317 lines
8.2 KiB
C
317 lines
8.2 KiB
C
/*
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* Copyright (c) 1998 Michael Smith.
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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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* $Id: zipfs.c,v 1.1.1.1 1998/08/20 08:19:55 msmith Exp $
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*
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*/
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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 <zlib.h>
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#define Z_BUFSIZE 2048 /* XXX larger? */
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struct z_file
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{
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int zf_rawfd;
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z_stream zf_zstream;
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char zf_buf[Z_BUFSIZE];
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};
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static int zf_fill(struct z_file *z);
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static int zf_open(const char *path, struct open_file *f);
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static int zf_close(struct open_file *f);
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static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
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static off_t zf_seek(struct open_file *f, off_t offset, int where);
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static int zf_stat(struct open_file *f, struct stat *sb);
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struct fs_ops zipfs_fsops = {
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"zip",
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zf_open,
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zf_close,
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zf_read,
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null_write,
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zf_seek,
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zf_stat
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};
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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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static int
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zf_fill(struct z_file *zf)
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{
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int result;
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int req;
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req = Z_BUFSIZE - zf->zf_zstream.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 < Z_BUFSIZE)
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bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
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/* read to fill buffer and update availibility data */
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result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
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zf->zf_zstream.next_in = zf->zf_buf;
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if (result >= 0)
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zf->zf_zstream.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 z_file *zf)
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{
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if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
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return(-1);
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zf->zf_zstream.avail_in--;
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return(*(zf->zf_zstream.next_in)++);
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}
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static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
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/* gzip flag byte */
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#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
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#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
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#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
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#define COMMENT 0x10 /* bit 4 set: file comment present */
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#define RESERVED 0xE0 /* bits 5..7: reserved */
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static int
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check_header(struct z_file *zf)
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{
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int method; /* method byte */
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int flags; /* flags byte */
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uInt len;
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int c;
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/* Check the gzip magic header */
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for (len = 0; len < 2; len++) {
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c = get_byte(zf);
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if (c != gz_magic[len]) {
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return(1);
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}
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}
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method = get_byte(zf);
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flags = get_byte(zf);
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if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
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return(1);
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}
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/* Discard time, xflags and OS code: */
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for (len = 0; len < 6; len++) (void)get_byte(zf);
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if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
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len = (uInt)get_byte(zf);
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len += ((uInt)get_byte(zf))<<8;
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/* len is garbage if EOF but the loop below will quit anyway */
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while (len-- != 0 && get_byte(zf) != -1) ;
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}
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if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
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while ((c = get_byte(zf)) != 0 && c != -1) ;
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}
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if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
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while ((c = get_byte(zf)) != 0 && c != -1) ;
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}
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if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
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for (len = 0; len < 2; len++) c = get_byte(zf);
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}
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/* if there's data left, we're in business */
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return((c == -1) ? 1 : 0);
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}
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static int
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zf_open(const char *fname, struct open_file *f)
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{
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static char *zfname;
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int rawfd;
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struct z_file *zf;
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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, ignore it */
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if ((cp = strrchr(fname, '.')) && !strcmp(cp, ".gz"))
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return(ENOENT);
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/* Construct new name */
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zfname = malloc(strlen(fname) + 3);
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sprintf(zfname, "%s.gz", fname);
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/* Try to open the compressed datafile */
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rawfd = open(zfname, O_RDONLY);
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free(zfname);
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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("zf_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("zf_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 z_file structure, populate it */
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zf = malloc(sizeof(struct z_file));
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bzero(zf, sizeof(struct z_file));
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zf->zf_rawfd = rawfd;
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/* Verify that the file is gzipped (XXX why do this afterwards?) */
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if (check_header(zf)) {
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close(zf->zf_rawfd);
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inflateEnd(&(zf->zf_zstream));
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free(zf);
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return(EFTYPE);
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}
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/* Initialise the inflation engine */
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if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
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printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
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close(zf->zf_rawfd);
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free(zf);
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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 = zf;
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return(0);
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}
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static int
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zf_close(struct open_file *f)
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{
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struct z_file *zf = (struct z_file *)f->f_fsdata;
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inflateEnd(&(zf->zf_zstream));
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close(zf->zf_rawfd);
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free(zf);
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return(0);
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}
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static int
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zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
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{
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struct z_file *zf = (struct z_file *)f->f_fsdata;
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int error;
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zf->zf_zstream.next_out = buf; /* where and how much */
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zf->zf_zstream.avail_out = size;
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while (zf->zf_zstream.avail_out) {
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if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
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printf("zf_read: fill error\n");
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return(-1);
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}
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if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
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printf("zf_read: unexpected EOF\n");
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break;
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}
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error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
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if (error == Z_STREAM_END) { /* EOF, all done */
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break;
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}
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if (error != Z_OK) { /* argh, decompression error */
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printf("inflate: %s\n", zf->zf_zstream.msg);
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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 = zf->zf_zstream.avail_out;
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return(0);
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}
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static off_t
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zf_seek(struct open_file *f, off_t offset, int where)
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{
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struct z_file *zf = (struct z_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 + zf->zf_zstream.total_out;
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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 < zf->zf_zstream.total_out) {
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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 > zf->zf_zstream.total_out) {
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if (zf_read(f, discard, min(sizeof(discard), target - zf->zf_zstream.total_out), 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 (zf->zf_zstream.total_out);
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}
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static int
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zf_stat(struct open_file *f, struct stat *sb)
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{
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struct z_file *zf = (struct z_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(zf->zf_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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