src/core/job.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   This file is part of systemd.
   6
   7   Copyright 2010 Lennart Poettering
   8 ***/
   9
  10 #include <stdbool.h>
  11
  12 #include "sd-event.h"
  13
  14 #include "list.h"
  15 #include "unit-name.h"
  16
  17 typedef struct Job Job;
  18 typedef struct JobDependency JobDependency;
  19 typedef enum JobType JobType;
  20 typedef enum JobState JobState;
  21 typedef enum JobMode JobMode;
  22 typedef enum JobResult JobResult;
  23
  24 /* Be careful when changing the job types! Adjust job_merging_table[] accordingly! */
  25 enum JobType {
  26         JOB_START,                  /* if a unit does not support being started, we'll just wait until it becomes active */
  27         JOB_VERIFY_ACTIVE,
  28
  29         JOB_STOP,
  30
  31         JOB_RELOAD,                 /* if running, reload */
  32
  33         /* Note that restarts are first treated like JOB_STOP, but
  34          * then instead of finishing are patched to become
  35          * JOB_START. */
  36         JOB_RESTART,                /* If running, stop. Then start unconditionally. */
  37
  38         _JOB_TYPE_MAX_MERGING,
  39
  40         /* JOB_NOP can enter into a transaction, but as it won't pull in
  41          * any dependencies and it uses the special 'nop_job' slot in Unit,
  42          * it won't have to merge with anything (except possibly into another
  43          * JOB_NOP, previously installed). JOB_NOP is special-cased in
  44          * job_type_is_*() functions so that the transaction can be
  45          * activated. */
  46         JOB_NOP = _JOB_TYPE_MAX_MERGING, /* do nothing */
  47
  48         _JOB_TYPE_MAX_IN_TRANSACTION,
  49
  50         /* JOB_TRY_RESTART can never appear in a transaction, because
  51          * it always collapses into JOB_RESTART or JOB_NOP before entering.
  52          * Thus we never need to merge it with anything. */
  53         JOB_TRY_RESTART = _JOB_TYPE_MAX_IN_TRANSACTION, /* if running, stop and then start */
  54
  55         /* Similar to JOB_TRY_RESTART but collapses to JOB_RELOAD or JOB_NOP */
  56         JOB_TRY_RELOAD,
  57
  58         /* JOB_RELOAD_OR_START won't enter into a transaction and cannot result
  59          * from transaction merging (there's no way for JOB_RELOAD and
  60          * JOB_START to meet in one transaction). It can result from a merge
  61          * during job installation, but then it will immediately collapse into
  62          * one of the two simpler types. */
  63         JOB_RELOAD_OR_START,        /* if running, reload, otherwise start */
  64
  65         _JOB_TYPE_MAX,
  66         _JOB_TYPE_INVALID = -1
  67 };
  68
  69 enum JobState {
  70         JOB_WAITING,
  71         JOB_RUNNING,
  72         _JOB_STATE_MAX,
  73         _JOB_STATE_INVALID = -1
  74 };
  75
  76 enum JobMode {
  77         JOB_FAIL,                /* Fail if a conflicting job is already queued */
  78         JOB_REPLACE,             /* Replace an existing conflicting job */
  79         JOB_REPLACE_IRREVERSIBLY,/* Like JOB_REPLACE + produce irreversible jobs */
  80         JOB_ISOLATE,             /* Start a unit, and stop all others */
  81         JOB_FLUSH,               /* Flush out all other queued jobs when queing this one */
  82         JOB_IGNORE_DEPENDENCIES, /* Ignore both requirement and ordering dependencies */
  83         JOB_IGNORE_REQUIREMENTS, /* Ignore requirement dependencies */
  84         _JOB_MODE_MAX,
  85         _JOB_MODE_INVALID = -1
  86 };
  87
  88 enum JobResult {
  89         JOB_DONE,                /* Job completed successfully */
  90         JOB_CANCELED,            /* Job canceled by a conflicting job installation or by explicit cancel request */
  91         JOB_TIMEOUT,             /* Job timeout elapsed */
  92         JOB_FAILED,              /* Job failed */
  93         JOB_DEPENDENCY,          /* A required dependency job did not result in JOB_DONE */
  94         JOB_SKIPPED,             /* Negative result of JOB_VERIFY_ACTIVE */
  95         JOB_INVALID,             /* JOB_RELOAD of inactive unit */
  96         JOB_ASSERT,              /* Couldn't start a unit, because an assert didn't hold */
  97         JOB_UNSUPPORTED,         /* Couldn't start a unit, because the unit type is not supported on the system */
  98         JOB_COLLECTED,           /* Job was garbage collected, since nothing needed it anymore */
  99         JOB_ONCE,                /* Unit was started before, and hence can't be started again */
 100         _JOB_RESULT_MAX,
 101         _JOB_RESULT_INVALID = -1
 102 };
 103
 104 #include "unit.h"
 105
 106 struct JobDependency {
 107         /* Encodes that the 'subject' job needs the 'object' job in
 108          * some way. This structure is used only while building a transaction. */
 109         Job *subject;
 110         Job *object;
 111
 112         LIST_FIELDS(JobDependency, subject);
 113         LIST_FIELDS(JobDependency, object);
 114
 115         bool matters:1;
 116         bool conflicts:1;
 117 };
 118
 119 struct Job {
 120         Manager *manager;
 121         Unit *unit;
 122
 123         LIST_FIELDS(Job, transaction);
 124         LIST_FIELDS(Job, run_queue);
 125         LIST_FIELDS(Job, dbus_queue);
 126         LIST_FIELDS(Job, gc_queue);
 127
 128         LIST_HEAD(JobDependency, subject_list);
 129         LIST_HEAD(JobDependency, object_list);
 130
 131         /* Used for graph algs as a "I have been here" marker */
 132         Job* marker;
 133         unsigned generation;
 134
 135         uint32_t id;
 136
 137         JobType type;
 138         JobState state;
 139
 140         sd_event_source *timer_event_source;
 141         usec_t begin_usec;
 142         usec_t begin_running_usec;
 143
 144         /*
 145          * This tracks where to send signals, and also which clients
 146          * are allowed to call DBus methods on the job (other than
 147          * root).
 148          *
 149          * There can be more than one client, because of job merging.
 150          */
 151         sd_bus_track *bus_track;
 152         char **deserialized_clients;
 153
 154         JobResult result;
 155
 156         bool installed:1;
 157         bool in_run_queue:1;
 158         bool matters_to_anchor:1;
 159         bool in_dbus_queue:1;
 160         bool sent_dbus_new_signal:1;
 161         bool ignore_order:1;
 162         bool irreversible:1;
 163         bool in_gc_queue:1;
 164         bool ref_by_private_bus:1;
 165 };
 166
 167 Job* job_new(Unit *unit, JobType type);
 168 Job* job_new_raw(Unit *unit);
 169 void job_free(Job *job);
 170 Job* job_install(Job *j);
 171 int job_install_deserialized(Job *j);
 172 void job_uninstall(Job *j);
 173 void job_dump(Job *j, FILE*f, const char *prefix);
 174 int job_serialize(Job *j, FILE *f);
 175 int job_deserialize(Job *j, FILE *f);
 176 int job_coldplug(Job *j);
 177
 178 JobDependency* job_dependency_new(Job *subject, Job *object, bool matters, bool conflicts);
 179 void job_dependency_free(JobDependency *l);
 180
 181 int job_merge(Job *j, Job *other);
 182
 183 JobType job_type_lookup_merge(JobType a, JobType b) _pure_;
 184
 185 _pure_ static inline bool job_type_is_mergeable(JobType a, JobType b) {
 186         return job_type_lookup_merge(a, b) >= 0;
 187 }
 188
 189 _pure_ static inline bool job_type_is_conflicting(JobType a, JobType b) {
 190         return a != JOB_NOP && b != JOB_NOP && !job_type_is_mergeable(a, b);
 191 }
 192
 193 _pure_ static inline bool job_type_is_superset(JobType a, JobType b) {
 194         /* Checks whether operation a is a "superset" of b in its actions */
 195         if (b == JOB_NOP)
 196                 return true;
 197         if (a == JOB_NOP)
 198                 return false;
 199         return a == job_type_lookup_merge(a, b);
 200 }
 201
 202 bool job_type_is_redundant(JobType a, UnitActiveState b) _pure_;
 203
 204 /* Collapses a state-dependent job type into a simpler type by observing
 205  * the state of the unit which it is going to be applied to. */
 206 JobType job_type_collapse(JobType t, Unit *u);
 207
 208 int job_type_merge_and_collapse(JobType *a, JobType b, Unit *u);
 209
 210 void job_add_to_run_queue(Job *j);
 211 void job_add_to_dbus_queue(Job *j);
 212
 213 int job_start_timer(Job *j, bool job_running);
 214
 215 int job_run_and_invalidate(Job *j);
 216 int job_finish_and_invalidate(Job *j, JobResult result, bool recursive, bool already);
 217
 218 char *job_dbus_path(Job *j);
 219
 220 void job_shutdown_magic(Job *j);
 221
 222 int job_get_timeout(Job *j, usec_t *timeout) _pure_;
 223
 224 bool job_may_gc(Job *j);
 225 void job_add_to_gc_queue(Job *j);
 226
 227 int job_get_before(Job *j, Job*** ret);
 228 int job_get_after(Job *j, Job*** ret);
 229
 230 const char* job_type_to_string(JobType t) _const_;
 231 JobType job_type_from_string(const char *s) _pure_;
 232
 233 const char* job_state_to_string(JobState t) _const_;
 234 JobState job_state_from_string(const char *s) _pure_;
 235
 236 const char* job_mode_to_string(JobMode t) _const_;
 237 JobMode job_mode_from_string(const char *s) _pure_;
 238
 239 const char* job_result_to_string(JobResult t) _const_;
 240 JobResult job_result_from_string(const char *s) _pure_;
 241
 242 const char* job_type_to_access_method(JobType t);