From aeb015becc84a457afd5a5fb82e26dfca0978c83 Mon Sep 17 00:00:00 2001
From: Jose Bollo <jose.bollo@iot.bzh>
Date: Wed, 6 Nov 2019 11:12:16 +0100
Subject: [PATCH] jobs: Fix callsync hanging

The function implementing jobs_enter, used by
implementations of synchronous calls, was not
taking care of waking up a thread. This had the
effect of blocking calls made by an external thread.

Bug-AGL: SPEC-2937

Change-Id: I4bf0265b4c029fb619ef7128824ee9d46a45996e
Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>
---
 src/jobs.c | 88 +++++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 62 insertions(+), 26 deletions(-)

diff --git a/src/jobs.c b/src/jobs.c
index 94bdce86..6bbffc8d 100644
--- a/src/jobs.c
+++ b/src/jobs.c
@@ -493,7 +493,7 @@ static int start_one_thread()
  * @param start    Allow to start a thread if not zero
  * @return 0 in case of success or -1 in case of error
  */
-static int queue_job(
+static int queue_job_internal(
 		const void *group,
 		int timeout,
 		void (*callback)(int, void*),
@@ -501,9 +501,14 @@ static int queue_job(
 		int start)
 {
 	struct job *job;
-	int rc;
+	int rc, busy;
 
-	pthread_mutex_lock(&mutex);
+	/* check availability */
+	if (remains <= 0) {
+		ERROR("can't process job with threads: too many jobs");
+		errno = EBUSY;
+		goto error;
+	}
 
 	/* allocates the job */
 	job = job_create(group, timeout, callback, arg);
@@ -518,31 +523,68 @@ static int queue_job(
 	}
 
 	/* start a thread if needed */
-	if (start && running == started && started < allowed) {
+	busy = running == started;
+	if (start && busy && started < allowed) {
 		/* all threads are busy and a new can be started */
 		rc = start_one_thread();
 		if (rc < 0 && started == 0) {
 			ERROR("can't start initial thread: %m");
 			goto error2;
 		}
+		busy = 0;
 	}
 
 	/* queues the job */
 	job_add(job);
 
-	/* signal an existing job */
+	/* wakeup an evloop if needed */
+	if (busy)
+		evloop_wakeup();
+
 	pthread_cond_signal(&cond);
-	pthread_mutex_unlock(&mutex);
 	return 0;
 
 error2:
 	job->next = free_jobs;
 	free_jobs = job;
 error:
-	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'
+ * @param start    Allow to start a thread if not zero
+ * @return 0 in case of success or -1 in case of error
+ */
+static int queue_job(
+		const void *group,
+		int timeout,
+		void (*callback)(int, void*),
+		void *arg,
+		int start)
+{
+	int rc;
+
+	pthread_mutex_lock(&mutex);
+	rc = queue_job_internal(group, timeout, callback, arg, start);
+	pthread_mutex_unlock(&mutex);
+	return rc;
+
+}
+
 /**
  * Queues a new asynchronous job represented by 'callback' and 'arg'
  * for the 'group' and the 'timeout'.
@@ -603,30 +645,24 @@ static int do_sync(
 		struct sync *sync
 )
 {
-	struct job *job;
+	int rc;
 
 	pthread_mutex_lock(&mutex);
 
-	/* allocates the job */
-	job = job_create(group, timeout, sync_cb, sync);
-	if (!job) {
-		pthread_mutex_unlock(&mutex);
-		return -1;
+	rc = queue_job_internal(group, timeout, sync_cb, sync, 1);
+	if (rc == 0) {
+		/* run until stopped */
+		if (current_thread)
+			thread_run_internal(&sync->thread);
+		else
+			thread_run_external(&sync->thread);
+		if (!sync->thread.leaved) {
+			errno = EINTR;
+			rc = -1;
+		}
 	}
-
-	/* queues the job */
-	job_add(job);
-
-	/* run until stopped */
-	if (current_thread)
-		thread_run_internal(&sync->thread);
-	else
-		thread_run_external(&sync->thread);
 	pthread_mutex_unlock(&mutex);
-	if (sync->thread.leaved)
-		return 0;
-	errno = EINTR;
-	return -1;
+	return rc;
 }
 
 /**
-- 
2.16.6