1 /* $NetBSD: fsmagic.c,v 1.5 2011/09/16 21:06:26 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 1.64 2011/08/14 09:03:12 christos Exp $") 39 #else 40 __RCSID("$NetBSD: fsmagic.c,v 1.5 2011/09/16 21:06:26 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 int mime = ms->flags & MAGIC_MIME; 73 if ((mime & MAGIC_MIME_TYPE) && 74 file_printf(ms, "inode/symlink") 75 == -1) 76 return -1; 77 else if (!mime) { 78 if (ms->flags & MAGIC_ERROR) { 79 file_error(ms, err, 80 "broken symbolic link to `%s'", buf); 81 return -1; 82 } 83 if (file_printf(ms, "broken symbolic link to `%s'", buf) == -1) 84 return -1; 85 } 86 return 1; 87 } 88 #endif 89 private int 90 handle_mime(struct magic_set *ms, int mime, const char *str) 91 { 92 if ((mime & MAGIC_MIME_TYPE)) { 93 if (file_printf(ms, "inode/%s", str) == -1) 94 return -1; 95 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 96 "; charset=") == -1) 97 return -1; 98 } 99 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 100 return -1; 101 return 0; 102 } 103 104 protected int 105 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 106 { 107 int ret = 0; 108 int mime = ms->flags & MAGIC_MIME; 109 #ifdef S_IFLNK 110 char buf[BUFSIZ+4]; 111 ssize_t nch; 112 struct stat tstatbuf; 113 #endif 114 115 if (ms->flags & MAGIC_APPLE) 116 return 0; 117 if (fn == NULL) 118 return 0; 119 120 /* 121 * Fstat is cheaper but fails for files you don't have read perms on. 122 * On 4.2BSD and similar systems, use lstat() to identify symlinks. 123 */ 124 #ifdef S_IFLNK 125 if ((ms->flags & MAGIC_SYMLINK) == 0) 126 ret = lstat(fn, sb); 127 else 128 #endif 129 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 130 131 if (ret) { 132 if (ms->flags & MAGIC_ERROR) { 133 file_error(ms, errno, "cannot stat `%s'", fn); 134 return -1; 135 } 136 if (file_printf(ms, "cannot open `%s' (%s)", 137 fn, strerror(errno)) == -1) 138 return -1; 139 ms->event_flags |= EVENT_HAD_ERR; 140 return -1; 141 } 142 143 if (!mime) { 144 #ifdef S_ISUID 145 if (sb->st_mode & S_ISUID) 146 if (file_printf(ms, "setuid ") == -1) 147 return -1; 148 #endif 149 #ifdef S_ISGID 150 if (sb->st_mode & S_ISGID) 151 if (file_printf(ms, "setgid ") == -1) 152 return -1; 153 #endif 154 #ifdef S_ISVTX 155 if (sb->st_mode & S_ISVTX) 156 if (file_printf(ms, "sticky ") == -1) 157 return -1; 158 #endif 159 } 160 161 switch (sb->st_mode & S_IFMT) { 162 case S_IFDIR: 163 if (mime) { 164 if (handle_mime(ms, mime, "directory") == -1) 165 return -1; 166 } else if (file_printf(ms, "directory") == -1) 167 return -1; 168 return 1; 169 #ifdef S_IFCHR 170 case S_IFCHR: 171 /* 172 * If -s has been specified, treat character special files 173 * like ordinary files. Otherwise, just report that they 174 * are block special files and go on to the next file. 175 */ 176 if ((ms->flags & MAGIC_DEVICES) != 0) 177 break; 178 if (mime) { 179 if (handle_mime(ms, mime, "chardevice") == -1) 180 return -1; 181 } else { 182 #ifdef HAVE_STAT_ST_RDEV 183 # ifdef dv_unit 184 if (file_printf(ms, "character special (%d/%d/%d)", 185 major(sb->st_rdev), dv_unit(sb->st_rdev), 186 dv_subunit(sb->st_rdev)) == -1) 187 return -1; 188 # else 189 if (file_printf(ms, "character special (%ld/%ld)", 190 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 191 == -1) 192 return -1; 193 # endif 194 #else 195 if (file_printf(ms, "character special") == -1) 196 return -1; 197 #endif 198 } 199 return 1; 200 #endif 201 #ifdef S_IFBLK 202 case S_IFBLK: 203 /* 204 * If -s has been specified, treat block special files 205 * like ordinary files. Otherwise, just report that they 206 * are block special files and go on to the next file. 207 */ 208 if ((ms->flags & MAGIC_DEVICES) != 0) 209 break; 210 if (mime) { 211 if (handle_mime(ms, mime, "blockdevice") == -1) 212 return -1; 213 } else { 214 #ifdef HAVE_STAT_ST_RDEV 215 # ifdef dv_unit 216 if (file_printf(ms, "block special (%d/%d/%d)", 217 major(sb->st_rdev), dv_unit(sb->st_rdev), 218 dv_subunit(sb->st_rdev)) == -1) 219 return -1; 220 # else 221 if (file_printf(ms, "block special (%ld/%ld)", 222 (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 223 return -1; 224 # endif 225 #else 226 if (file_printf(ms, "block special") == -1) 227 return -1; 228 #endif 229 } 230 return 1; 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, "fifo (named pipe)") == -1) 241 return -1; 242 return 1; 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, "door") == -1) 250 return -1; 251 return 1; 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 "unreadable symlink `%s' (%s)", fn, 266 strerror(errno)) == -1) 267 return -1; 268 return 1; 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 "path too long: `%s'", fn) == -1) 295 return -1; 296 return 1; 297 } 298 /* take dir part */ 299 (void)strlcpy(buf2, fn, sizeof buf2); 300 buf2[tmp - fn + 1] = '\0'; 301 /* plus (rel) link */ 302 (void)strlcat(buf2, buf, sizeof buf2); 303 tmp = buf2; 304 } 305 if (stat(tmp, &tstatbuf) < 0) 306 return bad_link(ms, errno, buf); 307 } 308 309 /* Otherwise, handle it. */ 310 if ((ms->flags & MAGIC_SYMLINK) != 0) { 311 const char *p; 312 ms->flags &= MAGIC_SYMLINK; 313 p = magic_file(ms, buf); 314 ms->flags |= MAGIC_SYMLINK; 315 return p != NULL ? 1 : -1; 316 } else { /* just print what it points to */ 317 if (mime) { 318 if (handle_mime(ms, mime, "symlink") == -1) 319 return -1; 320 } else if (file_printf(ms, "symbolic link to `%s'", 321 buf) == -1) 322 return -1; 323 } 324 return 1; 325 #endif 326 #ifdef S_IFSOCK 327 #ifndef __COHERENT__ 328 case S_IFSOCK: 329 if (mime) { 330 if (handle_mime(ms, mime, "socket") == -1) 331 return -1; 332 } else if (file_printf(ms, "socket") == -1) 333 return -1; 334 return 1; 335 #endif 336 #endif 337 case S_IFREG: 338 break; 339 default: 340 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 341 return -1; 342 /*NOTREACHED*/ 343 } 344 345 /* 346 * regular file, check next possibility 347 * 348 * If stat() tells us the file has zero length, report here that 349 * the file is empty, so we can skip all the work of opening and 350 * reading the file. 351 * But if the -s option has been given, we skip this optimization, 352 * since on some systems, stat() reports zero size for raw disk 353 * partitions. (If the block special device really has zero length, 354 * the fact that it is empty will be detected and reported correctly 355 * when we read the file.) 356 */ 357 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 358 if (mime) { 359 if (handle_mime(ms, mime, "x-empty") == -1) 360 return -1; 361 } else if (file_printf(ms, "empty") == -1) 362 return -1; 363 return 1; 364 } 365 return 0; 366 } 367