src/lxc/cgroups/cgroup.h

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #ifndef __LXC_CGROUP_H
  25 #define __LXC_CGROUP_H
  26
  27 #include <stdbool.h>
  28 #include <stddef.h>
  29 #include <sys/types.h>
  30
  31 struct lxc_handler;
  32 struct lxc_conf;
  33 struct lxc_list;
  34
  35 typedef enum {
  36         CGROUP_LAYOUT_UNKNOWN = -1,
  37         CGROUP_LAYOUT_LEGACY  =  0,
  38         CGROUP_LAYOUT_HYBRID  =  1,
  39         CGROUP_LAYOUT_UNIFIED =  2,
  40 } cgroup_layout_t;
  41
  42 /* A descriptor for a mounted hierarchy
  43  *
  44  * @controllers
  45  * - legacy hierarchy
  46  *   Either NULL, or a null-terminated list of all the co-mounted controllers.
  47  * - unified hierarchy
  48  *   Either NULL, or a null-terminated list of all enabled controllers.
  49  *
  50  * @mountpoint
  51  * - The mountpoint we will use.
  52  * - legacy hierarchy
  53  *   It will be either /sys/fs/cgroup/controller or
  54  *   /sys/fs/cgroup/controllerlist.
  55  * - unified hierarchy
  56  *   It will either be /sys/fs/cgroup or /sys/fs/cgroup/<mountpoint-name>
  57  *   depending on whether this is a hybrid cgroup layout (mix of legacy and
  58  *   unified hierarchies) or a pure unified cgroup layout.
  59  *
  60  * @base_cgroup
  61  * - The cgroup under which the container cgroup path
  62  *   is created. This will be either the caller's cgroup (if not root), or
  63  *   init's cgroup (if root).
  64  *
  65  * @container_full_path
  66  * - The full path to the containers cgroup.
  67  *
  68  * @version
  69  * - legacy hierarchy
  70  *   If the hierarchy is a legacy hierarchy this will be set to
  71  *   CGROUP_SUPER_MAGIC.
  72  * - unified hierarchy
  73  *   If the hierarchy is a legacy hierarchy this will be set to
  74  *   CGROUP2_SUPER_MAGIC.
  75  */
  76 struct hierarchy {
  77         char **controllers;
  78         char *mountpoint;
  79         char *base_cgroup;
  80         char *container_full_path;
  81         int version;
  82 };
  83
  84 struct cgroup_ops {
  85         /* string constant */
  86         const char *driver;
  87
  88         /* string constant */
  89         const char *version;
  90
  91         /* What controllers is the container supposed to use. */
  92         char **cgroup_use;
  93         char *cgroup_pattern;
  94         char *container_cgroup;
  95
  96         /* @hierarchies
  97          * - A NULL-terminated array of struct hierarchy, one per legacy
  98          *   hierarchy. No duplicates. First sufficient, writeable mounted
  99          *   hierarchy wins.
 100          */
 101         struct hierarchy **hierarchies;
 102         struct hierarchy *unified;
 103
 104         /*
 105          * @cgroup_layout
 106          * - What cgroup layout the container is running with.
 107          *   - CGROUP_LAYOUT_UNKNOWN
 108          *     The cgroup layout could not be determined. This should be treated
 109          *     as an error condition.
 110          *   - CGROUP_LAYOUT_LEGACY
 111          *     The container is running with all controllers mounted into legacy
 112          *     cgroup hierarchies.
 113          *   - CGROUP_LAYOUT_HYBRID
 114          *     The container is running with at least one controller mounted
 115          *     into a legacy cgroup hierarchy and a mountpoint for the unified
 116          *     hierarchy. The unified hierarchy can be empty (no controllers
 117          *     enabled) or non-empty (controllers enabled).
 118          *   - CGROUP_LAYOUT_UNIFIED
 119          *     The container is running on a pure unified cgroup hierarchy. The
 120          *     unified hierarchy can be empty (no controllers enabled) or
 121          *     non-empty (controllers enabled).
 122          */
 123         cgroup_layout_t cgroup_layout;
 124
 125         bool (*data_init)(struct cgroup_ops *ops);
 126         void (*destroy)(struct cgroup_ops *ops, struct lxc_handler *handler);
 127         bool (*payload_create)(struct cgroup_ops *ops, struct lxc_handler *handler);
 128         bool (*payload_enter)(struct cgroup_ops *ops, pid_t pid);
 129         const char *(*get_cgroup)(struct cgroup_ops *ops, const char *controller);
 130         bool (*escape)(const struct cgroup_ops *ops, struct lxc_conf *conf);
 131         int (*num_hierarchies)(struct cgroup_ops *ops);
 132         bool (*get_hierarchies)(struct cgroup_ops *ops, int n, char ***out);
 133         int (*set)(struct cgroup_ops *ops, const char *filename,
 134                    const char *value, const char *name, const char *lxcpath);
 135         int (*get)(struct cgroup_ops *ops, const char *filename, char *value,
 136                    size_t len, const char *name, const char *lxcpath);
 137         bool (*unfreeze)(struct cgroup_ops *ops);
 138         bool (*setup_limits)(struct cgroup_ops *ops, struct lxc_conf *conf,
 139                              bool with_devices);
 140         bool (*chown)(struct cgroup_ops *ops, struct lxc_conf *conf);
 141         bool (*attach)(struct cgroup_ops *ops, const char *name,
 142                        const char *lxcpath, pid_t pid);
 143         bool (*mount)(struct cgroup_ops *ops, struct lxc_handler *handler,
 144                       const char *root, int type);
 145         int (*nrtasks)(struct cgroup_ops *ops);
 146 };
 147
 148 extern struct cgroup_ops *cgroup_init(struct lxc_conf *conf);
 149 extern void cgroup_exit(struct cgroup_ops *ops);
 150
 151 extern void prune_init_scope(char *cg);
 152
 153 #endif