Improve handling of pthread_mutex_lock error case

We should really be reporting a useful error along with returning
a valid return code if pthread_mutex_lock() throws an error for
some reason.  Add that and back-patch to 9.0 as the prior patch.

Pointed out by Alvaro Herrera

diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index e607006bd1fb19f9ce260d882b72d5404ddf1abe..0176bd7ef7e41df64ac7adba46c3508ad983e7eb 100644 (file)
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -262,7 +262,11 @@ pqsecure_open_client(PGconn *conn)
 
 #ifdef ENABLE_THREAD_SAFETY
                if (pthread_mutex_lock(&ssl_config_mutex))
-                       return -1;
+               {
+                       printfPQExpBuffer(&conn->errorMessage,
+                                  libpq_gettext("unable to acquire mutex\n"));
+                       return PGRES_POLLING_FAILED;
+               }
 #endif
                /* Create a connection-specific SSL object */
                if (!(conn->ssl = SSL_new(SSL_context)) ||
@@ -1111,7 +1115,11 @@ initialize_SSL(PGconn *conn)
                 */
 #ifdef ENABLE_THREAD_SAFETY
                if (pthread_mutex_lock(&ssl_config_mutex))
+               {
+                       printfPQExpBuffer(&conn->errorMessage,
+                                  libpq_gettext("unable to acquire mutex\n"));
                        return -1;
+               }
 #endif
                if (SSL_CTX_use_certificate_chain_file(SSL_context, fnbuf) != 1)
                {
@@ -1325,7 +1333,11 @@ initialize_SSL(PGconn *conn)
 
 #ifdef ENABLE_THREAD_SAFETY
                if (pthread_mutex_lock(&ssl_config_mutex))
+               {
+                       printfPQExpBuffer(&conn->errorMessage,
+                                  libpq_gettext("unable to acquire mutex\n"));
                        return -1;
+               }
 #endif
                if (SSL_CTX_load_verify_locations(SSL_context, fnbuf, NULL) != 1)
                {