chiark / gitweb /
man: properly refer to $MAINPID instead of $(MAINPID) which doesnt work anymore
[elogind.git] / src / cgroup.c
1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2
3 /***
4   This file is part of systemd.
5
6   Copyright 2010 Lennart Poettering
7
8   systemd is free software; you can redistribute it and/or modify it
9   under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   systemd is distributed in the hope that it will be useful, but
14   WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16   General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 ***/
21
22 #include <errno.h>
23 #include <assert.h>
24 #include <unistd.h>
25 #include <sys/types.h>
26 #include <signal.h>
27 #include <sys/mount.h>
28 #include <fcntl.h>
29
30 #include "cgroup.h"
31 #include "cgroup-util.h"
32 #include "log.h"
33
34 int cgroup_bonding_realize(CGroupBonding *b) {
35         int r;
36
37         assert(b);
38         assert(b->path);
39         assert(b->controller);
40
41         if (b->realized)
42                 return 0;
43
44         if ((r = cg_create(b->controller, b->path)) < 0)
45                 return r;
46
47         b->realized = true;
48
49         if (b->only_us && b->clean_up)
50                 cg_trim(b->controller, b->path, false);
51
52         return 0;
53 }
54
55 int cgroup_bonding_realize_list(CGroupBonding *first) {
56         CGroupBonding *b;
57         int r;
58
59         LIST_FOREACH(by_unit, b, first)
60                 if ((r = cgroup_bonding_realize(b)) < 0)
61                         return r;
62
63         return 0;
64 }
65
66 void cgroup_bonding_free(CGroupBonding *b) {
67         assert(b);
68
69         if (b->unit) {
70                 CGroupBonding *f;
71
72                 LIST_REMOVE(CGroupBonding, by_unit, b->unit->meta.cgroup_bondings, b);
73
74                 assert_se(f = hashmap_get(b->unit->meta.manager->cgroup_bondings, b->path));
75                 LIST_REMOVE(CGroupBonding, by_path, f, b);
76
77                 if (f)
78                         hashmap_replace(b->unit->meta.manager->cgroup_bondings, b->path, f);
79                 else
80                         hashmap_remove(b->unit->meta.manager->cgroup_bondings, b->path);
81         }
82
83         if (b->realized && b->only_us && b->clean_up) {
84
85                 if (cgroup_bonding_is_empty(b) > 0)
86                         cg_delete(b->controller, b->path);
87                 else
88                         cg_trim(b->controller, b->path, false);
89         }
90
91         free(b->controller);
92         free(b->path);
93         free(b);
94 }
95
96 void cgroup_bonding_free_list(CGroupBonding *first) {
97         CGroupBonding *b, *n;
98
99         LIST_FOREACH_SAFE(by_unit, b, n, first)
100                 cgroup_bonding_free(b);
101 }
102
103 void cgroup_bonding_trim(CGroupBonding *b, bool delete_root) {
104         assert(b);
105
106         if (b->realized && b->only_us && b->clean_up)
107                 cg_trim(b->controller, b->path, delete_root);
108 }
109
110 void cgroup_bonding_trim_list(CGroupBonding *first, bool delete_root) {
111         CGroupBonding *b;
112
113         LIST_FOREACH(by_unit, b, first)
114                 cgroup_bonding_trim(b, delete_root);
115 }
116
117 int cgroup_bonding_install(CGroupBonding *b, pid_t pid) {
118         int r;
119
120         assert(b);
121         assert(pid >= 0);
122
123         if ((r = cg_create_and_attach(b->controller, b->path, pid)) < 0)
124                 return r;
125
126         b->realized = true;
127         return 0;
128 }
129
130 int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid) {
131         CGroupBonding *b;
132         int r;
133
134         LIST_FOREACH(by_unit, b, first)
135                 if ((r = cgroup_bonding_install(b, pid)) < 0)
136                         return r;
137
138         return 0;
139 }
140
141 int cgroup_bonding_kill(CGroupBonding *b, int sig, Set *s) {
142         int r;
143
144         assert(b);
145         assert(sig >= 0);
146
147         if ((r = cgroup_bonding_realize(b)) < 0)
148                 return r;
149
150         assert(b->realized);
151
152         return cg_kill_recursive(b->controller, b->path, sig, true, false, s);
153 }
154
155 int cgroup_bonding_kill_list(CGroupBonding *first, int sig, Set *s) {
156         CGroupBonding *b;
157         Set *allocated_set = NULL;
158         int ret = -EAGAIN, r;
159
160         if (!s)
161                 if (!(s = allocated_set = set_new(trivial_hash_func, trivial_compare_func)))
162                         return -ENOMEM;
163
164         LIST_FOREACH(by_unit, b, first) {
165                 if ((r = cgroup_bonding_kill(b, sig, s)) < 0) {
166                         if (r == -EAGAIN || r == -ESRCH)
167                                 continue;
168
169                         ret = r;
170                         goto finish;
171                 }
172
173                 if (ret < 0 || r > 0)
174                         ret = r;
175         }
176
177 finish:
178         if (allocated_set)
179                 set_free(allocated_set);
180
181         return ret;
182 }
183
184 /* Returns 1 if the group is empty, 0 if it is not, -EAGAIN if we
185  * cannot know */
186 int cgroup_bonding_is_empty(CGroupBonding *b) {
187         int r;
188
189         assert(b);
190
191         if ((r = cg_is_empty_recursive(b->controller, b->path, true)) < 0)
192                 return r;
193
194         /* If it is empty it is empty */
195         if (r > 0)
196                 return 1;
197
198         /* It's not only us using this cgroup, so we just don't know */
199         return b->only_us ? 0 : -EAGAIN;
200 }
201
202 int cgroup_bonding_is_empty_list(CGroupBonding *first) {
203         CGroupBonding *b;
204
205         LIST_FOREACH(by_unit, b, first) {
206                 int r;
207
208                 if ((r = cgroup_bonding_is_empty(b)) < 0) {
209                         /* If this returned -EAGAIN, then we don't know if the
210                          * group is empty, so let's see if another group can
211                          * tell us */
212
213                         if (r != -EAGAIN)
214                                 return r;
215                 } else
216                         return r;
217         }
218
219         return -EAGAIN;
220 }
221
222 int manager_setup_cgroup(Manager *m) {
223         char *current = NULL, *path = NULL;
224         int r;
225         char suffix[32];
226
227         assert(m);
228
229         /* 1. Determine hierarchy */
230         if ((r = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 0, &current)) < 0)
231                 goto finish;
232
233         snprintf(suffix, sizeof(suffix), "/systemd-%lu", (unsigned long) getpid());
234         char_array_0(suffix);
235
236         free(m->cgroup_hierarchy);
237         if (endswith(current, suffix)) {
238                 /* We probably got reexecuted and can continue to use our root cgroup */
239                 m->cgroup_hierarchy = current;
240                 current = NULL;
241
242         } else {
243                 /* We need a new root cgroup */
244                 m->cgroup_hierarchy = NULL;
245                 if (asprintf(&m->cgroup_hierarchy, "%s%s", streq(current, "/") ? "" : current, suffix) < 0) {
246                         r = -ENOMEM;
247                         goto finish;
248                 }
249         }
250
251         /* 2. Show data */
252         if ((r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, NULL, &path)) < 0)
253                 goto finish;
254
255         log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
256
257         /* 3. Install agent */
258         if ((r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, CGROUP_AGENT_PATH)) < 0)
259                 log_warning("Failed to install release agent, ignoring: %s", strerror(-r));
260         else if (r > 0)
261                 log_debug("Installed release agent.");
262         else
263                 log_debug("Release agent already installed.");
264
265         /* 4. Realize the group */
266         if ((r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, 0)) < 0) {
267                 log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));
268                 goto finish;
269         }
270
271         /* 5. And pin it, so that it cannot be unmounted */
272         if (m->pin_cgroupfs_fd >= 0)
273                 close_nointr_nofail(m->pin_cgroupfs_fd);
274
275         if ((m->pin_cgroupfs_fd = open(path, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY|O_NONBLOCK)) < 0) {
276                 r = -errno;
277                 goto finish;
278         }
279
280         log_debug("Created root group.");
281
282 finish:
283         free(current);
284         free(path);
285
286         return r;
287 }
288
289 void manager_shutdown_cgroup(Manager *m, bool delete) {
290         assert(m);
291
292         if (delete && m->cgroup_hierarchy)
293                 cg_delete(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy);
294
295         if (m->pin_cgroupfs_fd >= 0) {
296                 close_nointr_nofail(m->pin_cgroupfs_fd);
297                 m->pin_cgroupfs_fd = -1;
298         }
299
300         free(m->cgroup_hierarchy);
301         m->cgroup_hierarchy = NULL;
302 }
303
304 int cgroup_notify_empty(Manager *m, const char *group) {
305         CGroupBonding *l, *b;
306
307         assert(m);
308         assert(group);
309
310         if (!(l = hashmap_get(m->cgroup_bondings, group)))
311                 return 0;
312
313         LIST_FOREACH(by_path, b, l) {
314                 int t;
315
316                 if (!b->unit)
317                         continue;
318
319                 if ((t = cgroup_bonding_is_empty_list(b)) < 0) {
320
321                         /* If we don't know, we don't know */
322                         if (t != -EAGAIN)
323                                 log_warning("Failed to check whether cgroup is empty: %s", strerror(errno));
324
325                         continue;
326                 }
327
328                 if (t > 0)
329                         if (UNIT_VTABLE(b->unit)->cgroup_notify_empty)
330                                 UNIT_VTABLE(b->unit)->cgroup_notify_empty(b->unit);
331         }
332
333         return 0;
334 }
335
336 Unit* cgroup_unit_by_pid(Manager *m, pid_t pid) {
337         CGroupBonding *l, *b;
338         char *group = NULL;
339
340         assert(m);
341
342         if (pid <= 1)
343                 return NULL;
344
345         if (cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, pid, &group) < 0)
346                 return NULL;
347
348         l = hashmap_get(m->cgroup_bondings, group);
349
350         if (!l) {
351                 char *slash;
352
353                 while ((slash = strrchr(group, '/'))) {
354                         if (slash == group)
355                                 break;
356
357                         *slash = 0;
358
359                         if ((l = hashmap_get(m->cgroup_bondings, group)))
360                                 break;
361                 }
362         }
363
364         free(group);
365
366         LIST_FOREACH(by_path, b, l) {
367
368                 if (!b->unit)
369                         continue;
370
371                 if (b->only_us)
372                         return b->unit;
373         }
374
375         return NULL;
376 }
377
378 CGroupBonding *cgroup_bonding_find_list(CGroupBonding *first, const char *controller) {
379         CGroupBonding *b;
380
381         assert(controller);
382
383         LIST_FOREACH(by_unit, b, first)
384                 if (streq(b->controller, controller))
385                         return b;
386
387         return NULL;
388 }
389
390 char *cgroup_bonding_to_string(CGroupBonding *b) {
391         char *r;
392
393         assert(b);
394
395         if (asprintf(&r, "%s:%s", b->controller, b->path) < 0)
396                 return NULL;
397
398         return r;
399 }