#include "sig-monitor.h"
#include "verbose.h"
-#if defined(REMOVE_SYSTEMD_EVENT)
-#include "fdev-epoll.h"
-#endif
-
#define EVENT_TIMEOUT_TOP ((uint64_t)-1)
#define EVENT_TIMEOUT_CHILD ((uint64_t)10000)
unsigned state; /**< encoded state */
int efd; /**< event notification */
struct sd_event *sdev; /**< the systemd event loop */
- pthread_cond_t cond; /**< condition */
struct fdev *fdev; /**< handling of events */
struct thread *holder; /**< holder of the evloop */
};
#define EVLOOP_STATE_WAIT 1U
#define EVLOOP_STATE_RUN 2U
-#define EVLOOP_STATE_LOCK 4U
/** Description of threads */
struct thread
{
struct thread *next; /**< next thread of the list */
struct thread *upper; /**< upper same thread */
+ struct thread *nholder;/**< next holder for evloop */
+ pthread_cond_t *cwhold;/**< condition wait for holding */
struct job *job; /**< currently processed job */
pthread_t tid; /**< the thread id */
volatile unsigned stop: 1; /**< stop requested */
};
/**
- * Description of synchonous callback
+ * Description of synchronous callback
*/
struct sync
{
/* list of threads */
static struct thread *threads;
static _Thread_local struct thread *current_thread;
-static _Thread_local struct evloop *current_evloop;
/* queue of pending jobs */
static struct job *first_job;
static struct job *free_jobs;
/* event loop */
-static struct evloop evloop[1];
-
-#if defined(REMOVE_SYSTEMD_EVENT)
-static struct fdev_epoll *fdevepoll;
-static int waitevt;
-#endif
+static struct evloop evloop;
/**
* Create a new job with the given parameters
job = malloc(sizeof *job);
pthread_mutex_lock(&mutex);
if (!job) {
+ ERROR("out of memory");
errno = ENOMEM;
goto end;
}
/* queue the jobs */
*pjob = job;
+ remains--;
}
/**
struct job *job = first_job;
while (job && job->blocked)
job = job->next;
+ if (job)
+ remains++;
return job;
}
job->callback(SIGABRT, job->arg);
}
-#if defined(REMOVE_SYSTEMD_EVENT)
-/**
- * Gets a fdev_epoll item.
- * @return a fdev_epoll or NULL in case of error
- */
-static struct fdev_epoll *get_fdevepoll()
-{
- struct fdev_epoll *result;
-
- result = fdevepoll;
- if (!result)
- result = fdevepoll = fdev_epoll_create();
-
- return result;
-}
-#endif
-
/**
* Monitored normal callback for events.
* This function is called by the monitor
{
int rc;
struct sd_event *se;
- struct evloop *el = arg;
if (!signum) {
- current_evloop = el;
- __atomic_store_n(&el->state, EVLOOP_STATE_LOCK|EVLOOP_STATE_RUN|EVLOOP_STATE_WAIT, __ATOMIC_RELAXED);
- __atomic_store_n(&el->holder, current_thread, __ATOMIC_RELAXED);
- se = el->sdev;
+ se = evloop.sdev;
rc = sd_event_prepare(se);
if (rc < 0) {
errno = -rc;
ERROR("sd_event_wait returned an error (state: %d): %m", sd_event_get_state(se));
}
}
- __atomic_and_fetch(&el->state, ~(EVLOOP_STATE_WAIT), __ATOMIC_RELAXED);
-
+ evloop.state = EVLOOP_STATE_RUN;
if (rc > 0) {
rc = sd_event_dispatch(se);
if (rc < 0) {
}
}
}
- __atomic_and_fetch(&el->state, ~(EVLOOP_STATE_WAIT|EVLOOP_STATE_RUN), __ATOMIC_RELAXED);
}
+/**
+ * Internal callback for evloop management.
+ * The effect of this function is hidden: it exits
+ * the waiting poll if any.
+ */
+static void evloop_on_efd_event()
+{
+ uint64_t x;
+ read(evloop.efd, &x, sizeof x);
+}
-#if defined(REMOVE_SYSTEMD_EVENT)
/**
- * Monitored normal loop for waiting events.
- * @param signum 0 on normal flow or the number
- * of the signal that interrupted the normal
- * flow
- * @param arg the events to run
+ * wakeup the event loop if needed by sending
+ * an event.
*/
-static void monitored_wait_and_dispatch(int signum, void *arg)
+static void evloop_wakeup()
{
- struct fdev_epoll *fdev_epoll = arg;
- if (!signum) {
- fdev_epoll_wait_and_dispatch(fdev_epoll, -1);
+ uint64_t x;
+
+ if (evloop.state & EVLOOP_STATE_WAIT) {
+ x = 1;
+ write(evloop.efd, &x, sizeof x);
}
}
-#endif
/**
- * Main processing loop of threads processing jobs.
- * The loop must be called with the mutex locked
- * and it returns with the mutex locked.
- * @param me the description of the thread to use
- * TODO: how are timeout handled when reentering?
+ * Release the currently held event loop
*/
-static void thread_run(volatile struct thread *me)
+static void evloop_release()
{
- struct thread **prv;
- struct job *job;
-#if !defined(REMOVE_SYSTEMD_EVENT)
- struct evloop *el;
-#endif
+ struct thread *nh, *ct = current_thread;
+
+ if (evloop.holder == ct) {
+ nh = ct->nholder;
+ evloop.holder = nh;
+ if (nh)
+ pthread_cond_signal(nh->cwhold);
+ }
+}
+
+/**
+ * get the eventloop for the current thread
+ */
+static int evloop_get()
+{
+ struct thread *ct = current_thread;
+
+ if (evloop.holder)
+ return evloop.holder == ct;
+
+ ct->nholder = NULL;
+ evloop.holder = ct;
+ return 1;
+}
+
+/**
+ * acquire the eventloop for the current thread
+ */
+static void evloop_acquire()
+{
+ struct thread **pwait, *ct;
+ pthread_cond_t cond;
+
+ /* try to get the evloop */
+ if (!evloop_get()) {
+ /* failed, init waiting state */
+ ct = current_thread;
+ ct->nholder = NULL;
+ ct->cwhold = &cond;
+ pthread_cond_init(&cond, NULL);
+
+ /* queue current thread in holder list */
+ pwait = &evloop.holder;
+ while (*pwait)
+ pwait = &(*pwait)->nholder;
+ *pwait = ct;
+
+ /* wake up the evloop */
+ evloop_wakeup();
+
+ /* wait to acquire the evloop */
+ pthread_cond_wait(&cond, &mutex);
+ pthread_cond_destroy(&cond);
+ }
+}
+/**
+ * Enter the thread
+ * @param me the description of the thread to enter
+ */
+static void thread_enter(volatile struct thread *me)
+{
/* initialize description of itself and link it in the list */
me->tid = pthread_self();
me->stop = 0;
me->waits = 0;
me->upper = current_thread;
- if (!current_thread) {
- started++;
- sig_monitor_init_timeouts();
- }
me->next = threads;
threads = (struct thread*)me;
current_thread = (struct thread*)me;
+}
+
+/**
+ * leave the thread
+ * @param me the description of the thread to leave
+ */
+static void thread_leave()
+{
+ struct thread **prv, *me;
+
+ /* unlink the current thread and cleanup */
+ me = current_thread;
+ prv = &threads;
+ while (*prv != me)
+ prv = &(*prv)->next;
+ *prv = me->next;
+
+ current_thread = me->upper;
+}
+
+/**
+ * Main processing loop of internal threads with processing jobs.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ * TODO: how are timeout handled when reentering?
+ */
+static void thread_run_internal(volatile struct thread *me)
+{
+ struct job *job;
+
+ /* enter thread */
+ thread_enter(me);
/* loop until stopped */
while (!me->stop) {
- /* release the event loop */
- if (current_evloop) {
- __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED);
- __atomic_store_n(¤t_evloop->holder, NULL, __ATOMIC_RELAXED);
- current_evloop = NULL;
- }
+ /* release the current event loop */
+ evloop_release();
/* get a job */
job = job_get();
if (job) {
/* prepare running the job */
- remains++; /* increases count of job that can wait */
job->blocked = 1; /* mark job as blocked */
me->job = job; /* record the job (only for terminate) */
/* release the run job */
job_release(job);
-#if !defined(REMOVE_SYSTEMD_EVENT)
- } else {
- /* no job, check events */
- el = &evloop[0];
- if (el->sdev && !__atomic_load_n(&el->state, __ATOMIC_RELAXED)) {
- /* run the events */
- __atomic_store_n(&el->state, EVLOOP_STATE_LOCK|EVLOOP_STATE_RUN|EVLOOP_STATE_WAIT, __ATOMIC_RELAXED);
- __atomic_store_n(&el->holder, me, __ATOMIC_RELAXED);
- current_evloop = el;
- pthread_mutex_unlock(&mutex);
- sig_monitor(0, evloop_run, el);
- pthread_mutex_lock(&mutex);
- } else {
- /* no job and not events */
- running--;
- if (!running)
- ERROR("Entering job deep sleep! Check your bindings.");
- me->waits = 1;
- pthread_cond_wait(&cond, &mutex);
- me->waits = 0;
- running++;
+ /* no job, check event loop wait */
+ } else if (evloop_get()) {
+ if (evloop.state != 0) {
+ /* busy ? */
+ CRITICAL("Can't enter dispatch while in dispatch!");
+ abort();
}
-#else
- } else if (waitevt) {
- /* no job and not events */
+ /* run the events */
+ evloop.state = EVLOOP_STATE_RUN|EVLOOP_STATE_WAIT;
+ pthread_mutex_unlock(&mutex);
+ sig_monitor(0, evloop_run, NULL);
+ pthread_mutex_lock(&mutex);
+ evloop.state = 0;
+ } else {
+ /* no job and no event loop */
running--;
if (!running)
ERROR("Entering job deep sleep! Check your bindings.");
pthread_cond_wait(&cond, &mutex);
me->waits = 0;
running++;
- } else {
- /* wait for events */
- waitevt = 1;
- pthread_mutex_unlock(&mutex);
- sig_monitor(0, monitored_wait_and_dispatch, get_fdevepoll());
- pthread_mutex_lock(&mutex);
- waitevt = 0;
-#endif
}
}
+ /* cleanup */
+ evloop_release();
+ thread_leave();
+}
- /* release the event loop */
- if (current_evloop) {
- __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED);
- __atomic_store_n(&el->holder, NULL, __ATOMIC_RELAXED);
- current_evloop = NULL;
- }
+/**
+ * Main processing loop of external threads.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ */
+static void thread_run_external(volatile struct thread *me)
+{
+ /* enter thread */
+ thread_enter(me);
- /* unlink the current thread and cleanup */
- prv = &threads;
- while (*prv != me)
- prv = &(*prv)->next;
- *prv = me->next;
- current_thread = me->upper;
- if (!current_thread) {
- sig_monitor_clean_timeouts();
- started--;
- }
+ /* loop until stopped */
+ me->waits = 1;
+ while (!me->stop)
+ pthread_cond_wait(&cond, &mutex);
+ me->waits = 0;
+ thread_leave();
}
/**
- * Entry point for created threads.
- * @param data not used
- * @return NULL
+ * Root for created threads.
*/
-static void *thread_main(void *data)
+static void thread_main()
{
struct thread me;
- pthread_mutex_lock(&mutex);
running++;
- thread_run(&me);
+ started++;
+ sig_monitor_init_timeouts();
+ thread_run_internal(&me);
+ sig_monitor_clean_timeouts();
+ started--;
running--;
+}
+
+/**
+ * Entry point for created threads.
+ * @param data not used
+ * @return NULL
+ */
+static void *thread_starter(void *data)
+{
+ pthread_mutex_lock(&mutex);
+ thread_main();
pthread_mutex_unlock(&mutex);
return NULL;
}
pthread_t tid;
int rc;
- rc = pthread_create(&tid, NULL, thread_main, NULL);
+ rc = pthread_create(&tid, NULL, thread_starter, NULL);
if (rc != 0) {
/* errno = rc; */
WARNING("not able to start thread: %m");
void (*callback)(int, void*),
void *arg)
{
- const char *info;
struct job *job;
int rc;
/* allocates the job */
job = job_create(group, timeout, callback, arg);
- if (!job) {
- errno = ENOMEM;
- info = "out of memory";
+ if (!job)
goto error;
- }
/* check availability */
- if (remains == 0) {
+ if (remains <= 0) {
+ ERROR("can't process job with threads: too many jobs");
errno = EBUSY;
- info = "too many jobs";
goto error2;
}
/* all threads are busy and a new can be started */
rc = start_one_thread();
if (rc < 0 && started == 0) {
- info = "can't start first thread";
+ ERROR("can't start initial thread: %m");
goto error2;
}
}
/* queues the job */
- remains--;
job_add(job);
/* signal an existing job */
job->next = free_jobs;
free_jobs = job;
error:
- ERROR("can't process job with threads: %s, %m", info);
pthread_mutex_unlock(&mutex);
return -1;
}
/* allocates the job */
job = job_create(group, timeout, sync_cb, sync);
if (!job) {
- ERROR("out of memory");
- errno = ENOMEM;
pthread_mutex_unlock(&mutex);
return -1;
}
job_add(job);
/* run until stopped */
- thread_run(&sync->thread);
+ if (current_thread)
+ thread_run_internal(&sync->thread);
+ else
+ thread_run_external(&sync->thread);
pthread_mutex_unlock(&mutex);
return 0;
}
return do_sync(group, timeout, enter_cb, &sync);
}
-/**
- * Internal callback for evloop management.
- * The effect of this function is hidden: it exits
- * the waiting poll if any. Then it wakes up a thread
- * awaiting the evloop using signal.
- */
-static int on_evloop_efd(sd_event_source *s, int fd, uint32_t revents, void *userdata)
-{
- uint64_t x;
- struct evloop *evloop = userdata;
- read(evloop->efd, &x, sizeof x);
- pthread_mutex_lock(&mutex);
- pthread_cond_broadcast(&evloop->cond);
- pthread_mutex_unlock(&mutex);
- return 1;
-}
-
-/**
- * unlock the event loop if needed by sending
- * an event.
- * @param el the event loop to unlock
- * @param wait wait the unlocked state of the event loop
- */
-static void unlock_evloop(struct evloop *el, int wait)
-{
- /* wait for a modifiable event loop */
- while (__atomic_load_n(&el->state, __ATOMIC_RELAXED) & EVLOOP_STATE_WAIT) {
- uint64_t x = 1;
- write(el->efd, &x, sizeof x);
- if (!wait)
- break;
- pthread_cond_wait(&el->cond, &mutex);
- }
-}
-
/**
* Unlocks the execution flow designed by 'jobloop'.
* @param jobloop indication of the flow to unlock
int jobs_leave(struct jobloop *jobloop)
{
struct thread *t;
- int i;
pthread_mutex_lock(&mutex);
t = threads;
t->stop = 1;
if (t->waits)
pthread_cond_broadcast(&cond);
- else {
- i = (int)(sizeof evloop / sizeof *evloop);
- while(i) {
- if (evloop[--i].holder == t) {
- unlock_evloop(&evloop[i], 0);
- break;
- }
- }
- }
+ else
+ evloop_wakeup();
}
pthread_mutex_unlock(&mutex);
return -!t;
return do_sync(group, timeout, call_cb, &sync);
}
-/* temporary hack */
-#if !defined(REMOVE_SYSTEMD_EVENT)
-__attribute__((unused))
-#endif
-static void evloop_callback(void *arg, uint32_t event, struct fdev *fdev)
+/**
+ * Internal callback for evloop management.
+ * The effect of this function is hidden: it exits
+ * the waiting poll if any. Then it wakes up a thread
+ * awaiting the evloop using signal.
+ */
+static int on_evloop_efd(sd_event_source *s, int fd, uint32_t revents, void *userdata)
{
- sig_monitor(0, evloop_run, arg);
+ evloop_on_efd_event();
+ return 1;
}
/**
*/
static struct sd_event *get_sd_event_locked()
{
- struct evloop *el;
int rc;
/* creates the evloop on need */
- el = &evloop[0];
- if (!el->sdev) {
+ if (!evloop.sdev) {
/* start the creation */
- el->state = 0;
+ evloop.state = 0;
/* creates the eventfd for waking up polls */
- el->efd = eventfd(0, EFD_CLOEXEC);
- if (el->efd < 0) {
+ evloop.efd = eventfd(0, EFD_CLOEXEC|EFD_SEMAPHORE);
+ if (evloop.efd < 0) {
ERROR("can't make eventfd for events");
goto error1;
}
/* create the systemd event loop */
- rc = sd_event_new(&el->sdev);
+ rc = sd_event_new(&evloop.sdev);
if (rc < 0) {
ERROR("can't make new event loop");
goto error2;
}
/* put the eventfd in the event loop */
- rc = sd_event_add_io(el->sdev, NULL, el->efd, EPOLLIN, on_evloop_efd, el);
+ rc = sd_event_add_io(evloop.sdev, NULL, evloop.efd, EPOLLIN, on_evloop_efd, NULL);
if (rc < 0) {
ERROR("can't register eventfd");
-#if !defined(REMOVE_SYSTEMD_EVENT)
- sd_event_unref(el->sdev);
- el->sdev = NULL;
-error2:
- close(el->efd);
-error1:
- return NULL;
- }
-#else
- goto error3;
- }
- /* handle the event loop */
- el->fdev = fdev_epoll_add(get_fdevepoll(), sd_event_get_fd(el->sdev));
- if (!el->fdev) {
- ERROR("can't create fdev");
-error3:
- sd_event_unref(el->sdev);
+ sd_event_unref(evloop.sdev);
+ evloop.sdev = NULL;
error2:
- close(el->efd);
+ close(evloop.efd);
error1:
- memset(el, 0, sizeof *el);
return NULL;
}
- fdev_set_autoclose(el->fdev, 0);
- fdev_set_events(el->fdev, EPOLLIN);
- fdev_set_callback(el->fdev, evloop_callback, el);
-#endif
}
- /* attach the event loop to the current thread */
- if (current_evloop != el) {
- if (current_evloop) {
- __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED);
- __atomic_store_n(¤t_evloop->holder, NULL, __ATOMIC_RELAXED);
- }
- current_evloop = el;
- __atomic_or_fetch(&el->state, EVLOOP_STATE_LOCK, __ATOMIC_RELAXED);
- __atomic_store_n(&el->holder, current_thread, __ATOMIC_RELAXED);
- }
-
- /* wait for a modifiable event loop */
- unlock_evloop(el, 1);
+ /* acquire the event loop */
+ evloop_acquire();
- return el->sdev;
+ return evloop.sdev;
}
/**
struct sd_event *jobs_get_sd_event()
{
struct sd_event *result;
+ struct thread lt;
+
+ /* ensure an existing thread environment */
+ if (!current_thread) {
+ memset(<, 0, sizeof lt);
+ current_thread = <
+ }
+ /* process */
pthread_mutex_lock(&mutex);
result = get_sd_event_locked();
pthread_mutex_unlock(&mutex);
- return result;
-}
-
-#if defined(REMOVE_SYSTEMD_EVENT)
-/**
- * Gets the fdev_epoll item.
- * @return a fdev_epoll or NULL in case of error
- */
-struct fdev_epoll *jobs_get_fdev_epoll()
-{
- struct fdev_epoll *result;
-
- pthread_mutex_lock(&mutex);
- result = get_fdevepoll();
- pthread_mutex_unlock(&mutex);
+ /* release the faked thread environment if needed */
+ if (current_thread == <) {
+ /*
+ * Releasing it is needed because there is no way to guess
+ * when it has to be released really. But here is where it is
+ * hazardous: if the caller modifies the eventloop when it
+ * is waiting, there is no way to make the change effective.
+ * A workaround to achieve that goal is for the caller to
+ * require the event loop a second time after having modified it.
+ */
+ NOTICE("Requiring sd_event loop out of binder callbacks is hazardous!");
+ if (verbose_wants(Log_Level_Info))
+ sig_monitor_dumpstack();
+ evloop_release();
+ current_thread = NULL;
+ }
return result;
}
-#endif
/**
* Enter the jobs processing loop.
int jobs_start(int allowed_count, int start_count, int waiter_count, void (*start)(int signum, void* arg), void *arg)
{
int rc, launched;
- struct thread me;
struct job *job;
assert(allowed_count >= 1);
sd_event_set_watchdog(get_sd_event_locked(), 1);
#endif
- /* start at least one thread */
- launched = 0;
- while ((launched + 1) < start_count) {
+ /* start at least one thread: the current one */
+ launched = 1;
+ while (launched < start_count) {
if (start_one_thread() != 0) {
ERROR("Not all threads can be started");
goto error;
/* queue the start job */
job = job_create(NULL, 0, start, arg);
- if (!job) {
- ERROR("out of memory");
- errno = ENOMEM;
+ if (!job)
goto error;
- }
job_add(job);
- remains--;
/* run until end */
- running++;
- thread_run(&me);
- running--;
+ thread_main();
rc = 0;
error:
pthread_mutex_unlock(&mutex);
Code Review / src / app-framework-binder.git / commitdiff