1 /* $NetBSD: fsmagic.c,v 1.9 2014/06/13 02:08:06 christos Exp $ */ 2 /* 3 * Copyright (c) Ian F. Darwin 1986-1995. 4 * Software written by Ian F. Darwin and others; 5 * maintained 1995-present by Christos Zoulas and others. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice immediately at the beginning of the file, without modification, 12 * this list of conditions, and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 /* 30 * fsmagic - magic based on filesystem info - directory, special files, etc. 31 */ 32 33 #include "file.h" 34 35 #ifndef lint 36 #if 0 37 FILE_RCSID("@(#)$File: fsmagic.c,v 1.73 2014/05/14 23:15:42 christos Exp $") 38 #else 39 __RCSID("$NetBSD: fsmagic.c,v 1.9 2014/06/13 02:08:06 christos Exp $"); 40 #endif 41 #endif /* lint */ 42 43 #include "magic.h" 44 #include <string.h> 45 #ifdef HAVE_UNISTD_H 46 #include <unistd.h> 47 #endif 48 #include <stdlib.h> 49 /* Since major is a function on SVR4, we cannot use `ifndef major'. */ 50 #ifdef MAJOR_IN_MKDEV 51 # include <sys/mkdev.h> 52 # define HAVE_MAJOR 53 #endif 54 #ifdef MAJOR_IN_SYSMACROS 55 # include <sys/sysmacros.h> 56 # define HAVE_MAJOR 57 #endif 58 #ifdef major /* Might be defined in sys/types.h. */ 59 # define HAVE_MAJOR 60 #endif 61 #ifdef WIN32 62 # define WIN32_LEAN_AND_MEAN 63 # include <windows.h> 64 #endif 65 66 #ifndef HAVE_MAJOR 67 # define major(dev) (((dev) >> 8) & 0xff) 68 # define minor(dev) ((dev) & 0xff) 69 #endif 70 #undef HAVE_MAJOR 71 #ifdef S_IFLNK 72 private int 73 bad_link(struct magic_set *ms, int err, char *buf) 74 { 75 int mime = ms->flags & MAGIC_MIME; 76 if ((mime & MAGIC_MIME_TYPE) && 77 file_printf(ms, "inode/symlink") 78 == -1) 79 return -1; 80 else if (!mime) { 81 if (ms->flags & MAGIC_ERROR) { 82 file_error(ms, err, 83 "broken symbolic link to `%s'", buf); 84 return -1; 85 } 86 if (file_printf(ms, "broken symbolic link to `%s'", buf) == -1) 87 return -1; 88 } 89 return 1; 90 } 91 #endif 92 private int 93 handle_mime(struct magic_set *ms, int mime, const char *str) 94 { 95 if ((mime & MAGIC_MIME_TYPE)) { 96 if (file_printf(ms, "inode/%s", str) == -1) 97 return -1; 98 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 99 "; charset=") == -1) 100 return -1; 101 } 102 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 103 return -1; 104 return 0; 105 } 106 107 protected int 108 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 109 { 110 int ret, did = 0; 111 int mime = ms->flags & MAGIC_MIME; 112 #ifdef S_IFLNK 113 char buf[BUFSIZ+4]; 114 ssize_t nch; 115 struct stat tstatbuf; 116 #endif 117 118 if (ms->flags & MAGIC_APPLE) 119 return 0; 120 if (fn == NULL) 121 return 0; 122 123 #define COMMA (did++ ? ", " : "") 124 /* 125 * Fstat is cheaper but fails for files you don't have read perms on. 126 * On 4.2BSD and similar systems, use lstat() to identify symlinks. 127 */ 128 #ifdef S_IFLNK 129 if ((ms->flags & MAGIC_SYMLINK) == 0) 130 ret = lstat(fn, sb); 131 else 132 #endif 133 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 134 135 #ifdef WIN32 136 { 137 HANDLE hFile = CreateFile(fn, 0, FILE_SHARE_DELETE | 138 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, 139 NULL); 140 if (hFile != INVALID_HANDLE_VALUE) { 141 /* 142 * Stat failed, but we can still open it - assume it's 143 * a block device, if nothing else. 144 */ 145 if (ret) { 146 sb->st_mode = S_IFBLK; 147 ret = 0; 148 } 149 switch (GetFileType(hFile)) { 150 case FILE_TYPE_CHAR: 151 sb->st_mode |= S_IFCHR; 152 sb->st_mode &= ~S_IFREG; 153 break; 154 case FILE_TYPE_PIPE: 155 sb->st_mode |= S_IFIFO; 156 sb->st_mode &= ~S_IFREG; 157 break; 158 } 159 CloseHandle(hFile); 160 } 161 } 162 #endif 163 164 if (ret) { 165 if (ms->flags & MAGIC_ERROR) { 166 file_error(ms, errno, "cannot stat `%s'", fn); 167 return -1; 168 } 169 if (file_printf(ms, "cannot open `%s' (%s)", 170 fn, strerror(errno)) == -1) 171 return -1; 172 return 0; 173 } 174 175 ret = 1; 176 if (!mime) { 177 #ifdef S_ISUID 178 if (sb->st_mode & S_ISUID) 179 if (file_printf(ms, "%ssetuid", COMMA) == -1) 180 return -1; 181 #endif 182 #ifdef S_ISGID 183 if (sb->st_mode & S_ISGID) 184 if (file_printf(ms, "%ssetgid", COMMA) == -1) 185 return -1; 186 #endif 187 #ifdef S_ISVTX 188 if (sb->st_mode & S_ISVTX) 189 if (file_printf(ms, "%ssticky", COMMA) == -1) 190 return -1; 191 #endif 192 } 193 194 switch (sb->st_mode & S_IFMT) { 195 case S_IFDIR: 196 if (mime) { 197 if (handle_mime(ms, mime, "directory") == -1) 198 return -1; 199 } else if (file_printf(ms, "%sdirectory", COMMA) == -1) 200 return -1; 201 break; 202 #ifdef S_IFCHR 203 case S_IFCHR: 204 /* 205 * If -s has been specified, treat character special files 206 * like ordinary files. Otherwise, just report that they 207 * are block special files and go on to the next file. 208 */ 209 if ((ms->flags & MAGIC_DEVICES) != 0) { 210 ret = 0; 211 break; 212 } 213 if (mime) { 214 if (handle_mime(ms, mime, "chardevice") == -1) 215 return -1; 216 } else { 217 #ifdef HAVE_STRUCT_STAT_ST_RDEV 218 # ifdef dv_unit 219 if (file_printf(ms, "%scharacter special (%d/%d/%d)", 220 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 221 dv_subunit(sb->st_rdev)) == -1) 222 return -1; 223 # else 224 if (file_printf(ms, "%scharacter special (%ld/%ld)", 225 COMMA, (long)major(sb->st_rdev), 226 (long)minor(sb->st_rdev)) == -1) 227 return -1; 228 # endif 229 #else 230 if (file_printf(ms, "%scharacter special", COMMA) == -1) 231 return -1; 232 #endif 233 } 234 break; 235 #endif 236 #ifdef S_IFBLK 237 case S_IFBLK: 238 /* 239 * If -s has been specified, treat block special files 240 * like ordinary files. Otherwise, just report that they 241 * are block special files and go on to the next file. 242 */ 243 if ((ms->flags & MAGIC_DEVICES) != 0) { 244 ret = 0; 245 break; 246 } 247 if (mime) { 248 if (handle_mime(ms, mime, "blockdevice") == -1) 249 return -1; 250 } else { 251 #ifdef HAVE_STRUCT_STAT_ST_RDEV 252 # ifdef dv_unit 253 if (file_printf(ms, "%sblock special (%d/%d/%d)", 254 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 255 dv_subunit(sb->st_rdev)) == -1) 256 return -1; 257 # else 258 if (file_printf(ms, "%sblock special (%ld/%ld)", 259 COMMA, (long)major(sb->st_rdev), 260 (long)minor(sb->st_rdev)) == -1) 261 return -1; 262 # endif 263 #else 264 if (file_printf(ms, "%sblock special", COMMA) == -1) 265 return -1; 266 #endif 267 } 268 break; 269 #endif 270 /* TODO add code to handle V7 MUX and Blit MUX files */ 271 #ifdef S_IFIFO 272 case S_IFIFO: 273 if((ms->flags & MAGIC_DEVICES) != 0) 274 break; 275 if (mime) { 276 if (handle_mime(ms, mime, "fifo") == -1) 277 return -1; 278 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1) 279 return -1; 280 break; 281 #endif 282 #ifdef S_IFDOOR 283 case S_IFDOOR: 284 if (mime) { 285 if (handle_mime(ms, mime, "door") == -1) 286 return -1; 287 } else if (file_printf(ms, "%sdoor", COMMA) == -1) 288 return -1; 289 break; 290 #endif 291 #ifdef S_IFLNK 292 case S_IFLNK: 293 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 294 if (ms->flags & MAGIC_ERROR) { 295 file_error(ms, errno, "unreadable symlink `%s'", 296 fn); 297 return -1; 298 } 299 if (mime) { 300 if (handle_mime(ms, mime, "symlink") == -1) 301 return -1; 302 } else if (file_printf(ms, 303 "%sunreadable symlink `%s' (%s)", COMMA, fn, 304 strerror(errno)) == -1) 305 return -1; 306 break; 307 } 308 buf[nch] = '\0'; /* readlink(2) does not do this */ 309 310 /* If broken symlink, say so and quit early. */ 311 if (*buf == '/') { 312 if (stat(buf, &tstatbuf) < 0) 313 return bad_link(ms, errno, buf); 314 } else { 315 char *tmp; 316 char buf2[BUFSIZ+BUFSIZ+4]; 317 318 if ((tmp = strrchr(fn, '/')) == NULL) { 319 tmp = buf; /* in current directory anyway */ 320 } else { 321 if (tmp - fn + 1 > BUFSIZ) { 322 if (ms->flags & MAGIC_ERROR) { 323 file_error(ms, 0, 324 "path too long: `%s'", buf); 325 return -1; 326 } 327 if (mime) { 328 if (handle_mime(ms, mime, 329 "x-path-too-long") == -1) 330 return -1; 331 } else if (file_printf(ms, 332 "%spath too long: `%s'", COMMA, 333 fn) == -1) 334 return -1; 335 break; 336 } 337 /* take dir part */ 338 (void)strlcpy(buf2, fn, sizeof buf2); 339 buf2[tmp - fn + 1] = '\0'; 340 /* plus (rel) link */ 341 (void)strlcat(buf2, buf, sizeof buf2); 342 tmp = buf2; 343 } 344 if (stat(tmp, &tstatbuf) < 0) 345 return bad_link(ms, errno, buf); 346 } 347 348 /* Otherwise, handle it. */ 349 if ((ms->flags & MAGIC_SYMLINK) != 0) { 350 const char *p; 351 ms->flags &= MAGIC_SYMLINK; 352 p = magic_file(ms, buf); 353 ms->flags |= MAGIC_SYMLINK; 354 if (p == NULL) 355 return -1; 356 } else { /* just print what it points to */ 357 if (mime) { 358 if (handle_mime(ms, mime, "symlink") == -1) 359 return -1; 360 } else if (file_printf(ms, "%ssymbolic link to `%s'", 361 COMMA, buf) == -1) 362 return -1; 363 } 364 break; 365 #endif 366 #ifdef S_IFSOCK 367 #ifndef __COHERENT__ 368 case S_IFSOCK: 369 if (mime) { 370 if (handle_mime(ms, mime, "socket") == -1) 371 return -1; 372 } else if (file_printf(ms, "%ssocket", COMMA) == -1) 373 return -1; 374 break; 375 #endif 376 #endif 377 case S_IFREG: 378 /* 379 * regular file, check next possibility 380 * 381 * If stat() tells us the file has zero length, report here that 382 * the file is empty, so we can skip all the work of opening and 383 * reading the file. 384 * But if the -s option has been given, we skip this 385 * optimization, since on some systems, stat() reports zero 386 * size for raw disk partitions. (If the block special device 387 * really has zero length, the fact that it is empty will be 388 * detected and reported correctly when we read the file.) 389 */ 390 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 391 if (mime) { 392 if (handle_mime(ms, mime, "x-empty") == -1) 393 return -1; 394 } else if (file_printf(ms, "%sempty", COMMA) == -1) 395 return -1; 396 break; 397 } 398 ret = 0; 399 break; 400 401 default: 402 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 403 return -1; 404 /*NOTREACHED*/ 405 } 406 407 if (!mime && did && ret == 0) { 408 if (file_printf(ms, " ") == -1) 409 return -1; 410 } 411 return ret; 412 } 413