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 35struct 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 44static int zf_fill(struct z_file *z); 45static int zf_open(const char *path, struct open_file *f); 46static int zf_close(struct open_file *f); 47static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid); 48static off_t zf_seek(struct open_file *f, off_t offset, int where); 49static int zf_stat(struct open_file *f, struct stat *sb); 50 51struct 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 62static int 63zf_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 */ 91static int 92get_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 101static 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 111static int 112check_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 155static int 156zf_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 224static int 225zf_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 235static int 236zf_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 271static int 272zf_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 286static off_t 287zf_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 324static int 325zf_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