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 1.71 2013/12/01 18:01:07 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 57 #ifndef HAVE_MAJOR 58 # define major(dev) (((dev) >> 8) & 0xff) 59 # define minor(dev) ((dev) & 0xff) 60 #endif 61 #undef HAVE_MAJOR 62 #ifdef S_IFLNK 63 private int 64 bad_link(struct magic_set *ms, int err, char *buf) 65 { 66 int mime = ms->flags & MAGIC_MIME; 67 if ((mime & MAGIC_MIME_TYPE) && 68 file_printf(ms, "inode/symlink") 69 == -1) 70 return -1; 71 else if (!mime) { 72 if (ms->flags & MAGIC_ERROR) { 73 file_error(ms, err, 74 "broken symbolic link to `%s'", buf); 75 return -1; 76 } 77 if (file_printf(ms, "broken symbolic link to `%s'", buf) == -1) 78 return -1; 79 } 80 return 1; 81 } 82 #endif 83 private int 84 handle_mime(struct magic_set *ms, int mime, const char *str) 85 { 86 if ((mime & MAGIC_MIME_TYPE)) { 87 if (file_printf(ms, "inode/%s", str) == -1) 88 return -1; 89 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 90 "; charset=") == -1) 91 return -1; 92 } 93 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 94 return -1; 95 return 0; 96 } 97 98 protected int 99 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 100 { 101 int ret, did = 0; 102 int mime = ms->flags & MAGIC_MIME; 103 #ifdef S_IFLNK 104 char buf[BUFSIZ+4]; 105 ssize_t nch; 106 struct stat tstatbuf; 107 #endif 108 109 if (ms->flags & MAGIC_APPLE) 110 return 0; 111 if (fn == NULL) 112 return 0; 113 114 #define COMMA (did++ ? ", " : "") 115 /* 116 * Fstat is cheaper but fails for files you don't have read perms on. 117 * On 4.2BSD and similar systems, use lstat() to identify symlinks. 118 */ 119 #ifdef S_IFLNK 120 if ((ms->flags & MAGIC_SYMLINK) == 0) 121 ret = lstat(fn, sb); 122 else 123 #endif 124 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 125 126 if (ret) { 127 if (ms->flags & MAGIC_ERROR) { 128 file_error(ms, errno, "cannot stat `%s'", fn); 129 return -1; 130 } 131 if (file_printf(ms, "cannot open `%s' (%s)", 132 fn, strerror(errno)) == -1) 133 return -1; 134 return 0; 135 } 136 137 ret = 1; 138 if (!mime) { 139 #ifdef S_ISUID 140 if (sb->st_mode & S_ISUID) 141 if (file_printf(ms, "%ssetuid", COMMA) == -1) 142 return -1; 143 #endif 144 #ifdef S_ISGID 145 if (sb->st_mode & S_ISGID) 146 if (file_printf(ms, "%ssetgid", COMMA) == -1) 147 return -1; 148 #endif 149 #ifdef S_ISVTX 150 if (sb->st_mode & S_ISVTX) 151 if (file_printf(ms, "%ssticky", COMMA) == -1) 152 return -1; 153 #endif 154 } 155 156 switch (sb->st_mode & S_IFMT) { 157 case S_IFDIR: 158 if (mime) { 159 if (handle_mime(ms, mime, "directory") == -1) 160 return -1; 161 } else if (file_printf(ms, "%sdirectory", COMMA) == -1) 162 return -1; 163 break; 164 #ifdef S_IFCHR 165 case S_IFCHR: 166 /* 167 * If -s has been specified, treat character special files 168 * like ordinary files. Otherwise, just report that they 169 * are block special files and go on to the next file. 170 */ 171 if ((ms->flags & MAGIC_DEVICES) != 0) { 172 ret = 0; 173 break; 174 } 175 if (mime) { 176 if (handle_mime(ms, mime, "chardevice") == -1) 177 return -1; 178 } else { 179 #ifdef HAVE_STAT_ST_RDEV 180 # ifdef dv_unit 181 if (file_printf(ms, "%scharacter special (%d/%d/%d)", 182 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 183 dv_subunit(sb->st_rdev)) == -1) 184 return -1; 185 # else 186 if (file_printf(ms, "%scharacter special (%ld/%ld)", 187 COMMA, (long)major(sb->st_rdev), 188 (long)minor(sb->st_rdev)) == -1) 189 return -1; 190 # endif 191 #else 192 if (file_printf(ms, "%scharacter special", COMMA) == -1) 193 return -1; 194 #endif 195 } 196 break; 197 #endif 198 #ifdef S_IFBLK 199 case S_IFBLK: 200 /* 201 * If -s has been specified, treat block special files 202 * like ordinary files. Otherwise, just report that they 203 * are block special files and go on to the next file. 204 */ 205 if ((ms->flags & MAGIC_DEVICES) != 0) { 206 ret = 0; 207 break; 208 } 209 if (mime) { 210 if (handle_mime(ms, mime, "blockdevice") == -1) 211 return -1; 212 } else { 213 #ifdef HAVE_STAT_ST_RDEV 214 # ifdef dv_unit 215 if (file_printf(ms, "%sblock 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, "%sblock 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, "%sblock special", COMMA) == -1) 227 return -1; 228 #endif 229 } 230 break; 231 #endif 232 /* TODO add code to handle V7 MUX and Blit MUX files */ 233 #ifdef S_IFIFO 234 case S_IFIFO: 235 if((ms->flags & MAGIC_DEVICES) != 0) 236 break; 237 if (mime) { 238 if (handle_mime(ms, mime, "fifo") == -1) 239 return -1; 240 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1) 241 return -1; 242 break; 243 #endif 244 #ifdef S_IFDOOR 245 case S_IFDOOR: 246 if (mime) { 247 if (handle_mime(ms, mime, "door") == -1) 248 return -1; 249 } else if (file_printf(ms, "%sdoor", COMMA) == -1) 250 return -1; 251 break; 252 #endif 253 #ifdef S_IFLNK 254 case S_IFLNK: 255 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 256 if (ms->flags & MAGIC_ERROR) { 257 file_error(ms, errno, "unreadable symlink `%s'", 258 fn); 259 return -1; 260 } 261 if (mime) { 262 if (handle_mime(ms, mime, "symlink") == -1) 263 return -1; 264 } else if (file_printf(ms, 265 "%sunreadable symlink `%s' (%s)", COMMA, fn, 266 strerror(errno)) == -1) 267 return -1; 268 break; 269 } 270 buf[nch] = '\0'; /* readlink(2) does not do this */ 271 272 /* If broken symlink, say so and quit early. */ 273 if (*buf == '/') { 274 if (stat(buf, &tstatbuf) < 0) 275 return bad_link(ms, errno, buf); 276 } else { 277 char *tmp; 278 char buf2[BUFSIZ+BUFSIZ+4]; 279 280 if ((tmp = strrchr(fn, '/')) == NULL) { 281 tmp = buf; /* in current directory anyway */ 282 } else { 283 if (tmp - fn + 1 > BUFSIZ) { 284 if (ms->flags & MAGIC_ERROR) { 285 file_error(ms, 0, 286 "path too long: `%s'", buf); 287 return -1; 288 } 289 if (mime) { 290 if (handle_mime(ms, mime, 291 "x-path-too-long") == -1) 292 return -1; 293 } else if (file_printf(ms, 294 "%spath too long: `%s'", COMMA, 295 fn) == -1) 296 return -1; 297 break; 298 } 299 /* take dir part */ 300 (void)strlcpy(buf2, fn, sizeof buf2); 301 buf2[tmp - fn + 1] = '\0'; 302 /* plus (rel) link */ 303 (void)strlcat(buf2, buf, sizeof buf2); 304 tmp = buf2; 305 } 306 if (stat(tmp, &tstatbuf) < 0) 307 return bad_link(ms, errno, buf); 308 } 309 310 /* Otherwise, handle it. */ 311 if ((ms->flags & MAGIC_SYMLINK) != 0) { 312 const char *p; 313 ms->flags &= MAGIC_SYMLINK; 314 p = magic_file(ms, buf); 315 ms->flags |= MAGIC_SYMLINK; 316 if (p == NULL) 317 return -1; 318 } else { /* just print what it points to */ 319 if (mime) { 320 if (handle_mime(ms, mime, "symlink") == -1) 321 return -1; 322 } else if (file_printf(ms, "%ssymbolic link to `%s'", 323 COMMA, buf) == -1) 324 return -1; 325 } 326 break; 327 #endif 328 #ifdef S_IFSOCK 329 #ifndef __COHERENT__ 330 case S_IFSOCK: 331 if (mime) { 332 if (handle_mime(ms, mime, "socket") == -1) 333 return -1; 334 } else if (file_printf(ms, "%ssocket", COMMA) == -1) 335 return -1; 336 break; 337 #endif 338 #endif 339 case S_IFREG: 340 /* 341 * regular file, check next possibility 342 * 343 * If stat() tells us the file has zero length, report here that 344 * the file is empty, so we can skip all the work of opening and 345 * reading the file. 346 * But if the -s option has been given, we skip this 347 * optimization, since on some systems, stat() reports zero 348 * size for raw disk partitions. (If the block special device 349 * really has zero length, the fact that it is empty will be 350 * detected and reported correctly when we read the file.) 351 */ 352 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 353 if (mime) { 354 if (handle_mime(ms, mime, "x-empty") == -1) 355 return -1; 356 } else if (file_printf(ms, "%sempty", COMMA) == -1) 357 return -1; 358 break; 359 } 360 ret = 0; 361 break; 362 363 default: 364 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 365 return -1; 366 /*NOTREACHED*/ 367 } 368 369 if (!mime && did && ret == 0) { 370 if (file_printf(ms, " ") == -1) 371 return -1; 372 } 373 return ret; 374 } 375