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54a7b863dd
systemd/src/job.c
Michal Schmidt 563ba9ea6e manager: fix a crash in isolating 
HASHMAP_FOREACH is safe against the removal of the current entry, but
not against the removal of other entries. job_finish_and_invalidate()
can recursively remove other entries.

It triggered an assertion failure:
  Assertion 'j->installed' failed at src/manager.c:1218, function
  transaction_apply(). Aborting.

Fix the crash by iterating from the beginning when there is a
possibility that the iterator could be invalid.

It is O(n^2) in the worst case, but that's better than a crash.

https://bugzilla.redhat.com/show_bug.cgi?id=717325
2011-10-17 11:29:27 +02:00

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <errno.h>
#include <sys/timerfd.h>
#include <sys/epoll.h>
#include "set.h"
#include "unit.h"
#include "macro.h"
#include "strv.h"
#include "load-fragment.h"
#include "load-dropin.h"
#include "log.h"
#include "dbus-job.h"
Job* job_new(Manager *m, JobType type, Unit *unit) {
Job *j;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(unit);
if (!(j = new0(Job, 1)))
return NULL;
j->manager = m;
j->id = m->current_job_id++;
j->type = type;
j->unit = unit;
j->timer_watch.type = WATCH_INVALID;
/* We don't link it here, that's what job_dependency() is for */
return j;
}
void job_free(Job *j) {
assert(j);
/* Detach from next 'bigger' objects */
if (j->installed) {
bus_job_send_removed_signal(j);
if (j->unit->meta.job == j) {
j->unit->meta.job = NULL;
unit_add_to_gc_queue(j->unit);
}
hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
j->installed = false;
}
/* Detach from next 'smaller' objects */
manager_transaction_unlink_job(j->manager, j, true);
if (j->in_run_queue)
LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
if (j->in_dbus_queue)
LIST_REMOVE(Job, dbus_queue, j->manager->dbus_job_queue, j);
if (j->timer_watch.type != WATCH_INVALID) {
assert(j->timer_watch.type == WATCH_JOB_TIMER);
assert(j->timer_watch.data.job == j);
assert(j->timer_watch.fd >= 0);
assert_se(epoll_ctl(j->manager->epoll_fd, EPOLL_CTL_DEL, j->timer_watch.fd, NULL) >= 0);
close_nointr_nofail(j->timer_watch.fd);
}
free(j->bus_client);
free(j);
}
JobDependency* job_dependency_new(Job *subject, Job *object, bool matters, bool conflicts) {
JobDependency *l;
assert(object);
/* 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
* explicitly asked for) is the requester. */
if (!(l = new0(JobDependency, 1)))
return NULL;
l->subject = subject;
l->object = object;
l->matters = matters;
l->conflicts = conflicts;
if (subject)
LIST_PREPEND(JobDependency, subject, subject->subject_list, l);
else
LIST_PREPEND(JobDependency, subject, object->manager->transaction_anchor, l);
LIST_PREPEND(JobDependency, object, object->object_list, l);
return l;
}
void job_dependency_free(JobDependency *l) {
assert(l);
if (l->subject)
LIST_REMOVE(JobDependency, subject, l->subject->subject_list, l);
else
LIST_REMOVE(JobDependency, subject, l->object->manager->transaction_anchor, l);
LIST_REMOVE(JobDependency, object, l->object->object_list, l);
free(l);
}
void job_dump(Job *j, FILE*f, const char *prefix) {
assert(j);
assert(f);
if (!prefix)
prefix = "";
fprintf(f,
"%s-> Job %u:\n"
"%s\tAction: %s -> %s\n"
"%s\tState: %s\n"
"%s\tForced: %s\n",
prefix, j->id,
prefix, j->unit->meta.id, job_type_to_string(j->type),
prefix, job_state_to_string(j->state),
prefix, yes_no(j->override));
}
bool job_is_anchor(Job *j) {
JobDependency *l;
assert(j);
LIST_FOREACH(object, l, j->object_list)
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_type_is_redundant(JobType a, UnitActiveState b) {
switch (a) {
case JOB_START:
return
b == UNIT_ACTIVE ||
b == UNIT_RELOADING;
case JOB_STOP:
return
b == UNIT_INACTIVE ||
b == UNIT_FAILED;
case JOB_VERIFY_ACTIVE:
return
b == UNIT_ACTIVE ||
b == UNIT_RELOADING;
case JOB_RELOAD:
return
b == UNIT_RELOADING;
case JOB_RELOAD_OR_START:
return
b == UNIT_ACTIVATING ||
b == UNIT_RELOADING;
case JOB_RESTART:
return
b == UNIT_ACTIVATING;
case JOB_TRY_RESTART:
return
b == UNIT_ACTIVATING;
default:
assert_not_reached("Invalid job type");
}
}
bool job_is_runnable(Job *j) {
Iterator i;
Unit *other;
assert(j);
assert(j->installed);
/* Checks whether there is any job running for the units 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. */
/* First check if there is an override */
if (j->ignore_order)
return true;
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->unit->meta.dependencies[UNIT_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->unit->meta.dependencies[UNIT_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;
uint32_t id;
Manager *m;
assert(j);
assert(j->installed);
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;
job_add_to_dbus_queue(j);
/* While we execute this operation the job might go away (for
* example: because it is replaced by a new, conflicting
* job.) To make sure we don't access a freed job later on we
* store the id here, so that we can verify the job is still
* valid. */
id = j->id;
m = j->manager;
switch (j->type) {
case JOB_START:
r = unit_start(j->unit);
/* If this unit cannot be started, then simply
* wait */
if (r == -EBADR)
r = 0;
break;
case JOB_VERIFY_ACTIVE: {
UnitActiveState t = unit_active_state(j->unit);
if (UNIT_IS_ACTIVE_OR_RELOADING(t))
r = -EALREADY;
else if (t == UNIT_ACTIVATING)
r = -EAGAIN;
else
r = -ENOEXEC;
break;
}
case JOB_STOP:
r = unit_stop(j->unit);
/* If this unit cannot stopped, then simply
* wait. */
if (r == -EBADR)
r = 0;
break;
case JOB_RELOAD:
r = unit_reload(j->unit);
break;
case JOB_RELOAD_OR_START:
if (unit_active_state(j->unit) == UNIT_ACTIVE) {
j->type = JOB_RELOAD;
r = unit_reload(j->unit);
} else {
j->type = JOB_START;
r = unit_start(j->unit);
if (r == -EBADR)
r = 0;
}
break;
case JOB_RESTART: {
UnitActiveState t = unit_active_state(j->unit);
if (t == UNIT_INACTIVE || t == UNIT_FAILED || t == UNIT_ACTIVATING) {
j->type = JOB_START;
r = unit_start(j->unit);
} else
r = unit_stop(j->unit);
break;
}
case JOB_TRY_RESTART: {
UnitActiveState t = unit_active_state(j->unit);
if (t == UNIT_INACTIVE || t == UNIT_FAILED || t == UNIT_DEACTIVATING)
r = -ENOEXEC;
else if (t == UNIT_ACTIVATING) {
j->type = JOB_START;
r = unit_start(j->unit);
} else {
j->type = JOB_RESTART;
r = unit_stop(j->unit);
}
break;
}
default:
assert_not_reached("Unknown job type");
}
if ((j = manager_get_job(m, id))) {
if (r == -EALREADY)
r = job_finish_and_invalidate(j, JOB_DONE);
else if (r == -ENOEXEC)
r = job_finish_and_invalidate(j, JOB_SKIPPED);
else if (r == -EAGAIN)
j->state = JOB_WAITING;
else if (r < 0)
r = job_finish_and_invalidate(j, JOB_FAILED);
}
return r;
}
static void job_print_status_message(Unit *u, JobType t, JobResult result) {
assert(u);
if (t == JOB_START) {
switch (result) {
case JOB_DONE:
unit_status_printf(u, "Started %s.\n", unit_description(u));
break;
case JOB_FAILED:
unit_status_printf(u, "Starting %s " ANSI_HIGHLIGHT_ON "failed" ANSI_HIGHLIGHT_OFF ", see 'systemctl status %s' for details.\n", unit_description(u), u->meta.id);
break;
case JOB_DEPENDENCY:
unit_status_printf(u, "Starting %s " ANSI_HIGHLIGHT_ON "aborted" ANSI_HIGHLIGHT_OFF " because a dependency failed.\n", unit_description(u));
break;
case JOB_TIMEOUT:
unit_status_printf(u, "Starting %s " ANSI_HIGHLIGHT_ON "timed out" ANSI_HIGHLIGHT_OFF ".\n", unit_description(u), u->meta.id);
break;
default:
;
}
} else if (t == JOB_STOP) {
switch (result) {
case JOB_TIMEOUT:
unit_status_printf(u, "Stopping %s " ANSI_HIGHLIGHT_ON "timed out" ANSI_HIGHLIGHT_OFF ".\n", unit_description(u), u->meta.id);
break;
case JOB_DONE:
case JOB_FAILED:
unit_status_printf(u, "Stopped %s.\n", unit_description(u));
break;
default:
;
}
}
}
int job_finish_and_invalidate(Job *j, JobResult result) {
Unit *u;
Unit *other;
JobType t;
Iterator i;
bool recursed = false;
assert(j);
assert(j->installed);
job_add_to_dbus_queue(j);
/* Patch restart jobs so that they become normal start jobs */
if (result == JOB_DONE && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
log_debug("Converting job %s/%s -> %s/%s",
j->unit->meta.id, job_type_to_string(j->type),
j->unit->meta.id, job_type_to_string(JOB_START));
j->state = JOB_WAITING;
j->type = JOB_START;
job_add_to_run_queue(j);
u = j->unit;
goto finish;
}
j->result = result;
log_debug("Job %s/%s finished, result=%s", j->unit->meta.id, job_type_to_string(j->type), job_result_to_string(result));
if (result == JOB_FAILED)
j->manager->n_failed_jobs ++;
u = j->unit;
t = j->type;
job_free(j);
job_print_status_message(u, t, result);
/* Fail depending jobs on failure */
if (result != JOB_DONE) {
if (t == JOB_START ||
t == JOB_VERIFY_ACTIVE ||
t == JOB_RELOAD_OR_START) {
SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
if (other->meta.job &&
(other->meta.job->type == JOB_START ||
other->meta.job->type == JOB_VERIFY_ACTIVE ||
other->meta.job->type == JOB_RELOAD_OR_START)) {
job_finish_and_invalidate(other->meta.job, JOB_DEPENDENCY);
recursed = true;
}
SET_FOREACH(other, u->meta.dependencies[UNIT_BOUND_BY], i)
if (other->meta.job &&
(other->meta.job->type == JOB_START ||
other->meta.job->type == JOB_VERIFY_ACTIVE ||
other->meta.job->type == JOB_RELOAD_OR_START)) {
job_finish_and_invalidate(other->meta.job, JOB_DEPENDENCY);
recursed = true;
}
SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY_OVERRIDABLE], i)
if (other->meta.job &&
!other->meta.job->override &&
(other->meta.job->type == JOB_START ||
other->meta.job->type == JOB_VERIFY_ACTIVE ||
other->meta.job->type == JOB_RELOAD_OR_START)) {
job_finish_and_invalidate(other->meta.job, JOB_DEPENDENCY);
recursed = true;
}
} else if (t == JOB_STOP) {
SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTED_BY], i)
if (other->meta.job &&
(other->meta.job->type == JOB_START ||
other->meta.job->type == JOB_VERIFY_ACTIVE ||
other->meta.job->type == JOB_RELOAD_OR_START)) {
job_finish_and_invalidate(other->meta.job, JOB_DEPENDENCY);
recursed = true;
}
}
}
/* Trigger OnFailure dependencies that are not generated by
* the unit itself. We don't tread JOB_CANCELED as failure in
* this context. And JOB_FAILURE is already handled by the
* unit itself. */
if (result == JOB_TIMEOUT || result == JOB_DEPENDENCY) {
log_notice("Job %s/%s failed with result '%s'.",
u->meta.id,
job_type_to_string(t),
job_result_to_string(result));
unit_trigger_on_failure(u);
}
finish:
/* Try to start the next jobs that can be started */
SET_FOREACH(other, u->meta.dependencies[UNIT_AFTER], i)
if (other->meta.job)
job_add_to_run_queue(other->meta.job);
SET_FOREACH(other, u->meta.dependencies[UNIT_BEFORE], i)
if (other->meta.job)
job_add_to_run_queue(other->meta.job);
manager_check_finished(u->meta.manager);
return recursed;
}
int job_start_timer(Job *j) {
struct itimerspec its;
struct epoll_event ev;
int fd, r;
assert(j);
if (j->unit->meta.job_timeout <= 0 ||
j->timer_watch.type == WATCH_JOB_TIMER)
return 0;
assert(j->timer_watch.type == WATCH_INVALID);
if ((fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) < 0) {
r = -errno;
goto fail;
}
zero(its);
timespec_store(&its.it_value, j->unit->meta.job_timeout);
if (timerfd_settime(fd, 0, &its, NULL) < 0) {
r = -errno;
goto fail;
}
zero(ev);
ev.data.ptr = &j->timer_watch;
ev.events = EPOLLIN;
if (epoll_ctl(j->manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
r = -errno;
goto fail;
}
j->timer_watch.type = WATCH_JOB_TIMER;
j->timer_watch.fd = fd;
j->timer_watch.data.job = j;
return 0;
fail:
if (fd >= 0)
close_nointr_nofail(fd);
return r;
}
void job_add_to_run_queue(Job *j) {
assert(j);
assert(j->installed);
if (j->in_run_queue)
return;
LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
j->in_run_queue = true;
}
void job_add_to_dbus_queue(Job *j) {
assert(j);
assert(j->installed);
if (j->in_dbus_queue)
return;
/* We don't check if anybody is subscribed here, since this
* job might just have been created and not yet assigned to a
* connection/client. */
LIST_PREPEND(Job, dbus_queue, j->manager->dbus_job_queue, j);
j->in_dbus_queue = true;
}
char *job_dbus_path(Job *j) {
char *p;
assert(j);
if (asprintf(&p, "/org/freedesktop/systemd1/job/%lu", (unsigned long) j->id) < 0)
return NULL;
return p;
}
void job_timer_event(Job *j, uint64_t n_elapsed, Watch *w) {
assert(j);
assert(w == &j->timer_watch);
log_warning("Job %s/%s timed out.", j->unit->meta.id, job_type_to_string(j->type));
job_finish_and_invalidate(j, JOB_TIMEOUT);
}
static const char* const job_state_table[_JOB_STATE_MAX] = {
[JOB_WAITING] = "waiting",
[JOB_RUNNING] = "running"
};
DEFINE_STRING_TABLE_LOOKUP(job_state, JobState);
static const char* const job_type_table[_JOB_TYPE_MAX] = {
[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",
};
DEFINE_STRING_TABLE_LOOKUP(job_type, JobType);
static const char* const job_mode_table[_JOB_MODE_MAX] = {
[JOB_FAIL] = "fail",
[JOB_REPLACE] = "replace",
[JOB_ISOLATE] = "isolate",
[JOB_IGNORE_DEPENDENCIES] = "ignore-dependencies",
[JOB_IGNORE_REQUIREMENTS] = "ignore-requirements"
};
DEFINE_STRING_TABLE_LOOKUP(job_mode, JobMode);
static const char* const job_result_table[_JOB_RESULT_MAX] = {
[JOB_DONE] = "done",
[JOB_CANCELED] = "canceled",
[JOB_TIMEOUT] = "timeout",
[JOB_FAILED] = "failed",
[JOB_DEPENDENCY] = "dependency",
[JOB_SKIPPED] = "skipped"
};
DEFINE_STRING_TABLE_LOOKUP(job_result, JobResult);
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