Communicate through a Unix socket instead of a pipe pair

surf.c

@@ -3,6 +3,7 @@
  * To understand surf, start reading main().
  */
 #include <sys/file.h>
+#include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <glib.h>
@@ -187,7 +188,7 @@ static gboolean buttonreleased(GtkWidget *w, GdkEvent *e, Client *c);
 static GdkFilterReturn processx(GdkXEvent *xevent, GdkEvent *event,
                                 gpointer d);
 static gboolean winevent(GtkWidget *w, GdkEvent *e, Client *c);
-static gboolean readpipe(GIOChannel *s, GIOCondition ioc, gpointer unused);
+static gboolean readsock(GIOChannel *s, GIOCondition ioc, gpointer unused);
 static void showview(WebKitWebView *v, Client *c);
 static GtkWidget *createwindow(Client *c);
 static gboolean loadfailedtls(WebKitWebView *v, gchar *uri,
@@ -253,7 +254,7 @@ static char *stylefile;
 static const char *useragent;
 static Parameter *curconfig;
 static int modparams[ParameterLast];
-static int pipein[2], pipeout[2];
+static int spair[2];
 char *argv0;
 
 static ParamName loadtransient[] = {
@@ -359,13 +360,15 @@ setup(void)
 
 	gdkkb = gdk_seat_get_keyboard(gdk_display_get_default_seat(gdpy));
 
-	if (pipe(pipeout) < 0 || pipe(pipein) < 0) {
-		fputs("Unable to create pipes\n", stderr);
+	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, spair) < 0) {
+		fputs("Unable to create sockets\n", stderr);
+		spair[0] = spair[1] = -1;
 	} else {
-		gchanin = g_io_channel_unix_new(pipein[0]);
+		gchanin = g_io_channel_unix_new(spair[0]);
 		g_io_channel_set_encoding(gchanin, NULL, NULL);
+		g_io_channel_set_flags(gchanin, G_IO_FLAG_NONBLOCK, NULL);
 		g_io_channel_set_close_on_unref(gchanin, TRUE);
-		g_io_add_watch(gchanin, G_IO_IN, readpipe, NULL);
+		g_io_add_watch(gchanin, G_IO_IN, readsock, NULL);
 	}
 
 
@@ -1054,8 +1057,8 @@ spawn(Client *c, const Arg *a)
 	if (fork() == 0) {
 		if (dpy)
 			close(ConnectionNumber(dpy));
-		close(pipein[0]);
-		close(pipeout[1]);
+		close(spair[0]);
+		close(spair[1]);
 		setsid();
 		execvp(((char **)a->v)[0], (char **)a->v);
 		fprintf(stderr, "%s: execvp %s", argv0, ((char **)a->v)[0]);
@@ -1089,8 +1092,8 @@ cleanup(void)
 	while (clients)
 		destroyclient(clients);
 
-	close(pipein[0]);
-	close(pipeout[1]);
+	close(spair[0]);
+	close(spair[1]);
 	g_free(cookiefile);
 	g_free(scriptfile);
 	g_free(stylefile);
@@ -1233,30 +1236,26 @@ newview(Client *c, WebKitWebView *rv)
 }
 
 static gboolean
-readpipe(GIOChannel *s, GIOCondition ioc, gpointer unused)
+readsock(GIOChannel *s, GIOCondition ioc, gpointer unused)
 {
-	static char msg[MSGBUFSZ], msgsz;
+	static char msg[MSGBUFSZ];
 	GError *gerr = NULL;
+	gsize msgsz;
 
-	if (g_io_channel_read_chars(s, msg, sizeof(msg), NULL, &gerr) !=
+	if (g_io_channel_read_chars(s, msg, sizeof(msg), &msgsz, &gerr) !=
 	    G_IO_STATUS_NORMAL) {
-		fprintf(stderr, "surf: error reading pipe: %s\n",
-		        gerr->message);
-		g_error_free(gerr);
+		if (gerr) {
+			fprintf(stderr, "surf: error reading socket: %s\n",
+			        gerr->message);
+			g_error_free(gerr);
+		}
 		return TRUE;
 	}
-	if ((msgsz = msg[0]) < 3) {
+	if (msgsz < 2) {
 		fprintf(stderr, "surf: message too short: %d\n", msgsz);
 		return TRUE;
 	}
 
-	switch (msg[2]) {
-	case 'i':
-		close(pipein[1]);
-		close(pipeout[0]);
-		break;
-	}
-
 	return TRUE;
 }
 
@@ -1265,10 +1264,10 @@ initwebextensions(WebKitWebContext *wc, Client *c)
 {
 	GVariant *gv;
 
-	if (!pipeout[0] || !pipein[1])
+	if (spair[1] < 0)
 		return;
 
-	gv = g_variant_new("(ii)", pipeout[0], pipein[1]);
+	gv = g_variant_new("i", spair[1]);
 
 	webkit_web_context_set_web_extensions_initialization_user_data(wc, gv);
 	webkit_web_context_set_web_extensions_directory(wc, WEBEXTDIR);
@@ -1874,15 +1873,18 @@ msgext(Client *c, char type, const Arg *a)
 	static char msg[MSGBUFSZ];
 	int ret;
 
-	if ((ret = snprintf(msg, sizeof(msg), "%c%c%c%c",
-	                    4, c->pageid, type, a->i))
+	if (spair[0] < 0)
+		return;
+
+	if ((ret = snprintf(msg, sizeof(msg), "%c%c%c", c->pageid, type, a->i))
 	    >= sizeof(msg)) {
 		fprintf(stderr, "surf: message too long: %d\n", ret);
 		return;
 	}
 
-	if (pipeout[1] && write(pipeout[1], msg, sizeof(msg)) < 0)
-		fprintf(stderr, "surf: error sending: %.*s\n", ret-2, msg+2);
+	if (send(spair[0], msg, ret, 0) != ret)
+		fprintf(stderr, "surf: error sending: %d%c%d (%dB)\n",
+		        c->pageid, type, a->i, ret);
 }
 
 void