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69dd2852bb2c433b517d89792adb4461a4178aa1
systemd/src/manager.c
Lennart Poettering 69dd2852bb manager: when two pending jobs conflict, keep the one that "conflicts", remove the one that is "conflicted" 
This gives the writer of units control which unit is kept and which is
stopped when two units conflict.
2010-08-09 22:32:30 +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 <termios.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.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"
#include "dbus-unit.h"
#include "dbus-job.h"
#include "missing.h"
#include "path-lookup.h"
#include "special.h"
#include "bus-errors.h"
/* As soon as 16 units are in our GC queue, make sure to run a gc sweep */
#define GC_QUEUE_ENTRIES_MAX 16
/* As soon as 5s passed since a unit was added to our GC queue, make sure to run a gc sweep */
#define GC_QUEUE_USEC_MAX (10*USEC_PER_SEC)
/* Where clients shall send notification messages to */
#define NOTIFY_SOCKET "/org/freedesktop/systemd1/notify"
static int manager_setup_notify(Manager *m) {
union {
struct sockaddr sa;
struct sockaddr_un un;
} sa;
struct epoll_event ev;
int one = 1;
assert(m);
m->notify_watch.type = WATCH_NOTIFY;
if ((m->notify_watch.fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0)) < 0) {
log_error("Failed to allocate notification socket: %m");
return -errno;
}
zero(sa);
sa.sa.sa_family = AF_UNIX;
if (getpid() != 1)
snprintf(sa.un.sun_path+1, sizeof(sa.un.sun_path)-1, NOTIFY_SOCKET "/%llu", random_ull());
else
strncpy(sa.un.sun_path+1, NOTIFY_SOCKET, sizeof(sa.un.sun_path)-1);
if (bind(m->notify_watch.fd, &sa.sa, sizeof(sa_family_t) + 1 + strlen(sa.un.sun_path+1)) < 0) {
log_error("bind() failed: %m");
return -errno;
}
if (setsockopt(m->notify_watch.fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) {
log_error("SO_PASSCRED failed: %m");
return -errno;
}
zero(ev);
ev.events = EPOLLIN;
ev.data.ptr = &m->notify_watch;
if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->notify_watch.fd, &ev) < 0)
return -errno;
if (!(m->notify_socket = strdup(sa.un.sun_path+1)))
return -ENOMEM;
return 0;
}
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|O_NOCTTY)) < 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);
sigset_add_many(&mask,
SIGCHLD, /* Child died */
SIGTERM, /* Reexecute daemon */
SIGHUP, /* Reload configuration */
SIGUSR1, /* systemd/upstart: reconnect to D-Bus */
SIGUSR2, /* systemd: dump status */
SIGINT, /* Kernel sends us this on control-alt-del */
SIGWINCH, /* Kernel sends us this on kbrequest (alt-arrowup) */
SIGPWR, /* Some kernel drivers and upsd send us this on power failure */
SIGRTMIN+0, /* systemd: start default.target */
SIGRTMIN+1, /* systemd: start rescue.target */
SIGRTMIN+2, /* systemd: isolate emergency.target */
SIGRTMIN+3, /* systemd: start halt.target */
SIGRTMIN+4, /* systemd: start poweroff.target */
SIGRTMIN+5, /* systemd: start reboot.target */
-1);
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_SYSTEM)
return enable_special_signals(m);
return 0;
}
int manager_new(ManagerRunningAs running_as, 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;
dual_timestamp_get(&m->startup_timestamp);
m->running_as = running_as;
m->name_data_slot = m->subscribed_data_slot = -1;
m->exit_code = _MANAGER_EXIT_CODE_INVALID;
m->pin_cgroupfs_fd = -1;
m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = m->dev_autofs_fd = -1;
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
if (!(m->environment = strv_copy(environ)))
goto fail;
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 = lookup_paths_init(&m->lookup_paths, m->running_as)) < 0)
goto fail;
if ((r = manager_setup_signals(m)) < 0)
goto fail;
if ((r = manager_setup_cgroup(m)) < 0)
goto fail;
if ((r = manager_setup_notify(m)) < 0)
goto fail;
/* Try to connect to the busses, if possible. */
if ((r = bus_init(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;
}
enum {
GC_OFFSET_IN_PATH, /* This one is on the path we were travelling */
GC_OFFSET_UNSURE, /* No clue */
GC_OFFSET_GOOD, /* We still need this unit */
GC_OFFSET_BAD, /* We don't need this unit anymore */
_GC_OFFSET_MAX
};
static void unit_gc_sweep(Unit *u, unsigned gc_marker) {
Iterator i;
Unit *other;
bool is_bad;
assert(u);
if (u->meta.gc_marker == gc_marker + GC_OFFSET_GOOD ||
u->meta.gc_marker == gc_marker + GC_OFFSET_BAD ||
u->meta.gc_marker == gc_marker + GC_OFFSET_IN_PATH)
return;
if (u->meta.in_cleanup_queue)
goto bad;
if (unit_check_gc(u))
goto good;
u->meta.gc_marker = gc_marker + GC_OFFSET_IN_PATH;
is_bad = true;
SET_FOREACH(other, u->meta.dependencies[UNIT_REFERENCED_BY], i) {
unit_gc_sweep(other, gc_marker);
if (other->meta.gc_marker == gc_marker + GC_OFFSET_GOOD)
goto good;
if (other->meta.gc_marker != gc_marker + GC_OFFSET_BAD)
is_bad = false;
}
if (is_bad)
goto bad;
/* We were unable to find anything out about this entry, so
* let's investigate it later */
u->meta.gc_marker = gc_marker + GC_OFFSET_UNSURE;
unit_add_to_gc_queue(u);
return;
bad:
/* We definitely know that this one is not useful anymore, so
* let's mark it for deletion */
u->meta.gc_marker = gc_marker + GC_OFFSET_BAD;
unit_add_to_cleanup_queue(u);
return;
good:
u->meta.gc_marker = gc_marker + GC_OFFSET_GOOD;
}
static unsigned manager_dispatch_gc_queue(Manager *m) {
Meta *meta;
unsigned n = 0;
unsigned gc_marker;
assert(m);
if ((m->n_in_gc_queue < GC_QUEUE_ENTRIES_MAX) &&
(m->gc_queue_timestamp <= 0 ||
(m->gc_queue_timestamp + GC_QUEUE_USEC_MAX) > now(CLOCK_MONOTONIC)))
return 0;
log_debug("Running GC...");
m->gc_marker += _GC_OFFSET_MAX;
if (m->gc_marker + _GC_OFFSET_MAX <= _GC_OFFSET_MAX)
m->gc_marker = 1;
gc_marker = m->gc_marker;
while ((meta = m->gc_queue)) {
assert(meta->in_gc_queue);
unit_gc_sweep((Unit*) meta, gc_marker);
LIST_REMOVE(Meta, gc_queue, m->gc_queue, meta);
meta->in_gc_queue = false;
n++;
if (meta->gc_marker == gc_marker + GC_OFFSET_BAD ||
meta->gc_marker == gc_marker + GC_OFFSET_UNSURE) {
log_debug("Collecting %s", meta->id);
meta->gc_marker = gc_marker + GC_OFFSET_BAD;
unit_add_to_cleanup_queue((Unit*) meta);
}
}
m->n_in_gc_queue = 0;
m->gc_queue_timestamp = 0;
return n;
}
static void manager_clear_jobs_and_units(Manager *m) {
Job *j;
Unit *u;
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);
assert(!m->load_queue);
assert(!m->run_queue);
assert(!m->dbus_unit_queue);
assert(!m->dbus_job_queue);
assert(!m->cleanup_queue);
assert(!m->gc_queue);
assert(hashmap_isempty(m->transaction_jobs));
assert(hashmap_isempty(m->jobs));
assert(hashmap_isempty(m->units));
}
void manager_free(Manager *m) {
UnitType c;
assert(m);
manager_clear_jobs_and_units(m);
for (c = 0; c < _UNIT_TYPE_MAX; c++)
if (unit_vtable[c]->shutdown)
unit_vtable[c]->shutdown(m);
/* If we reexecute ourselves, we keep the root cgroup
* around */
manager_shutdown_cgroup(m, m->exit_code != MANAGER_REEXECUTE);
bus_done(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_nofail(m->epoll_fd);
if (m->signal_watch.fd >= 0)
close_nointr_nofail(m->signal_watch.fd);
if (m->notify_watch.fd >= 0)
close_nointr_nofail(m->notify_watch.fd);
free(m->notify_socket);
lookup_paths_free(&m->lookup_paths);
strv_free(m->environment);
hashmap_free(m->cgroup_bondings);
set_free_free(m->unit_path_cache);
free(m);
}
int manager_enumerate(Manager *m) {
int r = 0, q;
UnitType c;
assert(m);
/* 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 ((q = unit_vtable[c]->enumerate(m)) < 0)
r = q;
manager_dispatch_load_queue(m);
return r;
}
int manager_coldplug(Manager *m) {
int r = 0, q;
Iterator i;
Unit *u;
char *k;
assert(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 ((q = unit_coldplug(u)) < 0)
r = q;
}
return r;
}
static void manager_build_unit_path_cache(Manager *m) {
char **i;
DIR *d = NULL;
int r;
assert(m);
set_free_free(m->unit_path_cache);
if (!(m->unit_path_cache = set_new(string_hash_func, string_compare_func))) {
log_error("Failed to allocate unit path cache.");
return;
}
/* This simply builds a list of files we know exist, so that
* we don't always have to go to disk */
STRV_FOREACH(i, m->lookup_paths.unit_path) {
struct dirent *de;
if (!(d = opendir(*i))) {
log_error("Failed to open directory: %m");
continue;
}
while ((de = readdir(d))) {
char *p;
if (ignore_file(de->d_name))
continue;
if (asprintf(&p, "%s/%s", streq(*i, "/") ? "" : *i, de->d_name) < 0) {
r = -ENOMEM;
goto fail;
}
if ((r = set_put(m->unit_path_cache, p)) < 0) {
free(p);
goto fail;
}
}
closedir(d);
d = NULL;
}
return;
fail:
log_error("Failed to build unit path cache: %s", strerror(-r));
set_free_free(m->unit_path_cache);
m->unit_path_cache = NULL;
if (d)
closedir(d);
}
int manager_startup(Manager *m, FILE *serialization, FDSet *fds) {
int r, q;
assert(m);
manager_build_unit_path_cache(m);
/* If we will deserialize make sure that during enumeration
* this is already known, so we increase the counter here
* already */
if (serialization)
m->n_deserializing ++;
/* First, enumerate what we can from all config files */
r = manager_enumerate(m);
/* Second, deserialize if there is something to deserialize */
if (serialization)
if ((q = manager_deserialize(m, serialization, fds)) < 0)
r = q;
/* Third, fire things up! */
if ((q = manager_coldplug(m)) < 0)
r = q;
if (serialization) {
assert(m->n_deserializing > 0);
m->n_deserializing --;
}
/* Now that the initial devices are available, let's see if we
* can write the utmp file */
manager_write_utmp_reboot(m);
return r;
}
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 bool job_is_conflicted_by(Job *j) {
JobDependency *l;
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(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 && !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_debug("Looking at job %s/%s conflicted_by=%s", j->unit->meta.id, job_type_to_string(j->type), yes_no(j->type == JOB_STOP && job_is_conflicted_by(j)));
log_debug("Looking at job %s/%s conflicted_by=%s", k->unit->meta.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 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("Fixing conflicting jobs 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, DBusError *e) {
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 */
dbus_set_error(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->meta.id);
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, DBusError *e) {
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. */
/* Have we seen this before? */
if (j->generation == generation) {
Job *k, *delete;
/* 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. */
log_warning("Found ordering cycle on %s/%s", j->unit->meta.id, job_type_to_string(j->type));
delete = NULL;
for (k = from; k; k = ((k->generation == generation && k->marker != k) ? k->marker : NULL)) {
log_info("Walked on cycle path to %s/%s", k->unit->meta.id, job_type_to_string(k->type));
if (!delete &&
!k->installed &&
!unit_matters_to_anchor(k->unit, 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;
}
if (delete) {
log_warning("Breaking ordering cycle by deleting job %s/%s", k->unit->meta.id, job_type_to_string(k->type));
transaction_delete_unit(m, delete->unit);
return -EAGAIN;
}
log_error("Unable to break cycle");
dbus_set_error(e, BUS_ERROR_TRANSACTION_ORDER_IS_CYCLIC, "Transaction order is cyclic. See logs for details.");
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. We use
* a special marker for the beginning: we point to
* ourselves. */
j->marker = from ? from : j;
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, e)) < 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, DBusError *e) {
Job *j;
int r;
Iterator i;
unsigned g;
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. */
g = (*generation)++;
HASHMAP_FOREACH(j, m->transaction_jobs, i)
if ((r = transaction_verify_order_one(m, j, NULL, g, e)) < 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, DBusError *e) {
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)) {
dbus_set_error(e, BUS_ERROR_TRANSACTION_IS_DESTRUCTIVE, "Transaction is destructive.");
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->type);
if (!stops_running_service && !changes_existing_job)
continue;
if (stops_running_service)
log_info("%s/%s would stop a running service.", j->unit->meta.id, job_type_to_string(j->type));
if (changes_existing_job)
log_info("%s/%s would change existing job.", j->unit->meta.id, job_type_to_string(j->type));
/* Ok, let's get rid of this */
log_info("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) {
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);
job_start_timer(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, DBusError *e) {
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, e)) >= 0)
break;
if (r != -EAGAIN) {
log_warning("Requested transaction contains an unfixable cyclic ordering dependency: %s", bus_error(e, 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, e)) >= 0)
break;
if (r != -EAGAIN) {
log_warning("Requested transaction contains unmergable jobs: %s", bus_error(e, 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, e)) < 0) {
log_notice("Requested transaction contradicts existing jobs: %s", bus_error(e, r));
goto rollback;
}
/* Tenth step: apply changes */
if ((r = transaction_apply(m)) < 0) {
log_warning("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,
bool conflicts,
DBusError *e,
Job **_ret) {
Job *ret;
Iterator i;
Unit *dep;
int r;
bool is_new;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(unit);
if (type != JOB_STOP &&
unit->meta.load_state != UNIT_LOADED) {
dbus_set_error(e, BUS_ERROR_LOAD_FAILED, "Unit %s failed to load. See logs for details.", unit->meta.id);
return -EINVAL;
}
if (!unit_job_is_applicable(unit, type)) {
dbus_set_error(e, BUS_ERROR_JOB_TYPE_NOT_APPLICABLE, "Job type %s is not applicable for unit %s.", job_type_to_string(type), unit->meta.id);
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, conflicts))
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, false, e, 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, false, e, NULL)) < 0 && r != -EBADR) {
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, bus_error(e, r));
dbus_error_free(e);
}
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, false, false, e, NULL)) < 0) {
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, bus_error(e, r));
dbus_error_free(e);
}
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, false, e, 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, false, e, NULL)) < 0 && r != -EBADR) {
log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, bus_error(e, r));
dbus_error_free(e);
}
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, override, true, e, NULL)) < 0 && r != -EBADR)
goto fail;
SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTED_BY], i)
if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, override, false, e, 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, false, e, NULL)) < 0 && r != -EBADR)
goto fail;
}
/* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
}
if (_ret)
*_ret = ret;
return 0;
fail:
return r;
}
static int transaction_add_isolate_jobs(Manager *m) {
Iterator i;
Unit *u;
char *k;
int r;
assert(m);
HASHMAP_FOREACH_KEY(u, k, m->units, i) {
/* ignore aliases */
if (u->meta.id != k)
continue;
if (UNIT_VTABLE(u)->no_isolate)
continue;
/* No need to stop inactive jobs */
if (UNIT_IS_INACTIVE_OR_MAINTENANCE(unit_active_state(u)))
continue;
/* Is there already something listed for this? */
if (hashmap_get(m->transaction_jobs, u))
continue;
if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, u, NULL, true, false, false, NULL, NULL)) < 0)
log_warning("Cannot add isolate job for unit %s, ignoring: %s", u->meta.id, strerror(-r));
}
return 0;
}
int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool override, DBusError *e, Job **_ret) {
int r;
Job *ret;
assert(m);
assert(type < _JOB_TYPE_MAX);
assert(unit);
assert(mode < _JOB_MODE_MAX);
if (mode == JOB_ISOLATE && type != JOB_START) {
dbus_set_error(e, BUS_ERROR_INVALID_JOB_MODE, "Isolate is only valid for start.");
return -EINVAL;
}
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, false, e, &ret)) < 0) {
transaction_abort(m);
return r;
}
if (mode == JOB_ISOLATE)
if ((r = transaction_add_isolate_jobs(m)) < 0) {
transaction_abort(m);
return r;
}
if ((r = transaction_activate(m, mode, e)) < 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, DBusError *e, 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, NULL, &unit)) < 0)
return r;
return manager_add_job(m, type, unit, mode, override, e, _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_prepare(Manager *m, const char *name, const char *path, DBusError *e, Unit **_ret) {
Unit *ret;
int r;
assert(m);
assert(name || path);
/* This will prepare the unit for loading, but not actually
* load anything from disk. */
if (path && !is_path(path)) {
dbus_set_error(e, BUS_ERROR_INVALID_PATH, "Path %s is not absolute.", path);
return -EINVAL;
}
if (!name)
name = file_name_from_path(path);
if (!unit_name_is_valid(name)) {
dbus_set_error(e, BUS_ERROR_INVALID_NAME, "Unit name %s is not valid.", name);
return -EINVAL;
}
if ((ret = manager_get_unit(m, name))) {
*_ret = ret;
return 1;
}
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);
unit_add_to_gc_queue(ret);
if (_ret)
*_ret = ret;
return 0;
}
int manager_load_unit(Manager *m, const char *name, const char *path, DBusError *e, Unit **_ret) {
int r;
assert(m);
/* This will load the service information files, but not actually
* start any services or anything. */
if ((r = manager_load_unit_prepare(m, name, path, e, _ret)) != 0)
return r;
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_process_notify_fd(Manager *m) {
ssize_t n;
assert(m);
for (;;) {
char buf[4096];
struct msghdr msghdr;
struct iovec iovec;
struct ucred *ucred;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
} control;
Unit *u;
char **tags;
zero(iovec);
iovec.iov_base = buf;
iovec.iov_len = sizeof(buf)-1;
zero(control);
zero(msghdr);
msghdr.msg_iov = &iovec;
msghdr.msg_iovlen = 1;
msghdr.msg_control = &control;
msghdr.msg_controllen = sizeof(control);
if ((n = recvmsg(m->notify_watch.fd, &msghdr, MSG_DONTWAIT)) <= 0) {
if (n >= 0)
return -EIO;
if (errno == EAGAIN)
break;
return -errno;
}
if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) ||
control.cmsghdr.cmsg_level != SOL_SOCKET ||
control.cmsghdr.cmsg_type != SCM_CREDENTIALS ||
control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
log_warning("Received notify message without credentials. Ignoring.");
continue;
}
ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
if (!(u = hashmap_get(m->watch_pids, LONG_TO_PTR(ucred->pid))))
if (!(u = cgroup_unit_by_pid(m, ucred->pid))) {
log_warning("Cannot find unit for notify message of PID %lu.", (unsigned long) ucred->pid);
continue;
}
assert((size_t) n < sizeof(buf));
buf[n] = 0;
if (!(tags = strv_split(buf, "\n\r")))
return -ENOMEM;
log_debug("Got notification message for unit %s", u->meta.id);
if (UNIT_VTABLE(u)->notify_message)
UNIT_VTABLE(u)->notify_message(u, ucred->pid, tags);
strv_free(tags);
}
return 0;
}
static int manager_dispatch_sigchld(Manager *m) {
assert(m);
for (;;) {
siginfo_t si;
Unit *u;
int r;
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 %lu (%s)", (unsigned long) si.si_pid, strna(name));
free(name);
}
/* Let's flush any message the dying child might still
* have queued for us. This ensures that the process
* still exists in /proc so that we can figure out
* which cgroup and hence unit it belongs to. */
if ((r = manager_process_notify_fd(m)) < 0)
return r;
/* And now figure out the unit this belongs to */
if (!(u = hashmap_get(m->watch_pids, LONG_TO_PTR(si.si_pid))))
u = cgroup_unit_by_pid(m, si.si_pid);
/* 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 %lu died (code=%s, status=%i/%s)",
(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) : signal_to_string(si.si_status)));
if (!u)
continue;
log_debug("Child %lu belongs to %s", (long unsigned) si.si_pid, u->meta.id);
hashmap_remove(m->watch_pids, LONG_TO_PTR(si.si_pid));
UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
}
return 0;
}
static int manager_start_target(Manager *m, const char *name, JobMode mode) {
int r;
DBusError error;
dbus_error_init(&error);
log_info("Activating special unit %s", name);
if ((r = manager_add_job_by_name(m, JOB_START, name, mode, true, &error, NULL)) < 0)
log_error("Failed to enqueue %s job: %s", name, bus_error(&error, r));
dbus_error_free(&error);
return r;
}
static int manager_process_signal_fd(Manager *m) {
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;
}
log_debug("Received SIG%s", strna(signal_to_string(sfsi.ssi_signo)));
switch (sfsi.ssi_signo) {
case SIGCHLD:
sigchld = true;
break;
case SIGTERM:
if (m->running_as == MANAGER_SYSTEM) {
/* This is for compatibility with the
* original sysvinit */
m->exit_code = MANAGER_REEXECUTE;
break;
}
/* Fall through */
case SIGINT:
if (m->running_as == MANAGER_SYSTEM) {
manager_start_target(m, SPECIAL_CTRL_ALT_DEL_TARGET, JOB_REPLACE);
break;
}
/* Run the exit target if there is one, if not, just exit. */
if (manager_start_target(m, SPECIAL_EXIT_SERVICE, JOB_REPLACE) < 0) {
m->exit_code = MANAGER_EXIT;
return 0;
}
break;
case SIGWINCH:
if (m->running_as == MANAGER_SYSTEM)
manager_start_target(m, SPECIAL_KBREQUEST_TARGET, JOB_REPLACE);
/* This is a nop on non-init */
break;
case SIGPWR:
if (m->running_as == MANAGER_SYSTEM)
manager_start_target(m, SPECIAL_SIGPWR_TARGET, JOB_REPLACE);
/* This is a nop on non-init */
break;
case SIGUSR1: {
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(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, JOB_REPLACE);
}
break;
}
case SIGUSR2: {
FILE *f;
char *dump = NULL;
size_t size;
if (!(f = open_memstream(&dump, &size))) {
log_warning("Failed to allocate memory stream.");
break;
}
manager_dump_units(m, f, "\t");
manager_dump_jobs(m, f, "\t");
if (ferror(f)) {
fclose(f);
free(dump);
log_warning("Failed to write status stream");
break;
}
fclose(f);
log_dump(LOG_INFO, dump);
free(dump);
break;
}
case SIGHUP:
m->exit_code = MANAGER_RELOAD;
break;
default: {
static const char * const table[] = {
[0] = SPECIAL_DEFAULT_TARGET,
[1] = SPECIAL_RESCUE_TARGET,
[2] = SPECIAL_EMERGENCY_TARGET,
[3] = SPECIAL_HALT_TARGET,
[4] = SPECIAL_POWEROFF_TARGET,
[5] = SPECIAL_REBOOT_TARGET
};
if ((int) sfsi.ssi_signo >= SIGRTMIN+0 &&
(int) sfsi.ssi_signo < SIGRTMIN+(int) ELEMENTSOF(table)) {
manager_start_target(m, table[sfsi.ssi_signo - SIGRTMIN],
(sfsi.ssi_signo == 1 || sfsi.ssi_signo == 2) ? JOB_ISOLATE : JOB_REPLACE);
break;
}
log_warning("Got unhandled signal <%s>.", strna(signal_to_string(sfsi.ssi_signo)));
}
}
}
if (sigchld)
return manager_dispatch_sigchld(m);
return 0;
}
static int process_event(Manager *m, struct epoll_event *ev) {
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)) < 0)
return r;
break;
case WATCH_NOTIFY:
/* An incoming daemon notification event? */
if (ev->events != EPOLLIN)
return -EINVAL;
if ((r = manager_process_notify_fd(m)) < 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_UNIT_TIMER:
case WATCH_JOB_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;
}
if (w->type == WATCH_UNIT_TIMER)
UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
else
job_timer_event(w->data.job, 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;
RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
assert(m);
m->exit_code = MANAGER_RUNNING;
/* Release the path cache */
set_free_free(m->unit_path_cache);
m->unit_path_cache = NULL;
/* There might still be some zombies hanging around from
* before we were exec()'ed. Leat's reap them */
if ((r = manager_dispatch_sigchld(m)) < 0)
return r;
while (m->exit_code == MANAGER_RUNNING) {
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_load_queue(m) > 0)
continue;
if (manager_dispatch_run_queue(m) > 0)
continue;
if (bus_dispatch(m) > 0)
continue;
if (manager_dispatch_cleanup_queue(m) > 0)
continue;
if (manager_dispatch_gc_queue(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)) < 0)
return r;
}
return m->exit_code;
}
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_SYSTEM)
return;
if (!manager_utmp_good(m))
return;
if ((r = utmp_put_reboot(m->startup_timestamp.realtime)) < 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_SYSTEM)
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);
}
int manager_open_serialization(Manager *m, FILE **_f) {
char *path;
mode_t saved_umask;
int fd;
FILE *f;
assert(_f);
if (m->running_as == MANAGER_SYSTEM) {
mkdir_p("/dev/.systemd", 0755);
if (asprintf(&path, "/dev/.systemd/dump-%lu-XXXXXX", (unsigned long) getpid()) < 0)
return -ENOMEM;
} else {
if (asprintf(&path, "/tmp/systemd-dump-%lu-XXXXXX", (unsigned long) getpid()) < 0)
return -ENOMEM;
}
saved_umask = umask(0077);
fd = mkostemp(path, O_RDWR|O_CLOEXEC);
umask(saved_umask);
if (fd < 0) {
free(path);
return -errno;
}
unlink(path);
log_debug("Serializing state to %s", path);
free(path);
if (!(f = fdopen(fd, "w+")) < 0)
return -errno;
*_f = f;
return 0;
}
int manager_serialize(Manager *m, FILE *f, FDSet *fds) {
Iterator i;
Unit *u;
const char *t;
int r;
assert(m);
assert(f);
assert(fds);
HASHMAP_FOREACH_KEY(u, t, m->units, i) {
if (u->meta.id != t)
continue;
if (!unit_can_serialize(u))
continue;
/* Start marker */
fputs(u->meta.id, f);
fputc('\n', f);
if ((r = unit_serialize(u, f, fds)) < 0)
return r;
}
if (ferror(f))
return -EIO;
return 0;
}
int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
int r = 0;
assert(m);
assert(f);
log_debug("Deserializing state...");
m->n_deserializing ++;
for (;;) {
Unit *u;
char name[UNIT_NAME_MAX+2];
/* Start marker */
if (!fgets(name, sizeof(name), f)) {
if (feof(f))
break;
r = -errno;
goto finish;
}
char_array_0(name);
if ((r = manager_load_unit(m, strstrip(name), NULL, NULL, &u)) < 0)
goto finish;
if ((r = unit_deserialize(u, f, fds)) < 0)
goto finish;
}
if (ferror(f)) {
r = -EIO;
goto finish;
}
r = 0;
finish:
assert(m->n_deserializing > 0);
m->n_deserializing --;
return r;
}
int manager_reload(Manager *m) {
int r, q;
FILE *f;
FDSet *fds;
assert(m);
if ((r = manager_open_serialization(m, &f)) < 0)
return r;
if (!(fds = fdset_new())) {
r = -ENOMEM;
goto finish;
}
if ((r = manager_serialize(m, f, fds)) < 0)
goto finish;
if (fseeko(f, 0, SEEK_SET) < 0) {
r = -errno;
goto finish;
}
/* From here on there is no way back. */
manager_clear_jobs_and_units(m);
/* Find new unit paths */
lookup_paths_free(&m->lookup_paths);
if ((q = lookup_paths_init(&m->lookup_paths, m->running_as)) < 0)
r = q;
m->n_deserializing ++;
/* First, enumerate what we can from all config files */
if ((q = manager_enumerate(m)) < 0)
r = q;
/* Second, deserialize our stored data */
if ((q = manager_deserialize(m, f, fds)) < 0)
r = q;
fclose(f);
f = NULL;
/* Third, fire things up! */
if ((q = manager_coldplug(m)) < 0)
r = q;
assert(m->n_deserializing > 0);
m->n_deserializing ++;
finish:
if (f)
fclose(f);
if (fds)
fdset_free(fds);
return r;
}
bool manager_is_booting_or_shutting_down(Manager *m) {
Unit *u;
assert(m);
/* Is the initial job still around? */
if (manager_get_job(m, 1))
return true;
/* Is there a job for the shutdown target? */
if (((u = manager_get_unit(m, SPECIAL_SHUTDOWN_TARGET))))
return !!u->meta.job;
return false;
}
void manager_reset_maintenance(Manager *m) {
Unit *u;
Iterator i;
assert(m);
HASHMAP_FOREACH(u, m->units, i)
unit_reset_maintenance(u);
}
static const char* const manager_running_as_table[_MANAGER_RUNNING_AS_MAX] = {
[MANAGER_SYSTEM] = "system",
[MANAGER_SESSION] = "session"
};
DEFINE_STRING_TABLE_LOOKUP(manager_running_as, ManagerRunningAs);
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