Index: configure
===================================================================
Cannot display: file marked as a binary type.
svn:mime-type = application/octet-stream
Index: configure.ac
===================================================================
--- configure.ac	(revision 245728)
+++ configure.ac	(working copy)
@@ -619,6 +619,18 @@
 AC_MSG_RESULT(no)
 )
 
+# glibc, AFAIK, is the only C library that makes printing a NULL to a string safe.
+AC_MSG_CHECKING([if your system printf is NULL-safe.])
+AC_RUN_IFELSE(
+	AC_LANG_PROGRAM([#include <stdio.h>],
+		[printf("%s", NULL)]),
+	AC_DEFINE([HAVE_NULLSAFE_PRINTF], 1, [Define to 1 if your C library can safely print NULL to string formats.])
+	AC_MSG_RESULT(yes),
+	AC_MSG_RESULT(no),
+	# It's unlikely an embedded system will have this.
+	AC_MSG_RESULT(unknown)
+)
+
 AST_GCC_ATTRIBUTE(pure)
 AST_GCC_ATTRIBUTE(malloc)
 AST_GCC_ATTRIBUTE(const)
Index: include/asterisk/autoconfig.h.in
===================================================================
--- include/asterisk/autoconfig.h.in	(revision 245728)
+++ include/asterisk/autoconfig.h.in	(working copy)
@@ -591,6 +591,9 @@
 /* Define to 1 if you have the `ntohll' function. */
 #undef HAVE_NTOHLL
 
+/* Define to 1 if your C library can safely print NULL to string formats. */
+#undef HAVE_NULLSAFE_PRINTF
+
 /* Define to 1 if your ODBC library has wide (Unicode) types. */
 #undef HAVE_ODBC_WCHAR
 
Index: res/res_agi.c
===================================================================
--- res/res_agi.c	(revision 245728)
+++ res/res_agi.c	(working copy)
@@ -1006,7 +1006,7 @@
 		return NULL;
 	}
 	agi_commands = store->data;
-	AST_LIST_LOCK(agi_commands);
+	ST_LIST_LOCK(agi_commands);
 	cmd = AST_LIST_REMOVE_HEAD(agi_commands, entry);
 	AST_LIST_UNLOCK(agi_commands);
 	return cmd;
@@ -3014,16 +3014,22 @@
 	ast_join(fullcmd, sizeof(fullcmd), cmd->cmda);
 
 	if (!find_command(cmd->cmda, 1)) {
-#ifdef AST_XML_DOCS
 		*((enum ast_doc_src *) &cmd->docsrc) = AST_STATIC_DOC;
 		if (ast_strlen_zero(cmd->summary) && ast_strlen_zero(cmd->usage)) {
+#ifdef AST_XML_DOCS
 			*((char **) &cmd->summary) = ast_xmldoc_build_synopsis("agi", fullcmd);
 			*((char **) &cmd->usage) = ast_xmldoc_build_description("agi", fullcmd);
 			*((char **) &cmd->syntax) = ast_xmldoc_build_syntax("agi", fullcmd);
 			*((char **) &cmd->seealso) = ast_xmldoc_build_seealso("agi", fullcmd);
 			*((enum ast_doc_src *) &cmd->docsrc) = AST_XML_DOC;
+#elif (!defined(HAVE_NULLSAFE_PRINTF))
+			*((char **) &cmd->summary) = ast_strdup("");
+			*((char **) &cmd->usage) = ast_strdup("");
+			*((char **) &cmd->syntax) = ast_strdup("");
+			*((char **) &cmd->seealso) = ast_strdup("");
+#endif
 		}
-#endif
+
 		cmd->mod = mod;
 		AST_RWLIST_WRLOCK(&agi_commands);
 		AST_LIST_INSERT_TAIL(&agi_commands, cmd, list);
@@ -3266,9 +3272,13 @@
 				"Result: %s\r\n", chan->name, command_id, ami_cmd, resultcode, ami_res);
 		switch(res) {
 		case RESULT_SHOWUSAGE:
-			ast_agi_send(agi->fd, chan, "520-Invalid command syntax.  Proper usage follows:\n");
-			ast_agi_send(agi->fd, chan, "%s", c->usage);
-			ast_agi_send(agi->fd, chan, "520 End of proper usage.\n");
+			if (ast_strlen_zero(c->usage)) {
+				ast_agi_send(agi->fd, chan, "520 Invalid command syntax.  Proper usage not available.\n");
+			} else {
+				ast_agi_send(agi->fd, chan, "520-Invalid command syntax.  Proper usage follows:\n");
+				ast_agi_send(agi->fd, chan, "%s", c->usage);
+				ast_agi_send(agi->fd, chan, "520 End of proper usage.\n");
+			}
 			break;
 		case RESULT_FAILURE:
 			/* They've already given the failure.  We've been hung up on so handle this