| 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 | * $FreeBSD: src/lib/libstand/gzipfs.c,v 1.11 2002/12/19 19:34:58 jake Exp $ |
| 27 | * $DragonFly: src/lib/libstand/gzipfs.c,v 1.1 2003/11/10 06:14:44 dillon Exp $ |
| 28 | */ |
| 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 | z_stream zf_zstream; |
| 42 | char zf_buf[Z_BUFSIZE]; |
| 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 | "zip", |
| 54 | zf_open, |
| 55 | zf_close, |
| 56 | zf_read, |
| 57 | null_write, |
| 58 | zf_seek, |
| 59 | zf_stat, |
| 60 | null_readdir |
| 61 | }; |
| 62 | |
| 63 | #if 0 |
| 64 | void * |
| 65 | calloc(int items, size_t size) |
| 66 | { |
| 67 | return(malloc(items * size)); |
| 68 | } |
| 69 | #endif |
| 70 | |
| 71 | static int |
| 72 | zf_fill(struct z_file *zf) |
| 73 | { |
| 74 | int result; |
| 75 | int req; |
| 76 | |
| 77 | req = Z_BUFSIZE - zf->zf_zstream.avail_in; |
| 78 | result = 0; |
| 79 | |
| 80 | /* If we need more */ |
| 81 | if (req > 0) { |
| 82 | /* move old data to bottom of buffer */ |
| 83 | if (req < Z_BUFSIZE) |
| 84 | bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req); |
| 85 | |
| 86 | /* read to fill buffer and update availibility data */ |
| 87 | result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req); |
| 88 | zf->zf_zstream.next_in = zf->zf_buf; |
| 89 | if (result >= 0) |
| 90 | zf->zf_zstream.avail_in += result; |
| 91 | } |
| 92 | return(result); |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Adapted from get_byte/check_header in libz |
| 97 | * |
| 98 | * Returns 0 if the header is OK, nonzero if not. |
| 99 | */ |
| 100 | static int |
| 101 | get_byte(struct z_file *zf) |
| 102 | { |
| 103 | if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) |
| 104 | return(-1); |
| 105 | zf->zf_zstream.avail_in--; |
| 106 | return(*(zf->zf_zstream.next_in)++); |
| 107 | } |
| 108 | |
| 109 | static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ |
| 110 | |
| 111 | /* gzip flag byte */ |
| 112 | #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ |
| 113 | #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ |
| 114 | #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ |
| 115 | #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ |
| 116 | #define COMMENT 0x10 /* bit 4 set: file comment present */ |
| 117 | #define RESERVED 0xE0 /* bits 5..7: reserved */ |
| 118 | |
| 119 | static int |
| 120 | check_header(struct z_file *zf) |
| 121 | { |
| 122 | int method; /* method byte */ |
| 123 | int flags; /* flags byte */ |
| 124 | uInt len; |
| 125 | int c; |
| 126 | |
| 127 | /* Check the gzip magic header */ |
| 128 | for (len = 0; len < 2; len++) { |
| 129 | c = get_byte(zf); |
| 130 | if (c != gz_magic[len]) { |
| 131 | return(1); |
| 132 | } |
| 133 | } |
| 134 | method = get_byte(zf); |
| 135 | flags = get_byte(zf); |
| 136 | if (method != Z_DEFLATED || (flags & RESERVED) != 0) { |
| 137 | return(1); |
| 138 | } |
| 139 | |
| 140 | /* Discard time, xflags and OS code: */ |
| 141 | for (len = 0; len < 6; len++) (void)get_byte(zf); |
| 142 | |
| 143 | if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ |
| 144 | len = (uInt)get_byte(zf); |
| 145 | len += ((uInt)get_byte(zf))<<8; |
| 146 | /* len is garbage if EOF but the loop below will quit anyway */ |
| 147 | while (len-- != 0 && get_byte(zf) != -1) ; |
| 148 | } |
| 149 | if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ |
| 150 | while ((c = get_byte(zf)) != 0 && c != -1) ; |
| 151 | } |
| 152 | if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ |
| 153 | while ((c = get_byte(zf)) != 0 && c != -1) ; |
| 154 | } |
| 155 | if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ |
| 156 | for (len = 0; len < 2; len++) c = get_byte(zf); |
| 157 | } |
| 158 | /* if there's data left, we're in business */ |
| 159 | return((c == -1) ? 1 : 0); |
| 160 | } |
| 161 | |
| 162 | static int |
| 163 | zf_open(const char *fname, struct open_file *f) |
| 164 | { |
| 165 | char *zfname; |
| 166 | int rawfd; |
| 167 | struct z_file *zf; |
| 168 | char *cp; |
| 169 | int error; |
| 170 | struct stat sb; |
| 171 | |
| 172 | /* Have to be in "just read it" mode */ |
| 173 | if (f->f_flags != F_READ) |
| 174 | return(EPERM); |
| 175 | |
| 176 | /* If the name already ends in .gz or .bz2, ignore it */ |
| 177 | if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz") |
| 178 | || !strcmp(cp, ".bz2") || !strcmp(cp, ".split"))) |
| 179 | return(ENOENT); |
| 180 | |
| 181 | /* Construct new name */ |
| 182 | zfname = malloc(strlen(fname) + 4); |
| 183 | if (zfname == NULL) |
| 184 | return(ENOMEM); |
| 185 | sprintf(zfname, "%s.gz", fname); |
| 186 | /* Try to open the compressed datafile */ |
| 187 | rawfd = open(zfname, O_RDONLY); |
| 188 | free(zfname); |
| 189 | if (rawfd == -1) |
| 190 | return(ENOENT); |
| 191 | |
| 192 | if (fstat(rawfd, &sb) < 0) { |
| 193 | printf("zf_open: stat failed\n"); |
| 194 | close(rawfd); |
| 195 | return(ENOENT); |
| 196 | } |
| 197 | if (!S_ISREG(sb.st_mode)) { |
| 198 | printf("zf_open: not a file\n"); |
| 199 | close(rawfd); |
| 200 | return(EISDIR); /* best guess */ |
| 201 | } |
| 202 | |
| 203 | /* Allocate a z_file structure, populate it */ |
| 204 | zf = malloc(sizeof(struct z_file)); |
| 205 | if (zf == NULL) |
| 206 | return(ENOMEM); |
| 207 | bzero(zf, sizeof(struct z_file)); |
| 208 | zf->zf_rawfd = rawfd; |
| 209 | |
| 210 | /* Verify that the file is gzipped (XXX why do this afterwards?) */ |
| 211 | if (check_header(zf)) { |
| 212 | close(zf->zf_rawfd); |
| 213 | inflateEnd(&(zf->zf_zstream)); |
| 214 | free(zf); |
| 215 | return(EFTYPE); |
| 216 | } |
| 217 | |
| 218 | /* Initialise the inflation engine */ |
| 219 | if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) { |
| 220 | printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg); |
| 221 | close(zf->zf_rawfd); |
| 222 | free(zf); |
| 223 | return(EIO); |
| 224 | } |
| 225 | |
| 226 | /* Looks OK, we'll take it */ |
| 227 | f->f_fsdata = zf; |
| 228 | return(0); |
| 229 | } |
| 230 | |
| 231 | static int |
| 232 | zf_close(struct open_file *f) |
| 233 | { |
| 234 | struct z_file *zf = (struct z_file *)f->f_fsdata; |
| 235 | |
| 236 | f->f_fsdata = NULL; |
| 237 | if (zf) { |
| 238 | inflateEnd(&(zf->zf_zstream)); |
| 239 | close(zf->zf_rawfd); |
| 240 | free(zf); |
| 241 | } |
| 242 | return(0); |
| 243 | } |
| 244 | |
| 245 | static int |
| 246 | zf_read(struct open_file *f, void *buf, size_t size, size_t *resid) |
| 247 | { |
| 248 | struct z_file *zf = (struct z_file *)f->f_fsdata; |
| 249 | int error; |
| 250 | |
| 251 | zf->zf_zstream.next_out = buf; /* where and how much */ |
| 252 | zf->zf_zstream.avail_out = size; |
| 253 | |
| 254 | while (zf->zf_zstream.avail_out) { |
| 255 | if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) { |
| 256 | printf("zf_read: fill error\n"); |
| 257 | return(-1); |
| 258 | } |
| 259 | if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */ |
| 260 | printf("zf_read: unexpected EOF\n"); |
| 261 | break; |
| 262 | } |
| 263 | |
| 264 | error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */ |
| 265 | if (error == Z_STREAM_END) { /* EOF, all done */ |
| 266 | break; |
| 267 | } |
| 268 | if (error != Z_OK) { /* argh, decompression error */ |
| 269 | printf("inflate: %s\n", zf->zf_zstream.msg); |
| 270 | errno = EIO; |
| 271 | return(-1); |
| 272 | } |
| 273 | } |
| 274 | if (resid != NULL) |
| 275 | *resid = zf->zf_zstream.avail_out; |
| 276 | return(0); |
| 277 | } |
| 278 | |
| 279 | static off_t |
| 280 | zf_seek(struct open_file *f, off_t offset, int where) |
| 281 | { |
| 282 | struct z_file *zf = (struct z_file *)f->f_fsdata; |
| 283 | off_t target; |
| 284 | char discard[16]; |
| 285 | |
| 286 | switch (where) { |
| 287 | case SEEK_SET: |
| 288 | target = offset; |
| 289 | break; |
| 290 | case SEEK_CUR: |
| 291 | target = offset + zf->zf_zstream.total_out; |
| 292 | break; |
| 293 | default: |
| 294 | target = -1; |
| 295 | } |
| 296 | |
| 297 | /* Can we get there from here? */ |
| 298 | if (target < zf->zf_zstream.total_out) { |
| 299 | errno = EOFFSET; |
| 300 | return -1; |
| 301 | } |
| 302 | |
| 303 | /* skip forwards if required */ |
| 304 | while (target > zf->zf_zstream.total_out) { |
| 305 | if (zf_read(f, discard, min(sizeof(discard), target - zf->zf_zstream.total_out), NULL) == -1) |
| 306 | return(-1); |
| 307 | } |
| 308 | /* This is where we are (be honest if we overshot) */ |
| 309 | return (zf->zf_zstream.total_out); |
| 310 | } |
| 311 | |
| 312 | |
| 313 | static int |
| 314 | zf_stat(struct open_file *f, struct stat *sb) |
| 315 | { |
| 316 | struct z_file *zf = (struct z_file *)f->f_fsdata; |
| 317 | int result; |
| 318 | |
| 319 | /* stat as normal, but indicate that size is unknown */ |
| 320 | if ((result = fstat(zf->zf_rawfd, sb)) == 0) |
| 321 | sb->st_size = -1; |
| 322 | return(result); |
| 323 | } |
| 324 | |
| 325 | |
| 326 | |