Made statusbar clickable. Sends signal to dwmblocks

Many users new to dwm find themselves caught out by being kicked out to the login manager (dwm crashing) when they open 50+ clients for demonstration purposes. The number of clients reported varies depending on the resolution of the monitor.

The cause of this is due to how the default tile layout calculates the height of the next client based on the position of the previous client. Because clients have a minimum size the (ty) position can exceed that of the window height, resulting in (m->wh - ty) becoming negative. The negative height stored as an unsigned int results in a very large height ultimately resulting in dwm crashing.

This patch adds safeguards to prevent the ty and my positions from exceeding that of the window height.

config.def.h

@@ -103,7 +103,9 @@ static Button buttons[] = {
 	{ ClkLtSymbol,          0,              Button1,        setlayout,      {0} },
 	{ ClkLtSymbol,          0,              Button3,        setlayout,      {.v = &layouts[2]} },
 	{ ClkWinTitle,          0,              Button2,        zoom,           {0} },
-	{ ClkStatusText,        0,              Button2,        spawn,          {.v = termcmd } },
+	{ ClkStatusText,        0,              Button1,        sigdwmblocks,   {.i = 1} },
+	{ ClkStatusText,        0,              Button2,        sigdwmblocks,   {.i = 2} },
+	{ ClkStatusText,        0,              Button3,        sigdwmblocks,   {.i = 3} },
 	{ ClkClientWin,         MODKEY,         Button1,        movemouse,      {0} },
 	{ ClkClientWin,         MODKEY,         Button2,        togglefloating, {0} },
 	{ ClkClientWin,         MODKEY,         Button3,        resizemouse,    {0} },

config.mk

@@ -25,7 +25,7 @@ INCS = -I${X11INC} -I${FREETYPEINC}
 LIBS = -L${X11LIB} -lX11 ${XINERAMALIBS} ${FREETYPELIBS}
 
 # flags
-CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_C_SOURCE=2 -DVERSION=\"${VERSION}\" ${XINERAMAFLAGS}
+CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_C_SOURCE=200809L -DVERSION=\"${VERSION}\" ${XINERAMAFLAGS}
 #CFLAGS   = -g -std=c99 -pedantic -Wall -O0 ${INCS} ${CPPFLAGS}
 CFLAGS   = -std=c99 -pedantic -Wall -Wno-deprecated-declarations -Os ${INCS} ${CPPFLAGS}
 LDFLAGS  = ${LIBS}

dwm.c

@@ -156,6 +156,7 @@ static void clientmessage(XEvent *e);
 static void configure(Client *c);
 static void configurenotify(XEvent *e);
 static void configurerequest(XEvent *e);
+static void copyvalidchars(char *text, char *rawtext);
 static Monitor *createmon(void);
 static void destroynotify(XEvent *e);
 static void detach(Client *c);
@@ -169,6 +170,8 @@ static void focus(Client *c);
 static void focusin(XEvent *e);
 static void focusmon(const Arg *arg);
 static void focusstack(const Arg *arg);
+static int getdwmblockspid();
+static Atom getatomprop(Client *c, Atom prop);
 static int getrootptr(int *x, int *y);
 static long getstate(Window w);
 static int gettextprop(Window w, Atom atom, char *text, unsigned int size);
@@ -205,6 +208,7 @@ static void setup(void);
 static void seturgent(Client *c, int urg);
 static void showhide(Client *c);
 static void sigchld(int unused);
+static void sigdwmblocks(const Arg *arg);
 static void spawn(const Arg *arg);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
@@ -237,6 +241,9 @@ static void zoom(const Arg *arg);
 /* variables */
 static const char broken[] = "broken";
 static char stext[256];
+static char rawstext[256];
+static int dwmblockssig;
+pid_t dwmblockspid = 0;
 static int screen;
 static int sw, sh;           /* X display screen geometry width, height */
 static int bh, blw = 0;      /* bar geometry */
@@ -439,9 +446,25 @@ buttonpress(XEvent *e)
 			arg.ui = 1 << i;
 		} else if (ev->x < x + blw)
 			click = ClkLtSymbol;
-		else if (ev->x > selmon->ww - TEXTW(stext))
+		else if (ev->x > (x = selmon->ww - TEXTW(stext) + lrpad)) {
 			click = ClkStatusText;
-		else
+			char *text = rawstext;
+			int i = -1;
+			char ch;
+			dwmblockssig = 0;
+			while (text[++i]) {
+				if ((unsigned char)text[i] < ' ') {
+					ch = text[i];
+					text[i] = '\0';
+					x += TEXTW(text) - lrpad;
+					text[i] = ch;
+					text += i+1;
+					i = -1;
+					if (x >= ev->x) break;
+					dwmblockssig = ch;
+				}
+			}
+		} else
 			click = ClkWinTitle;
 	} else if ((c = wintoclient(ev->window))) {
 		focus(c);
@@ -627,6 +650,19 @@ configurerequest(XEvent *e)
 	XSync(dpy, False);
 }
 
+void
+copyvalidchars(char *text, char *rawtext)
+{
+	int i = -1, j = 0;
+
+	while(rawtext[++i]) {
+		if ((unsigned char)rawtext[i] >= ' ') {
+			text[j++] = rawtext[i];
+		}
+	}
+	text[j] = '\0';
+}
+
 Monitor *
 createmon(void)
 {
@@ -695,7 +731,7 @@ dirtomon(int dir)
 void
 drawbar(Monitor *m)
 {
-	int x, w, sw = 0;
+	int x, w, tw = 0;
 	int boxs = drw->fonts->h / 9;
 	int boxw = drw->fonts->h / 6 + 2;
 	unsigned int i, occ = 0, urg = 0;
@@ -704,8 +740,8 @@ drawbar(Monitor *m)
 	/* draw status first so it can be overdrawn by tags later */
 	if (m == selmon) { /* status is only drawn on selected monitor */
 		drw_setscheme(drw, scheme[SchemeNorm]);
-		sw = TEXTW(stext) - lrpad + 2; /* 2px right padding */
-		drw_text(drw, m->ww - sw, 0, sw, bh, 0, stext, 0);
+		tw = TEXTW(stext) - lrpad + 2; /* 2px right padding */
+		drw_text(drw, m->ww - tw, 0, tw, bh, 0, stext, 0);
 	}
 
 	for (c = m->clients; c; c = c->next) {
@@ -728,7 +764,7 @@ drawbar(Monitor *m)
 	drw_setscheme(drw, scheme[SchemeNorm]);
 	x = drw_text(drw, x, 0, w, bh, lrpad / 2, m->ltsymbol, 0);
 
-	if ((w = m->ww - sw - x) > bh) {
+	if ((w = m->ww - tw - x) > bh) {
 		if (m->sel) {
 			drw_setscheme(drw, scheme[m == selmon ? SchemeSel : SchemeNorm]);
 			drw_text(drw, x, 0, w, bh, lrpad / 2, m->sel->name, 0);
@@ -871,6 +907,18 @@ getatomprop(Client *c, Atom prop)
 	return atom;
 }
 
+int
+getdwmblockspid()
+{
+	char buf[16];
+	FILE *fp = popen("pidof -s dwmblocks", "r");
+	fgets(buf, sizeof(buf), fp);
+	pid_t pid = strtoul(buf, NULL, 10);
+	pclose(fp);
+	dwmblockspid = pid;
+	return pid != 0 ? 0 : -1;
+}
+
 int
 getrootptr(int *x, int *y)
 {
@@ -1520,7 +1568,7 @@ setmfact(const Arg *arg)
 	if (!arg || !selmon->lt[selmon->sellt]->arrange)
 		return;
 	f = arg->f < 1.0 ? arg->f + selmon->mfact : arg->f - 1.0;
-	if (f < 0.1 || f > 0.9)
+	if (f < 0.05 || f > 0.95)
 		return;
 	selmon->mfact = f;
 	arrange(selmon);
@@ -1636,6 +1684,23 @@ sigchld(int unused)
 	while (0 < waitpid(-1, NULL, WNOHANG));
 }
 
+void
+sigdwmblocks(const Arg *arg)
+{
+	union sigval sv;
+	sv.sival_int = (dwmblockssig << 8) | arg->i;
+	if (!dwmblockspid)
+		if (getdwmblockspid() == -1)
+			return;
+
+	if (sigqueue(dwmblockspid, SIGUSR1, sv) == -1) {
+		if (errno == ESRCH) {
+			if (!getdwmblockspid())
+				sigqueue(dwmblockspid, SIGUSR1, sv);
+		}
+	}
+}
+
 void
 spawn(const Arg *arg)
 {
@@ -1688,11 +1753,13 @@ tile(Monitor *m)
 		if (i < m->nmaster) {
 			h = (m->wh - my) / (MIN(n, m->nmaster) - i);
 			resize(c, m->wx, m->wy + my, mw - (2*c->bw), h - (2*c->bw), 0);
-			my += HEIGHT(c);
+			if (my + HEIGHT(c) < m->wh)
+				my += HEIGHT(c);
 		} else {
 			h = (m->wh - ty) / (n - i);
 			resize(c, m->wx + mw, m->wy + ty, m->ww - mw - (2*c->bw), h - (2*c->bw), 0);
-			ty += HEIGHT(c);
+			if (ty + HEIGHT(c) < m->wh)
+				ty += HEIGHT(c);
 		}
 }
 
@@ -1987,8 +2054,10 @@ updatesizehints(Client *c)
 void
 updatestatus(void)
 {
-	if (!gettextprop(root, XA_WM_NAME, stext, sizeof(stext)))
+	if (!gettextprop(root, XA_WM_NAME, rawstext, sizeof(rawstext)))
 		strcpy(stext, "dwm-"VERSION);
+	else
+		copyvalidchars(stext, rawstext);
 	drawbar(selmon);
 }