(t); + return -ENOMEM; + } + + if (!path_is_normalized(u) || + !path_is_absolute(u)) { + free(t); + free(u); + return -EINVAL; + } + + path_simplify(u, false); + } + + if (controller) + *controller = t; + else + free(t); + + if (path) + *path = u; + else + free(u); + + 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 from here + * on. */ + 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 strappend("_", 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 unitialized: + * 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_keyed_attribute( + const char *controller, + const char *path, + const char *attribute, + char **keys, + char **ret_values) { + + _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. */ + + 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); + } + + r = -ENXIO; + +fail: + for (i = 0; i < n; i++) + free(v[i]); + + return r; + +done: + memcpy(ret_values, v, sizeof(char*) * n); + return 0; + +} + +int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path) { + CGroupController c; + CGroupMask done; + bool created; + int r; + + /* This one will create a cgroup in our private tree, but also + * duplicate it in the trees specified in mask, and remove it + * in all others. + * + * Returns 0 if the group already existed in the systemd hierarchy, + * 1 on success, negative otherwise. + */ + + /* First create the cgroup in our own hierarchy. */ + r = cg_create(SYSTEMD_CGROUP_CONTROLLER, path); + if (r < 0) + return r; + created = r; + + /* If we are in the unified hierarchy, we are done now */ + r = cg_all_unified(); + if (r < 0) + return r; + if (r > 0) + return created; + + supported &= CGROUP_MASK_V1; + mask = CGROUP_MASK_EXTEND_JOINED(mask); + done = 0; + + /* Otherwise, do the same in the other hierarchies */ + for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) { + CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c); + const char *n; + + if (!FLAGS_SET(supported, bit)) + continue; + + if (FLAGS_SET(done, bit)) + continue; + + n = cgroup_controller_to_string(c); + if (FLAGS_SET(mask, bit)) + (void) cg_create(n, path); + else + (void) cg_trim(n, path, true); + + done |= CGROUP_MASK_EXTEND_JOINED(bit); + } + + return created; +} + +int cg_attach_everywhere(CGroupMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) { + CGroupController c; + CGroupMask done; + int r; + + r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, path, pid); + if (r < 0) + return r; + + r = cg_all_unified(); + if (r < 0) + return r; + if (r > 0) + return 0; + + supported &= CGROUP_MASK_V1; + done = 0; + + for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) { + CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c); + const char *p = NULL; + + if (!FLAGS_SET(supported, bit)) + continue; + + if (FLAGS_SET(done, bit)) + continue; + + if (path_callback) + p = path_callback(bit, userdata); + if (!p) + p = path; + + (void) cg_attach_fallback(cgroup_controller_to_string(c), p, pid); + done |= CGROUP_MASK_EXTEND_JOINED(bit); + } + + return 0; +} + +int cg_attach_many_everywhere(CGroupMask supported, const char *path, Set* pids, cg_migrate_callback_t path_callback, void *userdata) { + Iterator i; + void *pidp; + int r = 0; + + SET_FOREACH(pidp, pids, i) { + pid_t pid = PTR_TO_PID(pidp); + int q; + + q = cg_attach_everywhere(supported, path, pid, path_callback, userdata); + if (q < 0 && r >= 0) + r = q; + } + + return r; +} + +int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) { + CGroupController c; + CGroupMask done; + int r = 0, q; + + if (!path_equal(from, to)) { + r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, CGROUP_REMOVE); + if (r < 0) + return r; + } + + q = cg_all_unified(); + if (q < 0) + return q; + if (q > 0) + return r; + + supported &= CGROUP_MASK_V1; + done = 0; + + for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) { + CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c); + const char *p = NULL; + + if (!FLAGS_SET(supported, bit)) + continue; + + if (FLAGS_SET(done, bit)) + continue; + + if (to_callback) + p = to_callback(bit, userdata); + if (!p) + p = to; + + (void) cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, cgroup_controller_to_string(c), p, 0); + done |= CGROUP_MASK_EXTEND_JOINED(bit); + } + + return r; +} + +int cg_trim_everywhere(CGroupMask supported, const char *path, bool delete_root) { + CGroupController c; + CGroupMask done; + int r, q; + + r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root); + if (r < 0) + return r; + + q = cg_all_unified(); + if (q < 0) + return q; + if (q > 0) + return r; + + supported &= CGROUP_MASK_V1; + done = 0; + + for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) { + CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c); + + if (!FLAGS_SET(supported, bit)) + continue; + + if (FLAGS_SET(done, bit)) + continue; + + (void) cg_trim(cgroup_controller_to_string(c), path, delete_root); + done |= CGROUP_MASK_EXTEND_JOINED(bit); + } + + return r; +} + +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 a 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; + + /* Currently, we support the cpu, memory, io and pids controller in the unified hierarchy, mask + * everything else off. */ + 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; + + f = fopen("/proc/cgroups", "re"); + if (!f) { + if (errno == ENOENT) { + *ret = NULL; + return 0; + } + + return -errno; + } + + (void) __fsetlocking(f, FSETLOCKING_BYCALLER); + + /* 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) && errno > 0) + return -errno; + + 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; +} + +static thread_local CGroupUnified unified_cache = CGROUP_UNIFIED_UNKNOWN; + +/* 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 mountnbs 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; + +static int cg_unified_update(void) { + + 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 (unified_cache >= CGROUP_UNIFIED_NONE) + return 0; + + 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 + return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM), + "Unknown filesystem type %llx mounted on /sys/fs/cgroup.", + (unsigned long long)fs.f_type); + + return 0; +} + +int cg_unified_controller(const char *controller) { + int r; + + r = cg_unified_update(); + if (r < 0) + return r; + + if (unified_cache == CGROUP_UNIFIED_NONE) + return false; + + if (unified_cache >= CGROUP_UNIFIED_ALL) + return true; + + return streq_ptr(controller, SYSTEMD_CGROUP_CONTROLLER); +} + +int cg_all_unified(void) { + int r; + + r = cg_unified_update(); + if (r < 0) + return r; + + return unified_cache >= CGROUP_UNIFIED_ALL; +} + +int cg_hybrid_unified(void) { + int r; + + r = cg_unified_update(); + if (r < 0) + return r; + + return unified_cache == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232; +} + +int cg_unified_flush(void) { + unified_cache = CGROUP_UNIFIED_UNKNOWN; + + return cg_unified_update(); +} + +int cg_enable_everywhere( + CGroupMask supported, + CGroupMask mask, + const char *p, + CGroupMask *ret_result_mask) { + + _cleanup_fclose_ FILE *f = NULL; + _cleanup_free_ char *fs = NULL; + CGroupController c; + CGroupMask ret = 0; + int r; + + assert(p); + + if (supported == 0) { + if (ret_result_mask) + *ret_result_mask = 0; + return 0; + } + + r = cg_all_unified(); + if (r < 0) + return r; + if (r == 0) { + /* On the legacy hiearchy there's no concept of "enabling" controllers in cgroups defined. Let's claim + * complete success right away. (If you wonder why we return the full mask here, rather than zero: the + * caller tends to use the returned mask later on to compare if all controllers where properly joined, + * and if not requeues realization. This use is the primary purpose of the return value, hence let's + * minimize surprises here and reduce triggers for re-realization by always saying we fully + * succeeded.) */ + if (ret_result_mask) + *ret_result_mask = mask & supported & CGROUP_MASK_V2; /* If you wonder why we mask this with + * CGROUP_MASK_V2: The 'supported' mask + * might contain pure-V1 or BPF + * controllers, and we never want to + * claim that we could enable those with + * cgroup.subtree_control */ + return 0; + } + + r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, p, "cgroup.subtree_control", &fs); + if (r < 0) + return r; + + for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) { + CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c); + const char *n; + + if (!FLAGS_SET(CGROUP_MASK_V2, bit)) + continue; + + if (!FLAGS_SET(supported, bit)) + continue; + + n = cgroup_controller_to_string(c); + { + char s[1 + strlen(n) + 1]; + + s[0] = FLAGS_SET(mask, bit) ? '+' : '-'; + strcpy(s + 1, n); + + if (!f) { + f = fopen(fs, "we"); + if (!f) + return log_debug_errno(errno, "Failed to open cgroup.subtree_control file of %s: %m", p); + } + + r = write_string_stream(f, s, WRITE_STRING_FILE_DISABLE_BUFFER); + if (r < 0) { + log_debug_errno(r, "Failed to %s controller %s for %s (%s): %m", + FLAGS_SET(mask, bit) ? "enable" : "disable", n, p, fs); + clearerr(f); + + /* If we can't turn off a controller, leave it on in the reported resulting mask. This + * happens for example when we attempt to turn off a controller up in the tree that is + * used down in the tree. */ + if (!FLAGS_SET(mask, bit) && r == -EBUSY) /* You might wonder why we check for EBUSY + * only here, and not follow the same logic + * for other errors such as EINVAL or + * EOPNOTSUPP or anything else. That's + * because EBUSY indicates that the + * controllers is currently enabled and + * cannot be disabled because something down + * the hierarchy is still using it. Any other + * error most likely means something like "I + * never heard of this controller" or + * similar. In the former case it's hence + * safe to assume the controller is still on + * after the failed operation, while in the + * latter case it's safer to assume the + * controller is unknown and hence certainly + * not enabled. */ + ret |= bit; + } else { + /* Otherwise, if we managed to turn on a controller, set the bit reflecting that. */ + if (FLAGS_SET(mask, bit)) + ret |= bit; + } + } + } + + /* Let's return the precise set of controllers now enabled for the cgroup. */ + if (ret_result_mask) + *ret_result_mask = ret; + + return 0; +} + +bool cg_is_unified_wanted(void) { + static thread_local int wanted = -1; + int r; + bool b; + const bool is_default = DEFAULT_HIERARCHY == CGROUP_UNIFIED_ALL; + _cleanup_free_ char *c = NULL; + + /* If we have a cached value, return that. */ + if (wanted >= 0) + return wanted; + + /* If the hierarchy is already mounted, then follow whatever + * was chosen for it. */ + if (cg_unified_flush() >= 0) + return (wanted = unified_cache >= CGROUP_UNIFIED_ALL); + + /* If we were explicitly passed systemd.unified_cgroup_hierarchy, + * respect that. */ + r = proc_cmdline_get_bool("systemd.unified_cgroup_hierarchy", &b); + if (r > 0) + return (wanted = b); + + /* If we passed cgroup_no_v1=all with no other instructions, it seems + * highly unlikely that we want to use hybrid or legacy hierarchy. */ + r = proc_cmdline_get_key("cgroup_no_v1", 0, &c); + if (r > 0 && streq_ptr(c, "all")) + return (wanted = true); + + return (wanted = is_default); +} + +bool cg_is_legacy_wanted(void) { + static thread_local int wanted = -1; + + /* If we have a cached value, return that. */ + if (wanted >= 0) + return wanted; + + /* Check if we have cgroup v2 already mounted. */ + if (cg_unified_flush() >= 0 && + unified_cache == CGROUP_UNIFIED_ALL) + return (wanted = false); + + /* Otherwise, assume that at least partial legacy is wanted, + * since cgroup v2 should already be mounted at this point. */ + return (wanted = true); +} + +bool cg_is_hybrid_wanted(void) { + static thread_local int wanted = -1; + int r; + bool b; + const bool is_default = DEFAULT_HIERARCHY >= CGROUP_UNIFIED_SYSTEMD; + /* We default to true if the default is "hybrid", obviously, + * but also when the default is "unified", because if we get + * called, it means that unified hierarchy was not mounted. */ + + /* If we have a cached value, return that. */ + if (wanted >= 0) + return wanted; + + /* If the hierarchy is already mounted, then follow whatever + * was chosen for it. */ + if (cg_unified_flush() >= 0 && + unified_cache == CGROUP_UNIFIED_ALL) + return (wanted = false); + + /* Otherwise, let's see what the kernel command line has to say. + * Since checking is expensive, cache a non-error result. */ + r = proc_cmdline_get_bool("systemd.legacy_systemd_cgroup_controller", &b); + + /* The meaning of the kernel option is reversed wrt. to the return value + * of this function, hence the negation. */ + return (wanted = r > 0 ? !b : is_default); +} + +int cg_weight_parse(const char *s, uint64_t *ret) { + uint64_t u; + int r; + + if (isempty(s)) { + *ret = CGROUP_WEIGHT_INVALID; + return 0; + } + + r = safe_atou64(s, &u); + if (r < 0) + return r; + + if (u < CGROUP_WEIGHT_MIN || u > CGROUP_WEIGHT_MAX) + return -ERANGE; + + *ret = u; + return 0; +} + +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); + +int cg_cpu_shares_parse(const char *s, uint64_t *ret) { + uint64_t u; + int r; + + if (isempty(s)) { + *ret = CGROUP_CPU_SHARES_INVALID; + return 0; + } + + r = safe_atou64(s, &u); + if (r < 0) + return r; + + if (u < CGROUP_CPU_SHARES_MIN || u > CGROUP_CPU_SHARES_MAX) + return -ERANGE; + + *ret = u; + return 0; +} + +int cg_blkio_weight_parse(const char *s, uint64_t *ret) { + uint64_t u; + int r; + + if (isempty(s)) { + *ret = CGROUP_BLKIO_WEIGHT_INVALID; + return 0; + } + + r = safe_atou64(s, &u); + if (r < 0) + return r; + + if (u < CGROUP_BLKIO_WEIGHT_MIN || u > CGROUP_BLKIO_WEIGHT_MAX) + return -ERANGE; + + *ret = u; + return 0; +} + +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 *cgroup_controller_table[_CGROUP_CONTROLLER_MAX] = { + [CGROUP_CONTROLLER_CPU] = "cpu", + [CGROUP_CONTROLLER_CPUACCT] = "cpuacct", + [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; +} -- cgit v1.2.3