cgroup-util.c revision 8b0849e9710d721c5d0b775aaf0fd662eefa1449
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <ftw.h>
#include "cgroup-util.h"
#include "set.h"
#include "macro.h"
#include "util.h"
#include "formats-util.h"
#include "process-util.h"
#include "path-util.h"
#include "unit-name.h"
#include "fileio.h"
#include "special.h"
#include "mkdir.h"
#include "login-shared.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 ? -errno : -EIO;
}
if (ul <= 0)
return -EIO;
*_pid = (pid_t) ul;
return 1;
}
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(de, d, return -errno) {
char *b;
if (de->d_type != DT_DIR)
continue;
if (streq(de->d_name, ".") ||
streq(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;
return 0;
}
int cg_kill(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, Set *s) {
_cleanup_set_free_ Set *allocated_set = NULL;
bool done = false;
int r, ret = 0;
pid_t my_pid;
assert(sig >= 0);
/* 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();
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 (ignore_self && pid == my_pid)
continue;
if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid))
continue;
/* If we haven't killed this process yet, kill
* it */
if (kill(pid, sig) < 0) {
if (ret >= 0 && errno != ESRCH)
ret = -errno;
} else {
if (sigcont && sig != SIGKILL)
kill(pid, SIGCONT);
if (ret == 0)
ret = 1;
}
done = false;
r = set_put(s, LONG_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, bool sigcont, bool ignore_self, bool rem, Set *s) {
_cleanup_set_free_ Set *allocated_set = NULL;
_cleanup_closedir_ DIR *d = NULL;
int r, ret = 0;
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, sigcont, ignore_self, s);
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, NULL);
free(fn);
if (!p)
return -ENOMEM;
r = cg_kill_recursive(controller, p, sig, sigcont, ignore_self, rem, s);
if (ret >= 0 && r != 0)
ret = r;
}
if (ret >= 0 && r < 0)
ret = r;
if (rem) {
r = cg_rmdir(controller, path);
if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
return r;
}
return ret;
}
int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self) {
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();
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 (ignore_self && pid == my_pid)
continue;
if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid))
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, LONG_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,
bool ignore_self,
bool rem) {
_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, ignore_self);
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, NULL);
free(fn);
if (!p) {
if (ret >= 0)
return -ENOMEM;
return ret;
}
r = cg_migrate_recursive(cfrom, p, cto, pto, ignore_self, rem);
if (r != 0 && ret >= 0)
ret = r;
}
if (r < 0 && ret >= 0)
ret = r;
if (rem) {
r = cg_rmdir(cfrom, pfrom);
if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
return r;
}
return ret;
}
int cg_migrate_recursive_fallback(
const char *cfrom,
const char *pfrom,
const char *cto,
const char *pto,
bool ignore_self,
bool rem) {
int r;
assert(cfrom);
assert(pfrom);
assert(cto);
assert(pto);
r = cg_migrate_recursive(cfrom, pfrom, cto, pto, ignore_self, rem);
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) {
r = cg_migrate_recursive(cfrom, pfrom, cto, prefix, ignore_self, rem);
if (r >= 0)
break;
}
}
return 0;
}
static const char *normalize_controller(const char *controller) {
assert(controller);
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
return "systemd";
else if (startswith(controller, "name="))
return controller + 5;
else
return controller;
}
static int join_path(const char *controller, const char *path, const char *suffix, char **fs) {
char *t = NULL;
if (!isempty(controller)) {
if (!isempty(path) && !isempty(suffix))
t = strjoin("/sys/fs/cgroup/", controller, "/", path, "/", suffix, NULL);
else if (!isempty(path))
t = strjoin("/sys/fs/cgroup/", controller, "/", path, NULL);
else if (!isempty(suffix))
t = strjoin("/sys/fs/cgroup/", controller, "/", suffix, NULL);
else
t = strappend("/sys/fs/cgroup/", controller);
} else {
if (!isempty(path) && !isempty(suffix))
t = strjoin(path, "/", suffix, NULL);
else if (!isempty(path))
t = strdup(path);
else
return -EINVAL;
}
if (!t)
return -ENOMEM;
*fs = path_kill_slashes(t);
return 0;
}
int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
const char *p;
static thread_local bool good = false;
assert(fs);
if (controller && !cg_controller_is_valid(controller, true))
return -EINVAL;
if (_unlikely_(!good)) {
int r;
r = path_is_mount_point("/sys/fs/cgroup", false);
if (r < 0)
return r;
if (r == 0)
return -ENOENT;
/* Cache this to save a few stat()s */
good = true;
}
p = controller ? normalize_controller(controller) : NULL;
return join_path(p, path, suffix, fs);
}
static int check_hierarchy(const char *p) {
const char *cc;
assert(p);
if (!filename_is_valid(p))
return 0;
/* Check if this controller actually really exists */
cc = strjoina("/sys/fs/cgroup/", p);
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) {
const char *p;
int r;
assert(fs);
if (!cg_controller_is_valid(controller, true))
return -EINVAL;
/* Normalize the controller syntax */
p = normalize_controller(controller);
/* Check if this controller actually really exists */
r = check_hierarchy(p);
if (r < 0)
return r;
return join_path(p, 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;
rmdir(path);
return 0;
}
int cg_trim(const char *controller, const char *path, bool delete_root) {
_cleanup_free_ char *fs = NULL;
int r = 0;
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)
r = errno ? -errno : -EIO;
if (delete_root) {
if (rmdir(fs) < 0 && errno != ENOENT)
return -errno;
}
return r;
}
int cg_delete(const char *controller, const char *path) {
_cleanup_free_ char *parent = NULL;
int r;
assert(path);
r = path_get_parent(path, &parent);
if (r < 0)
return r;
r = cg_migrate_recursive(controller, path, controller, parent, false, true);
return r == -ENOENT ? 0 : r;
}
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;
if (mkdir(fs, 0755) < 0) {
if (errno == EEXIST)
return 0;
return -errno;
}
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();
snprintf(c, sizeof(c), PID_FMT"\n", pid);
return write_string_file_no_create(fs, c);
}
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) {
r = cg_attach(controller, prefix, pid);
if (r >= 0)
break;
}
}
return 0;
}
int cg_set_group_access(
const char *controller,
const char *path,
mode_t mode,
uid_t uid,
gid_t gid) {
_cleanup_free_ char *fs = NULL;
int r;
assert(path);
if (mode != MODE_INVALID)
mode &= 0777;
r = cg_get_path(controller, path, NULL, &fs);
if (r < 0)
return r;
return chmod_and_chown(fs, mode, uid, gid);
}
int cg_set_task_access(
const char *controller,
const char *path,
mode_t mode,
uid_t uid,
gid_t gid) {
_cleanup_free_ char *fs = NULL, *procs = NULL;
int r;
assert(path);
if (mode == MODE_INVALID && uid == UID_INVALID && gid == GID_INVALID)
return 0;
if (mode != MODE_INVALID)
mode &= 0666;
r = cg_get_path(controller, path, "cgroup.procs", &fs);
if (r < 0)
return r;
r = chmod_and_chown(fs, mode, uid, gid);
if (r < 0)
return r;
/* Compatibility, Always keep values for "tasks" in sync with
* "cgroup.procs" */
r = cg_get_path(controller, path, "tasks", &procs);
if (r < 0)
return r;
return chmod_and_chown(procs, mode, uid, gid);
}
int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
const char *fs;
size_t cs;
assert(path);
assert(pid >= 0);
if (controller) {
if (!cg_controller_is_valid(controller, true))
return -EINVAL;
controller = normalize_controller(controller);
} else
controller = SYSTEMD_CGROUP_CONTROLLER;
fs = procfs_file_alloca(pid, "cgroup");
f = fopen(fs, "re");
if (!f)
return errno == ENOENT ? -ESRCH : -errno;
cs = strlen(controller);
FOREACH_LINE(line, f, return -errno) {
char *l, *p, *e;
size_t k;
const char *word, *state;
bool found = false;
truncate_nl(line);
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, cs) == 0) {
found = true;
break;
}
if (k == 5 + cs &&
memcmp(word, "name=", 5) == 0 &&
memcmp(word+5, controller, cs) == 0) {
found = true;
break;
}
}
if (!found)
continue;
p = strdup(e + 1);
if (!p)
return -ENOMEM;
*path = p;
return 0;
}
return -ENOENT;
}
int cg_install_release_agent(const char *controller, const char *agent) {
_cleanup_free_ char *fs = NULL, *contents = NULL;
char *sc;
int r;
assert(agent);
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 (sc[0] == 0) {
r = write_string_file_no_create(fs, agent);
if (r < 0)
return r;
} else if (!streq(sc, agent))
return -EEXIST;
free(fs);
fs = NULL;
r = cg_get_path(controller, NULL, "notify_on_release", &fs);
if (r < 0)
return r;
free(contents);
contents = NULL;
r = read_one_line_file(fs, &contents);
if (r < 0)
return r;
sc = strstrip(contents);
if (streq(sc, "0")) {
r = write_string_file_no_create(fs, "1");
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_get_path(controller, NULL, "notify_on_release", &fs);
if (r < 0)
return r;
r = write_string_file_no_create(fs, "0");
if (r < 0)
return r;
free(fs);
fs = NULL;
r = cg_get_path(controller, NULL, "release_agent", &fs);
if (r < 0)
return r;
r = write_string_file_no_create(fs, "");
if (r < 0)
return r;
return 0;
}
int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
_cleanup_fclose_ FILE *f = NULL;
pid_t pid = 0, self_pid;
bool found = false;
int r;
assert(path);
r = cg_enumerate_processes(controller, path, &f);
if (r < 0)
return r == -ENOENT ? 1 : r;
self_pid = getpid();
while ((r = cg_read_pid(f, &pid)) > 0) {
if (ignore_self && pid == self_pid)
continue;
found = true;
break;
}
if (r < 0)
return r;
return !found;
}
int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self) {
_cleanup_closedir_ DIR *d = NULL;
char *fn;
int r;
assert(path);
r = cg_is_empty(controller, path, ignore_self);
if (r <= 0)
return r;
r = cg_enumerate_subgroups(controller, path, &d);
if (r < 0)
return r == -ENOENT ? 1 : r;
while ((r = cg_read_subgroup(d, &fn)) > 0) {
_cleanup_free_ char *p = NULL;
p = strjoin(path, "/", fn, NULL);
free(fn);
if (!p)
return -ENOMEM;
r = cg_is_empty_recursive(controller, p, ignore_self);
if (r <= 0)
return r;
}
if (r < 0)
return r;
return 1;
}
int cg_split_spec(const char *spec, char **controller, char **path) {
const char *e;
char *t = NULL, *u = NULL;
_cleanup_free_ char *v = NULL;
assert(spec);
if (*spec == '/') {
if (!path_is_safe(spec))
return -EINVAL;
if (path) {
t = strdup(spec);
if (!t)
return -ENOMEM;
*path = path_kill_slashes(t);
}
if (controller)
*controller = NULL;
return 0;
}
e = strchr(spec, ':');
if (!e) {
if (!cg_controller_is_valid(spec, true))
return -EINVAL;
if (controller) {
t = strdup(normalize_controller(spec));
if (!t)
return -ENOMEM;
*controller = t;
}
if (path)
*path = NULL;
return 0;
}
v = strndup(spec, e-spec);
if (!v)
return -ENOMEM;
t = strdup(normalize_controller(v));
if (!t)
return -ENOMEM;
if (!cg_controller_is_valid(t, true)) {
free(t);
return -EINVAL;
}
if (streq(e+1, "")) {
u = strdup("/");
if (!u) {
free(t);
return -ENOMEM;
}
} else {
u = strdup(e+1);
if (!u) {
free(t);
return -ENOMEM;
}
if (!path_is_safe(u) ||
!path_is_absolute(u)) {
free(t);
free(u);
return -EINVAL;
}
path_kill_slashes(u);
}
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_kill_slashes(t);
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 ? c : SYSTEMD_CGROUP_CONTROLLER, p ? 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_SYSTEM_SLICE);
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)
*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 = raw;
raw = NULL;
} 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, TEMPLATE_INVALID))
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, TEMPLATE_INVALID);
}
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;
}
int cg_path_get_user_unit(const char *path, char **ret) {
const char *e, *t;
char *unit;
int r;
assert(path);
assert(ret);
/* We always have to parse the path from the beginning as unit
* cgroups might have arbitrary child cgroups and we shouldn't get
* confused by those */
/* Skip slices, if there are any */
e = skip_slices(path);
/* Skip the user manager... */
t = skip_user_manager(e);
/* Alternatively skip the user session... */
if (!t)
t = skip_session(e);
if (!t)
return -ENXIO;
/* ... and skip more slices if there are any */
e = skip_slices(t);
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_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, *sl = NULL;
int r;
r = cg_path_get_unit(path, &u);
if (r < 0)
return r;
sl = strjoin("/run/systemd/machines/unit:", u, NULL);
if (!sl)
return -ENOMEM;
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);
for (;;) {
size_t n;
p += strspn(p, "/");
n = strcspn(p, "/");
if (!valid_slice_name(p, n)) {
if (!e) {
char *s;
s = strdup("-.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);
}
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 (p[0] == 0 ||
p[0] == '_' ||
p[0] == '.' ||
streq(p, "notify_on_release") ||
streq(p, "release_agent") ||
streq(p, "tasks"))
need_prefix = true;
else {
const char *dot;
dot = strrchr(p, '.');
if (dot) {
if (dot - p == 6 && memcmp(p, "cgroup", 6) == 0)
need_prefix = true;
else {
char *n;
n = strndupa(p, dot - p);
if (check_hierarchy(n) >= 0)
need_prefix = true;
}
}
}
if (need_prefix)
return strappend("_", p);
else
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, bool allow_named) {
const char *t, *s;
if (!p)
return false;
if (allow_named) {
s = startswith(p, "name=");
if (s)
p = s;
}
if (*p == 0 || *p == '_')
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;
assert(unit);
assert(ret);
if (!unit_name_is_valid(unit, TEMPLATE_INVALID))
return -EINVAL;
if (!endswith(unit, ".slice"))
return -EINVAL;
p = unit_name_to_prefix(unit);
if (!p)
return -ENOMEM;
dash = strchr(p, '-');
while (dash) {
_cleanup_free_ char *escaped = NULL;
char n[dash - p + sizeof(".slice")];
strcpy(stpncpy(n, p, dash - p), ".slice");
if (!unit_name_is_valid(n, TEMPLATE_INVALID))
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 = s;
s = NULL;
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_no_create(p, value);
}
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);
}
static const char mask_names[] =
"cpu\0"
"cpuacct\0"
"blkio\0"
"memory\0"
"devices\0";
int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask mask, const char *path) {
CGroupControllerMask bit = 1;
const char *n;
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 */
/* First create the cgroup in our own hierarchy. */
r = cg_create(SYSTEMD_CGROUP_CONTROLLER, path);
if (r < 0)
return r;
/* Then, do the same in the other hierarchies */
NULSTR_FOREACH(n, mask_names) {
if (mask & bit)
cg_create(n, path);
else if (supported & bit)
cg_trim(n, path, true);
bit <<= 1;
}
return 0;
}
int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) {
CGroupControllerMask bit = 1;
const char *n;
int r;
r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, path, pid);
if (r < 0)
return r;
NULSTR_FOREACH(n, mask_names) {
if (supported & bit) {
const char *p = NULL;
if (path_callback)
p = path_callback(bit, userdata);
if (!p)
p = path;
cg_attach_fallback(n, path, pid);
}
bit <<= 1;
}
return 0;
}
int cg_attach_many_everywhere(CGroupControllerMask 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_LONG(pidp);
int q;
q = cg_attach_everywhere(supported, path, pid, path_callback, userdata);
if (q < 0)
r = q;
}
return r;
}
int cg_migrate_everywhere(CGroupControllerMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) {
CGroupControllerMask bit = 1;
const char *n;
int r;
if (!path_equal(from, to)) {
r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, false, true);
if (r < 0)
return r;
}
NULSTR_FOREACH(n, mask_names) {
if (supported & bit) {
const char *p = NULL;
if (to_callback)
p = to_callback(bit, userdata);
if (!p)
p = to;
cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, n, p, false, false);
}
bit <<= 1;
}
return 0;
}
int cg_trim_everywhere(CGroupControllerMask supported, const char *path, bool delete_root) {
CGroupControllerMask bit = 1;
const char *n;
int r;
r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root);
if (r < 0)
return r;
NULSTR_FOREACH(n, mask_names) {
if (supported & bit)
cg_trim(n, path, delete_root);
bit <<= 1;
}
return 0;
}
CGroupControllerMask cg_mask_supported(void) {
CGroupControllerMask bit = 1, mask = 0;
const char *n;
NULSTR_FOREACH(n, mask_names) {
if (check_hierarchy(n) >= 0)
mask |= bit;
bit <<= 1;
}
return mask;
}
int cg_kernel_controllers(Set *controllers) {
_cleanup_fclose_ FILE *f = NULL;
char buf[LINE_MAX];
int r;
assert(controllers);
f = fopen("/proc/cgroups", "re");
if (!f) {
if (errno == ENOENT)
return 0;
return -errno;
}
/* Ignore the header line */
(void) fgets(buf, sizeof(buf), f);
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)
return -errno;
return -EBADMSG;
}
if (!enabled) {
free(controller);
continue;
}
if (!filename_is_valid(controller)) {
free(controller);
return -EBADMSG;
}
r = set_consume(controllers, controller);
if (r < 0)
return r;
}
return 0;
}