1 /* $NetBSD: fsmagic.c,v 1.2 2009/05/08 17:28:01 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 1.59 2009/02/03 20:27:51 christos Exp $") 39 #else 40 __RCSID("$NetBSD: fsmagic.c,v 1.2 2009/05/08 17:28:01 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 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 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 return 1; 144 } 145 146 if (!mime) { 147 #ifdef S_ISUID 148 if (sb->st_mode & S_ISUID) 149 if (file_printf(ms, "setuid ") == -1) 150 return -1; 151 #endif 152 #ifdef S_ISGID 153 if (sb->st_mode & S_ISGID) 154 if (file_printf(ms, "setgid ") == -1) 155 return -1; 156 #endif 157 #ifdef S_ISVTX 158 if (sb->st_mode & S_ISVTX) 159 if (file_printf(ms, "sticky ") == -1) 160 return -1; 161 #endif 162 } 163 164 switch (sb->st_mode & S_IFMT) { 165 case S_IFDIR: 166 if (mime) { 167 if (handle_mime(ms, mime, "x-directory") == -1) 168 return -1; 169 } else if (file_printf(ms, "directory") == -1) 170 return -1; 171 return 1; 172 #ifdef S_IFCHR 173 case S_IFCHR: 174 /* 175 * If -s has been specified, treat character special files 176 * like ordinary files. Otherwise, just report that they 177 * are block special files and go on to the next file. 178 */ 179 if ((ms->flags & MAGIC_DEVICES) != 0) 180 break; 181 if (mime) { 182 if (handle_mime(ms, mime, "x-character-device") == -1) 183 return -1; 184 } else { 185 #ifdef HAVE_STAT_ST_RDEV 186 # ifdef dv_unit 187 if (file_printf(ms, "character special (%d/%d/%d)", 188 major(sb->st_rdev), dv_unit(sb->st_rdev), 189 dv_subunit(sb->st_rdev)) == -1) 190 return -1; 191 # else 192 if (file_printf(ms, "character special (%ld/%ld)", 193 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 194 == -1) 195 return -1; 196 # endif 197 #else 198 if (file_printf(ms, "character special") == -1) 199 return -1; 200 #endif 201 } 202 return 1; 203 #endif 204 #ifdef S_IFBLK 205 case S_IFBLK: 206 /* 207 * If -s has been specified, treat block special files 208 * like ordinary files. Otherwise, just report that they 209 * are block special files and go on to the next file. 210 */ 211 if ((ms->flags & MAGIC_DEVICES) != 0) 212 break; 213 if (mime) { 214 if (handle_mime(ms, mime, "x-block-device") == -1) 215 return -1; 216 } else { 217 #ifdef HAVE_STAT_ST_RDEV 218 # ifdef dv_unit 219 if (file_printf(ms, "block special (%d/%d/%d)", 220 major(sb->st_rdev), dv_unit(sb->st_rdev), 221 dv_subunit(sb->st_rdev)) == -1) 222 return -1; 223 # else 224 if (file_printf(ms, "block special (%ld/%ld)", 225 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 226 return -1; 227 # endif 228 #else 229 if (file_printf(ms, "block special") == -1) 230 return -1; 231 #endif 232 } 233 return 1; 234 #endif 235 /* TODO add code to handle V7 MUX and Blit MUX files */ 236 #ifdef S_IFIFO 237 case S_IFIFO: 238 if((ms->flags & MAGIC_DEVICES) != 0) 239 break; 240 if (mime) { 241 if (handle_mime(ms, mime, "x-fifo") == -1) 242 return -1; 243 } else if (file_printf(ms, "fifo (named pipe)") == -1) 244 return -1; 245 return 1; 246 #endif 247 #ifdef S_IFDOOR 248 case S_IFDOOR: 249 if (mime) { 250 if (handle_mime(ms, mime, "x-door") == -1) 251 return -1; 252 } else if (file_printf(ms, "door") == -1) 253 return -1; 254 return 1; 255 #endif 256 #ifdef S_IFLNK 257 case S_IFLNK: 258 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 259 if (ms->flags & MAGIC_ERROR) { 260 file_error(ms, errno, "unreadable symlink `%s'", 261 fn); 262 return -1; 263 } 264 if (mime) { 265 if (handle_mime(ms, mime, "x-symlink") == -1) 266 return -1; 267 } else if (file_printf(ms, 268 "unreadable symlink `%s' (%s)", fn, 269 strerror(errno)) == -1) 270 return -1; 271 return 1; 272 } 273 buf[nch] = '\0'; /* readlink(2) does not do this */ 274 275 /* If broken symlink, say so and quit early. */ 276 if (*buf == '/') { 277 if (stat(buf, &tstatbuf) < 0) 278 return bad_link(ms, errno, buf); 279 } else { 280 char *tmp; 281 char buf2[BUFSIZ+BUFSIZ+4]; 282 283 if ((tmp = strrchr(fn, '/')) == NULL) { 284 tmp = buf; /* in current directory anyway */ 285 } else { 286 if (tmp - fn + 1 > BUFSIZ) { 287 if (ms->flags & MAGIC_ERROR) { 288 file_error(ms, 0, 289 "path too long: `%s'", buf); 290 return -1; 291 } 292 if (mime) { 293 if (handle_mime(ms, mime, 294 "x-path-too-long") == -1) 295 return -1; 296 } else if (file_printf(ms, 297 "path too long: `%s'", fn) == -1) 298 return -1; 299 return 1; 300 } 301 /* take dir part */ 302 (void)strlcpy(buf2, fn, sizeof buf2); 303 buf2[tmp - fn + 1] = '\0'; 304 /* plus (rel) link */ 305 (void)strlcat(buf2, buf, sizeof buf2); 306 tmp = buf2; 307 } 308 if (stat(tmp, &tstatbuf) < 0) 309 return bad_link(ms, errno, buf); 310 } 311 312 /* Otherwise, handle it. */ 313 if ((ms->flags & MAGIC_SYMLINK) != 0) { 314 const char *p; 315 ms->flags &= MAGIC_SYMLINK; 316 p = magic_file(ms, buf); 317 ms->flags |= MAGIC_SYMLINK; 318 return p != NULL ? 1 : -1; 319 } else { /* just print what it points to */ 320 if (mime) { 321 if (handle_mime(ms, mime, "x-symlink") == -1) 322 return -1; 323 } else if (file_printf(ms, "symbolic link to `%s'", 324 buf) == -1) 325 return -1; 326 } 327 return 1; 328 #endif 329 #ifdef S_IFSOCK 330 #ifndef __COHERENT__ 331 case S_IFSOCK: 332 if (mime) { 333 if (handle_mime(ms, mime, "x-socket") == -1) 334 return -1; 335 } else if (file_printf(ms, "socket") == -1) 336 return -1; 337 return 1; 338 #endif 339 #endif 340 case S_IFREG: 341 break; 342 default: 343 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 344 return -1; 345 /*NOTREACHED*/ 346 } 347 348 /* 349 * regular file, check next possibility 350 * 351 * If stat() tells us the file has zero length, report here that 352 * the file is empty, so we can skip all the work of opening and 353 * reading the file. 354 * But if the -s option has been given, we skip this optimization, 355 * since on some systems, stat() reports zero size for raw disk 356 * partitions. (If the block special device really has zero length, 357 * the fact that it is empty will be detected and reported correctly 358 * when we read the file.) 359 */ 360 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 361 if (mime) { 362 if (handle_mime(ms, mime, "x-empty") == -1) 363 return -1; 364 } else if (file_printf(ms, "empty") == -1) 365 return -1; 366 return 1; 367 } 368 return 0; 369 } 370