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Systemd/src/shared/cgroup-util.c
Lennart Poettering 9444b1f20e logind: add infrastructure to keep track of machines, and move to slices 
- This changes all logind cgroup objects to use slice objects rather
  than fixed croup locations.

- logind can now collect minimal information about running
  VMs/containers. As fixed cgroup locations can no longer be used we
  need an entity that keeps track of machine cgroups in whatever slice
  they might be located. Since logind already keeps track of users,
  sessions and seats this is a trivial addition.

- nspawn will now register with logind and pass various bits of metadata
  along. A new option "--slice=" has been added to place the container
  in a specific slice.

- loginctl gained commands to list, introspect and terminate machines.

- user.slice and machine.slice will now be pulled in by logind.service,
  since only logind.service requires this slice.
2013-06-20 03:49:59 +02:00

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/*-*- 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 "log.h"
#include "set.h"
#include "macro.h"
#include "util.h"
#include "path-util.h"
#include "strv.h"
#include "unit-name.h"
#include "fileio.h"
#include "special.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, bool honour_sticky) {
_cleanup_free_ char *p = NULL;
int r;
r = cg_get_path(controller, path, NULL, &p);
if (r < 0)
return r;
if (honour_sticky) {
char *fn;
/* If the sticky bit is set on cgroup.procs, don't
* remove the directory */
fn = strappend(p, "/cgroup.procs");
if (!fn)
return -ENOMEM;
r = file_is_priv_sticky(fn);
free(fn);
if (r > 0)
return 0;
/* Compatibility ... */
fn = strappend(p, "/tasks");
if (!fn)
return -ENOMEM;
r = file_is_priv_sticky(fn);
free(fn);
if (r > 0)
return 0;
}
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(trivial_hash_func, trivial_compare_func);
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 (ret == 0) {
if (sigcont)
kill(pid, SIGCONT);
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(trivial_hash_func, trivial_compare_func);
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, true);
if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
return r;
}
return ret;
}
int cg_kill_recursive_and_wait(const char *controller, const char *path, bool rem) {
unsigned i;
assert(path);
/* This safely kills all processes; first it sends a SIGTERM,
* then checks 8 times after 200ms whether the group is now
* empty, then kills everything that is left with SIGKILL and
* finally checks 5 times after 200ms each whether the group
* is finally empty. */
for (i = 0; i < 15; i++) {
int sig, r;
if (i <= 0)
sig = SIGTERM;
else if (i == 9)
sig = SIGKILL;
else
sig = 0;
r = cg_kill_recursive(controller, path, sig, true, true, rem, NULL);
if (r <= 0)
return r;
usleep(200 * USEC_PER_MSEC);
}
return 0;
}
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(trivial_hash_func, trivial_compare_func);
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, true);
if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
return r;
}
return ret;
}
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;
path_kill_slashes(t);
*fs = t;
return 0;
}
int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
const char *p;
static __thread 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 < 0 ? r : -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) {
char *cc;
assert(p);
/* Check if this controller actually really exists */
cc = alloca(sizeof("/sys/fs/cgroup/") + strlen(p));
strcpy(stpcpy(cc, "/sys/fs/cgroup/"), p);
if (access(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) {
char *p;
bool is_sticky;
if (typeflag != FTW_DP)
return 0;
if (ftwbuf->level < 1)
return 0;
p = strappend(path, "/cgroup.procs");
if (!p) {
errno = ENOMEM;
return 1;
}
is_sticky = file_is_priv_sticky(p) > 0;
free(p);
if (is_sticky)
return 0;
/* Compatibility */
p = strappend(path, "/tasks");
if (!p) {
errno = ENOMEM;
return 1;
}
is_sticky = file_is_priv_sticky(p) > 0;
free(p);
if (is_sticky)
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) {
bool is_sticky;
char *p;
p = strappend(fs, "/cgroup.procs");
if (!p)
return -ENOMEM;
is_sticky = file_is_priv_sticky(p) > 0;
free(p);
if (!is_sticky) {
p = strappend(fs, "/tasks");
if (!p)
return -ENOMEM;
is_sticky = file_is_priv_sticky(p) > 0;
free(p);
}
if (!is_sticky)
if (rmdir(fs) < 0 && errno != ENOENT && r == 0)
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_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), "%lu\n", (unsigned long) pid);
return write_string_file(fs, c);
}
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_t) -1)
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,
int sticky) {
_cleanup_free_ char *fs = NULL, *procs = NULL;
int r;
assert(path);
if (mode == (mode_t) -1 && uid == (uid_t) -1 && gid == (gid_t) -1 && sticky < 0)
return 0;
if (mode != (mode_t) -1)
mode &= 0666;
r = cg_get_path(controller, path, "cgroup.procs", &fs);
if (r < 0)
return r;
if (sticky >= 0 && mode != (mode_t) -1)
/* Both mode and sticky param are passed */
mode |= (sticky ? S_ISVTX : 0);
else if ((sticky >= 0 && mode == (mode_t) -1) ||
(mode != (mode_t) -1 && sticky < 0)) {
struct stat st;
/* Only one param is passed, hence read the current
* mode from the file itself */
r = lstat(fs, &st);
if (r < 0)
return -errno;
if (mode == (mode_t) -1)
/* No mode set, we just shall set the sticky bit */
mode = (st.st_mode & ~S_ISVTX) | (sticky ? S_ISVTX : 0);
else
/* Only mode set, leave sticky bit untouched */
mode = (st.st_mode & ~0777) | mode;
}
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;
if (pid == 0)
fs = "/proc/self/cgroup";
else
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, *w, *e;
size_t k;
char *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(w, k, l, ",", state) {
if (k == cs && memcmp(w, controller, cs) == 0) {
found = true;
break;
}
if (k == 5 + cs &&
memcmp(w, "name=", 5) == 0 &&
memcmp(w+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(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(fs, "1");
if (r < 0)
return r;
return 1;
}
if (!streq(sc, "1"))
return -EIO;
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_by_spec(const char *spec, bool ignore_self) {
_cleanup_free_ char *controller = NULL, *path = NULL;
int r;
assert(spec);
r = cg_split_spec(spec, &controller, &path);
if (r < 0)
return r;
return cg_is_empty(controller, path, ignore_self);
}
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_kill_slashes(t);
*path = 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;
}
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_join_spec(const char *controller, const char *path, char **spec) {
char *s;
assert(path);
if (!controller)
controller = "systemd";
else {
if (!cg_controller_is_valid(controller, true))
return -EINVAL;
controller = normalize_controller(controller);
}
if (!path_is_absolute(path))
return -EINVAL;
s = strjoin(controller, ":", path, NULL);
if (!s)
return -ENOMEM;
path_kill_slashes(s + strlen(controller) + 1);
*spec = s;
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;
path_kill_slashes(t);
*result = 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;
}
char **cg_shorten_controllers(char **controllers) {
char **f, **t;
if (!controllers)
return controllers;
for (f = controllers, t = controllers; *f; f++) {
const char *p;
int r;
p = normalize_controller(*f);
if (streq(p, "systemd")) {
free(*f);
continue;
}
if (!cg_controller_is_valid(p, true)) {
log_warning("Controller %s is not valid, removing from controllers list.", p);
free(*f);
continue;
}
r = check_hierarchy(p);
if (r < 0) {
log_debug("Controller %s is not available, removing from controllers list.", p);
free(*f);
continue;
}
*(t++) = *f;
}
*t = NULL;
return strv_uniq(controllers);
}
int cg_pid_get_path_shifted(pid_t pid, char **root, char **cgroup) {
_cleanup_free_ char *cg_root = NULL;
char *cg_process, *p;
int r;
r = cg_get_root_path(&cg_root);
if (r < 0)
return r;
r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cg_process);
if (r < 0)
return r;
p = path_startswith(cg_process, cg_root);
if (p)
p--;
else
p = cg_process;
if (cgroup) {
char* c;
c = strdup(p);
if (!c) {
free(cg_process);
return -ENOMEM;
}
*cgroup = c;
}
if (root) {
cg_process[p-cg_process] = 0;
*root = cg_process;
} else
free(cg_process);
return 0;
}
int cg_path_decode_unit(const char *cgroup, char **unit){
char *p, *e, *c, *s, *k;
assert(cgroup);
assert(unit);
e = strchrnul(cgroup, '/');
c = strndupa(cgroup, e - cgroup);
c = cg_unescape(c);
/* Could this be a valid unit name? */
if (!unit_name_is_valid(c, true))
return -EINVAL;
if (!unit_name_is_template(c))
s = strdup(c);
else {
if (*e != '/')
return -EINVAL;
e += strspn(e, "/");
p = strchrnul(e, '/');
k = strndupa(e, p - e);
k = cg_unescape(k);
if (!unit_name_is_valid(k, false))
return -EINVAL;
s = strdup(k);
}
if (!s)
return -ENOMEM;
*unit = s;
return 0;
}
static const char *skip_slices(const char *p) {
size_t n;
/* Skips over all slice assignments */
for (;;) {
p += strspn(p, "/");
n = strcspn(p, "/");
if (n <= 6 || memcmp(p + n - 6, ".slice", 6) != 0)
return p;
p += n;
}
}
int cg_path_get_unit(const char *path, char **unit) {
const char *e;
assert(path);
assert(unit);
e = skip_slices(path);
return cg_path_decode_unit(e, unit);
}
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);
}
static const char *skip_user(const char *p) {
size_t n;
assert(p);
p += strspn(p, "/");
n = strcspn(p, "/");
if (n <= 5 || memcmp(p + n - 5, ".user", 5) != 0)
return p;
p += n;
p += strspn(p, "/");
return p;
}
static const char *skip_session(const char *p) {
size_t n;
assert(p);
p += strspn(p, "/");
n = strcspn(p, "/");
if (n <= 8 || memcmp(p + n - 8, ".session", 8) != 0)
return NULL;
p += n;
p += strspn(p, "/");
return p;
}
static const char *skip_systemd_label(const char *p) {
size_t n;
assert(p);
p += strspn(p, "/");
n = strcspn(p, "/");
if (n < 8 || memcmp(p, "systemd-", 8) != 0)
return p;
p += n;
p += strspn(p, "/");
return p;
}
int cg_path_get_user_unit(const char *path, char **unit) {
const char *e;
assert(path);
assert(unit);
/* 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 name, if there is one */
e = skip_user(e);
/* Skip the session ID, require that there is one */
e = skip_session(e);
if (!e)
return -ENOENT;
/* Skip the systemd cgroup, if there is one */
e = skip_systemd_label(e);
return cg_path_decode_unit(e, unit);
}
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) {
const char *e, *n, *x;
char *s, *r;
assert(path);
assert(machine);
/* Skip slices, if there are any */
e = skip_slices(path);
n = strchrnul(e, '/');
if (e == n)
return -ENOENT;
s = strndupa(e, n - e);
s = cg_unescape(s);
x = endswith(s, ".machine");
if (!x)
return -ENOENT;
r = strndup(s, x - s);
if (!r)
return -ENOMEM;
*machine = r;
return 0;
}
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) {
const char *e, *n;
char *s;
assert(path);
assert(session);
/* Skip slices, if there are any */
e = skip_slices(path);
/* Skip the user name, if there is one */
e = skip_user(e);
n = strchrnul(e, '/');
if (n - e < 8)
return -ENOENT;
if (memcmp(n - 8, ".session", 8) != 0)
return -ENOENT;
s = strndup(e, n - e - 8);
if (!s)
return -ENOMEM;
*session = s;
return 0;
}
int cg_pid_get_session(pid_t pid, char **session) {
_cleanup_free_ char *cgroup = NULL;
int r;
assert(session);
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) {
const char *e, *n;
char *s;
assert(path);
assert(uid);
/* Skip slices, if there are any */
e = skip_slices(path);
n = strchrnul(e, '/');
if (n - e < 5)
return -ENOENT;
if (memcmp(n - 5, ".user", 5) != 0)
return -ENOENT;
s = strndupa(e, n - e - 5);
if (!s)
return -ENOMEM;
return parse_uid(s, uid);
}
int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
_cleanup_free_ char *cgroup = NULL;
int r;
assert(uid);
r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
if (r < 0)
return r;
return cg_path_get_owner_uid(cgroup, uid);
}
int cg_controller_from_attr(const char *attr, char **controller) {
const char *dot;
char *c;
assert(attr);
assert(controller);
if (!filename_is_safe(attr))
return -EINVAL;
dot = strchr(attr, '.');
if (!dot) {
*controller = NULL;
return 0;
}
c = strndup(attr, dot - attr);
if (!c)
return -ENOMEM;
if (!cg_controller_is_valid(c, false)) {
free(c);
return -EINVAL;
}
*controller = c;
return 1;
}
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 \
"0123456789" \
"abcdefghijklmnopqrstuvwxyz" \
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
"_"
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, false))
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, false))
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;
}
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