Escape double-quotes in strings passed to an event notification script

The string in question will be generated internally by repmgr as a simple
one-line string with no control characters etc., so all that needs to be
escaped at the moment are any double quotes.

Makefile.in

@@ -40,7 +40,7 @@ REPMGR_CLIENT_OBJS = repmgr-client.o \
 	repmgr-action-primary.o repmgr-action-standby.o repmgr-action-witness.o \
 	repmgr-action-bdr.o repmgr-action-cluster.o repmgr-action-node.o \
 	configfile.o log.o strutil.o controldata.o dirutil.o compat.o dbutils.o
-REPMGRD_OBJS = repmgrd.o repmgrd-physical.o repmgrd-bdr.o configfile.o log.o dbutils.o strutil.o controldata.o
+REPMGRD_OBJS = repmgrd.o repmgrd-physical.o repmgrd-bdr.o configfile.o log.o dbutils.o strutil.o controldata.o compat.o
 DATE=$(shell date "+%Y-%m-%d")
 
 repmgr_version.h: repmgr_version.h.in

dbutils.c

@@ -27,7 +27,6 @@
 #include "repmgr.h"
 #include "dbutils.h"
 #include "controldata.h"
-
 #include "dirutil.h"
 
 /* mainly for use by repmgrd */
@@ -3086,6 +3085,7 @@ _create_event(PGconn *conn, t_configuration_options *options, int node_id, char
 		char	   *end_ptr = NULL;
 		int			r = 0;
 
+		log_verbose(LOG_DEBUG, "_create_event(): command is '%s'", options->event_notification_command);
 		/*
 		 * If configuration option 'event_notifications' was provided, check
 		 * if this event is one of the ones listed; if not listed, don't
@@ -3164,8 +3164,14 @@ _create_event(PGconn *conn, t_configuration_options *options, int node_id, char
 						src_ptr++;
 						if (details != NULL)
 						{
-							strlcpy(dst_ptr, details, end_ptr - dst_ptr);
+							PQExpBufferData details_escaped;
+							initPQExpBuffer(&details_escaped);
+
+							escape_double_quotes(details, &details_escaped);
+
+							strlcpy(dst_ptr, details_escaped.data, end_ptr - dst_ptr);
 							dst_ptr += strlen(dst_ptr);
+							termPQExpBuffer(&details_escaped);
 						}
 						break;
 					case 's':

repmgrd-bdr.c

@@ -472,8 +472,8 @@ do_bdr_failover(NodeInfoList *nodes, t_node_info *monitored_node)
 	 * event "bdr_failover"
 	 */
 
-	create_event_notification_extended(
-									   next_node_conn,
+
+	create_event_notification_extended(next_node_conn,
 									   &config_file_options,
 									   monitored_node->node_id,
 									   "bdr_failover",

strutil.c

@@ -369,6 +369,31 @@ escape_string(PGconn *conn, const char *string)
 }
 
 
+/*
+ * simple function to escape double quotes only
+ */
+
+void
+escape_double_quotes(char *string, PQExpBufferData *out)
+{
+	char *ptr;
+
+	for (ptr = string; *ptr; ptr++)
+	{
+		if (*ptr == '"')
+		{
+			if ( (ptr == string) || (ptr > string && *(ptr - 1) != '\\'))
+			{
+				appendPQExpBufferChar(out, '\\');
+			}
+		}
+		appendPQExpBufferChar(out, *ptr);
+	}
+
+	return;
+}
+
+
 char *
 string_skip_prefix(const char *prefix, char *string)
 {

strutil.h

@@ -142,6 +142,8 @@ extern char *escape_recovery_conf_value(const char *src);
 
 extern char *escape_string(PGconn *conn, const char *string);
 
+extern void escape_double_quotes(char *string, PQExpBufferData *out);
+
 extern void
 append_where_clause(PQExpBufferData *where_clause, const char *clause,...)
 __attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));