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 <sys/cdefs.h>
28
29 #include "stand.h"
30
31 #include <sys/stat.h>
32 #include <string.h>
33 #include <zlib.h>
34
35 #define Z_BUFSIZE 16384 /* match NFSREAD_MAX_SIZE */
36
37 struct z_file
38 {
39 int zf_rawfd;
40 off_t zf_dataoffset;
41 z_stream zf_zstream;
42 int zf_endseen;
43 unsigned char zf_buf[Z_BUFSIZE];
44 };
45
46 static int zf_fill(struct z_file *z);
47 static int zf_open(const char *path, struct open_file *f);
48 static int zf_close(struct open_file *f);
49 static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
50 static off_t zf_seek(struct open_file *f, off_t offset, int where);
51 static int zf_stat(struct open_file *f, struct stat *sb);
52
53 struct fs_ops gzipfs_fsops = {
54 .fs_name = "zip",
55 .fo_open = zf_open,
56 .fo_close = zf_close,
57 .fo_read = zf_read,
58 .fo_write = null_write,
59 .fo_seek = zf_seek,
60 .fo_stat = zf_stat,
61 .fo_readdir = null_readdir
62 };
63
64 static int
zf_fill(struct z_file * zf)65 zf_fill(struct z_file *zf)
66 {
67 int result;
68 int req;
69
70 req = Z_BUFSIZE - zf->zf_zstream.avail_in;
71 result = 0;
72
73 /* If we need more */
74 if (req > 0) {
75 /* move old data to bottom of buffer */
76 if (req < Z_BUFSIZE)
77 bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
78
79 /* read to fill buffer and update availibility data */
80 result = read(zf->zf_rawfd,
81 zf->zf_buf + zf->zf_zstream.avail_in, req);
82 zf->zf_zstream.next_in = zf->zf_buf;
83 if (result >= 0)
84 zf->zf_zstream.avail_in += result;
85 }
86 return (result);
87 }
88
89 /*
90 * Adapted from get_byte/check_header in libz
91 *
92 * Returns 0 if the header is OK, nonzero if not.
93 */
94 static int
get_byte(struct z_file * zf,off_t * curoffp)95 get_byte(struct z_file *zf, off_t *curoffp)
96 {
97 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
98 return (-1);
99 zf->zf_zstream.avail_in--;
100 ++*curoffp;
101 return (*(zf->zf_zstream.next_in)++);
102 }
103
104 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
105
106 /* gzip flag byte */
107 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
108 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
109 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
110 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
111 #define COMMENT 0x10 /* bit 4 set: file comment present */
112 #define RESERVED 0xE0 /* bits 5..7: reserved */
113
114 static int
check_header(struct z_file * zf)115 check_header(struct z_file *zf)
116 {
117 int method; /* method byte */
118 int flags; /* flags byte */
119 uInt len;
120 int c;
121
122 zf->zf_dataoffset = 0;
123 /* Check the gzip magic header */
124 for (len = 0; len < 2; len++) {
125 c = get_byte(zf, &zf->zf_dataoffset);
126 if (c != gz_magic[len]) {
127 return (1);
128 }
129 }
130 method = get_byte(zf, &zf->zf_dataoffset);
131 flags = get_byte(zf, &zf->zf_dataoffset);
132 if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
133 return (1);
134 }
135
136 /* Discard time, xflags and OS code: */
137 for (len = 0; len < 6; len++)
138 (void) get_byte(zf, &zf->zf_dataoffset);
139
140 if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
141 len = (uInt)get_byte(zf, &zf->zf_dataoffset);
142 len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
143 /* len is garbage if EOF but the loop below will quit anyway */
144 while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1)
145 ;
146 }
147 if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
148 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1)
149 ;
150 }
151 if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
152 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1)
153 ;
154 }
155 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
156 for (len = 0; len < 2; len++)
157 c = get_byte(zf, &zf->zf_dataoffset);
158 }
159 /* if there's data left, we're in business */
160 return ((c == -1) ? 1 : 0);
161 }
162
163 static int
zf_open(const char * fname,struct open_file * f)164 zf_open(const char *fname, struct open_file *f)
165 {
166 char *zfname;
167 int rawfd;
168 struct z_file *zf;
169 char *cp;
170 int error;
171 struct stat sb;
172 size_t len;
173
174 /* Have to be in "just read it" mode */
175 if (f->f_flags != F_READ)
176 return (EPERM);
177
178 /* directory names are not compressed. */
179 len = strlen(fname);
180 if (len == 0 || fname[len - 1] == '/')
181 return (ENOENT);
182
183 /* If the name already ends in .gz or .bz2, ignore it */
184 if ((cp = strrchr(fname, '.')) && (strcmp(cp, ".gz") == 0 ||
185 strcmp(cp, ".bz2") == 0 || strcmp(cp, ".split") == 0))
186 return (ENOENT);
187
188 /* Try to open the compressed datafile */
189 rawfd = open(fname, O_RDONLY | F_GZIP);
190 if (rawfd == -1) {
191 /* add .gz sufix and try again */
192 zfname = malloc(strlen(fname) + 4);
193 if (zfname == NULL)
194 return (ENOMEM);
195 sprintf(zfname, "%s.gz", fname);
196 rawfd = open(zfname, O_RDONLY);
197 free(zfname);
198 if (rawfd == -1)
199 return (ENOENT);
200 }
201
202 if (fstat(rawfd, &sb) < 0) {
203 printf("zf_open: stat failed\n");
204 close(rawfd);
205 return (ENOENT);
206 }
207 if (!S_ISREG(sb.st_mode)) {
208 close(rawfd);
209 return (EISDIR); /* best guess */
210 }
211
212 /* Allocate a z_file structure, populate it */
213 zf = malloc(sizeof (struct z_file));
214 if (zf == NULL)
215 return (ENOMEM);
216 bzero(zf, sizeof (struct z_file));
217 zf->zf_rawfd = rawfd;
218
219 /* Verify that the file is gzipped */
220 if (check_header(zf)) {
221 close(zf->zf_rawfd);
222 free(zf);
223 return (EFTYPE);
224 }
225
226 /* Initialise the inflation engine */
227 if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
228 printf("zf_open: inflateInit returned %d : %s\n", error,
229 zf->zf_zstream.msg);
230 close(zf->zf_rawfd);
231 free(zf);
232 return (EIO);
233 }
234
235 /* Looks OK, we'll take it */
236 f->f_fsdata = zf;
237 return (0);
238 }
239
240 static int
zf_close(struct open_file * f)241 zf_close(struct open_file *f)
242 {
243 struct z_file *zf = (struct z_file *)f->f_fsdata;
244
245 inflateEnd(&(zf->zf_zstream));
246 close(zf->zf_rawfd);
247 free(zf);
248 return (0);
249 }
250
251 static int
zf_read(struct open_file * f,void * buf,size_t size,size_t * resid)252 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
253 {
254 struct z_file *zf = (struct z_file *)f->f_fsdata;
255 int error;
256
257 zf->zf_zstream.next_out = buf; /* where and how much */
258 zf->zf_zstream.avail_out = size;
259
260 while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
261 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
262 printf("zf_read: fill error\n");
263 return (EIO);
264 }
265 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
266 printf("zf_read: unexpected EOF\n");
267 if (zf->zf_zstream.avail_out == size)
268 return (EIO);
269 break;
270 }
271
272 /* decompression pass */
273 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH);
274 if (error == Z_STREAM_END) { /* EOF, all done */
275 zf->zf_endseen = 1;
276 break;
277 }
278 if (error != Z_OK) { /* argh, decompression error */
279 printf("inflate: %s\n", zf->zf_zstream.msg);
280 return (EIO);
281 }
282 }
283 if (resid != NULL)
284 *resid = zf->zf_zstream.avail_out;
285 return (0);
286 }
287
288 static int
zf_rewind(struct open_file * f)289 zf_rewind(struct open_file *f)
290 {
291 struct z_file *zf = (struct z_file *)f->f_fsdata;
292
293 if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
294 return (-1);
295 zf->zf_zstream.avail_in = 0;
296 zf->zf_zstream.next_in = NULL;
297 zf->zf_endseen = 0;
298 (void) inflateReset(&zf->zf_zstream);
299
300 return (0);
301 }
302
303 static off_t
zf_seek(struct open_file * f,off_t offset,int where)304 zf_seek(struct open_file *f, off_t offset, int where)
305 {
306 struct z_file *zf = (struct z_file *)f->f_fsdata;
307 off_t target;
308 char discard[16];
309
310 switch (where) {
311 case SEEK_SET:
312 target = offset;
313 break;
314 case SEEK_CUR:
315 target = offset + zf->zf_zstream.total_out;
316 break;
317 default:
318 errno = EINVAL;
319 return (-1);
320 }
321
322 /* rewind if required */
323 if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
324 return (-1);
325
326 /* skip forwards if required */
327 while (target > zf->zf_zstream.total_out) {
328 errno = zf_read(f, discard, min(sizeof (discard),
329 target - zf->zf_zstream.total_out), NULL);
330 if (errno != 0)
331 return (-1);
332 }
333 /* This is where we are (be honest if we overshot) */
334 return (zf->zf_zstream.total_out);
335 }
336
337
338 static int
zf_stat(struct open_file * f,struct stat * sb)339 zf_stat(struct open_file *f, struct stat *sb)
340 {
341 struct z_file *zf = (struct z_file *)f->f_fsdata;
342 int result;
343 off_t pos1, pos2;
344 uint32_t size;
345
346 /* stat as normal, but indicate that size is unknown */
347 if ((result = fstat(zf->zf_rawfd, sb)) == 0) {
348 if (sb->st_size == -1)
349 return (result);
350 pos1 = lseek(zf->zf_rawfd, 0, SEEK_CUR);
351 pos2 = lseek(zf->zf_rawfd, sb->st_size - 4, SEEK_SET);
352 if (pos2 != -1) {
353 if (read(zf->zf_rawfd, &size, 4) == 4)
354 sb->st_size = (off_t)size;
355 else
356 sb->st_size = -1;
357 } else
358 sb->st_size = -1;
359
360 pos1 = lseek(zf->zf_rawfd, pos1, SEEK_SET);
361 }
362 return (result);
363 }
364