src/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 256
  43 #define DEFAULT_TIMEOUT_USEC (60*USEC_PER_SEC)
  44 #define DEFAULT_RESTART_USEC (100*USEC_PER_MSEC)
  45
  46 enum UnitType {
  47         UNIT_SERVICE = 0,
  48         UNIT_SOCKET,
  49         UNIT_TARGET,
  50         UNIT_DEVICE,
  51         UNIT_MOUNT,
  52         UNIT_AUTOMOUNT,
  53         UNIT_SNAPSHOT,
  54         UNIT_TIMER,
  55         UNIT_SWAP,
  56         UNIT_PATH,
  57         _UNIT_TYPE_MAX,
  58         _UNIT_TYPE_INVALID = -1
  59 };
  60
  61 enum UnitLoadState {
  62         UNIT_STUB,
  63         UNIT_LOADED,
  64         UNIT_FAILED,
  65         UNIT_MERGED,
  66         _UNIT_LOAD_STATE_MAX,
  67         _UNIT_LOAD_STATE_INVALID = -1
  68 };
  69
  70 enum UnitActiveState {
  71         UNIT_ACTIVE,
  72         UNIT_RELOADING,
  73         UNIT_INACTIVE,
  74         UNIT_MAINTENANCE,
  75         UNIT_ACTIVATING,
  76         UNIT_DEACTIVATING,
  77         _UNIT_ACTIVE_STATE_MAX,
  78         _UNIT_ACTIVE_STATE_INVALID = -1
  79 };
  80
  81 static inline bool UNIT_IS_ACTIVE_OR_RELOADING(UnitActiveState t) {
  82         return t == UNIT_ACTIVE || t == UNIT_RELOADING;
  83 }
  84
  85 static inline bool UNIT_IS_ACTIVE_OR_ACTIVATING(UnitActiveState t) {
  86         return t == UNIT_ACTIVE || t == UNIT_ACTIVATING || t == UNIT_RELOADING;
  87 }
  88
  89 static inline bool UNIT_IS_INACTIVE_OR_DEACTIVATING(UnitActiveState t) {
  90         return t == UNIT_INACTIVE || t == UNIT_MAINTENANCE || t == UNIT_DEACTIVATING;
  91 }
  92
  93 static inline bool UNIT_IS_INACTIVE_OR_MAINTENANCE(UnitActiveState t) {
  94         return t == UNIT_INACTIVE || t == UNIT_MAINTENANCE;
  95 }
  96
  97 enum UnitDependency {
  98         /* Positive dependencies */
  99         UNIT_REQUIRES,
 100         UNIT_REQUIRES_OVERRIDABLE,
 101         UNIT_REQUISITE,
 102         UNIT_REQUISITE_OVERRIDABLE,
 103         UNIT_WANTS,
 104
 105         /* Inverse of the above */
 106         UNIT_REQUIRED_BY,             /* inverse of 'requires' and 'requisite' is 'required_by' */
 107         UNIT_REQUIRED_BY_OVERRIDABLE, /* inverse of 'soft_requires' and 'soft_requisite' is 'soft_required_by' */
 108         UNIT_WANTED_BY,               /* inverse of 'wants' */
 109
 110         /* Negative dependencies */
 111         UNIT_CONFLICTS,               /* inverse of 'conflicts' is 'conflicts' */
 112
 113         /* Order */
 114         UNIT_BEFORE,                  /* inverse of 'before' is 'after' and vice versa */
 115         UNIT_AFTER,
 116
 117         /* Reference information for GC logic */
 118         UNIT_REFERENCES,              /* Inverse of 'references' is 'referenced_by' */
 119         UNIT_REFERENCED_BY,
 120
 121         _UNIT_DEPENDENCY_MAX,
 122         _UNIT_DEPENDENCY_INVALID = -1
 123 };
 124
 125 #include "manager.h"
 126 #include "job.h"
 127 #include "cgroup.h"
 128
 129 struct Meta {
 130         Manager *manager;
 131
 132         UnitType type;
 133         UnitLoadState load_state;
 134         Unit *merged_into;
 135
 136         char *id; /* One name is special because we use it for identification. Points to an entry in the names set */
 137         char *instance;
 138
 139         Set *names;
 140         Set *dependencies[_UNIT_DEPENDENCY_MAX];
 141
 142         char *description;
 143         char *fragment_path; /* if loaded from a config file this is the primary path to it */
 144         usec_t fragment_mtime;
 145
 146         /* If there is something to do with this unit, then this is
 147          * the job for it */
 148         Job *job;
 149
 150         dual_timestamp inactive_exit_timestamp;
 151         dual_timestamp active_enter_timestamp;
 152         dual_timestamp active_exit_timestamp;
 153         dual_timestamp inactive_enter_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         /* Refuse manual starting, allow starting only indirectly via dependency. */
 183         bool only_by_dependency;
 184
 185         /* Create default depedencies */
 186         bool default_dependencies;
 187
 188         /* Bring up this unit even if a dependency fails to start */
 189         bool ignore_dependency_failure;
 190
 191         /* When deserializing, temporarily store the job type for this
 192          * unit here, if there was a job scheduled */
 193         int deserialized_job; /* This is actually of type JobType */
 194
 195         bool in_load_queue:1;
 196         bool in_dbus_queue:1;
 197         bool in_cleanup_queue:1;
 198         bool in_gc_queue:1;
 199
 200         bool sent_dbus_new_signal:1;
 201 };
 202
 203 #include "service.h"
 204 #include "timer.h"
 205 #include "socket.h"
 206 #include "target.h"
 207 #include "device.h"
 208 #include "mount.h"
 209 #include "automount.h"
 210 #include "snapshot.h"
 211 #include "swap.h"
 212 #include "path.h"
 213
 214 union Unit {
 215         Meta meta;
 216         Service service;
 217         Timer timer;
 218         Socket socket;
 219         Target target;
 220         Device device;
 221         Mount mount;
 222         Automount automount;
 223         Snapshot snapshot;
 224         Swap swap;
 225         Path path;
 226 };
 227
 228 struct UnitVTable {
 229         const char *suffix;
 230
 231         /* This should reset all type-specific variables. This should
 232          * not allocate memory, and is called with zero-initialized
 233          * data. It should hence only initialize variables that need
 234          * to be set != 0. */
 235         void (*init)(Unit *u);
 236
 237         /* This should free all type-specific variables. It should be
 238          * idempotent. */
 239         void (*done)(Unit *u);
 240
 241         /* Actually load data from disk. This may fail, and should set
 242          * load_state to UNIT_LOADED, UNIT_MERGED or leave it at
 243          * UNIT_STUB if no configuration could be found. */
 244         int (*load)(Unit *u);
 245
 246         /* If a a lot of units got created via enumerate(), this is
 247          * where to actually set the state and call unit_notify(). */
 248         int (*coldplug)(Unit *u);
 249
 250         void (*dump)(Unit *u, FILE *f, const char *prefix);
 251
 252         int (*start)(Unit *u);
 253         int (*stop)(Unit *u);
 254         int (*reload)(Unit *u);
 255
 256         bool (*can_reload)(Unit *u);
 257
 258         /* Write all data that cannot be restored from other sources
 259          * away using unit_serialize_item() */
 260         int (*serialize)(Unit *u, FILE *f, FDSet *fds);
 261
 262         /* Restore one item from the serialization */
 263         int (*deserialize_item)(Unit *u, const char *key, const char *data, FDSet *fds);
 264
 265         /* Boils down the more complex internal state of this unit to
 266          * a simpler one that the engine can understand */
 267         UnitActiveState (*active_state)(Unit *u);
 268
 269         /* Returns the substate specific to this unit type as
 270          * string. This is purely information so that we can give the
 271          * user a more finegrained explanation in which actual state a
 272          * unit is in. */
 273         const char* (*sub_state_to_string)(Unit *u);
 274
 275         /* Return true when there is reason to keep this entry around
 276          * even nothing references it and it isn't active in any
 277          * way */
 278         bool (*check_gc)(Unit *u);
 279
 280         /* Return true when this unit is suitable for snapshotting */
 281         bool (*check_snapshot)(Unit *u);
 282
 283         void (*fd_event)(Unit *u, int fd, uint32_t events, Watch *w);
 284         void (*sigchld_event)(Unit *u, pid_t pid, int code, int status);
 285         void (*timer_event)(Unit *u, uint64_t n_elapsed, Watch *w);
 286
 287         /* Called whenever any of the cgroups this unit watches for
 288          * ran empty */
 289         void (*cgroup_notify_empty)(Unit *u);
 290
 291         /* Called whenever a process of this unit sends us a message */
 292         void (*notify_message)(Unit *u, pid_t pid, char **tags);
 293
 294         /* Called whenever a name thus Unit registered for comes or
 295          * goes away. */
 296         void (*bus_name_owner_change)(Unit *u, const char *name, const char *old_owner, const char *new_owner);
 297
 298         /* Called whenever a bus PID lookup finishes */
 299         void (*bus_query_pid_done)(Unit *u, const char *name, pid_t pid);
 300
 301         /* Called for each message received on the bus */
 302         DBusHandlerResult (*bus_message_handler)(Unit *u, DBusConnection *c, DBusMessage *message);
 303
 304         /* This is called for each unit type and should be used to
 305          * enumerate existing devices and load them. However,
 306          * everything that is loaded here should still stay in
 307          * inactive state. It is the job of the coldplug() call above
 308          * to put the units into the initial state.  */
 309         int (*enumerate)(Manager *m);
 310
 311         /* Type specific cleanups. */
 312         void (*shutdown)(Manager *m);
 313
 314         /* Can units of this type have multiple names? */
 315         bool no_alias:1;
 316
 317         /* If true units of this types can never have "Requires"
 318          * dependencies, because state changes can only be observed,
 319          * not triggered */
 320         bool no_requires:1;
 321
 322         /* Instances make no sense for this type */
 323         bool no_instances:1;
 324
 325         /* Exclude this type from snapshots */
 326         bool no_snapshots:1;
 327
 328         /* Exclude from automatic gc */
 329         bool no_gc:1;
 330
 331         /* Exclude from isolation requests */
 332         bool no_isolate:1;
 333
 334         /* Show status updates on the console */
 335         bool show_status:1;
 336 };
 337
 338 extern const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX];
 339
 340 #define UNIT_VTABLE(u) unit_vtable[(u)->meta.type]
 341
 342 /* For casting a unit into the various unit types */
 343 #define DEFINE_CAST(UPPERCASE, MixedCase)                               \
 344         static inline MixedCase* UPPERCASE(Unit *u) {                   \
 345                 if (_unlikely_(!u || u->meta.type != UNIT_##UPPERCASE)) \
 346                         return NULL;                                    \
 347                                                                         \
 348                 return (MixedCase*) u;                                  \
 349         }
 350
 351 /* For casting the various unit types into a unit */
 352 #define UNIT(u) ((Unit*) (&(u)->meta))
 353
 354 DEFINE_CAST(SOCKET, Socket);
 355 DEFINE_CAST(TIMER, Timer);
 356 DEFINE_CAST(SERVICE, Service);
 357 DEFINE_CAST(TARGET, Target);
 358 DEFINE_CAST(DEVICE, Device);
 359 DEFINE_CAST(MOUNT, Mount);
 360 DEFINE_CAST(AUTOMOUNT, Automount);
 361 DEFINE_CAST(SNAPSHOT, Snapshot);
 362 DEFINE_CAST(SWAP, Swap);
 363 DEFINE_CAST(PATH, Path);
 364
 365 Unit *unit_new(Manager *m);
 366 void unit_free(Unit *u);
 367
 368 int unit_add_name(Unit *u, const char *name);
 369
 370 int unit_add_dependency(Unit *u, UnitDependency d, Unit *other, bool add_reference);
 371 int unit_add_two_dependencies(Unit *u, UnitDependency d, UnitDependency e, Unit *other, bool add_reference);
 372
 373 int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
 374 int unit_add_two_dependencies_by_name(Unit *u, UnitDependency d, UnitDependency e, const char *name, const char *path, bool add_reference);
 375
 376 int unit_add_dependency_by_name_inverse(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
 377 int unit_add_two_dependencies_by_name_inverse(Unit *u, UnitDependency d, UnitDependency e, const char *name, const char *path, bool add_reference);
 378
 379 int unit_add_exec_dependencies(Unit *u, ExecContext *c);
 380
 381 int unit_add_cgroup(Unit *u, CGroupBonding *b);
 382 int unit_add_cgroup_from_text(Unit *u, const char *name);
 383 int unit_add_default_cgroup(Unit *u);
 384 CGroupBonding* unit_get_default_cgroup(Unit *u);
 385
 386 int unit_choose_id(Unit *u, const char *name);
 387 int unit_set_description(Unit *u, const char *description);
 388
 389 bool unit_check_gc(Unit *u);
 390
 391 void unit_add_to_load_queue(Unit *u);
 392 void unit_add_to_dbus_queue(Unit *u);
 393 void unit_add_to_cleanup_queue(Unit *u);
 394 void unit_add_to_gc_queue(Unit *u);
 395
 396 int unit_merge(Unit *u, Unit *other);
 397 int unit_merge_by_name(Unit *u, const char *other);
 398
 399 Unit *unit_follow_merge(Unit *u);
 400
 401 int unit_load_fragment_and_dropin(Unit *u);
 402 int unit_load_fragment_and_dropin_optional(Unit *u);
 403 int unit_load_nop(Unit *u);
 404 int unit_load(Unit *unit);
 405
 406 const char *unit_description(Unit *u);
 407
 408 bool unit_has_name(Unit *u, const char *name);
 409
 410 UnitActiveState unit_active_state(Unit *u);
 411
 412 const char* unit_sub_state_to_string(Unit *u);
 413
 414 void unit_dump(Unit *u, FILE *f, const char *prefix);
 415
 416 bool unit_can_reload(Unit *u);
 417 bool unit_can_start(Unit *u);
 418
 419 int unit_start(Unit *u);
 420 int unit_stop(Unit *u);
 421 int unit_reload(Unit *u);
 422
 423 void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns);
 424
 425 int unit_watch_fd(Unit *u, int fd, uint32_t events, Watch *w);
 426 void unit_unwatch_fd(Unit *u, Watch *w);
 427
 428 int unit_watch_pid(Unit *u, pid_t pid);
 429 void unit_unwatch_pid(Unit *u, pid_t pid);
 430
 431 int unit_watch_timer(Unit *u, usec_t delay, Watch *w);
 432 void unit_unwatch_timer(Unit *u, Watch *w);
 433
 434 int unit_watch_bus_name(Unit *u, const char *name);
 435 void unit_unwatch_bus_name(Unit *u, const char *name);
 436
 437 bool unit_job_is_applicable(Unit *u, JobType j);
 438
 439 int set_unit_path(const char *p);
 440
 441 char *unit_dbus_path(Unit *u);
 442
 443 int unit_load_related_unit(Unit *u, const char *type, Unit **_found);
 444 int unit_get_related_unit(Unit *u, const char *type, Unit **_found);
 445
 446 char *unit_name_printf(Unit *u, const char* text);
 447 char *unit_full_printf(Unit *u, const char *text);
 448 char **unit_full_printf_strv(Unit *u, char **l);
 449
 450 bool unit_can_serialize(Unit *u);
 451 int unit_serialize(Unit *u, FILE *f, FDSet *fds);
 452 void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *value, ...) _printf_attr_(4,5);
 453 void unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value);
 454 int unit_deserialize(Unit *u, FILE *f, FDSet *fds);
 455
 456 int unit_add_node_link(Unit *u, const char *what, bool wants);
 457
 458 int unit_coldplug(Unit *u);
 459
 460 void unit_status_printf(Unit *u, const char *format, ...);
 461
 462 bool unit_need_daemon_reload(Unit *u);
 463
 464 const char *unit_type_to_string(UnitType i);
 465 UnitType unit_type_from_string(const char *s);
 466
 467 const char *unit_load_state_to_string(UnitLoadState i);
 468 UnitLoadState unit_load_state_from_string(const char *s);
 469
 470 const char *unit_active_state_to_string(UnitActiveState i);
 471 UnitActiveState unit_active_state_from_string(const char *s);
 472
 473 const char *unit_dependency_to_string(UnitDependency i);
 474 UnitDependency unit_dependency_from_string(const char *s);
 475
 476 const char *kill_mode_to_string(KillMode k);
 477 KillMode kill_mode_from_string(const char *s);
 478
 479 #endif