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

#include <u.h>
#include <libc.h>
#include <bio.h>

#include "scsireq.h"

#define MIN(a, b)	((a) < (b) ? (a): (b))

static char rwbuf[MaxIOsize];
static int verbose = 1;

Biobuf bin, bout;
long maxiosize = MaxIOsize;
int exabyte = 0;
int force6bytecmds = 0;

typedef struct {
	char *name;
	long (*f)(ScsiReq *, int, char *[]);
	int open;
	char *help;
} ScsiCmd;

static ScsiCmd scsicmd[];

static vlong
vlmin(vlong a, vlong b)
{
	if (a < b)
		return a;
	else
		return b;
}

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

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

static long
cmdreqsense(ScsiReq *rp, int argc, char *argv[])
{
	long nbytes;

	USED(argc, argv);
	if((nbytes = SRreqsense(rp)) != -1)
		makesense(rp);
	return nbytes;
}

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

static long
cmdrblimits(ScsiReq *rp, int argc, char *argv[])
{
	uchar l[6];
	long n;

	USED(argc, argv);
	if((n = SRrblimits(rp, l)) == -1)
		return -1;
	Bprint(&bout, " %2.2uX %2.2uX %2.2uX %2.2uX %2.2uX %2.2uX\n",
		l[0], l[1], l[2], l[3], l[4], l[5]);
	return n;
}

static int
mkfile(char *file, int omode, int *pid)
{
	int fd[2];

	if(*file != '|'){
		*pid = -1;
		if(omode == OWRITE)
			return create(file, OWRITE, 0666);
		else if(omode == OREAD)
			return open(file, OREAD);
		return -1;
	}

	file++;
	if(*file == 0 || pipe(fd) == -1)
		return -1;
	if((*pid = fork()) == -1){
		close(fd[0]);
		close(fd[1]);
		return -1;
	}
	if(*pid == 0){
		switch(omode){

		case OREAD:
			dup(fd[0], 1);
			break;

		case OWRITE:
			dup(fd[0], 0);
			break;
		}
		close(fd[0]);
		close(fd[1]);
		execl("/bin/rc", "rc", "-c", file, nil);
		exits("exec");
	}
	close(fd[0]);
	return fd[1];
}

int
waitfor(int pid)
{
	int msg;
	Waitmsg *w;

	while((w = wait()) != nil){
		if(w->pid != pid){
			free(w);
			continue;
		}
		msg = (w->msg[0] != '\0');
		free(w);
		return msg;
	}
	return -1;
}

static long
cmdread(ScsiReq *rp, int argc, char *argv[])
{
	long n, iosize, prevsize = 0;
	vlong nbytes, total;
	int fd, pid;
	char *p;

	iosize = maxiosize;
	nbytes = ~0ULL >> 1;
	switch(argc){

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

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

	case 1:
		if((fd = mkfile(argv[0], OWRITE, &pid)) == -1){
			rp->status = Status_BADARG;
			return -1;
		}
		break;
	}
	print("bsize=%lud\n", rp->lbsize);
	total = 0;
	while(nbytes){
		n = vlmin(nbytes, iosize);
		if((n = SRread(rp, rwbuf, n)) == -1){
			if(total == 0)
				total = -1;
			break;
		}
		if (n == 0)
			break;
		if (prevsize != n) {
			print("tape block size=%ld\n", n);
			prevsize = n;
		}
		if(write(fd, rwbuf, n) != n){
			if(total == 0)
				total = -1;
			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
cmdwrite(ScsiReq *rp, int argc, char *argv[])
{
	long n, prevsize = 0;
	vlong nbytes, total;
	int fd, pid;
	char *p;

	nbytes = ~0ULL >> 1;
	switch(argc){

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

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

	case 1:
		if((fd = mkfile(argv[0], OREAD, &pid)) == -1){
			rp->status = Status_BADARG;
			return -1;
		}
		break;
	}
	total = 0;
	while(nbytes){
		n = vlmin(nbytes, maxiosize);
		if((n = read(fd, rwbuf, n)) == -1){
			if(total == 0)
				total = -1;
			break;
		}
		if (n == 0)
			break;
		if (prevsize != n) {
			print("tape block size=%ld\n", n);
			prevsize = n;
		}
		if(SRwrite(rp, rwbuf, n) != n){
			if(total == 0)
				total = -1;
			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
cmdseek(ScsiReq *rp, int argc, char *argv[])
{
	char *p;
	long offset;
	int type;

	type = 0;
	switch(argc){

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

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

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

static long
cmdfilemark(ScsiReq *rp, int argc, char *argv[])
{
	char *p;
	ulong howmany;

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

static long
cmdspace(ScsiReq *rp, int argc, char *argv[])
{
	uchar code;
	long howmany;
	char option, *p;

	code = 0x00;
	howmany = 1;
	while(argc && (*argv)[0] == '-'){
		while(option = *++argv[0]){
			switch(option){

			case '-':
				break;

			case 'b':
				code = 0x00;
				break;

			case 'f':
				code = 0x01;
				break;

			default:
				rp->status = Status_BADARG;
				return -1;
			}
			break;
		}
		argc--; argv++;
		if(option == '-')
			break;
	}
	if(argc && ((howmany = strtol(argv[0], &p, 0)) == 0 && p == argv[0])){
		rp->status = Status_BADARG;
		return -1;
	}
	return SRspace(rp, code, howmany);
}

static long
cmdinquiry(ScsiReq *rp, int argc, char *argv[])
{
	long status;
	int i, n;
	uchar *p;

	USED(argc, argv);
	if((status = SRinquiry(rp)) != -1){
		n = rp->inquiry[4]+4;
		for(i = 0; i < MIN(8, n); i++)
			Bprint(&bout, " %2.2uX", rp->inquiry[i]);
		p = &rp->inquiry[8];
		n = MIN(n, sizeof(rp->inquiry)-8);
		while(n && (*p == ' ' || *p == '\t' || *p == '\n')){
			n--;
			p++;
		}
		Bprint(&bout, "\t%.*s\n", n, (char*)p);
	}
	return status;
}

static long
cmdmodeselect6(ScsiReq *rp, int argc, char *argv[])
{
	uchar list[MaxDirData];
	long nbytes, ul;
	char *p;

	memset(list, 0, sizeof(list));
	for(nbytes = 0; argc; argc--, argv++, nbytes++){
		if((ul = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		list[nbytes] = ul;

	}
	if(!(rp->flags & Finqok) && SRinquiry(rp) == -1)
		Bprint(&bout, "warning: couldn't determine whether SCSI-1/SCSI-2 mode");
	return SRmodeselect6(rp, list, nbytes);
}

static long
cmdmodeselect10(ScsiReq *rp, int argc, char *argv[])
{
	uchar list[MaxDirData];
	long nbytes, ul;
	char *p;

	memset(list, 0, sizeof(list));
	for(nbytes = 0; argc; argc--, argv++, nbytes++){
		if((ul = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		list[nbytes] = ul;

	}
	if(!(rp->flags & Finqok) && SRinquiry(rp) == -1)
		Bprint(&bout, "warning: couldn't determine whether SCSI-1/SCSI-2 mode");
	return SRmodeselect10(rp, list, nbytes);
}

static long
cmdmodesense6(ScsiReq *rp, int argc, char *argv[])
{
	uchar list[MaxDirData], *lp, page;
	long i, n, nbytes, status;
	char *p;

	nbytes = sizeof(list);
	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((page = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		break;

	case 0:
		page = 0x3F;
		break;
	}
	if((status = SRmodesense6(rp, page, list, nbytes)) == -1)
		return -1;
	lp = list;
	nbytes = list[0];
	Bprint(&bout, " Header\n   ");
	for(i = 0; i < 4; i++){				/* header */
		Bprint(&bout, " %2.2uX", *lp);
		lp++;
	}
	Bputc(&bout, '\n');

	if(list[3]){					/* block descriptors */
		for(n = 0; n < list[3]/8; n++){
			Bprint(&bout, " Block %ld\n   ", n);
			for(i = 0; i < 8; i++)
				Bprint(&bout, " %2.2uX", lp[i]);
			Bprint(&bout, "    (density %2.2uX", lp[0]);
			Bprint(&bout, " blocks %d", (lp[1]<<16)|(lp[2]<<8)|lp[3]);
			Bprint(&bout, " length %d)", (lp[5]<<16)|(lp[6]<<8)|lp[7]);
			lp += 8;
			nbytes -= 8;
			Bputc(&bout, '\n');
		}
	}

	while(nbytes > 0){				/* pages */
		i = *(lp+1);
		nbytes -= i+2;
		Bprint(&bout, " Page %2.2uX %d\n   ", *lp & 0x3F, *(lp+1));
		lp += 2;
		for(n = 0; n < i; n++){
			if(n && ((n & 0x0F) == 0))
				Bprint(&bout, "\n   ");
			Bprint(&bout, " %2.2uX", *lp);
			lp++;
		}
		if(n && (n & 0x0F))
			Bputc(&bout, '\n');
	}
	return status;
}

static long
cmdmodesense10(ScsiReq *rp, int argc, char *argv[])
{
	uchar *list, *lp, page;
	long blen, i, n, nbytes, status;
	char *p;

	nbytes = MaxDirData;
	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((page = strtoul(argv[0], &p, 0)) == 0 && p == argv[0]){
			rp->status = Status_BADARG;
			return -1;
		}
		break;

	case 0:
		page = 0x3F;
		break;
	}
	list = malloc(nbytes);
	if(list == 0){
		rp->status = STnomem;
		return -1;
	}
	if((status = SRmodesense10(rp, page, list, nbytes)) == -1)
		return -1;
	lp = list;
	nbytes = ((list[0]<<8)|list[1]);
	Bprint(&bout, " Header\n   ");
	for(i = 0; i < 8; i++){				/* header */
		Bprint(&bout, " %2.2uX", *lp);
		lp++;
	}
	Bputc(&bout, '\n');

	blen = (list[6]<<8)|list[7];
	if(blen){					/* block descriptors */
		for(n = 0; n < blen/8; n++){
			Bprint(&bout, " Block %ld\n   ", n);
			for(i = 0; i < 8; i++)
				Bprint(&bout, " %2.2uX", lp[i]);
			Bprint(&bout, "    (density %2.2uX", lp[0]);
			Bprint(&bout, " blocks %d", (lp[1]<<16)|(lp[2]<<8)|lp[3]);
			Bprint(&bout, " length %d)", (lp[5]<<16)|(lp[6]<<8)|lp[7]);
			lp += 8;
			nbytes -= 8;
			Bputc(&bout, '\n');
		}
	}

	/*
	 * Special for ATA drives, page 0 is the drive info in 16-bit
	 * chunks, little-endian, 256 in total. No decoding for now.
	 */
	if(page == 0){
		for(n = 0; n < nbytes; n += 2){
			if(n && ((n & 0x1F) == 0))
				Bprint(&bout, "\n");
			Bprint(&bout, " %4.4uX", (*(lp+1)<<8)|*lp);
			lp += 2;
		}
		Bputc(&bout, '\n');
	}
	else while(nbytes > 0){				/* pages */
		i = *(lp+1);
		nbytes -= i+2;
		Bprint(&bout, " Page %2.2uX %d\n   ", *lp & 0x3F, *(lp+1));
		lp += 2;
		for(n = 0; n < i; n++){
			if(n && ((n & 0x0F) == 0))
				Bprint(&bout, "\n   ");
			Bprint(&bout, " %2.2uX", *lp);
			lp++;
		}
		if(n && (n & 0x0F))
			Bputc(&bout, '\n');
	}
	free(list);
	return status;
}

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

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

static long
cmdstart(ScsiReq *rp, int argc, char *argv[])
{
	return start(rp, argc, argv, 1);
}

static long
cmdstop(ScsiReq *rp, int argc, char *argv[])
{
	return start(rp, argc, argv, 0);
}

static long
cmdeject(ScsiReq *rp, int argc, char *argv[])
{
	return start(rp, argc, argv, 2);
}

static long
cmdingest(ScsiReq *rp, int argc, char *argv[])
{
	return start(rp, argc, argv, 3);
}

static long
cmdcapacity(ScsiReq *rp, int argc, char *argv[])
{
	uchar d[8];
	long n;

	USED(argc, argv);
	if((n = SRrcapacity(rp, d)) == -1)
		return -1;
	Bprint(&bout, " %ud %ud\n",
		d[0]<<24|d[1]<<16|d[2]<<8|d[3],
		d[4]<<24|d[5]<<16|d[6]<<8|d[7]);
	return n;
}

static long
cmdblank(ScsiReq *rp, int argc, char *argv[])
{
	uchar type, track;
	char *sp;

	type = track = 0;
	switch(argc){

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

	case 2:
		if((type = strtoul(argv[1], &sp, 0)) == 0 && sp == argv[1]){
			rp->status = Status_BADARG;
			return -1;
		}