decompress.c revision 342440ec94087b8c751c580ab9ed6c693d31d418
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Decompression module for stand alone file systems.
*/
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/vnode.h>
#include <sys/bootvfs.h>
#include <sys/filep.h>
#include <zmod/zlib.h>
#ifdef _BOOT
#include "../common/util.h"
#else
#include <sys/sunddi.h>
#endif
#define MAX_DECOMP_BUFS 8
#define GZIP_ID_BYTE_1 0x1f
#define GZIP_ID_BYTE_2 0x8b
#define GZIP_CM_DEFLATE 0x08
#define SEEKBUFSIZE 8192
extern void prom_printf(const char *fmt, ...);
#ifdef _BOOT
#define dprintf if (cf_debug) prom_printf
#else
#define dprintf if (cf_debug) prom_printf
#endif
extern int bootrd_debug;
extern void *bkmem_alloc(size_t);
extern void bkmem_free(void *, size_t);
caddr_t scratch_bufs[MAX_DECOMP_BUFS]; /* array of free scratch mem bufs */
int decomp_bufcnt; /* total no, of allocated decomp bufs */
int free_dcomp_bufs; /* no. of free decomp bufs */
char seek_scrbuf[SEEKBUFSIZE]; /* buffer for seeking */
int cf_debug = 0; /* non-zero enables debug prints */
void *
cf_alloc(void *opaque, unsigned int items, unsigned int size)
{
fileid_t *filep;
unsigned int nbytes;
caddr_t ptr;
filep = (fileid_t *)opaque;
nbytes = roundup(items * size, sizeof (long));
if (nbytes > (DECOMP_BUFSIZE - filep->fi_dcscrused)) {
ptr = bkmem_alloc(nbytes);
} else {
ptr = &filep->fi_dcscrbuf[filep->fi_dcscrused];
filep->fi_dcscrused += nbytes;
}
bzero(ptr, nbytes);
return (ptr);
}
/*
* Decompression scratch memory free routine, does nothing since we free
* the entire scratch area all at once on file close.
*/
/* ARGSUSED */
void
cf_free(void *opaque, void *addr)
{
}
/*
* Read the first block of the file described by filep and determine if
* the file is gzip-compressed. If so, the compressed flag will be set
* in the fileid_t struct pointed to by filep and it will be initialized
* for doing decompression on reads to the file.
*/
int
cf_check_compressed(fileid_t *filep)
{
unsigned char *filebytes;
z_stream *zsp;
/*
* checking for a dcfs compressed file first would involve:
*
* if (filep->fi_inode->i_cflags & ICOMPRESS)
* filep->fi_flags |= FI_COMPRESSED;
*/
/*
* If the file is not long enough to check for a
* decompression header then return not compressed.
*/
if (filep->fi_inode->i_size < 3)
return (0);
filep->fi_offset = 0;
if ((filep->fi_getblock)(filep) == -1)
return (-1);
filep->fi_offset = 0;
filep->fi_count = 0;
filep->fi_cfoff = 0;
filebytes = (unsigned char *)filep->fi_memp;
if (filebytes[0] != GZIP_ID_BYTE_1 ||
filebytes[1] != GZIP_ID_BYTE_2 ||
filebytes[2] != GZIP_CM_DEFLATE)
return (0); /* not compressed */
filep->fi_flags |= FI_COMPRESSED;
dprintf("file %s is compressed\n", filep->fi_path);
/*
* Allocate decompress scratch buffer
*/
if (free_dcomp_bufs) {
filep->fi_dcscrbuf = scratch_bufs[--free_dcomp_bufs];
} else {
filep->fi_dcscrbuf = bkmem_alloc(DECOMP_BUFSIZE);
decomp_bufcnt++;
}
filep->fi_dcscrused = 0;
zsp = bkmem_alloc(sizeof (*zsp));
filep->fi_dcstream = zsp;
/*
* Initialize the decompression stream. Adding 16 to the window size
* indicates that zlib should expect a gzip header.
*/
bzero(zsp, sizeof (*zsp));
zsp->opaque = filep;
zsp->zalloc = cf_alloc;
zsp->zfree = cf_free;
zsp->avail_in = 0;
zsp->next_in = NULL;
zsp->avail_out = 0;
zsp->next_out = NULL;
if (inflateInit2(zsp, MAX_WBITS | 0x20) != Z_OK) {
dprintf("inflateInit2() failed\n");
return (-1);
}
return (0);
}
/*
* If the file described by fileid_t struct at *filep is compressed
* free any resources associated with the decompression. (decompression
* buffer, etc.).
*/
void
cf_close(fileid_t *filep)
{
if ((filep->fi_flags & FI_COMPRESSED) == 0)
return;
dprintf("cf_close: %s\n", filep->fi_path);
(void) inflateEnd(filep->fi_dcstream);
bkmem_free(filep->fi_dcstream, sizeof (z_stream));
if (free_dcomp_bufs == MAX_DECOMP_BUFS) {
bkmem_free(filep->fi_dcscrbuf, DECOMP_BUFSIZE);
} else {
scratch_bufs[free_dcomp_bufs++] = filep->fi_dcscrbuf;
}
}
void
cf_rewind(fileid_t *filep)
{
z_stream *zsp;
dprintf("cf_rewind: %s\n", filep->fi_path);
zsp = filep->fi_dcstream;
zsp->avail_in = 0;
zsp->next_in = NULL;
(void) inflateReset(zsp);
filep->fi_cfoff = 0;
}
#define FLG_FHCRC 0x02 /* crc field present */
#define FLG_FEXTRA 0x04 /* "extra" field present */
#define FLG_FNAME 0x08 /* file name field present */
#define FLG_FCOMMENT 0x10 /* comment field present */
/*
* Read at the current uncompressed offset from the compressed file described
* by *filep. Will return decompressed data.
*/
int
cf_read(fileid_t *filep, caddr_t buf, size_t count)
{
z_stream *zsp;
struct inode *ip;
int err = Z_OK;
int infbytes;
off_t soff;
caddr_t smemp;
dprintf("cf_read: %s ", filep->fi_path);
dprintf("%lx bytes\n", count);
zsp = filep->fi_dcstream;
ip = filep->fi_inode;
dprintf(" reading at offset %lx\n", zsp->total_out);
zsp->next_out = (unsigned char *)buf;
zsp->avail_out = count;
while (zsp->avail_out != 0) {
if (zsp->avail_in == 0 && filep->fi_cfoff < ip->i_size) {
/*
* read a block of the file to inflate
*/
soff = filep->fi_offset;
smemp = filep->fi_memp;
filep->fi_memp = NULL;
filep->fi_offset = filep->fi_cfoff;
filep->fi_count = 0;
if ((*filep->fi_getblock)(filep) == -1)
return (-1);
filep->fi_offset = soff;
zsp->next_in = (unsigned char *)filep->fi_memp;
zsp->avail_in = filep->fi_count;
filep->fi_memp = smemp;
filep->fi_cfoff += filep->fi_count;
}
infbytes = zsp->avail_out;
dprintf("attempting inflate of %x bytes to buf at: %lx\n",
zsp->avail_out, (unsigned long)zsp->next_out);
err = inflate(zsp, Z_NO_FLUSH);
infbytes -= zsp->avail_out;
dprintf("inflated %x bytes, errcode=%d\n", infbytes, err);
/*
* break out if we hit end of the compressed file
* or the end of the compressed byte stream
*/
if (filep->fi_cfoff >= ip->i_size || err == Z_STREAM_END)
break;
}
dprintf("cf_read: returned %lx bytes\n", count - zsp->avail_out);
return (count - zsp->avail_out);
}
/*
* Seek to the location specified by addr
*/
void
cf_seek(fileid_t *filep, off_t addr, int whence)
{
z_stream *zsp;
int readsz;
dprintf("cf_seek: %s ", filep->fi_path);
dprintf("to %lx\n", addr);
zsp = filep->fi_dcstream;
if (whence == SEEK_CUR)
addr += zsp->total_out;
/*
* To seek backwards, must rewind and seek forwards
*/
if (addr < zsp->total_out) {
cf_rewind(filep);
filep->fi_offset = 0;
} else {
addr -= zsp->total_out;
}
while (addr > 0) {
readsz = MIN(addr, SEEKBUFSIZE);
(void) cf_read(filep, seek_scrbuf, readsz);
addr -= readsz;
}
}