check that redisContext is not NULL before using it

daemon/redis.c

@@ -74,6 +74,10 @@ static void json_restore_call(struct redis *r, struct callmaster *m, const str *
 static void redis_pipe(struct redis *r, const char *fmt, ...) {
 	va_list ap;
 
+	if (!r->ctx) {
+		ilog(LOG_ERROR, "Unable to pipe redis command. No redis context");
+		return;
+	}
 	va_start(ap, fmt);
 	redisvAppendCommand(r->ctx, fmt, ap);
 	va_end(ap);
@@ -83,6 +87,10 @@ static redisReply *redis_get(struct redis *r, int type, const char *fmt, ...) {
 	va_list ap;
 	redisReply *ret;
 
+	if (!r->ctx) {
+		ilog(LOG_ERROR, "Unable to get redis reply. No redis context");
+		return NULL;
+	}
 	va_start(ap, fmt);
 	ret = redis_expect(type, redisvCommand(r->ctx, fmt, ap));
 	va_end(ap);
@@ -94,6 +102,10 @@ static int redisCommandNR(redisContext *r, const char *fmt, ...) {
 	redisReply *ret;
 	int i = 0;
 
+	if (!r) {
+		ilog(LOG_ERROR, "Unable to send redis command. No redis context");
+		return -1;
+	}
 	va_start(ap, fmt);
 	ret = redisvCommand(r, fmt, ap);
 	va_end(ap);
@@ -115,6 +127,11 @@ static int redisCommandNR(redisContext *r, const char *fmt, ...) {
 static int redis_check_type(struct redis *r, char *key, char *suffix, char *type) {
 	redisReply *rp;
 
+	if (!r->ctx) {
+		ilog(LOG_ERROR, "Unable to check redis reply type. No redis context");
+		return -1;
+	}
+
 	rp = redisCommand(r->ctx, "TYPE %s%s", key, suffix ? : "");
 	if (!rp)
 		return -1;
@@ -133,6 +150,11 @@ static int redis_check_type(struct redis *r, char *key, char *suffix, char *type
 static void redis_consume(struct redis *r) {
 	redisReply *rp;
 
+	if (!r->ctx) {
+		ilog(LOG_ERROR, "Unable to consume pipelined replies. No redis context");
+		r->pipeline = 0;
+		return;
+	}
 	while (r->pipeline) {
 		if (redisGetReply(r->ctx, (void **) &rp) == REDIS_OK)
 			freeReplyObject(rp);
@@ -291,7 +313,7 @@ void on_redis_notification(redisAsyncContext *actx, void *reply, void *privdata)
 
 	// select the right db for restoring the call
 	if (redisCommandNR(r->ctx, "SELECT %i", r->db)) {
-		if (r->ctx->err)
+		if (r->ctx && r->ctx->err)
 			rlog(LOG_ERROR, "Redis error: %s", r->ctx->errstr);
 		redisFree(r->ctx);
 		r->ctx = NULL;
@@ -1597,7 +1619,8 @@ int redis_restore(struct callmaster *m, struct redis *r) {
 	calls = redis_get(r, REDIS_REPLY_ARRAY, "KEYS *");
 
 	if (!calls) {
-		rlog(LOG_ERR, "Could not retrieve call list from Redis: %s", r->ctx->errstr);
+		rlog(LOG_ERR, "Could not retrieve call list from Redis: %s",
+				r->ctx ? r->ctx->errstr : "No redis context");
 		goto err;
 	}
 
@@ -2049,7 +2072,7 @@ err:
 
 	mutex_unlock(&r->lock);
 	rwlock_unlock_r(&c->master_lock);
-	if (r->ctx->err)
+	if (r->ctx && r->ctx->err)
 		rlog(LOG_ERR, "Redis error: %s", r->ctx->errstr);
 	redisFree(r->ctx);
 	r->ctx = NULL;
@@ -2082,7 +2105,7 @@ err:
 	rwlock_unlock_r(&c->master_lock);
 	mutex_unlock(&r->lock);
 
-	if (r->ctx->err)
+	if (r->ctx && r->ctx->err)
 		rlog(LOG_ERR, "Redis error: %s", r->ctx->errstr);
 	redisFree(r->ctx);
 	r->ctx = NULL;