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/*
* 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("$FreeBSD$");
#ifndef REGRESSION
#include "stand.h"
#else
#include <stdlib.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/types.h>
#include <sys/unistd.h>
struct open_file {
int f_flags; /* see F_* below */
void *f_fsdata; /* file system specific data */
};
#define F_READ 0x0001 /* file opened for reading */
#define EOFFSET (ELAST+8) /* relative seek not supported */
static inline u_int min(u_int a, u_int b) { return(a < b ? a : b); }
#define panic(x, y) abort()
#endif
#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];
int bzf_endseen;
};
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);
#ifndef REGRESSION
struct fs_ops bzipfs_fsops = {
"bzip",
bzf_open,
bzf_close,
bzf_read,
null_write,
bzf_seek,
bzf_stat,
null_readdir
};
#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);
if (bzfname == NULL)
return(ENOMEM);
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));
if (bzf == NULL)
return(ENOMEM);
bzero(bzf, sizeof(struct bz_file));
bzf->bzf_rawfd = rawfd;
/* Verify that the file is bzipped */
if (check_header(bzf)) {
close(bzf->bzf_rawfd);
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 && bzf->bzf_endseen == 0) {
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 */
bzf->bzf_endseen = 1;
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 int
bzf_rewind(struct open_file *f)
{
struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
struct bz_file *bzf_tmp;
/*
* Since bzip2 does not have an equivalent inflateReset function a crude
* one needs to be provided. The functions all called in such a way that
* at any time an error occurs a roll back can be done (effectively making
* this rewind 'atomic', either the reset occurs successfully or not at all,
* with no 'undefined' state happening).
*/
/* Allocate a bz_file structure, populate it */
bzf_tmp = malloc(sizeof(struct bz_file));
if (bzf_tmp == NULL)
return(-1);
bzero(bzf_tmp, sizeof(struct bz_file));
bzf_tmp->bzf_rawfd = bzf->bzf_rawfd;
/* Initialise the inflation engine */
if (BZ2_bzDecompressInit(&(bzf_tmp->bzf_bzstream), 0, 1) != BZ_OK) {
free(bzf_tmp);
return(-1);
}
/* Seek back to the beginning of the file */
if (lseek(bzf->bzf_rawfd, 0, SEEK_SET) == -1) {
BZ2_bzDecompressEnd(&(bzf_tmp->bzf_bzstream));
free(bzf_tmp);
return(-1);
}
/* Free old bz_file data */
BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
free(bzf);
/* Use the new bz_file data */
f->f_fsdata = bzf_tmp;
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;
default:
errno = EINVAL;
return(-1);
}
/* Can we get there from here? */
if (target < bzf->bzf_bzstream.total_out_lo32 && bzf_rewind(f) != 0) {
errno = EOFFSET;
return -1;
}
/* if bzf_rewind was called then bzf has changed */
bzf = (struct bz_file *)f->f_fsdata;
/* 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);
/* Break out of loop if end of file has been reached. */
if (bzf->bzf_endseen)
break;
}
/* 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", errorcode);
}
#ifdef REGRESSION
/* Small test case, open and decompress test.bz2 */
int main()
{
struct open_file f;
char buf[1024];
size_t resid;
int err;
memset(&f, '\0', sizeof(f));
f.f_flags = F_READ;
err = bzf_open("test", &f);
if (err != 0)
exit(1);
do {
err = bzf_read(&f, buf, sizeof(buf), &resid);
} while (err == 0 && resid != sizeof(buf));
if (err != 0)
exit(2);
exit(0);
}
#endif