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systemd/manager.c
Lennart Poettering 05e343b704 service: optionally, trie dbus name cycle to service cycle
2010-04-15 23:16:16 +02:00

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/*-*- Mode: C; c-basic-offset: 8 -*-*/
/***
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 <string.h>
#include <sys/epoll.h>
#include <signal.h>
#include <sys/signalfd.h>
#include <sys/wait.h>
#include <unistd.h>
#include <utmpx.h>
#include <sys/poll.h>
#include <sys/reboot.h>
#include <sys/ioctl.h>
#include <linux/kd.h>
#include <libcgroup.h>
#include <termios.h>
#include <fcntl.h>
#include "manager.h"
#include "hashmap.h"
#include "macro.h"
#include "strv.h"
#include "log.h"
#include "util.h"
#include "ratelimit.h"
#include "cgroup.h"
#include "mount-setup.h"
#include "utmp-wtmp.h"
#include "unit-name.h"
static int enable_special_signals(Manager *m) {
char fd;
assert(m);
/* Enable that we get SIGINT on control-alt-del */
if (reboot(RB_DISABLE_CAD) < 0)
log_warning("Failed to enable ctrl-alt-del handling: %m");
if ((fd = open_terminal("/dev/tty0", O_RDWR)) < 0)
log_warning("Failed to open /dev/tty0: %m");
else {
/* Enable that we get SIGWINCH on kbrequest */
if (ioctl(fd, KDSIGACCEPT, SIGWINCH) < 0)
log_warning("Failed to enable kbrequest handling: %s", strerror(errno));
close_nointr_nofail(fd);
}
return 0;
}
static int manager_setup_signals(Manager *m) {
sigset_t mask;
struct epoll_event ev;
struct sigaction sa;
assert(m);
/* We are not interested in SIGSTOP and friends. */
zero(sa);
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
assert_se(sigemptyset(&mask) == 0);
assert_se(sigaddset(&mask, SIGCHLD) == 0);
assert_se(sigaddset(&mask, SIGTERM) == 0);
assert_se(sigaddset(&mask, SIGHUP) == 0);
assert_se(sigaddset(&mask, SIGUSR1) == 0);
assert_se(sigaddset(&mask, SIGUSR2) == 0);
assert_se(sigaddset(&mask, SIGINT) == 0); /* Kernel sends us this on control-alt-del */
assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
assert_se(sigaddset(&mask, SIGPWR) == 0); /* Some kernel drivers and upsd send us this on power failure */
assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
m->signal_watch.type = WATCH_SIGNAL;
if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
return -errno;
zero(ev);
ev.events = EPOLLIN;
ev.data.ptr = &m->signal_watch;
if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
return -errno;
if (m->running_as == MANAGER_INIT)
return enable_special_signals(m);
return 0;
}
static char** session_dirs(void) {
const char *home, *e;
char *config_home = NULL, *data_home = NULL;
char **config_dirs = NULL, **data_dirs = NULL;
char **r = NULL, **t;
/* Implement the mechanisms defined in
*
* http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html
*
* We look in both the config and the data dirs because we
* want to encourage that distributors ship their unit files
* as data, and allow overriding as configuration.
*/
home = getenv("HOME");
if ((e = getenv("XDG_CONFIG_HOME"))) {
if (asprintf(&config_home, "%s/systemd/session", e) < 0)
goto fail;
} else if (home) {
if (asprintf(&config_home, "%s/.config/systemd/session", home) < 0)
goto fail;
}
if ((e = getenv("XDG_CONFIG_DIRS")))
config_dirs = strv_split(e, ":");
else
config_dirs = strv_new("/etc/xdg", NULL);
if (!config_dirs)
goto fail;
if ((e = getenv("XDG_DATA_HOME"))) {
if (asprintf(&data_home, "%s/systemd/session", e) < 0)
goto fail;
} else if (home) {
if (asprintf(&data_home, "%s/.local/share/systemd/session", home) < 0)
goto fail;
}
if ((e = getenv("XDG_DATA_DIRS")))
data_dirs = strv_split(e, ":");
else
data_dirs = strv_new("/usr/local/share", "/usr/share", NULL);
if (!data_dirs)
goto fail;
/* Now merge everything we found. */
if (config_home) {
if (!(t = strv_append(r, config_home)))
goto fail;
strv_free(r);
r = t;
}
if (!(t = strv_merge_concat(r, config_dirs, "/systemd/session")))
goto finish;
strv_free(r);
r = t;
if (!(t = strv_append(r, SESSION_CONFIG_UNIT_PATH)))
goto fail;
strv_free(r);
r = t;
if (data_home) {
if (!(t = strv_append(r, data_home)))
goto fail;
strv_free(r);
r = t;
}
if (!(t = strv_merge_concat(r, data_dirs, "/systemd/session")))
goto fail;
strv_free(r);
r = t;
if (!(t = strv_append(r, SESSION_DATA_UNIT_PATH)))
goto fail;
strv_free(r);
r = t;
if (!strv_path_make_absolute_cwd(r))
goto fail;
finish:
free(config_home);
strv_free(config_dirs);
free(data_home);
strv_free(data_dirs);
return r;
fail:
strv_free(r);
r = NULL;
goto finish;
}
static int manager_find_paths(Manager *m) {
const char *e;
char *t;
assert(m);
/* First priority is whatever has been passed to us via env
* vars */
if ((e = getenv("SYSTEMD_UNIT_PATH")))
if (!(m->unit_path = split_path_and_make_absolute(e)))
return -ENOMEM;
if (strv_isempty(m->unit_path)) {
/* Nothing is set, so let's figure something out. */
strv_free(m->unit_path);
if (m->running_as == MANAGER_SESSION) {
if (!(m->unit_path = session_dirs()))
return -ENOMEM;
} else
if (!(m->unit_path = strv_new(
SYSTEM_CONFIG_UNIT_PATH, /* /etc/systemd/system/ */
SYSTEM_DATA_UNIT_PATH, /* /lib/systemd/system/ */
NULL)))
return -ENOMEM;
}
if (m->running_as == MANAGER_INIT) {
/* /etc/init.d/ compativility does not matter to users */
if ((e = getenv("SYSTEMD_SYSVINIT_PATH")))
if (!(m->sysvinit_path = split_path_and_make_absolute(e)))
return -ENOMEM;
if (strv_isempty(m->sysvinit_path)) {
strv_free(m->sysvinit_path);
if (!(m->sysvinit_path = strv_new(
SYSTEM_SYSVINIT_PATH, /* /etc/init.d/ */
NULL)))
return -ENOMEM;
}
if ((e = getenv("SYSTEMD_SYSVRCND_PATH")))
if (!(m->sysvrcnd_path = split_path_and_make_absolute(e)))
return -ENOMEM;
if (strv_isempty(m->sysvrcnd_path)) {
strv_free(m->sysvrcnd_path);
if (!(m->sysvrcnd_path = strv_new(
SYSTEM_SYSVRCND_PATH, /* /etc/rcN.d/ */
NULL)))
return -ENOMEM;
}
}
strv_uniq(m->unit_path);
strv_uniq(m->sysvinit_path);
strv_uniq(m->sysvrcnd_path);
assert(!strv_isempty(m->unit_path));
if (!(t = strv_join(m->unit_path, "\n\t")))
return -ENOMEM;
log_debug("Looking for unit files in:\n\t%s", t);
free(t);
if (!strv_isempty(m->sysvinit_path)) {
if (!(t = strv_join(m->sysvinit_path, "\n\t")))
return -ENOMEM;
log_debug("Looking for SysV init scripts in:\n\t%s", t);
free(t);
} else
log_debug("Ignoring SysV init scripts.");
if (!strv_isempty(m->sysvrcnd_path)) {
if (!(t = strv_join(m->sysvrcnd_path, "\n\t")))
return -ENOMEM;
log_debug("Looking for SysV rcN.d links in:\n\t%s", t);
free(t);
} else
log_debug("Ignoring SysV rcN.d links.");
return 0;
}
int manager_new(ManagerRunningAs running_as, bool confirm_spawn, Manager **_m) {
Manager *m;
int r = -ENOMEM;
assert(_m);
assert(running_as >= 0);
assert(running_as < _MANAGER_RUNNING_AS_MAX);
if (!(m = new0(Manager, 1)))
return -ENOMEM;
m->boot_timestamp = now(CLOCK_REALTIME);
m->running_as = running_as;
m->confirm_spawn = confirm_spawn;
m->name_data_slot = -1;
m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
goto fail;
if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
goto fail;
if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
goto fail;
if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
goto fail;
if (!(m->cgroup_bondings = hashmap_new(string_hash_func, string_compare_func)))
goto fail;
if (!(m->watch_bus = hashmap_new(string_hash_func, string_compare_func)))
goto fail;
if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
goto fail;
if ((r = manager_find_paths(m)) < 0)
goto fail;
if ((r = manager_setup_signals(m)) < 0)
goto fail;
if ((r = manager_setup_cgroup(m)) < 0)
goto fail;
/* Try to connect to the busses, if possible. */
if ((r = bus_init_system(m)) < 0 ||
(r = bus_init_api(m)) < 0)
goto fail;
*_m = m;
return 0;
fail:
manager_free(m);
return r;
}
static unsigned manager_dispatch_cleanup_queue(Manager *m) {
Meta *meta;
unsigned n = 0;
assert(m);
while ((meta = m->cleanup_queue)) {
assert(meta->in_cleanup_queue);
unit_free(UNIT(meta));
n++;
}
return n;
}
void manager_free(Manager *m) {
UnitType c;
Unit *u;
Job *j;
assert(m);
while ((j = hashmap_first(m->transaction_jobs)))
job_free(j);
while ((u = hashmap_first(m->units)))
unit_free(u);
manager_dispatch_cleanup_queue(m);
for (c = 0; c < _UNIT_TYPE_MAX; c++)
if (unit_vtable[c]->shutdown)
unit_vtable[c]->shutdown(m);
manager_shutdown_cgroup(m);
bus_done_api(m);
bus_done_system(m);
hashmap_free(m->units);
hashmap_free(m->jobs);
hashmap_free(m->transaction_jobs);
hashmap_free(m->watch_pids);
hashmap_free(m->watch_bus);
if (m->epoll_fd >= 0)
close_nointr(m->epoll_fd);
if (m->signal_watch.fd >= 0)
close_nointr(m->signal_watch.fd);
strv_free(m->unit_path);
strv_free(m->sysvinit_path);
strv_free(m->sysvrcnd_path);
free(m->cgroup_controller);
free(m->cgroup_hierarchy);
assert(hashmap_isempty(m->cgroup_bondings));
hashmap_free(m->cgroup_bondings);
free(m);
}
int manager_coldplug(Manager *m) {
int r;
UnitType c;
Iterator i;
Unit *u;
char *k;
assert(m);
/* First, let's ask every type to load all units from
* disk/kernel that it might know */
for (c = 0; c < _UNIT_TYPE_MAX; c++)
if (unit_vtable[c]->enumerate)
if ((r = unit_vtable[c]->enumerate(m)) < 0)
return r;
manager_dispatch_load_queue(m);
/* Then, let's set up their initial state. */
HASHMAP_FOREACH_KEY(u, k, m->units, i) {
/* ignore aliases */
if (u->meta.id != k)
continue;
if (UNIT_VTABLE(u)->coldplug)
if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
return r;
}
/* Now that the initial devices are available, let's see if we
* can write the utmp file */
manager_write_utmp_reboot(m);
return 0;
}
static void transaction_delete_job(Manager *m, Job *j, bool delete_dependencies) {
assert(m);
assert(j);
/* Deletes one job from the transaction */
manager_transaction_unlink_job(m, j, delete_dependencies);
if (!j->installed)
job_free(j);
}
static void transaction_delete_unit(Manager *m, Unit *u) {
Job *j;
/* Deletes all jobs associated with a certain unit from the
* transaction */
while ((j = hashmap_get(m->transaction_jobs, u)))
transaction_delete_job(m, j, true);
}
static void transaction_clean_dependencies(Manager *m) {
Iterator i;
Job *j;
assert(m);
/* Drops all dependencies of all installed jobs */
HASHMAP_FOREACH(j, m->jobs, i) {
while (j->subject_list)
job_dependency_free(j->subject_list);
while (j->object_list)
job_dependency_free(j->object_list);
}
assert(!m->transaction_anchor);
}
static void transaction_abort(Manager *m) {
Job *j;
assert(m);
while ((j = hashmap_first(m->transaction_jobs)))
if (j->installed)
transaction_delete_job(m, j, true);
else
job_free(j);
assert(hashmap_isempty(m->transaction_jobs));
transaction_clean_dependencies(m);
}
static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
JobDependency *l;
assert(m);
/* 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. */
if (j)
l = j->subject_list;
else
l = m->transaction_anchor;
LIST_FOREACH(subject, l, l) {
/* This link does not matter */
if (!l->matters)
continue;
/* This unit has already been marked */
if (l->object->generation == generation)
continue;
l->object->matters_to_anchor = true;
l->object->generation = generation;
transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
}
}
static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
JobDependency *l, *last;
assert(j);
assert(other);
assert(j->unit == other->unit);
assert(!j->installed);
/* Merges 'other' into 'j' and then deletes j. */
j->type = t;
j->state = JOB_WAITING;
j->override = j->override || other->override;
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(m, other, true);
}
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 */
LIST_FOREACH(transaction, j, j)
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)
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("Trying to fix job merging by deleting job %s/%s", d->unit->meta.id, job_type_to_string(d->type));
transaction_delete_job(m, d, true);
return 0;
}
return -EINVAL;
}
static int transaction_merge_jobs(Manager *m) {
Job *j;
Iterator i;
int r;
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, i) {
JobType t;
Job *k;
t = j->type;
LIST_FOREACH(transaction, k, j->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, i) {
JobType t = j->type;
Job *k;
/* Merge all transactions */
LIST_FOREACH(transaction, k, j->transaction_next)
assert_se(job_type_merge(&t, k->type) == 0);
/* If an active job is mergeable, merge it too */
if (j->unit->meta.job)
job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
while ((k = j->transaction_next)) {
if (j->installed) {
transaction_merge_and_delete_job(m, k, j, t);
j = k;
} else
transaction_merge_and_delete_job(m, j, k, t);
}
assert(!j->transaction_next);
assert(!j->transaction_prev);
}
return 0;
}
static void transaction_drop_redundant(Manager *m) {
bool again;
assert(m);
/* Goes through the transaction and removes all jobs that are
* a noop */
do {
Job *j;
Iterator i;
again = false;
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
bool changes_something = false;
Job *k;
LIST_FOREACH(transaction, k, j) {
if (!job_is_anchor(k) &&
job_type_is_redundant(k->type, unit_active_state(k->unit)))
continue;
changes_something = true;
break;
}
if (changes_something)
continue;
log_debug("Found redundant job %s/%s, dropping.", j->unit->meta.id, job_type_to_string(j->type));
transaction_delete_job(m, j, false);
again = true;
break;
}
} while (again);
}
static bool unit_matters_to_anchor(Unit *u, Job *j) {
assert(u);
assert(!j->transaction_prev);
/* Checks whether at least one of the jobs for this unit
* matters to the anchor. */
LIST_FOREACH(transaction, j, j)
if (j->matters_to_anchor)
return true;
return false;
}
static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
Iterator i;
Unit *u;
int r;
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. We use the marker to find our way back,
* since smart how we are we stored our way back in
* there. */
log_debug("Found ordering cycle on %s/%s", j->unit->meta.id, job_type_to_string(j->type));
for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
log_debug("Walked on cycle path to %s/%s", k->unit->meta.id, job_type_to_string(k->type));
if (!k->installed &&
!unit_matters_to_anchor(k->unit, k)) {
/* Ok, we can drop this one, so let's
* do so. */
log_debug("Breaking order cycle by deleting job %s/%s", k->unit->meta.id, job_type_to_string(k->type));
transaction_delete_unit(m, k->unit);
return -EAGAIN;
}
/* Check if this in fact was the beginning of
* the cycle */
if (k == j)
break;
}
log_debug("Unable to break cycle");
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 bidirectional, and
* hence can ignore UNIT_AFTER */
SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
Job *o;
/* Is there a job for this unit? */
if (!(o = hashmap_get(m->transaction_jobs, u)))
/* Ok, there is no job for this in the
* transaction, but maybe there is already one
* running? */
if (!(o = u->meta.job))
continue;
if ((r = transaction_verify_order_one(m, o, j, generation)) < 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(Manager *m, unsigned *generation) {
Job *j;
int r;
Iterator i;
assert(m);
assert(generation);
/* Check if the ordering graph is cyclic. If it is, try to fix
* that up by dropping one of the jobs. */
HASHMAP_FOREACH(j, m->transaction_jobs, i)
if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
return r;
return 0;
}
static void transaction_collect_garbage(Manager *m) {
bool again;
assert(m);
/* Drop jobs that are not required by any other job */
do {
Iterator i;
Job *j;
again = false;
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
if (j->object_list)
continue;
log_debug("Garbage collecting job %s/%s", j->unit->meta.id, job_type_to_string(j->type));
transaction_delete_job(m, j, true);
again = true;
break;
}
} while (again);
}
static int transaction_is_destructive(Manager *m, JobMode mode) {
Iterator i;
Job *j;
assert(m);
/* Checks whether applying this transaction means that
* existing jobs would be replaced */
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
/* Assume merged */
assert(!j->transaction_prev);
assert(!j->transaction_next);
if (j->unit->meta.job &&
j->unit->meta.job != j &&
!job_type_is_superset(j->type, j->unit->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;
Iterator i;
again = false;
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
LIST_FOREACH(transaction, j, j) {
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->meta.job && job_type_is_conflicting(j->type, j->unit->meta.job->state);
if (!stops_running_service && !changes_existing_job)
continue;
if (stops_running_service)
log_debug("%s/%s would stop a running service.", j->unit->meta.id, job_type_to_string(j->type));
if (changes_existing_job)
log_debug("%s/%s would change existing job.", j->unit->meta.id, job_type_to_string(j->type));
/* Ok, let's get rid of this */
log_debug("Deleting %s/%s to minimize impact.", j->unit->meta.id, job_type_to_string(j->type));
transaction_delete_job(m, j, true);
again = true;
break;
}
if (again)
break;
}
} while (again);
}
static int transaction_apply(Manager *m, JobMode mode) {
Iterator i;
Job *j;
int r;
/* Moves the transaction jobs to the set of active jobs */
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
/* Assume merged */
assert(!j->transaction_prev);
assert(!j->transaction_next);
if (j->installed)
continue;
if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
goto rollback;
}
while ((j = hashmap_steal_first(m->transaction_jobs))) {
if (j->installed)
continue;
if (j->unit->meta.job)
job_free(j->unit->meta.job);
j->unit->meta.job = j;
j->installed = true;
/* We're fully installed. Now let's free data we don't
* need anymore. */
assert(!j->transaction_next);
assert(!j->transaction_prev);
job_add_to_run_queue(j);
job_add_to_dbus_queue(j);
}
/* As last step, kill all remaining job dependencies. */
transaction_clean_dependencies(m);
return 0;
rollback:
HASHMAP_FOREACH(j, m->transaction_jobs, i) {
if (j->installed)
continue;
hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
}
return r;
}
static int transaction_activate(Manager *m, JobMode mode) {
int r;
unsigned generation = 1;
assert(m);
/* This applies the changes recorded in transaction_jobs to
* the actual list of jobs, if possible. */
/* First step: figure out which jobs matter */
transaction_find_jobs_that_matter_to_anchor(m, NULL, 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. */
transaction_minimize_impact(m);
/* Third step: Drop redundant jobs */
transaction_drop_redundant(m);
for (;;) {
/* Fourth step: Let's remove unneeded jobs that might
* be lurking. */
transaction_collect_garbage(m);
/* Fifth step: verify order makes sense and correct
* cycles if necessary and possible */
if ((r = transaction_verify_order(m, &generation)) >= 0)
break;
if (r != -EAGAIN) {
log_debug("Requested transaction contains an unfixable cyclic ordering dependency: %s", strerror(-r));
goto rollback;
}
/* 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 */
if ((r = transaction_merge_jobs(m)) >= 0)
break;
if (r != -EAGAIN) {
log_debug("Requested transaction contains unmergable jobs: %s", strerror(-r));
goto rollback;
}
/* Seventh 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 ... */
}
/* Eights step: Drop redundant jobs again, if the merging now allows us to drop more. */
transaction_drop_redundant(m);
/* Ninth step: check whether we can actually apply this */
if (mode == JOB_FAIL)
if ((r = transaction_is_destructive(m, mode)) < 0) {
log_debug("Requested transaction contradicts existing jobs: %s", strerror(-r));
goto rollback;
}
/* Tenth step: apply changes */
if ((r = transaction_apply(m, mode)) < 0) {
log_debug("Failed to apply transaction: %s", strerror(-r));
goto rollback;
}
assert(hashmap_isempty(m->transaction_jobs));
assert(!m->transaction_anchor);
return 0;
rollback:
transaction_abort(m);
return r;
}
static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool override, bool *is_new) {
Job *j, *f;
int r;
assert(m);
assert(unit);
/* Looks for an axisting prospective job and returns that. If
* it doesn't exist it is created and added to the prospective
* jobs list. */
f = hashmap_get(m->transaction_jobs, unit);
LIST_FOREACH(transaction, j, f) {
assert(j->unit == unit);
if (j->type == type) {
if (is_new)
*is_new = false;
return j;
}
}
if (unit->meta.job && unit->meta.job->type == type)
j = unit->meta.job;
else if (!(j = job_new(m, type, unit)))
return NULL;
j->generation = 0;
j->marker = NULL;
j->matters_to_anchor = false;
j->override = override;
LIST_PREPEND(Job, transaction, f, j);
if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
job_free(j);
return NULL;
}
if (is_new)
*is_new = true;
log_debug("Added job %s/%s to transaction.", unit->meta.id, job_type_to_string(type));
return j;
}
void manager_transaction_unlink_job(Manager *m, Job *j, bool delete_dependencies) {
assert(m);
assert(j);
if (j->transaction_prev)
j->transaction_prev->transaction_next = j->transaction_next;
else if (j->transaction_next)
hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
else
hashmap_remove_value(m->transaction_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_debug("Deleting job %s/%s as dependency of job %s/%s",
other->unit->meta.id, job_type_to_string(other->type),
j->unit->meta.id, job_type_to_string(j->type));
transaction_delete_job(m, other, delete_dependencies);
}
}
}
static int transaction_add_job_and_dependencies(
Manager *m,
JobType type,
Unit *unit,
Job *by,
bool matters,
bool override,
Job **_ret) {
Job *ret;
Iterator i;
Unit *dep;
int r;
bool is_new;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(unit);
if (unit->meta.load_state != UNIT_LOADED)
return -EINVAL;
if (!unit_job_is_applicable(unit, type))
return -EBADR;
/* First add the job. */
if (!(ret = transaction_add_one_job(m, type, unit, override, &is_new)))
return -ENOMEM;
/* Then, add a link to the job. */
if (!job_dependency_new(by, ret, matters))
return -ENOMEM;
if (is_new) {
/* Finally, recursively add in all dependencies. */
if (type == JOB_START || type == JOB_RELOAD_OR_START) {
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
goto fail;
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES_OVERRIDABLE], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !override, override, NULL)) < 0 && r != -EBADR)
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, false, NULL)) < 0)
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
goto fail;
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE_OVERRIDABLE], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !override, override, NULL)) < 0 && r != -EBADR)
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
goto fail;
} else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
goto fail;
}
/* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
}
if (_ret)
*_ret = ret;
return 0;
fail:
return r;
}
int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool override, Job **_ret) {
int r;
Job *ret;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(unit);
assert(mode < _JOB_MODE_MAX);
log_debug("Trying to enqueue job %s/%s", unit->meta.id, job_type_to_string(type));
if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, override, &ret)) < 0) {
transaction_abort(m);
return r;
}
if ((r = transaction_activate(m, mode)) < 0)
return r;
log_debug("Enqueued job %s/%s as %u", unit->meta.id, job_type_to_string(type), (unsigned) ret->id);
if (_ret)
*_ret = ret;
return 0;
}
int manager_add_job_by_name(Manager *m, JobType type, const char *name, JobMode mode, bool override, Job **_ret) {
Unit *unit;
int r;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(name);
assert(mode < _JOB_MODE_MAX);
if ((r = manager_load_unit(m, name, NULL, &unit)) < 0)
return r;
return manager_add_job(m, type, unit, mode, override, _ret);
}
Job *manager_get_job(Manager *m, uint32_t id) {
assert(m);
return hashmap_get(m->jobs, UINT32_TO_PTR(id));
}
Unit *manager_get_unit(Manager *m, const char *name) {
assert(m);
assert(name);
return hashmap_get(m->units, name);
}
unsigned manager_dispatch_load_queue(Manager *m) {
Meta *meta;
unsigned n = 0;
assert(m);
/* Make sure we are not run recursively */
if (m->dispatching_load_queue)
return 0;
m->dispatching_load_queue = true;
/* Dispatches the load queue. Takes a unit from the queue and
* tries to load its data until the queue is empty */
while ((meta = m->load_queue)) {
assert(meta->in_load_queue);
unit_load(UNIT(meta));
n++;
}
m->dispatching_load_queue = false;
return n;
}
int manager_load_unit(Manager *m, const char *name, const char *path, Unit **_ret) {
Unit *ret;
int r;
assert(m);
assert(name || path);
/* This will load the service information files, but not actually
* start any services or anything. */
if (path && !is_path(path))
return -EINVAL;
if (!name)
name = file_name_from_path(path);
if (!unit_name_is_valid(name))
return -EINVAL;
if ((ret = manager_get_unit(m, name))) {
*_ret = ret;
return 0;
}
if (!(ret = unit_new(m)))
return -ENOMEM;
if (path)
if (!(ret->meta.fragment_path = strdup(path))) {
unit_free(ret);
return -ENOMEM;
}
if ((r = unit_add_name(ret, name)) < 0) {
unit_free(ret);
return r;
}
unit_add_to_load_queue(ret);
unit_add_to_dbus_queue(ret);
manager_dispatch_load_queue(m);
if (_ret)
*_ret = unit_follow_merge(ret);
return 0;
}
void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
Iterator i;
Job *j;
assert(s);
assert(f);
HASHMAP_FOREACH(j, s->jobs, i)
job_dump(j, f, prefix);
}
void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
Iterator i;
Unit *u;
const char *t;
assert(s);
assert(f);
HASHMAP_FOREACH_KEY(u, t, s->units, i)
if (u->meta.id == t)
unit_dump(u, f, prefix);
}
void manager_clear_jobs(Manager *m) {
Job *j;
assert(m);
transaction_abort(m);
while ((j = hashmap_first(m->jobs)))
job_free(j);
}
unsigned manager_dispatch_run_queue(Manager *m) {
Job *j;
unsigned n = 0;
if (m->dispatching_run_queue)
return 0;
m->dispatching_run_queue = true;
while ((j = m->run_queue)) {
assert(j->installed);
assert(j->in_run_queue);
job_run_and_invalidate(j);
n++;
}
m->dispatching_run_queue = false;
return n;
}
unsigned manager_dispatch_dbus_queue(Manager *m) {
Job *j;
Meta *meta;
unsigned n = 0;
assert(m);
if (m->dispatching_dbus_queue)
return 0;
m->dispatching_dbus_queue = true;
while ((meta = m->dbus_unit_queue)) {
assert(meta->in_dbus_queue);
bus_unit_send_change_signal(UNIT(meta));
n++;
}
while ((j = m->dbus_job_queue)) {
assert(j->in_dbus_queue);
bus_job_send_change_signal(j);
n++;
}
m->dispatching_dbus_queue = false;
return n;
}
static int manager_dispatch_sigchld(Manager *m) {
assert(m);
for (;;) {
siginfo_t si;
Unit *u;
zero(si);
/* First we call waitd() for a PID and do not reap the
* zombie. That way we can still access /proc/$PID for
* it while it is a zombie. */
if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG|WNOWAIT) < 0) {
if (errno == ECHILD)
break;
if (errno == EINTR)
continue;
return -errno;
}
if (si.si_pid <= 0)
break;
if (si.si_code == CLD_EXITED || si.si_code == CLD_KILLED || si.si_code == CLD_DUMPED) {
char *name = NULL;
get_process_name(si.si_pid, &name);
log_debug("Got SIGCHLD for process %llu (%s)", (unsigned long long) si.si_pid, strna(name));
free(name);
}
/* And now, we actually reap the zombie. */
if (waitid(P_PID, si.si_pid, &si, WEXITED) < 0) {
if (errno == EINTR)
continue;
return -errno;
}
if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
continue;
log_debug("Child %llu died (code=%s, status=%i/%s)",
(long long unsigned) si.si_pid,
sigchld_code_to_string(si.si_code),
si.si_status,
strna(si.si_code == CLD_EXITED ? exit_status_to_string(si.si_status) : strsignal(si.si_status)));
if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
continue;
log_debug("Child %llu belongs to %s", (long long unsigned) si.si_pid, u->meta.id);
UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
}
return 0;
}
static void manager_start_target(Manager *m, const char *name) {
int r;
if ((r = manager_add_job_by_name(m, JOB_START, name, JOB_REPLACE, true, NULL)) < 0)
log_error("Failed to enqueue %s job: %s", name, strerror(-r));
}
static int manager_process_signal_fd(Manager *m, bool *quit) {
ssize_t n;
struct signalfd_siginfo sfsi;
bool sigchld = false;
assert(m);
for (;;) {
if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
if (n >= 0)
return -EIO;
if (errno == EAGAIN)
break;
return -errno;
}
switch (sfsi.ssi_signo) {
case SIGCHLD:
sigchld = true;
break;
case SIGINT:
case SIGTERM:
if (m->running_as == MANAGER_INIT) {
manager_start_target(m, SPECIAL_CTRL_ALT_DEL_TARGET);
break;
}
*quit = true;
return 0;
case SIGWINCH:
if (m->running_as == MANAGER_INIT)
manager_start_target(m, SPECIAL_KBREQUEST_TARGET);
/* This is a nop on non-init */
break;
case SIGPWR:
if (m->running_as == MANAGER_INIT)
manager_start_target(m, SPECIAL_SIGPWR_TARGET);
/* This is a nop on non-init */
break;
case SIGUSR1:
manager_dump_units(m, stdout, "\t");
manager_dump_jobs(m, stdout, "\t");
break;
case SIGUSR2: {
Unit *u;
u = manager_get_unit(m, SPECIAL_DBUS_SERVICE);
if (!u || UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u))) {
log_info("Trying to reconnect to bus...");
bus_init_system(m);
bus_init_api(m);
}
if (!u || !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u))) {
log_info("Loading D-Bus service...");
manager_start_target(m, SPECIAL_DBUS_SERVICE);
}
break;
}
default:
log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
}
}
if (sigchld)
return manager_dispatch_sigchld(m);
return 0;
}
static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
int r;
Watch *w;
assert(m);
assert(ev);
assert(w = ev->data.ptr);
switch (w->type) {
case WATCH_SIGNAL:
/* An incoming signal? */
if (ev->events != EPOLLIN)
return -EINVAL;
if ((r = manager_process_signal_fd(m, quit)) < 0)
return r;
break;
case WATCH_FD:
/* Some fd event, to be dispatched to the units */
UNIT_VTABLE(w->data.unit)->fd_event(w->data.unit, w->fd, ev->events, w);
break;
case WATCH_TIMER: {
uint64_t v;
ssize_t k;
/* Some timer event, to be dispatched to the units */
if ((k = read(w->fd, &v, sizeof(v))) != sizeof(v)) {
if (k < 0 && (errno == EINTR || errno == EAGAIN))
break;
return k < 0 ? -errno : -EIO;
}
UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
break;
}
case WATCH_MOUNT:
/* Some mount table change, intended for the mount subsystem */
mount_fd_event(m, ev->events);
break;
case WATCH_UDEV:
/* Some notification from udev, intended for the device subsystem */
device_fd_event(m, ev->events);
break;
case WATCH_DBUS_WATCH:
bus_watch_event(m, w, ev->events);
break;
case WATCH_DBUS_TIMEOUT:
bus_timeout_event(m, w, ev->events);
break;
default:
assert_not_reached("Unknown epoll event type.");
}
return 0;
}
int manager_loop(Manager *m) {
int r;
bool quit = false;
RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
assert(m);
do {
struct epoll_event event;
int n;
if (!ratelimit_test(&rl)) {
/* Yay, something is going seriously wrong, pause a little */
log_warning("Looping too fast. Throttling execution a little.");
sleep(1);
}
if (manager_dispatch_cleanup_queue(m) > 0)
continue;
if (manager_dispatch_load_queue(m) > 0)
continue;
if (manager_dispatch_run_queue(m) > 0)
continue;
if (bus_dispatch(m) > 0)
continue;
if (manager_dispatch_dbus_queue(m) > 0)
continue;
if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
if (errno == -EINTR)
continue;
return -errno;
}
assert(n == 1);
if ((r = process_event(m, &event, &quit)) < 0)
return r;
} while (!quit);
return 0;
}
int manager_get_unit_from_dbus_path(Manager *m, const char *s, Unit **_u) {
char *n;
Unit *u;
assert(m);
assert(s);
assert(_u);
if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
return -EINVAL;
if (!(n = bus_path_unescape(s+31)))
return -ENOMEM;
u = manager_get_unit(m, n);
free(n);
if (!u)
return -ENOENT;
*_u = u;
return 0;
}
int manager_get_job_from_dbus_path(Manager *m, const char *s, Job **_j) {
Job *j;
unsigned id;
int r;
assert(m);
assert(s);
assert(_j);
if (!startswith(s, "/org/freedesktop/systemd1/job/"))
return -EINVAL;
if ((r = safe_atou(s + 30, &id)) < 0)
return r;
if (!(j = manager_get_job(m, id)))
return -ENOENT;
*_j = j;
return 0;
}
static bool manager_utmp_good(Manager *m) {
int r;
assert(m);
if ((r = mount_path_is_mounted(m, _PATH_UTMPX)) <= 0) {
if (r < 0)
log_warning("Failed to determine whether " _PATH_UTMPX " is mounted: %s", strerror(-r));
return false;
}
return true;
}
void manager_write_utmp_reboot(Manager *m) {
int r;
assert(m);
if (m->utmp_reboot_written)
return;
if (m->running_as != MANAGER_INIT)
return;
if (!manager_utmp_good(m))
return;
if ((r = utmp_put_reboot(m->boot_timestamp)) < 0) {
if (r != -ENOENT && r != -EROFS)
log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
return;
}
m->utmp_reboot_written = true;
}
void manager_write_utmp_runlevel(Manager *m, Unit *u) {
int runlevel, r;
assert(m);
assert(u);
if (u->meta.type != UNIT_TARGET)
return;
if (m->running_as != MANAGER_INIT)
return;
if (!manager_utmp_good(m))
return;
if ((runlevel = target_get_runlevel(TARGET(u))) <= 0)
return;
if ((r = utmp_put_runlevel(0, runlevel, 0)) < 0) {
if (r != -ENOENT && r != -EROFS)
log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
}
}
void manager_dispatch_bus_name_owner_changed(
Manager *m,
const char *name,
const char* old_owner,
const char *new_owner) {
Unit *u;
assert(m);
assert(name);
if (!(u = hashmap_get(m->watch_bus, name)))
return;
UNIT_VTABLE(u)->bus_name_owner_change(u, name, old_owner, new_owner);
}
void manager_dispatch_bus_query_pid_done(
Manager *m,
const char *name,
pid_t pid) {
Unit *u;
assert(m);
assert(name);
assert(pid >= 1);
if (!(u = hashmap_get(m->watch_bus, name)))
return;
UNIT_VTABLE(u)->bus_query_pid_done(u, name, pid);
}
static const char* const manager_running_as_table[_MANAGER_RUNNING_AS_MAX] = {
[MANAGER_INIT] = "init",
[MANAGER_SYSTEM] = "system",
[MANAGER_SESSION] = "session"
};
DEFINE_STRING_TABLE_LOOKUP(manager_running_as, ManagerRunningAs);
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