1 /*
2 * Copyright (c) 1998 Michael Smith.
3 * Copyright (c) 2000 Maxim Sobolev
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #ifndef REGRESSION
29 #include "stand.h"
30 #else
31 #include <stdlib.h>
32 #include <sys/errno.h>
33 #include <sys/fcntl.h>
34 #include <sys/types.h>
35 #include <sys/unistd.h>
36
37 struct open_file {
38 int f_flags; /* see F_* below */
39 void *f_fsdata; /* file system specific data */
40 };
41 #define F_READ 0x0001 /* file opened for reading */
42 #define EOFFSET (ELAST+8) /* relative seek not supported */
min(u_int a,u_int b)43 static inline u_int min(u_int a, u_int b) { return(a < b ? a : b); }
44 #define panic(x, y) abort()
45 #endif
46
47 #include <sys/stat.h>
48 #include <string.h>
49 #include <bzlib.h>
50
51 #define BZ_BUFSIZE 2048 /* XXX larger? */
52
53 struct bz_file
54 {
55 int bzf_rawfd;
56 bz_stream bzf_bzstream;
57 char bzf_buf[BZ_BUFSIZE];
58 int bzf_endseen;
59 };
60
61 static int bzf_fill(struct bz_file *z);
62 static int bzf_open(const char *path, struct open_file *f);
63 static int bzf_close(struct open_file *f);
64 static int bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
65 static off_t bzf_seek(struct open_file *f, off_t offset, int where);
66 static int bzf_stat(struct open_file *f, struct stat *sb);
67
68 #ifndef REGRESSION
69 struct fs_ops bzipfs_fsops = {
70 .fs_name = "bzip",
71 .fo_open = bzf_open,
72 .fo_close = bzf_close,
73 .fo_read = bzf_read,
74 .fo_write = null_write,
75 .fo_seek = bzf_seek,
76 .fo_stat = bzf_stat,
77 .fo_readdir = null_readdir,
78 };
79 #endif
80
81 static int
bzf_fill(struct bz_file * bzf)82 bzf_fill(struct bz_file *bzf)
83 {
84 int result;
85 int req;
86
87 req = BZ_BUFSIZE - bzf->bzf_bzstream.avail_in;
88 result = 0;
89
90 /* If we need more */
91 if (req > 0) {
92 /* move old data to bottom of buffer */
93 if (req < BZ_BUFSIZE)
94 bcopy(bzf->bzf_buf + req, bzf->bzf_buf, BZ_BUFSIZE - req);
95
96 /* read to fill buffer and update availibility data */
97 result = read(bzf->bzf_rawfd, bzf->bzf_buf + bzf->bzf_bzstream.avail_in, req);
98 bzf->bzf_bzstream.next_in = bzf->bzf_buf;
99 if (result >= 0)
100 bzf->bzf_bzstream.avail_in += result;
101 }
102 return(result);
103 }
104
105 /*
106 * Adapted from get_byte/check_header in libz
107 *
108 * Returns 0 if the header is OK, nonzero if not.
109 */
110 static int
get_byte(struct bz_file * bzf)111 get_byte(struct bz_file *bzf)
112 {
113 if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1))
114 return(-1);
115 bzf->bzf_bzstream.avail_in--;
116 return(*(bzf->bzf_bzstream.next_in)++);
117 }
118
119 static int bz_magic[3] = {'B', 'Z', 'h'}; /* bzip2 magic header */
120
121 static int
check_header(struct bz_file * bzf)122 check_header(struct bz_file *bzf)
123 {
124 unsigned int len;
125 int c;
126
127 /* Check the bzip2 magic header */
128 for (len = 0; len < 3; len++) {
129 c = get_byte(bzf);
130 if (c != bz_magic[len]) {
131 return(1);
132 }
133 }
134 /* Check that the block size is valid */
135 c = get_byte(bzf);
136 if (c < '1' || c > '9')
137 return(1);
138
139 /* Put back bytes that we've took from the input stream */
140 bzf->bzf_bzstream.next_in -= 4;
141 bzf->bzf_bzstream.avail_in += 4;
142
143 return(0);
144 }
145
146 static int
bzf_open(const char * fname,struct open_file * f)147 bzf_open(const char *fname, struct open_file *f)
148 {
149 static char *bzfname;
150 int rawfd;
151 struct bz_file *bzf;
152 char *cp;
153 int error;
154 struct stat sb;
155
156 /* Have to be in "just read it" mode */
157 if (f->f_flags != F_READ)
158 return(EPERM);
159
160 /* If the name already ends in .gz or .bz2, ignore it */
161 if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
162 || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
163 return(ENOENT);
164
165 /* Construct new name */
166 bzfname = malloc(strlen(fname) + 5);
167 if (bzfname == NULL)
168 return(ENOMEM);
169 sprintf(bzfname, "%s.bz2", fname);
170
171 /* Try to open the compressed datafile */
172 rawfd = open(bzfname, O_RDONLY);
173 free(bzfname);
174 if (rawfd == -1)
175 return(ENOENT);
176
177 if (fstat(rawfd, &sb) < 0) {
178 printf("bzf_open: stat failed\n");
179 close(rawfd);
180 return(ENOENT);
181 }
182 if (!S_ISREG(sb.st_mode)) {
183 printf("bzf_open: not a file\n");
184 close(rawfd);
185 return(EISDIR); /* best guess */
186 }
187
188 /* Allocate a bz_file structure, populate it */
189 bzf = malloc(sizeof(struct bz_file));
190 if (bzf == NULL)
191 return(ENOMEM);
192 bzero(bzf, sizeof(struct bz_file));
193 bzf->bzf_rawfd = rawfd;
194
195 /* Verify that the file is bzipped */
196 if (check_header(bzf)) {
197 close(bzf->bzf_rawfd);
198 free(bzf);
199 return(EFTYPE);
200 }
201
202 /* Initialise the inflation engine */
203 if ((error = BZ2_bzDecompressInit(&(bzf->bzf_bzstream), 0, 1)) != BZ_OK) {
204 printf("bzf_open: BZ2_bzDecompressInit returned %d\n", error);
205 close(bzf->bzf_rawfd);
206 free(bzf);
207 return(EIO);
208 }
209
210 /* Looks OK, we'll take it */
211 f->f_fsdata = bzf;
212 return(0);
213 }
214
215 static int
bzf_close(struct open_file * f)216 bzf_close(struct open_file *f)
217 {
218 struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
219
220 BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
221 close(bzf->bzf_rawfd);
222 free(bzf);
223 return(0);
224 }
225
226 static int
bzf_read(struct open_file * f,void * buf,size_t size,size_t * resid)227 bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
228 {
229 struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
230 int error;
231
232 bzf->bzf_bzstream.next_out = buf; /* where and how much */
233 bzf->bzf_bzstream.avail_out = size;
234
235 while (bzf->bzf_bzstream.avail_out && bzf->bzf_endseen == 0) {
236 if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1)) {
237 printf("bzf_read: fill error\n");
238 return(EIO);
239 }
240 if (bzf->bzf_bzstream.avail_in == 0) { /* oops, unexpected EOF */
241 printf("bzf_read: unexpected EOF\n");
242 if (bzf->bzf_bzstream.avail_out == size)
243 return(EIO);
244 break;
245 }
246
247 error = BZ2_bzDecompress(&bzf->bzf_bzstream); /* decompression pass */
248 if (error == BZ_STREAM_END) { /* EOF, all done */
249 bzf->bzf_endseen = 1;
250 break;
251 }
252 if (error != BZ_OK) { /* argh, decompression error */
253 printf("bzf_read: BZ2_bzDecompress returned %d\n", error);
254 return(EIO);
255 }
256 }
257 if (resid != NULL)
258 *resid = bzf->bzf_bzstream.avail_out;
259 return(0);
260 }
261
262 static int
bzf_rewind(struct open_file * f)263 bzf_rewind(struct open_file *f)
264 {
265 struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
266 struct bz_file *bzf_tmp;
267
268 /*
269 * Since bzip2 does not have an equivalent inflateReset function a crude
270 * one needs to be provided. The functions all called in such a way that
271 * at any time an error occurs a roll back can be done (effectively making
272 * this rewind 'atomic', either the reset occurs successfully or not at all,
273 * with no 'undefined' state happening).
274 */
275
276 /* Allocate a bz_file structure, populate it */
277 bzf_tmp = malloc(sizeof(struct bz_file));
278 if (bzf_tmp == NULL)
279 return(-1);
280 bzero(bzf_tmp, sizeof(struct bz_file));
281 bzf_tmp->bzf_rawfd = bzf->bzf_rawfd;
282
283 /* Initialise the inflation engine */
284 if (BZ2_bzDecompressInit(&(bzf_tmp->bzf_bzstream), 0, 1) != BZ_OK) {
285 free(bzf_tmp);
286 return(-1);
287 }
288
289 /* Seek back to the beginning of the file */
290 if (lseek(bzf->bzf_rawfd, 0, SEEK_SET) == -1) {
291 BZ2_bzDecompressEnd(&(bzf_tmp->bzf_bzstream));
292 free(bzf_tmp);
293 return(-1);
294 }
295
296 /* Free old bz_file data */
297 BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
298 free(bzf);
299
300 /* Use the new bz_file data */
301 f->f_fsdata = bzf_tmp;
302
303 return(0);
304 }
305
306 static off_t
bzf_seek(struct open_file * f,off_t offset,int where)307 bzf_seek(struct open_file *f, off_t offset, int where)
308 {
309 struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
310 off_t target;
311 char discard[16];
312
313 switch (where) {
314 case SEEK_SET:
315 target = offset;
316 break;
317 case SEEK_CUR:
318 target = offset + bzf->bzf_bzstream.total_out_lo32;
319 break;
320 default:
321 errno = EINVAL;
322 return(-1);
323 }
324
325 /* Can we get there from here? */
326 if (target < bzf->bzf_bzstream.total_out_lo32 && bzf_rewind(f) != 0) {
327 errno = EOFFSET;
328 return -1;
329 }
330
331 /* if bzf_rewind was called then bzf has changed */
332 bzf = (struct bz_file *)f->f_fsdata;
333
334 /* skip forwards if required */
335 while (target > bzf->bzf_bzstream.total_out_lo32) {
336 errno = bzf_read(f, discard, min(sizeof(discard),
337 target - bzf->bzf_bzstream.total_out_lo32), NULL);
338 if (errno)
339 return(-1);
340 /* Break out of loop if end of file has been reached. */
341 if (bzf->bzf_endseen)
342 break;
343 }
344 /* This is where we are (be honest if we overshot) */
345 return(bzf->bzf_bzstream.total_out_lo32);
346 }
347
348 static int
bzf_stat(struct open_file * f,struct stat * sb)349 bzf_stat(struct open_file *f, struct stat *sb)
350 {
351 struct bz_file *bzf = (struct bz_file *)f->f_fsdata;
352 int result;
353
354 /* stat as normal, but indicate that size is unknown */
355 if ((result = fstat(bzf->bzf_rawfd, sb)) == 0)
356 sb->st_size = -1;
357 return(result);
358 }
359
360 void
bz_internal_error(int errorcode)361 bz_internal_error(int errorcode)
362 {
363 panic("bzipfs: critical error %d in bzip2 library occurred", errorcode);
364 }
365
366 #ifdef REGRESSION
367 /* Small test case, open and decompress test.bz2 */
main(void)368 int main(void)
369 {
370 struct open_file f;
371 char buf[1024];
372 size_t resid;
373 int err;
374
375 memset(&f, '\0', sizeof(f));
376 f.f_flags = F_READ;
377 err = bzf_open("test", &f);
378 if (err != 0)
379 exit(1);
380 do {
381 err = bzf_read(&f, buf, sizeof(buf), &resid);
382 } while (err == 0 && resid != sizeof(buf));
383
384 if (err != 0)
385 exit(2);
386 exit(0);
387 }
388 #endif
389