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 __FBSDID("$FreeBSD$"); 29 30 #include "stand.h" 31 32 #include <sys/stat.h> 33 #include <string.h> 34 #include <zlib.h> 35 36 #define Z_BUFSIZE 2048 /* XXX larger? */ 37 38 struct z_file 39 { 40 int zf_rawfd; 41 off_t zf_dataoffset; 42 z_stream zf_zstream; 43 unsigned char zf_buf[Z_BUFSIZE]; 44 int zf_endseen; 45 }; 46 47 static int zf_fill(struct z_file *z); 48 static int zf_open(const char *path, struct open_file *f); 49 static int zf_close(struct open_file *f); 50 static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid); 51 static off_t zf_seek(struct open_file *f, off_t offset, int where); 52 static int zf_stat(struct open_file *f, struct stat *sb); 53 54 struct fs_ops gzipfs_fsops = { 55 "zip", 56 zf_open, 57 zf_close, 58 zf_read, 59 null_write, 60 zf_seek, 61 zf_stat, 62 null_readdir 63 }; 64 65 static int 66 zf_fill(struct z_file *zf) 67 { 68 int result; 69 int req; 70 71 req = Z_BUFSIZE - zf->zf_zstream.avail_in; 72 result = 0; 73 74 /* If we need more */ 75 if (req > 0) { 76 /* move old data to bottom of buffer */ 77 if (req < Z_BUFSIZE) 78 bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req); 79 80 /* read to fill buffer and update availibility data */ 81 result = read(zf->zf_rawfd, 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 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 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++) (void)get_byte(zf, &zf->zf_dataoffset); 138 139 if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ 140 len = (uInt)get_byte(zf, &zf->zf_dataoffset); 141 len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8; 142 /* len is garbage if EOF but the loop below will quit anyway */ 143 while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1) ; 144 } 145 if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ 146 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ; 147 } 148 if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ 149 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ; 150 } 151 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ 152 for (len = 0; len < 2; len++) c = get_byte(zf, &zf->zf_dataoffset); 153 } 154 /* if there's data left, we're in business */ 155 return((c == -1) ? 1 : 0); 156 } 157 158 static int 159 zf_open(const char *fname, struct open_file *f) 160 { 161 static char *zfname; 162 int rawfd; 163 struct z_file *zf; 164 char *cp; 165 int error; 166 struct stat sb; 167 168 /* Have to be in "just read it" mode */ 169 if (f->f_flags != F_READ) 170 return(EPERM); 171 172 /* If the name already ends in .gz or .bz2, ignore it */ 173 if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz") 174 || !strcmp(cp, ".bz2") || !strcmp(cp, ".split"))) 175 return(ENOENT); 176 177 /* Construct new name */ 178 zfname = malloc(strlen(fname) + 4); 179 if (zfname == NULL) 180 return(ENOMEM); 181 sprintf(zfname, "%s.gz", fname); 182 183 /* Try to open the compressed datafile */ 184 rawfd = open(zfname, O_RDONLY); 185 free(zfname); 186 if (rawfd == -1) 187 return(ENOENT); 188 189 if (fstat(rawfd, &sb) < 0) { 190 printf("zf_open: stat failed\n"); 191 close(rawfd); 192 return(ENOENT); 193 } 194 if (!S_ISREG(sb.st_mode)) { 195 printf("zf_open: not a file\n"); 196 close(rawfd); 197 return(EISDIR); /* best guess */ 198 } 199 200 /* Allocate a z_file structure, populate it */ 201 zf = malloc(sizeof(struct z_file)); 202 if (zf == NULL) 203 return(ENOMEM); 204 bzero(zf, sizeof(struct z_file)); 205 zf->zf_rawfd = rawfd; 206 207 /* Verify that the file is gzipped */ 208 if (check_header(zf)) { 209 close(zf->zf_rawfd); 210 free(zf); 211 return(EFTYPE); 212 } 213 214 /* Initialise the inflation engine */ 215 if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) { 216 printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg); 217 close(zf->zf_rawfd); 218 free(zf); 219 return(EIO); 220 } 221 222 /* Looks OK, we'll take it */ 223 f->f_fsdata = zf; 224 return(0); 225 } 226 227 static int 228 zf_close(struct open_file *f) 229 { 230 struct z_file *zf = (struct z_file *)f->f_fsdata; 231 232 inflateEnd(&(zf->zf_zstream)); 233 close(zf->zf_rawfd); 234 free(zf); 235 return(0); 236 } 237 238 static int 239 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid) 240 { 241 struct z_file *zf = (struct z_file *)f->f_fsdata; 242 int error; 243 244 zf->zf_zstream.next_out = buf; /* where and how much */ 245 zf->zf_zstream.avail_out = size; 246 247 while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) { 248 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) { 249 printf("zf_read: fill error\n"); 250 return(EIO); 251 } 252 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */ 253 printf("zf_read: unexpected EOF\n"); 254 if (zf->zf_zstream.avail_out == size) 255 return(EIO); 256 break; 257 } 258 259 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */ 260 if (error == Z_STREAM_END) { /* EOF, all done */ 261 zf->zf_endseen = 1; 262 break; 263 } 264 if (error != Z_OK) { /* argh, decompression error */ 265 printf("inflate: %s\n", zf->zf_zstream.msg); 266 return(EIO); 267 } 268 } 269 if (resid != NULL) 270 *resid = zf->zf_zstream.avail_out; 271 return(0); 272 } 273 274 static int 275 zf_rewind(struct open_file *f) 276 { 277 struct z_file *zf = (struct z_file *)f->f_fsdata; 278 279 if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1) 280 return(-1); 281 zf->zf_zstream.avail_in = 0; 282 zf->zf_zstream.next_in = NULL; 283 zf->zf_endseen = 0; 284 (void)inflateReset(&zf->zf_zstream); 285 286 return(0); 287 } 288 289 static off_t 290 zf_seek(struct open_file *f, off_t offset, int where) 291 { 292 struct z_file *zf = (struct z_file *)f->f_fsdata; 293 off_t target; 294 char discard[16]; 295 296 switch (where) { 297 case SEEK_SET: 298 target = offset; 299 break; 300 case SEEK_CUR: 301 target = offset + zf->zf_zstream.total_out; 302 break; 303 default: 304 errno = EINVAL; 305 return(-1); 306 } 307 308 /* rewind if required */ 309 if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0) 310 return(-1); 311 312 /* skip forwards if required */ 313 while (target > zf->zf_zstream.total_out) { 314 errno = zf_read(f, discard, min(sizeof(discard), 315 target - zf->zf_zstream.total_out), NULL); 316 if (errno) 317 return(-1); 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 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