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stand/libsa/cd9660read.c

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/*
* Copyright (C) 1996 Wolfgang Solfrank.
* Copyright (C) 1996 TooLs GmbH.
* 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 TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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.
*/
/* Originally derived from libsa/cd9660.c: */
/* $NetBSD: cd9660.c,v 1.5 1997/06/26 19:11:33 drochner Exp $ */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <fs/cd9660/iso.h>
#include <fs/cd9660/cd9660_rrip.h>
static uint64_t cd9660_lookup(const char *);
static ssize_t cd9660_fsread(uint64_t, void *, size_t);
#define SUSP_CONTINUATION "CE"
#define SUSP_PRESENT "SP"
#define SUSP_STOP "ST"
#define SUSP_EXTREF "ER"
#define RRIP_NAME "NM"
typedef struct {
ISO_SUSP_HEADER h;
u_char signature [ISODCL ( 5, 6)];
u_char len_skp [ISODCL ( 7, 7)]; /* 711 */
} ISO_SUSP_PRESENT;
static int
read_iso_block(void *buffer, daddr_t blkno)
{
return (drvread(&dsk, buffer, blkno * 4, 4));
}
static ISO_SUSP_HEADER *
susp_lookup_record(const char *identifier, struct iso_directory_record *dp,
int lenskip)
{
static char susp_buffer[ISO_DEFAULT_BLOCK_SIZE];
ISO_SUSP_HEADER *sh;
ISO_RRIP_CONT *shc;
char *p, *end;
int error;
p = dp->name + isonum_711(dp->name_len) + lenskip;
/* Names of even length have a padding byte after the name. */
if ((isonum_711(dp->name_len) & 1) == 0)
p++;
end = (char *)dp + isonum_711(dp->length);
while (p + 3 < end) {
sh = (ISO_SUSP_HEADER *)p;
if (bcmp(sh->type, identifier, 2) == 0)
return (sh);
if (bcmp(sh->type, SUSP_STOP, 2) == 0)
return (NULL);
if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
shc = (ISO_RRIP_CONT *)sh;
error = read_iso_block(susp_buffer,
isonum_733(shc->location));
/* Bail if it fails. */
if (error != 0)
return (NULL);
p = susp_buffer + isonum_733(shc->offset);
end = p + isonum_733(shc->length);
} else {
/* Ignore this record and skip to the next. */
p += isonum_711(sh->length);
/* Avoid infinite loops with corrupted file systems */
if (isonum_711(sh->length) == 0)
return (NULL);
}
}
return (NULL);
}
static const char *
rrip_lookup_name(struct iso_directory_record *dp, int lenskip, size_t *len)
{
ISO_RRIP_ALTNAME *p;
if (len == NULL)
return (NULL);
p = (ISO_RRIP_ALTNAME *)susp_lookup_record(RRIP_NAME, dp, lenskip);
if (p == NULL)
return (NULL);
switch (*p->flags) {
case ISO_SUSP_CFLAG_CURRENT:
*len = 1;
return (".");
case ISO_SUSP_CFLAG_PARENT:
*len = 2;
return ("..");
case 0:
*len = isonum_711(p->h.length) - 5;
return ((char *)p + 5);
default:
/*
* We don't handle hostnames or continued names as they are
* too hard, so just bail and use the default name.
*/
return (NULL);
}
}
static int
rrip_check(struct iso_directory_record *dp, int *lenskip)
{
ISO_SUSP_PRESENT *sp;
ISO_RRIP_EXTREF *er;
char *p;
/* First, see if we can find a SP field. */
p = dp->name + isonum_711(dp->name_len);
if (p > (char *)dp + isonum_711(dp->length)) {
return (0);
}
sp = (ISO_SUSP_PRESENT *)p;
if (bcmp(sp->h.type, SUSP_PRESENT, 2) != 0) {
return (0);
}
if (isonum_711(sp->h.length) != sizeof(ISO_SUSP_PRESENT)) {
return (0);
}
if (sp->signature[0] != 0xbe || sp->signature[1] != 0xef) {
return (0);
}
*lenskip = isonum_711(sp->len_skp);
/*
* Now look for an ER field. If RRIP is present, then there must
* be at least one of these. It would be more pedantic to walk
* through the list of fields looking for a Rock Ridge ER field.
*/
er = (ISO_RRIP_EXTREF *)susp_lookup_record(SUSP_EXTREF, dp, 0);
if (er == NULL) {
return (0);
}
return (1);
}
static int
dirmatch(const char *path, struct iso_directory_record *dp, int use_rrip,
int lenskip)
{
size_t len;
const char *cp = NULL, *name = NULL;
int i, icase;
if (use_rrip)
cp = rrip_lookup_name(dp, lenskip, &len);
else
cp = NULL;
if (cp == NULL) {
len = isonum_711(dp->name_len);
cp = dp->name;
icase = 1;
} else
icase = 0;
name = cp;
for (i = len; --i >= 0; path++, cp++) {
if (!*path || *path == '/')
break;
if (*path == *cp)
continue;
if (!icase && toupper(*path) == *cp)
continue;
return 0;
}
if (*path && *path != '/') {
return 0;
}
/*
* Allow stripping of trailing dots and the version number.
* Note that this will find the first instead of the last version
* of a file.
*/
if (i >= 0 && (*cp == ';' || *cp == '.')) {
/* This is to prevent matching of numeric extensions */
if (*cp == '.' && cp[1] != ';') {
return 0;
}
while (--i >= 0)
if (*++cp != ';' && (*cp < '0' || *cp > '9')) {
return 0;
}
}
return 1;
}
static uint64_t
cd9660_lookup(const char *path)
{
static char blkbuf[ISO_DEFAULT_BLOCK_SIZE];
struct iso_primary_descriptor *vd;
struct iso_directory_record rec;
struct iso_directory_record *dp = NULL;
size_t dsize, off;
daddr_t bno, boff;
int rc, first, use_rrip, lenskip;
uint64_t cookie;
for (bno = 16;; bno++) {
rc = read_iso_block(blkbuf, bno);
vd = (struct iso_primary_descriptor *)blkbuf;
if (bcmp(vd->id, ISO_STANDARD_ID, sizeof vd->id) != 0)
return (0);
if (isonum_711(vd->type) == ISO_VD_END)
return (0);
if (isonum_711(vd->type) == ISO_VD_PRIMARY)
break;
}
rec = *(struct iso_directory_record *) vd->root_directory_record;
if (*path == '/') path++; /* eat leading '/' */
first = 1;
use_rrip = 0;
while (*path) {
bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
dsize = isonum_733(rec.size);
off = 0;
boff = 0;
while (off < dsize) {
if ((off % ISO_DEFAULT_BLOCK_SIZE) == 0) {
rc = read_iso_block(blkbuf, bno + boff);
if (rc) {
return (0);
}
boff++;
dp = (struct iso_directory_record *) blkbuf;
}
if (isonum_711(dp->length) == 0) {
/* skip to next block, if any */
off = boff * ISO_DEFAULT_BLOCK_SIZE;
continue;
}
/* See if RRIP is in use. */
if (first)
use_rrip = rrip_check(dp, &lenskip);
if (dirmatch(path, dp, use_rrip,
first ? 0 : lenskip)) {
first = 0;
break;
} else
first = 0;
dp = (struct iso_directory_record *)
((char *) dp + isonum_711(dp->length));
/* If the new block has zero length, it is padding. */
if (isonum_711(dp->length) == 0) {
/* Skip to next block, if any. */
off = boff * ISO_DEFAULT_BLOCK_SIZE;
continue;
}
off += isonum_711(dp->length);
}
if (off >= dsize) {
return (0);
}
rec = *dp;
while (*path && *path != '/') /* look for next component */
path++;
if (*path) path++; /* skip '/' */
}
if ((isonum_711(rec.flags) & 2) != 0) {
return (0);
}
cookie = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
cookie = (cookie << 32) | isonum_733(rec.size);
return (cookie);
}
static ssize_t
cd9660_fsread(uint64_t cookie, void *buf, size_t nbytes)
{
static char blkbuf[ISO_DEFAULT_BLOCK_SIZE];
static daddr_t curstart = 0, curblk = 0;
daddr_t blk, blk_off;
off_t byte_off;
size_t size, remaining, n;
char *s;
size = cookie & 0xffffffff;
blk = (cookie >> 32) & 0xffffffff;
/* Make sure we're looking at the right file. */
if (((blk << 32) | size) != cookie) {
return (-1);
}
if (blk != curstart) {
curstart = blk;
fs_off = 0;
}
size -= fs_off;
if (size < nbytes) {
nbytes = size;
}
remaining = nbytes;
s = buf;
while (remaining > 0) {
blk_off = fs_off >> ISO_DEFAULT_BLOCK_SHIFT;
byte_off = fs_off & (ISO_DEFAULT_BLOCK_SIZE - 1);
if (curblk != curstart + blk_off) {
curblk = curstart + blk_off;
read_iso_block(blkbuf, curblk);
}
if (remaining < ISO_DEFAULT_BLOCK_SIZE - byte_off) {
n = remaining;
} else {
n = ISO_DEFAULT_BLOCK_SIZE - byte_off;
}
memcpy(s, blkbuf + byte_off, n);
remaining -= n;
s += n;
fs_off += n;
}
return (nbytes);
}