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ea8dc7e0f2
*- file is now broken into a library containing and processing the magic and a consumer binary.
344 lines
8.0 KiB
C
344 lines
8.0 KiB
C
/*
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* Copyright (c) Christos Zoulas 2003.
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* All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice immediately at the beginning of the file, without modification,
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* this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "file.h"
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#include "magic.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/param.h> /* for MAXPATHLEN */
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#include <sys/stat.h>
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#include <fcntl.h> /* for open() */
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#ifdef QUICK
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#include <sys/mman.h>
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#endif
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#if defined(HAVE_UTIMES)
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# include <sys/time.h>
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#elif defined(HAVE_UTIME)
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# if defined(HAVE_SYS_UTIME_H)
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# include <sys/utime.h>
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# elif defined(HAVE_UTIME_H)
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# include <utime.h>
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# endif
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h> /* for read() */
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#endif
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#ifdef HAVE_LOCALE_H
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#include <locale.h>
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#endif
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#include <netinet/in.h> /* for byte swapping */
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#include "patchlevel.h"
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#ifndef lint
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FILE_RCSID("@(#)$Id: magic.c,v 1.22 2004/07/24 19:55:17 christos Exp $")
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#endif /* lint */
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#ifdef __EMX__
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private char *apptypeName = NULL;
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protected int file_os2_apptype(struct magic_set *ms, const char *fn,
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const void *buf, size_t nb);
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#endif /* __EMX__ */
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private void free_mlist(struct mlist *);
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private void close_and_restore(const struct magic_set *, const char *, int,
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const struct stat *);
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public struct magic_set *
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magic_open(int flags)
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{
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struct magic_set *ms;
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if ((ms = malloc(sizeof(struct magic_set))) == NULL)
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return NULL;
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if (magic_setflags(ms, flags) == -1) {
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free(ms);
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errno = EINVAL;
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return NULL;
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}
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ms->o.ptr = ms->o.buf = malloc(ms->o.size = 1024);
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ms->o.len = 0;
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if (ms->o.buf == NULL) {
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free(ms);
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return NULL;
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}
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ms->o.pbuf = malloc(ms->o.psize = 1024);
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if (ms->o.pbuf == NULL) {
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free(ms->o.buf);
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free(ms);
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return NULL;
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}
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ms->c.off = malloc((ms->c.len = 10) * sizeof(*ms->c.off));
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if (ms->c.off == NULL) {
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free(ms->o.pbuf);
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free(ms->o.buf);
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free(ms);
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return NULL;
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}
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ms->haderr = 0;
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ms->error = -1;
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ms->mlist = NULL;
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return ms;
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}
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private void
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free_mlist(struct mlist *mlist)
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{
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struct mlist *ml;
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if (mlist == NULL)
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return;
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for (ml = mlist->next; ml != mlist;) {
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struct mlist *next = ml->next;
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struct magic *mg = ml->magic;
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file_delmagic(mg, ml->mapped, ml->nmagic);
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free(ml);
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ml = next;
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}
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free(ml);
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}
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public void
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magic_close(ms)
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struct magic_set *ms;
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{
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free_mlist(ms->mlist);
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free(ms->o.buf);
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free(ms->c.off);
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free(ms);
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}
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/*
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* load a magic file
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*/
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public int
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magic_load(struct magic_set *ms, const char *magicfile)
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{
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struct mlist *ml = file_apprentice(ms, magicfile, FILE_LOAD);
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if (ml) {
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free_mlist(ms->mlist);
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ms->mlist = ml;
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return 0;
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}
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return -1;
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}
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public int
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magic_compile(struct magic_set *ms, const char *magicfile)
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{
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struct mlist *ml = file_apprentice(ms, magicfile, FILE_COMPILE);
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free_mlist(ml);
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return ml ? 0 : -1;
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}
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public int
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magic_check(struct magic_set *ms, const char *magicfile)
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{
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struct mlist *ml = file_apprentice(ms, magicfile, FILE_CHECK);
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free_mlist(ml);
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return ml ? 0 : -1;
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}
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private void
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close_and_restore(const struct magic_set *ms, const char *name, int fd,
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const struct stat *sb)
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{
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(void) close(fd);
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if (fd != STDIN_FILENO && (ms->flags & MAGIC_PRESERVE_ATIME) != 0) {
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/*
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* Try to restore access, modification times if read it.
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* This is really *bad* because it will modify the status
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* time of the file... And of course this will affect
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* backup programs
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*/
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#ifdef HAVE_UTIMES
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struct timeval utsbuf[2];
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utsbuf[0].tv_sec = sb->st_atime;
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utsbuf[1].tv_sec = sb->st_mtime;
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(void) utimes(name, utsbuf); /* don't care if loses */
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#elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H)
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struct utimbuf utbuf;
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utbuf.actime = sb->st_atime;
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utbuf.modtime = sb->st_mtime;
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(void) utime(name, &utbuf); /* don't care if loses */
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#endif
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}
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}
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#ifndef COMPILE_ONLY
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/*
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* find type of named file
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*/
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public const char *
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magic_file(struct magic_set *ms, const char *inname)
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{
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int fd = 0;
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unsigned char buf[HOWMANY+1]; /* one extra for terminating '\0' */
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struct stat sb;
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ssize_t nbytes = 0; /* number of bytes read from a datafile */
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if (file_reset(ms) == -1)
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return NULL;
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switch (file_fsmagic(ms, inname, &sb)) {
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case -1:
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return NULL;
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case 0:
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break;
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default:
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return file_getbuffer(ms);
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}
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#ifndef STDIN_FILENO
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#define STDIN_FILENO 0
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#endif
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if (inname == NULL)
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fd = STDIN_FILENO;
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else if ((fd = open(inname, O_RDONLY)) < 0) {
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/* We cannot open it, but we were able to stat it. */
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if (sb.st_mode & 0222)
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if (file_printf(ms, "writable, ") == -1)
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return NULL;
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if (sb.st_mode & 0111)
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if (file_printf(ms, "executable, ") == -1)
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return NULL;
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if (S_ISREG(sb.st_mode))
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if (file_printf(ms, "regular file, ") == -1)
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return NULL;
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if (file_printf(ms, "no read permission") == -1)
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return NULL;
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return file_getbuffer(ms);
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}
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/*
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* try looking at the first HOWMANY bytes
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*/
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if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) {
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file_error(ms, errno, "cannot read `%s'", inname);
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goto done;
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}
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if (nbytes == 0) {
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if (file_printf(ms, (ms->flags & MAGIC_MIME) ?
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"application/x-empty" : "empty") == -1)
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goto done;
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goto gotit;
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} else if (nbytes == 1) {
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if (file_printf(ms, "very short file (no magic)") == -1)
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goto done;
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goto gotit;
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} else {
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buf[nbytes] = '\0'; /* null-terminate it */
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#ifdef __EMX__
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switch (file_os2_apptype(ms, inname, buf, nbytes)) {
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case -1:
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goto done;
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case 0:
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break;
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default:
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goto gotit;
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}
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#endif
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if (file_buffer(ms, buf, (size_t)nbytes) == -1)
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goto done;
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#ifdef BUILTIN_ELF
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if (nbytes > 5) {
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/*
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* We matched something in the file, so this *might*
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* be an ELF file, and the file is at least 5 bytes
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* long, so if it's an ELF file it has at least one
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* byte past the ELF magic number - try extracting
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* information from the ELF headers that cannot easily
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* be extracted with rules in the magic file.
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*/
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file_tryelf(ms, fd, buf, (size_t)nbytes);
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}
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#endif
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}
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gotit:
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close_and_restore(ms, inname, fd, &sb);
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return file_getbuffer(ms);
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done:
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close_and_restore(ms, inname, fd, &sb);
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return NULL;
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}
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public const char *
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magic_buffer(struct magic_set *ms, const void *buf, size_t nb)
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{
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if (file_reset(ms) == -1)
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return NULL;
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/*
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* The main work is done here!
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* We have the file name and/or the data buffer to be identified.
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*/
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if (file_buffer(ms, buf, nb) == -1) {
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return NULL;
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}
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return file_getbuffer(ms);
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}
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#endif
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public const char *
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magic_error(struct magic_set *ms)
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{
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return ms->haderr ? ms->o.buf : NULL;
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}
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public int
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magic_errno(struct magic_set *ms)
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{
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return ms->haderr ? ms->error : 0;
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}
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public int
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magic_setflags(struct magic_set *ms, int flags)
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{
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#if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES)
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if (flags & MAGIC_PRESERVE_ATIME)
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return -1;
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#endif
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ms->flags = flags;
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return 0;
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}
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