X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fjobs.c;h=83ca2ed4e11a23321837f96c6bd47efc36b86278;hb=d9de3cd38b17ad16fb6ad6f74e83f4700c5f2b49;hp=8725d00e6cdd4246e5014ab7b6124ad6bb74ca12;hpb=b48b736097a222fdf8c6f1a33c922ee7d7bcd633;p=src%2Fapp-framework-binder.git

diff --git a/src/jobs.c b/src/jobs.c
index 8725d00e..83ca2ed4 100644
--- a/src/jobs.c
+++ b/src/jobs.c
@@ -1,5 +1,5 @@
 /*
- * 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");
@@ -21,28 +21,27 @@
 #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*);
 
@@ -50,7 +49,7 @@ typedef void (*job_cb_t)(int, void*);
 struct job
 {
 	struct job *next;    /**< link to the next job enqueued */
-	void *group;         /**< group of the request */
+	const void *group;   /**< group of the request */
 	job_cb_t callback;   /**< processing callback */
 	void *arg;           /**< argument */
 	int timeout;         /**< timeout in second for processing the request */
@@ -58,30 +57,21 @@ struct job
 	unsigned dropped: 1; /**< is removed ? */
 };
 
-/** Description of handled event loops */
-struct events
-{
-	struct events *next;
-	struct sd_event *event;
-	uint64_t timeout;
-	unsigned runs: 1;
-};
-
 /** 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 */
-	struct events *events; /**< currently processed job */
 	pthread_t tid;         /**< the thread id */
-	unsigned stop: 1;      /**< stop requested */
-	unsigned lowered: 1;   /**< has a lower same thread */
-	unsigned waits: 1;     /**< is waiting? */
+	volatile unsigned stop: 1;      /**< stop requested */
+	volatile unsigned waits: 1;     /**< is waiting? */
 };
 
 /**
- * Description of synchonous callback
+ * Description of synchronous callback
  */
 struct sync
 {
@@ -99,22 +89,23 @@ struct sync
 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;
+static _Thread_local struct thread *current_thread;
 
 /* 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;
+
 /**
  * Create a new job with the given parameters
  * @param group    the group of the job
@@ -124,7 +115,7 @@ static struct job *free_jobs;
  * @return the created job unblock or NULL when no more memory
  */
 static struct job *job_create(
-		void *group,
+		const void *group,
 		int timeout,
 		job_cb_t callback,
 		void *arg)
@@ -136,12 +127,13 @@ static struct job *job_create(
 	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;
 		}
 	}
@@ -163,7 +155,7 @@ end:
  */
 static void job_add(struct job *job)
 {
-	void *group;
+	const void *group;
 	struct job *ijob, **pjob;
 
 	/* prepare to add */
@@ -182,6 +174,7 @@ static void job_add(struct job *job)
 
 	/* queue the jobs */
 	*pjob = job;
+	remains--;
 }
 
 /**
@@ -193,21 +186,11 @@ static inline struct job *job_get()
 	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->runs)
-		events = events->next;
-	return events;
-}
-
 /**
  * Releases the processed 'job': removes it
  * from the list of jobs and unblock the first
@@ -217,7 +200,7 @@ static inline struct events *events_get()
 static inline void job_release(struct job *job)
 {
 	struct job *ijob, **pjob;
-	void *group;
+	const void *group;
 
 	/* first unqueue the job */
 	pjob = &first_job;
@@ -260,62 +243,130 @@ static void job_cancel(int signum, void *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()
 {
-	struct events *events = arg;
-	if (!signum)
-		sd_event_run(events->event, events->timeout);
+	if (evmgr)
+		evmgr_wakeup(evmgr);
 }
 
 /**
- * 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;
-	struct events *events;
-	uint64_t evto;
+	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);
+		}
+	}
+}
+
+/**
+ * get the eventloop for the current thread
+ */
+static int evloop_get()
+{
+	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->lowered = 0;
 	me->waits = 0;
-	me->upper = current;
-	if (current) {
-		current->lowered = 1;
-		evto = EVENT_TIMEOUT_CHILD;
-	} else {
-		started++;
-		sig_monitor_init_timeouts();
-		evto = EVENT_TIMEOUT_TOP;
-	}
+	me->nholder = 0;
+	me->upper = current_thread;
 	me->next = threads;
 	threads = (struct thread*)me;
-	current = (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 */
-	me->events = NULL;
 	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) */
 
@@ -326,49 +377,66 @@ static void thread_run(volatile struct thread *me)
 
 			/* release the run job */
 			job_release(job);
-
-			/* release event if any */
-			events = me->events;
-			if (events) {
-				events->runs = 0;
-				me->events = NULL;
+		/* 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 */
+			pthread_mutex_unlock(&mutex);
+			sig_monitor(0, (void(*)(int,void*))evmgr_job_run, evmgr);
+			pthread_mutex_lock(&mutex);
 		} else {
-			/* no job, check events */
-			events = events_get();
-			if (events) {
-				/* run the events */
-				events->runs = 1;
-				events->timeout = evto;
-				me->events = events;
-				pthread_mutex_unlock(&mutex);
-				sig_monitor(0, events_call, events);
-				pthread_mutex_lock(&mutex);
-				events->runs = 0;
-				me->events = NULL;
-			} else {
-				/* no job and not events */
-				waiting++;
-				me->waits = 1;
-				pthread_cond_wait(&cond, &mutex);
-				me->waits = 0;
-				waiting--;
-			}
+			/* 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 = me->upper;
-	if (current) {
-		current->lowered = 0;
-	} else {
-		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--;
 }
 
 /**
@@ -376,12 +444,10 @@ static void thread_run(volatile struct thread *me)
  * @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;
 }
@@ -395,7 +461,7 @@ static int start_one_thread()
 	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");
@@ -422,12 +488,11 @@ static int start_one_thread()
  * @return 0 in case of success or -1 in case of error
  */
 int jobs_queue(
-		void *group,
+		const void *group,
 		int timeout,
 		void (*callback)(int, void*),
 		void *arg)
 {
-	const char *info;
 	struct job *job;
 	int rc;
 
@@ -435,31 +500,27 @@ int jobs_queue(
 
 	/* 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 (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 */
@@ -471,7 +532,6 @@ error2:
 	job->next = free_jobs;
 	free_jobs = job;
 error:
-	ERROR("can't process job with threads: %s, %m", info);
 	pthread_mutex_unlock(&mutex);
 	return -1;
 }
@@ -504,7 +564,7 @@ static void call_cb(int signum, void *closure)
  * @see jobs_call, jobs_enter, jobs_leave
  */
 static int do_sync(
-		void *group,
+		const void *group,
 		int timeout,
 		void (*sync_cb)(int signum, void *closure),
 		struct sync *sync
@@ -517,8 +577,6 @@ static int do_sync(
 	/* 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;
 	}
@@ -527,7 +585,10 @@ static int do_sync(
 	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;
 }
@@ -544,11 +605,11 @@ static int do_sync(
  *                 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(
-		void *group,
+		const void *group,
 		int timeout,
 		void (*callback)(int signum, void *closure, struct jobloop *jobloop),
 		void *closure
@@ -580,6 +641,8 @@ int jobs_leave(struct jobloop *jobloop)
 		t->stop = 1;
 		if (t->waits)
 			pthread_cond_broadcast(&cond);
+		else
+			evloop_wakeup();
 	}
 	pthread_mutex_unlock(&mutex);
 	return -!t;
@@ -600,7 +663,7 @@ int jobs_leave(struct jobloop *jobloop)
  * @return 0 in case of success or -1 in case of error
  */
 int jobs_call(
-		void *group,
+		const void *group,
 		int timeout,
 		void (*callback)(int, void*),
 		void *arg)
@@ -614,71 +677,48 @@ int jobs_call(
 }
 
 /**
- * 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;
-	struct thread *me;
-	int rc;
+	struct thread lt;
+
+	/* ensure an existing thread environment */
+	if (!current_thread) {
+		memset(&lt, 0, sizeof lt);
+		current_thread = &lt;
+	}
 
+	/* lock */
 	pthread_mutex_lock(&mutex);
 
-	/* search events on stack */
-	me = current;
-	while (me && !me->events)
-		me = me->upper;
-	if (me)
-		/* return the stacked events */
-		events = me->events;
-	else {
-		/* 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->runs = 0;
-						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) {
-			/* */
-			me = current;
-			if (me) {
-				events->runs = 1;
-				me->events = events;
-			} else {
-				WARNING("event returned for unknown thread!");
-			}
-		}
-	}
+	/* 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 == &lt) {
+		/*
+		 * 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;
+	}
 }
 
 /**
@@ -689,10 +729,9 @@ struct sd_event *jobs_get_sd_event()
  * @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 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);
@@ -704,27 +743,21 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star
 	pthread_mutex_lock(&mutex);
 
 	/* check whether already running */
-	if (current || allowed) {
+	if (current_thread || allowed) {
 		ERROR("thread already started");
 		errno = EINVAL;
 		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;
@@ -733,17 +766,13 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star
 	}
 
 	/* 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);
@@ -811,7 +840,7 @@ void jobs_terminate()
 		head = job->next;
 
 		/* search if job is stacked for current */
-		t = current;
+		t = current_thread;
 		while (t && t->job != job)
 			t = t->upper;
 		if (t) {