X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=manager.c;h=7941d89a75f52c86dbf8ce729255e3cf1c36a400;hp=41124fff8972999aef1b4c580afd238037cac51a;hb=83c60c9f0c7581b607dc5c0f84582978894e3d4a;hpb=1e198baf11cd0c34ef0c6f326c8a75b046552a33 diff --git a/manager.c b/manager.c index 41124fff8..7941d89a7 100644 --- a/manager.c +++ b/manager.c @@ -51,6 +51,28 @@ void manager_free(Manager *m) { free(m); } +static void transaction_delete_job(Manager *m, Job *j) { + assert(m); + assert(j); + + /* Deletes one job from the transaction */ + + manager_transaction_unlink_job(m, j); + + if (!j->linked) + job_free(j); +} + +static void transaction_delete_name(Manager *m, Name *n) { + Job *j; + + /* Deletes all jobs associated with a certain name from the + * transaction */ + + while ((j = hashmap_get(m->transaction_jobs, n))) + transaction_delete_job(m, j); +} + static void transaction_abort(Manager *m) { Job *j; @@ -58,7 +80,7 @@ static void transaction_abort(Manager *m) { while ((j = hashmap_first(m->transaction_jobs))) if (j->linked) - manager_transaction_delete_job(m, j); + transaction_delete_job(m, j); else job_free(j); @@ -71,6 +93,11 @@ static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsi assert(m); + /* A recursive sweep through the graph that marks all names + * that matter to the anchor job, i.e. are directly or + * indirectly a dependency of the anchor job via paths that + * are fully marked as mattering. */ + for (l = j ? j->subject_list : m->transaction_anchor; l; l = l->subject_next) { /* This link does not matter */ @@ -88,40 +115,6 @@ static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsi } } -static bool types_match(JobType a, JobType b, JobType c, JobType d) { - return - (a == c && b == d) || - (a == d && b == c); -} - -static int types_merge(JobType *a, JobType b) { - if (*a == b) - return 0; - - if (types_match(*a, b, JOB_START, JOB_VERIFY_STARTED)) - *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_STARTED, 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_STARTED, 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_STARTED, JOB_RELOAD)) - *a = JOB_RELOAD; - else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_TRY_RESTART) || - types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART)) - *a = JOB_TRY_RESTART; - - return -EEXIST; -} - static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) { JobDependency *l, *last; @@ -130,8 +123,11 @@ static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, Job assert(j->name == other->name); assert(!j->linked); + /* Merges 'other' into 'j' and then deletes j. */ + j->type = t; j->state = JOB_WAITING; + j->forced = j->forced || other->forced; j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor; @@ -170,7 +166,45 @@ static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, Job /* Kill the other job */ other->subject_list = NULL; other->object_list = NULL; - manager_transaction_delete_job(m, other); + transaction_delete_job(m, other); +} + +static int delete_one_unmergeable_job(Manager *m, Job *j) { + Job *k; + + assert(j); + + /* Tries to delete one item in the linked list + * j->transaction_next->transaction_next->... that conflicts + * whith another one, in an attempt to make an inconsistent + * transaction work. */ + + /* We rely here on the fact that if a merged with b does not + * merge with c, either a or b merge with c neither */ + for (; j; j = j->transaction_next) + for (k = j->transaction_next; k; k = k->transaction_next) { + Job *d; + + /* Is this one mergeable? Then skip it */ + if (job_type_is_mergeable(j->type, k->type)) + continue; + + /* Ok, we found two that conflict, let's see if we can + * drop one of them */ + if (!j->matters_to_anchor) + d = j; + else if (!k->matters_to_anchor) + d = k; + else + return -ENOEXEC; + + /* Ok, we can drop one, so let's do so. */ + log_debug("Try to fix job merging by deleting job %s/%s", name_id(d->name), job_type_to_string(d->type)); + transaction_delete_job(m, d); + return 0; + } + + return -EINVAL; } static int transaction_merge_jobs(Manager *m) { @@ -180,13 +214,44 @@ static int transaction_merge_jobs(Manager *m) { assert(m); + /* First step, check whether any of the jobs for one specific + * task conflict. If so, try to drop one of them. */ + HASHMAP_FOREACH(j, m->transaction_jobs, state) { + JobType t; + Job *k; + + t = j->type; + for (k = j->transaction_next; k; k = k->transaction_next) { + if ((r = job_type_merge(&t, k->type)) >= 0) + continue; + + /* OK, we could not merge all jobs for this + * action. Let's see if we can get rid of one + * of them */ + + if ((r = delete_one_unmergeable_job(m, j)) >= 0) + /* Ok, we managed to drop one, now + * let's ask our callers to call us + * again after garbage collecting */ + return -EAGAIN; + + /* We couldn't merge anything. Failure */ + return r; + } + } + + /* Second step, merge the jobs. */ HASHMAP_FOREACH(j, m->transaction_jobs, state) { JobType t = j->type; Job *k; + /* Merge all transactions */ for (k = j->transaction_next; k; k = k->transaction_next) - if ((r = types_merge(&t, k->type)) < 0) - return r; + assert_se(job_type_merge(&t, k->type) == 0); + + /* If an active job is mergeable, merge it too */ + if (j->name->meta.job) + job_type_merge(&t, j->name->meta.job->type); /* Might fail. Which is OK */ while ((k = j->transaction_next)) { if (j->linked) { @@ -203,6 +268,20 @@ static int transaction_merge_jobs(Manager *m) { return 0; } +static bool name_matters_to_anchor(Name *n, Job *j) { + assert(n); + assert(!j->transaction_prev); + + /* Checks whether at least one of the jobs for this name + * matters to the anchor. */ + + for (; j; j = j->transaction_next) + if (j->matters_to_anchor) + return true; + + return false; +} + static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) { void *state; Name *n; @@ -210,19 +289,30 @@ static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned assert(m); assert(j); + assert(!j->transaction_prev); + + /* Does a recursive sweep through the ordering graph, looking + * for a cycle. If we find cycle we try to break it. */ /* Did we find a cycle? */ if (j->marker && j->generation == generation) { Job *k; /* So, we already have been here. We have a - * cycle. Let's try to break it. We go backwards in our - * path and try to find a suitable job to remove. */ + * cycle. Let's try to break it. We go backwards in + * our path and try to find a suitable job to + * remove. We use the marker to find our way back, + * since smart how we are we stored our way back in + * there. */ for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) { - if (!k->matters_to_anchor) { - log_debug("Breaking order cycle by deleting job %s", name_id(k->name)); - manager_transaction_delete_job(m, k); + + if (!k->linked && + !name_matters_to_anchor(k->name, k)) { + /* Ok, we can drop this one, so let's + * do so. */ + log_debug("Breaking order cycle by deleting job %s/%s", name_id(k->name), job_type_to_string(k->type)); + transaction_delete_name(m, k->name); return -EAGAIN; } @@ -232,19 +322,25 @@ static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned break; } - return -ELOOP; + return -ENOEXEC; } + /* Make the marker point to where we come from, so that we can + * find our way backwards if we want to break a cycle */ j->marker = from; j->generation = generation; - /* We assume that the the dependencies are both-ways, and + /* We assume that the the dependencies are bidirectional, and * hence can ignore NAME_AFTER */ - SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], state) { Job *o; + /* Is there a job for this name? */ if (!(o = hashmap_get(m->transaction_jobs, n))) + + /* Ok, there is no job for this in the + * transaction, but maybe there is already one + * running? */ if (!(o = n->meta.job)) continue; @@ -256,36 +352,19 @@ static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned } static int transaction_verify_order(Manager *m, unsigned *generation) { - bool again; + Job *j; + int r; + void *state; + assert(m); assert(generation); - do { - Job *j; - int r; - void *state; - - again = false; - - HASHMAP_FOREACH(j, m->transaction_jobs, state) { - - /* Assume merged */ - assert(!j->transaction_next); - assert(!j->transaction_prev); + /* Check if the ordering graph is cyclic. If it is, try to fix + * that up by dropping one of the jobs. */ - if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0) { - - /* There was a cycleq, but it was fixed, - * we need to restart our algorithm */ - if (r == -EAGAIN) { - again = true; - break; - } - - return r; - } - } - } while (again); + HASHMAP_FOREACH(j, m->transaction_jobs, state) + if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0) + return r; return 0; } @@ -295,6 +374,8 @@ static void transaction_collect_garbage(Manager *m) { assert(m); + /* Drop jobs that are not required by any other job */ + do { void *state; Job *j; @@ -305,7 +386,8 @@ static void transaction_collect_garbage(Manager *m) { if (j->object_list) continue; - manager_transaction_delete_job(m, j); + log_debug("Garbage collecting job %s/%s", name_id(j->name), job_type_to_string(j->type)); + transaction_delete_job(m, j); again = true; break; } @@ -322,19 +404,74 @@ static int transaction_is_destructive(Manager *m, JobMode mode) { /* Checks whether applying this transaction means that * existing jobs would be replaced */ - HASHMAP_FOREACH(j, m->transaction_jobs, state) - if (j->name->meta.job && j->name->meta.job != j) + HASHMAP_FOREACH(j, m->transaction_jobs, state) { + + /* Assume merged */ + assert(!j->transaction_prev); + assert(!j->transaction_next); + + if (j->name->meta.job && + j->name->meta.job != j && + !job_type_is_superset(j->type, j->name->meta.job->type)) return -EEXIST; + } return 0; } +static void transaction_minimize_impact(Manager *m) { + bool again; + assert(m); + + /* Drops all unnecessary jobs that reverse already active jobs + * or that stop a running service. */ + + do { + Job *j; + void *state; + + again = false; + + HASHMAP_FOREACH(j, m->transaction_jobs, state) { + for (; j; j = j->transaction_next) { + + /* If it matters, we shouldn't drop it */ + if (j->matters_to_anchor) + continue; + + /* Would this stop a running service? + * Would this change an existing job? + * If so, let's drop this entry */ + if ((j->type != JOB_STOP || NAME_IS_INACTIVE_OR_DEACTIVATING(name_active_state(j->name))) && + (!j->name->meta.job || job_type_is_conflicting(j->type, j->name->meta.job->state))) + continue; + + /* Ok, let's get rid of this */ + log_debug("Deleting %s/%s to minimize impact", name_id(j->name), job_type_to_string(j->type)); + transaction_delete_job(m, j); + again = true; + break; + } + + if (again) + break; + } + + } while (again); +} + static int transaction_apply(Manager *m, JobMode mode) { void *state; Job *j; int r; + /* Moves the transaction jobs to the set of active jobs */ + HASHMAP_FOREACH(j, m->transaction_jobs, state) { + /* Assume merged */ + assert(!j->transaction_prev); + assert(!j->transaction_next); + if (j->linked) continue; @@ -364,6 +501,8 @@ static int transaction_apply(Manager *m, JobMode mode) { job_dependency_free(j->object_list); } + m->transaction_anchor = NULL; + return 0; rollback: @@ -378,7 +517,6 @@ rollback: return r; } - static int transaction_activate(Manager *m, JobMode mode) { int r; unsigned generation = 1; @@ -391,23 +529,52 @@ static int transaction_activate(Manager *m, JobMode mode) { /* First step: figure out which jobs matter */ transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++); - /* Second step: let's merge entries we can merge */ - if ((r = transaction_merge_jobs(m)) < 0) - goto rollback; + /* Second step: Try not to stop any running services if + * we don't have to. Don't try to reverse running + * jobs if we don't have to. */ + transaction_minimize_impact(m); - /* Third step: verify order makes sense */ - if ((r = transaction_verify_order(m, &generation)) < 0) - goto rollback; + for (;;) { + /* Third step: Let's remove unneeded jobs that might + * be lurking. */ + transaction_collect_garbage(m); - /* Third step: do garbage colletion */ - transaction_collect_garbage(m); + /* Fourth step: verify order makes sense and correct + * cycles if necessary and possible */ + if ((r = transaction_verify_order(m, &generation)) >= 0) + break; + + if (r != -EAGAIN) + goto rollback; + + /* Let's see if the resulting transaction ordering + * graph is still cyclic... */ + } + + for (;;) { + /* Fifth step: let's drop unmergeable entries if + * necessary and possible, merge entries we can + * merge */ + if ((r = transaction_merge_jobs(m)) >= 0) + break; - /* Fourth step: check whether we can actually apply this */ + if (r != -EAGAIN) + goto rollback; + + /* Sixth step: an entry got dropped, let's garbage + * collect its dependencies. */ + transaction_collect_garbage(m); + + /* Let's see if the resulting transaction still has + * unmergeable entries ... */ + } + + /* Seventh step: check whether we can actually apply this */ if (mode == JOB_FAIL) if ((r = transaction_is_destructive(m, mode)) < 0) goto rollback; - /* Fifth step: apply changes */ + /* Eights step: apply changes */ if ((r = transaction_apply(m, mode)) < 0) goto rollback; @@ -421,7 +588,7 @@ rollback: return r; } -static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool *is_new) { +static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool force, bool *is_new) { Job *j, *f; int r; @@ -462,6 +629,7 @@ static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool * j->generation = 0; j->marker = NULL; j->matters_to_anchor = false; + j->forced = force; if (is_new) *is_new = true; @@ -469,7 +637,7 @@ static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool * return j; } -void manager_transaction_delete_job(Manager *m, Job *j) { +void manager_transaction_unlink_job(Manager *m, Job *j) { assert(m); assert(j); @@ -494,8 +662,10 @@ void manager_transaction_delete_job(Manager *m, Job *j) { job_dependency_free(j->object_list); if (other) { - log_debug("Deleting job %s, as dependency of job %s", name_id(j->name), name_id(other->name)); - manager_transaction_delete_job(m, other); + log_debug("Deleting job %s/%s as dependency of job %s/%s", + name_id(other->name), job_type_to_string(other->type), + name_id(j->name), job_type_to_string(j->type)); + transaction_delete_job(m, other); } } } @@ -511,8 +681,14 @@ static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name * assert(type < _JOB_TYPE_MAX); assert(name); + if (name->meta.load_state != NAME_LOADED) + return -EINVAL; + + if (!job_type_is_applicable(type, name->meta.type)) + return -EBADR; + /* First add the job. */ - if (!(ret = transaction_add_one_job(m, type, name, &is_new))) + if (!(ret = transaction_add_one_job(m, type, name, force, &is_new))) return -ENOMEM; /* Then, add a link to the job. */ @@ -523,28 +699,28 @@ static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name * /* Finally, recursively add in all dependencies. */ if (type == JOB_START || type == JOB_RELOAD_OR_START) { SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR) goto fail; SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR) goto fail; SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR) goto fail; SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, true, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR) goto fail; SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, !force, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR) goto fail; SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], state) - if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR) goto fail; } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) { SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], state) - if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0) + if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR) goto fail; } @@ -649,10 +825,10 @@ int manager_load_name(Manager *m, const char *name, Name **_ret) { return -ENOMEM; } - if (set_put(ret->meta.names, n) < 0) { + if ((r = set_put(ret->meta.names, n)) < 0) { name_free(ret); free(n); - return -ENOMEM; + return r; } if ((r = name_link(ret)) < 0) { @@ -706,3 +882,13 @@ void manager_clear_jobs(Manager *m) { while ((j = hashmap_first(m->jobs))) job_free(j); } + +void manager_run_jobs(Manager *m) { + Job *j; + void *state; + int r; + + HASHMAP_FOREACH(j, m->jobs, state) { + r = job_run_and_invalidate(j); + } +}