2.9BSD/usr/src/lib/c/gen/disktab.c

/*	@(#)disktab.c	4.2 (Berkeley) 2/8/83	*/

#include <disktab.h>
#include <stdio.h>

static	char *dgetstr();
static	long	dgetlnum();

struct disktab *
getdiskbyname(name)
	char *name;
{
	static struct disktab disk;
	static char localbuf[100];
	char *cp = localbuf;
	register struct	disktab *dp = &disk;
	register struct partition *pp;
	char p, psize[3], pstart[3];
	char buf[BUFSIZ];

	if (dgetent(buf, name) <= 0)
		return ((struct disktab *)0);
	dp->d_name = cp;
	strcpy(cp, name);
	cp += strlen(name) + 1;
	dp->d_type = dgetstr("ty", &cp);
	dp->d_secsize = dgetnum("se");
	if (dp->d_secsize < 0)
		dp->d_secsize = 512;
	dp->d_ntracks = dgetnum("nt");
	dp->d_nsectors = dgetnum("ns");
	dp->d_ncylinders = dgetnum("nc");
	dp->d_rpm = dgetnum("rm");
	if (dp->d_rpm < 0)
		dp->d_rpm = 3600;
	dp->d_nspt = dgetnum("xt");
	strcpy(psize, "px");
	strcpy(pstart, "ox");
	for (p = 'a'; p < 'i'; p++) {
		psize[1] = pstart[1] = p;
		pp = &dp->d_partitions[p - 'a'];
		pp->p_size = dgetlnum(psize);
		pp->p_start = dgetlnum(pstart);
	}
	return (dp);
}

#include <ctype.h>

static	char *tbuf;
static	char *dskip();
static	char *ddecode();

/*
 * Get an entry for disk name in buffer bp,
 * from the diskcap file.  Parse is very rudimentary;
 * we just notice escaped newlines.
 */
static
dgetent(bp, name)
	char *bp, *name;
{
	register char *cp;
	register int c;
	register int i = 0, cnt = 0;
	char ibuf[BUFSIZ];
	int tf;

	tbuf = bp;
	tf = open(DISKTAB, 0);
	if (tf < 0)
		return (-1);
	for (;;) {
		cp = bp;
		for (;;) {
			if (i == cnt) {
				cnt = read(tf, ibuf, BUFSIZ);
				if (cnt <= 0) {
					close(tf);
					return (0);
				}
				i = 0;
			}
			c = ibuf[i++];
			if (c == '\n') {
				if (cp > bp && cp[-1] == '\\'){
					cp--;
					continue;
				}
				break;
			}
			if (cp >= bp+BUFSIZ) {
				write(2,"Disktab entry too long\n", 23);
				break;
			} else
				*cp++ = c;
		}
		*cp = 0;

		/*
		 * The real work for the match.
		 */
		if (dnamatch(name)) {
			close(tf);
			return (1);
		}
	}
}

/*
 * Dnamatch deals with name matching.  The first field of the disktab
 * entry is a sequence of names separated by |'s, so we compare
 * against each such name.  The normal : terminator after the last
 * name (before the first field) stops us.
 */
static
dnamatch(np)
	char *np;
{
	register char *Np, *Bp;

	Bp = tbuf;
	if (*Bp == '#')
		return (0);
	for (;;) {
		for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
			continue;
		if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
			return (1);
		while (*Bp && *Bp != ':' && *Bp != '|')
			Bp++;
		if (*Bp == 0 || *Bp == ':')
			return (0);
		Bp++;
	}
}

/*
 * Skip to the next field.  Notice that this is very dumb, not
 * knowing about \: escapes or any such.  If necessary, :'s can be put
 * into the diskcap file in octal.
 */
static char *
dskip(bp)
	register char *bp;
{

	while (*bp && *bp != ':')
		bp++;
	if (*bp == ':')
		bp++;
	return (bp);
}

/*
 * Return the (numeric) option id.
 * Numeric options look like
 *	li#80
 * i.e. the option string is separated from the numeric value by
 * a # character.  If the option is not found we return -1.
 * Note that we handle octal numbers beginning with 0.
 */
static
dgetnum(id)
	char *id;
{
	register int i, base;
	register char *bp = tbuf;

	for (;;) {
		bp = dskip(bp);
		if (*bp == 0)
			return (-1);
		if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
			continue;
		if (*bp == '@')
			return (-1);
		if (*bp != '#')
			continue;
		bp++;
		base = 10;
		if (*bp == '0')
			base = 8;
		i = 0;
		while (isdigit(*bp))
			i *= base, i += *bp++ - '0';
		return (i);
	}
}

static long
dgetlnum(id)
	char *id;
{
	long i;
	register int base;
	register char *bp = tbuf;

	for (;;) {
		bp = dskip(bp);
		if (*bp == 0)
			return ((long) -1);
		if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
			continue;
		if (*bp == '@')
			return ((long) -1);
		if (*bp != '#')
			continue;
		bp++;
		base = 10;
		if (*bp == '0')
			base = 8;
		i = (long) 0;
		while (isdigit(*bp))
			i *= (long) base, i += (long) (*bp++ - '0');
		return (i);
	}
}

/*
 * Get a string valued option.
 * These are given as
 *	cl=^Z
 * Much decoding is done on the strings, and the strings are
 * placed in area, which is a ref parameter which is updated.
 * No checking on area overflow.
 */
static char *
dgetstr(id, area)
	char *id, **area;
{
	register char *bp = tbuf;

	for (;;) {
		bp = dskip(bp);
		if (!*bp)
			return (0);
		if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
			continue;
		if (*bp == '@')
			return (0);
		if (*bp != '=')
			continue;
		bp++;
		return (ddecode(bp, area));
	}
}

/*
 * Tdecode does the grung work to decode the
 * string capability escapes.
 */
static char *
ddecode(str, area)
	register char *str;
	char **area;
{
	register char *cp;
	register int c;
	register char *dp;
	int i;

	cp = *area;
	while ((c = *str++) && c != ':') {
		switch (c) {

		case '^':
			c = *str++ & 037;
			break;

		case '\\':
			dp = "E\033^^\\\\::n\nr\rt\tb\bf\f";
			c = *str++;
nextc:
			if (*dp++ == c) {
				c = *dp++;
				break;
			}
			dp++;
			if (*dp)
				goto nextc;
			if (isdigit(c)) {
				c -= '0', i = 2;
				do
					c <<= 3, c |= *str++ - '0';
				while (--i && isdigit(*str));
			}
			break;
		}
		*cp++ = c;
	}
	*cp++ = 0;
	str = *area;
	*area = cp;
	return (str);
}