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Systemd/src/basic/cgroup-util.c

2189 lines
61 KiB

/* 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);