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 1.62 2010/09/20 20:16:08 rrt 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 const char *errfmt; 67 int mime = ms->flags & MAGIC_MIME; 68 if ((mime & MAGIC_MIME_TYPE) && 69 file_printf(ms, "application/x-symlink") 70 == -1) 71 return -1; 72 else if (!mime) { 73 if (err == ELOOP) 74 errfmt = "symbolic link in a loop"; 75 else 76 errfmt = "broken symbolic link to `%s'"; 77 if (ms->flags & MAGIC_ERROR) { 78 file_error(ms, err, errfmt, buf); 79 return -1; 80 } 81 if (file_printf(ms, errfmt, 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, "application/%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 = 0; 106 int mime = ms->flags & MAGIC_MIME; 107 #ifdef S_IFLNK 108 char buf[BUFSIZ+4]; 109 ssize_t nch; 110 struct stat tstatbuf; 111 #endif 112 113 if (ms->flags & MAGIC_APPLE) 114 return 0; 115 if (fn == NULL) 116 return 0; 117 118 /* 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 if (ret) { 130 if (ms->flags & MAGIC_ERROR) { 131 file_error(ms, errno, "cannot stat `%s'", fn); 132 return -1; 133 } 134 if (file_printf(ms, "cannot open `%s' (%s)", 135 fn, strerror(errno)) == -1) 136 return -1; 137 ms->event_flags |= EVENT_HAD_ERR; 138 return -1; 139 } 140 141 if (!mime) { 142 #ifdef S_ISUID 143 if (sb->st_mode & S_ISUID) 144 if (file_printf(ms, "setuid ") == -1) 145 return -1; 146 #endif 147 #ifdef S_ISGID 148 if (sb->st_mode & S_ISGID) 149 if (file_printf(ms, "setgid ") == -1) 150 return -1; 151 #endif 152 #ifdef S_ISVTX 153 if (sb->st_mode & S_ISVTX) 154 if (file_printf(ms, "sticky ") == -1) 155 return -1; 156 #endif 157 } 158 159 switch (sb->st_mode & S_IFMT) { 160 case S_IFDIR: 161 if (mime) { 162 if (handle_mime(ms, mime, "x-directory") == -1) 163 return -1; 164 } else if (file_printf(ms, "directory") == -1) 165 return -1; 166 return 1; 167 #ifdef S_IFCHR 168 case S_IFCHR: 169 /* 170 * If -s has been specified, treat character special files 171 * like ordinary files. Otherwise, just report that they 172 * are block special files and go on to the next file. 173 */ 174 if ((ms->flags & MAGIC_DEVICES) != 0) 175 break; 176 if (mime) { 177 if (handle_mime(ms, mime, "x-character-device") == -1) 178 return -1; 179 } else { 180 #ifdef HAVE_STAT_ST_RDEV 181 # ifdef dv_unit 182 if (file_printf(ms, "character special (%d/%d/%d)", 183 major(sb->st_rdev), dv_unit(sb->st_rdev), 184 dv_subunit(sb->st_rdev)) == -1) 185 return -1; 186 # else 187 if (file_printf(ms, "character special (%ld/%ld)", 188 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 189 == -1) 190 return -1; 191 # endif 192 #else 193 if (file_printf(ms, "character special") == -1) 194 return -1; 195 #endif 196 } 197 return 1; 198 #endif 199 #ifdef S_IFBLK 200 case S_IFBLK: 201 /* 202 * If -s has been specified, treat block special files 203 * like ordinary files. Otherwise, just report that they 204 * are block special files and go on to the next file. 205 */ 206 if ((ms->flags & MAGIC_DEVICES) != 0) 207 break; 208 if (mime) { 209 if (handle_mime(ms, mime, "x-block-device") == -1) 210 return -1; 211 } else { 212 #ifdef HAVE_STAT_ST_RDEV 213 # ifdef dv_unit 214 if (file_printf(ms, "block special (%d/%d/%d)", 215 major(sb->st_rdev), dv_unit(sb->st_rdev), 216 dv_subunit(sb->st_rdev)) == -1) 217 return -1; 218 # else 219 if (file_printf(ms, "block special (%ld/%ld)", 220 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 221 return -1; 222 # endif 223 #else 224 if (file_printf(ms, "block special") == -1) 225 return -1; 226 #endif 227 } 228 return 1; 229 #endif 230 /* TODO add code to handle V7 MUX and Blit MUX files */ 231 #ifdef S_IFIFO 232 case S_IFIFO: 233 if((ms->flags & MAGIC_DEVICES) != 0) 234 break; 235 if (mime) { 236 if (handle_mime(ms, mime, "x-fifo") == -1) 237 return -1; 238 } else if (file_printf(ms, "fifo (named pipe)") == -1) 239 return -1; 240 return 1; 241 #endif 242 #ifdef S_IFDOOR 243 case S_IFDOOR: 244 if (mime) { 245 if (handle_mime(ms, mime, "x-door") == -1) 246 return -1; 247 } else if (file_printf(ms, "door") == -1) 248 return -1; 249 return 1; 250 #endif 251 #ifdef S_IFLNK 252 case S_IFLNK: 253 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 254 if (ms->flags & MAGIC_ERROR) { 255 file_error(ms, errno, "unreadable symlink `%s'", 256 fn); 257 return -1; 258 } 259 if (mime) { 260 if (handle_mime(ms, mime, "x-symlink") == -1) 261 return -1; 262 } else if (file_printf(ms, 263 "unreadable symlink `%s' (%s)", fn, 264 strerror(errno)) == -1) 265 return -1; 266 return 1; 267 } 268 buf[nch] = '\0'; /* readlink(2) does not do this */ 269 270 /* If broken symlink, say so and quit early. */ 271 if (*buf == '/') { 272 if (stat(buf, &tstatbuf) < 0) 273 return bad_link(ms, errno, buf); 274 } else { 275 char *tmp; 276 char buf2[BUFSIZ+BUFSIZ+4]; 277 278 if ((tmp = strrchr(fn, '/')) == NULL) { 279 tmp = buf; /* in current directory anyway */ 280 } else { 281 if (tmp - fn + 1 > BUFSIZ) { 282 if (ms->flags & MAGIC_ERROR) { 283 file_error(ms, 0, 284 "path too long: `%s'", buf); 285 return -1; 286 } 287 if (mime) { 288 if (handle_mime(ms, mime, 289 "x-path-too-long") == -1) 290 return -1; 291 } else if (file_printf(ms, 292 "path too long: `%s'", fn) == -1) 293 return -1; 294 return 1; 295 } 296 /* take dir part */ 297 (void)strlcpy(buf2, fn, sizeof buf2); 298 buf2[tmp - fn + 1] = '\0'; 299 /* plus (rel) link */ 300 (void)strlcat(buf2, buf, sizeof buf2); 301 tmp = buf2; 302 } 303 if (stat(tmp, &tstatbuf) < 0) 304 return bad_link(ms, errno, buf); 305 } 306 307 /* Otherwise, handle it. */ 308 if ((ms->flags & MAGIC_SYMLINK) != 0) { 309 const char *p; 310 ms->flags &= MAGIC_SYMLINK; 311 p = magic_file(ms, buf); 312 ms->flags |= MAGIC_SYMLINK; 313 return p != NULL ? 1 : -1; 314 } else { /* just print what it points to */ 315 if (mime) { 316 if (handle_mime(ms, mime, "x-symlink") == -1) 317 return -1; 318 } else if (file_printf(ms, "symbolic link to `%s'", 319 buf) == -1) 320 return -1; 321 } 322 return 1; 323 #endif 324 #ifdef S_IFSOCK 325 #ifndef __COHERENT__ 326 case S_IFSOCK: 327 if (mime) { 328 if (handle_mime(ms, mime, "x-socket") == -1) 329 return -1; 330 } else if (file_printf(ms, "socket") == -1) 331 return -1; 332 return 1; 333 #endif 334 #endif 335 case S_IFREG: 336 break; 337 default: 338 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 339 return -1; 340 /*NOTREACHED*/ 341 } 342 343 /* 344 * regular file, check next possibility 345 * 346 * If stat() tells us the file has zero length, report here that 347 * the file is empty, so we can skip all the work of opening and 348 * reading the file. 349 * But if the -s option has been given, we skip this optimization, 350 * since on some systems, stat() reports zero size for raw disk 351 * partitions. (If the block special device really has zero length, 352 * the fact that it is empty will be detected and reported correctly 353 * when we read the file.) 354 */ 355 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 356 if (mime) { 357 if (handle_mime(ms, mime, "x-empty") == -1) 358 return -1; 359 } else if (file_printf(ms, "empty") == -1) 360 return -1; 361 return 1; 362 } 363 return 0; 364 } 365