From 71d38b3113f9e7617ec72c712c706242a6f244b2 Mon Sep 17 00:00:00 2001
From: William Brown <firstyear@redhat.com>
Date: Wed, 19 Apr 2017 08:22:12 +1000
Subject: [PATCH 3/4] Ticket 49223 - Fix sds queue locking

Bug Description:  In some cases nspr locks may have allowed a corruption
in the queue to occur.

Fix Description:  Change to pthread mutex, and fix the naming of
the struct members.

https://pagure.io/389-ds-base/issue/49223

Author: wibrown

Review by: ???
---
 src/libsds/include/sds.h      |  2 +-
 src/libsds/sds/queue/queue.c  | 18 ++++++++++--------
 src/libsds/sds/queue/tqueue.c | 16 ++++++++--------
 src/libsds/sds/sds_internal.h |  2 --
 4 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/libsds/include/sds.h b/src/libsds/include/sds.h
index d8d51d1..d8d3089 100644
--- a/src/libsds/include/sds.h
+++ b/src/libsds/include/sds.h
@@ -808,7 +808,7 @@ typedef struct _sds_tqueue {
     /**
      * Lock that protects queue operations.
      */
-    PRLock *trust_e_threadz;
+    pthread_mutex_t lock;
 } sds_tqueue;
 /* Thread safe queue operations. */
 
diff --git a/src/libsds/sds/queue/queue.c b/src/libsds/sds/queue/queue.c
index 3aba012..e8ed2c9 100644
--- a/src/libsds/sds/queue/queue.c
+++ b/src/libsds/sds/queue/queue.c
@@ -39,10 +39,10 @@ sds_queue_enqueue(sds_queue *q, void *elem) {
     sds_log("sds_queue_enqueue", "Queue %p - Queueing ptr %p to %p", q, elem, node);
 #endif
     node->element = elem;
-    node->prev = NULL;
-    node->next = q->tail;
+    node->next = NULL;
+    node->prev = q->tail;
     if (q->tail != NULL) {
-        q->tail->prev = node;
+        q->tail->next = node;
     } else {
         /* If tail is null, head must ALSO be null. */
 #ifdef DEBUG
@@ -78,11 +78,13 @@ sds_queue_dequeue(sds_queue *q, void **elem) {
     }
     sds_queue_node *node = q->head;
     *elem = node->element;
-    q->head = node->prev;
+    q->head = node->next;
     sds_free(node);
     if (q->head == NULL) {
-        // If we have no head node, we also have no tail.
+        /* If we have no head node, we also have no tail. */
         q->tail = NULL;
+    } else {
+        q->head->prev = NULL;
     }
 #ifdef DEBUG
     sds_log("sds_queue_dequeue", "Queue %p - complete head: %p tail: %p", q, q->head, q->tail);
@@ -102,9 +104,9 @@ sds_queue_destroy(sds_queue *q) {
 #endif
     /* Map over the queue and free the elements. */
     sds_queue_node *node = q->head;
-    sds_queue_node *prev = NULL;
+    sds_queue_node *next = NULL;
     while (node != NULL) {
-        prev = node->prev;
+        next = node->next;
         if (q->value_free_fn != NULL) {
 #ifdef DEBUG
             sds_log("sds_queue_destroy", "Queue %p - implicitly freeing %p", q, node->element);
@@ -112,7 +114,7 @@ sds_queue_destroy(sds_queue *q) {
             q->value_free_fn(node->element);
         }
         sds_free(node);
-        node = prev;
+        node = next;
     }
     sds_free(q);
     return SDS_SUCCESS;
diff --git a/src/libsds/sds/queue/tqueue.c b/src/libsds/sds/queue/tqueue.c
index 0e75d22..bbbed92 100644
--- a/src/libsds/sds/queue/tqueue.c
+++ b/src/libsds/sds/queue/tqueue.c
@@ -30,32 +30,32 @@ sds_tqueue_init(sds_tqueue **q_ptr, void (*value_free_fn)(void *value)) {
         sds_free(*q_ptr);
         return result;
     }
-    (*q_ptr)->trust_e_threadz = PR_NewLock();
+    pthread_mutex_init(&(*q_ptr)->lock, NULL);
     return SDS_SUCCESS;
 }
 
 sds_result
 sds_tqueue_enqueue(sds_tqueue *q, void *elem) {
-    PR_Lock(q->trust_e_threadz);
+    pthread_mutex_lock(&(q->lock));
     sds_result result = sds_queue_enqueue(q->uq, elem);
-    PR_Unlock(q->trust_e_threadz);
+    pthread_mutex_unlock(&(q->lock));
     return result;
 }
 
 sds_result
 sds_tqueue_dequeue(sds_tqueue *q, void **elem) {
-    PR_Lock(q->trust_e_threadz);
+    pthread_mutex_lock(&(q->lock));
     sds_result result = sds_queue_dequeue(q->uq, elem);
-    PR_Unlock(q->trust_e_threadz);
+    pthread_mutex_unlock(&(q->lock));
     return result;
 }
 
 sds_result
 sds_tqueue_destroy(sds_tqueue *q) {
-    PR_Lock(q->trust_e_threadz);
+    pthread_mutex_lock(&(q->lock));
     sds_result result = sds_queue_destroy(q->uq);
-    PR_Unlock(q->trust_e_threadz);
-    PR_DestroyLock(q->trust_e_threadz);
+    pthread_mutex_unlock(&(q->lock));
+    pthread_mutex_destroy(&(q->lock));
     sds_free(q);
     return result;
 }
diff --git a/src/libsds/sds/sds_internal.h b/src/libsds/sds/sds_internal.h
index aee25d2..e05f408 100644
--- a/src/libsds/sds/sds_internal.h
+++ b/src/libsds/sds/sds_internal.h
@@ -16,8 +16,6 @@
 #include <stdarg.h> // For va_start / va_end
 #include <inttypes.h> // For PRI*
 #include <string.h> // for memset
-// From NSPR
-#include <prlock.h> // For locking in structs
 // #include <pratom.h> // For atomic increments.
 // We use gcc atomic operations instead.
 #include <prlog.h> // For pr_assert
-- 
1.8.3.1