1 /* 2 * Copyright (c) Ian F. Darwin 1986-1995. 3 * Software written by Ian F. Darwin and others; 4 * maintained 1995-present by Christos Zoulas and others. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice immediately at the beginning of the file, without modification, 11 * this list of conditions, and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * fsmagic - magic based on filesystem info - directory, special files, etc. 30 */ 31 32 #include "file.h" 33 34 #ifndef lint 35 FILE_RCSID("@(#)$File: fsmagic.c,v 1.77 2017/05/24 19:17:50 christos Exp $") 36 #endif /* lint */ 37 38 #include "magic.h" 39 #include <string.h> 40 #ifdef HAVE_UNISTD_H 41 #include <unistd.h> 42 #endif 43 #include <stdlib.h> 44 /* Since major is a function on SVR4, we cannot use `ifndef major'. */ 45 #ifdef MAJOR_IN_MKDEV 46 # include <sys/mkdev.h> 47 # define HAVE_MAJOR 48 #endif 49 #ifdef MAJOR_IN_SYSMACROS 50 # include <sys/sysmacros.h> 51 # define HAVE_MAJOR 52 #endif 53 #ifdef major /* Might be defined in sys/types.h. */ 54 # define HAVE_MAJOR 55 #endif 56 #ifdef WIN32 57 # define WIN32_LEAN_AND_MEAN 58 # include <windows.h> 59 #endif 60 61 #ifndef HAVE_MAJOR 62 # define major(dev) (((dev) >> 8) & 0xff) 63 # define minor(dev) ((dev) & 0xff) 64 #endif 65 #undef HAVE_MAJOR 66 #ifdef S_IFLNK 67 private int 68 bad_link(struct magic_set *ms, int err, char *buf) 69 { 70 int mime = ms->flags & MAGIC_MIME; 71 if ((mime & MAGIC_MIME_TYPE) && 72 file_printf(ms, "inode/symlink") 73 == -1) 74 return -1; 75 else if (!mime) { 76 if (ms->flags & MAGIC_ERROR) { 77 file_error(ms, err, 78 "broken symbolic link to %s", buf); 79 return -1; 80 } 81 if (file_printf(ms, "broken symbolic link to %s", buf) == -1) 82 return -1; 83 } 84 return 1; 85 } 86 #endif 87 private int 88 handle_mime(struct magic_set *ms, int mime, const char *str) 89 { 90 if ((mime & MAGIC_MIME_TYPE)) { 91 if (file_printf(ms, "inode/%s", str) == -1) 92 return -1; 93 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 94 "; charset=") == -1) 95 return -1; 96 } 97 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 98 return -1; 99 return 0; 100 } 101 102 protected int 103 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 104 { 105 int ret, did = 0; 106 int mime = ms->flags & MAGIC_MIME; 107 int silent = ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION); 108 #ifdef S_IFLNK 109 char buf[BUFSIZ+4]; 110 ssize_t nch; 111 struct stat tstatbuf; 112 #endif 113 114 if (fn == NULL) 115 return 0; 116 117 #define COMMA (did++ ? ", " : "") 118 /* 119 * Fstat is cheaper but fails for files you don't have read perms on. 120 * On 4.2BSD and similar systems, use lstat() to identify symlinks. 121 */ 122 #ifdef S_IFLNK 123 if ((ms->flags & MAGIC_SYMLINK) == 0) 124 ret = lstat(fn, sb); 125 else 126 #endif 127 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 128 129 #ifdef WIN32 130 { 131 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE | 132 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, 133 NULL); 134 if (hFile != INVALID_HANDLE_VALUE) { 135 /* 136 * Stat failed, but we can still open it - assume it's 137 * a block device, if nothing else. 138 */ 139 if (ret) { 140 sb->st_mode = S_IFBLK; 141 ret = 0; 142 } 143 switch (GetFileType(hFile)) { 144 case FILE_TYPE_CHAR: 145 sb->st_mode |= S_IFCHR; 146 sb->st_mode &= ~S_IFREG; 147 break; 148 case FILE_TYPE_PIPE: 149 sb->st_mode |= S_IFIFO; 150 sb->st_mode &= ~S_IFREG; 151 break; 152 } 153 CloseHandle(hFile); 154 } 155 } 156 #endif 157 158 if (ret) { 159 if (ms->flags & MAGIC_ERROR) { 160 file_error(ms, errno, "cannot stat `%s'", fn); 161 return -1; 162 } 163 if (file_printf(ms, "cannot open `%s' (%s)", 164 fn, strerror(errno)) == -1) 165 return -1; 166 return 0; 167 } 168 169 ret = 1; 170 if (!mime && !silent) { 171 #ifdef S_ISUID 172 if (sb->st_mode & S_ISUID) 173 if (file_printf(ms, "%ssetuid", COMMA) == -1) 174 return -1; 175 #endif 176 #ifdef S_ISGID 177 if (sb->st_mode & S_ISGID) 178 if (file_printf(ms, "%ssetgid", COMMA) == -1) 179 return -1; 180 #endif 181 #ifdef S_ISVTX 182 if (sb->st_mode & S_ISVTX) 183 if (file_printf(ms, "%ssticky", COMMA) == -1) 184 return -1; 185 #endif 186 } 187 188 switch (sb->st_mode & S_IFMT) { 189 case S_IFDIR: 190 if (mime) { 191 if (handle_mime(ms, mime, "directory") == -1) 192 return -1; 193 } else if (silent) { 194 } else if (file_printf(ms, "%sdirectory", COMMA) == -1) 195 return -1; 196 break; 197 #ifdef S_IFCHR 198 case S_IFCHR: 199 /* 200 * If -s has been specified, treat character special files 201 * like ordinary files. Otherwise, just report that they 202 * are block special files and go on to the next file. 203 */ 204 if ((ms->flags & MAGIC_DEVICES) != 0) { 205 ret = 0; 206 break; 207 } 208 if (mime) { 209 if (handle_mime(ms, mime, "chardevice") == -1) 210 return -1; 211 } else if (silent) { 212 } else { 213 #ifdef HAVE_STRUCT_STAT_ST_RDEV 214 # ifdef dv_unit 215 if (file_printf(ms, "%scharacter special (%d/%d/%d)", 216 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 217 dv_subunit(sb->st_rdev)) == -1) 218 return -1; 219 # else 220 if (file_printf(ms, "%scharacter special (%ld/%ld)", 221 COMMA, (long)major(sb->st_rdev), 222 (long)minor(sb->st_rdev)) == -1) 223 return -1; 224 # endif 225 #else 226 if (file_printf(ms, "%scharacter special", COMMA) == -1) 227 return -1; 228 #endif 229 } 230 break; 231 #endif 232 #ifdef S_IFBLK 233 case S_IFBLK: 234 /* 235 * If -s has been specified, treat block special files 236 * like ordinary files. Otherwise, just report that they 237 * are block special files and go on to the next file. 238 */ 239 if ((ms->flags & MAGIC_DEVICES) != 0) { 240 ret = 0; 241 break; 242 } 243 if (mime) { 244 if (handle_mime(ms, mime, "blockdevice") == -1) 245 return -1; 246 } else if (silent) { 247 } else { 248 #ifdef HAVE_STRUCT_STAT_ST_RDEV 249 # ifdef dv_unit 250 if (file_printf(ms, "%sblock special (%d/%d/%d)", 251 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 252 dv_subunit(sb->st_rdev)) == -1) 253 return -1; 254 # else 255 if (file_printf(ms, "%sblock special (%ld/%ld)", 256 COMMA, (long)major(sb->st_rdev), 257 (long)minor(sb->st_rdev)) == -1) 258 return -1; 259 # endif 260 #else 261 if (file_printf(ms, "%sblock special", COMMA) == -1) 262 return -1; 263 #endif 264 } 265 break; 266 #endif 267 /* TODO add code to handle V7 MUX and Blit MUX files */ 268 #ifdef S_IFIFO 269 case S_IFIFO: 270 if((ms->flags & MAGIC_DEVICES) != 0) 271 break; 272 if (mime) { 273 if (handle_mime(ms, mime, "fifo") == -1) 274 return -1; 275 } else if (silent) { 276 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1) 277 return -1; 278 break; 279 #endif 280 #ifdef S_IFDOOR 281 case S_IFDOOR: 282 if (mime) { 283 if (handle_mime(ms, mime, "door") == -1) 284 return -1; 285 } else if (silent) { 286 } else if (file_printf(ms, "%sdoor", COMMA) == -1) 287 return -1; 288 break; 289 #endif 290 #ifdef S_IFLNK 291 case S_IFLNK: 292 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 293 if (ms->flags & MAGIC_ERROR) { 294 file_error(ms, errno, "unreadable symlink `%s'", 295 fn); 296 return -1; 297 } 298 if (mime) { 299 if (handle_mime(ms, mime, "symlink") == -1) 300 return -1; 301 } else if (silent) { 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 (silent) { 332 } else if (file_printf(ms, 333 "%spath too long: `%s'", COMMA, 334 fn) == -1) 335 return -1; 336 break; 337 } 338 /* take dir part */ 339 (void)strlcpy(buf2, fn, sizeof buf2); 340 buf2[tmp - fn + 1] = '\0'; 341 /* plus (rel) link */ 342 (void)strlcat(buf2, buf, sizeof buf2); 343 tmp = buf2; 344 } 345 if (stat(tmp, &tstatbuf) < 0) 346 return bad_link(ms, errno, buf); 347 } 348 349 /* Otherwise, handle it. */ 350 if ((ms->flags & MAGIC_SYMLINK) != 0) { 351 const char *p; 352 ms->flags &= MAGIC_SYMLINK; 353 p = magic_file(ms, buf); 354 ms->flags |= MAGIC_SYMLINK; 355 if (p == NULL) 356 return -1; 357 } else { /* just print what it points to */ 358 if (mime) { 359 if (handle_mime(ms, mime, "symlink") == -1) 360 return -1; 361 } else if (silent) { 362 } else if (file_printf(ms, "%ssymbolic link to %s", 363 COMMA, buf) == -1) 364 return -1; 365 } 366 break; 367 #endif 368 #ifdef S_IFSOCK 369 #ifndef __COHERENT__ 370 case S_IFSOCK: 371 if (mime) { 372 if (handle_mime(ms, mime, "socket") == -1) 373 return -1; 374 } else if (silent) { 375 } else if (file_printf(ms, "%ssocket", COMMA) == -1) 376 return -1; 377 break; 378 #endif 379 #endif 380 case S_IFREG: 381 /* 382 * regular file, check next possibility 383 * 384 * If stat() tells us the file has zero length, report here that 385 * the file is empty, so we can skip all the work of opening and 386 * reading the file. 387 * But if the -s option has been given, we skip this 388 * optimization, since on some systems, stat() reports zero 389 * size for raw disk partitions. (If the block special device 390 * really has zero length, the fact that it is empty will be 391 * detected and reported correctly when we read the file.) 392 */ 393 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 394 if (mime) { 395 if (handle_mime(ms, mime, "x-empty") == -1) 396 return -1; 397 } else if (silent) { 398 } else if (file_printf(ms, "%sempty", COMMA) == -1) 399 return -1; 400 break; 401 } 402 ret = 0; 403 break; 404 405 default: 406 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 407 return -1; 408 /*NOTREACHED*/ 409 } 410 411 if (!silent && !mime && did && ret == 0) { 412 if (file_printf(ms, " ") == -1) 413 return -1; 414 } 415 return ret; 416 } 417