FreeBSD-5.3/lib/libstand/bzipfs.c
/*
* Copyright (c) 1998 Michael Smith.
* Copyright (c) 2000 Maxim Sobolev
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libstand/bzipfs.c,v 1.6 2004/01/21 20:12:23 jhb Exp $");
#include "stand.h"
#include <sys/stat.h>
#include <string.h>
#include <_bzlib.h>
#define BZ_BUFSIZE 2048 /* XXX larger? */
struct bz_file
{
int bzf_rawfd;
bz_stream bzf_bzstream;
char bzf_buf[BZ_BUFSIZE];
};
static int bzf_fill(struct bz_file *z);
static int bzf_open(const char *path, struct open_file *f);
static int bzf_close(struct open_file *f);
static int bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t bzf_seek(struct open_file *f, off_t offset, int where);
static int bzf_stat(struct open_file *f, struct stat *sb);
struct fs_ops bzipfs_fsops = {
"bzip",
bzf_open,
bzf_close,
bzf_read,
null_write,
bzf_seek,
bzf_stat,
null_readdir
};
#if 0
void *
calloc(int items, size_t size)
{
return(malloc(items * size));
}
#endif
static int
bzf_fill(struct bz_file *bzf)
{
int result;
int req;
req = BZ_BUFSIZE - bzf->bzf_bzstream.avail_in;
result = 0;
/* If we need more */
if (req > 0) {
/* move old data to bottom of buffer */
if (req < BZ_BUFSIZE)
bcopy(bzf->bzf_buf + req, bzf->bzf_buf, BZ_BUFSIZE - req);
/* read to fill buffer and update availibility data */
result = read(bzf->bzf_rawfd, bzf->bzf_buf + bzf->bzf_bzstream.avail_in, req);
bzf->bzf_bzstream.next_in = bzf->bzf_buf;
if (result >= 0)
bzf->bzf_bzstream.avail_in += result;
}
return(result);
}
/*
* Adapted from get_byte/check_header in libz
*
* Returns 0 if the header is OK, nonzero if not.
*/
static int
get_byte(struct bz_file *bzf)
{
if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1))
return(-1);
bzf->bzf_bzstream.avail_in--;
return(*(bzf->bzf_bzstream.next_in)++);
}
static int bz_magic[3] = {'B', 'Z', 'h'}; /* bzip2 magic header */
static int
check_header(struct bz_file *bzf)
{
unsigned int len;
int c;
/* Check the bzip2 magic header */
for (len = 0; len < 3; len++) {
c = get_byte(bzf);
if (c != bz_magic[len]) {
return(1);
}
}
/* Check that the block size is valid */
c = get_byte(bzf);
if (c < '1' || c > '9')
return(1);
/* Put back bytes that we've took from the input stream */
bzf->bzf_bzstream.next_in -= 4;
bzf->bzf_bzstream.avail_in += 4;
return(0);
}
static int
bzf_open(const char *fname, struct open_file *f)
{
static char *bzfname;
int rawfd;
struct bz_file *bzf;
char *cp;
int error;
struct stat sb;
/* Have to be in "just read it" mode */
if (f->f_flags != F_READ)
return(EPERM);
/* If the name already ends in .gz or .bz2, ignore it */
if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
|| !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
return(ENOENT);
/* Construct new name */
bzfname = malloc(strlen(fname) + 5);
sprintf(bzfname, "%s.bz2", fname);
/* Try to open the compressed datafile */
rawfd = open(bzfname, O_RDONLY);
free(bzfname);
if (rawfd == -1)
return(ENOENT);
if (fstat(rawfd, &sb) < 0) {
printf("bzf_open: stat failed\n");
close(rawfd);
return(ENOENT);
}
if (!S_ISREG(sb.st_mode)) {
printf("bzf_open: not a file\n");
close(rawfd);
return(EISDIR); /* best guess */
}
/* Allocate a bz_file structure, populate it */
bzf = malloc(sizeof(struct bz_file));
bzero(bzf, sizeof(struct bz_file));
bzf->bzf_rawfd = rawfd;
/* Verify that the file is bzipped (XXX why do this afterwards?) */
if (check_header(bzf)) {
close(bzf->bzf_rawfd);
BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
free(bzf);
return(EFTYPE);
}
/* Initialise the inflation engine */
if ((error = BZ2_bzDecompressInit(&(bzf->bzf_bzstream), 0, 1)) != BZ_OK) {
printf("bzf_open: BZ2_bzDecompressInit returned %d\n", error);
close(bzf->bzf_rawfd);
free(bzf);
return(EIO);
}
/* Looks OK, we'll take it */
f->f_fsdata = bzf;
return(0);
}
static int
bzf_close(struct open_file *f)
{
struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
close(bzf->bzf_rawfd);
free(bzf);
return(0);
}
static int
bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
{
struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
int error;
bzf->bzf_bzstream.next_out = buf; /* where and how much */
bzf->bzf_bzstream.avail_out = size;
while (bzf->bzf_bzstream.avail_out) {
if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1)) {
printf("bzf_read: fill error\n");
return(EIO);
}
if (bzf->bzf_bzstream.avail_in == 0) { /* oops, unexpected EOF */
printf("bzf_read: unexpected EOF\n");
if (bzf->bzf_bzstream.avail_out == size)
return (EIO);
break;
}
error = BZ2_bzDecompress(&bzf->bzf_bzstream); /* decompression pass */
if (error == BZ_STREAM_END) { /* EOF, all done */
break;
}
if (error != BZ_OK) { /* argh, decompression error */
printf("bzf_read: BZ2_bzDecompress returned %d\n", error);
return(EIO);
}
}
if (resid != NULL)
*resid = bzf->bzf_bzstream.avail_out;
return(0);
}
static off_t
bzf_seek(struct open_file *f, off_t offset, int where)
{
struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
off_t target;
char discard[16];
switch (where) {
case SEEK_SET:
target = offset;
break;
case SEEK_CUR:
target = offset + bzf->bzf_bzstream.total_out_lo32;
break;
case SEEK_END:
target = -1;
default:
errno = EINVAL;
return (-1);
}
/* Can we get there from here? */
if (target < bzf->bzf_bzstream.total_out_lo32) {
errno = EOFFSET;
return -1;
}
/* skip forwards if required */
while (target > bzf->bzf_bzstream.total_out_lo32) {
errno = bzf_read(f, discard, min(sizeof(discard),
target - bzf->bzf_bzstream.total_out_lo32), NULL);
if (errno)
return(-1);
}
/* This is where we are (be honest if we overshot) */
return (bzf->bzf_bzstream.total_out_lo32);
}
static int
bzf_stat(struct open_file *f, struct stat *sb)
{
struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
int result;
/* stat as normal, but indicate that size is unknown */
if ((result = fstat(bzf->bzf_rawfd, sb)) == 0)
sb->st_size = -1;
return(result);
}
void
bz_internal_error(int errorcode)
{
panic("bzipfs: critical error %d in bzip2 library occured\n", errorcode);
}