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/* $OpenBSD: fsmagic.c,v 1.14 2009/10/27 23:59:37 deraadt Exp $ */
/*
* Copyright (c) Ian F. Darwin 1986-1995.
* Software written by Ian F. Darwin and others;
* maintained 1995-present by Christos Zoulas and others.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, without modification,
* this list of conditions, and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* fsmagic - magic based on filesystem info - directory, special files, etc.
*/
#include "file.h"
#include "magic.h"
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <sys/stat.h>
/* Since major is a function on SVR4, we cannot use `ifndef major'. */
#ifdef MAJOR_IN_MKDEV
# include <sys/mkdev.h>
# define HAVE_MAJOR
#endif
#ifdef MAJOR_IN_SYSMACROS
# include <sys/sysmacros.h>
# define HAVE_MAJOR
#endif
#ifdef major /* Might be defined in sys/types.h. */
# define HAVE_MAJOR
#endif
#ifndef HAVE_MAJOR
# define major(dev) (((dev) >> 8) & 0xff)
# define minor(dev) ((dev) & 0xff)
#endif
#undef HAVE_MAJOR
private int
bad_link(struct magic_set *ms, int err, char *buf)
{
char *errfmt;
if (err == ELOOP)
errfmt = "symbolic link in a loop";
else
errfmt = "broken symbolic link to `%s'";
if (ms->flags & MAGIC_ERROR) {
file_error(ms, err, errfmt, buf);
return -1;
}
if (file_printf(ms, errfmt, buf) == -1)
return -1;
return 1;
}
protected int
file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
{
int ret = 0;
int mime = ms->flags & MAGIC_MIME;
#ifdef S_IFLNK
char buf[BUFSIZ+4];
int nch;
struct stat tstatbuf;
#endif
if (fn == NULL)
return 0;
/*
* Fstat is cheaper but fails for files you don't have read perms on.
* On 4.2BSD and similar systems, use lstat() to identify symlinks.
*/
#ifdef S_IFLNK
if ((ms->flags & MAGIC_SYMLINK) == 0)
ret = lstat(fn, sb);
else
#endif
ret = stat(fn, sb); /* don't merge into if; see "ret =" above */
if (ret) {
if (ms->flags & MAGIC_ERROR) {
file_error(ms, errno, "cannot stat `%s'", fn);
return -1;
}
if (file_printf(ms, "cannot open `%s' (%s)",
fn, strerror(errno)) == -1)
return -1;
return 1;
}
if (mime) {
if ((sb->st_mode & S_IFMT) != S_IFREG) {
if ((mime & MAGIC_MIME_TYPE) &&
file_printf(ms, "application/x-not-regular-file")
== -1)
return -1;
return 1;
}
}
else {
#ifdef S_ISUID
if (sb->st_mode & S_ISUID)
if (file_printf(ms, "setuid ") == -1)
return -1;
#endif
#ifdef S_ISGID
if (sb->st_mode & S_ISGID)
if (file_printf(ms, "setgid ") == -1)
return -1;
#endif
#ifdef S_ISVTX
if (sb->st_mode & S_ISVTX)
if (file_printf(ms, "sticky ") == -1)
return -1;
#endif
}
switch (sb->st_mode & S_IFMT) {
case S_IFDIR:
if (file_printf(ms, "directory") == -1)
return -1;
return 1;
#ifdef S_IFCHR
case S_IFCHR:
/*
* If -s has been specified, treat character special files
* like ordinary files. Otherwise, just report that they
* are block special files and go on to the next file.
*/
if ((ms->flags & MAGIC_DEVICES) != 0)
break;
#ifdef HAVE_STAT_ST_RDEV
# ifdef dv_unit
if (file_printf(ms, "character special (%d/%d/%d)",
major(sb->st_rdev), dv_unit(sb->st_rdev),
dv_subunit(sb->st_rdev)) == -1)
return -1;
# else
if (file_printf(ms, "character special (%ld/%ld)",
(long) major(sb->st_rdev), (long) minor(sb->st_rdev)) == -1)
return -1;
# endif
#else
if (file_printf(ms, "character special") == -1)
return -1;
#endif
return 1;
#endif
#ifdef S_IFBLK
case S_IFBLK:
/*
* If -s has been specified, treat block special files
* like ordinary files. Otherwise, just report that they
* are block special files and go on to the next file.
*/
if ((ms->flags & MAGIC_DEVICES) != 0)
break;
#ifdef HAVE_STAT_ST_RDEV
# ifdef dv_unit
if (file_printf(ms, "block special (%d/%d/%d)",
major(sb->st_rdev), dv_unit(sb->st_rdev),
dv_subunit(sb->st_rdev)) == -1)
return -1;
# else
if (file_printf(ms, "block special (%ld/%ld)",
(long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1)
return -1;
# endif
#else
if (file_printf(ms, "block special") == -1)
return -1;
#endif
return 1;
#endif
/* TODO add code to handle V7 MUX and Blit MUX files */
#ifdef S_IFIFO
case S_IFIFO:
if((ms->flags & MAGIC_DEVICES) != 0)
break;
if (file_printf(ms, "fifo (named pipe)") == -1)
return -1;
return 1;
#endif
#ifdef S_IFDOOR
case S_IFDOOR:
if (file_printf(ms, "door") == -1)
return -1;
return 1;
#endif
#ifdef S_IFLNK
case S_IFLNK:
if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
if (ms->flags & MAGIC_ERROR) {
file_error(ms, errno, "unreadable symlink `%s'",
fn);
return -1;
}
if (file_printf(ms,
"unreadable symlink `%s' (%s)", fn,
strerror(errno)) == -1)
return -1;
return 1;
}
buf[nch] = '\0'; /* readlink(2) does not do this */
/* If broken symlink, say so and quit early. */
if (*buf == '/') {
if (stat(buf, &tstatbuf) < 0)
return bad_link(ms, errno, buf);
} else {
char *tmp;
char buf2[BUFSIZ+BUFSIZ+4];
if ((tmp = strrchr(fn, '/')) == NULL) {
tmp = buf; /* in current directory anyway */
} else {
if (tmp - fn + 1 > BUFSIZ) {
if (ms->flags & MAGIC_ERROR) {
file_error(ms, 0,
"path too long: `%s'", buf);
return -1;
}
if (file_printf(ms,
"path too long: `%s'", fn) == -1)
return -1;
return 1;
}
(void)strlcpy(buf2, fn, sizeof buf2); /* take dir part */
buf2[tmp - fn + 1] = '\0';
(void)strlcat(buf2, buf, sizeof buf2); /* plus (rel) link */
tmp = buf2;
}
if (stat(tmp, &tstatbuf) < 0)
return bad_link(ms, errno, buf);
}
/* Otherwise, handle it. */
if ((ms->flags & MAGIC_SYMLINK) != 0) {
const char *p;
ms->flags &= MAGIC_SYMLINK;
p = magic_file(ms, buf);
ms->flags |= MAGIC_SYMLINK;
return p != NULL ? 1 : -1;
} else { /* just print what it points to */
if (file_printf(ms, "symbolic link to `%s'",
buf) == -1)
return -1;
}
return 1;
#endif
#ifdef S_IFSOCK
#ifndef __COHERENT__
case S_IFSOCK:
if (file_printf(ms, "socket") == -1)
return -1;
return 1;
#endif
#endif
case S_IFREG:
break;
default:
file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
return -1;
/*NOTREACHED*/
}
/*
* regular file, check next possibility
*
* If stat() tells us the file has zero length, report here that
* the file is empty, so we can skip all the work of opening and
* reading the file.
* But if the -s option has been given, we skip this optimization,
* since on some systems, stat() reports zero size for raw disk
* partitions. (If the block special device really has zero length,
* the fact that it is empty will be detected and reported correctly
* when we read the file.)
*/
if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
file_printf(ms, mime ? "application/x-empty" :
"empty") == -1)
return -1;
return 1;
}
return 0;
}
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