X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=job.c;h=81d7a19734698516cb20b40dcfc395e50d59ecfe;hp=87bcd289d98eafc8185fcbc2f194172eb431acf2;hb=034c6ed7da5e44bfdde5a5d0da75f7b7a59953b8;hpb=a66d02c3290008d50b2b52f84cfbf46a546ba831

diff --git a/job.c b/job.c
index 87bcd289d..81d7a1973 100644
--- a/job.c
+++ b/job.c
@@ -1,6 +1,7 @@
 /*-*- Mode: C; c-basic-offset: 8 -*-*/
 
 #include <assert.h>
+#include <errno.h>
 
 #include "macro.h"
 #include "job.h"
@@ -20,71 +21,471 @@ Job* job_new(Manager *m, JobType type, Name *name) {
         j->type = type;
         j->name = name;
 
-        /* We don't link it here, that's what job_link() is for */
+        /* We don't link it here, that's what job_dependency() is for */
 
         return j;
 }
 
-int job_link(Job *j) {
-        int r;
-
+void job_free(Job *j) {
         assert(j);
-        assert(!j->linked);
 
-        if ((r = hashmap_put(j->manager->jobs, UINT32_TO_PTR(j->id), j)) < 0)
-                return r;
+        /* Detach from next 'bigger' objects */
+        if (j->linked) {
+                if (j->name->meta.job == j)
+                        j->name->meta.job = NULL;
 
-        j->name->meta.job = j;
+                hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
+                j->linked = false;
+        }
 
-        j->linked = true;
+        /* Detach from next 'smaller' objects */
+        manager_transaction_unlink_job(j->manager, j);
 
-        return 0;
+        free(j);
 }
 
-void job_free(Job *j) {
-        assert(j);
+JobDependency* job_dependency_new(Job *subject, Job *object, bool matters) {
+        JobDependency *l;
 
-        /* Detach from next 'bigger' objects */
+        assert(object);
 
-        if (j->linked) {
-                assert(j->name);
-                assert(j->name->meta.job == j);
-                j->name->meta.job = NULL;
+        /* Adds a new job link, which encodes that the 'subject' job
+         * needs the 'object' job in some way. If 'subject' is NULL
+         * this means the 'anchor' job (i.e. the one the user
+         * explcitily asked for) is the requester. */
 
-                hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
+        if (!(l = new0(JobDependency, 1)))
+                return NULL;
+
+        l->subject = subject;
+        l->object = object;
+        l->matters = matters;
+
+        if (subject) {
+                l->subject_next = subject->subject_list;
+                subject->subject_list = l;
+        } else {
+                l->subject_next = object->manager->transaction_anchor;
+                object->manager->transaction_anchor = l;
         }
 
-        hashmap_remove(j->manager->jobs_to_add, j->name);
-        set_remove(j->manager->jobs_to_remove, j);
+        if (l->subject_next)
+                l->subject_next->subject_prev = l;
+        l->subject_prev = NULL;
 
-        /* Free data and next 'smaller' objects */
-        free(j);
+        if ((l->object_next = object->object_list))
+                l->object_next->object_prev = l;
+        l->object_prev = NULL;
+        object->object_list = l;
+
+        return l;
+}
+
+void job_dependency_free(JobDependency *l) {
+        assert(l);
+
+        if (l->subject_prev)
+                l->subject_prev->subject_next = l->subject_next;
+        else if (l->subject)
+                l->subject->subject_list = l->subject_next;
+        else
+                l->object->manager->transaction_anchor = l->subject_next;
+
+        if (l->subject_next)
+                l->subject_next->subject_prev = l->subject_prev;
+
+        if (l->object_prev)
+                l->object_prev->object_next = l->object_next;
+        else
+                l->object->object_list = l->object_next;
+
+        if (l->object_next)
+                l->object_next->object_prev = l->object_prev;
+
+        free(l);
+}
+
+void job_dependency_delete(Job *subject, Job *object, bool *matters) {
+        JobDependency *l;
+
+        assert(object);
+
+        for (l = object->object_list; l; l = l->object_next) {
+                assert(l->object == object);
+
+                if (l->subject == subject)
+                        break;
+        }
+
+        if (!l) {
+                if (matters)
+                        *matters = false;
+                return;
+        }
+
+        if (matters)
+                *matters = l->matters;
+
+        job_dependency_free(l);
 }
 
-void job_dump(Job *j, FILE*f) {
+const char* job_type_to_string(JobType t) {
 
         static const char* const job_type_table[_JOB_TYPE_MAX] = {
-                [JOB_START] = "START",
-                [JOB_STOP] = "STOP",
-                [JOB_VERIFY_STARTED] = "VERIFY_STARTED",
-                [JOB_RELOAD] = "RELOAD",
-                [JOB_RESTART] = "RESTART",
-                [JOB_TRY_RESTART] = "TRY_RESTART",
-                [JOB_RESTART_FINISH] = "RESTART_FINISH"
+                [JOB_START] = "start",
+                [JOB_VERIFY_ACTIVE] = "verify-active",
+                [JOB_STOP] = "stop",
+                [JOB_RELOAD] = "reload",
+                [JOB_RELOAD_OR_START] = "reload-or-start",
+                [JOB_RESTART] = "restart",
+                [JOB_TRY_RESTART] = "try-restart",
         };
 
+        if (t < 0 || t >= _JOB_TYPE_MAX)
+                return "n/a";
+
+        return job_type_table[t];
+}
+
+void job_dump(Job *j, FILE*f, const char *prefix) {
+
         static const char* const job_state_table[_JOB_STATE_MAX] = {
-                [JOB_WAITING] = "WAITING",
-                [JOB_RUNNING] = "RUNNING",
-                [JOB_DONE] = "DONE"
+                [JOB_WAITING] = "waiting",
+                [JOB_RUNNING] = "running"
         };
 
         assert(j);
         assert(f);
 
-        fprintf(f, "Job %u: %s → %s in state %s\n",
-                j->id,
-                name_id(j->name),
-                job_type_table[j->type],
-                job_state_table[j->state]);
+        fprintf(f,
+                "%sJob %u:\n"
+                "%s\tAction: %s → %s\n"
+                "%s\tState: %s\n"
+                "%s\tForced: %s\n",
+                prefix, j->id,
+                prefix, name_id(j->name), job_type_to_string(j->type),
+                prefix, job_state_table[j->state],
+                prefix, yes_no(j->forced));
+}
+
+bool job_is_anchor(Job *j) {
+        JobDependency *l;
+
+        assert(j);
+
+        for (l = j->object_list; l; l = l->object_next)
+                if (!l->subject)
+                        return true;
+
+        return false;
+}
+
+static bool types_match(JobType a, JobType b, JobType c, JobType d) {
+        return
+                (a == c && b == d) ||
+                (a == d && b == c);
+}
+
+int job_type_merge(JobType *a, JobType b) {
+        if (*a == b)
+                return 0;
+
+        /* Merging is associative! a merged with b merged with c is
+         * the same as a merged with c merged with b. */
+
+        /* Mergeability is transitive! if a can be merged with b and b
+         * with c then a also with c */
+
+        /* Also, if a merged with b cannot be merged with c, then
+         * either a or b cannot be merged with c either */
+
+        if (types_match(*a, b, JOB_START, JOB_VERIFY_ACTIVE))
+                *a = JOB_START;
+        else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
+                 types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
+                 types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD_OR_START) ||
+                 types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
+                *a = JOB_RELOAD_OR_START;
+        else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
+                 types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
+                 types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RESTART) ||
+                 types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
+                 types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
+                 types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
+                 types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
+                *a = JOB_RESTART;
+        else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD))
+                *a = JOB_RELOAD;
+        else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_TRY_RESTART) ||
+                 types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
+                *a = JOB_TRY_RESTART;
+        else
+                return -EEXIST;
+
+        return 0;
+}
+
+bool job_type_is_mergeable(JobType a, JobType b) {
+        return job_type_merge(&a, b) >= 0;
+}
+
+bool job_type_is_superset(JobType a, JobType b) {
+
+        /* Checks whether operation a is a "superset" of b in its
+         * actions */
+
+        if (a == b)
+                return true;
+
+        switch (a) {
+                case JOB_START:
+                        return b == JOB_VERIFY_ACTIVE;
+
+                case JOB_RELOAD:
+                        return
+                                b == JOB_VERIFY_ACTIVE;
+
+                case JOB_RELOAD_OR_START:
+                        return
+                                b == JOB_RELOAD ||
+                                b == JOB_START ||
+                                b == JOB_VERIFY_ACTIVE;
+
+                case JOB_RESTART:
+                        return
+                                b == JOB_START ||
+                                b == JOB_VERIFY_ACTIVE ||
+                                b == JOB_RELOAD ||
+                                b == JOB_RELOAD_OR_START ||
+                                b == JOB_TRY_RESTART;
+
+                case JOB_TRY_RESTART:
+                        return
+                                b == JOB_VERIFY_ACTIVE ||
+                                b == JOB_RELOAD;
+                default:
+                        return false;
+
+        }
+}
+
+bool job_type_is_conflicting(JobType a, JobType b) {
+        assert(a >= 0 && a < _JOB_TYPE_MAX);
+        assert(b >= 0 && b < _JOB_TYPE_MAX);
+
+        return (a == JOB_STOP) != (b == JOB_STOP);
+}
+
+bool job_is_runnable(Job *j) {
+        Iterator i;
+        Name *other;
+
+        assert(j);
+        assert(j->linked);
+
+        /* Checks whether there is any job running for the names this
+         * job needs to be running after (in the case of a 'positive'
+         * job type) or before (in the case of a 'negative' job type
+         * . */
+
+        if (j->type == JOB_START ||
+            j->type == JOB_VERIFY_ACTIVE ||
+            j->type == JOB_RELOAD ||
+            j->type == JOB_RELOAD_OR_START) {
+
+                /* Immediate result is that the job is or might be
+                 * started. In this case lets wait for the
+                 * dependencies, regardless whether they are
+                 * starting or stopping something. */
+
+                SET_FOREACH(other, j->name->meta.dependencies[NAME_AFTER], i)
+                        if (other->meta.job)
+                                return false;
+        }
+
+        /* Also, if something else is being stopped and we should
+         * change state after it, then lets wait. */
+
+        SET_FOREACH(other, j->name->meta.dependencies[NAME_BEFORE], i)
+                if (other->meta.job &&
+                    (other->meta.job->type == JOB_STOP ||
+                     other->meta.job->type == JOB_RESTART ||
+                     other->meta.job->type == JOB_TRY_RESTART))
+                        return false;
+
+        /* This means that for a service a and a service b where b
+         * shall be started after a:
+         *
+         *  start a + start b → 1st step start a, 2nd step start b
+         *  start a + stop b  → 1st step stop b,  2nd step start a
+         *  stop a  + start b → 1st step stop a,  2nd step start b
+         *  stop a  + stop b  → 1st step stop b,  2nd step stop a
+         *
+         *  This has the side effect that restarts are properly
+         *  synchronized too. */
+
+        return true;
+}
+
+int job_run_and_invalidate(Job *j) {
+        int r;
+        assert(j);
+
+        if (j->in_run_queue) {
+                LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
+                j->in_run_queue = false;
+        }
+
+        if (j->state != JOB_WAITING)
+                return 0;
+
+        if (!job_is_runnable(j))
+                return -EAGAIN;
+
+        j->state = JOB_RUNNING;
+
+        switch (j->type) {
+
+                case JOB_START:
+                        r = name_start(j->name);
+                        if (r == -EBADR)
+                                r = 0;
+                        break;
+
+                case JOB_VERIFY_ACTIVE: {
+                        NameActiveState t = name_active_state(j->name);
+                        if (NAME_IS_ACTIVE_OR_RELOADING(t))
+                                r = -EALREADY;
+                        else if (t == NAME_ACTIVATING)
+                                r = -EAGAIN;
+                        else
+                                r = -ENOEXEC;
+                        break;
+                }
+
+                case JOB_STOP:
+                        r = name_stop(j->name);
+                        break;
+
+                case JOB_RELOAD:
+                        r = name_reload(j->name);
+                        break;
+
+                case JOB_RELOAD_OR_START:
+                        if (name_active_state(j->name) == NAME_ACTIVE)
+                                r = name_reload(j->name);
+                        else
+                                r = name_start(j->name);
+                        break;
+
+                case JOB_RESTART: {
+                        NameActiveState t = name_active_state(j->name);
+                        if (t == NAME_INACTIVE || t == NAME_ACTIVATING) {
+                                j->type = JOB_START;
+                                r = name_start(j->name);
+                        } else
+                                r = name_stop(j->name);
+                        break;
+                }
+
+                case JOB_TRY_RESTART: {
+                        NameActiveState t = name_active_state(j->name);
+                        if (t == NAME_INACTIVE || t == NAME_DEACTIVATING)
+                                r = -ENOEXEC;
+                        else if (t == NAME_ACTIVATING) {
+                                j->type = JOB_START;
+                                r = name_start(j->name);
+                        } else
+                                r = name_stop(j->name);
+                        break;
+                }
+
+                default:
+                        ;
+        }
+
+        if (r == -EALREADY)
+                r = job_finish_and_invalidate(j, true);
+        else if (r == -EAGAIN) {
+                j->state = JOB_WAITING;
+                return -EAGAIN;
+        } else if (r < 0)
+                r = job_finish_and_invalidate(j, false);
+
+        return r;
+}
+
+int job_finish_and_invalidate(Job *j, bool success) {
+        Name *n;
+        Name *other;
+        NameType t;
+        Iterator i;
+
+        assert(j);
+
+        /* Patch restart jobs so that they become normal start jobs */
+        if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
+                j->state = JOB_RUNNING;
+                j->type = JOB_START;
+                job_schedule_run(j);
+                return 0;
+        }
+
+        n = j->name;
+        t = j->type;
+        job_free(j);
+
+        /* Fail depending jobs on failure */
+        if (!success) {
+
+                if (t == JOB_START ||
+                    t == JOB_VERIFY_ACTIVE ||
+                    t == JOB_RELOAD_OR_START) {
+
+                        SET_FOREACH(other, n->meta.dependencies[NAME_REQUIRED_BY], i)
+                                if (other->meta.job &&
+                                    (other->meta.type == JOB_START ||
+                                     other->meta.type == JOB_VERIFY_ACTIVE ||
+                                     other->meta.type == JOB_RELOAD_OR_START))
+                                        job_finish_and_invalidate(other->meta.job, false);
+
+                        SET_FOREACH(other, n->meta.dependencies[NAME_SOFT_REQUIRED_BY], i)
+                                if (other->meta.job &&
+                                    !other->meta.job->forced &&
+                                    (other->meta.type == JOB_START ||
+                                     other->meta.type == JOB_VERIFY_ACTIVE ||
+                                     other->meta.type == JOB_RELOAD_OR_START))
+                                        job_finish_and_invalidate(other->meta.job, false);
+
+                } else if (t == JOB_STOP) {
+
+                        SET_FOREACH(other, n->meta.dependencies[NAME_CONFLICTS], i)
+                                if (other->meta.job &&
+                                    (t == JOB_START ||
+                                     t == JOB_VERIFY_ACTIVE ||
+                                     t == JOB_RELOAD_OR_START))
+                                        job_finish_and_invalidate(other->meta.job, false);
+                }
+        }
+
+        /* Try to start the next jobs that can be started */
+        SET_FOREACH(other, n->meta.dependencies[NAME_AFTER], i)
+                if (other->meta.job)
+                        job_schedule_run(other->meta.job);
+        SET_FOREACH(other, n->meta.dependencies[NAME_BEFORE], i)
+                if (other->meta.job)
+                        job_schedule_run(other->meta.job);
+
+        return 0;
+}
+
+void job_schedule_run(Job *j) {
+        assert(j);
+        assert(j->linked);
+
+        if (j->in_run_queue)
+                return;
+
+        LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
+        j->in_run_queue = true;
 }