kill -HUP pid to restart, also mod+R

dwm.c

@@ -249,6 +249,8 @@ static void setup(void);
 static void seturgent(Client *c, int urg);
 static void showhide(Client *c);
 static void sigchld(int unused);
+static void sighup(int unused);
+static void sigterm(int unused);
 static void spawn(const Arg *arg);
 static int stackpos(const Arg *arg);
 static void tag(const Arg *arg);
@@ -314,6 +316,7 @@ static void (*handler[LASTEvent]) (XEvent *) = {
 	[UnmapNotify] = unmapnotify
 };
 static Atom wmatom[WMLast], netatom[NetLast];
+static int restart = 0;
 static int running = 1;
 static Cur *cursor[CurLast];
 static Clr **scheme;
@@ -1393,6 +1396,7 @@ propertynotify(XEvent *e)
 void
 quit(const Arg *arg)
 {
+	if(arg->i) restart = 1;
 	running = 0;
 }
 
@@ -1822,6 +1826,9 @@ setup(void)
 	/* clean up any zombies immediately */
 	sigchld(0);
 
+	signal(SIGHUP, sighup);
+	signal(SIGTERM, sigterm);
+
 	/* init screen */
 	screen = DefaultScreen(dpy);
 	sw = DisplayWidth(dpy, screen);
@@ -1926,6 +1933,20 @@ sigchld(int unused)
 	while (0 < waitpid(-1, NULL, WNOHANG));
 }
 
+void
+sighup(int unused)
+{
+	Arg a = {.i = 1};
+	quit(&a);
+}
+
+void
+sigterm(int unused)
+{
+	Arg a = {.i = 0};
+	quit(&a);
+}
+
 void
 spawn(const Arg *arg)
 {
@@ -2492,6 +2513,7 @@ main(int argc, char *argv[])
 	scan();
 	runAutostart();
 	run();
+	if(restart) execvp(argv[0], argv);
 	cleanup();
 	XCloseDisplay(dpy);
 	return EXIT_SUCCESS;