devsd.c

在x86平台上运行不可信任代码的sandbox。

		return n;

	case Qtopdir:
	case Qunitdir:
		return devdirread(c, a, n, 0, 0, sdgen);

	case Qctl:
		sdev = sdgetdev(DEV(c->qid));
		if(sdev == nil)
			error(Enonexist);

		unit = sdev->unit[UNIT(c->qid)];
		m = 16*1024;	/* room for register dumps */
		p = malloc(m);
		l = snprint(p, m, "inquiry %.48s\n",
			(char*)unit->inquiry+8);
		qlock(&unit->ctl);
		/*
		 * If there's a device specific routine it must
		 * provide all information pertaining to night geometry
		 * and the garscadden trains.
		 */
		if(unit->dev->ifc->rctl)
			l += unit->dev->ifc->rctl(unit, p+l, m-l);
		if(unit->sectors == 0)
			sdinitpart(unit);
		if(unit->sectors){
			if(unit->dev->ifc->rctl == nil)
				l += snprint(p+l, m-l,
					"geometry %llud %lud\n",
					unit->sectors, unit->secsize);
			pp = unit->part;
			for(i = 0; i < unit->npart; i++){
				if(pp->valid)
					l += snprint(p+l, m-l,
						"part %s %llud %llud\n",
						pp->perm.name, pp->start, pp->end);
				pp++;
			}
		}
		qunlock(&unit->ctl);
		decref(&sdev->r);
		l = readstr(offset, a, n, p);
		free(p);
		return l;

	case Qraw:
		sdev = sdgetdev(DEV(c->qid));
		if(sdev == nil)
			error(Enonexist);

		unit = sdev->unit[UNIT(c->qid)];
		qlock(&unit->raw);
		if(waserror()){
			qunlock(&unit->raw);
			decref(&sdev->r);
			nexterror();
		}
		if(unit->state == Rawdata){
			unit->state = Rawstatus;
			i = sdrio(unit->req, a, n);
		}
		else if(unit->state == Rawstatus){
			status = unit->req->status;
			unit->state = Rawcmd;
			free(unit->req);
			unit->req = nil;
			i = readnum(0, a, n, status, NUMSIZE);
		} else
			i = 0;
		qunlock(&unit->raw);
		decref(&sdev->r);
		poperror();
		return i;

	case Qpart:
		return sdbio(c, 0, a, n, off);
	}
}

static void legacytopctl(Cmdbuf*);

static long
sdwrite(Chan* c, void* a, long n, vlong off)
{
	char *f0;
	int i;
	uvlong end, start;
	Cmdbuf *cb;
	SDifc *ifc;
	SDreq *req;
	SDunit *unit;
	SDev *sdev;

	switch(TYPE(c->qid)){
	default:
		error(Eperm);
	case Qtopctl:
		cb = parsecmd(a, n);
		if(waserror()){
			free(cb);
			nexterror();
		}
		if(cb->nf == 0)
			error("empty control message");
		f0 = cb->f[0];
		cb->f++;
		cb->nf--;
		if(strcmp(f0, "config") == 0){
			/* wormhole into ugly legacy interface */
			legacytopctl(cb);
			poperror();
			free(cb);
			break;
		}
		/*
		 * "ata arg..." invokes sdifc[i]->wtopctl(nil, cb),
		 * where sdifc[i]->name=="ata" and cb contains the args.
		 */
		ifc = nil;
		sdev = nil;
		for(i=0; sdifc[i]; i++){
			if(strcmp(sdifc[i]->name, f0) == 0){
				ifc = sdifc[i];
				sdev = nil;
				goto subtopctl;
			}
		}
		/*
		 * "sd1 arg..." invokes sdifc[i]->wtopctl(sdev, cb),
		 * where sdifc[i] and sdev match controller letter "1",
		 * and cb contains the args.
		 */
		if(f0[0]=='s' && f0[1]=='d' && f0[2] && f0[3] == 0){
			if((sdev = sdgetdev(f0[2])) != nil){
				ifc = sdev->ifc;
				goto subtopctl;
			}
		}
		error("unknown interface");

	subtopctl:
		if(waserror()){
			if(sdev)
				decref(&sdev->r);
			nexterror();
		}
		if(ifc->wtopctl)
			ifc->wtopctl(sdev, cb);
		else
			error(Ebadctl);
		poperror();
		poperror();
		if (sdev)
			decref(&sdev->r);
		free(cb);
		break;

	case Qctl:
		cb = parsecmd(a, n);
		sdev = sdgetdev(DEV(c->qid));
		if(sdev == nil)
			error(Enonexist);
		unit = sdev->unit[UNIT(c->qid)];

		qlock(&unit->ctl);
		if(waserror()){
			qunlock(&unit->ctl);
			decref(&sdev->r);
			free(cb);
			nexterror();
		}
		if(unit->vers != c->qid.vers)
			error(Echange);

		if(cb->nf < 1)
			error(Ebadctl);
		if(strcmp(cb->f[0], "part") == 0){
			if(cb->nf != 4)
				error(Ebadctl);
			if(unit->sectors == 0 && !sdinitpart(unit))
				error(Eio);
			start = strtoull(cb->f[2], 0, 0);
			end = strtoull(cb->f[3], 0, 0);
			sdaddpart(unit, cb->f[1], start, end);
		}
		else if(strcmp(cb->f[0], "delpart") == 0){
			if(cb->nf != 2 || unit->part == nil)
				error(Ebadctl);
			sddelpart(unit, cb->f[1]);
		}
		else if(unit->dev->ifc->wctl)
			unit->dev->ifc->wctl(unit, cb);
		else
			error(Ebadctl);
		qunlock(&unit->ctl);
		decref(&sdev->r);
		poperror();
		free(cb);
		break;

	case Qraw:
		sdev = sdgetdev(DEV(c->qid));
		if(sdev == nil)
			error(Enonexist);
		unit = sdev->unit[UNIT(c->qid)];
		qlock(&unit->raw);
		if(waserror()){
			qunlock(&unit->raw);
			decref(&sdev->r);
			nexterror();
		}
		switch(unit->state){
		case Rawcmd:
			if(n < 6 || n > sizeof(req->cmd))
				error(Ebadarg);
			if((req = malloc(sizeof(SDreq))) == nil)
				error(Enomem);
			req->unit = unit;
			memmove(req->cmd, a, n);
			req->clen = n;
			req->flags = SDnosense;
			req->status = ~0;

			unit->req = req;
			unit->state = Rawdata;
			break;

		case Rawstatus:
			unit->state = Rawcmd;
			free(unit->req);
			unit->req = nil;
			error(Ebadusefd);

		case Rawdata:
			unit->state = Rawstatus;
			unit->req->write = 1;
			n = sdrio(unit->req, a, n);
		}
		qunlock(&unit->raw);
		decref(&sdev->r);
		poperror();
		break;
	case Qpart:
		return sdbio(c, 1, a, n, off);
	}

	return n;
}

static int
sdwstat(Chan* c, uchar* dp, int n)
{
	Dir *d;
	SDpart *pp;
	SDperm *perm;
	SDunit *unit;
	SDev *sdev;

	if(c->qid.type & QTDIR)
		error(Eperm);

	sdev = sdgetdev(DEV(c->qid));
	if(sdev == nil)
		error(Enonexist);
	unit = sdev->unit[UNIT(c->qid)];
	qlock(&unit->ctl);
	d = nil;
	if(waserror()){
		free(d);
		qunlock(&unit->ctl);
		decref(&sdev->r);
		nexterror();
	}

	switch(TYPE(c->qid)){
	default:
		error(Eperm);
	case Qctl:
		perm = &unit->ctlperm;
		break;
	case Qraw:
		perm = &unit->rawperm;
		break;
	case Qpart:
		pp = &unit->part[PART(c->qid)];
		if(unit->vers+pp->vers != c->qid.vers)
			error(Enonexist);
		perm = &pp->perm;
		break;
	}

	if(strcmp(up->user, perm->user) && !iseve())
		error(Eperm);

	d = smalloc(sizeof(Dir)+n);
	n = convM2D(dp, n, &d[0], (char*)&d[1]);
	if(n == 0)
		error(Eshortstat);
	if(!emptystr(d[0].uid))
		kstrdup(&perm->user, d[0].uid);
	if(d[0].mode != ~0UL)
		perm->perm = (perm->perm & ~0777) | (d[0].mode & 0777);

	free(d);
	qunlock(&unit->ctl);
	decref(&sdev->r);
	poperror();
	return n;
}

static int
configure(char* spec, DevConf* cf)
{
	SDev *s, *sdev;
	char *p;
	int i;

	if(sdindex(*spec) < 0)
		error("bad sd spec");

	if((p = strchr(cf->type, '/')) != nil)
		*p++ = '\0';

	for(i = 0; sdifc[i] != nil; i++)
		if(strcmp(sdifc[i]->name, cf->type) == 0)
			break;
	if(sdifc[i] == nil)
		error("sd type not found");
	if(p)
		*(p-1) = '/';

	if(sdifc[i]->probe == nil)
		error("sd type cannot probe");

	sdev = sdifc[i]->probe(cf);
	for(s=sdev; s; s=s->next)
		s->idno = *spec;
	sdadddevs(sdev);
	return 0;
}

static int
unconfigure(char* spec)
{
	int i;
	SDev *sdev;
	SDunit *unit;

	if((i = sdindex(*spec)) < 0)
		error(Enonexist);

	qlock(&devslock);
	if((sdev = devs[i]) == nil){
		qunlock(&devslock);
		error(Enonexist);
	}
	if(sdev->r.ref){
		qunlock(&devslock);
		error(Einuse);
	}
	devs[i] = nil;
	qunlock(&devslock);

	/* make sure no interrupts arrive anymore before removing resources */
	if(sdev->enabled && sdev->ifc->disable)
		sdev->ifc->disable(sdev);

	for(i = 0; i != sdev->nunit; i++){
		if((unit = sdev->unit[i])){
			free(unit->perm.name);
			free(unit->perm.user);
			free(unit);
		}
	}

	if(sdev->ifc->clear)
		sdev->ifc->clear(sdev);
	free(sdev);
	return 0;
}

static int
sdconfig(int on, char* spec, DevConf* cf)
{
	if(on)
		return configure(spec, cf);
	return unconfigure(spec);
}

Dev sddevtab = {
	'S',
	"sd",

	sdreset,
	devinit,
	devshutdown,
	sdattach,
	sdwalk,
	sdstat,
	sdopen,
	devcreate,
	sdclose,
	sdread,
	devbread,
	sdwrite,
	devbwrite,
	devremove,
	sdwstat,
	devpower,
	sdconfig,
};

/*
 * This is wrong for so many reasons.  This code must go.
 */
typedef struct Confdata Confdata;
struct Confdata {
	int	on;
	char*	spec;
	DevConf	cf;
};

static void
parseswitch(Confdata* cd, char* option)
{
	if(!strcmp("on", option))
		cd->on = 1;
	else if(!strcmp("off", option))
		cd->on = 0;
	else
		error(Ebadarg);
}

static void
parsespec(Confdata* cd, char* option)
{
	if(strlen(option) > 1)
		error(Ebadarg);
	cd->spec = option;
}

static Devport*
getnewport(DevConf* dc)
{
	Devport *p;

	p = (Devport *)malloc((dc->nports + 1) * sizeof(Devport));
	if(dc->nports > 0){
		memmove(p, dc->ports, dc->nports * sizeof(Devport));
		free(dc->ports);
	}
	dc->ports = p;
	p = &dc->ports[dc->nports++];
	p->size = -1;
	p->port = (ulong)-1;
	return p;
}

static void
parseport(Confdata* cd, char* option)
{
	char *e;
	Devport *p;

	if(cd->cf.nports == 0 || cd->cf.ports[cd->cf.nports-1].port != (ulong)-1)
		p = getnewport(&cd->cf);
	else
		p = &cd->cf.ports[cd->cf.nports-1];
	p->port = strtol(option, &e, 0);
	if(e == nil || *e != '\0')
		error(Ebadarg);
}

static void
parsesize(Confdata* cd, char* option)
{
	char *e;
	Devport *p;

	if(cd->cf.nports == 0 || cd->cf.ports[cd->cf.nports-1].size != -1)
		p = getnewport(&cd->cf);
	else
		p = &cd->cf.ports[cd->cf.nports-1];
	p->size = (int)strtol(option, &e, 0);
	if(e == nil || *e != '\0')
		error(Ebadarg);
}

static void
parseirq(Confdata* cd, char* option)
{
	char *e;

	cd->cf.intnum = strtoul(option, &e, 0);
	if(e == nil || *e != '\0')
		error(Ebadarg);
}

static void
parsetype(Confdata* cd, char* option)
{
	cd->cf.type = option;
}

static struct {
	char	*name;
	void	(*parse)(Confdata*, char*);
} options[] = {
	"switch",	parseswitch,
	"spec",		parsespec,
	"port",		parseport,
	"size",		parsesize,
	"irq",		parseirq,
	"type",		parsetype,
};

static void
legacytopctl(Cmdbuf *cb)
{
	char *opt;
	int i, j;
	Confdata cd;

	memset(&cd, 0, sizeof cd);
	cd.on = -1;
	for(i=0; i<cb->nf; i+=2){
		if(i+2 > cb->nf)
			error(Ebadarg);
		opt = cb->f[i];
		for(j=0; j<nelem(options); j++)
			if(strcmp(opt, options[j].name) == 0){
				options[j].parse(&cd, cb->f[i+1]);
				break;
			}
		if(j == nelem(options))
			error(Ebadarg);
	}
	/* this has been rewritten to accomodate sdaoe */
	if(cd.on < 0 || cd.spec == 0)
		error(Ebadarg);
	if(cd.on && cd.cf.type == nil)
		error(Ebadarg);
	sdconfig(cd.on, cd.spec, &cd.cf);
}