/* * sd loopback driver, * copyright © 2009-10 erik quanstrom */ #include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h"#include "../port/error.h"#include "../port/sd.h"#include "../port/netif.h" extern	char	Echange[];extern	char	Enotup[]; #define uprint(...)	snprint(up->genbuf, sizeof up->genbuf, __VA_ARGS__); enum {	Maxpath		= 256,	Devsectsize	= 512,}; typedef struct Ctlr Ctlr;struct Ctlr {	QLock; 	Ctlr	*next;	SDunit	*unit; 	char	path[Maxpath];	Chan	*c; 	uint	vers;	uchar	drivechange; 	uvlong	fixedsectors;	uvlong	sectors;	uint	sectsize;}; static	Lock	ctlrlock;static	Ctlr	*head;static	Ctlr	*tail; SDifc sdloopifc; /* must call with c qlocked */static voididentify(Ctlr *c, SDunit *u){	int n;	uvlong s, osectors;	uchar buf[sizeof(Dir) + 100];	Dir dir; 	if(waserror()){		iprint("sdloop: identify: %s\n", up->errstr);		nexterror();	}	osectors = c->sectors;	n = devtab[c->c->type]->stat(c->c, buf, sizeof buf);	if(convM2D(buf, n, &dir, nil) == 0)		error("internal error: stat error in seek");	s = dir.length / c->sectsize;	poperror(); 	memset(u->inquiry, 0, sizeof u->inquiry);	u->inquiry[2] = 2;	u->inquiry[3] = 2;	u->inquiry[4] = sizeof u->inquiry - 4;	memmove(u->inquiry+8, c->path, 40); 	if(osectors == 0 || osectors != s){		if(c->fixedsectors != 0)			c->sectors = c->fixedsectors;		else			c->sectors = s;		c->drivechange = 1;		c->vers++;	}} static Ctlr*ctlrlookup(char *path){	Ctlr *c; 	lock(&ctlrlock);	for(c = head; c; c = c->next)		if(strcmp(c->path, path) == 0)			break;	unlock(&ctlrlock);	return c;} static Ctlr*newctlr(char *path){	Ctlr *c; 	if(ctlrlookup(path))		error(Eexist);	if((c = malloc(sizeof *c)) == nil)		error(Enomem);	if(waserror()){		free(c);		nexterror();	}	c->c = namec(path, Aopen, ORDWR, 0);	poperror();	kstrcpy(c->path, path, sizeof c->path);	lock(&ctlrlock);	if(head != nil)		tail->next = c;	else		head = c;	tail = c;	unlock(&ctlrlock);	return c;} static voiddelctlr(Ctlr *c){	Ctlr *x, *prev; 	lock(&ctlrlock); 	for(prev = nil, x = head; x; prev = x, x = c->next)		if(strcmp(c->path, x->path) == 0)			break;	if(x == nil){		unlock(&ctlrlock);		error(Enonexist);	} 	if(prev)		prev->next = x->next;	else		head = x->next;	if(x->next == nil)		tail = prev;	unlock(&ctlrlock); 	if(x->c)		cclose(x->c);	free(x);} static SDev*probe(char *path, SDev *s){	char *p, *q;	uint sectsize;	uvlong sectors;	Ctlr *c; 	sectsize = 0;	sectors = 0;	if(p = strchr(path, '!')){		*p++ = 0;		if((q = strchr(p, '!')) != nil){			sectors = strtoull(p, nil, 0);			p = q + 1;		}		sectsize = strtoul(p, nil, 0);	}	c = newctlr(path);	c->sectsize = sectsize? sectsize: Devsectsize;	c->fixedsectors = sectors;	if(s == nil && (s = malloc(sizeof *s)) == nil)		return nil;	s->ctlr = c;	s->ifc = &sdloopifc;	s->nunit = 1;	return s;} static char 	*probef[32];static int 	nprobe; static intpnpprobeid(char *s){	int id; 	if(strlen(s) < 2)		return 0;	id = 'l';	if(s[1] == '!')		id = s[0];	return id;} static SDev*pnp(void){	int i, id;	char *p;	SDev *h, *t, *s; 	if((p = getconf("loopdev")) == 0)		return nil;	nprobe = tokenize(p, probef, nelem(probef));	h = t = 0;	for(i = 0; i < nprobe; i++){		id = pnpprobeid(probef[i]);		if(id == 0)			continue;		s = malloc(sizeof *s);		if(s == nil)			break;		s->ctlr = 0;		s->idno = id;		s->ifc = &sdloopifc;		s->nunit = 1; 		if(h)			t->next = s;		else			h = s;		t = s;	}	return h;} static Ctlr*pnpprobe(SDev *s){	char *p;	static int i; 	if(i > nprobe)		return nil;	p = probef[i++];	if(strlen(p) < 2)		return nil;	if(p[1] == '!')		p += 2;	return probe(p, s)->ctlr;}  static intloopverify(SDunit *u){	SDev *s;	Ctlr *c; 	s = u->dev;	c = s->ctlr;	if(c == nil){		if(waserror())			return 0;		s->ctlr = c = pnpprobe(s);		poperror();	}	c->drivechange = 1;	return 1;} static intconnect(SDunit *u, Ctlr *c){	qlock(c);	if(waserror()){		qunlock(c);		return -1;	}	identify(u->dev->ctlr, u);	qunlock(c);	poperror();	return 0;} static intlooponline(SDunit *u){	Ctlr *c;	int r; 	c = u->dev->ctlr;	if(c->drivechange){		if(connect(u, c) == -1)			return 0;		r = 2;		c->drivechange = 0;		u->sectors = c->sectors;		u->secsize = c->sectsize;	} else		r = 1;	return r;} static longloopbio(SDunit *u, int, int write, void *a, long count, uvlong lba){	uchar *data;	int n;	long (*rio)(Chan*, void*, long, vlong);	Ctlr *c; 	c = u->dev->ctlr;	data = a;	if(write)		rio = devtab[c->c->type]->write;	else		rio = devtab[c->c->type]->read; 	if(waserror()){		if(strcmp(up->errstr, Echange) == 0 ||		    strcmp(up->errstr, Enotup) == 0)			u->sectors = 0;		nexterror();	}	n = rio(c->c, data, c->sectsize * count, c->sectsize * lba);	poperror();	return n;} static intlooprio(SDreq *r){	int i, count, rw;	uvlong lba;	SDunit *u; 	u = r->unit; 	if(r->cmd[0] == 0x35 || r->cmd[0] == 0x91)		return sdsetsense(r, SDok, 0, 0, 0); 	if((i = sdfakescsi(r)) != SDnostatus)		return r->status = i;	if((i = sdfakescsirw(r, &lba, &count, &rw)) != SDnostatus)		return i;	r->rlen = loopbio(u, r->lun, rw == SDwrite, r->data, count, lba);	return r->status = SDok;} static intlooprctl(SDunit *u, char *p, int l){	Ctlr *c;	char *e, *op; 	if((c = u->dev->ctlr) == nil)		return 0;	e = p+l;	op = p; 	p = seprint(p, e, "path\t%s\n", c->path);	p = seprint(p, e, "geometry %llud %d\n", c->sectors, c->sectsize);	return p - op;} static intloopwctl(SDunit *, Cmdbuf *cmd){	cmderror(cmd, Ebadarg);	return 0;} static SDev*loopprobew(DevConf *c){	char *p; 	p = strchr(c->type, '/');	if(p == nil || strlen(p) > Maxpath - 1)		error(Ebadarg);	p++;	if(ctlrlookup(p))		error(Einuse);	return probe(p, nil);} static voidloopclear(SDev *s){	delctlr((Ctlr *)s->ctlr);} static char*looprtopctl(SDev *s, char *p, char *e){	Ctlr *c; 	c = s->ctlr;	return seprint(p, e, "%s loop %s\n", s->name, c? c->path: "");} static intloopwtopctl(SDev *, Cmdbuf *cmd){	switch(cmd->nf){	default:		cmderror(cmd, Ebadarg);	}	return 0;} SDifc sdloopifc = {	"loop", 	pnp,	nil,		/* legacy */	nil,		/* enable */	nil,		/* disable */ 	loopverify,	looponline,	looprio,	looprctl,	loopwctl, 	loopbio,	loopprobew,	/* probe */	loopclear,	/* clear */	looprtopctl,	loopwtopctl,};