From 5c8aadc590a7ce851cbbb6dd18e40b6ffcf94ba5 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Tue, 17 Sep 2013 18:38:37 +0200
Subject: [SERVER] Block signals on network threads

---
 src/server/altservers.c |  1 +
 src/server/helper.c     | 12 ++++++++++++
 src/server/helper.h     |  1 +
 src/server/net.c        | 11 ++++++++---
 src/server/server.c     |  3 ++-
 src/server/sockhelper.h |  6 +++---
 src/server/uplink.c     |  1 +
 7 files changed, 28 insertions(+), 7 deletions(-)

(limited to 'src')

diff --git a/src/server/altservers.c b/src/server/altservers.c
index 39132ad..e8ef14c 100644
--- a/src/server/altservers.c
+++ b/src/server/altservers.c
@@ -317,6 +317,7 @@ static void *altservers_main(void *data)
 	struct timespec start, end;
 
 	setThreadName( "altserver-check" );
+	blockNoncriticalSignals();
 	// Init spinlock
 	spin_init( &pendingLock, PTHREAD_PROCESS_PRIVATE );
 	// Init waiting links queue
diff --git a/src/server/helper.c b/src/server/helper.c
index 6c0e822..8070fa0 100644
--- a/src/server/helper.c
+++ b/src/server/helper.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <assert.h>
 #include <sys/prctl.h> // For thread names
+#include <signal.h>
 
 #include "../config.h"
 
@@ -128,3 +129,14 @@ void setThreadName(char *name)
 	if ( strlen( name ) > 16 ) name[16] = '\0';
 	prctl( PR_SET_NAME, (unsigned long)name, 0, 0, 0 );
 }
+
+void blockNoncriticalSignals()
+{
+	sigset_t sigmask;
+    sigemptyset(&sigmask);
+    sigaddset(&sigmask, SIGUSR1);
+    sigaddset(&sigmask, SIGUSR2);
+    sigaddset(&sigmask, SIGHUP);
+    sigaddset(&sigmask, SIGPIPE);
+    pthread_sigmask(SIG_BLOCK, &sigmask, NULL);
+}
diff --git a/src/server/helper.h b/src/server/helper.h
index eb82a00..301a5ea 100644
--- a/src/server/helper.h
+++ b/src/server/helper.h
@@ -17,6 +17,7 @@ void strtolower(char *string);
 void remove_trailing_slash(char *string);
 void trim_right(char * const string);
 void setThreadName(char *name);
+void blockNoncriticalSignals();
 
 static inline int is_same_server(const dnbd3_host_t * const a, const dnbd3_host_t * const b)
 {
diff --git a/src/server/net.c b/src/server/net.c
index cd38205..3e9383d 100644
--- a/src/server/net.c
+++ b/src/server/net.c
@@ -30,6 +30,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <signal.h>
 
 #include "sockhelper.h"
 #include "helper.h"
@@ -46,11 +47,12 @@
 
 static inline char recv_request_header(int sock, dnbd3_request_t *request)
 {
-	int ret;
+	int ret, fails = 0;
 	// Read request header from socket
-	if ( (ret = recv( sock, request, sizeof(*request), MSG_WAITALL )) != sizeof(*request) ) {
-		if ( ret == 0 ) return FALSE;
+	while ( (ret = recv( sock, request, sizeof(*request), MSG_WAITALL )) != sizeof(*request) ) {
+		if ( ret >= 0 || ++fails > 10 ) return FALSE;
 		const int err = errno;
+		if ( err == EAGAIN || err == EINTR ) continue;
 		printf( "[DEBUG] Error receiving request: Could not read message header (%d/%d, e=%d)\n", ret, (int)sizeof(*request), err );
 		return FALSE;
 	}
@@ -134,6 +136,9 @@ void *net_client_handler(void *dnbd3_client)
 
 	dnbd3_server_entry_t server_list[NUMBER_SERVERS];
 
+	// Block some signals not important to this thread
+	blockNoncriticalSignals();
+
 	// Set to zero to make valgrind happy
 	memset( &reply, 0, sizeof(reply) );
 	memset( &payload, 0, sizeof(payload) );
diff --git a/src/server/server.c b/src/server/server.c
index e62c966..51c662b 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -328,11 +328,12 @@ int main(int argc, char *argv[])
 	memlogf( "[INFO] Server is ready..." );
 
 	// +++++++++++++++++++++++++++++++++++++++++++++++++++ main loop
-	while ( 1 ) {
+	while ( !_shutdown ) {
 		len = sizeof(client);
 		fd = accept_any( sockets, socket_count, &client, &len );
 		if ( fd < 0 ) {
 			const int err = errno;
+			if ( err == EINTR || err == EAGAIN ) continue;
 			memlogf( "[ERROR] Client accept failure (err=%d)", err );
 			usleep( 10000 ); // 10ms
 			continue;
diff --git a/src/server/sockhelper.h b/src/server/sockhelper.h
index c20cf8f..4f753c9 100644
--- a/src/server/sockhelper.h
+++ b/src/server/sockhelper.h
@@ -59,10 +59,10 @@ void sock_set_block(int sock);
  */
 inline void sock_set_addr4(char *ip, uint16_t port, struct sockaddr_in *addr)
 {
-	memset(addr, 0, sizeof(*addr));
+	memset( addr, 0, sizeof(*addr) );
 	addr->sin_family = AF_INET; // IPv4
-	addr->sin_addr.s_addr = inet_addr(ip);
-	addr->sin_port = htons(port); // set port number
+	addr->sin_addr.s_addr = inet_addr( ip );
+	addr->sin_port = htons( port ); // set port number
 }
 
 /**
diff --git a/src/server/uplink.c b/src/server/uplink.c
index 67936d5..35bb26b 100644
--- a/src/server/uplink.c
+++ b/src/server/uplink.c
@@ -194,6 +194,7 @@ static void* uplink_mainloop(void *data)
 	assert( link != NULL );
 	assert( link->queueLen == 0 );
 	setThreadName( "idle-uplink" );
+	blockNoncriticalSignals();
 	//
 	fdEpoll = epoll_create( 2 );
 	if ( fdEpoll == -1 ) {
-- 
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