2 * Copyright (c) 1998 Michael Smith.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/lib/libstand/gzipfs.c,v 1.11 2002/12/19 19:34:58 jake Exp $
35 #define Z_BUFSIZE 2048 /* XXX larger? */
41 char zf_buf
[Z_BUFSIZE
];
44 static int zf_fill(struct z_file
*z
);
45 static int zf_open(const char *path
, struct open_file
*f
);
46 static int zf_close(struct open_file
*f
);
47 static int zf_read(struct open_file
*f
, void *buf
, size_t size
, size_t *resid
);
48 static off_t
zf_seek(struct open_file
*f
, off_t offset
, int where
);
49 static int zf_stat(struct open_file
*f
, struct stat
*sb
);
51 struct fs_ops gzipfs_fsops
= {
63 zf_fill(struct z_file
*zf
)
68 req
= Z_BUFSIZE
- zf
->zf_zstream
.avail_in
;
73 /* move old data to bottom of buffer */
75 bcopy(zf
->zf_buf
+ req
, zf
->zf_buf
, Z_BUFSIZE
- req
);
77 /* read to fill buffer and update availibility data */
78 result
= read(zf
->zf_rawfd
, zf
->zf_buf
+ zf
->zf_zstream
.avail_in
, req
);
79 zf
->zf_zstream
.next_in
= zf
->zf_buf
;
81 zf
->zf_zstream
.avail_in
+= result
;
87 * Adapted from get_byte/check_header in libz
89 * Returns 0 if the header is OK, nonzero if not.
92 get_byte(struct z_file
*zf
)
94 if ((zf
->zf_zstream
.avail_in
== 0) && (zf_fill(zf
) == -1))
96 zf
->zf_zstream
.avail_in
--;
97 return(*(zf
->zf_zstream
.next_in
)++);
100 static int gz_magic
[2] = {0x1f, 0x8b}; /* gzip magic header */
103 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
104 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
105 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
106 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
107 #define COMMENT 0x10 /* bit 4 set: file comment present */
108 #define RESERVED 0xE0 /* bits 5..7: reserved */
111 check_header(struct z_file
*zf
)
113 int method
; /* method byte */
114 int flags
; /* flags byte */
118 /* Check the gzip magic header */
119 for (len
= 0; len
< 2; len
++) {
121 if (c
!= gz_magic
[len
]) {
125 method
= get_byte(zf
);
126 flags
= get_byte(zf
);
127 if (method
!= Z_DEFLATED
|| (flags
& RESERVED
) != 0) {
131 /* Discard time, xflags and OS code: */
132 for (len
= 0; len
< 6; len
++) (void)get_byte(zf
);
134 if ((flags
& EXTRA_FIELD
) != 0) { /* skip the extra field */
135 len
= (uInt
)get_byte(zf
);
136 len
+= ((uInt
)get_byte(zf
))<<8;
137 /* len is garbage if EOF but the loop below will quit anyway */
138 while (len
-- != 0 && get_byte(zf
) != -1) ;
140 if ((flags
& ORIG_NAME
) != 0) { /* skip the original file name */
141 while ((c
= get_byte(zf
)) != 0 && c
!= -1) ;
143 if ((flags
& COMMENT
) != 0) { /* skip the .gz file comment */
144 while ((c
= get_byte(zf
)) != 0 && c
!= -1) ;
146 if ((flags
& HEAD_CRC
) != 0) { /* skip the header crc */
147 for (len
= 0; len
< 2; len
++) c
= get_byte(zf
);
149 /* if there's data left, we're in business */
150 return((c
== -1) ? 1 : 0);
154 zf_open(const char *fname
, struct open_file
*f
)
163 /* Have to be in "just read it" mode */
164 if ((f
->f_flags
& (F_READ
| F_WRITE
)) != F_READ
)
167 /* If the name already ends in .gz or .bz2, ignore it */
168 if ((cp
= strrchr(fname
, '.')) && (!strcmp(cp
, ".gz")
169 || !strcmp(cp
, ".bz2") || !strcmp(cp
, ".split")))
172 /* Construct new name */
173 zfname
= malloc(strlen(fname
) + 4);
176 sprintf(zfname
, "%s.gz", fname
);
178 /* Try to open the compressed datafile */
179 rawfd
= open(zfname
, O_RDONLY
);
184 if (fstat(rawfd
, &sb
) < 0) {
185 printf("zf_open: stat failed\n");
189 if (!S_ISREG(sb
.st_mode
)) {
190 printf("zf_open: not a file\n");
192 return(EISDIR
); /* best guess */
195 /* Allocate a z_file structure, populate it */
196 zf
= malloc(sizeof(struct z_file
));
199 bzero(zf
, sizeof(struct z_file
));
200 zf
->zf_rawfd
= rawfd
;
202 /* Verify that the file is gzipped (XXX why do this afterwards?) */
203 if (check_header(zf
)) {
205 inflateEnd(&(zf
->zf_zstream
));
210 /* Initialise the inflation engine */
211 if ((error
= inflateInit2(&(zf
->zf_zstream
), -15)) != Z_OK
) {
212 printf("zf_open: inflateInit returned %d : %s\n", error
, zf
->zf_zstream
.msg
);
218 /* Looks OK, we'll take it */
224 zf_close(struct open_file
*f
)
226 struct z_file
*zf
= (struct z_file
*)f
->f_fsdata
;
230 inflateEnd(&(zf
->zf_zstream
));
238 zf_read(struct open_file
*f
, void *buf
, size_t size
, size_t *resid
)
240 struct z_file
*zf
= (struct z_file
*)f
->f_fsdata
;
243 zf
->zf_zstream
.next_out
= buf
; /* where and how much */
244 zf
->zf_zstream
.avail_out
= size
;
246 while (zf
->zf_zstream
.avail_out
) {
247 if ((zf
->zf_zstream
.avail_in
== 0) && (zf_fill(zf
) == -1)) {
248 printf("zf_read: fill error\n");
251 if (zf
->zf_zstream
.avail_in
== 0) { /* oops, unexpected EOF */
252 printf("zf_read: unexpected EOF\n");
256 error
= inflate(&zf
->zf_zstream
, Z_SYNC_FLUSH
); /* decompression pass */
257 if (error
== Z_STREAM_END
) { /* EOF, all done */
260 if (error
!= Z_OK
) { /* argh, decompression error */
261 printf("inflate: %s\n", zf
->zf_zstream
.msg
);
267 *resid
= zf
->zf_zstream
.avail_out
;
272 zf_seek(struct open_file
*f
, off_t offset
, int where
)
274 struct z_file
*zf
= (struct z_file
*)f
->f_fsdata
;
283 target
= offset
+ zf
->zf_zstream
.total_out
;
289 /* Can we get there from here? */
290 if (target
< zf
->zf_zstream
.total_out
) {
295 /* skip forwards if required */
296 while (target
> zf
->zf_zstream
.total_out
) {
297 if (zf_read(f
, discard
, min(sizeof(discard
), target
- zf
->zf_zstream
.total_out
), NULL
) == -1)
300 /* This is where we are (be honest if we overshot) */
301 return (zf
->zf_zstream
.total_out
);
305 zf_stat(struct open_file
*f
, struct stat
*sb
)
307 struct z_file
*zf
= (struct z_file
*)f
->f_fsdata
;
310 /* stat as normal, but indicate that size is unknown */
311 if ((result
= fstat(zf
->zf_rawfd
, sb
)) == 0)