From f05eefd81e6ddc4911529b2c3a754aa68e713ca7 Mon Sep 17 00:00:00 2001
From: Pierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Date: Tue, 16 Mar 2010 18:44:33 -0400
Subject: [PATCH] ustd: update ustd signal handling to avoid wakeups every 100
 ms

---
 libustcomm/ustcomm.c | 23 +++++++++++++++--------
 ustd/ustd.c          | 38 ++++++++++++++++++++++++++++++++++----
 2 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
index 461766d..155dfd0 100644
--- a/libustcomm/ustcomm.c
+++ b/libustcomm/ustcomm.c
@@ -247,9 +247,13 @@ static int recv_message_fd(int fd, char **recv_buf, int *recv_buf_size, int *rec
 				*recv_buf_size = 0;
 				return 0;
 			}
-			/* real error */
-			PERROR("recv");
-			return -1;
+			else if(errno == EINTR) {
+				return -1;
+			}
+			else {
+				PERROR("recv");
+				return -1;
+			}
 		}
 		if(result == 0) {
 			return 0;
@@ -348,15 +352,18 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 			idx++;
 		}
 
-		while((result = poll(fds, n_fds, timeout)) == -1 && errno == EINTR)
-			/* nothing */;
-		if(result == -1) {
+		result = poll(fds, n_fds, timeout);
+		if(result == -1 && errno == EINTR) {
+			/* That's ok. ustd receives signals to notify it must shutdown. */
+			retval = -1;
+			goto free_conn_table_return;
+		}
+		else if(result == -1) {
 			PERROR("poll");
 			retval = -1;
 			goto free_conn_table_return;
 		}
-
-		if(result == 0) {
+		else if(result == 0) {
 			retval = 0;
 			goto free_conn_table_return;
 		}
diff --git a/ustd/ustd.c b/ustd/ustd.c
index c1dd0cb..ce6f7e2 100644
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -549,9 +549,33 @@ void *consumer_thread(void *arg)
 {
 	struct buffer_info *buf = (struct buffer_info *) arg;
 	struct consumer_thread_args *args = (struct consumer_thread_args *) arg;
+	int result;
+	sigset_t sigset;
 
 	DBG("GOT ARGS: pid %d bufname %s", args->pid, args->bufname);
 
+	/* Block signals that should be handled by the main thread. */
+	result = sigemptyset(&sigset);
+	if(result == -1) {
+		PERROR("sigemptyset");
+		goto end;
+	}
+	result = sigaddset(&sigset, SIGTERM);
+	if(result == -1) {
+		PERROR("sigaddset");
+		goto end;
+	}
+	result = sigaddset(&sigset, SIGINT);
+	if(result == -1) {
+		PERROR("sigaddset");
+		goto end;
+	}
+	result = sigprocmask(SIG_BLOCK, &sigset, NULL);
+	if(result == -1) {
+		PERROR("sigprocmask");
+		goto end;
+	}
+
 	buf = connect_buffer(args->pid, args->bufname);
 	if(buf == NULL) {
 		ERR("failed to connect to buffer");
@@ -693,6 +717,7 @@ int start_ustd(int fd)
 	int result;
 	sigset_t sigset;
 	struct sigaction sa;
+	int timeout = -1;
 
 	result = sigemptyset(&sigset);
 	if(result == -1) {
@@ -701,7 +726,7 @@ int start_ustd(int fd)
 	}
 	sa.sa_handler = sigterm_handler;
 	sa.sa_mask = sigset;
-	sa.sa_flags = SA_RESTART;
+	sa.sa_flags = 0;
 	result = sigaction(SIGTERM, &sa, NULL);
 	if(result == -1) {
 		PERROR("sigaction");
@@ -768,12 +793,16 @@ int start_ustd(int fd)
 		char *recvbuf;
 
 		/* check for requests on our public socket */
-		result = ustcomm_ustd_recv_message(&ustd, &recvbuf, NULL, 100);
-		if(result == -1) {
+		result = ustcomm_ustd_recv_message(&ustd, &recvbuf, NULL, timeout);
+		if(result == -1 && errno == EINTR) {
+			/* Caught signal */
+			printf("Caught signal\n");
+		}
+		else if(result == -1) {
 			ERR("error in ustcomm_ustd_recv_message");
 			goto loop_end;
 		}
-		if(result > 0) {
+		else if(result > 0) {
 			if(!strncmp(recvbuf, "collect", 7)) {
 				pid_t pid;
 				char *bufname;
@@ -810,6 +839,7 @@ int start_ustd(int fd)
 				break;
 			}
 			pthread_mutex_unlock(&active_buffers_mutex);
+			timeout = 100;
 		}
 	}
 
-- 
2.34.1