1 /*
2 * Copyright (c) 1998 Michael Smith.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 */
26
27 #include "stand.h"
28
29 #include <sys/stat.h>
30 #include <string.h>
31 #include <zlib.h>
32
33 #define Z_BUFSIZE 2048 /* XXX larger? */
34
35 struct z_file
36 {
37 int zf_rawfd;
38 off_t zf_dataoffset;
39 z_stream zf_zstream;
40 unsigned char zf_buf[Z_BUFSIZE];
41 int zf_endseen;
42 };
43
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);
50
51 struct fs_ops gzipfs_fsops = {
52 .fs_name = "zip",
53 .fs_flags = 0,
54 .fo_open = zf_open,
55 .fo_close = zf_close,
56 .fo_read = zf_read,
57 .fo_write = null_write,
58 .fo_seek = zf_seek,
59 .fo_stat = zf_stat,
60 .fo_readdir = null_readdir,
61 };
62
63 static int
zf_fill(struct z_file * zf)64 zf_fill(struct z_file *zf)
65 {
66 int result;
67 int req;
68
69 req = Z_BUFSIZE - zf->zf_zstream.avail_in;
70 result = 0;
71
72 /* If we need more */
73 if (req > 0) {
74 /* move old data to bottom of buffer */
75 if (req < Z_BUFSIZE)
76 bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
77
78 /* read to fill buffer and update availibility data */
79 result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
80 zf->zf_zstream.next_in = zf->zf_buf;
81 if (result >= 0)
82 zf->zf_zstream.avail_in += result;
83 }
84 return(result);
85 }
86
87 /*
88 * Adapted from get_byte/check_header in libz
89 *
90 * Returns 0 if the header is OK, nonzero if not.
91 */
92 static int
get_byte(struct z_file * zf,off_t * curoffp)93 get_byte(struct z_file *zf, off_t *curoffp)
94 {
95 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
96 return(-1);
97 zf->zf_zstream.avail_in--;
98 ++*curoffp;
99 return(*(zf->zf_zstream.next_in)++);
100 }
101
102 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
103
104 /* gzip flag byte */
105 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
106 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
107 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
108 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
109 #define COMMENT 0x10 /* bit 4 set: file comment present */
110 #define RESERVED 0xE0 /* bits 5..7: reserved */
111
112 static int
check_header(struct z_file * zf)113 check_header(struct z_file *zf)
114 {
115 int method; /* method byte */
116 int flags; /* flags byte */
117 uInt len;
118 int c;
119
120 zf->zf_dataoffset = 0;
121 /* Check the gzip magic header */
122 for (len = 0; len < 2; len++) {
123 c = get_byte(zf, &zf->zf_dataoffset);
124 if (c != gz_magic[len]) {
125 return(1);
126 }
127 }
128 method = get_byte(zf, &zf->zf_dataoffset);
129 flags = get_byte(zf, &zf->zf_dataoffset);
130 if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
131 return(1);
132 }
133
134 /* Discard time, xflags and OS code: */
135 for (len = 0; len < 6; len++) (void)get_byte(zf, &zf->zf_dataoffset);
136
137 if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
138 len = (uInt)get_byte(zf, &zf->zf_dataoffset);
139 len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
140 /* len is garbage if EOF but the loop below will quit anyway */
141 while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1) ;
142 }
143 if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
144 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
145 }
146 if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
147 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
148 }
149 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
150 for (len = 0; len < 2; len++) c = get_byte(zf, &zf->zf_dataoffset);
151 }
152 /* if there's data left, we're in business */
153 return((c == -1) ? 1 : 0);
154 }
155
156 static int
zf_open(const char * fname,struct open_file * f)157 zf_open(const char *fname, struct open_file *f)
158 {
159 static char *zfname;
160 int rawfd;
161 struct z_file *zf;
162 char *cp;
163 int error;
164 struct stat sb;
165
166 /* Have to be in "just read it" mode */
167 if (f->f_flags != F_READ)
168 return(EPERM);
169
170 /* If the name already ends in .gz or .bz2, ignore it */
171 if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
172 || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
173 return(ENOENT);
174
175 /* Construct new name */
176 zfname = malloc(strlen(fname) + 4);
177 if (zfname == NULL)
178 return(ENOMEM);
179 sprintf(zfname, "%s.gz", fname);
180
181 /* Try to open the compressed datafile */
182 rawfd = open(zfname, O_RDONLY);
183 free(zfname);
184 if (rawfd == -1)
185 return(ENOENT);
186
187 if (fstat(rawfd, &sb) < 0) {
188 printf("zf_open: stat failed\n");
189 close(rawfd);
190 return(ENOENT);
191 }
192 if (!S_ISREG(sb.st_mode)) {
193 printf("zf_open: not a file\n");
194 close(rawfd);
195 return(EISDIR); /* best guess */
196 }
197
198 /* Allocate a z_file structure, populate it */
199 zf = malloc(sizeof(struct z_file));
200 if (zf == NULL)
201 return(ENOMEM);
202 bzero(zf, sizeof(struct z_file));
203 zf->zf_rawfd = rawfd;
204
205 /* Verify that the file is gzipped */
206 if (check_header(zf)) {
207 close(zf->zf_rawfd);
208 free(zf);
209 return(EFTYPE);
210 }
211
212 /* Initialise the inflation engine */
213 if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
214 printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
215 close(zf->zf_rawfd);
216 free(zf);
217 return(EIO);
218 }
219
220 /* Looks OK, we'll take it */
221 f->f_fsdata = zf;
222 return(0);
223 }
224
225 static int
zf_close(struct open_file * f)226 zf_close(struct open_file *f)
227 {
228 struct z_file *zf = (struct z_file *)f->f_fsdata;
229
230 inflateEnd(&(zf->zf_zstream));
231 close(zf->zf_rawfd);
232 free(zf);
233 return(0);
234 }
235
236 static int
zf_read(struct open_file * f,void * buf,size_t size,size_t * resid)237 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
238 {
239 struct z_file *zf = (struct z_file *)f->f_fsdata;
240 int error;
241
242 zf->zf_zstream.next_out = buf; /* where and how much */
243 zf->zf_zstream.avail_out = size;
244
245 while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
246 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
247 printf("zf_read: fill error\n");
248 return(EIO);
249 }
250 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
251 printf("zf_read: unexpected EOF\n");
252 if (zf->zf_zstream.avail_out == size)
253 return(EIO);
254 break;
255 }
256
257 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
258 if (error == Z_STREAM_END) { /* EOF, all done */
259 zf->zf_endseen = 1;
260 break;
261 }
262 if (error != Z_OK) { /* argh, decompression error */
263 printf("inflate: %s\n", zf->zf_zstream.msg);
264 return(EIO);
265 }
266 }
267 if (resid != NULL)
268 *resid = zf->zf_zstream.avail_out;
269 return(0);
270 }
271
272 static int
zf_rewind(struct open_file * f)273 zf_rewind(struct open_file *f)
274 {
275 struct z_file *zf = (struct z_file *)f->f_fsdata;
276
277 if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
278 return(-1);
279 zf->zf_zstream.avail_in = 0;
280 zf->zf_zstream.next_in = NULL;
281 zf->zf_endseen = 0;
282 (void)inflateReset(&zf->zf_zstream);
283
284 return(0);
285 }
286
287 static off_t
zf_seek(struct open_file * f,off_t offset,int where)288 zf_seek(struct open_file *f, off_t offset, int where)
289 {
290 struct z_file *zf = (struct z_file *)f->f_fsdata;
291 off_t target;
292 char discard[16];
293
294 switch (where) {
295 case SEEK_SET:
296 target = offset;
297 break;
298 case SEEK_CUR:
299 target = offset + zf->zf_zstream.total_out;
300 break;
301 default:
302 errno = EINVAL;
303 return(-1);
304 }
305
306 /* rewind if required */
307 if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
308 return(-1);
309
310 /* skip forwards if required */
311 while (target > zf->zf_zstream.total_out) {
312 errno = zf_read(f, discard, min(sizeof(discard),
313 target - zf->zf_zstream.total_out), NULL);
314 if (errno)
315 return(-1);
316 /* Break out of loop if end of file has been reached. */
317 if (zf->zf_endseen)
318 break;
319 }
320 /* This is where we are (be honest if we overshot) */
321 return(zf->zf_zstream.total_out);
322 }
323
324
325 static int
zf_stat(struct open_file * f,struct stat * sb)326 zf_stat(struct open_file *f, struct stat *sb)
327 {
328 struct z_file *zf = (struct z_file *)f->f_fsdata;
329 int result;
330
331 /* stat as normal, but indicate that size is unknown */
332 if ((result = fstat(zf->zf_rawfd, sb)) == 0)
333 sb->st_size = -1;
334 return(result);
335 }
336
337
338
339