fsmagic.c revision 191736
168349Sobrien/* 2133359Sobrien * Copyright (c) Ian F. Darwin 1986-1995. 3133359Sobrien * Software written by Ian F. Darwin and others; 4133359Sobrien * maintained 1995-present by Christos Zoulas and others. 5133359Sobrien * 6133359Sobrien * Redistribution and use in source and binary forms, with or without 7133359Sobrien * modification, are permitted provided that the following conditions 8133359Sobrien * are met: 9133359Sobrien * 1. Redistributions of source code must retain the above copyright 10133359Sobrien * notice immediately at the beginning of the file, without modification, 11133359Sobrien * this list of conditions, and the following disclaimer. 12133359Sobrien * 2. Redistributions in binary form must reproduce the above copyright 13133359Sobrien * notice, this list of conditions and the following disclaimer in the 14133359Sobrien * documentation and/or other materials provided with the distribution. 15133359Sobrien * 16133359Sobrien * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17133359Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18133359Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19133359Sobrien * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 20133359Sobrien * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21133359Sobrien * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22133359Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23133359Sobrien * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24133359Sobrien * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25133359Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26133359Sobrien * SUCH DAMAGE. 27133359Sobrien */ 28133359Sobrien/* 2968349Sobrien * fsmagic - magic based on filesystem info - directory, special files, etc. 3068349Sobrien */ 3168349Sobrien 3268349Sobrien#include "file.h" 33191736Sobrien 34191736Sobrien#ifndef lint 35191736SobrienFILE_RCSID("@(#)$File: fsmagic.c,v 1.59 2009/02/03 20:27:51 christos Exp $") 36191736Sobrien#endif /* lint */ 37191736Sobrien 38133359Sobrien#include "magic.h" 3968349Sobrien#include <string.h> 4068349Sobrien#ifdef HAVE_UNISTD_H 4168349Sobrien#include <unistd.h> 4268349Sobrien#endif 4368349Sobrien#include <stdlib.h> 44133359Sobrien/* Since major is a function on SVR4, we cannot use `ifndef major'. */ 4568349Sobrien#ifdef MAJOR_IN_MKDEV 4668349Sobrien# include <sys/mkdev.h> 4768349Sobrien# define HAVE_MAJOR 4868349Sobrien#endif 4968349Sobrien#ifdef MAJOR_IN_SYSMACROS 5068349Sobrien# include <sys/sysmacros.h> 5168349Sobrien# define HAVE_MAJOR 5268349Sobrien#endif 5368349Sobrien#ifdef major /* Might be defined in sys/types.h. */ 5468349Sobrien# define HAVE_MAJOR 5568349Sobrien#endif 5668349Sobrien 5768349Sobrien#ifndef HAVE_MAJOR 5868349Sobrien# define major(dev) (((dev) >> 8) & 0xff) 5968349Sobrien# define minor(dev) ((dev) & 0xff) 6068349Sobrien#endif 6168349Sobrien#undef HAVE_MAJOR 6268349Sobrien 63186690Sobrienprivate int 64186690Sobrienbad_link(struct magic_set *ms, int err, char *buf) 65186690Sobrien{ 66186690Sobrien const char *errfmt; 67186690Sobrien int mime = ms->flags & MAGIC_MIME; 68186690Sobrien if ((mime & MAGIC_MIME_TYPE) && 69186690Sobrien file_printf(ms, "application/x-symlink") 70186690Sobrien == -1) 71186690Sobrien return -1; 72186690Sobrien else if (!mime) { 73186690Sobrien if (err == ELOOP) 74186690Sobrien errfmt = "symbolic link in a loop"; 75186690Sobrien else 76186690Sobrien errfmt = "broken symbolic link to `%s'"; 77186690Sobrien if (ms->flags & MAGIC_ERROR) { 78186690Sobrien file_error(ms, err, errfmt, buf); 79186690Sobrien return -1; 80186690Sobrien } 81186690Sobrien if (file_printf(ms, errfmt, buf) == -1) 82186690Sobrien return -1; 83186690Sobrien } 84186690Sobrien return 1; 85186690Sobrien} 86186690Sobrien 87191736Sobrienprivate int 88191736Sobrienhandle_mime(struct magic_set *ms, int mime, const char *str) 89191736Sobrien{ 90191736Sobrien if ((mime & MAGIC_MIME_TYPE)) { 91191736Sobrien if (file_printf(ms, "application/%s", str) == -1) 92191736Sobrien return -1; 93191736Sobrien if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 94191736Sobrien "; charset=") == -1) 95191736Sobrien return -1; 96191736Sobrien } 97191736Sobrien if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 98191736Sobrien return -1; 99191736Sobrien return 0; 100191736Sobrien} 101191736Sobrien 102133359Sobrienprotected int 103133359Sobrienfile_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 10468349Sobrien{ 10568349Sobrien int ret = 0; 106175296Sobrien int mime = ms->flags & MAGIC_MIME; 107133359Sobrien#ifdef S_IFLNK 108133359Sobrien char buf[BUFSIZ+4]; 109133359Sobrien int nch; 110133359Sobrien struct stat tstatbuf; 111133359Sobrien#endif 11268349Sobrien 113191736Sobrien if (ms->flags & MAGIC_APPLE) 114191736Sobrien return 0; 115133359Sobrien if (fn == NULL) 116133359Sobrien return 0; 117133359Sobrien 11868349Sobrien /* 11968349Sobrien * Fstat is cheaper but fails for files you don't have read perms on. 12068349Sobrien * On 4.2BSD and similar systems, use lstat() to identify symlinks. 12168349Sobrien */ 12268349Sobrien#ifdef S_IFLNK 123133359Sobrien if ((ms->flags & MAGIC_SYMLINK) == 0) 12468349Sobrien ret = lstat(fn, sb); 12568349Sobrien else 12668349Sobrien#endif 12768349Sobrien ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 12868349Sobrien 12968349Sobrien if (ret) { 130133359Sobrien if (ms->flags & MAGIC_ERROR) { 131133359Sobrien file_error(ms, errno, "cannot stat `%s'", fn); 132133359Sobrien return -1; 133133359Sobrien } 134139368Sobrien if (file_printf(ms, "cannot open `%s' (%s)", 135133359Sobrien fn, strerror(errno)) == -1) 136133359Sobrien return -1; 13768349Sobrien return 1; 13868349Sobrien } 13968349Sobrien 140186690Sobrien if (!mime) { 14168349Sobrien#ifdef S_ISUID 142133359Sobrien if (sb->st_mode & S_ISUID) 143133359Sobrien if (file_printf(ms, "setuid ") == -1) 144133359Sobrien return -1; 14568349Sobrien#endif 14668349Sobrien#ifdef S_ISGID 147133359Sobrien if (sb->st_mode & S_ISGID) 148133359Sobrien if (file_printf(ms, "setgid ") == -1) 149133359Sobrien return -1; 15068349Sobrien#endif 15168349Sobrien#ifdef S_ISVTX 152133359Sobrien if (sb->st_mode & S_ISVTX) 153133359Sobrien if (file_printf(ms, "sticky ") == -1) 154133359Sobrien return -1; 15568349Sobrien#endif 15668349Sobrien } 15768349Sobrien 15868349Sobrien switch (sb->st_mode & S_IFMT) { 15968349Sobrien case S_IFDIR: 160191736Sobrien if (mime) { 161191736Sobrien if (handle_mime(ms, mime, "x-directory") == -1) 162191736Sobrien return -1; 163191736Sobrien } else if (file_printf(ms, "directory") == -1) 164133359Sobrien return -1; 16568349Sobrien return 1; 16668349Sobrien#ifdef S_IFCHR 16768349Sobrien case S_IFCHR: 16868349Sobrien /* 16968349Sobrien * If -s has been specified, treat character special files 17068349Sobrien * like ordinary files. Otherwise, just report that they 17168349Sobrien * are block special files and go on to the next file. 17268349Sobrien */ 173133359Sobrien if ((ms->flags & MAGIC_DEVICES) != 0) 17468349Sobrien break; 175191736Sobrien if (mime) { 176191736Sobrien if (handle_mime(ms, mime, "x-character-device") == -1) 177191736Sobrien return -1; 178191736Sobrien } else { 179186690Sobrien#ifdef HAVE_STAT_ST_RDEV 18068349Sobrien# ifdef dv_unit 181186690Sobrien if (file_printf(ms, "character special (%d/%d/%d)", 182191736Sobrien major(sb->st_rdev), dv_unit(sb->st_rdev), 183186690Sobrien dv_subunit(sb->st_rdev)) == -1) 184186690Sobrien return -1; 18568349Sobrien# else 186186690Sobrien if (file_printf(ms, "character special (%ld/%ld)", 187191736Sobrien (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) 188191736Sobrien == -1) 189186690Sobrien return -1; 19068349Sobrien# endif 19168349Sobrien#else 192186690Sobrien if (file_printf(ms, "character special") == -1) 193186690Sobrien return -1; 19468349Sobrien#endif 195186690Sobrien } 19668349Sobrien return 1; 19768349Sobrien#endif 19868349Sobrien#ifdef S_IFBLK 19968349Sobrien case S_IFBLK: 20068349Sobrien /* 20168349Sobrien * If -s has been specified, treat block special files 20268349Sobrien * like ordinary files. Otherwise, just report that they 20368349Sobrien * are block special files and go on to the next file. 20468349Sobrien */ 205133359Sobrien if ((ms->flags & MAGIC_DEVICES) != 0) 20668349Sobrien break; 207191736Sobrien if (mime) { 208191736Sobrien if (handle_mime(ms, mime, "x-block-device") == -1) 209191736Sobrien return -1; 210191736Sobrien } else { 211186690Sobrien#ifdef HAVE_STAT_ST_RDEV 21268349Sobrien# ifdef dv_unit 213186690Sobrien if (file_printf(ms, "block special (%d/%d/%d)", 214186690Sobrien major(sb->st_rdev), dv_unit(sb->st_rdev), 215186690Sobrien dv_subunit(sb->st_rdev)) == -1) 216186690Sobrien return -1; 21768349Sobrien# else 218186690Sobrien if (file_printf(ms, "block special (%ld/%ld)", 219186690Sobrien (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1) 220186690Sobrien return -1; 22168349Sobrien# endif 22268349Sobrien#else 223186690Sobrien if (file_printf(ms, "block special") == -1) 224186690Sobrien return -1; 22568349Sobrien#endif 226186690Sobrien } 22768349Sobrien return 1; 22868349Sobrien#endif 22968349Sobrien /* TODO add code to handle V7 MUX and Blit MUX files */ 23068349Sobrien#ifdef S_IFIFO 23168349Sobrien case S_IFIFO: 232159764Sobrien if((ms->flags & MAGIC_DEVICES) != 0) 233159764Sobrien break; 234191736Sobrien if (mime) { 235191736Sobrien if (handle_mime(ms, mime, "x-fifo") == -1) 236191736Sobrien return -1; 237191736Sobrien } else if (file_printf(ms, "fifo (named pipe)") == -1) 238133359Sobrien return -1; 23968349Sobrien return 1; 24068349Sobrien#endif 24168349Sobrien#ifdef S_IFDOOR 24268349Sobrien case S_IFDOOR: 243191736Sobrien if (mime) { 244191736Sobrien if (handle_mime(ms, mime, "x-door") == -1) 245191736Sobrien return -1; 246191736Sobrien } else if (file_printf(ms, "door") == -1) 247133359Sobrien return -1; 24868349Sobrien return 1; 24968349Sobrien#endif 25068349Sobrien#ifdef S_IFLNK 25168349Sobrien case S_IFLNK: 252133359Sobrien if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 253133359Sobrien if (ms->flags & MAGIC_ERROR) { 254133359Sobrien file_error(ms, errno, "unreadable symlink `%s'", 255133359Sobrien fn); 256133359Sobrien return -1; 25768349Sobrien } 258191736Sobrien if (mime) { 259191736Sobrien if (handle_mime(ms, mime, "x-symlink") == -1) 260191736Sobrien return -1; 261191736Sobrien } else if (file_printf(ms, 262133359Sobrien "unreadable symlink `%s' (%s)", fn, 263133359Sobrien strerror(errno)) == -1) 264133359Sobrien return -1; 265133359Sobrien return 1; 266133359Sobrien } 267186690Sobrien buf[nch] = '\0'; /* readlink(2) does not do this */ 26868349Sobrien 269133359Sobrien /* If broken symlink, say so and quit early. */ 270133359Sobrien if (*buf == '/') { 271186690Sobrien if (stat(buf, &tstatbuf) < 0) 272186690Sobrien return bad_link(ms, errno, buf); 273186690Sobrien } else { 274133359Sobrien char *tmp; 275133359Sobrien char buf2[BUFSIZ+BUFSIZ+4]; 27668349Sobrien 277133359Sobrien if ((tmp = strrchr(fn, '/')) == NULL) { 27868349Sobrien tmp = buf; /* in current directory anyway */ 279133359Sobrien } else { 280133359Sobrien if (tmp - fn + 1 > BUFSIZ) { 281133359Sobrien if (ms->flags & MAGIC_ERROR) { 282133359Sobrien file_error(ms, 0, 283133359Sobrien "path too long: `%s'", buf); 284133359Sobrien return -1; 285133359Sobrien } 286191736Sobrien if (mime) { 287191736Sobrien if (handle_mime(ms, mime, 288191736Sobrien "x-path-too-long") == -1) 289191736Sobrien return -1; 290191736Sobrien } else if (file_printf(ms, 291133359Sobrien "path too long: `%s'", fn) == -1) 292133359Sobrien return -1; 293133359Sobrien return 1; 294133359Sobrien } 295191736Sobrien /* take dir part */ 296191736Sobrien (void)strlcpy(buf2, fn, sizeof buf2); 297133359Sobrien buf2[tmp - fn + 1] = '\0'; 298191736Sobrien /* plus (rel) link */ 299191736Sobrien (void)strlcat(buf2, buf, sizeof buf2); 30068349Sobrien tmp = buf2; 301133359Sobrien } 302186690Sobrien if (stat(tmp, &tstatbuf) < 0) 303186690Sobrien return bad_link(ms, errno, buf); 30468349Sobrien } 305133359Sobrien 306133359Sobrien /* Otherwise, handle it. */ 307133359Sobrien if ((ms->flags & MAGIC_SYMLINK) != 0) { 308133359Sobrien const char *p; 309133359Sobrien ms->flags &= MAGIC_SYMLINK; 310133359Sobrien p = magic_file(ms, buf); 311133359Sobrien ms->flags |= MAGIC_SYMLINK; 312133359Sobrien return p != NULL ? 1 : -1; 313133359Sobrien } else { /* just print what it points to */ 314191736Sobrien if (mime) { 315191736Sobrien if (handle_mime(ms, mime, "x-symlink") == -1) 316191736Sobrien return -1; 317191736Sobrien } else if (file_printf(ms, "symbolic link to `%s'", 318133359Sobrien buf) == -1) 319133359Sobrien return -1; 320133359Sobrien } 321186690Sobrien return 1; 32268349Sobrien#endif 32368349Sobrien#ifdef S_IFSOCK 32468349Sobrien#ifndef __COHERENT__ 32568349Sobrien case S_IFSOCK: 326191736Sobrien if (mime) { 327191736Sobrien if (handle_mime(ms, mime, "x-socket") == -1) 328191736Sobrien return -1; 329191736Sobrien } else if (file_printf(ms, "socket") == -1) 330133359Sobrien return -1; 33168349Sobrien return 1; 33268349Sobrien#endif 33368349Sobrien#endif 33468349Sobrien case S_IFREG: 33568349Sobrien break; 33668349Sobrien default: 337133359Sobrien file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 338133359Sobrien return -1; 33968349Sobrien /*NOTREACHED*/ 34068349Sobrien } 34168349Sobrien 34268349Sobrien /* 34368349Sobrien * regular file, check next possibility 34468349Sobrien * 34568349Sobrien * If stat() tells us the file has zero length, report here that 34668349Sobrien * the file is empty, so we can skip all the work of opening and 34768349Sobrien * reading the file. 34868349Sobrien * But if the -s option has been given, we skip this optimization, 34968349Sobrien * since on some systems, stat() reports zero size for raw disk 35068349Sobrien * partitions. (If the block special device really has zero length, 35168349Sobrien * the fact that it is empty will be detected and reported correctly 35268349Sobrien * when we read the file.) 35368349Sobrien */ 354133359Sobrien if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 355191736Sobrien if (mime) { 356191736Sobrien if (handle_mime(ms, mime, "x-empty") == -1) 357191736Sobrien return -1; 358191736Sobrien } else if (file_printf(ms, "empty") == -1) 359133359Sobrien return -1; 36068349Sobrien return 1; 36168349Sobrien } 36268349Sobrien return 0; 36368349Sobrien} 364