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 #include "stand.h" 29 30 #include <sys/stat.h> 31 #include <string.h> 32 #include <zlib.h> 33 34 #define Z_BUFSIZE 2048 /* XXX larger? */ 35 36 struct z_file 37 { 38 int zf_rawfd; 39 off_t zf_dataoffset; 40 z_stream zf_zstream; 41 unsigned char zf_buf[Z_BUFSIZE]; 42 int zf_endseen; 43 }; 44 45 static int zf_fill(struct z_file *z); 46 static int zf_open(const char *path, struct open_file *f); 47 static int zf_close(struct open_file *f); 48 static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid); 49 static off_t zf_seek(struct open_file *f, off_t offset, int where); 50 static int zf_stat(struct open_file *f, struct stat *sb); 51 52 struct fs_ops gzipfs_fsops = { 53 .fs_name = "zip", 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 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 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 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 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 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 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 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 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 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