xref: /csrg-svn/sys/stand.att/sys.c (revision 6068)

/*	sys.c	4.5	82/03/07	*/

#include "../h/param.h"
#include "../h/inode.h"
#include "../h/fs.h"
#include "../h/ndir.h"
#include "saio.h"

ino_t	dlook();

struct dirstuff {
	int loc;
	struct iob *io;
};

static
openi(n,io)
	register struct iob *io;
{
	register struct dinode *dp;

	io->i_offset = 0;
	io->i_bn = fsbtodb(&io->i_fs, itod(&io->i_fs, n)) + io->i_boff;
	io->i_cc = io->i_fs.fs_bsize;
	io->i_ma = io->i_buf;
	devread(io);
	dp = (struct dinode *)io->i_buf;
	io->i_ino.i_ic = dp[itoo(&io->i_fs, n)].di_ic;
}

static
find(path, file)
	register char *path;
	struct iob *file;
{
	register char *q;
	char c;
	int n;

	if (path==NULL || *path=='\0') {
		printf("null path\n");
		return(0);
	}

	openi((ino_t) ROOTINO, file);
	while (*path) {
		while (*path == '/')
			path++;
		q = path;
		while(*q != '/' && *q != '\0')
			q++;
		c = *q;
		*q = '\0';

		if ((n=dlook(path, file))!=0) {
			if (c=='\0')
				break;
			openi(n, file);
			*q = c;
			path = q;
			continue;
		} else {
			printf("%s not found\n",path);
			return(0);
		}
	}
	return(n);
}

static daddr_t
sbmap(io, bn)
	register struct iob *io;
	daddr_t bn;
{
	register struct inode *ip;
	int i, j, sh;
	daddr_t nb, *bap;

	ip = &io->i_ino;
	if (bn < 0) {
		printf("bn negative\n");
		return((daddr_t)0);
	}

	/*
	 * blocks 0..NDADDR are direct blocks
	 */
	if(bn < NDADDR) {
		nb = ip->i_db[bn];
		return(nb);
	}

	/*
	 * addresses NIADDR have single and double indirect blocks.
	 * the first step is to determine how many levels of indirection.
	 */
	sh = 1;
	bn -= NDADDR;
	for (j = NIADDR; j > 0; j--) {
		sh *= NINDIR(&io->i_fs);
		if (bn < sh)
			break;
		bn -= sh;
	}
	if (j == 0) {
		printf("bn ovf %D\n", bn);
		return ((daddr_t)0);
	}

	/*
	 * fetch the first indirect block address from the inode
	 */
	nb = ip->i_ib[NIADDR - j];
	if (nb == 0) {
		printf("bn void %D\n",bn);
		return((daddr_t)0);
	}

	/*
	 * fetch through the indirect blocks
	 */
	for (; j <= NIADDR; j++) {
		if (blknos[j] != nb) {
			io->i_bn = fsbtodb(&io->i_fs, nb) + io->i_boff;
			io->i_ma = b[j];
			io->i_cc = io->i_fs.fs_bsize;
			devread(io);
			blknos[j] = nb;
		}
		bap = (daddr_t *)b[j];
		sh /= NINDIR(&io->i_fs);
		i = (bn / sh) % NINDIR(&io->i_fs);
		nb = bap[i];
		if(nb == 0) {
			printf("bn void %D\n",bn);
			return((daddr_t)0);
		}
	}
	return(nb);
}

static ino_t
dlook(s, io)
	char *s;
	register struct iob *io;
{
	register struct direct *dp;
	register struct inode *ip;
	struct dirstuff dirp;
	int len;

	if (s == NULL || *s == '\0')
		return(0);
	ip = &io->i_ino;
	if ((ip->i_mode&IFMT) != IFDIR) {
		printf("not a directory\n");
		return(0);
	}
	if (ip->i_size == 0) {
		printf("zero length directory\n");
		return(0);
	}
	len = strlen(s);
	dirp.loc = 0;
	dirp.io = io;
	for (dp = readdir(&dirp); dp != NULL; dp = readdir(&dirp)) {
		if(dp->d_ino == 0)
			continue;
		if (dp->d_namlen == len && !strcmp(s, dp->d_name))
			return(dp->d_ino);
	}
	return(0);
}

/*
 * get next entry in a directory.
 */
struct direct *
readdir(dirp)
	register struct dirstuff *dirp;
{
	register struct direct *dp;
	register struct iob *io;
	daddr_t lbn, d;
	int off;

	io = dirp->io;
	for(;;) {
		if (dirp->loc >= io->i_ino.i_size)
			return NULL;
		off = blkoff(&io->i_fs, dirp->loc);
		if (off == 0) {
			lbn = lblkno(&io->i_fs, dirp->loc);
			d = sbmap(io, lbn);
			if(d == 0)
				return NULL;
			io->i_bn = fsbtodb(&io->i_fs, d) + io->i_boff;
			io->i_ma = io->i_buf;
			io->i_cc = blksize(&io->i_fs, &io->i_ino, lbn);
			devread(io);
		}
		dp = (struct direct *)(io->i_buf + off);
		dirp->loc += dp->d_reclen;
		if (dp->d_ino == 0)
			continue;
		return (dp);
	}
}

lseek(fdesc, addr, ptr)
	int	fdesc;
	off_t	addr;
	int	ptr;
{
	register struct iob *io;

	if (ptr != 0) {
		printf("Seek not from beginning of file\n");
		return(-1);
	}
	fdesc -= 3;
	if (fdesc < 0 || fdesc >= NFILES ||
	    ((io = &iob[fdesc])->i_flgs & F_ALLOC) == 0)
		return(-1);
	io->i_offset = addr;
	io->i_bn = addr / DEV_BSIZE;
	io->i_cc = 0;
	return(0);
}

getc(fdesc)
	int	fdesc;
{
	register struct iob *io;
	register struct fs *fs;
	register char *p;
	int c, lbn, off, size, diff;


	if (fdesc >= 0 && fdesc <= 2)
		return(getchar());
	fdesc -= 3;
	if (fdesc < 0 || fdesc >= NFILES ||
	    ((io = &iob[fdesc])->i_flgs&F_ALLOC) == 0)
		return(-1);
	p = io->i_ma;
	if (io->i_cc <= 0) {
		if ((io->i_flgs & F_FILE) != 0) {
			diff = io->i_ino.i_size - io->i_offset;
			if (diff <= 0)
				return (-1);
			fs = &io->i_fs;
			lbn = lblkno(fs, io->i_offset);
			io->i_bn = fsbtodb(fs, sbmap(io, lbn)) + io->i_boff;
			off = blkoff(fs, io->i_offset);
			size = blksize(fs, &io->i_ino, lbn);
		} else {
			io->i_bn = io->i_offset / DEV_BSIZE;
			off = 0;
			size = DEV_BSIZE;
		}
		io->i_ma = io->i_buf;
		io->i_cc = size;
		devread(io);
		if ((io->i_flgs & F_FILE) != 0) {
			if (io->i_offset - off + size >= io->i_ino.i_size)
				io->i_cc = diff + off;
			io->i_cc -= off;
		}
		p = &io->i_buf[off];
	}
	io->i_cc--;
	io->i_offset++;
	c = (unsigned)*p++;
	io->i_ma = p;
	return(c);
}

/* does this port?
getw(fdesc)
	int	fdesc;
{
	register w,i;
	register char *cp;
	int val;

	for (i = 0, val = 0, cp = &val; i < sizeof(val); i++) {
		w = getc(fdesc);
		if (w < 0) {
			if (i == 0)
				return(-1);
			else
				return(val);
		}
		*cp++ = w;
	}
	return(val);
}
*/

read(fdesc, buf, count)
	int	fdesc;
	char	*buf;
	int	count;
{
	register i;
	register struct iob *file;

	if (fdesc >= 0 & fdesc <= 2) {
		i = count;
		do {
			*buf = getchar();
		} while (--i && *buf++ != '\n');
		return(count - i);
	}
	fdesc -= 3;
	if (fdesc < 0 || fdesc >= NFILES ||
	    ((file = &iob[fdesc])->i_flgs&F_ALLOC) == 0)
		return(-1);
	if ((file->i_flgs&F_READ) == 0)
		return(-1);
	if ((file->i_flgs & F_FILE) == 0) {
		file->i_cc = count;
		file->i_ma = buf;
		i = devread(file);
		file->i_bn += (count / DEV_BSIZE);
		return(i);
	} else {
		if (file->i_offset+count > file->i_ino.i_size)
			count = file->i_ino.i_size - file->i_offset;
		if ((i = count) <= 0)
			return(0);
		do {
			*buf++ = getc(fdesc+3);
		} while (--i);
		return(count);
	}
}

write(fdesc, buf, count)
	int	fdesc;
	char	*buf;
	int	count;
{
	register i;
	register struct iob *file;

	if (fdesc >= 0 && fdesc <= 2) {
		i = count;
		while (i--)
			putchar(*buf++);
		return(count);
	}
	fdesc -= 3;
	if (fdesc < 0 || fdesc >= NFILES ||
	    ((file = &iob[fdesc])->i_flgs&F_ALLOC) == 0)
		return(-1);
	if ((file->i_flgs&F_WRITE) == 0)
		return(-1);
	file->i_cc = count;
	file->i_ma = buf;
	i = devwrite(file);
	file->i_bn += (count / DEV_BSIZE);
	return(i);
}

int	openfirst = 1;

open(str, how)
	char *str;
	int	how;
{
	register char *cp;
	int i;
	register struct iob *file;
	register struct devsw *dp;
	int	fdesc;
	long	atol();

	if (openfirst) {
		for (i = 0; i < NFILES; i++)
			iob[i].i_flgs = 0;
		openfirst = 0;
	}

	for (fdesc = 0; fdesc < NFILES; fdesc++)
		if (iob[fdesc].i_flgs == 0)
			goto gotfile;
	_stop("No more file slots");
gotfile:
	(file = &iob[fdesc])->i_flgs |= F_ALLOC;

	for (cp = str; *cp && *cp != '('; cp++)
			;
	if (*cp != '(') {
		printf("Bad device\n");
		file->i_flgs = 0;
		return(-1);
	}
	*cp++ = '\0';
	for (dp = devsw; dp->dv_name; dp++) {
		if (!strcmp(str, dp->dv_name))
			goto gotdev;
	}
	printf("Unknown device\n");
	file->i_flgs = 0;
	return(-1);
gotdev:
	*(cp-1) = '(';
	file->i_ino.i_dev = dp-devsw;
	file->i_unit = *cp++ - '0';
	if (*cp >= '0' && *cp <= '9')
		file->i_unit = file->i_unit * 10 + *cp++ - '0';
	if (file->i_unit < 0 || file->i_unit > 31) {
		printf("Bad unit specifier\n");
		file->i_flgs = 0;
		return(-1);
	}
	if (*cp++ != ',') {
badoff:
		printf("Missing offset specification\n");
		file->i_flgs = 0;
		return(-1);
	}
	file->i_boff = atol(cp);
	for (;;) {
		if (*cp == ')')
			break;
		if (*cp++)
			continue;
		goto badoff;
	}
	devopen(file);
	if (*++cp == '\0') {
		file->i_flgs |= how+1;
		file->i_cc = 0;
		file->i_offset = 0;
		return(fdesc+3);
	}
	file->i_ma = (char *)(&file->i_fs);
	file->i_cc = SBSIZE;
	file->i_bn = SBLOCK;
	file->i_offset = 0;
	devread(file);
	if ((i = find(cp, file)) == 0) {
		file->i_flgs = 0;
		return(-1);
	}
	if (how != 0) {
		printf("Can't write files yet.. Sorry\n");
		file->i_flgs = 0;
		return(-1);
	}
	openi(i, file);
	file->i_offset = 0;
	file->i_cc = 0;
	file->i_flgs |= F_FILE | (how+1);
	return(fdesc+3);
}

close(fdesc)
	int	fdesc;
{
	struct iob *file;

	fdesc -= 3;
	if (fdesc < 0 || fdesc >= NFILES ||
	    ((file = &iob[fdesc])->i_flgs&F_ALLOC) == 0)
		return(-1);
	if ((file->i_flgs&F_FILE) == 0)
		devclose(file);
	file->i_flgs = 0;
	return(0);
}

exit()
{
	_stop("Exit called");
}

_stop(s)
	char	*s;
{
	int i;

	for (i = 0; i < NFILES; i++)
		if (iob[i].i_flgs != 0)
			close(i);
	printf("%s\n", s);
	_rtt();
}

trap(ps)
	int ps;
{
	printf("Trap %o\n", ps);
	for (;;)
		;
}