subx/053new-segment.subx


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90

# Create a new segment (pool of memory for allocating chunks from) in the form
# of an *allocation descriptor* that can be passed to the memory allocator
# (defined in a later layer).
#
# Currently an allocation descriptor consists of just the bounds of the pool of
# available memory:
#
#   curr : address
#   end : address
#
# This isn't enough information to reclaim individual allocations. We can't
# support arbitrary reclamation yet.

== code
#   instruction                     effective address                                                   register    displacement    immediate
# . op          subop               mod             rm32          base        index         scale       r32
# . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes

Entry:   # manual test
    # var ad/ECX : (address allocation-descriptor) = {0, 0}
    68/push  0/imm32/limit
    68/push  0/imm32/curr
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # new-segment(0x1000, ad)
    # . . push args
    51/push-ECX
    68/push  0x1000/imm32
    # . . call
    e8/call  new-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = ad->curr
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    # write to *EAX to check that we have access to the newly-allocated segment
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0x34/imm32        # copy to *EAX
    # syscall(exit, EAX)
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
    b8/copy-to-EAX  1/imm32/exit
    cd/syscall  0x80/imm8

new-segment:  # len : int, ad : (address allocation-descriptor)
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    50/push-EAX
    53/push-EBX
    # copy len to _mmap-new-segment->len
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           0/r32/EAX   8/disp8         .                 # copy *(EBP+8) to EAX
    89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   _mmap-new-segment:len/disp32      # copy EAX to *_mmap-new-segment:len
    # mmap(_mmap-new-segment)
    bb/copy-to-EBX  _mmap-new-segment/imm32
    b8/copy-to-EAX  0x5a/imm32/mmap
    cd/syscall  0x80/imm8
    # copy {EAX, EAX+len} to *ad
    # . EBX = ad
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           3/r32/EBX   0xc/disp8       .                 # copy *(EBP+12) to EBX
    # . *EBX = EAX
    89/copy                         0/mod/indirect  3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to *EBX
    # . *(EBX+4) = EAX+len
    03/add                          1/mod/*+disp8   5/rm32/EBP    .           .             .           0/r32/EAX   8/disp8         .                 # add *(EBP+8) to EAX
    89/copy                         1/mod/*+disp8   3/rm32/EBX    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(EBX+4)
$new-segment:end:
    # . restore registers
    5b/pop-to-EBX
    58/pop-to-EAX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

== data

# various constants used here were found in the Linux sources (search for file mman-common.h)
_mmap-new-segment:  # type mmap_arg_struct
    # addr
    0/imm32
_mmap-new-segment:len:
    # len
    0/imm32
    # protection flags
    3/imm32  # PROT_READ | PROT_WRITE
    # sharing flags
    0x22/imm32  # MAP_PRIVATE | MAP_ANONYMOUS
    # fd
    -1/imm32  # since MAP_ANONYMOUS is specified
    # offset
    0/imm32  # since MAP_ANONYMOUS is specified

# . . vim:nowrap:textwidth=0
/* See LICENSE file for copyright and license details. */
#include "dwm.h"
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/select.h>
#include <X11/cursorfont.h>
#include <X11/keysym.h>
#include <X11/Xatom.h>
#include <X11/Xproto.h>
#include <X11/Xutil.h>

/* extern */

char stext[256];
int screen, sx, sy, sw, sh, wax, way, waw, wah;
unsigned int bh, ntags;
unsigned int bpos = BARPOS;
unsigned int numlockmask = 0;
Atom dwmprops, wmatom[WMLast], netatom[NetLast];
Bool *seltags;
Bool selscreen = True;
Client *clients = NULL;
Client *sel = NULL;
Client *stack = NULL;
Cursor cursor[CurLast];
Display *dpy;
DC dc = {0};
Window root, barwin;

/* static */

static int (*xerrorxlib)(Display *, XErrorEvent *);
static Bool otherwm, readin;
static Bool running = True;

static void
cleanup(void) {
	close(STDIN_FILENO);
	while(stack) {
		unban(stack);
		unmanage(stack, NormalState);
	}
	if(dc.font.set)
		XFreeFontSet(dpy, dc.font.set);
	else
		XFreeFont(dpy, dc.font.xfont);
	XUngrabKey(dpy, AnyKey, AnyModifier, root);
	XFreePixmap(dpy, dc.drawable);
	XFreeGC(dpy, dc.gc);
	XDestroyWindow(dpy, barwin);
	XFreeCursor(dpy, cursor[CurNormal]);
	XFreeCursor(dpy, cursor[CurResize]);
	XFreeCursor(dpy, cursor[CurMove]);
	XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime);
	XSync(dpy, False);
	free(seltags);
}

static unsigned long
initcolor(const char *colstr) {
	Colormap cmap = DefaultColormap(dpy, screen);
	XColor color;

	if(!XAllocNamedColor(dpy, cmap, colstr, &color, &color))
		eprint("error, cannot allocate color '%s'\n", colstr);
	return color.pixel;
}

static void
initfont(const char *fontstr) {
	char *def, **missing;
	int i, n;

	missing = NULL;
	if(dc.font.set)
		XFreeFontSet(dpy, dc.font.set);
	dc.font.set = XCreateFontSet(dpy, fontstr, &missing, &n, &def);
	if(missing) {
		while(n--)
			fprintf(stderr, "dwm: missing fontset: %s\n", missing[n]);
		XFreeStringList(missing);
	}
	if(dc.font.set) {
		XFontSetExtents *font_extents;
		XFontStruct **xfonts;
		char **font_names;
		dc.font.ascent = dc.font.descent = 0;
		font_extents = XExtentsOfFontSet(dc.font.set);
		n = XFontsOfFontSet(dc.font.set, &xfonts, &font_names);
		for(i = 0, dc.font.ascent = 0, dc.font.descent = 0; i < n; i++) {
			if(dc.font.ascent < (*xfonts)->ascent)
				dc.font.ascent = (*xfonts)->ascent;
			if(dc.font.descent < (*xfonts)->descent)
				dc.font.descent = (*xfonts)->descent;
			xfonts++;
		}
	}
	else {
		if(dc.font.xfont)
			XFreeFont(dpy, dc.font.xfont);
		dc.font.xfont = NULL;
		if(!(dc.font.xfont = XLoadQueryFont(dpy, fontstr)))
			eprint("error, cannot load font: '%s'\n", fontstr);
		dc.font.ascent = dc.font.xfont->ascent;
		dc.font.descent = dc.font.xfont->descent;
	}
	dc.font.height = dc.font.ascent + dc.font.descent;
}

static void
scan(void) {
	unsigned int i, num;
	Window *wins, d1, d2;
	XWindowAttributes wa;

	wins = NULL;
	if(XQueryTree(dpy, root, &d1, &d2, &wins, &num)) {
		for(i = 0; i < num; i++) {
			if(!XGetWindowAttributes(dpy, wins[i], &wa)
			|| wa.override_redirect || XGetTransientForHint(dpy, wins[i], &d1))
				continue;
			if(wa.map_state == IsViewable)
				manage(wins[i], &wa);
		}
	}
	if(wins)
		XFree(wins);
}

static void
setup(void) {
	int i, j;
	unsigned int mask;
	Window w;
	XModifierKeymap *modmap;
	XSetWindowAttributes wa;

	/* init atoms */
	dwmprops = XInternAtom(dpy, "_DWM_PROPERTIES", False);
	wmatom[WMProtocols] = XInternAtom(dpy, "WM_PROTOCOLS", False);
	wmatom[WMDelete] = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
	wmatom[WMName] = XInternAtom(dpy, "WM_NAME", False);
	wmatom[WMState] = XInternAtom(dpy, "WM_STATE", False);
	netatom[NetSupported] = XInternAtom(dpy, "_NET_SUPPORTED", False);
	netatom[NetWMName] = XInternAtom(dpy, "_NET_WM_NAME", False);
	XChangeProperty(dpy, root, netatom[NetSupported], XA_ATOM, 32,
			PropModeReplace, (unsigned char *) netatom, NetLast);
	/* init cursors */
	cursor[CurNormal] = XCreateFontCursor(dpy, XC_left_ptr);
	cursor[CurResize] = XCreateFontCursor(dpy, XC_sizing);
	cursor[CurMove] = XCreateFontCursor(dpy, XC_fleur);
	/* init modifier map */
	modmap = XGetModifierMapping(dpy);
	for (i = 0; i < 8; i++)
		for (j = 0; j < modmap->max_keypermod; j++) {
			if(modmap->modifiermap[i * modmap->max_keypermod + j]
					== XKeysymToKeycode(dpy, XK_Num_Lock))
				numlockmask = (1 << i);
		}
	XFreeModifiermap(modmap);
	/* select for events */
	wa.event_mask = SubstructureRedirectMask | SubstructureNotifyMask
		| EnterWindowMask | LeaveWindowMask | StructureNotifyMask;
	wa.cursor = cursor[CurNormal];
	XChangeWindowAttributes(dpy, root, CWEventMask | CWCursor, &wa);
	XSelectInput(dpy, root, wa.event_mask);
	grabkeys();
	compileregs();
	for(ntags = 0; tags[ntags]; ntags++);
	seltags = emallocz(sizeof(Bool) * ntags);
	seltags[0] = True;
	/* style */
	dc.norm[ColBorder] = initcolor(NORMBORDERCOLOR);
	dc.norm[ColBG] = initcolor(NORMBGCOLOR);
	dc.norm[ColFG] = initcolor(NORMFGCOLOR);
	dc.sel[ColBorder] = initcolor(SELBORDERCOLOR);
	dc.sel[ColBG] = initcolor(SELBGCOLOR);
	dc.sel[ColFG] = initcolor(SELFGCOLOR);
	initfont(FONT);
	/* geometry */
	sx = sy = 0;
	sw = DisplayWidth(dpy, screen);
	sh = DisplayHeight(dpy, screen);
	initlayouts();
	/* bar */
	dc.h = bh = dc.font.height + 2;
	wa.override_redirect = 1;
	wa.background_pixmap = ParentRelative;
	wa.event_mask = ButtonPressMask | ExposureMask;
	barwin = XCreateWindow(dpy, root, sx, sy, sw, bh, 0,
			DefaultDepth(dpy, screen), CopyFromParent, DefaultVisual(dpy, screen),
			CWOverrideRedirect | CWBackPixmap | CWEventMask, &wa);
	XDefineCursor(dpy, barwin, cursor[CurNormal]);
	updatebarpos();
	XMapRaised(dpy, barwin);
	strcpy(stext, "dwm-"VERSION);
	/* pixmap for everything */
	dc.drawable = XCreatePixmap(dpy, root, sw, bh, DefaultDepth(dpy, screen));
	dc.gc = XCreateGC(dpy, root, 0, 0);
	XSetLineAttributes(dpy, dc.gc, 1, LineSolid, CapButt, JoinMiter);
	if(!dc.font.set)
		XSetFont(dpy, dc.gc, dc.font.xfont->fid);
	/* multihead support */
	selscreen = XQueryPointer(dpy, root, &w, &w, &i, &i, &i, &i, &mask);
	getdwmprops();
}

/*
 * Startup Error handler to check if another window manager
 * is already running.
 */
static int
xerrorstart(Display *dsply, XErrorEvent *ee) {
	otherwm = True;
	return -1;
}

/* extern */

Bool
gettextprop(Window w, Atom atom, char *text, unsigned int size) {
	char **list = NULL;
	int n;
	XTextProperty name;

	if(!text || size == 0)
		return False;
	text[0] = '\0';
	XGetTextProperty(dpy, w, &name, atom);
	if(!name.nitems)
		return False;
	if(name.encoding == XA_STRING)
		strncpy(text, (char *)name.value, size - 1);
	else {
		if(XmbTextPropertyToTextList(dpy, &name, &list, &n) >= Success
		&& n > 0 && *list)
		{
			strncpy(text, *list, size - 1);
			XFreeStringList(list);
		}
	}
	text[size - 1] = '\0';
	XFree(name.value);
	return True;
}

void
quit(const char *arg) {
	readin = running = False;
}

/* There's no way to check accesses to destroyed windows, thus those cases are
 * ignored (especially on UnmapNotify's).  Other types of errors call Xlibs
 * default error handler, which may call exit.
 */
int
xerror(Display *dpy, XErrorEvent *ee) {
	if(ee->error_code == BadWindow
	|| (ee->request_code == X_SetInputFocus && ee->error_code == BadMatch)
	|| (ee->request_code == X_PolyText8 && ee->error_code == BadDrawable)
	|| (ee->request_code == X_PolyFillRectangle && ee->error_code == BadDrawable)
	|| (ee->request_code == X_PolySegment && ee->error_code == BadDrawable)
	|| (ee->request_code == X_ConfigureWindow && ee->error_code == BadMatch)
	|| (ee->request_code == X_GrabKey && ee->error_code == BadAccess)
	|| (ee->request_code == X_CopyArea && ee->error_code == BadDrawable))
		return 0;
	fprintf(stderr, "dwm: fatal error: request code=%d, error code=%d\n",
		ee->request_code, ee->error_code);
	return xerrorxlib(dpy, ee); /* may call exit */
}

int
main(int argc, char *argv[]) {
	char *p;
	int r, xfd;
	fd_set rd;
	XEvent ev;

	if(argc == 2 && !strcmp("-v", argv[1]))
		eprint("dwm-"VERSION", © 2006-2007 A. R. Garbe, S. van Dijk, J. Salmi, P. Hruby, S. Nagy\n");
	else if(argc != 1)
		eprint("usage: dwm [-v]\n");
	setlocale(LC_CTYPE, "");
	if(!(dpy = XOpenDisplay(0)))
		eprint("dwm: cannot open display\n");
	xfd = ConnectionNumber(dpy);
	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);
	otherwm = False;
	XSetErrorHandler(xerrorstart);
	/* this causes an error if some other window manager is running */
	XSelectInput(dpy, root, SubstructureRedirectMask);
	XSync(dpy, False);
	if(otherwm)
		eprint("dwm: another window manager is already running\n");

	XSync(dpy, False);
	XSetErrorHandler(NULL);
	xerrorxlib = XSetErrorHandler(xerror);
	XSync(dpy, False);
	setup();
	drawstatus();
	scan();

	/* main event loop, also reads status text from stdin */
	XSync(dpy, False);
	readin = True;
	while(running) {
		FD_ZERO(&rd);
		if(readin)
			FD_SET(STDIN_FILENO, &rd);
		FD_SET(xfd, &rd);
		if(select(xfd + 1, &rd, NULL, NULL, NULL) == -1) {
			if(errno == EINTR)
				continue;
			eprint("select failed\n");
		}
		if(FD_ISSET(STDIN_FILENO, &rd)) {
			switch(r = read(STDIN_FILENO, stext, sizeof stext - 1)) {
			case -1:
				strncpy(stext, strerror(errno), sizeof stext - 1);
				stext[sizeof stext - 1] = '\0';
				readin = False;
				break;
			case 0:
				strncpy(stext, "EOF", 4);
				readin = False;
				break;
			default:
				for(stext[r] = '\0', p = stext + strlen(stext) - 1; p >= stext && *p == '\n'; *p-- = '\0');
				for(; p >= stext && *p != '\n'; --p);
				if(p > stext)
					strncpy(stext, p + 1, sizeof stext);
			}
			drawstatus();
		}
		while(XPending(dpy)) {
			XNextEvent(dpy, &ev);
			if(handler[ev.type])
				(handler[ev.type])(&ev); /* call handler */
		}
	}
	cleanup();
	XCloseDisplay(dpy);
	return 0;
}