Change config

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.

.gitignore

@@ -0,0 +1,2 @@
+dwm
+*.o

config.h

@@ -0,0 +1,119 @@
+/* See LICENSE file for copyright and license details. */
+
+/* appearance */
+static const unsigned int borderpx  = 1;        /* border pixel of windows */
+static const unsigned int snap      = 32;       /* snap pixel */
+static const int showbar            = 1;        /* 0 means no bar */
+static const int topbar             = 1;        /* 0 means bottom bar */
+static const char *fonts[]          = { "monospace:size=10" };
+static const char dmenufont[]       = "monospace:size=10";
+static const char col_gray1[]       = "#222222";
+static const char col_gray2[]       = "#444444";
+static const char col_gray3[]       = "#bbbbbb";
+static const char col_gray4[]       = "#eeeeee";
+static const char col_cyan[]        = "#005577";
+static const char *colors[][3]      = {
+	/*               fg         bg         border   */
+	[SchemeNorm] = { col_gray3, col_gray1, col_gray2 },
+	[SchemeSel]  = { col_gray4, col_cyan,  col_cyan  },
+};
+
+/* tagging */
+static const char *tags[] = { "1", "2", "3", "4", "5", "6", "7", "8", "9"};
+
+static const Rule rules[] = {
+	/* xprop(1):
+	 *	WM_CLASS(STRING) = instance, class
+	 *	WM_NAME(STRING) = title
+	 */
+	/* class      instance    title       tags mask     isfloating   monitor */
+    { "Virt-viewer", NULL,    NULL,       1 << 8,       0,           -1 },
+};
+
+/* layout(s) */
+static const float mfact     = 0.55; /* factor of master area size [0.05..0.95] */
+static const int nmaster     = 1;    /* number of clients in master area */
+static const int resizehints = 1;    /* 1 means respect size hints in tiled resizals */
+
+static const Layout layouts[] = {
+	/* symbol     arrange function */
+	{ "[]=",      tile },    /* first entry is default */
+	{ "><>",      NULL },    /* no layout function means floating behavior */
+	{ "[M]",      monocle },
+};
+
+/* key definitions */
+#define MODKEY Mod4Mask
+#define TAGKEYS(KEY,TAG) \
+	{ MODKEY,                       KEY,      view,           {.ui = 1 << TAG} }, \
+	{ MODKEY|ControlMask,           KEY,      toggleview,     {.ui = 1 << TAG} }, \
+	{ MODKEY|ShiftMask,             KEY,      tag,            {.ui = 1 << TAG} }, \
+	{ MODKEY|ControlMask|ShiftMask, KEY,      toggletag,      {.ui = 1 << TAG} },
+
+/* helper for spawning shell commands in the pre dwm-5.0 fashion */
+#define SHCMD(cmd) { .v = (const char*[]){ "/bin/sh", "-c", cmd, NULL } }
+
+/* commands */
+static char dmenumon[2] = "0"; /* component of dmenucmd, manipulated in spawn() */
+static const char *dmenucmd[] = { "dmenu_run", "-m", dmenumon, "-fn", dmenufont, "-nb", col_gray1, "-nf", col_gray3, "-sb", col_cyan, "-sf", col_gray4, NULL };
+static const char *termcmd[]  = { "st", NULL };
+
+static Key keys[] = {
+	/* modifier                     key        function        argument */
+	{ MODKEY,                       XK_d,      spawn,          {.v = dmenucmd } },
+	{ MODKEY,                       XK_Return, spawn,          {.v = termcmd } },
+	{ MODKEY,                       XK_j,      focusstack,     {.i = +1 } },
+	{ MODKEY,                       XK_k,      focusstack,     {.i = -1 } },
+	{ MODKEY,                       XK_i,      incnmaster,     {.i = +1 } },
+	{ MODKEY,                       XK_o,      incnmaster,     {.i = -1 } },
+	{ MODKEY,                       XK_h,      setmfact,       {.f = -0.05} },
+	{ MODKEY,                       XK_l,      setmfact,       {.f = +0.05} },
+	{ MODKEY,                       XK_s,      zoom,           {0} },
+	{ MODKEY,                       XK_Tab,    view,           {0} },
+	{ MODKEY|ShiftMask,             XK_q,      killclient,     {0} },
+//	{ MODKEY,                       XK_t,      setlayout,      {.v = &layouts[0]} },
+//	{ MODKEY,                       XK_f,      setlayout,      {.v = &layouts[1]} },
+//	{ MODKEY,                       XK_m,      setlayout,      {.v = &layouts[2]} },
+	{ MODKEY,                       XK_space,  setlayout,      {0} },
+	{ MODKEY|ShiftMask,             XK_space,  togglefloating, {0} },
+	{ MODKEY,                       XK_0,      view,           {.ui = ~0 } },
+	{ MODKEY|ShiftMask,             XK_0,      tag,            {.ui = ~0 } },
+	{ MODKEY,                       XK_comma,  focusmon,       {.i = -1 } },
+	{ MODKEY,                       XK_period, focusmon,       {.i = +1 } },
+	{ MODKEY|ShiftMask,             XK_comma,  tagmon,         {.i = -1 } },
+	{ MODKEY|ShiftMask,             XK_period, tagmon,         {.i = +1 } },
+
+    { MODKEY,                       XK_F1,     spawn,          SHCMD("firefox") },
+    { MODKEY,                       XK_F2,     spawn,          SHCMD("nautilus") },
+    { MODKEY,                       XK_F3,     spawn,          SHCMD("gedit") },
+    { MODKEY,                       XK_F4,     spawn,          SHCMD("idea") },
+
+	TAGKEYS(                        XK_1,                      0)
+	TAGKEYS(                        XK_2,                      1)
+	TAGKEYS(                        XK_3,                      2)
+	TAGKEYS(                        XK_4,                      3)
+	TAGKEYS(                        XK_5,                      4)
+	TAGKEYS(                        XK_6,                      5)
+	TAGKEYS(                        XK_7,                      6)
+	TAGKEYS(                        XK_8,                      7)
+	TAGKEYS(                        XK_9,                      8)
+	{ MODKEY|ShiftMask,             XK_e,      quit,           {0} },
+};
+
+/* button definitions */
+/* click can be ClkTagBar, ClkLtSymbol, ClkStatusText, ClkWinTitle, ClkClientWin, or ClkRootWin */
+static Button buttons[] = {
+	/* click                event mask      button          function        argument */
+	{ ClkLtSymbol,          0,              Button1,        setlayout,      {0} },
+	{ ClkLtSymbol,          0,              Button3,        setlayout,      {.v = &layouts[2]} },
+	{ ClkWinTitle,          0,              Button2,        zoom,           {0} },
+	{ ClkStatusText,        0,              Button2,        spawn,          {.v = termcmd } },
+	{ ClkClientWin,         MODKEY,         Button1,        movemouse,      {0} },
+	{ ClkClientWin,         MODKEY,         Button2,        togglefloating, {0} },
+	{ ClkClientWin,         MODKEY,         Button3,        resizemouse,    {0} },
+	{ ClkTagBar,            0,              Button1,        view,           {0} },
+	{ ClkTagBar,            0,              Button3,        toggleview,     {0} },
+	{ ClkTagBar,            MODKEY,         Button1,        tag,            {0} },
+	{ ClkTagBar,            MODKEY,         Button3,        toggletag,      {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

@@ -169,6 +169,7 @@ static void focus(Client *c);
 static void focusin(XEvent *e);
 static void focusmon(const Arg *arg);
 static void focusstack(const Arg *arg);
+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);
@@ -695,7 +696,7 @@ 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 +705,8 @@ 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 */
+		tw = TEXTW(stext) - lrpad + 2; /* 2px right padding */
-		drw_text(drw, m->ww - sw, 0, sw, bh, 0, stext, 0);
+		drw_text(drw, m->ww - tw, 0, tw, bh, 0, stext, 0);
 	}
 
 	for (c = m->clients; c; c = c->next) {
@@ -728,7 +729,7 @@ 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);
@@ -1520,7 +1521,7 @@ 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);
@@ -1688,10 +1689,12 @@ 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);
+			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);
+			if (ty + HEIGHT(c) < m->wh)
 				ty += HEIGHT(c);
 		}
 }