src/lxc/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 #ifndef _ncgroup_h
  24 #define _ncgroup_h
  25 #include <stdbool.h>
  26 #include <stdint.h>
  27 #include <stddef.h>
  28
  29 #include "state.h"
  30
  31 struct cgroup_hierarchy;
  32 struct cgroup_meta_data;
  33 struct cgroup_mount_point;
  34
  35 /*
  36  * cgroup_meta_data: the metadata about the cgroup infrastructure on this
  37  *                   host
  38  */
  39 struct cgroup_meta_data {
  40         ptrdiff_t ref; /* simple refcount */
  41         struct cgroup_hierarchy **hierarchies;
  42         struct cgroup_mount_point **mount_points;
  43         int maximum_hierarchy;
  44 };
  45
  46 /*
  47  * cgroup_hierarchy: describes a single cgroup hierarchy
  48  *                   (may have multiple mount points)
  49  */
  50 struct cgroup_hierarchy {
  51         int index;
  52         bool used; /* false if the hierarchy should be ignored by lxc */
  53         char **subsystems;
  54         struct cgroup_mount_point *rw_absolute_mount_point;
  55         struct cgroup_mount_point *ro_absolute_mount_point;
  56         struct cgroup_mount_point **all_mount_points;
  57         size_t all_mount_point_capacity;
  58 };
  59
  60 /*
  61  * cgroup_mount_point: a mount point to where a hierarchy
  62  *                     is mounted to
  63  */
  64 struct cgroup_mount_point {
  65         struct cgroup_hierarchy *hierarchy;
  66         char *mount_point;
  67         char *mount_prefix;
  68         bool read_only;
  69 };
  70
  71 /*
  72  * cgroup_process_info: describes the membership of a
  73  *                      process to the different cgroup
  74  *                      hierarchies
  75  *
  76  * Note this is the per-process info tracked by the cgfs_ops.
  77  * This is not used with cgmanager.
  78  */
  79 struct cgroup_process_info {
  80         struct cgroup_process_info *next;
  81         struct cgroup_meta_data *meta_ref;
  82         struct cgroup_hierarchy *hierarchy;
  83         char *cgroup_path;
  84         char *cgroup_path_sub;
  85         char **created_paths;
  86         size_t created_paths_capacity;
  87         size_t created_paths_count;
  88         struct cgroup_mount_point *designated_mount_point;
  89 };
  90
  91 /* meta data management:
  92  *    lxc_cgroup_load_meta  loads the meta data (using subsystem
  93  *                          whitelist from main lxc configuration)
  94  *    lxc_cgroup_load_meta2 does the same, but allows one to specify
  95  *                          a custom whitelist
  96  *    lxc_cgroup_get_meta   increments the refcount of a meta data
  97  *                          object
  98  *    lxc_cgroup_put_meta   decrements the refcount of a meta data
  99  *                          object, potentially destroying it
 100  */
 101 extern struct cgroup_meta_data *lxc_cgroup_load_meta();
 102 extern struct cgroup_meta_data *lxc_cgroup_load_meta2(const char **subsystem_whitelist);
 103 extern struct cgroup_meta_data *lxc_cgroup_get_meta(struct cgroup_meta_data *meta_data);
 104 extern struct cgroup_meta_data *lxc_cgroup_put_meta(struct cgroup_meta_data *meta_data);
 105
 106 /* find the hierarchy corresponding to a given subsystem */
 107 extern struct cgroup_hierarchy *lxc_cgroup_find_hierarchy(struct cgroup_meta_data *meta_data, const char *subsystem);
 108
 109 /* find a mount point for a given hierarchy that has access to the cgroup in 'cgroup' and (if wanted) is writable */
 110 extern struct cgroup_mount_point *lxc_cgroup_find_mount_point(struct cgroup_hierarchy *hierarchy, const char *group, bool should_be_writable);
 111
 112 /* all-in-one: find a mount point for a given hierarchy that has access to the cgroup and return the correct path within */
 113 extern char *lxc_cgroup_find_abs_path(const char *subsystem, const char *group, bool should_be_writable, const char *suffix);
 114
 115 /* determine the cgroup membership of a given process */
 116 extern struct cgroup_process_info *lxc_cgroup_process_info_get(pid_t pid, struct cgroup_meta_data *meta);
 117 extern struct cgroup_process_info *lxc_cgroup_process_info_get_init(struct cgroup_meta_data *meta);
 118 extern struct cgroup_process_info *lxc_cgroup_process_info_get_self(struct cgroup_meta_data *meta);
 119
 120 /* create a new cgroup */
 121 extern struct cgroup_process_info *lxc_cgroup_create(const char *name, const char *path_pattern, struct cgroup_meta_data *meta_data, const char *sub_pattern);
 122 extern int lxc_cgroup_create_legacy(struct cgroup_process_info *base_info, const char *name, pid_t pid);
 123
 124 /* get the cgroup membership of a given container */
 125 extern struct cgroup_process_info *lxc_cgroup_get_container_info(const char *name, const char *lxcpath, struct cgroup_meta_data *meta_data);
 126
 127 /* move a processs to the cgroups specified by the membership TODO - deprecated, switch users to cgroup_enter() */
 128 extern int lxc_cgroupfs_enter(struct cgroup_process_info *info, pid_t pid, bool enter_sub);
 129
 130 /* free process membership information */
 131 extern void lxc_cgroup_process_info_free(struct cgroup_process_info *info);
 132 extern void lxc_cgroup_process_info_free_and_remove(struct cgroup_process_info *info);
 133
 134 struct lxc_handler;
 135 extern char *lxc_cgroup_get_hierarchy_path(const char *subsystem, const char *name, const char *lxcpath);
 136 extern char *lxc_cgroup_get_hierarchy_abs_path_handler(const char *subsystem, struct lxc_handler *handler);
 137 extern char *lxc_cgroup_get_hierarchy_abs_path(const char *subsystem, const char *name, const char *lxcpath);
 138 extern int lxc_cgroup_set_handler(const char *filename, const char *value, struct lxc_handler *handler);
 139 extern int lxc_cgroup_get_handler(const char *filename, char *value, size_t len, struct lxc_handler *handler);
 140
 141 /*
 142  * lxc_cgroup_path_get: Get the absolute pathname for a cgroup
 143  * file for a running container.
 144  *
 145  * @filename  : the file of interest (e.g. "freezer.state") or
 146  *              the subsystem name (e.g. "freezer") in which case
 147  *              the directory where the cgroup may be modified
 148  *              will be returned
 149  * @name      : name of container to connect to
 150  * @lxcpath   : the lxcpath in which the container is running
 151  *
 152  * This is the exported function, which determines cgpath from the
 153  * lxc-start of the @name container running in @lxcpath.
 154  *
 155  * Returns path on success, NULL on error. The caller must free()
 156  * the returned path.
 157  */
 158 extern char *lxc_cgroup_path_get(const char *filename, const char *name,
 159                                  const char *lxcpath);
 160
 161 struct lxc_list;
 162 extern int lxc_setup_cgroup_without_devices(struct lxc_handler *h, struct lxc_list *cgroup_settings);
 163 extern int lxc_setup_cgroup_devices(struct lxc_handler *h, struct lxc_list *cgroup_settings);
 164
 165 extern int lxc_cgroup_nrtasks_handler(struct lxc_handler *handler);
 166
 167 extern int do_unfreeze(int freeze, const char *name, const char *lxcpath);
 168 extern int freeze_unfreeze(const char *name, int freeze, const char *lxcpath);
 169 extern const char *lxc_state2str(lxc_state_t state);
 170 extern lxc_state_t freezer_state(const char *name, const char *lxcpath);
 171 /* per-backend cgroup hooks */
 172 struct cgroup_ops {
 173         void (*destroy)(struct lxc_handler *handler);
 174         bool (*init)(struct lxc_handler *handler);
 175         bool (*create)(struct lxc_handler *handler);
 176         bool (*enter)(struct lxc_handler *handler);
 177         bool (*create_legacy)(struct lxc_handler *handler);
 178         char *(*get_cgroup)(struct lxc_handler *handler, const char *subsystem);
 179         int (*set)(const char *filename, const char *value, const char *name, const char *lxcpath);
 180         int (*get)(const char *filename, char *value, size_t len, const char *name, const char *lxcpath);
 181         int (*unfreeze_fromhandler)(struct lxc_handler *handler);
 182         bool (*setup_limits)(struct lxc_handler *handler, bool with_devices);
 183         bool (*chown)(struct lxc_handler *handler);
 184         const char *name;
 185 };
 186
 187 /*
 188  * cgroup-related data for backend use in start/stop of a
 189  * container.  This is tacked to the lxc_handler.
 190  */
 191 struct lxc_cgroup_info {
 192         /* handlers to actually do the cgroup stuff */
 193         struct cgroup_ops *ops;
 194         /* extra data for the cgroup_ops, i.e. mountpoints for fs backend */
 195         void *data;
 196         const char *cgroup_pattern;
 197 };
 198
 199 extern int lxc_setup_mount_cgroup(const char *root, struct lxc_cgroup_info *base_info, int type);
 200
 201 struct cgfs_data {
 202         struct cgroup_meta_data *meta;
 203         struct cgroup_process_info *info;
 204 };
 205
 206 /*
 207  * backend-independent cgroup handlers
 208  */
 209 extern void cgroup_destroy(struct lxc_handler *handler);
 210 extern bool cgroup_init(struct lxc_handler *handler);
 211 extern bool cgroup_create(struct lxc_handler *handler);
 212 extern bool cgroup_setup_limits(struct lxc_handler *handler, bool with_devices);
 213 extern bool cgroup_chown(struct lxc_handler *handler);
 214 extern bool cgroup_enter(struct lxc_handler *handler);
 215 extern void cgroup_cleanup(struct lxc_handler *handler);
 216 extern bool cgroup_create_legacy(struct lxc_handler *handler);
 217 extern char *cgroup_get_cgroup(struct lxc_handler *handler, const char *subsystem);
 218 extern int lxc_cgroup_set(const char *filename, const char *value, const char *name, const char *lxcpath);
 219 extern int lxc_cgroup_get(const char *filename, char *value, size_t len, const char *name, const char *lxcpath);
 220 extern int lxc_unfreeze_fromhandler(struct lxc_handler *handler);
 221
 222 #endif