Implement log rotation

src/process.c

@@ -23,6 +23,8 @@
 #include <errno.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
+#include <sys/stat.h>
+#include <signal.h>
 
 struct process
 {
@@ -104,16 +106,21 @@ int process_run_section( int id )
 	return EXIT_FAILURE;
 }
 
-static void redirect_io( int section )
+static const char* logfile_for_section( int section )
 {
-	const char* filename = NULL;
 	switch( section ) {
-		case 0:	filename = "data/logs/webserver.log"; break;
-		case 1:	filename = "data/logs/inbox.log"; break;
-		case 2:	filename = "data/logs/outbox.log"; break;
-		case 5:	filename = "data/logs/fetch.log"; break;
-		case 6:	filename = "data/logs/tor.log"; break;
+		case 0:	return "data/logs/webserver.log";
+		case 1:	return "data/logs/inbox.log";
+		case 2:	return "data/logs/outbox.log";
+		case 5:	return "data/logs/fetch.log";
+		case 6:	return "data/logs/tor.log";
 	}
+	return NULL;
+}
+
+static void redirect_io( int section )
+{
+	const char* filename = logfile_for_section(section);
 
 	if( !filename ) { return; }
 
@@ -161,6 +168,39 @@ void process_stop()
 {
 }
 
+static bool rotate_log( int section )
+{
+	const char* logfile = logfile_for_section(section);
+	if(!logfile) { return false; }
+
+	struct stat s;
+	if( -1 == stat( logfile, &s ) ) { return false; }
+
+	if( s.st_size < 50000000 ) { return false; }
+
+	char buffer1[512];
+	char buffer2[512];
+
+	snprintf( buffer1,sizeof(buffer1), "%s.%d", logfile, 5 );
+	unlink( buffer1 );
+
+	snprintf( buffer2,sizeof(buffer2), "%s.%d", logfile, 4 );
+	rename( buffer2, buffer1 );
+
+	snprintf( buffer1,sizeof(buffer1), "%s.%d", logfile, 3 );
+	rename( buffer1, buffer2 );
+
+	snprintf( buffer1,sizeof(buffer2), "%s.%d", logfile, 2 );
+	rename( buffer2, buffer1 );
+
+	snprintf( buffer1,sizeof(buffer1), "%s.%d", logfile, 1 );
+	rename( buffer1, buffer2 );
+
+	rename( logfile, buffer1 );
+
+	return true;
+}
+
 void process_wait_for_finished()
 {
 	while( !terminate ) {
@@ -183,6 +223,9 @@ void process_wait_for_finished()
 					printf( "Restarting...\n" );
 					process_start_section( section );
 				}
+			} else if( rotate_log( child->section ) ) {
+				// Interrupt child process (Ctrl+C) to force restart with new log file
+				kill( child->pid, SIGINT );
 			}
 		}
 	}