Close and reopen fifo on POLLHUP

This fixes the 100% CPU load issue seen in Infix systems when stopping
containers.  We now close and reopen the fifo when the writer end closes
its descriptor.

Also, simplify the code by using open() instead of fopen() + fcntl().

Signed-off-by: Joachim Wiberg <[email protected]>

main.c

@@ -87,7 +87,7 @@ int main(int argc, char *argv[])
 {
 	char msg[1024] = { 0 }, buf[512], *fn, *pidfn = NULL;
 	int create = 0, daemonize = 1, facility = LOG_USER;
-	int partial, fd, flags, c, opts = LOG_PID;
+	int partial, fd, c, opts = LOG_PID;
 	struct pollfd pfd;
 	FILE *fp;
 
@@ -157,17 +157,20 @@ int main(int argc, char *argv[])
 	if (pidfile(pidfn))
 		logit(LOG_ERR, "failed creating pidfile: %s", strerror(errno));
 
-	fp = fopen(fn, "r");
-	if (!fp) {
+reopen:
+	logit(LOG_INFO, "opening fifo %s", fn);
+	fd = open(fn, O_RDONLY | O_NONBLOCK);
+	if (fd == -1) {
 		logit(LOG_ERR, "failed opening %sd: %s", fn, strerror(errno));
 		err(1, "failed opening %s", fn);
 	}
 
-	fd = fileno(fp);
-	flags = fcntl(fd, F_GETFL, 0);
-	if (flags == -1 || fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
-		logit(LOG_ERR, "failed setting pipe fd non-blocking");
-		err(1, "failed setting pipe fd non-blocking");
+	fp = fdopen(fd, "r");
+	if (!fp) {
+		logit(LOG_ERR, "failed opening fifo stream: %s", strerror(errno));
+		close(fd);
+		log_close();
+		exit(1);
 	}
 
 	pfd.fd = fd;
@@ -179,6 +182,11 @@ int main(int argc, char *argv[])
 		int priority = LOG_NOTICE;
 		char *ptr;
 
+		if (pfd.revents & POLLHUP) {
+			fclose(fp);
+			goto reopen;
+		}
+
 		if (!fgets(buf, sizeof(buf), fp))
 			continue;
 		ptr = chomp(buf);