src/core/job.h

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