scuzz.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

		}
		break;
	}
	total = 0;
	n = MIN(nbytes, maxiosize);
	if((n = readn(fd, rwbuf, n)) == -1){
		fprint(2, "file read failed %r\n");
		close(fd);
		return -1;
	}
	if((x = SRwtrack(rp, rwbuf, n, track, mode)) != n){
		fprint(2, "wtrack: write incomplete: asked %ld, did %ld\n", n, x);
		if(rp->status == STok)
			rp->status = Status_SW;
		close(fd);
		return -1;
	}
	nbytes -= n;
	total += n;
	while(nbytes){
		n = MIN(nbytes, maxiosize);
		if((n = read(fd, rwbuf, n)) == -1){
			break;
		}
		if((x = SRwrite(rp, rwbuf, n)) != n){
			fprint(2, "write: write incomplete: asked %ld, did %ld\n", n, x);
			if(rp->status == STok)
				rp->status = Status_SW;
			break;
		}
		nbytes -= n;
		total += n;
	}
	close(fd);
	if(pid >= 0 && waitfor(pid)){
		rp->status = Status_SW;
		return -1;
	}
	return total;
}

static long
cmdload(ScsiReq *rp, int argc, char *argv[])
{
	USED(argc, argv);
	return SRmload(rp, 0);
}

static long
cmdunload(ScsiReq *rp, int argc, char *argv[])
{
	USED(argc, argv);
	return SRmload(rp, 1);
}

static long
cmdfixation(ScsiReq *rp, int argc, char *argv[])
{
	uchar type;
	char *p;

	type = 0;
	if(argc && (type = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
		rp->status = Status_BADARG;
		return -1;
	}
	return SRfixation(rp, type);
}

static long
cmdeinit(ScsiReq *rp, int argc, char *argv[])
{
	USED(argc, argv);
	return SReinitialise(rp);
}

static long
cmdmmove(ScsiReq *rp, int argc, char *argv[])
{
	int transport, source, destination, invert;
	char *p;

	invert = 0;

	switch(argc){

	default:
		rp->status = Status_BADARG;
		return -1;

	case 4:
		if((invert = strtoul(argv[3], &p, 0)) == 0 && p == argv[3]){
			rp->status = Status_BADARG;
			return -1;
		}
		/*FALLTHROUGH*/

	case 3:
		if((transport = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		if((source = strtoul(argv[1], &p, 0)) == 0 && p == argv[1]){
			rp->status = Status_BADARG;
			return -1;
		}
		if((destination = strtoul(argv[2], &p, 0)) == 0 && p == argv[2]){
			rp->status = Status_BADARG;
			return -1;
		}
		break;
	}

	return SRmmove(rp, transport, source, destination, invert);
}

static long
cmdestatus(ScsiReq *rp, int argc, char *argv[])
{
	uchar *list, *lp, type;
	long d, i, n, nbytes, status;
	char *p;

	type = 0;
	nbytes = 4096;

	switch(argc){

	default:
		rp->status = Status_BADARG;
		return -1;

	case 2:
		if((nbytes = strtoul(argv[1], &p, 0)) == 0 && p == argv[1]){
			rp->status = Status_BADARG;
			return -1;
		}
		/*FALLTHROUGH*/

	case 1:
		if((type = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		break;

	case 0:
		break;
	}

	list = malloc(nbytes);
	if(list == 0){
		rp->status = STnomem;
		return -1;
	}
	status = SRestatus(rp, type, list, nbytes);
	if(status == -1){
		free(list);
		return -1;
	}

	lp = list;
	nbytes = ((lp[5]<<16)|(lp[6]<<8)|lp[7])-8;
	Bprint(&bout, " Header\n   ");
	for(i = 0; i < 8; i++){				/* header */
		Bprint(&bout, " %2.2uX", *lp);
		lp++;
	}
	Bputc(&bout, '\n');

	while(nbytes > 0){				/* pages */
		i = ((lp[5]<<16)|(lp[6]<<8)|lp[7]);
		nbytes -= i+8;
		Bprint(&bout, " Type");
		for(n = 0; n < 8; n++)			/* header */
			Bprint(&bout, " %2.2uX", lp[n]);
		Bprint(&bout, "\n   ");
		d = (lp[2]<<8)|lp[3];
		lp += 8;
		for(n = 0; n < i; n++){
			if(n && (n % d) == 0)
				Bprint(&bout, "\n   ");
			Bprint(&bout, " %2.2uX", *lp);
			lp++;
		}
		if(n && (n % d))
			Bputc(&bout, '\n');
	}

	free(list);
	return status;
}

static long
cmdhelp(ScsiReq *rp, int argc, char *argv[])
{
	ScsiCmd *cp;
	char *p;

	USED(rp);
	if(argc)
		p = argv[0];
	else
		p = 0;
	for(cp = scsicmd; cp->name; cp++){
		if(p == 0 || strcmp(p, cp->name) == 0)
			Bprint(&bout, "%s\n", cp->help);
	}
	return 0;
}

static int atatable[4] = {
	'C', 'D', 'E', 'F',
};
static int scsitable[16] = {
	'0', '1', '2', '3', '4', '5', '6', '7',
	'8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
};
static int unittable[16] = {
	'0', '1', '2', '3', '4', '5', '6', '7',
	'8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
};

static long
cmdprobe(ScsiReq *rp, int argc, char *argv[])
{
	char buf[32];
	ScsiReq scsireq;
	char *ctlr, *unit;

	USED(argc, argv);
	rp->status = STok;
	scsireq.flags = 0;

	for(ctlr="CDEF0123456789abcdef"; *ctlr; ctlr++) {
		/*
		 * I can guess how many units you have.
		 */
		if(*ctlr >= 'C' && *ctlr <= 'F')
			unit = "01";
		else if((*ctlr >= '0' && *ctlr <= '9')
		     || (*ctlr >= 'a' && *ctlr <= 'f'))
			unit = "0123456789abcdef";
		else
			unit = "012345678";

		for(; *unit; unit++){
			sprint(buf, "/dev/sd%c%c", *ctlr, *unit);
			if(SRopenraw(&scsireq, buf) == -1)
				/*
				return -1;
				 */
				continue;
			SRreqsense(&scsireq);
			switch(scsireq.status){

			default:
				break;

			case STok:
			case Status_SD:
				Bprint(&bout, "%s: ", buf);
				cmdinquiry(&scsireq, 0, 0);
				break;
			}
			SRclose(&scsireq);
		}
	}
	return 0;
}

static long
cmdclose(ScsiReq *rp, int argc, char *argv[])
{
	USED(argc, argv);
	return SRclose(rp);
}

static long
cmdopen(ScsiReq *rp, int argc, char *argv[])
{
	int raw;
	long status;

	raw = 0;
	if(argc && strcmp("-r", argv[0]) == 0){
		raw = 1;
		argc--, argv++;
	}
	if(argc != 1){
		rp->status = Status_BADARG;
		return -1;
	}
	if(raw == 0){
		if((status = SRopen(rp, argv[0])) != -1 && verbose)
			Bprint(&bout, "%sblock size: %ld\n",
				rp->flags&Fbfixed? "fixed ": "", rp->lbsize);
	}
	else {
		status = SRopenraw(rp, argv[0]);
		rp->lbsize = 512;
	}
	return status;
}

static ScsiCmd scsicmd[] = {
	{ "ready",	cmdready,	1,		/*[0x00]*/
	  "ready",
	},
	{ "rewind",	cmdrewind,	1,		/*[0x01]*/
	  "rewind",
	},
	{ "rezero",	cmdrewind,	1,		/*[0x01]*/
	  "rezero",
	},
	{ "reqsense",	cmdreqsense,	1,		/*[0x03]*/
	  "reqsense",
	},
	{ "format",	cmdformat,	0,		/*[0x04]*/
	  "format",
	},
	{ "rblimits",	cmdrblimits,	1,		/*[0x05]*/
	  "rblimits",
	},
	{ "read",	cmdread,	1,		/*[0x08]*/
	  "read [|]file [nbytes]",
	},
	{ "write",	cmdwrite,	1,		/*[0x0A]*/
	  "write [|]file [nbytes]",
	},
	{ "seek",	cmdseek,	1,		/*[0x0B]*/
	  "seek offset [whence]",
	},
	{ "filemark",	cmdfilemark,	1,		/*[0x10]*/
	  "filemark [howmany]",
	},
	{ "space",	cmdspace,	1,		/*[0x11]*/
	  "space [-f] [-b] [[--] howmany]",
	},
	{ "inquiry",	cmdinquiry,	1,		/*[0x12]*/
	  "inquiry",
	},
	{ "modeselect6",cmdmodeselect6,	1,		/*[0x15] */
	  "modeselect6 bytes...",
	},
	{ "modeselect",	cmdmodeselect10, 1,		/*[0x55] */
	  "modeselect bytes...",
	},
	{ "modesense6",	cmdmodesense6,	1,		/*[0x1A]*/
	  "modesense6 [page [nbytes]]",
	},
	{ "modesense",	cmdmodesense10, 1,		/*[0x5A]*/
	  "modesense [page [nbytes]]",
	},
	{ "start",	cmdstart,	1,		/*[0x1B]*/
	  "start [code]",
	},
	{ "stop",	cmdstop,	1,		/*[0x1B]*/
	  "stop",
	},
	{ "eject",	cmdeject,	1,		/*[0x1B]*/
	  "eject",
	},
	{ "ingest",	cmdingest,	1,		/*[0x1B]*/
	  "ingest",
	},
	{ "capacity",	cmdcapacity,	1,		/*[0x25]*/
	  "capacity",
	},

	{ "blank",	cmdblank,	1,		/*[0xA1]*/
	  "blank [track/LBA [type]]",
	},
//	{ "synccache",	cmdsynccache,	1,		/*[0x35]*/
//	  "synccache",
//	},
	{ "rtoc",	cmdrtoc,	1,		/*[0x43]*/
	  "rtoc [track/session-number [format]]",
	},
	{ "rdiscinfo",	cmdrdiscinfo,	1,		/*[0x51]*/
	  "rdiscinfo",
	},
	{ "rtrackinfo",	cmdrtrackinfo,	1,		/*[0x52]*/
	  "rtrackinfo [track]",
	},

	{ "cdpause",	cmdcdpause,	1,		/*[0x4B]*/
	  "cdpause",
	},
	{ "cdresume",	cmdcdresume,	1,		/*[0x4B]*/
	  "cdresume",
	},
	{ "cdstop",	cmdcdstop,	1,		/*[0x4E]*/
	  "cdstop",
	},
	{ "cdplay",	cmdcdplay,	1,		/*[0xA5]*/
	  "cdplay [track-number] or [-r [LBA [length]]]",
	},
	{ "cdload",	cmdcdload,	1,		/*[0xA6*/
	  "cdload [slot]",
	},
	{ "cdunload",	cmdcdunload,	1,		/*[0xA6]*/
	  "cdunload [slot]",
	},
	{ "cdstatus",	cmdcdstatus,	1,		/*[0xBD]*/
	  "cdstatus",
	},
//	{ "getconf",	cmdgetconf,	1,		/*[0x46]*/
//	  "getconf",
//	},

//	{ "fwaddr",	cmdfwaddr,	1,		/*[0xE2]*/
//	  "fwaddr [track [mode [npa]]]",
//	},
//	{ "treserve",	cmdtreserve,	1,		/*[0xE4]*/
//	  "treserve nbytes",
//	},
//	{ "trackinfo",	cmdtrackinfo,	1,		/*[0xE5]*/
//	  "trackinfo [track]",
//	},
//	{ "wtrack",	cmdwtrack,	1,		/*[0xE6]*/
//	  "wtrack [|]file [nbytes [track [mode]]]",
//	},
//	{ "load",	cmdload,	1,		/*[0xE7]*/
//	  "load",
//	},
//	{ "unload",	cmdunload,	1,		/*[0xE7]*/
//	  "unload",
//	},
//	{ "fixation",	cmdfixation,	1,		/*[0xE9]*/
//	  "fixation [toc-type]",
//	},
	{ "einit",	cmdeinit,	1,		/*[0x07]*/
	  "einit",
	},
	{ "estatus",	cmdestatus,	1,		/*[0xB8]*/
	  "estatus",
	},
	{ "mmove",	cmdmmove,	1,		/*[0xA5]*/
	  "mmove transport source destination [invert]",
	},

	{ "help",	cmdhelp,	0,
	  "help",
	},
	{ "probe",	cmdprobe,	0,
	  "probe",
	},
	{ "close",	cmdclose,	1,
	  "close",
	},
	{ "open",	cmdopen,	0,
	  "open [-r] sddev",
	},
	{ 0, 0 },
};

#define	SEP(c)	(((c)==' ')||((c)=='\t')||((c)=='\n'))

static char *
tokenise(char *s, char **start, char **end)
{
	char *to;
	Rune r;
	int n;

	while(*s && SEP(*s))				/* skip leading white space */
		s++;
	to = *start = s;
	while(*s){
		n = chartorune(&r, s);
		if(SEP(r)){
			if(to != *start)		/* we have data */
				break;
			s += n;				/* null string - keep looking */
			while(*s && SEP(*s))
				s++;
			to = *start = s;
		}
		else if(r == '\''){
			s += n;				/* skip leading quote */
			while(*s){
				n = chartorune(&r, s);
				if(r == '\''){
					if(s[1] != '\'')
						break;
					s++;		/* embedded quote */
				}
				while (n--)
					*to++ = *s++;
			}
			if(!*s)				/* no trailing quote */
				break;
			s++;				/* skip trailing quote */
		}
		else  {
			while(n--)
				*to++ = *s++;
		}
	}
	*end = to;
	return s;
}

static int
parse(char *s, char *fields[], int nfields)
{
	int c, argc;
	char *start, *end;

	argc = 0;
	c = *s;
	while(c){
		s = tokenise(s, &start, &end);
		c = *s++;
		if(*start == 0)
			break;
		if(argc >= nfields-1)
			return -1;
		*end = 0;
		fields[argc++] = start;
	}
	fields[argc] = 0;
	return argc;
}

static void
usage(void)
{
	fprint(2, "usage: %s [-6eq] [-m maxiosize] [[-r] /dev/sdXX]\n", argv0);
	exits("usage");
}

static struct {
	int	status;
	char*	description;
} description[] = {
	STnomem,	"buffer allocation failed",
	STtimeout,	"bus timeout",
	STharderr,	"controller error of some kind",
	STok,		"good",
	STcheck,	"check condition",
	STcondmet,	"condition met/good",
	STbusy,		"busy ",
	STintok,	"intermediate/good",
	STintcondmet,	"intermediate/condition met/good",
	STresconf,	"reservation conflict",
	STterminated,	"command terminated",
	STqfull,	"queue full",

	Status_SD,	"sense-data available",
	Status_SW,	"internal software error",
	Status_BADARG,	"bad argument to request",

	0, 0,
};

void
main(int argc, char *argv[])
{
	ScsiReq target;
	char *ap, *av[256];
	int ac, i, raw = 0;
	ScsiCmd *cp;
	long status;

	ARGBEGIN {
	case 'e':
		exabyte = 1;
		/* fallthrough */
	case '6':
		force6bytecmds = 1;
		break;
	case 'm':
		ap = ARGF();
		if(ap == nil)
			usage();
		maxiosize = atol(ap);
		if(maxiosize < 512 || maxiosize > MaxIOsize)
			sysfatal("max-xfer < 512 or > %d", MaxIOsize);
		break;
	case 'r':			/* must be last option and not bundled */
		raw++;
		break;
	case 'q':
		verbose = 0;
		break;
	default:
		usage();
	} ARGEND

	if(Binit(&bin, 0, OREAD) == Beof || Binit(&bout, 1, OWRITE) == Beof){
		fprint(2, "%s: can't init bio: %r\n", argv0);
		exits("Binit");
	}

	memset(&target, 0, sizeof(target));
	if (raw) {			/* hack for -r */
		++argc;
		--argv;
	}
	if(argc && cmdopen(&target, argc, argv) == -1) {
		fprint(2, "open failed\n");
		usage();
	}
	Bflush(&bout);

	while(ap = Brdline(&bin, '\n')){
		ap[Blinelen(&bin)-1] = 0;
		switch(ac = parse(ap, av, nelem(av))){

		default:
			for(cp = scsicmd; cp->name; cp++){
				if(strcmp(cp->name, av[0]) == 0)
					break;
			}
			if(cp->name == 0){
				Bprint(&bout, "eh?\n");
				break;
			}
			if((target.flags & Fopen) == 0 && cp->open){
				Bprint(&bout, "no current target\n");
				break;
			}
			if((status = (*cp->f)(&target, ac-1, &av[1])) != -1){
				if(verbose)
					Bprint(&bout, "ok %ld\n", status);
				break;
			}
			for(i = 0; description[i].description; i++){
				if(target.status != description[i].status)
					continue;
				if(target.status == Status_SD)
					makesense(&target);
				else
					Bprint(&bout, "%s\n", description[i].description);
				break;
			}
			break;

		case -1:
			Bprint(&bout, "eh?\n");
			break;

		case 0:
			break;
		}
		Bflush(&bout);
	}
	exits(0);
}