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