/*
 * Copyright (c) 1983, 1987 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)disklabel.c	5.17.1 (2.11BSD) 4/10/95";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/errno.h>
#include <sys/fs.h>
#include <sys/file.h>
#include <sys/uio.h>

#define DKTYPENAMES
#include <sys/disklabel.h>
#include <stdio.h>
#include <string.h>

extern	int	errno;

static	char *dgetstr();
static	dgetent();
static	dnamatch();
static	long dgetnum(), _gtnumdflt();
static	dgetflag();
static	gettype();
static	error();

#define getnumdflt(field, dname, dflt) field=_gtnumdflt(dname,(long)dflt)

struct disklabel *
getdiskbyname(name)
	char *name;
{
	static struct	disklabel disk;
	static char 	boot[MAXPATHLEN];
	char	localbuf[256];	/* BUFSIZ reduced to save stack space */
	char	buf[BUFSIZ];
	char	*cp, *cq;	/* can't be register */
	register struct	disklabel *dp = &disk;
	register struct partition *pp;
	char	p, max, psize[3], pbsize[3],
		pfsize[3], poffset[3], ptype[3];
	u_long	*dx;

	if (dgetent(buf, name) <= 0)
		return ((struct disklabel *)0);
	bzero((char *)&disk, sizeof(disk));
	/*
	 * typename
	 */
	cq = dp->d_typename;
	cp = buf;
	while (cq < dp->d_typename + sizeof(dp->d_typename) - 1 &&
	    (*cq = *cp) && *cq != '|' && *cq != ':')
		cq++, cp++;
	*cq = '\0';
	/*
	 * boot name (optional)  xxboot
	 */
	cp = boot;
	dp->d_boot0 = dgetstr("b0", &cp);
	cp = localbuf;
	cq = dgetstr("ty", &cp);
	if (cq && strcmp(cq, "removable") == 0)
		dp->d_flags |= D_REMOVABLE;
	else  if (cq && strcmp(cq, "simulated") == 0)
		dp->d_flags |= D_RAMDISK;
	if (dgetflag("sf"))
		dp->d_flags |= D_BADSECT;

/*
 *	Have to do this because anything except 512 will cause chaos in
 *	disklabel(8).  disklabel(8) tries to protect itself against this
 *	but the safest thing is to fix the sector size here.  The only thing
 *	which ever used a value other than 512 was the RL02 and RL01
 *	disktab entries and they have been fixed.
*/
	
#ifdef	corrupt_filesystems
	getnumdflt(dp->d_secsize, "se", 512);
#endif
	dp->d_secsize = 512;

	dp->d_ntracks = dgetnum("nt");
	dp->d_nsectors = dgetnum("ns");
	dp->d_ncylinders = dgetnum("nc");
	cq = dgetstr("dt", &cp);
	if (cq)
		dp->d_type = gettype(cq, dktypenames);
	else
		getnumdflt(dp->d_type, "dt", 0);
	getnumdflt(dp->d_secpercyl, "sc", dp->d_nsectors * dp->d_ntracks);
	getnumdflt(dp->d_secperunit, "su", dp->d_secpercyl * dp->d_ncylinders);
	getnumdflt(dp->d_sparespertrack, "rt", 0);
	getnumdflt(dp->d_sparespercyl, "rc", 0);
	getnumdflt(dp->d_acylinders, "ac", 0);
	getnumdflt(dp->d_rpm, "rm", 3600);
	getnumdflt(dp->d_interleave, "il", 1);
	getnumdflt(dp->d_trackskew, "sk", 0);
	getnumdflt(dp->d_cylskew, "cs", 0);
	getnumdflt(dp->d_headswitch, "hs", 0);
	getnumdflt(dp->d_trkseek, "ts", 0);

/*
 * See the comments in src/bin/disklabel.c for a more detailed explaination
 * which the 'bbsize' is set to 512.  The simple explanation is that the
 * designers of disklabeling confused 'sectors' and 'filesystem blocks'. 
 * BBSIZE is set to 1024 even though the real boot area (what the boot roms
 * will read) is 512.
*/
#ifdef	boot_area_really_is_1k
	getnumdflt(dp->d_bbsize, "bs", BBSIZE);
#endif
	dp->d_bbsize = 512;

	getnumdflt(dp->d_sbsize, "sb", SBSIZE);
	strcpy(psize, "px");
	strcpy(pbsize, "bx");
	strcpy(pfsize, "fx");
	strcpy(poffset, "ox");
	strcpy(ptype, "tx");
	max = 'a' - 1;
	pp = &dp->d_partitions[0];
	for (p = 'a'; p < 'a' + MAXPARTITIONS; p++, pp++) {
		psize[1] = pbsize[1] = pfsize[1] = poffset[1] = ptype[1] = p;
		pp->p_size = dgetnum(psize);
		if (pp->p_size == -1L)
			pp->p_size = 0L;
		else {
			pp->p_offset = dgetnum(poffset);
			getnumdflt(pp->p_fsize, pfsize, 0);
			if (pp->p_fsize)
				pp->p_frag = dgetnum(pbsize) / pp->p_fsize;
			getnumdflt(pp->p_fstype, ptype, 0);
			if (pp->p_fstype == 0 && (cq = dgetstr(ptype, &cp)))
				pp->p_fstype = gettype(cq, fstypenames);
			max = p;
		}
	}
	dp->d_npartitions = max + 1 - 'a';
	(void)strcpy(psize, "dx");
	dx = dp->d_drivedata;
	for (p = '0'; p < '0' + NDDATA; p++, dx++) {
		psize[1] = p;
		getnumdflt(*dx, psize, 0);
	}
	dp->d_magic = DISKMAGIC;
	dp->d_magic2 = DISKMAGIC;
	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[512];		/* BUFSIZE - reduced to conserve stack space */
	int tf;

	tbuf = bp;
	tf = open(_PATH_DISKTAB, 0);
	if (tf < 0) {
		error(errno);
		return (-1);
	}
	for (;;) {
		cp = bp;
		for (;;) {
			if (i == cnt) {
				cnt = read(tf, ibuf, sizeof (ibuf));
				if (cnt <= 0) {
					error(errno);
					close(tf);
					return (0);
				}
				i = 0;
			}
			c = ibuf[i++];
			if (c == '\n') {
				if (cp > bp && cp[-1] == '\\'){
					cp--;
					continue;
				}
				break;
			}
			if (cp >= bp+BUFSIZ) {
				error(EFTYPE);
				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++;
	while (*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 long
dgetnum(id)
	char *id;
{
	register int base;
	long i;
	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);
	}
}

/*
 * Handle a flag option.
 * Flag options are given "naked", i.e. followed by a : or the end
 * of the buffer.  Return 1 if we find the option, or 0 if it is
 * not given.
 */
static
dgetflag(id)
	char *id;
{
	register char *bp = tbuf;

	for (;;) {
		bp = dskip(bp);
		if (!*bp)
			return (0);
		if (*bp++ == id[0] && *bp != 0 && *bp++ == id[1]) {
			if (!*bp || *bp == ':')
				return (1);
			else if (*bp == '@')
				return (0);
		}
	}
}

/*
 * 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);
}

static
gettype(t, names)
	char *t;
	char **names;
{
	register char **nm;

	for (nm = names; *nm; nm++)
		if (strcasecmp(t, *nm) == 0)
			return (nm - names);
	if (isdigit(*t))
		return (atoi(t));
	return (0);
}

static
error(err)
	int err;
{
	struct iovec iov[4];

	iov[0].iov_base = "disktab: ";
	iov[0].iov_len = 9;
	iov[1].iov_base = _PATH_DISKTAB;
	iov[1].iov_len = sizeof (_PATH_DISKTAB) -  1;
	iov[2].iov_base = strerror(err);
	iov[2].iov_len = strlen(iov[2].iov_base);
	iov[3].iov_base = "\n";
	iov[3].iov_len = 1;
	(void)writev(fileno(stderr), &iov, 4);
}

static long
_gtnumdflt(dname, dflt)
	char *dname;
	long dflt;
	{
	long f;

	f = dgetnum(dname);
	if	(f == -1L)
		f = dflt;
	return(f);
	}