gping.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

			m->unreachable++;
	}
	m->seq++;
}

void
pingrcv(void *arg)
{
	uchar buf[512];
	Icmp *ip;
	ushort x;
	int i, n, fd;
	vlong now;
	Machine *m = arg;

	ip = (Icmp*)buf;
	fd = dup(m->pingfd, -1);
	for(;;){
		n = read(fd, buf, sizeof(buf));
		now = nsec();
		if(n <= 0)
			continue;
		if(n < MSGLEN){
			print("bad len %d/%d\n", n, MSGLEN);
			continue;
		}
		for(i = 32; i < MSGLEN; i++)
			if(buf[i] != (i&0xff))
				continue;
		x = (ip->seq[1]<<8)|ip->seq[0];
		if(ip->type != EchoReply || ip->code != 0)
			continue;
		lock(m);
		pingclean(m, x, now, ip->ttl);
		unlock(m);
	}
}

void
initmach(Machine *m, char *name)
{
	char *p;

	srand(time(0));
	p = strchr(name, '!');
	if(p){
		p++;
		m->name = estrdup(p+1);
	}else
		p = name;

	m->name = estrdup(p);
	m->nproc = 1;
	m->pingfd = dial(netmkaddr(m->name, "icmp", "1"), 0, 0, 0);
	if(m->pingfd < 0)
		sysfatal("dialing %s: %r", m->name);
	startproc(pingrcv, m);
}

ulong
rttscale(ulong x)
{
	if(x == 0)
		return 0;
	x = 10.0*log10(x) - 20.0;
	if(x < 0)
		x = 0;
	return x;
}

ulong
rttunscale(ulong x)
{
	double dx;

	x += 20;
	dx = x;
	return pow(10.0, dx/10.0);
}

void
rttval(Machine *m, long *v, long *vmax, long *mark)
{
	ulong x;

	if(m->rttmsgs == 0){
		x = m->lastrtt;
	} else {
		x = m->rttsum/m->rttmsgs;
		m->rttsum = m->rttmsgs = 0;
		m->lastrtt = x;
	}

	*v = rttscale(x);
	*vmax = Rttmax;
	*mark = 0;
}

void
lostval(Machine *m, long *v, long *vmax, long *mark)
{
	ulong x;

	if(m->rcvdmsgs+m->lostmsgs > 0)
		x = (m->lostavg>>1) + (((m->lostmsgs*100)/(m->lostmsgs + m->rcvdmsgs))>>1);
	else
		x = m->lostavg;
	m->lostavg = x;
	m->lostmsgs = m->rcvdmsgs = 0;

	if(m->unreachable){
		m->unreachable = 0;
		*mark = 100;
	} else
		*mark = 0;

	*v = x;
	*vmax = 100;
}

jmp_buf catchalarm;

void
alarmed(void *a, char *s)
{
	if(strcmp(s, "alarm") == 0)
		notejmp(a, catchalarm, 1);
	noted(NDFLT);
}

void
usage(void)
{
	fprint(2, "usage: %s machine [machine...]\n", argv0);
	exits("usage");
}

void
addgraph(int n)
{
	Graph *g, *ograph;
	int i, j;
	static int nadd;

	if(n > nelem(menu2str))
		abort();
	/* avoid two adjacent graphs of same color */
	if(ngraph>0 && graph[ngraph-1].colindex==nadd%Ncolor)
		nadd++;
	ograph = graph;
	graph = emalloc(nmach*(ngraph+1)*sizeof(Graph));
	for(i=0; i<nmach; i++)
		for(j=0; j<ngraph; j++)
			graph[i*(ngraph+1)+j] = ograph[i*ngraph+j];
	free(ograph);
	ngraph++;
	for(i=0; i<nmach; i++){
		g = &graph[i*ngraph+(ngraph-1)];
		memset(g, 0, sizeof(Graph));
		g->label = menu2str[n]+Opwid;
		g->newvalue = newvaluefn[n];
		g->update = update1;	/* no other update functions yet */
		g->mach = &mach[i];
		g->colindex = nadd%Ncolor;
	}
	present[n] = 1;
	nadd++;
}

int
which2index(int which)
{
	int i, n;

	n = -1;
	for(i=0; i<ngraph; i++){
		if(strcmp(menu2str[which]+Opwid, graph[i].label) == 0){
			n = i;
			break;
		}
	}
	if(n < 0){
		fprint(2, "%s: internal error can't drop graph\n", argv0);
		killall("error");
	}
	return n;
}

int
index2which(int index)
{
	int i, n;

	n = -1;
	for(i=0; i<Nmenu2; i++){
		if(strcmp(menu2str[i]+Opwid, graph[index].label) == 0){
			n = i;
			break;
		}
	}
	if(n < 0){
		fprint(2, "%s: internal error can't identify graph\n", argv0);
		killall("error");
	}
	return n;
}

void
dropgraph(int which)
{
	Graph *ograph;
	int i, j, n;

	if(which > nelem(menu2str))
		abort();
	/* convert n to index in graph table */
	n = which2index(which);
	ograph = graph;
	graph = emalloc(nmach*(ngraph-1)*sizeof(Graph));
	for(i=0; i<nmach; i++){
		for(j=0; j<n; j++)
			graph[i*(ngraph-1)+j] = ograph[i*ngraph+j];
		free(ograph[i*ngraph+j].data);
		freeimage(ograph[i*ngraph+j].overtmp);
		for(j++; j<ngraph; j++)
			graph[i*(ngraph-1)+j-1] = ograph[i*ngraph+j];
	}
	free(ograph);
	ngraph--;
	present[which] = 0;
}

void
addmachine(char *name)
{
	if(ngraph > 0){
		fprint(2, "%s: internal error: ngraph>0 in addmachine()\n", argv0);
		usage();
	}
	if(nmach == NMACH)
		sysfatal("too many machines");
	initmach(&mach[nmach++], name);
}


void
resize(void)
{
	int i, j, n, startx, starty, x, y, dx, dy, hashdx, ondata;
	Graph *g;
	Rectangle machr, r;
	long v, vmax, mark;
	char buf[128];

	draw(screen, screen->r, display->white, nil, ZP);

	/* label left edge */
	x = screen->r.min.x;
	y = screen->r.min.y + Labspace+mediumfont->height+Labspace;
	dy = (screen->r.max.y - y)/ngraph;
	dx = Labspace+stringwidth(mediumfont, "0")+Labspace;
	startx = x+dx+1;
	starty = y;
	for(i=0; i<ngraph; i++,y+=dy){
		draw(screen, Rect(x, y-1, screen->r.max.x, y), display->black, nil, ZP);
		draw(screen, Rect(x, y, x+dx, screen->r.max.y), cols[graph[i].colindex][0], nil, paritypt(x));
		label(Pt(x, y), dy, graph[i].label);
		draw(screen, Rect(x+dx, y, x+dx+1, screen->r.max.y), cols[graph[i].colindex][2], nil, ZP);
	}

	/* label right edge */
	dx = Labspace+stringwidth(mediumfont, "0.001")+Labspace;
	hashdx = dx;
	x = screen->r.max.x - dx;
	y = screen->r.min.y + Labspace+mediumfont->height+Labspace;
	for(i=0; i<ngraph; i++,y+=dy){
		draw(screen, Rect(x, y-1, screen->r.max.x, y), display->black, nil, ZP);
		draw(screen, Rect(x, y, x+dx, screen->r.max.y), cols[graph[i].colindex][0], nil, paritypt(x));
		hashmarks(Pt(x, y), dy, i);
		draw(screen, Rect(x+dx, y, x+dx+1, screen->r.max.y), cols[graph[i].colindex][2], nil, ZP);
	}

	/* label top edge */
	dx = (screen->r.max.x - dx - startx)/nmach;
	for(x=startx, i=0; i<nmach; i++,x+=dx){
		draw(screen, Rect(x-1, starty-1, x, screen->r.max.y), display->black, nil, ZP);
		j = dx/stringwidth(mediumfont, "0");
		n = mach[i].nproc;
		if(n>1 && j>=1+3+(n>10)+(n>100)){	/* first char of name + (n) */
			j -= 3+(n>10)+(n>100);
			if(j <= 0)
				j = 1;
			snprint(buf, sizeof buf, "%.*s(%d)", j, mach[i].name, n);
		}else
			snprint(buf, sizeof buf, "%.*s", j, mach[i].name);
		string(screen, Pt(x+Labspace, screen->r.min.y + Labspace), display->black, ZP,
			mediumfont, buf);
	}
	/* draw last vertical line */
	draw(screen,
		Rect(screen->r.max.x-hashdx-1, starty-1, screen->r.max.x-hashdx, screen->r.max.y),
		display->black, nil, ZP);

	/* create graphs */
	for(i=0; i<nmach; i++){
		machr = Rect(startx+i*dx, starty, screen->r.max.x, screen->r.max.y);
		if(i < nmach-1)
			machr.max.x = startx+(i+1)*dx - 1;
		else
			machr.max.x = screen->r.max.x - hashdx - 1;
		y = starty;
		for(j=0; j<ngraph; j++, y+=dy){
			g = &graph[i*ngraph+j];
			/* allocate data */
			ondata = g->ndata;
			g->ndata = Dx(machr)+1;	/* may be too many if label will be drawn here; so what? */
			g->data = erealloc(g->data, g->ndata*sizeof(long));
			if(g->ndata > ondata)
				memset(g->data+ondata, 0, (g->ndata-ondata)*sizeof(long));
			/* set geometry */
			g->r = machr;
			g->r.min.y = y;
			g->r.max.y = y+dy - 1;
			if(j == ngraph-1)
				g->r.max.y = screen->r.max.y;
			draw(screen, g->r, cols[g->colindex][0], nil, paritypt(g->r.min.x));
			g->overflow = 0;
			*g->msg = 0;
			freeimage(g->overtmp);
			g->overtmp = nil;
			g->overtmplen = 0;
			r = g->r;
			r.max.y = r.min.y+mediumfont->height;
			n = (g->r.max.x - r.min.x)/stringwidth(mediumfont, "9");
			if(n > 4){
				if(n > Gmsglen)
					n = Gmsglen;
				r.max.x = r.min.x+stringwidth(mediumfont, "9")*n;
				g->overtmplen = n;
				g->overtmp = allocimage(display, r, screen->chan, 0, -1);
			}
			g->newvalue(g->mach, &v, &vmax, &mark);
			redraw(g, vmax);
		}
	}

	flushimage(display, 1);
}

void
eresized(int new)
{
	lockdisplay(display);
	if(new && getwindow(display, Refnone) < 0) {
		fprint(2, "%s: can't reattach to window\n", argv0);
		killall("reattach");
	}
	resize();
	unlockdisplay(display);
}

void
dobutton2(Mouse *m)
{
	int i;

	for(i=0; i<Nmenu2; i++)
		if(present[i])
			memmove(menu2str[i], "drop ", Opwid);
		else
			memmove(menu2str[i], "add  ", Opwid);
	i = emenuhit(3, m, &menu2);
	if(i >= 0){
		if(!present[i])
			addgraph(i);
		else if(ngraph > 1)
			dropgraph(i);
		resize();
	}
}

void
dobutton1(Mouse *m)
{
	int i, n, dx, dt;
	Graph *g;
	char *e;
	double f;

	for(i = 0; i < ngraph*nmach; i++){
		if(ptinrect(m->xy, graph[i].r))
			break;
	}
	if(i == ngraph*nmach)
		return;

	g = &graph[i];
	if(g->overtmp == nil)
		return;

	// clear any previous message and cursor
	if(g->overflow || *g->msg){
		clearmsg(g);
		*g->msg = 0;
		clearcursor(g);
	}

	dx = g->r.max.x - m->xy.x;
	g->cursor = dx;
	dt = dx*pinginterval;
	e = &g->msg[sizeof(g->msg)];
	seprint(g->msg, e, "%s", ctime(starttime-dt/1000)+11);
	g->msg[8] = 0;
	n = 8;

	switch(index2which(i)){
	case Mrtt:
		f = rttunscale(g->data[dx]);
		seprint(g->msg+n, e, " %3.3g", f/1000000);
		break;
	case Mlost:
		seprint(g->msg+n, e, " %d%%", g->data[dx]);
		break;
	}

	drawmsg(g, g->msg);
	drawcursor(g, m->xy.x);
}

void
mouseproc(void*)
{
	Mouse mouse;

	for(;;){
		mouse = emouse();
		if(mouse.buttons == 4){
			lockdisplay(display);
			dobutton2(&mouse);
			unlockdisplay(display);
		} else if(mouse.buttons == 1){
			lockdisplay(display);
			dobutton1(&mouse);
			unlockdisplay(display);
		}
	}
}

void
startproc(void (*f)(void*), void *arg)
{
	int pid;

	switch(pid = rfork(RFPROC|RFMEM|RFNOWAIT)){
	case -1:
		fprint(2, "%s: fork failed: %r\n", argv0);
		killall("fork failed");
	case 0:
		f(arg);
		killall("process died");
		exits(nil);
	}
	pids[npid++] = pid;
}

void
main(int argc, char *argv[])
{
	int i, j;
	long v, vmax, mark;
	char flags[10], *f, *p;

	fmtinstall('V', eipfmt);

	f = flags;
	pinginterval = 5000;		// 5 seconds
	ARGBEGIN{
	case 'i':
		p = ARGF();
		if(p == nil)
			usage();
		pinginterval = atoi(p);
		break;
	default:
		if(f - flags >= sizeof(flags)-1)
			usage();
		*f++ = ARGC();
		break;
	}ARGEND
	*f = 0;

	for(i=0; i<argc; i++)
		addmachine(argv[i]);

	for(f = flags; *f; f++)
		switch(*f){
		case 'l':
			addgraph(Mlost);
			break;
		case 'r':
			addgraph(Mrtt);
			break;
		}

	if(nmach == 0)
		usage();

	if(ngraph == 0)
		addgraph(Mrtt);

	for(i=0; i<nmach; i++)
		for(j=0; j<ngraph; j++)
			graph[i*ngraph+j].mach = &mach[i];

	if(initdraw(nil, nil, argv0) < 0){
		fprint(2, "%s: initdraw failed: %r\n", argv0);
		exits("initdraw");
	}
	colinit();
	einit(Emouse);
	notify(nil);
	startproc(mouseproc, 0);
	display->locking = 1;	/* tell library we're using the display lock */

	resize();

	starttime = time(0);

	unlockdisplay(display); /* display is still locked from initdraw() */
	for(j = 0; ; j++){
		lockdisplay(display);
		if(j == nmach){
			parity = 1-parity;
			j = 0;
			for(i=0; i<nmach*ngraph; i++){
				graph[i].newvalue(graph[i].mach, &v, &vmax, &mark);
				graph[i].update(&graph[i], v, vmax, mark);
			}
			starttime = time(0);
		}
		flushimage(display, 1);
		unlockdisplay(display);
		pingsend(&mach[j%nmach]);
		sleep(pinginterval/nmach);
	}
}