job.c

   1 /*
   2  * Background jobs (long-running operations)
   3  *
   4  * Copyright (c) 2011 IBM Corp.
   5  * Copyright (c) 2012, 2018 Red Hat, Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include "qemu-common.h"
  28 #include "qapi/error.h"
  29 #include "qemu/job.h"
  30 #include "qemu/id.h"
  31 #include "trace-root.h"
  32
  33 static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
  34
  35 /* Job State Transition Table */
  36 bool JobSTT[JOB_STATUS__MAX][JOB_STATUS__MAX] = {
  37                                     /* U, C, R, P, Y, S, W, D, X, E, N */
  38     /* U: */ [JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
  39     /* C: */ [JOB_STATUS_CREATED]   = {0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1},
  40     /* R: */ [JOB_STATUS_RUNNING]   = {0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0},
  41     /* P: */ [JOB_STATUS_PAUSED]    = {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
  42     /* Y: */ [JOB_STATUS_READY]     = {0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0},
  43     /* S: */ [JOB_STATUS_STANDBY]   = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
  44     /* W: */ [JOB_STATUS_WAITING]   = {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0},
  45     /* D: */ [JOB_STATUS_PENDING]   = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
  46     /* X: */ [JOB_STATUS_ABORTING]  = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
  47     /* E: */ [JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
  48     /* N: */ [JOB_STATUS_NULL]      = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
  49 };
  50
  51 bool JobVerbTable[JOB_VERB__MAX][JOB_STATUS__MAX] = {
  52                                     /* U, C, R, P, Y, S, W, D, X, E, N */
  53     [JOB_VERB_CANCEL]               = {0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0},
  54     [JOB_VERB_PAUSE]                = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
  55     [JOB_VERB_RESUME]               = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
  56     [JOB_VERB_SET_SPEED]            = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
  57     [JOB_VERB_COMPLETE]             = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
  58     [JOB_VERB_FINALIZE]             = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
  59     [JOB_VERB_DISMISS]              = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
  60 };
  61
  62 /* TODO Make static once the whole state machine is in job.c */
  63 void job_state_transition(Job *job, JobStatus s1)
  64 {
  65     JobStatus s0 = job->status;
  66     assert(s1 >= 0 && s1 <= JOB_STATUS__MAX);
  67     trace_job_state_transition(job, /* TODO re-enable: job->ret */ 0,
  68                                JobSTT[s0][s1] ? "allowed" : "disallowed",
  69                                JobStatus_str(s0), JobStatus_str(s1));
  70     assert(JobSTT[s0][s1]);
  71     job->status = s1;
  72 }
  73
  74 int job_apply_verb(Job *job, JobVerb verb, Error **errp)
  75 {
  76     JobStatus s0 = job->status;
  77     assert(verb >= 0 && verb <= JOB_VERB__MAX);
  78     trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
  79                          JobVerbTable[verb][s0] ? "allowed" : "prohibited");
  80     if (JobVerbTable[verb][s0]) {
  81         return 0;
  82     }
  83     error_setg(errp, "Job '%s' in state '%s' cannot accept command verb '%s'",
  84                job->id, JobStatus_str(s0), JobVerb_str(verb));
  85     return -EPERM;
  86 }
  87
  88 JobType job_type(const Job *job)
  89 {
  90     return job->driver->job_type;
  91 }
  92
  93 const char *job_type_str(const Job *job)
  94 {
  95     return JobType_str(job_type(job));
  96 }
  97
  98 Job *job_next(Job *job)
  99 {
 100     if (!job) {
 101         return QLIST_FIRST(&jobs);
 102     }
 103     return QLIST_NEXT(job, job_list);
 104 }
 105
 106 Job *job_get(const char *id)
 107 {
 108     Job *job;
 109
 110     QLIST_FOREACH(job, &jobs, job_list) {
 111         if (job->id && !strcmp(id, job->id)) {
 112             return job;
 113         }
 114     }
 115
 116     return NULL;
 117 }
 118
 119 void *job_create(const char *job_id, const JobDriver *driver, Error **errp)
 120 {
 121     Job *job;
 122
 123     if (job_id) {
 124         if (!id_wellformed(job_id)) {
 125             error_setg(errp, "Invalid job ID '%s'", job_id);
 126             return NULL;
 127         }
 128         if (job_get(job_id)) {
 129             error_setg(errp, "Job ID '%s' already in use", job_id);
 130             return NULL;
 131         }
 132     }
 133
 134     job = g_malloc0(driver->instance_size);
 135     job->driver        = driver;
 136     job->id            = g_strdup(job_id);
 137     job->refcnt        = 1;
 138
 139     job_state_transition(job, JOB_STATUS_CREATED);
 140
 141     QLIST_INSERT_HEAD(&jobs, job, job_list);
 142
 143     return job;
 144 }
 145
 146 void job_ref(Job *job)
 147 {
 148     ++job->refcnt;
 149 }
 150
 151 void job_unref(Job *job)
 152 {
 153     if (--job->refcnt == 0) {
 154         assert(job->status == JOB_STATUS_NULL);
 155
 156         if (job->driver->free) {
 157             job->driver->free(job);
 158         }
 159
 160         QLIST_REMOVE(job, job_list);
 161
 162         g_free(job->id);
 163         g_free(job);
 164     }
 165 }