407 lines
12 KiB
C
407 lines
12 KiB
C
/*
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* $Id: kern_gzio.c,v 1.6 2008-10-18 22:54:45 lbazinet Exp $
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*
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* core_gzip.c -- gzip routines used in compressing user process cores
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*
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* This file is derived from src/lib/libz/gzio.c in FreeBSD.
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*/
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/* gzio.c -- IO on .gz files
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* Copyright (C) 1995-1998 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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*/
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/* @(#) $FreeBSD$ */
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/vnode.h>
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#include <sys/syslog.h>
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#include <sys/endian.h>
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#include <net/zutil.h>
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#include <sys/libkern.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#define GZ_HEADER_LEN 10
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#ifndef Z_BUFSIZE
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# ifdef MAXSEG_64K
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# define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
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# else
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# define Z_BUFSIZE 16384
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# endif
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#endif
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#ifndef Z_PRINTF_BUFSIZE
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# define Z_PRINTF_BUFSIZE 4096
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#endif
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#define ALLOC(size) malloc(size, M_TEMP, M_WAITOK | M_ZERO)
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#define TRYFREE(p) {if (p) free(p, M_TEMP);}
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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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typedef struct gz_stream {
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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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struct vnode *file; /* vnode pointer of .gz file */
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Byte *inbuf; /* input buffer */
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Byte *outbuf; /* output buffer */
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uLong crc; /* crc32 of uncompressed data */
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char *msg; /* error message */
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char *path; /* path name for debugging only */
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int transparent; /* 1 if input file is not a .gz file */
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char mode; /* 'w' or 'r' */
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long startpos; /* start of compressed data in file (header skipped) */
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off_t outoff; /* current offset in output file */
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int flags;
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} gz_stream;
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local int do_flush OF((gzFile file, int flush));
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local int destroy OF((gz_stream *s));
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local void putU32 OF((gz_stream *file, uint32_t x));
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local void *gz_alloc OF((void *notused, u_int items, u_int size));
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local void gz_free OF((void *notused, void *ptr));
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/* ===========================================================================
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Opens a gzip (.gz) file for reading or writing. The mode parameter
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is as in fopen ("rb" or "wb"). The file is given either by file descriptor
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or path name (if fd == -1).
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gz_open return NULL if the file could not be opened or if there was
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insufficient memory to allocate the (de)compression state; errno
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can be checked to distinguish the two cases (if errno is zero, the
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zlib error is Z_MEM_ERROR).
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*/
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gzFile gz_open (path, mode, vp)
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const char *path;
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const char *mode;
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struct vnode *vp;
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{
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int err;
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int level = Z_DEFAULT_COMPRESSION; /* compression level */
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int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
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const char *p = mode;
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gz_stream *s;
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char fmode[80]; /* copy of mode, without the compression level */
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char *m = fmode;
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int resid;
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int error;
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char buf[GZ_HEADER_LEN + 1];
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if (!path || !mode) return Z_NULL;
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s = (gz_stream *)ALLOC(sizeof(gz_stream));
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if (!s) return Z_NULL;
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s->stream.zalloc = (alloc_func)gz_alloc;
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s->stream.zfree = (free_func)gz_free;
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s->stream.opaque = (voidpf)0;
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s->stream.next_in = s->inbuf = Z_NULL;
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s->stream.next_out = s->outbuf = Z_NULL;
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s->stream.avail_in = s->stream.avail_out = 0;
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s->file = NULL;
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s->z_err = Z_OK;
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s->z_eof = 0;
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s->crc = 0;
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s->msg = NULL;
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s->transparent = 0;
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s->outoff = 0;
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s->flags = 0;
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s->path = (char*)ALLOC(strlen(path)+1);
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if (s->path == NULL) {
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return destroy(s), (gzFile)Z_NULL;
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}
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strcpy(s->path, path); /* do this early for debugging */
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s->mode = '\0';
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do {
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if (*p == 'r') s->mode = 'r';
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if (*p == 'w' || *p == 'a') s->mode = 'w';
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if (*p >= '0' && *p <= '9') {
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level = *p - '0';
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} else if (*p == 'f') {
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strategy = Z_FILTERED;
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} else if (*p == 'h') {
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strategy = Z_HUFFMAN_ONLY;
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} else {
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*m++ = *p; /* copy the mode */
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}
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} while (*p++ && m != fmode + sizeof(fmode));
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if (s->mode != 'w') {
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log(LOG_ERR, "gz_open: mode is not w (%c)\n", s->mode);
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return destroy(s), (gzFile)Z_NULL;
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}
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err = deflateInit2(&(s->stream), level,
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Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
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/* windowBits is passed < 0 to suppress zlib header */
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s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
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if (err != Z_OK || s->outbuf == Z_NULL) {
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return destroy(s), (gzFile)Z_NULL;
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}
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s->stream.avail_out = Z_BUFSIZE;
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s->file = vp;
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/* Write a very simple .gz header:
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*/
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snprintf(buf, sizeof(buf), "%c%c%c%c%c%c%c%c%c%c", gz_magic[0],
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gz_magic[1], Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/,
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0 /*xflags*/, OS_CODE);
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if ((error = vn_rdwr(UIO_WRITE, s->file, buf, GZ_HEADER_LEN, s->outoff,
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UIO_SYSSPACE, IO_UNIT, curproc->p_ucred,
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NOCRED, &resid, curthread))) {
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s->outoff += GZ_HEADER_LEN - resid;
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return destroy(s), (gzFile)Z_NULL;
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}
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s->outoff += GZ_HEADER_LEN;
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s->startpos = 10L;
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return (gzFile)s;
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}
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/* ===========================================================================
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* Cleanup then free the given gz_stream. Return a zlib error code.
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Try freeing in the reverse order of allocations.
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*/
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local int destroy (s)
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gz_stream *s;
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{
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int err = Z_OK;
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if (!s) return Z_STREAM_ERROR;
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TRYFREE(s->msg);
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if (s->stream.state != NULL) {
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if (s->mode == 'w') {
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err = deflateEnd(&(s->stream));
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}
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}
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if (s->z_err < 0) err = s->z_err;
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TRYFREE(s->inbuf);
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TRYFREE(s->outbuf);
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TRYFREE(s->path);
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TRYFREE(s);
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return err;
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}
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/* ===========================================================================
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Writes the given number of uncompressed bytes into the compressed file.
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gzwrite returns the number of bytes actually written (0 in case of error).
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*/
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int ZEXPORT gzwrite (file, buf, len)
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gzFile file;
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const voidp buf;
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unsigned len;
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{
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gz_stream *s = (gz_stream*)file;
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off_t curoff;
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size_t resid;
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int error;
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int vfslocked;
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if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
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s->stream.next_in = (Bytef*)buf;
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s->stream.avail_in = len;
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curoff = s->outoff;
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while (s->stream.avail_in != 0) {
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if (s->stream.avail_out == 0) {
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s->stream.next_out = s->outbuf;
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vfslocked = VFS_LOCK_GIANT(s->file->v_mount);
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error = vn_rdwr_inchunks(UIO_WRITE, s->file, s->outbuf, Z_BUFSIZE,
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curoff, UIO_SYSSPACE, IO_UNIT,
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curproc->p_ucred, NOCRED, &resid, curthread);
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VFS_UNLOCK_GIANT(vfslocked);
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if (error) {
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log(LOG_ERR, "gzwrite: vn_rdwr return %d\n", error);
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curoff += Z_BUFSIZE - resid;
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s->z_err = Z_ERRNO;
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break;
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}
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curoff += Z_BUFSIZE;
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s->stream.avail_out = Z_BUFSIZE;
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}
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s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
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if (s->z_err != Z_OK) {
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log(LOG_ERR,
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"gzwrite: deflate returned error %d\n", s->z_err);
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break;
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}
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}
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s->crc = ~crc32_raw(buf, len, ~s->crc);
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s->outoff = curoff;
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return (int)(len - s->stream.avail_in);
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}
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/* ===========================================================================
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Flushes all pending output into the compressed file. The parameter
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flush is as in the deflate() function.
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*/
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local int do_flush (file, flush)
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gzFile file;
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int flush;
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{
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uInt len;
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int done = 0;
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gz_stream *s = (gz_stream*)file;
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off_t curoff = s->outoff;
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size_t resid;
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int vfslocked = 0;
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int error;
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if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
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if (s->stream.avail_in) {
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log(LOG_WARNING, "do_flush: avail_in non-zero on entry\n");
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}
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s->stream.avail_in = 0; /* should be zero already anyway */
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for (;;) {
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len = Z_BUFSIZE - s->stream.avail_out;
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if (len != 0) {
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vfslocked = VFS_LOCK_GIANT(s->file->v_mount);
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error = vn_rdwr_inchunks(UIO_WRITE, s->file, s->outbuf, len, curoff,
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UIO_SYSSPACE, IO_UNIT, curproc->p_ucred,
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NOCRED, &resid, curthread);
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VFS_UNLOCK_GIANT(vfslocked);
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if (error) {
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s->z_err = Z_ERRNO;
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s->outoff = curoff + len - resid;
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return Z_ERRNO;
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}
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s->stream.next_out = s->outbuf;
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s->stream.avail_out = Z_BUFSIZE;
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curoff += len;
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}
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if (done) break;
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s->z_err = deflate(&(s->stream), flush);
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/* Ignore the second of two consecutive flushes: */
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if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
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/* deflate has finished flushing only when it hasn't used up
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* all the available space in the output buffer:
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*/
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done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
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if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
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}
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s->outoff = curoff;
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return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
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}
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int ZEXPORT gzflush (file, flush)
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gzFile file;
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int flush;
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{
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gz_stream *s = (gz_stream*)file;
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int err = do_flush (file, flush);
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if (err) return err;
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return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
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}
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/* ===========================================================================
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Outputs a long in LSB order to the given file
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*/
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local void putU32 (s, x)
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gz_stream *s;
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uint32_t x;
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{
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uint32_t xx;
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off_t curoff = s->outoff;
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int resid;
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#if BYTE_ORDER == BIG_ENDIAN
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xx = bswap32(x);
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#else
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xx = x;
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#endif
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vn_rdwr(UIO_WRITE, s->file, (caddr_t)&xx, sizeof(xx), curoff,
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UIO_SYSSPACE, IO_UNIT, curproc->p_ucred,
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NOCRED, &resid, curthread);
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s->outoff += sizeof(xx) - resid;
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}
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/* ===========================================================================
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Flushes all pending output if necessary, closes the compressed file
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and deallocates all the (de)compression state.
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*/
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int ZEXPORT gzclose (file)
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gzFile file;
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{
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int err;
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gz_stream *s = (gz_stream*)file;
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if (s == NULL) return Z_STREAM_ERROR;
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if (s->mode == 'w') {
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err = do_flush (file, Z_FINISH);
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if (err != Z_OK) {
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log(LOG_ERR, "gzclose: do_flush failed (err %d)\n", err);
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return destroy((gz_stream*)file);
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}
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#if 0
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printf("gzclose: putting crc: %lld total: %lld\n",
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(long long)s->crc, (long long)s->stream.total_in);
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printf("sizeof uLong = %d\n", (int)sizeof(uLong));
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#endif
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putU32 (s, s->crc);
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putU32 (s, (uint32_t) s->stream.total_in);
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}
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return destroy((gz_stream*)file);
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}
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/*
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* Space allocation and freeing routines for use by zlib routines when called
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* from gzip modules.
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*/
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static void *
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gz_alloc(void *notused __unused, u_int items, u_int size)
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{
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void *ptr;
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MALLOC(ptr, void *, items * size, M_TEMP, M_NOWAIT | M_ZERO);
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return ptr;
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}
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static void
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gz_free(void *opaque __unused, void *ptr)
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{
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FREE(ptr, M_TEMP);
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}
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