src/core/unit.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <stdbool.h>
   5 #include <stdlib.h>
   6 #include <unistd.h>
   7
   8 #include "bpf-program.h"
   9 #include "condition.h"
  10 #include "emergency-action.h"
  11 #include "list.h"
  12 #include "show-status.h"
  13 #include "set.h"
  14 #include "unit-file.h"
  15 #include "cgroup.h"
  16
  17 typedef struct UnitRef UnitRef;
  18
  19 typedef enum KillOperation {
  20         KILL_TERMINATE,
  21         KILL_TERMINATE_AND_LOG,
  22         KILL_RESTART,
  23         KILL_KILL,
  24         KILL_WATCHDOG,
  25         _KILL_OPERATION_MAX,
  26         _KILL_OPERATION_INVALID = -1
  27 } KillOperation;
  28
  29 typedef enum CollectMode {
  30         COLLECT_INACTIVE,
  31         COLLECT_INACTIVE_OR_FAILED,
  32         _COLLECT_MODE_MAX,
  33         _COLLECT_MODE_INVALID = -1,
  34 } CollectMode;
  35
  36 static inline bool UNIT_IS_ACTIVE_OR_RELOADING(UnitActiveState t) {
  37         return IN_SET(t, UNIT_ACTIVE, UNIT_RELOADING);
  38 }
  39
  40 static inline bool UNIT_IS_ACTIVE_OR_ACTIVATING(UnitActiveState t) {
  41         return IN_SET(t, UNIT_ACTIVE, UNIT_ACTIVATING, UNIT_RELOADING);
  42 }
  43
  44 static inline bool UNIT_IS_INACTIVE_OR_DEACTIVATING(UnitActiveState t) {
  45         return IN_SET(t, UNIT_INACTIVE, UNIT_FAILED, UNIT_DEACTIVATING);
  46 }
  47
  48 static inline bool UNIT_IS_INACTIVE_OR_FAILED(UnitActiveState t) {
  49         return IN_SET(t, UNIT_INACTIVE, UNIT_FAILED);
  50 }
  51
  52 static inline bool UNIT_IS_LOAD_COMPLETE(UnitLoadState t) {
  53         return t >= 0 && t < _UNIT_LOAD_STATE_MAX && t != UNIT_STUB && t != UNIT_MERGED;
  54 }
  55
  56 /* Stores the 'reason' a dependency was created as a bit mask, i.e. due to which configuration source it came to be. We
  57  * use this so that we can selectively flush out parts of dependencies again. Note that the same dependency might be
  58  * created as a result of multiple "reasons", hence the bitmask. */
  59 typedef enum UnitDependencyMask {
  60         /* Configured directly by the unit file, .wants/.requires symlink or drop-in, or as an immediate result of a
  61          * non-dependency option configured that way.  */
  62         UNIT_DEPENDENCY_FILE               = 1 << 0,
  63
  64         /* As unconditional implicit dependency (not affected by unit configuration — except by the unit name and
  65          * type) */
  66         UNIT_DEPENDENCY_IMPLICIT           = 1 << 1,
  67
  68         /* A dependency effected by DefaultDependencies=yes. Note that dependencies marked this way are conceptually
  69          * just a subset of UNIT_DEPENDENCY_FILE, as DefaultDependencies= is itself a unit file setting that can only
  70          * be set in unit files. We make this two separate bits only to help debugging how dependencies came to be. */
  71         UNIT_DEPENDENCY_DEFAULT            = 1 << 2,
  72
  73         /* A dependency created from udev rules */
  74         UNIT_DEPENDENCY_UDEV               = 1 << 3,
  75
  76         /* A dependency created because of some unit's RequiresMountsFor= setting */
  77         UNIT_DEPENDENCY_PATH               = 1 << 4,
  78
  79         /* A dependency created because of data read from /proc/self/mountinfo and no other configuration source */
  80         UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT = 1 << 5,
  81
  82         /* A dependency created because of data read from /proc/self/mountinfo, but conditionalized by
  83          * DefaultDependencies= and thus also involving configuration from UNIT_DEPENDENCY_FILE sources */
  84         UNIT_DEPENDENCY_MOUNTINFO_DEFAULT  = 1 << 6,
  85
  86         /* A dependency created because of data read from /proc/swaps and no other configuration source */
  87         UNIT_DEPENDENCY_PROC_SWAP          = 1 << 7,
  88
  89         _UNIT_DEPENDENCY_MASK_FULL         = (1 << 8) - 1,
  90 } UnitDependencyMask;
  91
  92 /* The Unit's dependencies[] hashmaps use this structure as value. It has the same size as a void pointer, and thus can
  93  * be stored directly as hashmap value, without any indirection. Note that this stores two masks, as both the origin
  94  * and the destination of a dependency might have created it. */
  95 typedef union UnitDependencyInfo {
  96         void *data;
  97         struct {
  98                 UnitDependencyMask origin_mask:16;
  99                 UnitDependencyMask destination_mask:16;
 100         } _packed_;
 101 } UnitDependencyInfo;
 102
 103 #include "job.h"
 104
 105 struct UnitRef {
 106         /* Keeps tracks of references to a unit. This is useful so
 107          * that we can merge two units if necessary and correct all
 108          * references to them */
 109
 110         Unit *source, *target;
 111         LIST_FIELDS(UnitRef, refs_by_target);
 112 };
 113
 114 typedef struct Unit {
 115         Manager *manager;
 116
 117         UnitType type;
 118         UnitLoadState load_state;
 119         Unit *merged_into;
 120
 121         FreezerState freezer_state;
 122         sd_bus_message *pending_freezer_message;
 123
 124         char *id;   /* The one special name that we use for identification */
 125         char *instance;
 126
 127         Set *aliases; /* All the other names. */
 128
 129         /* For each dependency type we maintain a Hashmap whose key is the Unit* object, and the value encodes why the
 130          * dependency exists, using the UnitDependencyInfo type */
 131         Hashmap *dependencies[_UNIT_DEPENDENCY_MAX];
 132
 133         /* Similar, for RequiresMountsFor= path dependencies. The key is the path, the value the UnitDependencyInfo type */
 134         Hashmap *requires_mounts_for;
 135
 136         char *description;
 137         char **documentation;
 138
 139         char *fragment_path; /* if loaded from a config file this is the primary path to it */
 140         char *source_path; /* if converted, the source file */
 141         char **dropin_paths;
 142
 143         usec_t fragment_not_found_timestamp_hash;
 144         usec_t fragment_mtime;
 145         usec_t source_mtime;
 146         usec_t dropin_mtime;
 147
 148         /* If this is a transient unit we are currently writing, this is where we are writing it to */
 149         FILE *transient_file;
 150
 151         /* If there is something to do with this unit, then this is the installed job for it */
 152         Job *job;
 153
 154         /* JOB_NOP jobs are special and can be installed without disturbing the real job. */
 155         Job *nop_job;
 156
 157         /* The slot used for watching NameOwnerChanged signals */
 158         sd_bus_slot *match_bus_slot;
 159         sd_bus_slot *get_name_owner_slot;
 160
 161         /* References to this unit from clients */
 162         sd_bus_track *bus_track;
 163         char **deserialized_refs;
 164
 165         /* Job timeout and action to take */
 166         usec_t job_timeout;
 167         usec_t job_running_timeout;
 168         bool job_running_timeout_set:1;
 169         EmergencyAction job_timeout_action;
 170         char *job_timeout_reboot_arg;
 171
 172         /* References to this */
 173         LIST_HEAD(UnitRef, refs_by_target);
 174
 175         /* Conditions to check */
 176         LIST_HEAD(Condition, conditions);
 177         LIST_HEAD(Condition, asserts);
 178
 179         dual_timestamp condition_timestamp;
 180         dual_timestamp assert_timestamp;
 181
 182         /* Updated whenever the low-level state changes */
 183         dual_timestamp state_change_timestamp;
 184
 185         /* Updated whenever the (high-level) active state enters or leaves the active or inactive states */
 186         dual_timestamp inactive_exit_timestamp;
 187         dual_timestamp active_enter_timestamp;
 188         dual_timestamp active_exit_timestamp;
 189         dual_timestamp inactive_enter_timestamp;
 190
 191         UnitRef slice;
 192
 193         /* Per type list */
 194         LIST_FIELDS(Unit, units_by_type);
 195
 196         /* Load queue */
 197         LIST_FIELDS(Unit, load_queue);
 198
 199         /* D-Bus queue */
 200         LIST_FIELDS(Unit, dbus_queue);
 201
 202         /* Cleanup queue */
 203         LIST_FIELDS(Unit, cleanup_queue);
 204
 205         /* GC queue */
 206         LIST_FIELDS(Unit, gc_queue);
 207
 208         /* CGroup realize members queue */
 209         LIST_FIELDS(Unit, cgroup_realize_queue);
 210
 211         /* cgroup empty queue */
 212         LIST_FIELDS(Unit, cgroup_empty_queue);
 213
 214         /* cgroup OOM queue */
 215         LIST_FIELDS(Unit, cgroup_oom_queue);
 216
 217         /* Target dependencies queue */
 218         LIST_FIELDS(Unit, target_deps_queue);
 219
 220         /* Queue of units with StopWhenUnneeded set that shell be checked for clean-up. */
 221         LIST_FIELDS(Unit, stop_when_unneeded_queue);
 222
 223         /* PIDs we keep an eye on. Note that a unit might have many
 224          * more, but these are the ones we care enough about to
 225          * process SIGCHLD for */
 226         Set *pids;
 227
 228         /* Used in SIGCHLD and sd_notify() message event invocation logic to avoid that we dispatch the same event
 229          * multiple times on the same unit. */
 230         unsigned sigchldgen;
 231         unsigned notifygen;
 232
 233         /* Used during GC sweeps */
 234         unsigned gc_marker;
 235
 236         /* Error code when we didn't manage to load the unit (negative) */
 237         int load_error;
 238
 239         /* Put a ratelimit on unit starting */
 240         RateLimit start_ratelimit;
 241         EmergencyAction start_limit_action;
 242
 243         /* What to do on failure or success */
 244         EmergencyAction success_action, failure_action;
 245         int success_action_exit_status, failure_action_exit_status;
 246         char *reboot_arg;
 247
 248         /* Make sure we never enter endless loops with the check unneeded logic, or the BindsTo= logic */
 249         RateLimit auto_stop_ratelimit;
 250
 251         /* Reference to a specific UID/GID */
 252         uid_t ref_uid;
 253         gid_t ref_gid;
 254
 255         /* Cached unit file state and preset */
 256         UnitFileState unit_file_state;
 257         int unit_file_preset;
 258
 259         /* Where the cpu.stat or cpuacct.usage was at the time the unit was started */
 260         nsec_t cpu_usage_base;
 261         nsec_t cpu_usage_last; /* the most recently read value */
 262
 263         /* The current counter of processes sent SIGKILL by systemd-oomd */
 264         uint64_t managed_oom_kill_last;
 265
 266         /* The current counter of the oom_kill field in the memory.events cgroup attribute */
 267         uint64_t oom_kill_last;
 268
 269         /* Where the io.stat data was at the time the unit was started */
 270         uint64_t io_accounting_base[_CGROUP_IO_ACCOUNTING_METRIC_MAX];
 271         uint64_t io_accounting_last[_CGROUP_IO_ACCOUNTING_METRIC_MAX]; /* the most recently read value */
 272
 273         /* Counterparts in the cgroup filesystem */
 274         char *cgroup_path;
 275         CGroupMask cgroup_realized_mask;           /* In which hierarchies does this unit's cgroup exist? (only relevant on cgroup v1) */
 276         CGroupMask cgroup_enabled_mask;            /* Which controllers are enabled (or more correctly: enabled for the children) for this unit's cgroup? (only relevant on cgroup v2) */
 277         CGroupMask cgroup_invalidated_mask;        /* A mask specifying controllers which shall be considered invalidated, and require re-realization */
 278         CGroupMask cgroup_members_mask;            /* A cache for the controllers required by all children of this cgroup (only relevant for slice units) */
 279
 280         /* Inotify watch descriptors for watching cgroup.events and memory.events on cgroupv2 */
 281         int cgroup_control_inotify_wd;
 282         int cgroup_memory_inotify_wd;
 283
 284         /* Device Controller BPF program */
 285         BPFProgram *bpf_device_control_installed;
 286
 287         /* IP BPF Firewalling/accounting */
 288         int ip_accounting_ingress_map_fd;
 289         int ip_accounting_egress_map_fd;
 290
 291         int ipv4_allow_map_fd;
 292         int ipv6_allow_map_fd;
 293         int ipv4_deny_map_fd;
 294         int ipv6_deny_map_fd;
 295
 296         BPFProgram *ip_bpf_ingress, *ip_bpf_ingress_installed;
 297         BPFProgram *ip_bpf_egress, *ip_bpf_egress_installed;
 298         Set *ip_bpf_custom_ingress;
 299         Set *ip_bpf_custom_ingress_installed;
 300         Set *ip_bpf_custom_egress;
 301         Set *ip_bpf_custom_egress_installed;
 302
 303         uint64_t ip_accounting_extra[_CGROUP_IP_ACCOUNTING_METRIC_MAX];
 304
 305         /* Low-priority event source which is used to remove watched PIDs that have gone away, and subscribe to any new
 306          * ones which might have appeared. */
 307         sd_event_source *rewatch_pids_event_source;
 308
 309         /* How to start OnFailure units */
 310         JobMode on_failure_job_mode;
 311
 312         /* Tweaking the GC logic */
 313         CollectMode collect_mode;
 314
 315         /* The current invocation ID */
 316         sd_id128_t invocation_id;
 317         char invocation_id_string[SD_ID128_STRING_MAX]; /* useful when logging */
 318
 319         /* Garbage collect us we nobody wants or requires us anymore */
 320         bool stop_when_unneeded;
 321
 322         /* Create default dependencies */
 323         bool default_dependencies;
 324
 325         /* Refuse manual starting, allow starting only indirectly via dependency. */
 326         bool refuse_manual_start;
 327
 328         /* Don't allow the user to stop this unit manually, allow stopping only indirectly via dependency. */
 329         bool refuse_manual_stop;
 330
 331         /* Allow isolation requests */
 332         bool allow_isolate;
 333
 334         /* Ignore this unit when isolating */
 335         bool ignore_on_isolate;
 336
 337         /* Did the last condition check succeed? */
 338         bool condition_result;
 339         bool assert_result;
 340
 341         /* Is this a transient unit? */
 342         bool transient;
 343
 344         /* Is this a unit that is always running and cannot be stopped? */
 345         bool perpetual;
 346
 347         /* Booleans indicating membership of this unit in the various queues */
 348         bool in_load_queue:1;
 349         bool in_dbus_queue:1;
 350         bool in_cleanup_queue:1;
 351         bool in_gc_queue:1;
 352         bool in_cgroup_realize_queue:1;
 353         bool in_cgroup_empty_queue:1;
 354         bool in_cgroup_oom_queue:1;
 355         bool in_target_deps_queue:1;
 356         bool in_stop_when_unneeded_queue:1;
 357
 358         bool sent_dbus_new_signal:1;
 359
 360         bool in_audit:1;
 361         bool on_console:1;
 362
 363         bool cgroup_realized:1;
 364         bool cgroup_members_mask_valid:1;
 365
 366         /* Reset cgroup accounting next time we fork something off */
 367         bool reset_accounting:1;
 368
 369         bool start_limit_hit:1;
 370
 371         /* Did we already invoke unit_coldplug() for this unit? */
 372         bool coldplugged:1;
 373
 374         /* For transient units: whether to add a bus track reference after creating the unit */
 375         bool bus_track_add:1;
 376
 377         /* Remember which unit state files we created */
 378         bool exported_invocation_id:1;
 379         bool exported_log_level_max:1;
 380         bool exported_log_extra_fields:1;
 381         bool exported_log_ratelimit_interval:1;
 382         bool exported_log_ratelimit_burst:1;
 383
 384         /* Whether we warned about clamping the CPU quota period */
 385         bool warned_clamping_cpu_quota_period:1;
 386
 387         /* When writing transient unit files, stores which section we stored last. If < 0, we didn't write any yet. If
 388          * == 0 we are in the [Unit] section, if > 0 we are in the unit type-specific section. */
 389         signed int last_section_private:2;
 390 } Unit;
 391
 392 typedef struct UnitStatusMessageFormats {
 393         const char *starting_stopping[2];
 394         const char *finished_start_job[_JOB_RESULT_MAX];
 395         const char *finished_stop_job[_JOB_RESULT_MAX];
 396         /* If this entry is present, it'll be called to provide a context-dependent format string,
 397          * or NULL to fall back to finished_{start,stop}_job; if those are NULL too, fall back to generic. */
 398         const char *(*finished_job)(Unit *u, JobType t, JobResult result);
 399 } UnitStatusMessageFormats;
 400
 401 /* Flags used when writing drop-in files or transient unit files */
 402 typedef enum UnitWriteFlags {
 403         /* Write a runtime unit file or drop-in (i.e. one below /run) */
 404         UNIT_RUNTIME           = 1 << 0,
 405
 406         /* Write a persistent drop-in (i.e. one below /etc) */
 407         UNIT_PERSISTENT        = 1 << 1,
 408
 409         /* Place this item in the per-unit-type private section, instead of [Unit] */
 410         UNIT_PRIVATE           = 1 << 2,
 411
 412         /* Apply specifier escaping before writing */
 413         UNIT_ESCAPE_SPECIFIERS = 1 << 3,
 414
 415         /* Apply C escaping before writing */
 416         UNIT_ESCAPE_C          = 1 << 4,
 417 } UnitWriteFlags;
 418
 419 /* Returns true if neither persistent, nor runtime storage is requested, i.e. this is a check invocation only */
 420 static inline bool UNIT_WRITE_FLAGS_NOOP(UnitWriteFlags flags) {
 421         return (flags & (UNIT_RUNTIME|UNIT_PERSISTENT)) == 0;
 422 }
 423
 424 #include "kill.h"
 425
 426 typedef struct UnitVTable {
 427         /* How much memory does an object of this unit type need */
 428         size_t object_size;
 429
 430         /* If greater than 0, the offset into the object where
 431          * ExecContext is found, if the unit type has that */
 432         size_t exec_context_offset;
 433
 434         /* If greater than 0, the offset into the object where
 435          * CGroupContext is found, if the unit type has that */
 436         size_t cgroup_context_offset;
 437
 438         /* If greater than 0, the offset into the object where
 439          * KillContext is found, if the unit type has that */
 440         size_t kill_context_offset;
 441
 442         /* If greater than 0, the offset into the object where the
 443          * pointer to ExecRuntime is found, if the unit type has
 444          * that */
 445         size_t exec_runtime_offset;
 446
 447         /* If greater than 0, the offset into the object where the pointer to DynamicCreds is found, if the unit type
 448          * has that. */
 449         size_t dynamic_creds_offset;
 450
 451         /* The name of the configuration file section with the private settings of this unit */
 452         const char *private_section;
 453
 454         /* Config file sections this unit type understands, separated
 455          * by NUL chars */
 456         const char *sections;
 457
 458         /* This should reset all type-specific variables. This should
 459          * not allocate memory, and is called with zero-initialized
 460          * data. It should hence only initialize variables that need
 461          * to be set != 0. */
 462         void (*init)(Unit *u);
 463
 464         /* This should free all type-specific variables. It should be
 465          * idempotent. */
 466         void (*done)(Unit *u);
 467
 468         /* Actually load data from disk. This may fail, and should set
 469          * load_state to UNIT_LOADED, UNIT_MERGED or leave it at
 470          * UNIT_STUB if no configuration could be found. */
 471         int (*load)(Unit *u);
 472
 473         /* During deserialization we only record the intended state to return to. With coldplug() we actually put the
 474          * deserialized state in effect. This is where unit_notify() should be called to start things up. Note that
 475          * this callback is invoked *before* we leave the reloading state of the manager, i.e. *before* we consider the
 476          * reloading to be complete. Thus, this callback should just restore the exact same state for any unit that was
 477          * in effect before the reload, i.e. units should not catch up with changes happened during the reload. That's
 478          * what catchup() below is for. */
 479         int (*coldplug)(Unit *u);
 480
 481         /* This is called shortly after all units' coldplug() call was invoked, and *after* the manager left the
 482          * reloading state. It's supposed to catch up with state changes due to external events we missed so far (for
 483          * example because they took place while we were reloading/reexecing) */
 484         void (*catchup)(Unit *u);
 485
 486         void (*dump)(Unit *u, FILE *f, const char *prefix);
 487
 488         int (*start)(Unit *u);
 489         int (*stop)(Unit *u);
 490         int (*reload)(Unit *u);
 491
 492         int (*kill)(Unit *u, KillWho w, int signo, sd_bus_error *error);
 493
 494         /* Clear out the various runtime/state/cache/logs/configuration data */
 495         int (*clean)(Unit *u, ExecCleanMask m);
 496
 497         /* Freeze the unit */
 498         int (*freeze)(Unit *u);
 499         int (*thaw)(Unit *u);
 500         bool (*can_freeze)(Unit *u);
 501
 502         /* Return which kind of data can be cleaned */
 503         int (*can_clean)(Unit *u, ExecCleanMask *ret);
 504
 505         bool (*can_reload)(Unit *u);
 506
 507         /* Write all data that cannot be restored from other sources
 508          * away using unit_serialize_item() */
 509         int (*serialize)(Unit *u, FILE *f, FDSet *fds);
 510
 511         /* Restore one item from the serialization */
 512         int (*deserialize_item)(Unit *u, const char *key, const char *data, FDSet *fds);
 513
 514         /* Try to match up fds with what we need for this unit */
 515         void (*distribute_fds)(Unit *u, FDSet *fds);
 516
 517         /* Boils down the more complex internal state of this unit to
 518          * a simpler one that the engine can understand */
 519         UnitActiveState (*active_state)(Unit *u);
 520
 521         /* Returns the substate specific to this unit type as
 522          * string. This is purely information so that we can give the
 523          * user a more fine grained explanation in which actual state a
 524          * unit is in. */
 525         const char* (*sub_state_to_string)(Unit *u);
 526
 527         /* Additionally to UnitActiveState determine whether unit is to be restarted. */
 528         bool (*will_restart)(Unit *u);
 529
 530         /* Return false when there is a reason to prevent this unit from being gc'ed
 531          * even though nothing references it and it isn't active in any way. */
 532         bool (*may_gc)(Unit *u);
 533
 534         /* Return true when the unit is not controlled by the manager (e.g. extrinsic mounts). */
 535         bool (*is_extrinsic)(Unit *u);
 536
 537         /* When the unit is not running and no job for it queued we shall release its runtime resources */
 538         void (*release_resources)(Unit *u);
 539
 540         /* Invoked on every child that died */
 541         void (*sigchld_event)(Unit *u, pid_t pid, int code, int status);
 542
 543         /* Reset failed state if we are in failed state */
 544         void (*reset_failed)(Unit *u);
 545
 546         /* Called whenever any of the cgroups this unit watches for ran empty */
 547         void (*notify_cgroup_empty)(Unit *u);
 548
 549         /* Called whenever an OOM kill event on this unit was seen */
 550         void (*notify_cgroup_oom)(Unit *u);
 551
 552         /* Called whenever a process of this unit sends us a message */
 553         void (*notify_message)(Unit *u, const struct ucred *ucred, char * const *tags, FDSet *fds);
 554
 555         /* Called whenever a name this Unit registered for comes or goes away. */
 556         void (*bus_name_owner_change)(Unit *u, const char *new_owner);
 557
 558         /* Called for each property that is being set */
 559         int (*bus_set_property)(Unit *u, const char *name, sd_bus_message *message, UnitWriteFlags flags, sd_bus_error *error);
 560
 561         /* Called after at least one property got changed to apply the necessary change */
 562         int (*bus_commit_properties)(Unit *u);
 563
 564         /* Return the unit this unit is following */
 565         Unit *(*following)(Unit *u);
 566
 567         /* Return the set of units that are following each other */
 568         int (*following_set)(Unit *u, Set **s);
 569
 570         /* Invoked each time a unit this unit is triggering changes
 571          * state or gains/loses a job */
 572         void (*trigger_notify)(Unit *u, Unit *trigger);
 573
 574         /* Called whenever CLOCK_REALTIME made a jump */
 575         void (*time_change)(Unit *u);
 576
 577         /* Called whenever /etc/localtime was modified */
 578         void (*timezone_change)(Unit *u);
 579
 580         /* Returns the next timeout of a unit */
 581         int (*get_timeout)(Unit *u, usec_t *timeout);
 582
 583         /* Returns the main PID if there is any defined, or 0. */
 584         pid_t (*main_pid)(Unit *u);
 585
 586         /* Returns the main PID if there is any defined, or 0. */
 587         pid_t (*control_pid)(Unit *u);
 588
 589         /* Returns true if the unit currently needs access to the console */
 590         bool (*needs_console)(Unit *u);
 591
 592         /* Returns the exit status to propagate in case of FailureAction=exit/SuccessAction=exit; usually returns the
 593          * exit code of the "main" process of the service or similar. */
 594         int (*exit_status)(Unit *u);
 595
 596         /* Like the enumerate() callback further down, but only enumerates the perpetual units, i.e. all units that
 597          * unconditionally exist and are always active. The main reason to keep both enumeration functions separate is
 598          * philosophical: the state of perpetual units should be put in place by coldplug(), while the state of those
 599          * discovered through regular enumeration should be put in place by catchup(), see below. */
 600         void (*enumerate_perpetual)(Manager *m);
 601
 602         /* This is called for each unit type and should be used to enumerate units already existing in the system
 603          * internally and load them. However, everything that is loaded here should still stay in inactive state. It is
 604          * the job of the catchup() call above to put the units into the discovered state. */
 605         void (*enumerate)(Manager *m);
 606
 607         /* Type specific cleanups. */
 608         void (*shutdown)(Manager *m);
 609
 610         /* If this function is set and return false all jobs for units
 611          * of this type will immediately fail. */
 612         bool (*supported)(void);
 613
 614         /* The strings to print in status messages */
 615         UnitStatusMessageFormats status_message_formats;
 616
 617         /* True if transient units of this type are OK */
 618         bool can_transient:1;
 619
 620         /* True if cgroup delegation is permissible */
 621         bool can_delegate:1;
 622
 623         /* True if the unit type triggers other units, i.e. can have a UNIT_TRIGGERS dependency */
 624         bool can_trigger:1;
 625
 626         /* True if the unit type knows a failure state, and thus can be source of an OnFailure= dependency */
 627         bool can_fail:1;
 628
 629         /* True if units of this type shall be startable only once and then never again */
 630         bool once_only:1;
 631
 632         /* True if queued jobs of this type should be GC'ed if no other job needs them anymore */
 633         bool gc_jobs:1;
 634
 635         /* True if systemd-oomd can monitor and act on this unit's recursive children's cgroup(s)  */
 636         bool can_set_managed_oom:1;
 637 } UnitVTable;
 638
 639 extern const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX];
 640
 641 static inline const UnitVTable* UNIT_VTABLE(Unit *u) {
 642         return unit_vtable[u->type];
 643 }
 644
 645 /* For casting a unit into the various unit types */
 646 #define DEFINE_CAST(UPPERCASE, MixedCase)                               \
 647         static inline MixedCase* UPPERCASE(Unit *u) {                   \
 648                 if (_unlikely_(!u || u->type != UNIT_##UPPERCASE))      \
 649                         return NULL;                                    \
 650                                                                         \
 651                 return (MixedCase*) u;                                  \
 652         }
 653
 654 /* For casting the various unit types into a unit */
 655 #define UNIT(u)                                         \
 656         ({                                              \
 657                 typeof(u) _u_ = (u);                    \
 658                 Unit *_w_ = _u_ ? &(_u_)->meta : NULL;  \
 659                 _w_;                                    \
 660         })
 661
 662 #define UNIT_HAS_EXEC_CONTEXT(u) (UNIT_VTABLE(u)->exec_context_offset > 0)
 663 #define UNIT_HAS_CGROUP_CONTEXT(u) (UNIT_VTABLE(u)->cgroup_context_offset > 0)
 664 #define UNIT_HAS_KILL_CONTEXT(u) (UNIT_VTABLE(u)->kill_context_offset > 0)
 665
 666 static inline Unit* UNIT_TRIGGER(Unit *u) {
 667         return hashmap_first_key(u->dependencies[UNIT_TRIGGERS]);
 668 }
 669
 670 Unit *unit_new(Manager *m, size_t size);
 671 void unit_free(Unit *u);
 672 DEFINE_TRIVIAL_CLEANUP_FUNC(Unit *, unit_free);
 673
 674 int unit_new_for_name(Manager *m, size_t size, const char *name, Unit **ret);
 675 int unit_add_name(Unit *u, const char *name);
 676
 677 int unit_add_dependency(Unit *u, UnitDependency d, Unit *other, bool add_reference, UnitDependencyMask mask);
 678 int unit_add_two_dependencies(Unit *u, UnitDependency d, UnitDependency e, Unit *other, bool add_reference, UnitDependencyMask mask);
 679
 680 int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, bool add_reference, UnitDependencyMask mask);
 681 int unit_add_two_dependencies_by_name(Unit *u, UnitDependency d, UnitDependency e, const char *name, bool add_reference, UnitDependencyMask mask);
 682
 683 int unit_add_exec_dependencies(Unit *u, ExecContext *c);
 684
 685 int unit_choose_id(Unit *u, const char *name);
 686 int unit_set_description(Unit *u, const char *description);
 687
 688 bool unit_may_gc(Unit *u);
 689
 690 static inline bool unit_is_extrinsic(Unit *u) {
 691         return u->perpetual ||
 692                 (UNIT_VTABLE(u)->is_extrinsic && UNIT_VTABLE(u)->is_extrinsic(u));
 693 }
 694
 695 void unit_add_to_load_queue(Unit *u);
 696 void unit_add_to_dbus_queue(Unit *u);
 697 void unit_add_to_cleanup_queue(Unit *u);
 698 void unit_add_to_gc_queue(Unit *u);
 699 void unit_add_to_target_deps_queue(Unit *u);
 700 void unit_submit_to_stop_when_unneeded_queue(Unit *u);
 701
 702 int unit_merge(Unit *u, Unit *other);
 703 int unit_merge_by_name(Unit *u, const char *other);
 704
 705 Unit *unit_follow_merge(Unit *u) _pure_;
 706
 707 int unit_load_fragment_and_dropin(Unit *u, bool fragment_required);
 708 int unit_load(Unit *unit);
 709
 710 int unit_set_slice(Unit *u, Unit *slice);
 711 int unit_set_default_slice(Unit *u);
 712
 713 const char *unit_description(Unit *u) _pure_;
 714 const char *unit_status_string(Unit *u) _pure_;
 715
 716 bool unit_has_name(const Unit *u, const char *name);
 717
 718 UnitActiveState unit_active_state(Unit *u);
 719 FreezerState unit_freezer_state(Unit *u);
 720 int unit_freezer_state_kernel(Unit *u, FreezerState *ret);
 721
 722 const char* unit_sub_state_to_string(Unit *u);
 723
 724 void unit_dump(Unit *u, FILE *f, const char *prefix);
 725
 726 bool unit_can_reload(Unit *u) _pure_;
 727 bool unit_can_start(Unit *u) _pure_;
 728 bool unit_can_stop(Unit *u) _pure_;
 729 bool unit_can_isolate(Unit *u) _pure_;
 730
 731 int unit_start(Unit *u);
 732 int unit_stop(Unit *u);
 733 int unit_reload(Unit *u);
 734
 735 int unit_kill(Unit *u, KillWho w, int signo, sd_bus_error *error);
 736 int unit_kill_common(Unit *u, KillWho who, int signo, pid_t main_pid, pid_t control_pid, sd_bus_error *error);
 737
 738 typedef enum UnitNotifyFlags {
 739         UNIT_NOTIFY_RELOAD_FAILURE    = 1 << 0,
 740         UNIT_NOTIFY_WILL_AUTO_RESTART = 1 << 1,
 741         UNIT_NOTIFY_SKIP_CONDITION    = 1 << 2,
 742 } UnitNotifyFlags;
 743
 744 void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, UnitNotifyFlags flags);
 745
 746 int unit_watch_pid(Unit *u, pid_t pid, bool exclusive);
 747 void unit_unwatch_pid(Unit *u, pid_t pid);
 748 void unit_unwatch_all_pids(Unit *u);
 749
 750 int unit_enqueue_rewatch_pids(Unit *u);
 751 void unit_dequeue_rewatch_pids(Unit *u);
 752
 753 int unit_install_bus_match(Unit *u, sd_bus *bus, const char *name);
 754 int unit_watch_bus_name(Unit *u, const char *name);
 755 void unit_unwatch_bus_name(Unit *u, const char *name);
 756
 757 bool unit_job_is_applicable(Unit *u, JobType j);
 758
 759 int set_unit_path(const char *p);
 760
 761 char *unit_dbus_path(Unit *u);
 762 char *unit_dbus_path_invocation_id(Unit *u);
 763
 764 int unit_load_related_unit(Unit *u, const char *type, Unit **_found);
 765
 766 bool unit_can_serialize(Unit *u) _pure_;
 767
 768 int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs);
 769 int unit_deserialize(Unit *u, FILE *f, FDSet *fds);
 770 int unit_deserialize_skip(FILE *f);
 771
 772 int unit_add_node_dependency(Unit *u, const char *what, UnitDependency d, UnitDependencyMask mask);
 773 int unit_add_blockdev_dependency(Unit *u, const char *what, UnitDependencyMask mask);
 774
 775 int unit_coldplug(Unit *u);
 776 void unit_catchup(Unit *u);
 777
 778 void unit_status_printf(Unit *u, StatusType status_type, const char *status, const char *unit_status_msg_format) _printf_(4, 0);
 779
 780 bool unit_need_daemon_reload(Unit *u);
 781
 782 void unit_reset_failed(Unit *u);
 783
 784 Unit *unit_following(Unit *u);
 785 int unit_following_set(Unit *u, Set **s);
 786
 787 const char *unit_slice_name(Unit *u);
 788
 789 bool unit_stop_pending(Unit *u) _pure_;
 790 bool unit_inactive_or_pending(Unit *u) _pure_;
 791 bool unit_active_or_pending(Unit *u);
 792 bool unit_will_restart_default(Unit *u);
 793 bool unit_will_restart(Unit *u);
 794
 795 int unit_add_default_target_dependency(Unit *u, Unit *target);
 796
 797 void unit_start_on_failure(Unit *u);
 798 void unit_trigger_notify(Unit *u);
 799
 800 UnitFileState unit_get_unit_file_state(Unit *u);
 801 int unit_get_unit_file_preset(Unit *u);
 802
 803 Unit* unit_ref_set(UnitRef *ref, Unit *source, Unit *target);
 804 void unit_ref_unset(UnitRef *ref);
 805
 806 #define UNIT_DEREF(ref) ((ref).target)
 807 #define UNIT_ISSET(ref) (!!(ref).target)
 808
 809 int unit_patch_contexts(Unit *u);
 810
 811 ExecContext *unit_get_exec_context(Unit *u) _pure_;
 812 KillContext *unit_get_kill_context(Unit *u) _pure_;
 813 CGroupContext *unit_get_cgroup_context(Unit *u) _pure_;
 814
 815 ExecRuntime *unit_get_exec_runtime(Unit *u) _pure_;
 816
 817 int unit_setup_exec_runtime(Unit *u);
 818 int unit_setup_dynamic_creds(Unit *u);
 819
 820 char* unit_escape_setting(const char *s, UnitWriteFlags flags, char **buf);
 821 char* unit_concat_strv(char **l, UnitWriteFlags flags);
 822
 823 int unit_write_setting(Unit *u, UnitWriteFlags flags, const char *name, const char *data);
 824 int unit_write_settingf(Unit *u, UnitWriteFlags mode, const char *name, const char *format, ...) _printf_(4,5);
 825
 826 int unit_kill_context(Unit *u, KillContext *c, KillOperation k, pid_t main_pid, pid_t control_pid, bool main_pid_alien);
 827
 828 int unit_make_transient(Unit *u);
 829
 830 int unit_require_mounts_for(Unit *u, const char *path, UnitDependencyMask mask);
 831
 832 bool unit_type_supported(UnitType t);
 833
 834 bool unit_is_pristine(Unit *u);
 835
 836 bool unit_is_unneeded(Unit *u);
 837
 838 pid_t unit_control_pid(Unit *u);
 839 pid_t unit_main_pid(Unit *u);
 840
 841 void unit_warn_if_dir_nonempty(Unit *u, const char* where);
 842 int unit_fail_if_noncanonical(Unit *u, const char* where);
 843
 844 int unit_test_start_limit(Unit *u);
 845
 846 int unit_ref_uid_gid(Unit *u, uid_t uid, gid_t gid);
 847 void unit_unref_uid_gid(Unit *u, bool destroy_now);
 848
 849 void unit_notify_user_lookup(Unit *u, uid_t uid, gid_t gid);
 850
 851 int unit_acquire_invocation_id(Unit *u);
 852
 853 bool unit_shall_confirm_spawn(Unit *u);
 854
 855 int unit_set_exec_params(Unit *s, ExecParameters *p);
 856
 857 int unit_fork_helper_process(Unit *u, const char *name, pid_t *ret);
 858 int unit_fork_and_watch_rm_rf(Unit *u, char **paths, pid_t *ret_pid);
 859
 860 void unit_remove_dependencies(Unit *u, UnitDependencyMask mask);
 861
 862 void unit_export_state_files(Unit *u);
 863 void unit_unlink_state_files(Unit *u);
 864
 865 int unit_prepare_exec(Unit *u);
 866
 867 int unit_log_leftover_process_start(pid_t pid, int sig, void *userdata);
 868 int unit_log_leftover_process_stop(pid_t pid, int sig, void *userdata);
 869 int unit_warn_leftover_processes(Unit *u, cg_kill_log_func_t log_func);
 870
 871 bool unit_needs_console(Unit *u);
 872
 873 const char *unit_label_path(const Unit *u);
 874
 875 int unit_pid_attachable(Unit *unit, pid_t pid, sd_bus_error *error);
 876
 877 static inline bool unit_has_job_type(Unit *u, JobType type) {
 878         return u && u->job && u->job->type == type;
 879 }
 880
 881 /* unit_log_skip is for cases like ExecCondition= where a unit is considered "done"
 882  * after some execution, rather than succeeded or failed. */
 883 void unit_log_skip(Unit *u, const char *result);
 884 void unit_log_success(Unit *u);
 885 void unit_log_failure(Unit *u, const char *result);
 886 static inline void unit_log_result(Unit *u, bool success, const char *result) {
 887         if (success)
 888                 unit_log_success(u);
 889         else
 890                 unit_log_failure(u, result);
 891 }
 892
 893 void unit_log_process_exit(Unit *u, const char *kind, const char *command, bool success, int code, int status);
 894
 895 int unit_exit_status(Unit *u);
 896 int unit_success_action_exit_status(Unit *u);
 897 int unit_failure_action_exit_status(Unit *u);
 898
 899 int unit_test_trigger_loaded(Unit *u);
 900
 901 void unit_destroy_runtime_data(Unit *u, const ExecContext *context);
 902 int unit_clean(Unit *u, ExecCleanMask mask);
 903 int unit_can_clean(Unit *u, ExecCleanMask *ret_mask);
 904
 905 bool unit_can_freeze(Unit *u);
 906 int unit_freeze(Unit *u);
 907 void unit_frozen(Unit *u);
 908
 909 int unit_thaw(Unit *u);
 910 void unit_thawed(Unit *u);
 911
 912 int unit_freeze_vtable_common(Unit *u);
 913 int unit_thaw_vtable_common(Unit *u);
 914
 915 /* Macros which append UNIT= or USER_UNIT= to the message */
 916
 917 #define log_unit_full_errno(unit, level, error, ...)                    \
 918         ({                                                              \
 919                 const Unit *_u = (unit);                                \
 920                 (log_get_max_level() < LOG_PRI(level)) ? -ERRNO_VALUE(error) : \
 921                         _u ? log_object_internal(level, error, PROJECT_FILE, __LINE__, __func__, _u->manager->unit_log_field, _u->id, _u->manager->invocation_log_field, _u->invocation_id_string, ##__VA_ARGS__) : \
 922                                 log_internal(level, error, PROJECT_FILE, __LINE__, __func__, ##__VA_ARGS__); \
 923         })
 924
 925 #define log_unit_full(unit, level, ...) (void) log_unit_full_errno(unit, level, 0, __VA_ARGS__)
 926
 927 #define log_unit_debug(unit, ...)   log_unit_full_errno(unit, LOG_DEBUG, 0, __VA_ARGS__)
 928 #define log_unit_info(unit, ...)    log_unit_full(unit, LOG_INFO, __VA_ARGS__)
 929 #define log_unit_notice(unit, ...)  log_unit_full(unit, LOG_NOTICE, __VA_ARGS__)
 930 #define log_unit_warning(unit, ...) log_unit_full(unit, LOG_WARNING, __VA_ARGS__)
 931 #define log_unit_error(unit, ...)   log_unit_full(unit, LOG_ERR, __VA_ARGS__)
 932
 933 #define log_unit_debug_errno(unit, error, ...)   log_unit_full_errno(unit, LOG_DEBUG, error, __VA_ARGS__)
 934 #define log_unit_info_errno(unit, error, ...)    log_unit_full_errno(unit, LOG_INFO, error, __VA_ARGS__)
 935 #define log_unit_notice_errno(unit, error, ...)  log_unit_full_errno(unit, LOG_NOTICE, error, __VA_ARGS__)
 936 #define log_unit_warning_errno(unit, error, ...) log_unit_full_errno(unit, LOG_WARNING, error, __VA_ARGS__)
 937 #define log_unit_error_errno(unit, error, ...)   log_unit_full_errno(unit, LOG_ERR, error, __VA_ARGS__)
 938
 939 #define LOG_UNIT_MESSAGE(unit, fmt, ...) "MESSAGE=%s: " fmt, (unit)->id, ##__VA_ARGS__
 940 #define LOG_UNIT_ID(unit) (unit)->manager->unit_log_format_string, (unit)->id
 941 #define LOG_UNIT_INVOCATION_ID(unit) (unit)->manager->invocation_log_format_string, (unit)->invocation_id_string
 942
 943 const char* collect_mode_to_string(CollectMode m) _const_;
 944 CollectMode collect_mode_from_string(const char *s) _pure_;