unit.h

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #ifndef foounithfoo
   4 #define foounithfoo
   5
   6 /***
   7   This file is part of systemd.
   8
   9   Copyright 2010 Lennart Poettering
  10
  11   systemd is free software; you can redistribute it and/or modify it
  12   under the terms of the GNU General Public License as published by
  13   the Free Software Foundation; either version 2 of the License, or
  14   (at your option) any later version.
  15
  16   systemd is distributed in the hope that it will be useful, but
  17   WITHOUT ANY WARRANTY; without even the implied warranty of
  18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19   General Public License for more details.
  20
  21   You should have received a copy of the GNU General Public License
  22   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  23 ***/
  24
  25 #include <stdbool.h>
  26 #include <stdlib.h>
  27
  28 typedef union Unit Unit;
  29 typedef struct Meta Meta;
  30 typedef struct UnitVTable UnitVTable;
  31 typedef enum UnitType UnitType;
  32 typedef enum UnitLoadState UnitLoadState;
  33 typedef enum UnitActiveState UnitActiveState;
  34 typedef enum UnitDependency UnitDependency;
  35
  36 #include "set.h"
  37 #include "util.h"
  38 #include "list.h"
  39 #include "socket-util.h"
  40 #include "execute.h"
  41
  42 #define UNIT_NAME_MAX 128
  43 #define DEFAULT_TIMEOUT_USEC (20*USEC_PER_SEC)
  44 #define DEFAULT_RESTART_USEC (100*USEC_PER_MSEC)
  45
  46 typedef enum KillMode {
  47         KILL_CONTROL_GROUP = 0,
  48         KILL_PROCESS_GROUP,
  49         KILL_PROCESS,
  50         KILL_NONE,
  51         _KILL_MODE_MAX,
  52         _KILL_MODE_INVALID = -1
  53 } KillMode;
  54
  55 enum UnitType {
  56         UNIT_SERVICE = 0,
  57         UNIT_SOCKET,
  58         UNIT_TARGET,
  59         UNIT_DEVICE,
  60         UNIT_MOUNT,
  61         UNIT_AUTOMOUNT,
  62         UNIT_SNAPSHOT,
  63         UNIT_TIMER,
  64         UNIT_SWAP,
  65         _UNIT_TYPE_MAX,
  66         _UNIT_TYPE_INVALID = -1
  67 };
  68
  69 enum UnitLoadState {
  70         UNIT_STUB,
  71         UNIT_LOADED,
  72         UNIT_FAILED,
  73         UNIT_MERGED,
  74         _UNIT_LOAD_STATE_MAX,
  75         _UNIT_LOAD_STATE_INVALID = -1
  76 };
  77
  78 enum UnitActiveState {
  79         UNIT_ACTIVE,
  80         UNIT_ACTIVE_RELOADING,
  81         UNIT_INACTIVE,
  82         UNIT_ACTIVATING,
  83         UNIT_DEACTIVATING,
  84         _UNIT_ACTIVE_STATE_MAX,
  85         _UNIT_ACTIVE_STATE_INVALID = -1
  86 };
  87
  88 static inline bool UNIT_IS_ACTIVE_OR_RELOADING(UnitActiveState t) {
  89         return t == UNIT_ACTIVE || t == UNIT_ACTIVE_RELOADING;
  90 }
  91
  92 static inline bool UNIT_IS_ACTIVE_OR_ACTIVATING(UnitActiveState t) {
  93         return t == UNIT_ACTIVE || t == UNIT_ACTIVATING || t == UNIT_ACTIVE_RELOADING;
  94 }
  95
  96 static inline bool UNIT_IS_INACTIVE_OR_DEACTIVATING(UnitActiveState t) {
  97         return t == UNIT_INACTIVE || t == UNIT_DEACTIVATING;
  98 }
  99
 100 enum UnitDependency {
 101         /* Positive dependencies */
 102         UNIT_REQUIRES,
 103         UNIT_REQUIRES_OVERRIDABLE,
 104         UNIT_REQUISITE,
 105         UNIT_REQUISITE_OVERRIDABLE,
 106         UNIT_WANTS,
 107
 108         /* Inverse of the above */
 109         UNIT_REQUIRED_BY,             /* inverse of 'requires' and 'requisite' is 'required_by' */
 110         UNIT_REQUIRED_BY_OVERRIDABLE, /* inverse of 'soft_requires' and 'soft_requisite' is 'soft_required_by' */
 111         UNIT_WANTED_BY,               /* inverse of 'wants' */
 112
 113         /* Negative dependencies */
 114         UNIT_CONFLICTS,               /* inverse of 'conflicts' is 'conflicts' */
 115
 116         /* Order */
 117         UNIT_BEFORE,                  /* inverse of 'before' is 'after' and vice versa */
 118         UNIT_AFTER,
 119
 120         /* Reference information for GC logic */
 121         UNIT_REFERENCES,              /* Inverse of 'references' is 'referenced_by' */
 122         UNIT_REFERENCED_BY,
 123
 124         _UNIT_DEPENDENCY_MAX,
 125         _UNIT_DEPENDENCY_INVALID = -1
 126 };
 127
 128 #include "manager.h"
 129 #include "job.h"
 130 #include "cgroup.h"
 131
 132 struct Meta {
 133         Manager *manager;
 134
 135         UnitType type;
 136         UnitLoadState load_state;
 137         Unit *merged_into;
 138
 139         char *id; /* One name is special because we use it for identification. Points to an entry in the names set */
 140         char *instance;
 141
 142         Set *names;
 143         Set *dependencies[_UNIT_DEPENDENCY_MAX];
 144
 145         char *description;
 146         char *fragment_path; /* if loaded from a config file this is the primary path to it */
 147
 148         /* If there is something to do with this unit, then this is
 149          * the job for it */
 150         Job *job;
 151
 152         usec_t active_enter_timestamp;
 153         usec_t active_exit_timestamp;
 154
 155         /* Counterparts in the cgroup filesystem */
 156         CGroupBonding *cgroup_bondings;
 157
 158         /* Per type list */
 159         LIST_FIELDS(Meta, units_per_type);
 160
 161         /* Load queue */
 162         LIST_FIELDS(Meta, load_queue);
 163
 164         /* D-Bus queue */
 165         LIST_FIELDS(Meta, dbus_queue);
 166
 167         /* Cleanup queue */
 168         LIST_FIELDS(Meta, cleanup_queue);
 169
 170         /* GC queue */
 171         LIST_FIELDS(Meta, gc_queue);
 172
 173         /* Used during GC sweeps */
 174         unsigned gc_marker;
 175
 176         /* If we go down, pull down everything that depends on us, too */
 177         bool recursive_stop;
 178
 179         /* Garbage collect us we nobody wants or requires us anymore */
 180         bool stop_when_unneeded;
 181
 182         bool in_load_queue:1;
 183         bool in_dbus_queue:1;
 184         bool in_cleanup_queue:1;
 185         bool in_gc_queue:1;
 186
 187         bool sent_dbus_new_signal:1;
 188 };
 189
 190 #include "service.h"
 191 #include "timer.h"
 192 #include "socket.h"
 193 #include "target.h"
 194 #include "device.h"
 195 #include "mount.h"
 196 #include "automount.h"
 197 #include "snapshot.h"
 198 #include "swap.h"
 199
 200 union Unit {
 201         Meta meta;
 202         Service service;
 203         Timer timer;
 204         Socket socket;
 205         Target target;
 206         Device device;
 207         Mount mount;
 208         Automount automount;
 209         Snapshot snapshot;
 210         Swap swap;
 211 };
 212
 213 struct UnitVTable {
 214         const char *suffix;
 215
 216         /* This should reset all type-specific variables. This should
 217          * not allocate memory, and is called with zero-initialized
 218          * data. It should hence only initialize variables that need
 219          * to be set != 0. */
 220         void (*init)(Unit *u);
 221
 222         /* This should free all type-specific variables. It should be
 223          * idempotent. */
 224         void (*done)(Unit *u);
 225
 226         /* Actually load data from disk. This may fail, and should set
 227          * load_state to UNIT_LOADED, UNIT_MERGED or leave it at
 228          * UNIT_STUB if no configuration could be found. */
 229         int (*load)(Unit *u);
 230
 231         /* If a a lot of units got created via enumerate(), this is
 232          * where to actually set the state and call unit_notify(). */
 233         int (*coldplug)(Unit *u);
 234
 235         void (*dump)(Unit *u, FILE *f, const char *prefix);
 236
 237         int (*start)(Unit *u);
 238         int (*stop)(Unit *u);
 239         int (*reload)(Unit *u);
 240
 241         bool (*can_reload)(Unit *u);
 242
 243         /* Write all data that cannot be restored from other sources
 244          * away using unit_serialize_item() */
 245         int (*serialize)(Unit *u, FILE *f, FDSet *fds);
 246
 247         /* Restore one item from the serialization */
 248         int (*deserialize_item)(Unit *u, const char *key, const char *data, FDSet *fds);
 249
 250         /* Boils down the more complex internal state of this unit to
 251          * a simpler one that the engine can understand */
 252         UnitActiveState (*active_state)(Unit *u);
 253
 254         /* Returns the substate specific to this unit type as
 255          * string. This is purely information so that we can give the
 256          * user a more finegrained explanation in which actual state a
 257          * unit is in. */
 258         const char* (*sub_state_to_string)(Unit *u);
 259
 260         /* Return true when there is reason to keep this entry around
 261          * even nothing references it and it isn't active in any
 262          * way */
 263         bool (*check_gc)(Unit *u);
 264
 265         /* Return true when this unit is suitable for snapshotting */
 266         bool (*check_snapshot)(Unit *u);
 267
 268         void (*fd_event)(Unit *u, int fd, uint32_t events, Watch *w);
 269         void (*sigchld_event)(Unit *u, pid_t pid, int code, int status);
 270         void (*timer_event)(Unit *u, uint64_t n_elapsed, Watch *w);
 271
 272         /* Called whenever any of the cgroups this unit watches for
 273          * ran empty */
 274         void (*cgroup_notify_empty)(Unit *u);
 275
 276         /* Called whenever a name thus Unit registered for comes or
 277          * goes away. */
 278         void (*bus_name_owner_change)(Unit *u, const char *name, const char *old_owner, const char *new_owner);
 279
 280         /* Called whenever a bus PID lookup finishes */
 281         void (*bus_query_pid_done)(Unit *u, const char *name, pid_t pid);
 282
 283         /* Called for each message received on the bus */
 284         DBusHandlerResult (*bus_message_handler)(Unit *u, DBusMessage *message);
 285
 286         /* This is called for each unit type and should be used to
 287          * enumerate existing devices and load them. However,
 288          * everything that is loaded here should still stay in
 289          * inactive state. It is the job of the coldplug() call above
 290          * to put the units into the initial state.  */
 291         int (*enumerate)(Manager *m);
 292
 293         /* Type specific cleanups. */
 294         void (*shutdown)(Manager *m);
 295
 296         /* Can units of this type have multiple names? */
 297         bool no_alias:1;
 298
 299         /* If true units of this types can never have "Requires"
 300          * dependencies, because state changes can only be observed,
 301          * not triggered */
 302         bool no_requires:1;
 303
 304         /* Instances make no sense for this type */
 305         bool no_instances:1;
 306
 307         /* Exclude this type from snapshots */
 308         bool no_snapshots:1;
 309
 310         /* Exclude from automatic gc */
 311         bool no_gc:1;
 312
 313         /* Exclude from isolation requests */
 314         bool no_isolate:1;
 315 };
 316
 317 extern const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX];
 318
 319 #define UNIT_VTABLE(u) unit_vtable[(u)->meta.type]
 320
 321 /* For casting a unit into the various unit types */
 322 #define DEFINE_CAST(UPPERCASE, MixedCase)                               \
 323         static inline MixedCase* UPPERCASE(Unit *u) {                   \
 324                 if (!u || u->meta.type != UNIT_##UPPERCASE)             \
 325                         return NULL;                                    \
 326                                                                         \
 327                 return (MixedCase*) u;                                  \
 328         }
 329
 330 /* For casting the various unit types into a unit */
 331 #define UNIT(u) ((Unit*) (u))
 332
 333 DEFINE_CAST(SOCKET, Socket);
 334 DEFINE_CAST(TIMER, Timer);
 335 DEFINE_CAST(SERVICE, Service);
 336 DEFINE_CAST(TARGET, Target);
 337 DEFINE_CAST(DEVICE, Device);
 338 DEFINE_CAST(MOUNT, Mount);
 339 DEFINE_CAST(AUTOMOUNT, Automount);
 340 DEFINE_CAST(SNAPSHOT, Snapshot);
 341 DEFINE_CAST(SWAP, Swap);
 342
 343 Unit *unit_new(Manager *m);
 344 void unit_free(Unit *u);
 345
 346 int unit_add_name(Unit *u, const char *name);
 347
 348 int unit_add_dependency(Unit *u, UnitDependency d, Unit *other, bool add_reference);
 349 int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
 350 int unit_add_dependency_by_name_inverse(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
 351
 352 int unit_add_exec_dependencies(Unit *u, ExecContext *c);
 353
 354 int unit_add_cgroup(Unit *u, CGroupBonding *b);
 355 int unit_add_cgroup_from_text(Unit *u, const char *name);
 356 int unit_add_default_cgroup(Unit *u);
 357 CGroupBonding* unit_get_default_cgroup(Unit *u);
 358
 359 int unit_choose_id(Unit *u, const char *name);
 360 int unit_set_description(Unit *u, const char *description);
 361
 362 bool unit_check_gc(Unit *u);
 363
 364 void unit_add_to_load_queue(Unit *u);
 365 void unit_add_to_dbus_queue(Unit *u);
 366 void unit_add_to_cleanup_queue(Unit *u);
 367 void unit_add_to_gc_queue(Unit *u);
 368
 369 int unit_merge(Unit *u, Unit *other);
 370 int unit_merge_by_name(Unit *u, const char *other);
 371
 372 Unit *unit_follow_merge(Unit *u);
 373
 374 int unit_load_fragment_and_dropin(Unit *u);
 375 int unit_load_fragment_and_dropin_optional(Unit *u);
 376 int unit_load_nop(Unit *u);
 377 int unit_load(Unit *unit);
 378
 379 const char *unit_description(Unit *u);
 380
 381 bool unit_has_name(Unit *u, const char *name);
 382
 383 UnitActiveState unit_active_state(Unit *u);
 384
 385 const char* unit_sub_state_to_string(Unit *u);
 386
 387 void unit_dump(Unit *u, FILE *f, const char *prefix);
 388
 389 bool unit_can_reload(Unit *u);
 390 bool unit_can_start(Unit *u);
 391
 392 int unit_start(Unit *u);
 393 int unit_stop(Unit *u);
 394 int unit_reload(Unit *u);
 395
 396 void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns);
 397
 398 int unit_watch_fd(Unit *u, int fd, uint32_t events, Watch *w);
 399 void unit_unwatch_fd(Unit *u, Watch *w);
 400
 401 int unit_watch_pid(Unit *u, pid_t pid);
 402 void unit_unwatch_pid(Unit *u, pid_t pid);
 403
 404 int unit_watch_timer(Unit *u, usec_t delay, Watch *w);
 405 void unit_unwatch_timer(Unit *u, Watch *w);
 406
 407 int unit_watch_bus_name(Unit *u, const char *name);
 408 void unit_unwatch_bus_name(Unit *u, const char *name);
 409
 410 bool unit_job_is_applicable(Unit *u, JobType j);
 411
 412 int set_unit_path(const char *p);
 413
 414 char *unit_dbus_path(Unit *u);
 415
 416 int unit_load_related_unit(Unit *u, const char *type, Unit **_found);
 417 int unit_get_related_unit(Unit *u, const char *type, Unit **_found);
 418
 419 char *unit_name_printf(Unit *u, const char* text);
 420 char *unit_full_printf(Unit *u, const char *text);
 421 char **unit_full_printf_strv(Unit *u, char **l);
 422
 423 bool unit_can_serialize(Unit *u);
 424 int unit_serialize(Unit *u, FILE *f, FDSet *fds);
 425 void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *value, ...) _printf_attr(4,5);
 426 void unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value);
 427 int unit_deserialize(Unit *u, FILE *f, FDSet *fds);
 428
 429 const char *unit_type_to_string(UnitType i);
 430 UnitType unit_type_from_string(const char *s);
 431
 432 const char *unit_load_state_to_string(UnitLoadState i);
 433 UnitLoadState unit_load_state_from_string(const char *s);
 434
 435 const char *unit_active_state_to_string(UnitActiveState i);
 436 UnitActiveState unit_active_state_from_string(const char *s);
 437
 438 const char *unit_dependency_to_string(UnitDependency i);
 439 UnitDependency unit_dependency_from_string(const char *s);
 440
 441 const char *kill_mode_to_string(KillMode k);
 442 KillMode kill_mode_from_string(const char *s);
 443
 444 #endif