From 6ccfeea2da631f7901e56d655f45210a4e72cb40 Mon Sep 17 00:00:00 2001
From: DL6ER <dl6er@dl6er.de>
Date: Wed, 8 Mar 2017 11:47:58 +0100
Subject: [PATCH] Guarantee FTL's thread safety

---
 FTL.h     |  2 ++
 args.c    |  6 ++++++
 parser.c  | 29 ++++++++++++++++++++---------
 request.c |  7 ++++++-
 socket.c  |  9 +++++++++
 5 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/FTL.h b/FTL.h
index 21ec14a1..3d9340bf 100644
--- a/FTL.h
+++ b/FTL.h
@@ -145,5 +145,7 @@ int setupVarsElements;
 
 bool initialscan;
 bool debug;
+bool debugthreads;
+bool threadlock;
 
 char ** wildcarddomains;
diff --git a/args.c b/args.c
index 2a609a9a..1d7d1a5b 100644
--- a/args.c
+++ b/args.c
@@ -12,12 +12,18 @@
 #include "version.h"
 
 bool debug = false;
+bool threaddebug = false;
 void parse_args(int argc, char* argv[])
 {
 	int i;
 	for(i=0; i < argc; i++) {
 		if(strcmp(argv[i], "debug") == 0)
 			debug = true;
+		if(strcmp(argv[i], "threaddebug") == 0)
+		{
+			debug = true;
+			threaddebug = true;
+		}
 		if(strcmp(argv[i], "test") == 0)
 			killed = 1;
 		if(strcmp(argv[i], "version") == 0)
diff --git a/parser.c b/parser.c
index 9f8a9883..4a421884 100644
--- a/parser.c
+++ b/parser.c
@@ -43,16 +43,27 @@ void *pihole_log_thread(void *val)
 	{
 		int newdata = checkLogForChanges();
 
-		// Process new data if found
-		if(newdata > 0)
+		if(newdata != 0)
 		{
-			process_pihole_log();
-		}
-
-		// Process flushed log
-		else if(newdata < 0)
-		{
-			pihole_log_flushed();
+			// Lock FTL data structure, since it is likely that it will be changed here
+			// Requests should not be processed/answered when data is about to change
+			while(threadlock) sleepms(1);
+			if(debugthreads)
+				logg("Thread lock enabled  (pihole_log_thread)");
+			threadlock = true;
+			// Process new data if found
+			if(newdata > 0)
+			{
+				process_pihole_log();
+			}
+			// Process flushed log
+			else if(newdata < 0)
+			{
+				pihole_log_flushed();
+			}
+			threadlock = false;
+			if(debugthreads)
+				logg("Thread lock disabled (pihole_log_thread)");
 		}
 
 		sleepms(50);
diff --git a/request.c b/request.c
index b2ce994c..dd0c4a39 100644
--- a/request.c
+++ b/request.c
@@ -140,7 +140,12 @@ void process_request(char *client_message, int *sock)
 		if(excludedomains != NULL)
 			clearSetupVarsArray();
 		if(debug)
-			logg_int("Sent top lists data to client, ID: ", *sock);
+		{
+			if(blocked)
+				logg_int("Sent top ads list data to client, ID: ", *sock);
+			else
+				logg_int("Sent top domains list data to client, ID: ", *sock);
+		}
 	}
 	else if(command(client_message, ">top-clients"))
 	{
diff --git a/socket.c b/socket.c
index 758429e5..6aae4e45 100644
--- a/socket.c
+++ b/socket.c
@@ -157,7 +157,16 @@ void *connection_handler_thread(void *socket_desc)
 		{
 			char *message = calloc(strlen(client_message)+1,sizeof(char));
 			strcpy(message, client_message);
+			// Lock FTL data structure, since it is likely that it will be changed here
+			// Requests should not be processed/answered when data is about to change
+			while(threadlock) sleepms(1);
+			threadlock = true;
+			if(debugthreads)
+				logg("Thread lock enabled  (process_request)");
 			process_request(message, &sock);
+			threadlock = false;
+			if(debugthreads)
+				logg("Thread lock disabled (process_request)");
 			free(message);
 			if(sock == 0)
 			{