src/cgroup.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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
  29 #include <libcgroup.h>
  30
  31 #include "cgroup.h"
  32 #include "cgroup-util.h"
  33 #include "log.h"
  34
  35 int cgroup_bonding_realize(CGroupBonding *b) {
  36         int r;
  37
  38         assert(b);
  39         assert(b->path);
  40         assert(b->controller);
  41
  42         if (b->realized)
  43                 return 0;
  44
  45         if ((r = cg_create(b->controller, b->path)) < 0)
  46                 return r;
  47
  48         b->realized = true;
  49
  50         if (b->only_us && b->clean_up)
  51                 cg_trim(b->controller, b->path, false);
  52
  53         return 0;
  54 }
  55
  56 int cgroup_bonding_realize_list(CGroupBonding *first) {
  57         CGroupBonding *b;
  58         int r;
  59
  60         LIST_FOREACH(by_unit, b, first)
  61                 if ((r = cgroup_bonding_realize(b)) < 0)
  62                         return r;
  63
  64         return 0;
  65 }
  66
  67 void cgroup_bonding_free(CGroupBonding *b) {
  68         assert(b);
  69
  70         if (b->unit) {
  71                 CGroupBonding *f;
  72
  73                 LIST_REMOVE(CGroupBonding, by_unit, b->unit->meta.cgroup_bondings, b);
  74
  75                 assert_se(f = hashmap_get(b->unit->meta.manager->cgroup_bondings, b->path));
  76                 LIST_REMOVE(CGroupBonding, by_path, f, b);
  77
  78                 if (f)
  79                         hashmap_replace(b->unit->meta.manager->cgroup_bondings, b->path, f);
  80                 else
  81                         hashmap_remove(b->unit->meta.manager->cgroup_bondings, b->path);
  82         }
  83
  84         if (b->realized && b->only_us && b->clean_up) {
  85
  86                 if (cgroup_bonding_is_empty(b) > 0)
  87                         cg_delete(b->controller, b->path);
  88                 else
  89                         cg_trim(b->controller, b->path, false);
  90         }
  91
  92         free(b->controller);
  93         free(b->path);
  94         free(b);
  95 }
  96
  97 void cgroup_bonding_free_list(CGroupBonding *first) {
  98         CGroupBonding *b, *n;
  99
 100         LIST_FOREACH_SAFE(by_unit, b, n, first)
 101                 cgroup_bonding_free(b);
 102 }
 103
 104 void cgroup_bonding_trim(CGroupBonding *b, bool delete_root) {
 105         assert(b);
 106
 107         if (b->realized && b->only_us && b->clean_up)
 108                 cg_trim(b->controller, b->path, delete_root);
 109 }
 110
 111 void cgroup_bonding_trim_list(CGroupBonding *first, bool delete_root) {
 112         CGroupBonding *b;
 113
 114         LIST_FOREACH(by_unit, b, first)
 115                 cgroup_bonding_trim(b, delete_root);
 116 }
 117
 118 int cgroup_bonding_install(CGroupBonding *b, pid_t pid) {
 119         int r;
 120
 121         assert(b);
 122         assert(pid >= 0);
 123
 124         if ((r = cg_create_and_attach(b->controller, b->path, pid)) < 0)
 125                 return r;
 126
 127         b->realized = true;
 128         return 0;
 129 }
 130
 131 int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid) {
 132         CGroupBonding *b;
 133         int r;
 134
 135         LIST_FOREACH(by_unit, b, first)
 136                 if ((r = cgroup_bonding_install(b, pid)) < 0)
 137                         return r;
 138
 139         return 0;
 140 }
 141
 142 int cgroup_bonding_kill(CGroupBonding *b, int sig) {
 143         int r;
 144
 145         assert(b);
 146         assert(sig >= 0);
 147
 148         if ((r = cgroup_bonding_realize(b)) < 0)
 149                 return r;
 150
 151         assert(b->realized);
 152
 153         return cg_kill_recursive(b->controller, b->path, sig, true);
 154 }
 155
 156 int cgroup_bonding_kill_list(CGroupBonding *first, int sig) {
 157         CGroupBonding *b;
 158         int r = -EAGAIN;
 159
 160         LIST_FOREACH(by_unit, b, first) {
 161                 if ((r = cgroup_bonding_kill(b, sig)) < 0) {
 162                         if (r == -EAGAIN || r == -ESRCH)
 163                                 continue;
 164
 165                         return r;
 166                 }
 167
 168                 return 0;
 169         }
 170
 171         return r;
 172 }
 173
 174 /* Returns 1 if the group is empty, 0 if it is not, -EAGAIN if we
 175  * cannot know */
 176 int cgroup_bonding_is_empty(CGroupBonding *b) {
 177         int r;
 178
 179         assert(b);
 180
 181         if ((r = cg_is_empty_recursive(b->controller, b->path, true)) < 0)
 182                 return r;
 183
 184         /* If it is empty it is empty */
 185         if (r > 0)
 186                 return 1;
 187
 188         /* It's not only us using this cgroup, so we just don't know */
 189         return b->only_us ? 0 : -EAGAIN;
 190 }
 191
 192 int cgroup_bonding_is_empty_list(CGroupBonding *first) {
 193         CGroupBonding *b;
 194
 195         LIST_FOREACH(by_unit, b, first) {
 196                 int r;
 197
 198                 if ((r = cgroup_bonding_is_empty(b)) < 0) {
 199                         /* If this returned -EAGAIN, then we don't know if the
 200                          * group is empty, so let's see if another group can
 201                          * tell us */
 202
 203                         if (r != -EAGAIN)
 204                                 return r;
 205                 } else
 206                         return r;
 207         }
 208
 209         return -EAGAIN;
 210 }
 211
 212 int manager_setup_cgroup(Manager *m) {
 213         char *cp;
 214         int r;
 215         pid_t pid;
 216         char suffix[32];
 217
 218         assert(m);
 219
 220         if ((r = cgroup_init()) != 0) {
 221                 log_error("Failed to initialize libcg: %s", cgroup_strerror(r));
 222                 return cg_translate_error(r, errno);
 223         }
 224
 225         free(m->cgroup_controller);
 226         if (!(m->cgroup_controller = strdup("name=systemd")))
 227                 return -ENOMEM;
 228
 229         free(m->cgroup_mount_point);
 230         m->cgroup_mount_point = NULL;
 231         if ((r = cgroup_get_subsys_mount_point(m->cgroup_controller, &m->cgroup_mount_point)))
 232                 return cg_translate_error(r, errno);
 233
 234         pid = getpid();
 235
 236         if ((r = cgroup_get_current_controller_path(pid, m->cgroup_controller, &cp)))
 237                 return cg_translate_error(r, errno);
 238
 239         snprintf(suffix, sizeof(suffix), "/systemd-%u", (unsigned) pid);
 240         char_array_0(suffix);
 241
 242         free(m->cgroup_hierarchy);
 243
 244         if (endswith(cp, suffix))
 245                 /* We probably got reexecuted and can continue to use our root cgroup */
 246                 m->cgroup_hierarchy = cp;
 247         else {
 248                 /* We need a new root cgroup */
 249
 250                 m->cgroup_hierarchy = NULL;
 251                 r = asprintf(&m->cgroup_hierarchy, "%s%s", streq(cp, "/") ? "" : cp, suffix);
 252                 free(cp);
 253
 254                 if (r < 0)
 255                         return -ENOMEM;
 256         }
 257
 258         log_debug("Using cgroup controller <%s>, hierarchy mounted at <%s>, using root group <%s>.",
 259                   m->cgroup_controller,
 260                   m->cgroup_mount_point,
 261                   m->cgroup_hierarchy);
 262
 263         if ((r = cg_install_release_agent(m->cgroup_controller, CGROUP_AGENT_PATH)) < 0)
 264                 log_warning("Failed to install release agent, ignoring: %s", strerror(-r));
 265         else
 266                 log_debug("Installed release agent, or already installed.");
 267
 268         if ((r = cg_create_and_attach(m->cgroup_controller, m->cgroup_hierarchy, 0)) < 0)
 269                 log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));
 270         else
 271                 log_debug("Created root group.");
 272
 273         return r;
 274 }
 275
 276 int manager_shutdown_cgroup(Manager *m) {
 277         assert(m);
 278
 279         if (!m->cgroup_controller || !m->cgroup_hierarchy)
 280                 return 0;
 281
 282         return cg_delete(m->cgroup_controller, m->cgroup_hierarchy);
 283 }
 284
 285 int cgroup_notify_empty(Manager *m, const char *group) {
 286         CGroupBonding *l, *b;
 287
 288         assert(m);
 289         assert(group);
 290
 291         if (!(l = hashmap_get(m->cgroup_bondings, group)))
 292                 return 0;
 293
 294         LIST_FOREACH(by_path, b, l) {
 295                 int t;
 296
 297                 if (!b->unit)
 298                         continue;
 299
 300                 if ((t = cgroup_bonding_is_empty_list(b)) < 0) {
 301
 302                         /* If we don't know, we don't know */
 303                         if (t != -EAGAIN)
 304                                 log_warning("Failed to check whether cgroup is empty: %s", strerror(errno));
 305
 306                         continue;
 307                 }
 308
 309                 if (t > 0)
 310                         if (UNIT_VTABLE(b->unit)->cgroup_notify_empty)
 311                                 UNIT_VTABLE(b->unit)->cgroup_notify_empty(b->unit);
 312         }
 313
 314         return 0;
 315 }
 316
 317 Unit* cgroup_unit_by_pid(Manager *m, pid_t pid) {
 318         CGroupBonding *l, *b;
 319         char *group = NULL;
 320         int r;
 321
 322         assert(m);
 323
 324         if (pid <= 1)
 325                 return NULL;
 326
 327         if ((r = cg_get_by_pid(m->cgroup_controller, pid, &group)))
 328                 return NULL;
 329
 330         l = hashmap_get(m->cgroup_bondings, group);
 331         free(group);
 332
 333         LIST_FOREACH(by_path, b, l) {
 334
 335                 if (!b->unit)
 336                         continue;
 337
 338                 if (b->only_us)
 339                         return b->unit;
 340         }
 341
 342         return NULL;
 343 }
 344
 345 CGroupBonding *cgroup_bonding_find_list(CGroupBonding *first, const char *controller) {
 346         CGroupBonding *b;
 347
 348         assert(controller);
 349
 350         LIST_FOREACH(by_unit, b, first)
 351                 if (streq(b->controller, controller))
 352                         return b;
 353
 354         return NULL;
 355 }
 356
 357 char *cgroup_bonding_to_string(CGroupBonding *b) {
 358         char *r;
 359
 360         assert(b);
 361
 362         if (asprintf(&r, "%s:%s", b->controller, b->path) < 0)
 363                 return NULL;
 364
 365         return r;
 366 }