Follow up to r1675967 (trunk) resp. r1863202 (1.7.x)

resp. r1863211 (1.6.x):
When pool debugging is enabled, make sure we
don't try to emit any debug events after the
debug log file handle has been closed.

Backport of r1675970 from trunk resp. r1863203 from 1.7.x.


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.6.x@1863212 13f79535-47bb-0310-9956-ffa450edef68

Author: rainerjung

memory/unix/apr_pools.c

@@ -636,6 +636,12 @@ static apr_allocator_t *global_allocator = NULL;
 
 #if (APR_POOL_DEBUG & APR_POOL_DEBUG_VERBOSE_ALL)
 static apr_file_t *file_stderr = NULL;
+static apr_status_t apr_pool_cleanup_file_stderr(void *data)
+{
+    file_stderr = NULL;
+    return APR_SUCCESS;
+}
+
 #endif /* (APR_POOL_DEBUG & APR_POOL_DEBUG_VERBOSE_ALL) */
 
 /*
@@ -1706,6 +1712,13 @@ APR_DECLARE(apr_status_t) apr_pool_initialize(void)
     file_stderr = debug_log;
 
     if (file_stderr) {
+        /* Add a cleanup handler that sets the debug log file handle
+         * to NULL, otherwise we'll try to log the global pool
+         * destruction event with predictably disastrous results. */
+        apr_pool_cleanup_register(global_pool, NULL,
+                                  apr_pool_cleanup_file_stderr,
+                                  apr_pool_cleanup_null);
+
         apr_file_printf(file_stderr,
             "POOL DEBUG: [PID"
 #if APR_HAS_THREADS