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Systemd/src/basic/cgroup-util.c
Chris Down 5f086dc7db cgroup: Imply systemd.unified_cgroup_hierarchy=1 on cgroup_no_v1=all 
cgroup_no_v1=all doesn't make a whole lot of sense with legacy hierarchy
(where we use v1 hierarchy for everything), or hybrid hierarchy (where
we still use v1 hierarchy for resource control).

Right now we have to tell people to add both cgroup_no_v1=all and
systemd.unified_cgroup_hierarchy=1 to get the desired behaviour,
however in reality it's hard to imagine any situation where someone
passes cgroup_no_v1=all but *doesn't* want to use the unified cgroup
hierarchy.

Make it so that cgroup_no_v1=all produces intuitive behaviour in systemd
by default, although it can still be disabled by passing
systemd.unified_cgroup_hierarchy=0 explicitly.
2018-12-21 13:29:27 +00:00

2934 lines
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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <dirent.h>
#include <errno.h>
#include <ftw.h>
#include <limits.h>
#include <signal.h>
#include <stddef.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/statfs.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.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;
};
/* cgroupsv1, aka legacy/non-unified */
static const struct Attribute legacy_attributes[] = {
{ "cgroup.procs", true },
{ "tasks", false },
{ "cgroup.clone_children", false },
{},
};
/* cgroupsv2, 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 cgroupsv2 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 cgroup v2 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 cgroups2 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 cgroups2 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;
}
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