298 lines
7.5 KiB
C
298 lines
7.5 KiB
C
/*
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* Copyright (c) 1998 Michael Smith.
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* Copyright (c) 2000 Maxim Sobolev
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "stand.h"
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#include <sys/stat.h>
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#include <string.h>
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#include <_bzlib.h>
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#define BZ_BUFSIZE 2048 /* XXX larger? */
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struct bz_file
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{
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int bzf_rawfd;
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bz_stream bzf_bzstream;
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char bzf_buf[BZ_BUFSIZE];
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};
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static int bzf_fill(struct bz_file *z);
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static int bzf_open(const char *path, struct open_file *f);
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static int bzf_close(struct open_file *f);
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static int bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
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static off_t bzf_seek(struct open_file *f, off_t offset, int where);
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static int bzf_stat(struct open_file *f, struct stat *sb);
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struct fs_ops bzipfs_fsops = {
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"bzip",
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bzf_open,
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bzf_close,
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bzf_read,
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null_write,
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bzf_seek,
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bzf_stat,
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null_readdir
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};
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#if 0
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void *
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calloc(int items, size_t size)
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{
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return(malloc(items * size));
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}
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#endif
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static int
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bzf_fill(struct bz_file *bzf)
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{
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int result;
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int req;
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req = BZ_BUFSIZE - bzf->bzf_bzstream.avail_in;
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result = 0;
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/* If we need more */
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if (req > 0) {
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/* move old data to bottom of buffer */
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if (req < BZ_BUFSIZE)
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bcopy(bzf->bzf_buf + req, bzf->bzf_buf, BZ_BUFSIZE - req);
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/* read to fill buffer and update availibility data */
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result = read(bzf->bzf_rawfd, bzf->bzf_buf + bzf->bzf_bzstream.avail_in, req);
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bzf->bzf_bzstream.next_in = bzf->bzf_buf;
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if (result >= 0)
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bzf->bzf_bzstream.avail_in += result;
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}
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return(result);
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}
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/*
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* Adapted from get_byte/check_header in libz
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*
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* Returns 0 if the header is OK, nonzero if not.
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*/
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static int
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get_byte(struct bz_file *bzf)
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{
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if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1))
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return(-1);
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bzf->bzf_bzstream.avail_in--;
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return(*(bzf->bzf_bzstream.next_in)++);
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}
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static int bz_magic[3] = {'B', 'Z', 'h'}; /* bzip2 magic header */
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static int
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check_header(struct bz_file *bzf)
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{
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unsigned int len;
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int c;
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/* Check the bzip2 magic header */
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for (len = 0; len < 3; len++) {
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c = get_byte(bzf);
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if (c != bz_magic[len]) {
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return(1);
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}
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}
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/* Check that the block size is valid */
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c = get_byte(bzf);
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if (c < '1' || c > '9')
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return(1);
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/* Put back bytes that we've took from the input stream */
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bzf->bzf_bzstream.next_in -= 4;
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bzf->bzf_bzstream.avail_in += 4;
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return(0);
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}
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static int
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bzf_open(const char *fname, struct open_file *f)
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{
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static char *bzfname;
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int rawfd;
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struct bz_file *bzf;
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char *cp;
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int error;
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struct stat sb;
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/* Have to be in "just read it" mode */
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if (f->f_flags != F_READ)
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return(EPERM);
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/* If the name already ends in .gz or .bz2, ignore it */
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if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
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|| !strcmp(cp, ".bz2")))
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return(ENOENT);
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/* Construct new name */
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bzfname = malloc(strlen(fname) + 5);
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sprintf(bzfname, "%s.bz2", fname);
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/* Try to open the compressed datafile */
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rawfd = open(bzfname, O_RDONLY);
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free(bzfname);
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if (rawfd == -1)
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return(ENOENT);
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if (fstat(rawfd, &sb) < 0) {
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printf("bzf_open: stat failed\n");
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close(rawfd);
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return(ENOENT);
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}
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if (!S_ISREG(sb.st_mode)) {
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printf("bzf_open: not a file\n");
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close(rawfd);
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return(EISDIR); /* best guess */
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}
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/* Allocate a bz_file structure, populate it */
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bzf = malloc(sizeof(struct bz_file));
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bzero(bzf, sizeof(struct bz_file));
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bzf->bzf_rawfd = rawfd;
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/* Verify that the file is bzipped (XXX why do this afterwards?) */
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if (check_header(bzf)) {
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close(bzf->bzf_rawfd);
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BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
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free(bzf);
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return(EFTYPE);
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}
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/* Initialise the inflation engine */
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if ((error = BZ2_bzDecompressInit(&(bzf->bzf_bzstream), 0, 1)) != BZ_OK) {
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printf("bzf_open: BZ2_bzDecompressInit returned %d\n", error);
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close(bzf->bzf_rawfd);
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free(bzf);
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return(EIO);
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}
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/* Looks OK, we'll take it */
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f->f_fsdata = bzf;
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return(0);
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}
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static int
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bzf_close(struct open_file *f)
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{
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struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
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BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
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close(bzf->bzf_rawfd);
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free(bzf);
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return(0);
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}
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static int
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bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
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{
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struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
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int error;
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bzf->bzf_bzstream.next_out = buf; /* where and how much */
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bzf->bzf_bzstream.avail_out = size;
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while (bzf->bzf_bzstream.avail_out) {
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if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1)) {
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printf("bzf_read: fill error\n");
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return(-1);
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}
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if (bzf->bzf_bzstream.avail_in == 0) { /* oops, unexpected EOF */
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printf("bzf_read: unexpected EOF\n");
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break;
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}
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error = BZ2_bzDecompress(&bzf->bzf_bzstream); /* decompression pass */
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if (error == BZ_STREAM_END) { /* EOF, all done */
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break;
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}
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if (error != BZ_OK) { /* argh, decompression error */
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printf("bzf_read: BZ2_bzDecompress returned %d\n", error);
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errno = EIO;
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return(-1);
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}
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}
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if (resid != NULL)
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*resid = bzf->bzf_bzstream.avail_out;
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return(0);
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}
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static off_t
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bzf_seek(struct open_file *f, off_t offset, int where)
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{
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struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
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off_t target;
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char discard[16];
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switch (where) {
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case SEEK_SET:
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target = offset;
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break;
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case SEEK_CUR:
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target = offset + bzf->bzf_bzstream.total_out_lo32;
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break;
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default:
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target = -1;
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}
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/* Can we get there from here? */
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if (target < bzf->bzf_bzstream.total_out_lo32) {
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errno = EOFFSET;
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return -1;
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}
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/* skip forwards if required */
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while (target > bzf->bzf_bzstream.total_out_lo32) {
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if (bzf_read(f, discard, min(sizeof(discard), target - bzf->bzf_bzstream.total_out_lo32), NULL) == -1)
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return(-1);
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}
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/* This is where we are (be honest if we overshot) */
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return (bzf->bzf_bzstream.total_out_lo32);
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}
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static int
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bzf_stat(struct open_file *f, struct stat *sb)
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{
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struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
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int result;
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/* stat as normal, but indicate that size is unknown */
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if ((result = fstat(bzf->bzf_rawfd, sb)) == 0)
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sb->st_size = -1;
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return(result);
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}
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void
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bz_internal_error(int errorcode)
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{
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panic("bzipfs: critical error %d in bzip2 library occured\n", errorcode);
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}
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