409 lines
10 KiB
C
409 lines
10 KiB
C
/* $NetBSD: cread.c,v 1.2 1997/02/04 18:38:20 thorpej Exp $ */
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/*
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* Copyright (c) 1996
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* Matthias Drochner. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed for the NetBSD Project
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* by Matthias Drochner.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/* support for compressed bootfiles
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(only read)
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replaces open(), close(), read(), lseek().
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original libsa open(), close(), read(), lseek() are called
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as oopen(), oclose(), oread() resp. olseek().
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compression parts stripped from zlib:gzio.c
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*/
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/* gzio.c -- IO on .gz files
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* Copyright (C) 1995-1996 Jean-loup Gailly.
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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#include "stand.h"
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#include "../libz/zlib.h"
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#define EOF (-1) /* needed by compression code */
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#ifdef SAVE_MEMORY
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#define Z_BUFSIZE 1024
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#else
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#define Z_BUFSIZE 4096
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#endif
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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 struct sd {
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z_stream stream;
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int z_err; /* error code for last stream operation */
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int z_eof; /* set if end of input file */
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int fd;
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unsigned char *inbuf; /* input buffer */
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unsigned long crc; /* crc32 of uncompressed data */
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int transparent; /* 1 if input file is not a .gz file */
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} *ss[SOPEN_MAX];
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/*
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* compression utilities
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*/
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void *zcalloc (opaque, items, size)
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void *opaque;
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unsigned items;
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unsigned size;
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{
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return(alloc(items * size));
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}
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void zcfree (opaque, ptr)
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void *opaque;
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void *ptr;
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{
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free(ptr, 0); /* XXX works only with modified allocator */
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}
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void zmemcpy(dest, source, len)
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unsigned char *dest;
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unsigned char *source;
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unsigned int len;
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{
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bcopy(source, dest, len);
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}
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static int get_byte(s)
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struct sd *s;
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{
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if (s->z_eof) return EOF;
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if (s->stream.avail_in == 0) {
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errno = 0;
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s->stream.avail_in = oread(s->fd, s->inbuf, Z_BUFSIZE);
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if (s->stream.avail_in == 0) {
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s->z_eof = 1;
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if (errno) s->z_err = Z_ERRNO;
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return EOF;
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}
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s->stream.next_in = s->inbuf;
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}
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s->stream.avail_in--;
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return *(s->stream.next_in)++;
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}
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static unsigned long getLong (s)
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struct sd *s;
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{
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unsigned long x = (unsigned long)get_byte(s);
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int c;
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x += ((unsigned long)get_byte(s))<<8;
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x += ((unsigned long)get_byte(s))<<16;
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c = get_byte(s);
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if (c == EOF) s->z_err = Z_DATA_ERROR;
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x += ((unsigned long)c)<<24;
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return x;
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}
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static void check_header(s)
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struct sd *s;
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{
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int method; /* method byte */
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int flags; /* flags byte */
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unsigned int 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(s);
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if (c != gz_magic[len]) {
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s->transparent = 1;
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if (c != EOF) s->stream.avail_in++, s->stream.next_in--;
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s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END;
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return;
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}
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}
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method = get_byte(s);
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flags = get_byte(s);
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if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
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s->z_err = Z_DATA_ERROR;
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return;
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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(s);
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if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
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len = (unsigned int)get_byte(s);
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len += ((unsigned int)get_byte(s))<<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(s) != EOF) ;
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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(s)) != 0 && c != EOF) ;
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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(s)) != 0 && c != EOF) ;
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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++) (void)get_byte(s);
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}
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s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
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}
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/*
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* new open(), close(), read(), lseek()
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*/
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int
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open(fname, mode)
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const char *fname;
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int mode;
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{
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int fd;
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struct sd *s = 0;
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if(((fd = oopen(fname, mode)) == -1)
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|| (mode != 0)) /* compression only for read */
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return(fd);
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ss[fd] = s = alloc(sizeof(struct sd));
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if(!s) goto errout;
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bzero(s, sizeof(struct sd));
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if(inflateInit2(&(s->stream), -15) != Z_OK)
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goto errout;
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s->stream.next_in = s->inbuf = (unsigned char*)alloc(Z_BUFSIZE);
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if(!s->inbuf) {
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inflateEnd(&(s->stream));
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goto errout;
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}
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s->fd = fd;
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check_header(s); /* skip the .gz header */
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return(fd);
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errout:
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if(s) free(s, sizeof(struct sd));
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oclose(fd);
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return(-1);
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}
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int
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close(fd)
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int fd;
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{
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struct open_file *f;
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struct sd *s;
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if ((unsigned)fd >= SOPEN_MAX) {
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errno = EBADF;
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return (-1);
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}
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f = &files[fd];
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if(!(f->f_flags & F_READ))
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return(oclose(fd));
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s = ss[fd];
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inflateEnd(&(s->stream));
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free(s->inbuf, Z_BUFSIZE);
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free(s, sizeof(struct sd));
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return(oclose(fd));
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}
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ssize_t
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read(fd, buf, len)
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int fd;
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void *buf;
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size_t len;
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{
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struct sd *s;
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unsigned char *start = buf; /* starting point for crc computation */
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s = ss[fd];
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if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
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if (s->z_err == Z_STREAM_END) return 0; /* EOF */
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s->stream.next_out = buf;
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s->stream.avail_out = len;
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while (s->stream.avail_out != 0) {
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if (s->transparent) {
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/* Copy first the lookahead bytes: */
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unsigned int n = s->stream.avail_in;
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if (n > s->stream.avail_out) n = s->stream.avail_out;
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if (n > 0) {
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zmemcpy(s->stream.next_out, s->stream.next_in, n);
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s->stream.next_out += n;
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s->stream.next_in += n;
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s->stream.avail_out -= n;
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s->stream.avail_in -= n;
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}
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if (s->stream.avail_out > 0) {
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s->stream.avail_out -= oread(s->fd, s->stream.next_out, s->stream.avail_out);
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}
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return (int)(len - s->stream.avail_out);
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}
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if (s->stream.avail_in == 0 && !s->z_eof) {
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errno = 0;
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s->stream.avail_in = oread(fd, s->inbuf, Z_BUFSIZE);
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if (s->stream.avail_in == 0) {
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s->z_eof = 1;
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if (errno) {
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s->z_err = Z_ERRNO;
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break;
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}
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}
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s->stream.next_in = s->inbuf;
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}
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s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
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if (s->z_err == Z_STREAM_END) {
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/* Check CRC and original size */
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s->crc = crc32(s->crc, start, (unsigned int)(s->stream.next_out - start));
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start = s->stream.next_out;
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if (getLong(s) != s->crc || getLong(s) != s->stream.total_out) {
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s->z_err = Z_DATA_ERROR;
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} else {
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/* Check for concatenated .gz files: */
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check_header(s);
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if (s->z_err == Z_OK) {
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inflateReset(&(s->stream));
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s->crc = crc32(0L, Z_NULL, 0);
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}
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}
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}
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if (s->z_err != Z_OK || s->z_eof) break;
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}
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s->crc = crc32(s->crc, start, (unsigned int)(s->stream.next_out - start));
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return (int)(len - s->stream.avail_out);
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}
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off_t
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lseek(fd, offset, where)
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int fd;
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off_t offset;
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int where;
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{
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register struct open_file *f;
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struct sd *s;
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if ((unsigned)fd >= SOPEN_MAX) {
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errno = EBADF;
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return (-1);
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}
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f = &files[fd];;
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if(!(f->f_flags & F_READ))
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return(olseek(fd, offset, where));
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s = ss[fd];
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if(s->transparent) {
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off_t res = olseek(fd, offset, where);
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if(res != (off_t)-1) {
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/* make sure the lookahead buffer is invalid */
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s->stream.avail_in = 0;
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}
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return(res);
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}
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switch(where) {
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case SEEK_CUR:
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offset += s->stream.total_out;
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case SEEK_SET:
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/* if seek backwards, simply start from
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the beginning */
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if(offset < s->stream.total_out) {
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off_t res;
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void *sav_inbuf;
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res = olseek(fd, 0, SEEK_SET);
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if(res == (off_t)-1)
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return(res);
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/* ??? perhaps fallback to close / open */
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inflateEnd(&(s->stream));
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sav_inbuf = s->inbuf; /* don't allocate again */
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bzero(s, sizeof(struct sd)); /* this resets total_out to 0! */
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inflateInit2(&(s->stream), -15);
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s->stream.next_in = s->inbuf = sav_inbuf;
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s->fd = fd;
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check_header(s); /* skip the .gz header */
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}
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/* to seek forwards, throw away data */
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if(offset > s->stream.total_out) {
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off_t toskip = offset - s->stream.total_out;
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while(toskip > 0) {
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#define DUMMYBUFSIZE 256
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char dummybuf[DUMMYBUFSIZE];
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off_t len = toskip;
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if(len > DUMMYBUFSIZE) len = DUMMYBUFSIZE;
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if(read(fd, dummybuf, len) != len) {
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errno = EOFFSET;
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return((off_t)-1);
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}
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toskip -= len;
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}
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}
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#ifdef DEBUG
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if(offset != s->stream.total_out)
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panic("lseek compressed");
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#endif
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return(offset);
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case SEEK_END:
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errno = EOFFSET;
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break;
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default:
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errno = EINVAL;
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}
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return((off_t)-1);
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}
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