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 1.59 2009/02/03 20:27:51 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 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 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 int 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 return 1; 138 } 139 140 if (!mime) { 141 #ifdef S_ISUID 142 if (sb->st_mode & S_ISUID) 143 if (file_printf(ms, "setuid ") == -1) 144 return -1; 145 #endif 146 #ifdef S_ISGID 147 if (sb->st_mode & S_ISGID) 148 if (file_printf(ms, "setgid ") == -1) 149 return -1; 150 #endif 151 #ifdef S_ISVTX 152 if (sb->st_mode & S_ISVTX) 153 if (file_printf(ms, "sticky ") == -1) 154 return -1; 155 #endif 156 } 157 158 switch (sb->st_mode & S_IFMT) { 159 case S_IFDIR: 160 if (mime) { 161 if (handle_mime(ms, mime, "x-directory") == -1) 162 return -1; 163 } else if (file_printf(ms, "directory") == -1) 164 return -1; 165 return 1; 166 #ifdef S_IFCHR 167 case S_IFCHR: 168 /* 169 * If -s has been specified, treat character special files 170 * like ordinary files. Otherwise, just report that they 171 * are block special files and go on to the next file. 172 */ 173 if ((ms->flags & MAGIC_DEVICES) != 0) 174 break; 175 if (mime) { 176 if (handle_mime(ms, mime, "x-character-device") == -1) 177 return -1; 178 } else { 179 #ifdef HAVE_STAT_ST_RDEV 180 # ifdef dv_unit 181 if (file_printf(ms, "character special (%d/%d/%d)", 182 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, "character special (%ld/%ld)", 187 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 188 == -1) 189 return -1; 190 # endif 191 #else 192 if (file_printf(ms, "character special") == -1) 193 return -1; 194 #endif 195 } 196 return 1; 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 break; 207 if (mime) { 208 if (handle_mime(ms, mime, "x-block-device") == -1) 209 return -1; 210 } else { 211 #ifdef HAVE_STAT_ST_RDEV 212 # ifdef dv_unit 213 if (file_printf(ms, "block special (%d/%d/%d)", 214 major(sb->st_rdev), dv_unit(sb->st_rdev), 215 dv_subunit(sb->st_rdev)) == -1) 216 return -1; 217 # else 218 if (file_printf(ms, "block special (%ld/%ld)", 219 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 220 return -1; 221 # endif 222 #else 223 if (file_printf(ms, "block special") == -1) 224 return -1; 225 #endif 226 } 227 return 1; 228 #endif 229 /* TODO add code to handle V7 MUX and Blit MUX files */ 230 #ifdef S_IFIFO 231 case S_IFIFO: 232 if((ms->flags & MAGIC_DEVICES) != 0) 233 break; 234 if (mime) { 235 if (handle_mime(ms, mime, "x-fifo") == -1) 236 return -1; 237 } else if (file_printf(ms, "fifo (named pipe)") == -1) 238 return -1; 239 return 1; 240 #endif 241 #ifdef S_IFDOOR 242 case S_IFDOOR: 243 if (mime) { 244 if (handle_mime(ms, mime, "x-door") == -1) 245 return -1; 246 } else if (file_printf(ms, "door") == -1) 247 return -1; 248 return 1; 249 #endif 250 #ifdef S_IFLNK 251 case S_IFLNK: 252 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 253 if (ms->flags & MAGIC_ERROR) { 254 file_error(ms, errno, "unreadable symlink `%s'", 255 fn); 256 return -1; 257 } 258 if (mime) { 259 if (handle_mime(ms, mime, "x-symlink") == -1) 260 return -1; 261 } else if (file_printf(ms, 262 "unreadable symlink `%s' (%s)", fn, 263 strerror(errno)) == -1) 264 return -1; 265 return 1; 266 } 267 buf[nch] = '\0'; /* readlink(2) does not do this */ 268 269 /* If broken symlink, say so and quit early. */ 270 if (*buf == '/') { 271 if (stat(buf, &tstatbuf) < 0) 272 return bad_link(ms, errno, buf); 273 } else { 274 char *tmp; 275 char buf2[BUFSIZ+BUFSIZ+4]; 276 277 if ((tmp = strrchr(fn, '/')) == NULL) { 278 tmp = buf; /* in current directory anyway */ 279 } else { 280 if (tmp - fn + 1 > BUFSIZ) { 281 if (ms->flags & MAGIC_ERROR) { 282 file_error(ms, 0, 283 "path too long: `%s'", buf); 284 return -1; 285 } 286 if (mime) { 287 if (handle_mime(ms, mime, 288 "x-path-too-long") == -1) 289 return -1; 290 } else if (file_printf(ms, 291 "path too long: `%s'", fn) == -1) 292 return -1; 293 return 1; 294 } 295 /* take dir part */ 296 (void)strlcpy(buf2, fn, sizeof buf2); 297 buf2[tmp - fn + 1] = '\0'; 298 /* plus (rel) link */ 299 (void)strlcat(buf2, buf, sizeof buf2); 300 tmp = buf2; 301 } 302 if (stat(tmp, &tstatbuf) < 0) 303 return bad_link(ms, errno, buf); 304 } 305 306 /* Otherwise, handle it. */ 307 if ((ms->flags & MAGIC_SYMLINK) != 0) { 308 const char *p; 309 ms->flags &= MAGIC_SYMLINK; 310 p = magic_file(ms, buf); 311 ms->flags |= MAGIC_SYMLINK; 312 return p != NULL ? 1 : -1; 313 } else { /* just print what it points to */ 314 if (mime) { 315 if (handle_mime(ms, mime, "x-symlink") == -1) 316 return -1; 317 } else if (file_printf(ms, "symbolic link to `%s'", 318 buf) == -1) 319 return -1; 320 } 321 return 1; 322 #endif 323 #ifdef S_IFSOCK 324 #ifndef __COHERENT__ 325 case S_IFSOCK: 326 if (mime) { 327 if (handle_mime(ms, mime, "x-socket") == -1) 328 return -1; 329 } else if (file_printf(ms, "socket") == -1) 330 return -1; 331 return 1; 332 #endif 333 #endif 334 case S_IFREG: 335 break; 336 default: 337 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 338 return -1; 339 /*NOTREACHED*/ 340 } 341 342 /* 343 * regular file, check next possibility 344 * 345 * If stat() tells us the file has zero length, report here that 346 * the file is empty, so we can skip all the work of opening and 347 * reading the file. 348 * But if the -s option has been given, we skip this optimization, 349 * since on some systems, stat() reports zero size for raw disk 350 * partitions. (If the block special device really has zero length, 351 * the fact that it is empty will be detected and reported correctly 352 * when we read the file.) 353 */ 354 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 355 if (mime) { 356 if (handle_mime(ms, mime, "x-empty") == -1) 357 return -1; 358 } else if (file_printf(ms, "empty") == -1) 359 return -1; 360 return 1; 361 } 362 return 0; 363 } 364