Switch to poll

epoll doesn't offer any benefit for our use-case. select is old.
Let's just make things consistent and use the portable poll
everywhere.

src/drm.cpp

@@ -10,7 +10,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
-#include <sys/select.h>
+#include <poll.h>
 
 extern "C" {
 #include <wlr/types/wlr_buffer.h>
@@ -270,23 +270,23 @@ static void page_flip_handler(int fd, unsigned int frame,
 
 void flip_handler_thread_run(void)
 {
-	fd_set fds;
-	int ret;
-	drmEventContext evctx = {
-		.version = 2,
-		.page_flip_handler = page_flip_handler,
+	struct pollfd pollfd = {
+		.fd = g_DRM.fd,
+		.events = POLLIN,
 	};
 
-	FD_ZERO(&fds);
-	FD_SET(0, &fds);
-	FD_SET(g_DRM.fd, &fds);
-
 	while ( true )
 	{
-		ret = select(g_DRM.fd + 1, &fds, NULL, NULL, NULL);
-		if (ret < 0) {
+		int ret = poll( &pollfd, 1, -1 );
+		if ( ret < 0 ) {
+			perror( "drm: polling for DRM events failed" );
 			break;
 		}
+
+		drmEventContext evctx = {
+			.version = 2,
+			.page_flip_handler = page_flip_handler,
+		};
 		drmHandleEvent(g_DRM.fd, &evctx);
 	}
 }

src/wlserver.cpp

@@ -7,7 +7,7 @@
 #include <pthread.h>
 #include <stdio.h> 
 #include <string.h> 
-#include <sys/epoll.h>
+#include <poll.h>
 
 #include <map>
 
@@ -613,47 +613,36 @@ void wlserver_unlock(void)
 
 int wlserver_run(void)
 {
-	int epoll_fd = epoll_create( 1 );
-	struct epoll_event ev;
-	struct epoll_event events[128];
-	int n;
-	
-	ev.events = EPOLLIN;
-	
-	if ( epoll_fd == -1 ||
-		epoll_ctl( epoll_fd, EPOLL_CTL_ADD, wlserver.wl_event_loop_fd, &ev ) == -1 )
-	{
-		return 1;
-	}
-
-	while ( run )
-	{
-		n = epoll_wait( epoll_fd, events, 128, -1 );
-		if ( n == -1 )
-		{
+	struct pollfd pollfd = {
+		.fd = wlserver.wl_event_loop_fd,
+		.events = POLLIN,
+	};
+	while ( run ) {
+		int ret = poll( &pollfd, 1, -1 );
+		if ( ret < 0 ) {
 			if ( errno == EINTR )
-			{
 				continue;
-			}
-			else
-			{
-				break;
-			}
+			perror( "wlserver: poll failed" );
+			break;
 		}
 
-		// We have wayland stuff to do, do it while locked
-		wlserver_lock();
-		
-		for ( int i = 0; i < n; i++ )
-		{
+		if ( pollfd.revents & (POLLHUP | POLLERR) ) {
+			fprintf( stderr, "wlserver: socket %s\n", ( pollfd.revents & POLLERR ) ? "error" : "closed" );
+			break;
+		}
+
+		if ( pollfd.revents & POLLIN ) {
+			// We have wayland stuff to do, do it while locked
+			wlserver_lock();
+
 			wl_display_flush_clients(wlserver.wl_display);
 			int ret = wl_event_loop_dispatch(wlserver.wl_event_loop, 0);
 			if (ret < 0) {
 				break;
 			}
-		}
 
-		wlserver_unlock();
+			wlserver_unlock();
+		}
 	}
 
 	// We need to shutdown Xwayland before disconnecting all clients, otherwise