1 /* $NetBSD: fsmagic.c,v 1.3 2011/05/13 01:52:13 christos Exp $ */ 2 3 /* 4 * Copyright (c) Ian F. Darwin 1986-1995. 5 * Software written by Ian F. Darwin and others; 6 * maintained 1995-present by Christos Zoulas and others. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice immediately at the beginning of the file, without modification, 13 * this list of conditions, and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 /* 31 * fsmagic - magic based on filesystem info - directory, special files, etc. 32 */ 33 34 #include "file.h" 35 36 #ifndef lint 37 #if 0 38 FILE_RCSID("@(#)$File: fsmagic.c,v 1.62 2010/09/20 20:16:08 rrt Exp $") 39 #else 40 __RCSID("$NetBSD: fsmagic.c,v 1.3 2011/05/13 01:52:13 christos Exp $"); 41 #endif 42 #endif /* lint */ 43 44 #include "magic.h" 45 #include <string.h> 46 #ifdef HAVE_UNISTD_H 47 #include <unistd.h> 48 #endif 49 #include <stdlib.h> 50 /* Since major is a function on SVR4, we cannot use `ifndef major'. */ 51 #ifdef MAJOR_IN_MKDEV 52 # include <sys/mkdev.h> 53 # define HAVE_MAJOR 54 #endif 55 #ifdef MAJOR_IN_SYSMACROS 56 # include <sys/sysmacros.h> 57 # define HAVE_MAJOR 58 #endif 59 #ifdef major /* Might be defined in sys/types.h. */ 60 # define HAVE_MAJOR 61 #endif 62 63 #ifndef HAVE_MAJOR 64 # define major(dev) (((dev) >> 8) & 0xff) 65 # define minor(dev) ((dev) & 0xff) 66 #endif 67 #undef HAVE_MAJOR 68 #ifdef S_IFLNK 69 private int 70 bad_link(struct magic_set *ms, int err, char *buf) 71 { 72 const char *errfmt; 73 int mime = ms->flags & MAGIC_MIME; 74 if ((mime & MAGIC_MIME_TYPE) && 75 file_printf(ms, "application/x-symlink") 76 == -1) 77 return -1; 78 else if (!mime) { 79 if (err == ELOOP) 80 errfmt = "symbolic link in a loop"; 81 else 82 errfmt = "broken symbolic link to `%s'"; 83 if (ms->flags & MAGIC_ERROR) { 84 file_error(ms, err, errfmt, buf); 85 return -1; 86 } 87 if (file_printf(ms, errfmt, buf) == -1) 88 return -1; 89 } 90 return 1; 91 } 92 #endif 93 private int 94 handle_mime(struct magic_set *ms, int mime, const char *str) 95 { 96 if ((mime & MAGIC_MIME_TYPE)) { 97 if (file_printf(ms, "application/%s", str) == -1) 98 return -1; 99 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 100 "; charset=") == -1) 101 return -1; 102 } 103 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 104 return -1; 105 return 0; 106 } 107 108 protected int 109 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 110 { 111 int ret = 0; 112 int mime = ms->flags & MAGIC_MIME; 113 #ifdef S_IFLNK 114 char buf[BUFSIZ+4]; 115 ssize_t nch; 116 struct stat tstatbuf; 117 #endif 118 119 if (ms->flags & MAGIC_APPLE) 120 return 0; 121 if (fn == NULL) 122 return 0; 123 124 /* 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 if (ret) { 136 if (ms->flags & MAGIC_ERROR) { 137 file_error(ms, errno, "cannot stat `%s'", fn); 138 return -1; 139 } 140 if (file_printf(ms, "cannot open `%s' (%s)", 141 fn, strerror(errno)) == -1) 142 return -1; 143 ms->event_flags |= EVENT_HAD_ERR; 144 return -1; 145 } 146 147 if (!mime) { 148 #ifdef S_ISUID 149 if (sb->st_mode & S_ISUID) 150 if (file_printf(ms, "setuid ") == -1) 151 return -1; 152 #endif 153 #ifdef S_ISGID 154 if (sb->st_mode & S_ISGID) 155 if (file_printf(ms, "setgid ") == -1) 156 return -1; 157 #endif 158 #ifdef S_ISVTX 159 if (sb->st_mode & S_ISVTX) 160 if (file_printf(ms, "sticky ") == -1) 161 return -1; 162 #endif 163 } 164 165 switch (sb->st_mode & S_IFMT) { 166 case S_IFDIR: 167 if (mime) { 168 if (handle_mime(ms, mime, "x-directory") == -1) 169 return -1; 170 } else if (file_printf(ms, "directory") == -1) 171 return -1; 172 return 1; 173 #ifdef S_IFCHR 174 case S_IFCHR: 175 /* 176 * If -s has been specified, treat character special files 177 * like ordinary files. Otherwise, just report that they 178 * are block special files and go on to the next file. 179 */ 180 if ((ms->flags & MAGIC_DEVICES) != 0) 181 break; 182 if (mime) { 183 if (handle_mime(ms, mime, "x-character-device") == -1) 184 return -1; 185 } else { 186 #ifdef HAVE_STAT_ST_RDEV 187 # ifdef dv_unit 188 if (file_printf(ms, "character special (%d/%d/%d)", 189 major(sb->st_rdev), dv_unit(sb->st_rdev), 190 dv_subunit(sb->st_rdev)) == -1) 191 return -1; 192 # else 193 if (file_printf(ms, "character special (%ld/%ld)", 194 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 195 == -1) 196 return -1; 197 # endif 198 #else 199 if (file_printf(ms, "character special") == -1) 200 return -1; 201 #endif 202 } 203 return 1; 204 #endif 205 #ifdef S_IFBLK 206 case S_IFBLK: 207 /* 208 * If -s has been specified, treat block special files 209 * like ordinary files. Otherwise, just report that they 210 * are block special files and go on to the next file. 211 */ 212 if ((ms->flags & MAGIC_DEVICES) != 0) 213 break; 214 if (mime) { 215 if (handle_mime(ms, mime, "x-block-device") == -1) 216 return -1; 217 } else { 218 #ifdef HAVE_STAT_ST_RDEV 219 # ifdef dv_unit 220 if (file_printf(ms, "block special (%d/%d/%d)", 221 major(sb->st_rdev), dv_unit(sb->st_rdev), 222 dv_subunit(sb->st_rdev)) == -1) 223 return -1; 224 # else 225 if (file_printf(ms, "block special (%ld/%ld)", 226 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 227 return -1; 228 # endif 229 #else 230 if (file_printf(ms, "block special") == -1) 231 return -1; 232 #endif 233 } 234 return 1; 235 #endif 236 /* TODO add code to handle V7 MUX and Blit MUX files */ 237 #ifdef S_IFIFO 238 case S_IFIFO: 239 if((ms->flags & MAGIC_DEVICES) != 0) 240 break; 241 if (mime) { 242 if (handle_mime(ms, mime, "x-fifo") == -1) 243 return -1; 244 } else if (file_printf(ms, "fifo (named pipe)") == -1) 245 return -1; 246 return 1; 247 #endif 248 #ifdef S_IFDOOR 249 case S_IFDOOR: 250 if (mime) { 251 if (handle_mime(ms, mime, "x-door") == -1) 252 return -1; 253 } else if (file_printf(ms, "door") == -1) 254 return -1; 255 return 1; 256 #endif 257 #ifdef S_IFLNK 258 case S_IFLNK: 259 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 260 if (ms->flags & MAGIC_ERROR) { 261 file_error(ms, errno, "unreadable symlink `%s'", 262 fn); 263 return -1; 264 } 265 if (mime) { 266 if (handle_mime(ms, mime, "x-symlink") == -1) 267 return -1; 268 } else if (file_printf(ms, 269 "unreadable symlink `%s' (%s)", fn, 270 strerror(errno)) == -1) 271 return -1; 272 return 1; 273 } 274 buf[nch] = '\0'; /* readlink(2) does not do this */ 275 276 /* If broken symlink, say so and quit early. */ 277 if (*buf == '/') { 278 if (stat(buf, &tstatbuf) < 0) 279 return bad_link(ms, errno, buf); 280 } else { 281 char *tmp; 282 char buf2[BUFSIZ+BUFSIZ+4]; 283 284 if ((tmp = strrchr(fn, '/')) == NULL) { 285 tmp = buf; /* in current directory anyway */ 286 } else { 287 if (tmp - fn + 1 > BUFSIZ) { 288 if (ms->flags & MAGIC_ERROR) { 289 file_error(ms, 0, 290 "path too long: `%s'", buf); 291 return -1; 292 } 293 if (mime) { 294 if (handle_mime(ms, mime, 295 "x-path-too-long") == -1) 296 return -1; 297 } else if (file_printf(ms, 298 "path too long: `%s'", fn) == -1) 299 return -1; 300 return 1; 301 } 302 /* take dir part */ 303 (void)strlcpy(buf2, fn, sizeof buf2); 304 buf2[tmp - fn + 1] = '\0'; 305 /* plus (rel) link */ 306 (void)strlcat(buf2, buf, sizeof buf2); 307 tmp = buf2; 308 } 309 if (stat(tmp, &tstatbuf) < 0) 310 return bad_link(ms, errno, buf); 311 } 312 313 /* Otherwise, handle it. */ 314 if ((ms->flags & MAGIC_SYMLINK) != 0) { 315 const char *p; 316 ms->flags &= MAGIC_SYMLINK; 317 p = magic_file(ms, buf); 318 ms->flags |= MAGIC_SYMLINK; 319 return p != NULL ? 1 : -1; 320 } else { /* just print what it points to */ 321 if (mime) { 322 if (handle_mime(ms, mime, "x-symlink") == -1) 323 return -1; 324 } else if (file_printf(ms, "symbolic link to `%s'", 325 buf) == -1) 326 return -1; 327 } 328 return 1; 329 #endif 330 #ifdef S_IFSOCK 331 #ifndef __COHERENT__ 332 case S_IFSOCK: 333 if (mime) { 334 if (handle_mime(ms, mime, "x-socket") == -1) 335 return -1; 336 } else if (file_printf(ms, "socket") == -1) 337 return -1; 338 return 1; 339 #endif 340 #endif 341 case S_IFREG: 342 break; 343 default: 344 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 345 return -1; 346 /*NOTREACHED*/ 347 } 348 349 /* 350 * regular file, check next possibility 351 * 352 * If stat() tells us the file has zero length, report here that 353 * the file is empty, so we can skip all the work of opening and 354 * reading the file. 355 * But if the -s option has been given, we skip this optimization, 356 * since on some systems, stat() reports zero size for raw disk 357 * partitions. (If the block special device really has zero length, 358 * the fact that it is empty will be detected and reported correctly 359 * when we read the file.) 360 */ 361 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 362 if (mime) { 363 if (handle_mime(ms, mime, "x-empty") == -1) 364 return -1; 365 } else if (file_printf(ms, "empty") == -1) 366 return -1; 367 return 1; 368 } 369 return 0; 370 } 371