Avoid ecpglib core dump with out-of-order operations.

If an application executed operations like EXEC SQL PREPARE
without having first established a database connection, it could
get a core dump instead of the expected clean failure.  This
occurred because we did "pthread_getspecific(actual_connection_key)"
without ever having initialized the TSD key actual_connection_key.
The results of that are probably platform-specific, but at least
on Linux it often leads to a crash.

To fix, add calls to ecpg_pthreads_init() in the code paths that
might use actual_connection_key uninitialized.  It's harmless
(and hopefully inexpensive) to do that more than once.

Per bug #17514 from Okano Naoki.  The problem's ancient, so
back-patch to all supported branches.

Discussion: https://postgr.es/m/17514-edd4fad547c5692c@postgresql.org

diff --git a/src/interfaces/ecpg/ecpglib/connect.c b/src/interfaces/ecpg/ecpglib/connect.c
index ddede01bdd1a5cce01cf8b67b82cbf156b3be195..0cced0d7c6fe032ad19d73153a905ff39272c245 100644 (file)
--- a/src/interfaces/ecpg/ecpglib/connect.c
+++ b/src/interfaces/ecpg/ecpglib/connect.c
@@ -40,6 +40,8 @@ ecpg_get_connection_nr(const char *connection_name)
    if ((connection_name == NULL) || (strcmp(connection_name, "CURRENT") == 0))
    {
 #ifdef ENABLE_THREAD_SAFETY
+       ecpg_pthreads_init();   /* ensure actual_connection_key is valid */
+
        ret = pthread_getspecific(actual_connection_key);
 
        /*
@@ -47,8 +49,7 @@ ecpg_get_connection_nr(const char *connection_name)
         * connection and hope the user knows what they're doing (i.e. using
         * their own mutex to protect that connection from concurrent accesses
         */
-       /* if !ret then  we  got the connection from TSD */
-       if (NULL == ret)
+       if (ret == NULL)
            /* no TSD connection, going for global */
            ret = actual_connection;
 #else
@@ -78,6 +79,8 @@ ecpg_get_connection(const char *connection_name)
    if ((connection_name == NULL) || (strcmp(connection_name, "CURRENT") == 0))
    {
 #ifdef ENABLE_THREAD_SAFETY
+       ecpg_pthreads_init();   /* ensure actual_connection_key is valid */
+
        ret = pthread_getspecific(actual_connection_key);
 
        /*
@@ -85,8 +88,7 @@ ecpg_get_connection(const char *connection_name)
         * connection and hope the user knows what they're doing (i.e. using
         * their own mutex to protect that connection from concurrent accesses
         */
-       /* if !ret then  we  got the connection from TSD */
-       if (NULL == ret)
+       if (ret == NULL)
            /* no TSD connection here either, using global */
            ret = actual_connection;
 #else