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 $
27 * $DragonFly: src/lib/libstand/gzipfs.c,v 1.1 2003/11/10 06:14:44 dillon Exp $
36 #define Z_BUFSIZE 2048 /* XXX larger? */
42 char zf_buf[Z_BUFSIZE];
45 static int zf_fill(struct z_file *z);
46 static int zf_open(const char *path, struct open_file *f);
47 static int zf_close(struct open_file *f);
48 static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
49 static off_t zf_seek(struct open_file *f, off_t offset, int where);
50 static int zf_stat(struct open_file *f, struct stat *sb);
52 struct fs_ops gzipfs_fsops = {
65 calloc(int items, size_t size)
67 return(malloc(items * size));
72 zf_fill(struct z_file *zf)
77 req = Z_BUFSIZE - zf->zf_zstream.avail_in;
82 /* move old data to bottom of buffer */
84 bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
86 /* read to fill buffer and update availibility data */
87 result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
88 zf->zf_zstream.next_in = zf->zf_buf;
90 zf->zf_zstream.avail_in += result;
96 * Adapted from get_byte/check_header in libz
98 * Returns 0 if the header is OK, nonzero if not.
101 get_byte(struct z_file *zf)
103 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
105 zf->zf_zstream.avail_in--;
106 return(*(zf->zf_zstream.next_in)++);
109 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
112 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
113 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
114 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
115 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
116 #define COMMENT 0x10 /* bit 4 set: file comment present */
117 #define RESERVED 0xE0 /* bits 5..7: reserved */
120 check_header(struct z_file *zf)
122 int method; /* method byte */
123 int flags; /* flags byte */
127 /* Check the gzip magic header */
128 for (len = 0; len < 2; len++) {
130 if (c != gz_magic[len]) {
134 method = get_byte(zf);
135 flags = get_byte(zf);
136 if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
140 /* Discard time, xflags and OS code: */
141 for (len = 0; len < 6; len++) (void)get_byte(zf);
143 if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
144 len = (uInt)get_byte(zf);
145 len += ((uInt)get_byte(zf))<<8;
146 /* len is garbage if EOF but the loop below will quit anyway */
147 while (len-- != 0 && get_byte(zf) != -1) ;
149 if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
150 while ((c = get_byte(zf)) != 0 && c != -1) ;
152 if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
153 while ((c = get_byte(zf)) != 0 && c != -1) ;
155 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
156 for (len = 0; len < 2; len++) c = get_byte(zf);
158 /* if there's data left, we're in business */
159 return((c == -1) ? 1 : 0);
163 zf_open(const char *fname, struct open_file *f)
172 /* Have to be in "just read it" mode */
173 if (f->f_flags != F_READ)
176 /* If the name already ends in .gz or .bz2, ignore it */
177 if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
178 || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
181 /* Construct new name */
182 zfname = malloc(strlen(fname) + 4);
185 sprintf(zfname, "%s.gz", fname);
186 /* Try to open the compressed datafile */
187 rawfd = open(zfname, O_RDONLY);
192 if (fstat(rawfd, &sb) < 0) {
193 printf("zf_open: stat failed\n");
197 if (!S_ISREG(sb.st_mode)) {
198 printf("zf_open: not a file\n");
200 return(EISDIR); /* best guess */
203 /* Allocate a z_file structure, populate it */
204 zf = malloc(sizeof(struct z_file));
207 bzero(zf, sizeof(struct z_file));
208 zf->zf_rawfd = rawfd;
210 /* Verify that the file is gzipped (XXX why do this afterwards?) */
211 if (check_header(zf)) {
213 inflateEnd(&(zf->zf_zstream));
218 /* Initialise the inflation engine */
219 if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
220 printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
226 /* Looks OK, we'll take it */
232 zf_close(struct open_file *f)
234 struct z_file *zf = (struct z_file *)f->f_fsdata;
238 inflateEnd(&(zf->zf_zstream));
246 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
248 struct z_file *zf = (struct z_file *)f->f_fsdata;
251 zf->zf_zstream.next_out = buf; /* where and how much */
252 zf->zf_zstream.avail_out = size;
254 while (zf->zf_zstream.avail_out) {
255 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
256 printf("zf_read: fill error\n");
259 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
260 printf("zf_read: unexpected EOF\n");
264 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
265 if (error == Z_STREAM_END) { /* EOF, all done */
268 if (error != Z_OK) { /* argh, decompression error */
269 printf("inflate: %s\n", zf->zf_zstream.msg);
275 *resid = zf->zf_zstream.avail_out;
280 zf_seek(struct open_file *f, off_t offset, int where)
282 struct z_file *zf = (struct z_file *)f->f_fsdata;
291 target = offset + zf->zf_zstream.total_out;
297 /* Can we get there from here? */
298 if (target < zf->zf_zstream.total_out) {
303 /* skip forwards if required */
304 while (target > zf->zf_zstream.total_out) {
305 if (zf_read(f, discard, min(sizeof(discard), target - zf->zf_zstream.total_out), NULL) == -1)
308 /* This is where we are (be honest if we overshot) */
309 return (zf->zf_zstream.total_out);
314 zf_stat(struct open_file *f, struct stat *sb)
316 struct z_file *zf = (struct z_file *)f->f_fsdata;
319 /* stat as normal, but indicate that size is unknown */
320 if ((result = fstat(zf->zf_rawfd, sb)) == 0)