14630481637

Committed 23 Apr 2025 07:04PM UTC coverage: 72.178% (-0.002%) from 72.18%

Build # 14630481637

Build Type

push

github

Committed by

DaanDeMeyer

Commit Message

mkosi: Run clangd within the tools tree instead of the build container

Running within the build sandbox has a number of disadvantages:
- We have a separate clangd cache for each distribution/release combo
- It requires to build the full image before clangd can be used
- It breaks every time the image becomes out of date and requires a
  rebuild
- We can't look at system headers as we don't have the knowledge to map
  them from inside the build sandbox to the corresponding path on the host

Instead, let's have mkosi.clangd run clangd within the tools tree. We
already require building systemd for both the host and the target anyway,
and all the dependencies to build systemd are installed in the tools tree
already for that, as well as clangd since it's installed together with the
other clang tooling we install in the tools tree. Unlike the previous approach,
this approach only requires the mkosi tools tree to be built upfront, which has
a much higher chance of not invalidating its cache. We can also trivially map
system header lookups from within the sandbox to the path within mkosi.tools
on the host so that starts working as well.

Coverage Stats

297054 of 411557 relevant lines covered (72.18%)

686269.58 hits per line

Source File
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76.75

/src/core/transaction.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <fcntl.h>
#include <unistd.h>

#include "alloc-util.h"
#include "ansi-color.h"
#include "bus-common-errors.h"
#include "bus-error.h"
#include "dbus-unit.h"
#include "manager.h"
#include "slice.h"
#include "strv.h"
#include "terminal-util.h"
#include "transaction.h"

static void transaction_unlink_job(Transaction *tr, Job *j, bool delete_dependencies);

static void transaction_delete_job(Transaction *tr, Job *j, bool delete_dependencies) {
        assert(tr);
        assert(j);

        /* Deletes one job from the transaction */

        transaction_unlink_job(tr, j, delete_dependencies);

        job_free(j);
}

static void transaction_delete_unit(Transaction *tr, Unit *u) {
        Job *j;

        /* Deletes all jobs associated with a certain unit from the
         * transaction */

        while ((j = hashmap_get(tr->jobs, u)))
                transaction_delete_job(tr, j, true);
}

static void transaction_abort(Transaction *tr) {
        Job *j;

        assert(tr);

        while ((j = hashmap_first(tr->jobs)))
                transaction_delete_job(tr, j, false);

        assert(hashmap_isempty(tr->jobs));
}

static void transaction_find_jobs_that_matter_to_anchor(Job *j, unsigned generation) {
        assert(j);

        /* A recursive sweep through the graph that marks all units
         * 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. */

        j->matters_to_anchor = true;
        j->generation = generation;

        LIST_FOREACH(subject, l, j->subject_list) {

                /* This link does not matter */
                if (!l->matters)
                        continue;

                /* This unit has already been marked */
                if (l->object->generation == generation)
                        continue;

                transaction_find_jobs_that_matter_to_anchor(l->object, generation);
        }
}

static void transaction_merge_and_delete_job(Transaction *tr, Job *j, Job *other, JobType t) {
        JobDependency *last;

        assert(j);
        assert(other);
        assert(j->unit == other->unit);
        assert(!j->installed);

        /* Merges 'other' into 'j' and then deletes 'other'. */

        j->type = t;
        j->state = JOB_WAITING;
        j->irreversible = j->irreversible || other->irreversible;
        j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;

        /* Patch us in as new owner of the JobDependency objects */
        last = NULL;
        LIST_FOREACH(subject, l, other->subject_list) {
                assert(l->subject == other);
                l->subject = j;
                last = l;
        }

        /* Merge both lists */
        if (last) {
                last->subject_next = j->subject_list;
                if (j->subject_list)
                        j->subject_list->subject_prev = last;
                j->subject_list = other->subject_list;
        }

        /* Patch us in as new owner of the JobDependency objects */
        last = NULL;
        LIST_FOREACH(object, l, other->object_list) {
                assert(l->object == other);
                l->object = j;
                last = l;
        }

        /* Merge both lists */
        if (last) {
                last->object_next = j->object_list;
                if (j->object_list)
                        j->object_list->object_prev = last;
                j->object_list = other->object_list;
        }

        /* Kill the other job */
        other->subject_list = NULL;
        other->object_list = NULL;
        transaction_delete_job(tr, other, true);
}

static bool job_is_conflicted_by(Job *j) {
        assert(j);

        /* Returns true if this job is pulled in by a least one
         * ConflictedBy dependency. */

        LIST_FOREACH(object, l, j->object_list)
                if (l->conflicts)
                        return true;

        return false;
}

static int delete_one_unmergeable_job(Transaction *tr, Job *job) {
        assert(job);

        /* Tries to delete one item in the linked list
         * j->transaction_next->transaction_next->... that conflicts
         * with 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 */
        LIST_FOREACH(transaction, j, job)
                LIST_FOREACH(transaction, k, j->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 && !k->matters_to_anchor) {

                                /* Both jobs don't matter, so let's
                                 * find the one that is smarter to
                                 * remove. Let's think positive and
                                 * rather remove stops then starts --
                                 * except if something is being
                                 * stopped because it is conflicted by
                                 * another unit in which case we
                                 * rather remove the start. */

                                log_unit_debug(j->unit,
                                               "Looking at job %s/%s conflicted_by=%s",
                                               j->unit->id, job_type_to_string(j->type),
                                               yes_no(j->type == JOB_STOP && job_is_conflicted_by(j)));
                                log_unit_debug(k->unit,
                                               "Looking at job %s/%s conflicted_by=%s",
                                               k->unit->id, job_type_to_string(k->type),
                                               yes_no(k->type == JOB_STOP && job_is_conflicted_by(k)));

                                if (j->type == JOB_STOP) {

                                        if (job_is_conflicted_by(j))
                                                d = k;
                                        else
                                                d = j;

                                } else if (k->type == JOB_STOP) {

                                        if (job_is_conflicted_by(k))
                                                d = j;
                                        else
                                                d = k;
                                } else
                                        d = j;

                        } else 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_unit_debug(d->unit,
                                       "Fixing conflicting jobs %s/%s,%s/%s by deleting job %s/%s",
                                       j->unit->id, job_type_to_string(j->type),
                                       k->unit->id, job_type_to_string(k->type),
                                       d->unit->id, job_type_to_string(d->type));
                        transaction_delete_job(tr, d, true);
                        return 0;
                }

        return -EINVAL;
}

static int transaction_merge_jobs(Transaction *tr, sd_bus_error *e) {
        Job *j;
        int r;

        assert(tr);

        /* First step, check whether any of the jobs for one specific
         * task conflict. If so, try to drop one of them. */
        HASHMAP_FOREACH(j, tr->jobs) {
                JobType t;

                t = j->type;
                LIST_FOREACH(transaction, k, j->transaction_next) {
                        if (job_type_merge_and_collapse(&t, k->type, j->unit) >= 0)
                                continue;

                        /* OK, we could not merge all jobs for this
                         * action. Let's see if we can get rid of one
                         * of them */

                        r = delete_one_unmergeable_job(tr, j);
                        if (r >= 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 sd_bus_error_setf(e, BUS_ERROR_TRANSACTION_JOBS_CONFLICTING,
                                                 "Transaction contains conflicting jobs '%s' and '%s' for %s. "
                                                 "Probably contradicting requirement dependencies configured.",
                                                 job_type_to_string(t),
                                                 job_type_to_string(k->type),
                                                 k->unit->id);
                }
        }

        /* Second step, merge the jobs. */
        HASHMAP_FOREACH(j, tr->jobs) {
                JobType t = j->type;

                /* Merge all transaction jobs for j->unit */
                LIST_FOREACH(transaction, k, j->transaction_next)
                        assert_se(job_type_merge_and_collapse(&t, k->type, j->unit) == 0);

                Job *k;
                while ((k = j->transaction_next)) {
                        if (tr->anchor_job == k) {
                                transaction_merge_and_delete_job(tr, k, j, t);
                                j = k;
                        } else
                                transaction_merge_and_delete_job(tr, j, k, t);
                }

                assert(!j->transaction_next);
                assert(!j->transaction_prev);
        }

        return 0;
}

static void transaction_drop_redundant(Transaction *tr) {
        bool again;

        /* Goes through the transaction and removes all jobs of the units whose jobs are all noops. If not
         * all of a unit's jobs are redundant, they are kept. */

        assert(tr);

        do {
                Job *j;

                again = false;

                HASHMAP_FOREACH(j, tr->jobs) {
                        bool keep = false;

                        LIST_FOREACH(transaction, k, j)
                                if (tr->anchor_job == k ||
                                    !job_type_is_redundant(k->type, unit_active_state(k->unit)) ||
                                    (k->unit->job && job_type_is_conflicting(k->type, k->unit->job->type))) {
                                        keep = true;
                                        break;
                                }

                        if (!keep) {
                                log_trace("Found redundant job %s/%s, dropping from transaction.",
                                          j->unit->id, job_type_to_string(j->type));
                                transaction_delete_job(tr, j, false);
                                again = true;
                                break;
                        }
                }
        } while (again);
}

static bool job_matters_to_anchor(Job *job) {
        assert(job);
        assert(!job->transaction_prev);

        /* Checks whether at least one of the jobs for this transaction matters to the anchor. */

        LIST_FOREACH(transaction, j, job)
                if (j->matters_to_anchor)
                        return true;

        return false;
}

static char* merge_unit_ids(const char* unit_log_field, char * const* pairs) {
        _cleanup_free_ char *ans = NULL;
        size_t size = 0;

        assert(unit_log_field);

        STRV_FOREACH_PAIR(unit_id, job_type, pairs) {
                size_t next;

                if (size > 0)
                        ans[size - 1] = '\n';

                next = strlen(unit_log_field) + strlen(*unit_id);
                if (!GREEDY_REALLOC(ans, size + next + 1))
                        return NULL;

                sprintf(ans + size, "%s%s", unit_log_field, *unit_id);
                size += next + 1;
        }

        if (!ans)
                return strdup("");

        return TAKE_PTR(ans);
}

static int transaction_verify_order_one(Transaction *tr, Job *j, Job *from, unsigned generation, sd_bus_error *e) {

        static const UnitDependencyAtom directions[] = {
                UNIT_ATOM_BEFORE,
                UNIT_ATOM_AFTER,
        };

        int r;

        assert(tr);
        assert(j);
        assert(!j->transaction_prev);

        /* Does a recursive sweep through the ordering graph, looking for a cycle. If we find a cycle we try
         * to break it. */

        /* Have we seen this before? */
        if (j->generation == generation) {
                Job *k, *delete = NULL;
                _cleanup_free_ char **array = NULL, *unit_ids = NULL;

                /* If the marker is NULL we have been here already and decided the job was loop-free from
                 * here. Hence shortcut things and return right-away. */
                if (!j->marker)
                        return 0;

                /* So, the marker is not NULL and 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. 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 != k) ? k->marker : NULL)) {

                        /* For logging below */
                        if (strv_push_pair(&array, k->unit->id, (char*) job_type_to_string(k->type)) < 0)
                                log_oom();

                        if (!delete && hashmap_contains(tr->jobs, k->unit) && !job_matters_to_anchor(k))
                                /* Ok, we can drop this one, so let's do so. */
                                delete = k;

                        /* Check if this in fact was the beginning of the cycle */
                        if (k == j)
                                break;
                }

                unit_ids = merge_unit_ids(unit_log_field(j->unit), array); /* ignore error */

                STRV_FOREACH_PAIR(unit_id, job_type, array)
                        /* logging for j not k here to provide a consistent narrative */
                        log_struct(LOG_WARNING,
                                   LOG_UNIT_MESSAGE(j->unit,
                                                    "Found %s on %s/%s",
                                                    unit_id == array ? "ordering cycle" : "dependency",
                                                    *unit_id, *job_type),
                                   LOG_ITEM("%s", strna(unit_ids)));

                if (delete) {
                        const char *status;
                        /* logging for j not k here to provide a consistent narrative */
                        log_struct(LOG_ERR,
                                   LOG_UNIT_MESSAGE(j->unit,
                                                    "Job %s/%s deleted to break ordering cycle starting with %s/%s",
                                                    delete->unit->id, job_type_to_string(delete->type),
                                                    j->unit->id, job_type_to_string(j->type)),
                                   LOG_ITEM("%s", strna(unit_ids)));

                        if (log_get_show_color())
                                status = ANSI_HIGHLIGHT_RED " SKIP " ANSI_NORMAL;
                        else
                                status = " SKIP ";

                        unit_status_printf(delete->unit,
                                           STATUS_TYPE_NOTICE,
                                           status,
                                           "Ordering cycle found, skipping %s",
                                           unit_status_string(delete->unit, NULL));
                        transaction_delete_unit(tr, delete->unit);
                        return -EAGAIN;
                }

                log_struct(LOG_ERR,
                           LOG_UNIT_MESSAGE(j->unit, "Unable to break cycle starting with %s/%s",
                                            j->unit->id, job_type_to_string(j->type)),
                           LOG_ITEM("%s", strna(unit_ids)));

                return sd_bus_error_setf(e, BUS_ERROR_TRANSACTION_ORDER_IS_CYCLIC,
                                         "Transaction order is cyclic. See system logs for details.");
        }

        /* Make the marker point to where we come from, so that we can
         * find our way backwards if we want to break a cycle. We use
         * a special marker for the beginning: we point to
         * ourselves. */
        j->marker = from ?: j;
        j->generation = generation;

        /* Actual ordering of jobs depends on the unit ordering dependency and job types. We need to traverse
         * the graph over 'before' edges in the actual job execution order. We traverse over both unit
         * ordering dependencies and we test with job_compare() whether it is the 'before' edge in the job
         * execution ordering. */
        FOREACH_ELEMENT(d, directions) {
                Unit *u;

                UNIT_FOREACH_DEPENDENCY(u, j->unit, *d) {
                        Job *o;

                        /* Is there a job for this unit? */
                        o = hashmap_get(tr->jobs, u);
                        if (!o) {
                                /* Ok, there is no job for this in the transaction, but maybe there is
                                 * already one running? */
                                o = u->job;
                                if (!o)
                                        continue;
                        }

                        /* Cut traversing if the job j is not really *before* o. */
                        if (job_compare(j, o, *d) >= 0)
                                continue;

                        r = transaction_verify_order_one(tr, o, j, generation, e);
                        if (r < 0)
                                return r;
                }
        }

        /* Ok, let's backtrack, and remember that this entry is not on
         * our path anymore. */
        j->marker = NULL;

        return 0;
}

static int transaction_verify_order(Transaction *tr, unsigned *generation, sd_bus_error *e) {
        Job *j;
        int r;
        unsigned g;

        assert(tr);
        assert(generation);

        /* Check if the ordering graph is cyclic. If it is, try to fix
         * that up by dropping one of the jobs. */

        g = (*generation)++;

        HASHMAP_FOREACH(j, tr->jobs) {
                r = transaction_verify_order_one(tr, j, NULL, g, e);
                if (r < 0)
                        return r;
        }

        return 0;
}

static void transaction_collect_garbage(Transaction *tr) {
        bool again;

        assert(tr);

        /* Drop jobs that are not required by any other job */

        do {
                Job *j;

                again = false;

                HASHMAP_FOREACH(j, tr->jobs) {
                        if (tr->anchor_job == j)
                                continue;

                        if (!j->object_list) {
                                log_trace("Garbage collecting job %s/%s", j->unit->id, job_type_to_string(j->type));
                                transaction_delete_job(tr, j, true);
                                again = true;
                                break;
                        }

                        log_trace("Keeping job %s/%s because of %s/%s",
                                  j->unit->id, job_type_to_string(j->type),
                                  j->object_list->subject ? j->object_list->subject->unit->id : "root",
                                  j->object_list->subject ? job_type_to_string(j->object_list->subject->type) : "root");
                }

        } while (again);
}

static int transaction_is_destructive(Transaction *tr, JobMode mode, sd_bus_error *e) {
        Job *j;

        assert(tr);

        /* Checks whether applying this transaction means that
         * existing jobs would be replaced */

        HASHMAP_FOREACH(j, tr->jobs) {

                /* Assume merged */
                assert(!j->transaction_prev);
                assert(!j->transaction_next);

                if (j->unit->job && (mode == JOB_FAIL || j->unit->job->irreversible) &&
                    job_type_is_conflicting(j->unit->job->type, j->type))
                        return sd_bus_error_setf(e, BUS_ERROR_TRANSACTION_IS_DESTRUCTIVE,
                                                 "Transaction for %s/%s is destructive (%s has '%s' job queued, but '%s' is included in transaction).",
                                                 tr->anchor_job->unit->id, job_type_to_string(tr->anchor_job->type),
                                                 j->unit->id, job_type_to_string(j->unit->job->type), job_type_to_string(j->type));
        }

        return 0;
}

static void transaction_minimize_impact(Transaction *tr) {
        Job *head;

        assert(tr);

        /* Drops all unnecessary jobs that reverse already active jobs
         * or that stop a running service. */

rescan:
        HASHMAP_FOREACH(head, tr->jobs) {
                LIST_FOREACH(transaction, j, head) {
                        bool stops_running_service, changes_existing_job;

                        /* 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 */

                        stops_running_service =
                                j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));

                        changes_existing_job =
                                j->unit->job &&
                                job_type_is_conflicting(j->type, j->unit->job->type);

                        if (!stops_running_service && !changes_existing_job)
                                continue;

                        if (stops_running_service)
                                log_unit_debug(j->unit,
                                               "%s/%s would stop a running service.",
                                               j->unit->id, job_type_to_string(j->type));

                        if (changes_existing_job)
                                log_unit_debug(j->unit,
                                               "%s/%s would change existing job.",
                                               j->unit->id, job_type_to_string(j->type));

                        /* Ok, let's get rid of this */
                        log_unit_debug(j->unit,
                                       "Deleting %s/%s to minimize impact.",
                                       j->unit->id, job_type_to_string(j->type));

                        transaction_delete_job(tr, j, true);
                        goto rescan;
                }
        }
}

static int transaction_apply(
                Transaction *tr,
                Manager *m,
                JobMode mode,
                Set *affected_jobs) {

        Job *j;
        int r;

        assert(tr);
        assert(m);

        /* Moves the transaction jobs to the set of active jobs */

        if (IN_SET(mode, JOB_ISOLATE, JOB_FLUSH)) {

                /* When isolating first kill all installed jobs which
                 * aren't part of the new transaction */
                HASHMAP_FOREACH(j, m->jobs) {
                        assert(j->installed);

                        if (j->unit->ignore_on_isolate)
                                continue;

                        if (hashmap_contains(tr->jobs, j->unit))
                                continue;

                        /* Not invalidating recursively. Avoids triggering
                         * OnFailure= actions of dependent jobs. Also avoids
                         * invalidating our iterator. */
                        job_finish_and_invalidate(j, JOB_CANCELED, false, false);
                }
        }

        HASHMAP_FOREACH(j, tr->jobs) {
                /* Assume merged */
                assert(!j->transaction_prev);
                assert(!j->transaction_next);

                r = hashmap_ensure_put(&m->jobs, NULL, UINT32_TO_PTR(j->id), j);
                if (r < 0)
                        goto rollback;
        }

        while ((j = hashmap_steal_first(tr->jobs))) {
                Job *installed_job;

                /* Clean the job dependencies */
                transaction_unlink_job(tr, j, false);

                installed_job = job_install(j);
                if (installed_job != j) {
                        /* j has been merged into a previously installed job */
                        if (tr->anchor_job == j)
                                tr->anchor_job = installed_job;

                        hashmap_remove_value(m->jobs, UINT32_TO_PTR(j->id), j);
                        free_and_replace_full(j, installed_job, job_free);
                }

                job_add_to_run_queue(j);
                job_add_to_dbus_queue(j);
                job_start_timer(j, false);
                job_shutdown_magic(j);

                /* When 'affected' is specified, let's track all in it all jobs that were touched because of
                 * this transaction. */
                if (affected_jobs)
                        (void) set_put(affected_jobs, j);
        }

        return 0;

rollback:

        HASHMAP_FOREACH(j, tr->jobs)
                hashmap_remove_value(m->jobs, UINT32_TO_PTR(j->id), j);

        return r;
}

int transaction_activate(
                Transaction *tr,
                Manager *m,
                JobMode mode,
                Set *affected_jobs,
                sd_bus_error *e) {

        Job *j;
        int r;
        unsigned generation = 1;

        /* This applies the changes recorded in tr->jobs to the actual list of jobs, if possible. */

        assert(tr);
        assert(m);

        /* Reset the generation counter of all installed jobs. The detection of cycles
         * looks at installed jobs. If they had a non-zero generation from some previous
         * walk of the graph, the algorithm would break. */
        HASHMAP_FOREACH(j, m->jobs)
                j->generation = 0;

        /* First step: figure out which jobs matter */
        transaction_find_jobs_that_matter_to_anchor(tr->anchor_job, generation++);

        /* 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. */
        if (mode == JOB_FAIL)
                transaction_minimize_impact(tr);

        /* Third step: Drop redundant jobs */
        transaction_drop_redundant(tr);

        for (;;) {
                /* Fourth step: Let's remove unneeded jobs that might
                 * be lurking. */
                if (mode != JOB_ISOLATE)
                        transaction_collect_garbage(tr);

                /* Fifth step: verify order makes sense and correct
                 * cycles if necessary and possible */
                r = transaction_verify_order(tr, &generation, e);
                if (r >= 0)
                        break;
                if (r != -EAGAIN)
                        return log_warning_errno(r, "Requested transaction contains an unfixable cyclic ordering dependency: %s", bus_error_message(e, r));

                /* Let's see if the resulting transaction ordering
                 * graph is still cyclic... */
        }

        for (;;) {
                /* Sixth step: let's drop unmergeable entries if
                 * necessary and possible, merge entries we can
                 * merge */
                r = transaction_merge_jobs(tr, e);
                if (r >= 0)
                        break;
                if (r != -EAGAIN)
                        return log_warning_errno(r, "Requested transaction contains unmergeable jobs: %s", bus_error_message(e, r));

                /* Seventh step: an entry got dropped, let's garbage
                 * collect its dependencies. */
                if (mode != JOB_ISOLATE)
                        transaction_collect_garbage(tr);

                /* Let's see if the resulting transaction still has
                 * unmergeable entries ... */
        }

        /* Eights step: Drop redundant jobs again, if the merging now allows us to drop more. */
        transaction_drop_redundant(tr);

        /* Ninth step: check whether we can actually apply this */
        r = transaction_is_destructive(tr, mode, e);
        if (r < 0)
                return log_notice_errno(r, "Requested transaction contradicts existing jobs: %s", bus_error_message(e, r));

        /* Tenth step: apply changes */
        r = transaction_apply(tr, m, mode, affected_jobs);
        if (r < 0)
                return log_warning_errno(r, "Failed to apply transaction: %m");

        assert(hashmap_isempty(tr->jobs));

        /* Are there any jobs now? Then make sure we have the idle pipe around. We don't really care too much
         * whether this works or not, as the idle pipe is a feature for cosmetics, not actually useful for
         * anything beyond that. */
        if (!hashmap_isempty(m->jobs))
                (void) manager_allocate_idle_pipe(m);

        return 0;
}

static Job* transaction_add_one_job(Transaction *tr, JobType type, Unit *unit, bool *is_new) {
        Job *j, *f;

        assert(tr);
        assert(unit);

        /* Looks for an existing prospective job and returns that. If
         * it doesn't exist it is created and added to the prospective
         * jobs list. */

        f = hashmap_get(tr->jobs, unit);

        LIST_FOREACH(transaction, i, f) {
                assert(i->unit == unit);

                if (i->type == type) {
                        if (is_new)
                                *is_new = false;
                        return i;
                }
        }

        j = job_new(unit, type);
        if (!j)
                return NULL;

        j->irreversible = tr->irreversible;

        LIST_PREPEND(transaction, f, j);

        if (hashmap_replace(tr->jobs, unit, f) < 0) {
                LIST_REMOVE(transaction, f, j);
                job_free(j);
                return NULL;
        }

        if (is_new)
                *is_new = true;

        log_trace("Added job %s/%s to transaction.", unit->id, job_type_to_string(type));

        return j;
}

static void transaction_unlink_job(Transaction *tr, Job *j, bool delete_dependencies) {
        assert(tr);
        assert(j);

        if (j->transaction_prev)
                j->transaction_prev->transaction_next = j->transaction_next;
        else if (j->transaction_next)
                hashmap_replace(tr->jobs, j->unit, j->transaction_next);
        else
                hashmap_remove_value(tr->jobs, j->unit, j);

        if (j->transaction_next)
                j->transaction_next->transaction_prev = j->transaction_prev;

        j->transaction_prev = j->transaction_next = NULL;

        while (j->subject_list)
                job_dependency_free(j->subject_list);

        while (j->object_list) {
                Job *other = j->object_list->matters ? j->object_list->subject : NULL;

                job_dependency_free(j->object_list);

                if (other && delete_dependencies) {
                        log_unit_debug(other->unit,
                                       "Deleting job %s/%s as dependency of job %s/%s",
                                       other->unit->id, job_type_to_string(other->type),
                                       j->unit->id, job_type_to_string(j->type));
                        transaction_delete_job(tr, other, delete_dependencies);
                }
        }
}

void transaction_add_propagate_reload_jobs(
                Transaction *tr,
                Unit *unit,
                Job *by,
                TransactionAddFlags flags) {

        JobType nt;
        Unit *dep;
        int r;

        assert(tr);
        assert(unit);

        UNIT_FOREACH_DEPENDENCY(dep, unit, UNIT_ATOM_PROPAGATES_RELOAD_TO) {
                _cleanup_(sd_bus_error_free) sd_bus_error e = SD_BUS_ERROR_NULL;

                nt = job_type_collapse(JOB_TRY_RELOAD, dep);
                if (nt == JOB_NOP)
                        continue;

                r = transaction_add_job_and_dependencies(tr, nt, dep, by, flags, &e);
                if (r < 0)
                        log_unit_warning(dep,
                                         "Cannot add dependency reload job, ignoring: %s",
                                         bus_error_message(&e, r));
        }
}

static JobType job_type_propagate_stop_graceful(Job *j) {
        JobType type;

        if (!j)
                return JOB_STOP;

        type = JOB_STOP;

        LIST_FOREACH(transaction, i, j)
                switch (i->type) {

                case JOB_STOP:
                case JOB_RESTART:
                        /* Nothing to worry about, an appropriate job is in-place */
                        return JOB_NOP;

                case JOB_START:
                        /* This unit is pulled in by other dependency types in this transaction. We will run
                         * into job type conflict if we enqueue a stop job, so let's enqueue a restart job
                         * instead. */
                        type = JOB_RESTART;
                        break;

                default: /* We don't care about others */
                        ;

                }

        return type;
}

int transaction_add_job_and_dependencies(
                Transaction *tr,
                JobType type,
                Unit *unit,
                Job *by,
                TransactionAddFlags flags,
                sd_bus_error *e) {

        bool is_new;
        Job *ret;
        int r;

        assert(tr);
        assert(type >= 0);
        assert(type < _JOB_TYPE_MAX);
        assert(type < _JOB_TYPE_MAX_IN_TRANSACTION);
        assert(unit);

        /* Before adding jobs for this unit, let's ensure that its state has been loaded This matters when
         * jobs are spawned as part of coldplugging itself (see e. g. path_coldplug()).  This way, we
         * "recursively" coldplug units, ensuring that we do not look at state of not-yet-coldplugged
         * units. */
        if (MANAGER_IS_RELOADING(unit->manager))
                unit_coldplug(unit);

        if (by)
                log_trace("Pulling in %s/%s from %s/%s", unit->id, job_type_to_string(type), by->unit->id, job_type_to_string(by->type));

        /* Safety check that the unit is a valid state, i.e. not in UNIT_STUB or UNIT_MERGED which should only be set
         * temporarily. */
        if (!UNIT_IS_LOAD_COMPLETE(unit->load_state))
                return sd_bus_error_setf(e, BUS_ERROR_LOAD_FAILED, "Unit %s is not loaded properly.", unit->id);

        if (type != JOB_STOP) {
                r = bus_unit_validate_load_state(unit, e);
                /* The time-based cache allows new units to be started without daemon-reload, but if they are
                 * already referenced (because of dependencies or ordering) then we have to force a load of
                 * the fragment. As an optimization, check first if anything in the usual paths was modified
                 * since the last time the cache was loaded. Also check if the last time an attempt to load
                 * the unit was made was before the most recent cache refresh, so that we know we need to try
                 * again — even if the cache is current, it might have been updated in a different context
                 * before we had a chance to retry loading this particular unit.
                 *
                 * Given building up the transaction is a synchronous operation, attempt
                 * to load the unit immediately. */
                if (r < 0 && manager_unit_cache_should_retry_load(unit)) {
                        sd_bus_error_free(e);
                        unit->load_state = UNIT_STUB;
                        r = unit_load(unit);
                        if (r < 0 || unit->load_state == UNIT_STUB)
                                unit->load_state = UNIT_NOT_FOUND;
                        r = bus_unit_validate_load_state(unit, e);
                }
                if (r < 0)
                        return r;
        }

        if (!unit_job_is_applicable(unit, type))
                return sd_bus_error_setf(e, BUS_ERROR_JOB_TYPE_NOT_APPLICABLE,
                                         "Job type %s is not applicable for unit %s.",
                                         job_type_to_string(type), unit->id);

        if (type == JOB_START) {
                /* The hard concurrency limit for slice units we already enforce when a job is enqueued */
                Slice *slice = SLICE(UNIT_GET_SLICE(unit));
                if (slice && slice_concurrency_hard_max_reached(slice, unit))
                        return sd_bus_error_setf(
                                        e, BUS_ERROR_CONCURRENCY_LIMIT_REACHED,
                                        "Concurrency limit of the slice unit '%s' (or any of its parents) the unit '%s' is contained in has been reached, refusing start job.",
                                        UNIT(slice)->id, unit->id);
        }

        /* First add the job. */
        ret = transaction_add_one_job(tr, type, unit, &is_new);
        if (!ret)
                return -ENOMEM;

        if (FLAGS_SET(flags, TRANSACTION_IGNORE_ORDER))
                ret->ignore_order = true;

        /* Then, add a link to the job. */
        if (by) {
                if (!job_dependency_new(by, ret, FLAGS_SET(flags, TRANSACTION_MATTERS), FLAGS_SET(flags, TRANSACTION_CONFLICTS)))
                        return -ENOMEM;
        } else {
                /* If the job has no parent job, it is the anchor job. */
                assert(!tr->anchor_job);
                tr->anchor_job = ret;

                if (FLAGS_SET(flags, TRANSACTION_REENQUEUE_ANCHOR))
                        ret->refuse_late_merge = true;
        }

        if (!is_new || FLAGS_SET(flags, TRANSACTION_IGNORE_REQUIREMENTS) || type == JOB_NOP)
                return 0;

        _cleanup_set_free_ Set *following = NULL;
        Unit *dep;

        /* If we are following some other unit, make sure we add all dependencies of everybody following. */
        if (unit_following_set(ret->unit, &following) > 0)
                SET_FOREACH(dep, following) {
                        r = transaction_add_job_and_dependencies(tr, type, dep, ret, flags & TRANSACTION_IGNORE_ORDER, e);
                        if (r < 0) {
                                log_unit_full_errno(dep, r == -ERFKILL ? LOG_INFO : LOG_WARNING, r,
                                                    "Cannot add dependency job, ignoring: %s",
                                                    bus_error_message(e, r));
                                sd_bus_error_free(e);
                        }
                }

        /* Finally, recursively add in all dependencies. */
        if (IN_SET(type, JOB_START, JOB_RESTART)) {
                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PULL_IN_START) {
                        r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, TRANSACTION_MATTERS | (flags & TRANSACTION_IGNORE_ORDER), e);
                        if (r < 0) {
                                if (r != -EBADR) /* job type not applicable */
                                        goto fail;

                                sd_bus_error_free(e);
                        }
                }

                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PULL_IN_START_IGNORED) {
                        r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, flags & TRANSACTION_IGNORE_ORDER, e);
                        if (r < 0) {
                                /* unit masked, job type not applicable and unit not found are not considered
                                 * as errors. */
                                log_unit_full_errno(dep,
                                                    IN_SET(r, -ERFKILL, -EBADR, -ENOENT) ? LOG_DEBUG : LOG_WARNING,
                                                    r, "Cannot add dependency job, ignoring: %s",
                                                    bus_error_message(e, r));
                                sd_bus_error_free(e);
                        }
                }

                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PULL_IN_VERIFY) {
                        r = transaction_add_job_and_dependencies(tr, JOB_VERIFY_ACTIVE, dep, ret, TRANSACTION_MATTERS | (flags & TRANSACTION_IGNORE_ORDER), e);
                        if (r < 0) {
                                if (r != -EBADR) /* job type not applicable */
                                        goto fail;

                                sd_bus_error_free(e);
                        }
                }

                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PULL_IN_STOP) {
                        r = transaction_add_job_and_dependencies(tr, JOB_STOP, dep, ret, TRANSACTION_MATTERS | TRANSACTION_CONFLICTS | (flags & TRANSACTION_IGNORE_ORDER), e);
                        if (r < 0) {
                                if (r != -EBADR) /* job type not applicable */
                                        goto fail;

                                sd_bus_error_free(e);
                        }
                }

                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PULL_IN_STOP_IGNORED) {
                        r = transaction_add_job_and_dependencies(tr, JOB_STOP, dep, ret, flags & TRANSACTION_IGNORE_ORDER, e);
                        if (r < 0) {
                                log_unit_warning(dep,
                                                 "Cannot add dependency job, ignoring: %s",
                                                 bus_error_message(e, r));
                                sd_bus_error_free(e);
                        }
                }
        }

        if (IN_SET(type, JOB_RESTART, JOB_STOP) || (type == JOB_START && FLAGS_SET(flags, TRANSACTION_PROPAGATE_START_AS_RESTART))) {
                bool is_stop = type == JOB_STOP;

                UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PROPAGATE_STOP) {
                        /* We propagate RESTART only as TRY_RESTART, in order not to start dependencies that
                         * are not around. */
                        JobType nt;

                        nt = job_type_collapse(is_stop ? JOB_STOP : JOB_TRY_RESTART, dep);
                        if (nt == JOB_NOP)
                                continue;

                        r = transaction_add_job_and_dependencies(tr, nt, dep, ret, TRANSACTION_MATTERS | (flags & TRANSACTION_IGNORE_ORDER), e);
                        if (r < 0) {
                                if (r != -EBADR) /* job type not applicable */
                                        return r;

                                sd_bus_error_free(e);
                        }
                }

                /* Process UNIT_ATOM_PROPAGATE_STOP_GRACEFUL (PropagatesStopTo=) units. We need to wait until
                 * all other dependencies are processed, i.e. we're the anchor job or already in the recursion
                 * that handles it. */
                if (!by || FLAGS_SET(flags, TRANSACTION_PROCESS_PROPAGATE_STOP_GRACEFUL))
                        UNIT_FOREACH_DEPENDENCY(dep, ret->unit, UNIT_ATOM_PROPAGATE_STOP_GRACEFUL) {
                                JobType nt;
                                Job *j;

                                j = hashmap_get(tr->jobs, dep);
                                nt = job_type_propagate_stop_graceful(j);

                                if (nt == JOB_NOP)
                                        continue;

                                r = transaction_add_job_and_dependencies(tr, nt, dep, ret, TRANSACTION_MATTERS | (flags & TRANSACTION_IGNORE_ORDER) | TRANSACTION_PROCESS_PROPAGATE_STOP_GRACEFUL, e);
                                if (r < 0) {
                                        if (r != -EBADR) /* job type not applicable */
                                                return r;

                                        sd_bus_error_free(e);
                                }
                        }
        }

        if (type == JOB_RELOAD)
                transaction_add_propagate_reload_jobs(tr, ret->unit, ret, flags & TRANSACTION_IGNORE_ORDER);

        /* JOB_VERIFY_ACTIVE requires no dependency handling */

        return 0;

fail:
        /* Recursive call failed to add required jobs so let's drop top level job as well. */
        log_unit_debug_errno(unit, r, "Cannot add dependency job to transaction, deleting job %s/%s again: %s",
                             unit->id, job_type_to_string(type), bus_error_message(e, r));

        transaction_delete_job(tr, ret, /* delete_dependencies= */ false);
        return r;
}

static bool shall_stop_on_isolate(Transaction *tr, Unit *u) {
        assert(tr);
        assert(u);

        if (u->ignore_on_isolate)
                return false;

        /* Is there already something listed for this? */
        if (hashmap_contains(tr->jobs, u))
                return false;

        return true;
}

int transaction_add_isolate_jobs(Transaction *tr, Manager *m) {
        Unit *u;
        char *k;
        int r;

        assert(tr);
        assert(m);

        HASHMAP_FOREACH_KEY(u, k, m->units) {
                _cleanup_(sd_bus_error_free) sd_bus_error e = SD_BUS_ERROR_NULL;
                Unit *o;

                /* Ignore aliases */
                if (u->id != k)
                        continue;

                /* No need to stop inactive units */
                if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(u)) && !u->job)
                        continue;

                if (!shall_stop_on_isolate(tr, u))
                        continue;

                /* Keep units that are triggered by units we want to keep around. */
                bool keep = false;
                UNIT_FOREACH_DEPENDENCY(o, u, UNIT_ATOM_TRIGGERED_BY)
                        if (!shall_stop_on_isolate(tr, o)) {
                                keep = true;
                                break;
                        }
                if (keep)
                        continue;

                r = transaction_add_job_and_dependencies(tr, JOB_STOP, u, tr->anchor_job, TRANSACTION_MATTERS, &e);
                if (r < 0)
                        log_unit_warning_errno(u, r, "Cannot add isolate job, ignoring: %s", bus_error_message(&e, r));
        }

        return 0;
}

int transaction_add_triggering_jobs(Transaction *tr, Unit *u) {
        Unit *trigger;
        int r;

        assert(tr);
        assert(u);

        UNIT_FOREACH_DEPENDENCY(trigger, u, UNIT_ATOM_TRIGGERED_BY) {
                _cleanup_(sd_bus_error_free) sd_bus_error e = SD_BUS_ERROR_NULL;

                /* No need to stop inactive jobs */
                if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(trigger)) && !trigger->job)
                        continue;

                /* Is there already something listed for this? */
                if (hashmap_contains(tr->jobs, trigger))
                        continue;

                r = transaction_add_job_and_dependencies(tr, JOB_STOP, trigger, tr->anchor_job, TRANSACTION_MATTERS, &e);
                if (r < 0)
                        log_unit_warning_errno(u, r, "Cannot add triggered by job, ignoring: %s", bus_error_message(&e, r));
        }

        return 0;
}

Transaction *transaction_new(bool irreversible) {
        Transaction *tr;

        tr = new0(Transaction, 1);
        if (!tr)
                return NULL;

        tr->jobs = hashmap_new(NULL);
        if (!tr->jobs)
                return mfree(tr);

        tr->irreversible = irreversible;

        return tr;
}

Transaction *transaction_free(Transaction *tr) {
        if (!tr)
                return NULL;

        assert(hashmap_isempty(tr->jobs));
        hashmap_free(tr->jobs);

        return mfree(tr);
}

Transaction *transaction_abort_and_free(Transaction *tr) {
        if (!tr)
                return NULL;

        transaction_abort(tr);

        return transaction_free(tr);
}

systemd / systemd / 14630481637

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