/*
- * Copyright (C) 2016, 2017 "IoT.bzh"
+ * Copyright (C) 2016-2019 "IoT.bzh"
* Author José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
#include <stdint.h>
#include <unistd.h>
#include <signal.h>
+#include <string.h>
#include <time.h>
#include <sys/syscall.h>
#include <pthread.h>
#include <errno.h>
#include <assert.h>
+#include <sys/eventfd.h>
#include <systemd/sd-event.h>
#include "jobs.h"
+#include "evmgr.h"
#include "sig-monitor.h"
#include "verbose.h"
-
-#if 0
-#define _alert_ "do you really want to remove monitoring?"
-#define sig_monitor_init_timeouts() ((void)0)
-#define sig_monitor_clean_timeouts() ((void)0)
-#define sig_monitor(to,cb,arg) (cb(0,arg))
-#endif
+#include "systemd.h"
#define EVENT_TIMEOUT_TOP ((uint64_t)-1)
#define EVENT_TIMEOUT_CHILD ((uint64_t)10000)
+struct thread;
+
/** Internal shortcut for callback */
typedef void (*job_cb_t)(int, void*);
unsigned dropped: 1; /**< is removed ? */
};
-/** Description of handled event loops */
-struct events
-{
- struct events *next;
- struct sd_event *event;
- uint64_t timeout;
- enum {
- Available,
- Modifiable,
- Locked
- } state;
-};
-
/** 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 */
- unsigned stop: 1; /**< stop requested */
- unsigned waits: 1; /**< is waiting? */
+ volatile unsigned stop: 1; /**< stop requested */
+ volatile unsigned waits: 1; /**< is waiting? */
+ volatile unsigned leaved: 1; /**< was leaved? */
};
/**
- * Description of synchonous callback
+ * Description of synchronous callback
*/
struct sync
{
void *arg; /**< the argument of the callback */
};
-
/* synchronisation of threads */
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
-/* count allowed, started and waiting threads */
+/* count allowed, started and running threads */
static int allowed = 0; /** allowed count of threads */
static int started = 0; /** started count of threads */
-static int waiting = 0; /** waiting count of threads */
+static int running = 0; /** running count of threads */
static int remains = 0; /** allowed count of waiting jobs */
-static int nevents = 0; /** count of events */
/* list of threads */
static struct thread *threads;
static _Thread_local struct thread *current_thread;
-static _Thread_local struct events *current_events;
/* queue of pending jobs */
static struct job *first_job;
-static struct events *first_events;
static struct job *free_jobs;
+/* event loop */
+static struct evmgr *evmgr;
+
+static void (*exit_handler)();
+
/**
* Create a new job with the given parameters
* @param group the group of the job
if (job)
free_jobs = job->next;
else {
- /* allocation without blocking */
+ /* allocation without blocking */
pthread_mutex_unlock(&mutex);
job = malloc(sizeof *job);
pthread_mutex_lock(&mutex);
if (!job) {
- errno = -ENOMEM;
+ 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;
}
-/**
- * Get the next events to process or NULL if none.
- * @return the first events that isn't running or NULL
- */
-static inline struct events *events_get()
-{
- struct events *events = first_events;
- while (events && events->state != Available)
- events = events->next;
- return events;
-}
-
/**
* Releases the processed 'job': removes it
* from the list of jobs and unblock the first
* flow, isn't used
* @param arg the job to run
*/
+__attribute__((unused))
static void job_cancel(int signum, void *arg)
{
struct job *job = arg;
}
/**
- * Monitored normal callback for events.
- * This function is called by the monitor
- * to run the event loop when the safe environment
- * is set.
- * @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 events_call(int signum, void *arg)
+static void evloop_wakeup()
{
- int rc;
- struct sd_event *se;
- struct events *events = arg;
-
- if (!signum) {
- se = events->event;
- rc = sd_event_prepare(se);
- if (rc < 0) {
- errno = -rc;
- ERROR("sd_event_prepare returned an error (state: %d): %m", sd_event_get_state(events->event));
- } else {
- if (rc == 0) {
- rc = sd_event_wait(se, events->timeout);
- if (rc < 0) {
- errno = -rc;
- ERROR("sd_event_wait returned an error (state: %d): %m", sd_event_get_state(events->event));
- }
- }
+ if (evmgr)
+ evmgr_wakeup(evmgr);
+}
- if (rc > 0) {
- rc = sd_event_dispatch(se);
- if (rc < 0) {
- errno = -rc;
- ERROR("sd_event_dispatch returned an error (state: %d): %m", sd_event_get_state(events->event));
- }
- }
+/**
+ * Release the currently held event loop
+ */
+static void evloop_release()
+{
+ struct thread *nh, *ct = current_thread;
+
+ if (ct && evmgr && evmgr_release_if(evmgr, ct)) {
+ nh = ct->nholder;
+ ct->nholder = 0;
+ if (nh) {
+ evmgr_try_hold(evmgr, nh);
+ pthread_cond_signal(nh->cwhold);
}
}
}
/**
- * 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?
+ * get the eventloop for the current thread
*/
-static void thread_run(volatile struct thread *me)
+static int evloop_get()
{
- struct thread **prv;
- struct job *job;
- struct events *events;
- uint64_t evto;
+ return evmgr && evmgr_try_hold(evmgr, current_thread);
+}
+/**
+ * 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 = evmgr_holder(evmgr);
+ while (pwait->nholder)
+ pwait = pwait->nholder;
+ pwait->nholder = 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)
+{
+ evloop_release();
/* initialize description of itself and link it in the list */
me->tid = pthread_self();
me->stop = 0;
me->waits = 0;
+ me->leaved = 0;
+ me->nholder = 0;
me->upper = current_thread;
- if (current_thread) {
- evto = EVENT_TIMEOUT_CHILD;
- } else {
- started++;
- sig_monitor_init_timeouts();
- evto = EVENT_TIMEOUT_TOP;
- }
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 current event loop */
+ evloop_release();
+
/* get a job */
- job = job_get(first_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) */
sig_monitor(job->timeout, job->callback, job->arg);
pthread_mutex_lock(&mutex);
- /* release event if any */
- events = current_events;
- if (events && events->state == Modifiable) {
- current_events = NULL;
- events->state = Available;
- }
-
/* release the run job */
job_release(job);
- } else {
- /* no job, check events */
- events = current_events;
- if (!events)
- events = events_get();
- else if (events->state == Locked) {
- events = 0;
- WARNING("Loosing an event loop because reentering");
- }
- if (events) {
- /* run the events */
- events->state = Locked;
- events->timeout = evto;
- current_events = events;
- pthread_mutex_unlock(&mutex);
- sig_monitor(0, events_call, events);
- pthread_mutex_lock(&mutex);
- current_events = NULL;
- events->state = Available;
- } else {
- /* no job and not events */
- waiting++;
- me->waits = 1;
- pthread_cond_wait(&cond, &mutex);
- me->waits = 0;
- waiting--;
+ /* no job, check event loop wait */
+ } else if (evloop_get()) {
+ if (!evmgr_can_run(evmgr)) {
+ /* busy ? */
+ CRITICAL("Can't enter dispatch while in dispatch!");
+ abort();
}
+ /* run the events */
+ evmgr_prepare_run(evmgr);
+ pthread_mutex_unlock(&mutex);
+ sig_monitor(0, (void(*)(int,void*))evmgr_job_run, evmgr);
+ pthread_mutex_lock(&mutex);
+ } else {
+ /* no job and no event loop */
+ running--;
+ if (!running)
+ ERROR("Entering job deep sleep! Check your bindings.");
+ me->waits = 1;
+ pthread_cond_wait(&cond, &mutex);
+ me->waits = 0;
+ running++;
}
}
+ /* cleanup */
+ evloop_release();
+ thread_leave();
+}
- /* 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--;
- }
+/**
+ * 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);
+
+ /* loop until stopped */
+ me->waits = 1;
+ while (!me->stop)
+ pthread_cond_wait(&cond, &mutex);
+ me->waits = 0;
+ thread_leave();
+}
+
+/**
+ * Root for created threads.
+ */
+static void thread_main()
+{
+ struct thread me;
+
+ running++;
+ started++;
+ sig_monitor_init_timeouts();
+ thread_run_internal(&me);
+ sig_monitor_clean_timeouts();
+ started--;
+ running--;
}
/**
* @param data not used
* @return NULL
*/
-static void *thread_main(void *data)
+static void *thread_starter(void *data)
{
- struct thread me;
-
pthread_mutex_lock(&mutex);
- thread_run(&me);
+ 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");
* The remaining parameter is the parameter 'arg1'
* given here.
* @param arg The second argument for 'callback'
+ * @param start Allow to start a thread if not zero
* @return 0 in case of success or -1 in case of error
*/
-int jobs_queue(
+static int queue_job(
const void *group,
int timeout,
void (*callback)(int, void*),
- void *arg)
+ void *arg,
+ int start)
{
- 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;
}
/* start a thread if needed */
- if (waiting == 0 && started < allowed) {
+ if (start && running == started && started < allowed) {
/* 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;
}
+/**
+ * Queues a new asynchronous job represented by 'callback' and 'arg'
+ * for the 'group' and the 'timeout'.
+ * Jobs are queued FIFO and are possibly executed in parallel
+ * concurrently except for job of the same group that are
+ * executed sequentially in FIFO order.
+ * @param group The group of the job or NULL when no group.
+ * @param timeout The maximum execution time in seconds of the job
+ * or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ * Its first parameter is either 0 on normal flow
+ * or the signal number that broke the normal flow.
+ * The remaining parameter is the parameter 'arg1'
+ * given here.
+ * @param arg The second argument for 'callback'
+ * @return 0 in case of success or -1 in case of error
+ */
+int jobs_queue(
+ const void *group,
+ int timeout,
+ void (*callback)(int, void*),
+ void *arg)
+{
+ return queue_job(group, timeout, callback, arg, 1);
+}
+
/**
* Internal helper function for 'jobs_enter'.
* @see jobs_enter, jobs_leave
/* 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;
+ if (sync->thread.leaved)
+ return 0;
+ errno = EINTR;
+ return -1;
}
/**
* of interrupted flow, the context 'closure' as given and
* a 'jobloop' reference that must be used when the job is
* terminated to unlock the current execution flow.
- * @param arg the argument to the callback
+ * @param closure the argument to the callback
* @return 0 on success or -1 in case of error
*/
int jobs_enter(
if (!t) {
errno = EINVAL;
} else {
+ t->leaved = 1;
t->stop = 1;
if (t->waits)
pthread_cond_broadcast(&cond);
+ else
+ evloop_wakeup();
}
pthread_mutex_unlock(&mutex);
return -!t;
}
/**
- * Gets a sd_event item for the current thread.
- * @return a sd_event or NULL in case of error
+ * Ensure that the current running thread can control the event loop.
*/
-struct sd_event *jobs_get_sd_event()
+void jobs_acquire_event_manager()
{
- struct events *events;
- int rc;
+ struct thread lt;
+ /* ensure an existing thread environment */
+ if (!current_thread) {
+ memset(<, 0, sizeof lt);
+ current_thread = <
+ }
+
+ /* lock */
pthread_mutex_lock(&mutex);
- /* search events on stack */
- events = current_events;
- if (!events) {
- /* search an available events */
- events = events_get();
- if (!events) {
- /* not found, check if creation possible */
- if (nevents >= allowed) {
- ERROR("not possible to add a new event");
- events = NULL;
- } else {
- events = malloc(sizeof *events);
- if (events && (rc = sd_event_new(&events->event)) >= 0) {
- if (nevents < started || start_one_thread() >= 0) {
- events->state = Available;
- events->next = first_events;
- first_events = events;
- } else {
- ERROR("can't start thread for events");
- sd_event_unref(events->event);
- free(events);
- events = NULL;
- }
- } else {
- if (!events) {
- ERROR("out of memory");
- errno = ENOMEM;
- } else {
- free(events);
- ERROR("creation of sd_event failed: %m");
- events = NULL;
- errno = -rc;
- }
- }
- }
- }
- if (events) {
- events->state = Modifiable;
- if (!current_thread)
- WARNING("event returned for unknown thread!");
- current_events = events;
- }
- }
+ /* creates the evloop on need */
+ if (!evmgr)
+ evmgr_create(&evmgr);
+
+ /* acquire the event loop under lock */
+ if (evmgr)
+ evloop_acquire();
+
+ /* unlock */
pthread_mutex_unlock(&mutex);
- return events ? events->event : NULL;
+
+ /* 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 event manager/loop from outside of binder's callback is hazardous!");
+ if (verbose_wants(Log_Level_Info))
+ sig_monitor_dumpstack();
+ evloop_release();
+ current_thread = NULL;
+ }
}
/**
* @param start The start routine to activate (can't be NULL)
* @return 0 in case of success or -1 in case of error.
*/
-int jobs_start(int allowed_count, int start_count, int waiter_count, void (*start)(int signum))
+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);
goto error;
}
- /* start */
- if (sig_monitor_init() < 0) {
- ERROR("failed to initialise signal handlers");
- goto error;
- }
-
/* records the allowed count */
allowed = allowed_count;
started = 0;
- waiting = 0;
+ running = 0;
remains = waiter_count;
- /* 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, (job_cb_t)start, NULL);
- if (!job) {
- ERROR("out of memory");
- errno = ENOMEM;
+ job = job_create(NULL, 0, start, arg);
+ if (!job)
goto error;
- }
job_add(job);
- remains--;
/* run until end */
- thread_run(&me);
+ thread_main();
rc = 0;
error:
pthread_mutex_unlock(&mutex);
+ if (exit_handler)
+ exit_handler();
return rc;
}
/**
- * Terminate all the threads and cancel all pending jobs.
+ * Exit jobs threads and call handler if not NULL.
*/
-void jobs_terminate()
+void jobs_exit(void (*handler)())
{
- struct job *job, *head, *tail;
- pthread_t me, *others;
struct thread *t;
- int count;
-
- /* how am i? */
- me = pthread_self();
/* request all threads to stop */
pthread_mutex_lock(&mutex);
- allowed = 0;
- /* count the number of threads */
- count = 0;
- t = threads;
- while (t) {
- if (!t->upper && !pthread_equal(t->tid, me))
- count++;
- t = t->next;
- }
-
- /* fill the array of threads */
- others = alloca(count * sizeof *others);
- count = 0;
- t = threads;
- while (t) {
- if (!t->upper && !pthread_equal(t->tid, me))
- others[count++] = t->tid;
- t = t->next;
- }
+ /* set the handler */
+ exit_handler = handler;
/* stops the threads */
t = threads;
/* wait the threads */
pthread_cond_broadcast(&cond);
- pthread_mutex_unlock(&mutex);
- while (count)
- pthread_join(others[--count], NULL);
- pthread_mutex_lock(&mutex);
- /* cancel pending jobs of other threads */
- remains = 0;
- head = first_job;
- first_job = NULL;
- tail = NULL;
- while (head) {
- /* unlink the job */
- job = head;
- head = job->next;
-
- /* search if job is stacked for current */
- t = current_thread;
- while (t && t->job != job)
- t = t->upper;
- if (t) {
- /* yes, relink it at end */
- if (tail)
- tail->next = job;
- else
- first_job = job;
- tail = job;
- job->next = NULL;
- } else {
- /* no cancel the job */
- pthread_mutex_unlock(&mutex);
- sig_monitor(0, job_cancel, job);
- free(job);
- pthread_mutex_lock(&mutex);
- }
- }
+ /* leave */
pthread_mutex_unlock(&mutex);
}
-