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9.0 KiB

/*
* Copyright (c) 1998 Michael Smith.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "stand.h"
#include <sys/stat.h>
#include <string.h>
#include <zlib.h>
#define Z_BUFSIZE 2048 /* XXX larger? */
struct z_file
{
int zf_rawfd;
off_t zf_dataoffset;
z_stream zf_zstream;
unsigned char zf_buf[Z_BUFSIZE];
int zf_endseen;
};
static int zf_fill(struct z_file *z);
static int zf_open(const char *path, struct open_file *f);
static int zf_close(struct open_file *f);
static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t zf_seek(struct open_file *f, off_t offset, int where);
static int zf_stat(struct open_file *f, struct stat *sb);
struct fs_ops gzipfs_fsops = {
"zip",
zf_open,
zf_close,
zf_read,
null_write,
zf_seek,
zf_stat,
null_readdir
};
static int
zf_fill(struct z_file *zf)
{
int result;
int req;
req = Z_BUFSIZE - zf->zf_zstream.avail_in;
result = 0;
/* If we need more */
if (req > 0) {
/* move old data to bottom of buffer */
if (req < Z_BUFSIZE)
bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
/* read to fill buffer and update availibility data */
result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
zf->zf_zstream.next_in = zf->zf_buf;
if (result >= 0)
zf->zf_zstream.avail_in += result;
}
return(result);
}
/*
* Adapted from get_byte/check_header in libz
*
* Returns 0 if the header is OK, nonzero if not.
*/
static int
get_byte(struct z_file *zf, off_t *curoffp)
{
if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
return(-1);
zf->zf_zstream.avail_in--;
++*curoffp;
return(*(zf->zf_zstream.next_in)++);
}
static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define RESERVED 0xE0 /* bits 5..7: reserved */
static int
check_header(struct z_file *zf)
{
int method; /* method byte */
int flags; /* flags byte */
uInt len;
int c;
zf->zf_dataoffset = 0;
/* Check the gzip magic header */
for (len = 0; len < 2; len++) {
c = get_byte(zf, &zf->zf_dataoffset);
if (c != gz_magic[len]) {
return(1);
}
}
method = get_byte(zf, &zf->zf_dataoffset);
flags = get_byte(zf, &zf->zf_dataoffset);
if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
return(1);
}
/* Discard time, xflags and OS code: */
for (len = 0; len < 6; len++) (void)get_byte(zf, &zf->zf_dataoffset);
if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
len = (uInt)get_byte(zf, &zf->zf_dataoffset);
len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
/* len is garbage if EOF but the loop below will quit anyway */
while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1) ;
}
if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
}
if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
}
if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
for (len = 0; len < 2; len++) c = get_byte(zf, &zf->zf_dataoffset);
}
/* if there's data left, we're in business */
return((c == -1) ? 1 : 0);
}
static int
zf_open(const char *fname, struct open_file *f)
{
static char *zfname;
int rawfd;
struct z_file *zf;
char *cp;
int error;
struct stat sb;
/* Have to be in "just read it" mode */
if (f->f_flags != F_READ)
return(EPERM);
/* If the name already ends in .gz or .bz2, ignore it */
if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
|| !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
return(ENOENT);
/* Construct new name */
zfname = malloc(strlen(fname) + 4);
if (zfname == NULL)
return(ENOMEM);
sprintf(zfname, "%s.gz", fname);
/* Try to open the compressed datafile */
rawfd = open(zfname, O_RDONLY);
free(zfname);
if (rawfd == -1)
return(ENOENT);
if (fstat(rawfd, &sb) < 0) {
printf("zf_open: stat failed\n");
close(rawfd);
return(ENOENT);
}
if (!S_ISREG(sb.st_mode)) {
printf("zf_open: not a file\n");
close(rawfd);
return(EISDIR); /* best guess */
}
/* Allocate a z_file structure, populate it */
zf = malloc(sizeof(struct z_file));
if (zf == NULL)
return(ENOMEM);
bzero(zf, sizeof(struct z_file));
zf->zf_rawfd = rawfd;
/* Verify that the file is gzipped */
if (check_header(zf)) {
close(zf->zf_rawfd);
free(zf);
return(EFTYPE);
}
/* Initialise the inflation engine */
if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
close(zf->zf_rawfd);
free(zf);
return(EIO);
}
/* Looks OK, we'll take it */
f->f_fsdata = zf;
return(0);
}
static int
zf_close(struct open_file *f)
{
struct z_file *zf = (struct z_file *)f->f_fsdata;
inflateEnd(&(zf->zf_zstream));
close(zf->zf_rawfd);
free(zf);
return(0);
}
static int
zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
{
struct z_file *zf = (struct z_file *)f->f_fsdata;
int error;
zf->zf_zstream.next_out = buf; /* where and how much */
zf->zf_zstream.avail_out = size;
while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
printf("zf_read: fill error\n");
return(EIO);
}
if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
printf("zf_read: unexpected EOF\n");
if (zf->zf_zstream.avail_out == size)
return(EIO);
break;
}
error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
if (error == Z_STREAM_END) { /* EOF, all done */
zf->zf_endseen = 1;
break;
}
if (error != Z_OK) { /* argh, decompression error */
printf("inflate: %s\n", zf->zf_zstream.msg);
return(EIO);
}
}
if (resid != NULL)
*resid = zf->zf_zstream.avail_out;
return(0);
}
static int
zf_rewind(struct open_file *f)
{
struct z_file *zf = (struct z_file *)f->f_fsdata;
if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
return(-1);
zf->zf_zstream.avail_in = 0;
zf->zf_zstream.next_in = NULL;
zf->zf_endseen = 0;
(void)inflateReset(&zf->zf_zstream);
return(0);
}
static off_t
zf_seek(struct open_file *f, off_t offset, int where)
{
struct z_file *zf = (struct z_file *)f->f_fsdata;
off_t target;
char discard[16];
switch (where) {
case SEEK_SET:
target = offset;
break;
case SEEK_CUR:
target = offset + zf->zf_zstream.total_out;
break;
default:
errno = EINVAL;
return(-1);
}
/* rewind if required */
if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
return(-1);
/* skip forwards if required */
while (target > zf->zf_zstream.total_out) {
errno = zf_read(f, discard, min(sizeof(discard),
target - zf->zf_zstream.total_out), NULL);
if (errno)
return(-1);
/* Break out of loop if end of file has been reached. */
if (zf->zf_endseen)
break;
}
/* This is where we are (be honest if we overshot) */
return(zf->zf_zstream.total_out);
}
static int
zf_stat(struct open_file *f, struct stat *sb)
{
struct z_file *zf = (struct z_file *)f->f_fsdata;
int result;
/* stat as normal, but indicate that size is unknown */
if ((result = fstat(zf->zf_rawfd, sb)) == 0)
sb->st_size = -1;
return(result);
}