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 a known compressed suffix, ignore it */
171 if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
172 || !strcmp(cp, ".bz2") || !strcmp(cp, ".xz")
173 || !strcmp(cp, ".zst") || !strcmp(cp, ".split")))
174 return(ENOENT);
175
176 /* Construct new name */
177 zfname = malloc(strlen(fname) + 4);
178 if (zfname == NULL)
179 return(ENOMEM);
180 sprintf(zfname, "%s.gz", fname);
181
182 /* Try to open the compressed datafile */
183 rawfd = open(zfname, O_RDONLY);
184 free(zfname);
185 if (rawfd == -1)
186 return(ENOENT);
187
188 if (fstat(rawfd, &sb) < 0) {
189 printf("zf_open: stat failed\n");
190 close(rawfd);
191 return(ENOENT);
192 }
193 if (!S_ISREG(sb.st_mode)) {
194 printf("zf_open: not a file\n");
195 close(rawfd);
196 return(EISDIR); /* best guess */
197 }
198
199 /* Allocate a z_file structure, populate it */
200 zf = malloc(sizeof(struct z_file));
201 if (zf == NULL)
202 return(ENOMEM);
203 bzero(zf, sizeof(struct z_file));
204 zf->zf_rawfd = rawfd;
205
206 /* Verify that the file is gzipped */
207 if (check_header(zf)) {
208 close(zf->zf_rawfd);
209 free(zf);
210 return(EFTYPE);
211 }
212
213 /* Initialise the inflation engine */
214 if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
215 printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
216 close(zf->zf_rawfd);
217 free(zf);
218 return(EIO);
219 }
220
221 /* Looks OK, we'll take it */
222 f->f_fsdata = zf;
223 return(0);
224 }
225
226 static int
zf_close(struct open_file * f)227 zf_close(struct open_file *f)
228 {
229 struct z_file *zf = (struct z_file *)f->f_fsdata;
230
231 inflateEnd(&(zf->zf_zstream));
232 close(zf->zf_rawfd);
233 free(zf);
234 return(0);
235 }
236
237 static int
zf_read(struct open_file * f,void * buf,size_t size,size_t * resid)238 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
239 {
240 struct z_file *zf = (struct z_file *)f->f_fsdata;
241 int error;
242
243 zf->zf_zstream.next_out = buf; /* where and how much */
244 zf->zf_zstream.avail_out = size;
245
246 while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
247 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
248 printf("zf_read: fill error\n");
249 return(EIO);
250 }
251 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
252 printf("zf_read: unexpected EOF\n");
253 if (zf->zf_zstream.avail_out == size)
254 return(EIO);
255 break;
256 }
257
258 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
259 if (error == Z_STREAM_END) { /* EOF, all done */
260 zf->zf_endseen = 1;
261 break;
262 }
263 if (error != Z_OK) { /* argh, decompression error */
264 printf("inflate: %s\n", zf->zf_zstream.msg);
265 return(EIO);
266 }
267 }
268 if (resid != NULL)
269 *resid = zf->zf_zstream.avail_out;
270 return(0);
271 }
272
273 static int
zf_rewind(struct open_file * f)274 zf_rewind(struct open_file *f)
275 {
276 struct z_file *zf = (struct z_file *)f->f_fsdata;
277
278 if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
279 return(-1);
280 zf->zf_zstream.avail_in = 0;
281 zf->zf_zstream.next_in = NULL;
282 zf->zf_endseen = 0;
283 (void)inflateReset(&zf->zf_zstream);
284
285 return(0);
286 }
287
288 static off_t
zf_seek(struct open_file * f,off_t offset,int where)289 zf_seek(struct open_file *f, off_t offset, int where)
290 {
291 struct z_file *zf = (struct z_file *)f->f_fsdata;
292 off_t target;
293 char discard[16];
294
295 switch (where) {
296 case SEEK_SET:
297 target = offset;
298 break;
299 case SEEK_CUR:
300 target = offset + zf->zf_zstream.total_out;
301 break;
302 default:
303 errno = EINVAL;
304 return(-1);
305 }
306
307 /* rewind if required */
308 if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
309 return(-1);
310
311 /* skip forwards if required */
312 while (target > zf->zf_zstream.total_out) {
313 errno = zf_read(f, discard, min(sizeof(discard),
314 target - zf->zf_zstream.total_out), NULL);
315 if (errno)
316 return(-1);
317 /* Break out of loop if end of file has been reached. */
318 if (zf->zf_endseen)
319 break;
320 }
321 /* This is where we are (be honest if we overshot) */
322 return(zf->zf_zstream.total_out);
323 }
324
325
326 static int
zf_stat(struct open_file * f,struct stat * sb)327 zf_stat(struct open_file *f, struct stat *sb)
328 {
329 struct z_file *zf = (struct z_file *)f->f_fsdata;
330 int result;
331
332 /* stat as normal, but indicate that size is unknown */
333 if ((result = fstat(zf->zf_rawfd, sb)) == 0)
334 sb->st_size = -1;
335 return(result);
336 }
337
338
339
340