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 }