Make websocket concurrent

Stress tests shown that the module wsj1
wasn't ready to concurrency.

Change-Id: Ia54196f97e9712adf0920b59b188d570f39a6b4f
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 31 insertions, 7 deletions

diff --git a/src/afb-wsj1.c b/src/afb-wsj1.c
index 42d842e2..7a8e0234 100644
--- a/src/afb-wsj1.c
+++ b/src/afb-wsj1.c
@@ -23,6 +23,7 @@
 #include <errno.h>
 #include <string.h>
 #include <stdio.h>
+#include <pthread.h>
 
 #include <json-c/json.h>
 
@@ -77,6 +78,7 @@ struct afb_wsj1
 	struct afb_ws *ws;
 	struct afb_wsj1_msg *messages;
 	struct wsj1_call *calls;
+	pthread_mutex_t mutex;
 };
 
 struct afb_wsj1 *afb_wsj1_create(struct sd_event *eloop, int fd, struct afb_wsj1_itf *itf, void *closure)
@@ -92,6 +94,7 @@ struct afb_wsj1 *afb_wsj1_create(struct sd_event *eloop, int fd, struct afb_wsj1
 	result->refcount = 1;
 	result->itf = itf;
 	result->closure = closure;
+	pthread_mutex_init(&result->mutex, NULL);
 
 	result->tokener = json_tokener_new();
 	if (result->tokener == NULL)
@@ -114,13 +117,13 @@ error:
 
 void afb_wsj1_addref(struct afb_wsj1 *wsj1)
 {
-	if (wsj1 != NULL)
-		wsj1->refcount++;
+	if (wsj1)
+		__atomic_add_fetch(&wsj1->refcount, 1, __ATOMIC_RELAXED);
 }
 
 void afb_wsj1_unref(struct afb_wsj1 *wsj1)
 {
-	if (wsj1 != NULL && !--wsj1->refcount) {
+	if (wsj1 && !__atomic_sub_fetch(&wsj1->refcount, 1, __ATOMIC_RELAXED)) {
 		afb_ws_destroy(wsj1->ws);
 		json_tokener_free(wsj1->tokener);
 		free(wsj1);
@@ -134,9 +137,10 @@ static void wsj1_on_hangup(struct afb_wsj1 *wsj1)
 }
 
 
-static struct wsj1_call *wsj1_call_search(struct afb_wsj1 *wsj1, const char *id, int remove)
+static struct wsj1_call *wsj1_locked_call_search(struct afb_wsj1 *wsj1, const char *id, int remove)
 {
 	struct wsj1_call *r, **p;
+
 	p = &wsj1->calls;
 	while((r = *p) != NULL) {
 		if (strcmp(r->id, id) == 0) {
@@ -146,6 +150,18 @@ static struct wsj1_call *wsj1_call_search(struct afb_wsj1 *wsj1, const char *id,
 		}
 		p = &r->next;
 	}
+
+	return r;
+}
+
+static struct wsj1_call *wsj1_call_search(struct afb_wsj1 *wsj1, const char *id, int remove)
+{
+	struct wsj1_call *r;
+
+	pthread_mutex_lock(&wsj1->mutex);
+	r = wsj1_locked_call_search(wsj1, id, remove);
+	pthread_mutex_unlock(&wsj1->mutex);
+
 	return r;
 }
 
@@ -155,15 +171,17 @@ static struct wsj1_call *wsj1_call_create(struct afb_wsj1 *wsj1, void (*on_reply
 	if (call == NULL)
 		errno = ENOMEM;
 	else {
+		pthread_mutex_lock(&wsj1->mutex);
 		do {
 			if (wsj1->genid == 0)
 				wsj1->genid = 999999;
 			sprintf(call->id, "%d", wsj1->genid--);
-		} while (wsj1_call_search(wsj1, call->id, 0) != NULL);
+		} while (wsj1_locked_call_search(wsj1, call->id, 0) != NULL);
 		call->callback = on_reply;
 		call->closure = closure;
 		call->next = wsj1->calls;
 		wsj1->calls = call;
+		pthread_mutex_unlock(&wsj1->mutex);
 	}
 	return call;
 }
@@ -301,10 +319,12 @@ static void wsj1_on_text(struct afb_wsj1 *wsj1, char *text, size_t size)
 	msg->refcount = 1;
 	afb_wsj1_addref(wsj1);
 	msg->wsj1 = wsj1;
+	pthread_mutex_lock(&wsj1->mutex);
 	msg->next = wsj1->messages;
 	if (msg->next != NULL)
 		msg->next->previous = msg;
 	wsj1->messages = msg;
+	pthread_mutex_unlock(&wsj1->mutex);
 
 	/* incoke the handler */
 	switch (msg->code) {
@@ -333,19 +353,21 @@ alloc_error:
 void afb_wsj1_msg_addref(struct afb_wsj1_msg *msg)
 {
 	if (msg != NULL)
-		msg->refcount++;
+		__atomic_add_fetch(&msg->refcount, 1, __ATOMIC_RELAXED);
 }
 
 void afb_wsj1_msg_unref(struct afb_wsj1_msg *msg)
 {
-	if (msg != NULL && --msg->refcount == 0) {
+	if (msg != NULL && !__atomic_sub_fetch(&msg->refcount, 1, __ATOMIC_RELAXED)) {
 		/* unlink the message */
+		pthread_mutex_lock(&msg->wsj1->mutex);
 		if (msg->next != NULL)
 			msg->next->previous = msg->previous;
 		if (msg->previous == NULL)
 			msg->wsj1->messages = msg->next;
 		else
 			msg->previous->next = msg->next;
+		pthread_mutex_unlock(&msg->wsj1->mutex);
 		/* free ressources */
 		afb_wsj1_unref(msg->wsj1);
 		json_object_put(msg->object_j);
@@ -363,8 +385,10 @@ struct json_object *afb_wsj1_msg_object_j(struct afb_wsj1_msg *msg)
 {
 	struct json_object *object = msg->object_j;
 	if (object == NULL) {
+		pthread_mutex_lock(&msg->wsj1->mutex);
 		json_tokener_reset(msg->wsj1->tokener);
 		object = json_tokener_parse_ex(msg->wsj1->tokener, msg->object_s, (int)msg->object_s_length);
+		pthread_mutex_unlock(&msg->wsj1->mutex);
 		if (object == NULL) {
 			/* lazy error detection of json request. Is it to improve? */
 			object = json_object_new_string_len(msg->object_s, (int)msg->object_s_length);