From f45237ea48631f2d7bc345f27da0f6fac795718b Mon Sep 17 00:00:00 2001
From: dimitri staessens <dimitri.staessens@intec.ugent.be>
Date: Tue, 10 May 2016 15:05:43 +0200
Subject: irmd: added dedicated locks for signaling

it's more robust to use dedicated locks for pthread_cond_signal so no
other threads can be waiting for the mutex.
---
 src/irmd/main.c | 49 ++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 40 insertions(+), 9 deletions(-)

(limited to 'src')

diff --git a/src/irmd/main.c b/src/irmd/main.c
index f8a5f2d5..b660511c 100644
--- a/src/irmd/main.c
+++ b/src/irmd/main.c
@@ -85,6 +85,7 @@ struct reg_name_entry {
         bool   flow_arrived;
 
         pthread_cond_t  acc_signal;
+        pthread_mutex_t acc_lock;
 };
 
 /* keeps track of port_id's between N and N - 1 */
@@ -97,6 +98,7 @@ struct port_map_entry {
         pid_t n_1_pid;
 
         pthread_cond_t  res_signal;
+        pthread_mutex_t res_lock;
 
         enum flow_state state;
 };
@@ -137,6 +139,11 @@ static struct port_map_entry * port_map_entry_create()
                 return NULL;
         }
 
+        if (pthread_mutex_init(&e->res_lock, NULL)) {
+                free(e);
+                return NULL;
+        }
+
         return e;
 }
 
@@ -278,6 +285,11 @@ static struct reg_name_entry * reg_name_entry_create()
                 return NULL;
         }
 
+        if (pthread_mutex_init(&e->acc_lock, NULL)) {
+                free(e);
+                return NULL;
+        }
+
         INIT_LIST_HEAD(&e->next);
 
         return e;
@@ -547,16 +559,17 @@ static int enroll_ipcp(instance_name_t  * api,
                 return -1;
         }
 
-        if (ipcp_enroll(entry->api->id, member, n_1_difs[0])) {
+        pthread_mutex_unlock(&instance->r_lock);
+
+        if (ipcp_enroll(api->id, member, n_1_difs[0])) {
                 LOG_ERR("Could not enroll IPCP.");
+                pthread_mutex_lock(&instance->r_lock);
                 free(entry->dif_name);
                 entry->dif_name = NULL;
                 pthread_mutex_unlock(&instance->r_lock);
                 return -1;
         }
 
-        pthread_mutex_unlock(&instance->r_lock);
-
         LOG_INFO("Enrolled IPCP %s-%d in DIF %s.",
                  api->name, api->id, dif_name);
 
@@ -760,8 +773,14 @@ static struct port_map_entry * flow_accept(pid_t    pid,
         rne->accept       = true;
         rne->flow_arrived = false;
 
+        pthread_mutex_unlock(&instance->r_lock);
+        pthread_mutex_lock(&rne->acc_lock);
+
         while (!rne->flow_arrived)
-                pthread_cond_wait(&rne->acc_signal, &instance->r_lock);
+                pthread_cond_wait(&rne->acc_signal, &rne->acc_lock);
+
+        pthread_mutex_unlock(&rne->acc_lock);
+        pthread_mutex_lock(&instance->r_lock);
 
         pme = get_port_map_entry_n(pid);
         if (pme == NULL) {
@@ -895,8 +914,15 @@ static int flow_alloc_res(int port_id)
                 return 0;
         }
 
+        pthread_mutex_unlock(&instance->r_lock);
+        pthread_mutex_lock(&e->res_lock);
+
         while (true) {
-                pthread_cond_wait(&e->res_signal, &instance->r_lock);
+                pthread_cond_wait(&e->res_signal, &e->res_lock);
+
+                pthread_mutex_unlock(&e->res_lock);
+                pthread_mutex_lock(&instance->r_lock);
+
                 e = get_port_map_entry(port_id);
                 if (e == NULL) {
                         pthread_mutex_unlock(&instance->r_lock);
@@ -983,13 +1009,18 @@ static struct port_map_entry * flow_req_arr(pid_t  pid,
         rne->req_ap_name = strdup(ap_name);
         rne->req_ae_name = strdup(ae_name);
 
+        pthread_mutex_lock(&rne->acc_lock);
+
         rne->flow_arrived = true;
 
         if (pthread_cond_signal(&rne->acc_signal))
                 LOG_ERR("Failed to send signal.");
 
+        pthread_mutex_unlock(&rne->acc_lock);
+
         pthread_mutex_unlock(&instance->r_lock);
 
+
         return pme;
 }
 
@@ -1006,10 +1037,7 @@ static int flow_alloc_reply(int port_id,
                 return -1;
         }
 
-        if (e->state == FLOW_ALLOCATED) {
-                pthread_mutex_unlock(&instance->r_lock);
-                return 0;
-        }
+        pthread_mutex_lock(&e->res_lock);
 
         if (!response)
                 e->state = FLOW_ALLOCATED;
@@ -1019,6 +1047,9 @@ static int flow_alloc_reply(int port_id,
 
         if (pthread_cond_signal(&e->res_signal))
                 LOG_ERR("Failed to send signal.");
+
+        pthread_mutex_unlock(&e->res_lock);
+
         pthread_mutex_unlock(&instance->r_lock);
 
         return 0;
-- 
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