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/*
* Copyright (c) Christos Zoulas 2003.
* All Rights Reserved.
*
* 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.
*/

#ifdef _MSC_VER
#include <windows.h>
#include <shlwapi.h>
#endif

#include "file.h"

#ifndef lint
FILE_RCSID("@(#)$File: magic.c,v 1.77 2012/10/31 17:20:06 christos Exp $")
#endif /* lint */

#include "magic.h"

#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#ifdef QUICK
#include <sys/mman.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h> /* for PIPE_BUF */
#endif

#if defined(HAVE_UTIMES)
# include <sys/time.h>
#elif defined(HAVE_UTIME)
# if defined(HAVE_SYS_UTIME_H)
# include <sys/utime.h>
# elif defined(HAVE_UTIME_H)
# include <utime.h>
# endif
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h> /* for read() */
#endif

#ifndef PIPE_BUF
/* Get the PIPE_BUF from pathconf */
#ifdef _PC_PIPE_BUF
#define PIPE_BUF pathconf(".", _PC_PIPE_BUF)
#else
#define PIPE_BUF 512
#endif
#endif

private void close_and_restore(const struct magic_set *, const char *, int,
    const struct stat *);
private int unreadable_info(struct magic_set *, mode_t, const char *);
private const char* get_default_magic(void);
#ifndef COMPILE_ONLY
private const char *file_or_fd(struct magic_set *, const char *, int);
#endif

#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif

private const char *
get_default_magic(void)
{
static const char hmagic[] = "/.magic/magic.mgc";
static char *default_magic;
char *home, *hmagicpath;

#ifndef WIN32
struct stat st;

if (default_magic) {
free(default_magic);
default_magic = NULL;
}
if ((home = getenv("HOME")) == NULL)
return MAGIC;

if (asprintf(&hmagicpath, "%s/.magic.mgc", home) < 0)
return MAGIC;
if (stat(hmagicpath, &st) == -1) {
free(hmagicpath);
if (asprintf(&hmagicpath, "%s/.magic", home) < 0)
return MAGIC;
if (stat(hmagicpath, &st) == -1)
goto out;
if (S_ISDIR(st.st_mode)) {
free(hmagicpath);
if (asprintf(&hmagicpath, "%s/%s", home, hmagic) < 0)
return MAGIC;
if (access(hmagicpath, R_OK) == -1)
goto out;
}
}

if (asprintf(&default_magic, "%s:%s", hmagicpath, MAGIC) < 0)
goto out;
free(hmagicpath);
return default_magic;
out:
default_magic = NULL;
free(hmagicpath);
return MAGIC;
#else
char *hmagicp = hmagicpath;
char *tmppath = NULL;

#define APPENDPATH() \
do { \
if (tmppath && access(tmppath, R_OK) != -1) { \
if (hmagicpath == NULL) \
hmagicpath = tmppath; \
else { \
if (asprintf(&hmagicp, "%s%c%s", hmagicpath, \
PATHSEP, tmppath) >= 0) { \
free(hmagicpath); \
hmagicpath = hmagicp; \
} \
free(tmppath); \
} \
tmppath = NULL; \
} \
} while (/*CONSTCOND*/0)

if (default_magic) {
free(default_magic);
default_magic = NULL;
}

/* First, try to get user-specific magic file */
if ((home = getenv("LOCALAPPDATA")) == NULL) {
if ((home = getenv("USERPROFILE")) != NULL)
if (asprintf(&tmppath,
"%s/Local Settings/Application Data%s", home,
hmagic) < 0)
tmppath = NULL;
} else {
if (asprintf(&tmppath, "%s%s", home, hmagic) < 0)
tmppath = NULL;
}

APPENDPATH();

/* Second, try to get a magic file from Common Files */
if ((home = getenv("COMMONPROGRAMFILES")) != NULL) {
if (asprintf(&tmppath, "%s%s", home, hmagic) >= 0)
APPENDPATH();
}

/* Third, try to get magic file relative to dll location */
/*LPTSTR dllpath = malloc(sizeof(*dllpath) * (MAX_PATH + 1));
dllpath[MAX_PATH] = 0; // just in case long path gets truncated and not null terminated
if (GetModuleFileNameA(NULL, dllpath, MAX_PATH)){
PathRemoveFileSpecA(dllpath);
if (strlen(dllpath) > 3 &&
stricmp(&dllpath[strlen(dllpath) - 3], "bin") == 0) {
if (asprintf(&tmppath,
"%s/../share/misc/magic.mgc", dllpath) >= 0)
APPENDPATH();
} else {
if (asprintf(&tmppath,
"%s/share/misc/magic.mgc", dllpath) >= 0)
APPENDPATH();
else if (asprintf(&tmppath,
"%s/magic.mgc", dllpath) >= 0)
APPENDPATH();
}
}*/

/* Don't put MAGIC constant - it likely points to a file within MSys
tree */
default_magic = hmagicpath;
return default_magic;
#endif
}

public const char *
magic_getpath(const char *magicfile, int action)
{
if (magicfile != NULL)
return magicfile;

magicfile = getenv("MAGIC");
if (magicfile != NULL)
return magicfile;

return action == FILE_LOAD ? get_default_magic() : MAGIC;
}

public struct magic_set *
magic_open(int flags)
{
return file_ms_alloc(flags);
}

private int
unreadable_info(struct magic_set *ms, mode_t md, const char *file)
{
/* We cannot open it, but we were able to stat it. */
if (access(file, W_OK) == 0)
if (file_printf(ms, "writable, ") == -1)
return -1;
if (access(file, X_OK) == 0)
if (file_printf(ms, "executable, ") == -1)
return -1;
if (S_ISREG(md))
if (file_printf(ms, "regular file, ") == -1)
return -1;
if (file_printf(ms, "no read permission") == -1)
return -1;
return 0;
}

public void
magic_close(struct magic_set *ms)
{
if (ms == NULL)
return;
file_ms_free(ms);
}

/*
* load a magic file
*/
public int
magic_load(struct magic_set *ms, const char *magicfile)
{
if (ms == NULL)
return -1;
return file_apprentice(ms, magicfile, FILE_LOAD);
}

public int
magic_compile(struct magic_set *ms, const char *magicfile)
{
if (ms == NULL)
return -1;
return file_apprentice(ms, magicfile, FILE_COMPILE);
}

public int
magic_check(struct magic_set *ms, const char *magicfile)
{
if (ms == NULL)
return -1;
return file_apprentice(ms, magicfile, FILE_CHECK);
}

public int
magic_list(struct magic_set *ms, const char *magicfile)
{
if (ms == NULL)
return -1;
return file_apprentice(ms, magicfile, FILE_LIST);
}

private void
close_and_restore(const struct magic_set *ms, const char *name, int fd,
    const struct stat *sb)
{
if (fd == STDIN_FILENO)
return;
(void) close(fd);

if ((ms->flags & MAGIC_PRESERVE_ATIME) != 0) {
/*
* Try to restore access, modification times if read it.
* This is really *bad* because it will modify the status
* time of the file... And of course this will affect
* backup programs
*/
#ifdef HAVE_UTIMES
struct timeval utsbuf[2];
(void)memset(utsbuf, 0, sizeof(utsbuf));
utsbuf[0].tv_sec = sb->st_atime;
utsbuf[1].tv_sec = sb->st_mtime;

(void) utimes(name, utsbuf); /* don't care if loses */
#elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H)
struct utimbuf utbuf;

(void)memset(&utbuf, 0, sizeof(utbuf));
utbuf.actime = sb->st_atime;
utbuf.modtime = sb->st_mtime;
(void) utime(name, &utbuf); /* don't care if loses */
#endif
}
}

#ifndef COMPILE_ONLY

/*
* find type of descriptor
*/
public const char *
magic_descriptor(struct magic_set *ms, int fd)
{
if (ms == NULL)
return NULL;
return file_or_fd(ms, NULL, fd);
}

/*
* find type of named file
*/
public const char *
magic_file(struct magic_set *ms, const char *inname)
{
if (ms == NULL)
return NULL;
return file_or_fd(ms, inname, STDIN_FILENO);
}

private const char *
file_or_fd(struct magic_set *ms, const char *inname, int fd)
{
int rv = -1;
unsigned char *buf;
struct stat sb;
ssize_t nbytes = 0; /* number of bytes read from a datafile */
int ispipe = 0;

/*
* one extra for terminating '\0', and
* some overlapping space for matches near EOF
*/
#define SLOP (1 + sizeof(union VALUETYPE))
if ((buf = CAST(unsigned char *, malloc(HOWMANY + SLOP))) == NULL)
return NULL;

if (file_reset(ms) == -1)
goto done;

switch (file_fsmagic(ms, inname, &sb)) {
case -1: /* error */
goto done;
case 0: /* nothing found */
break;
default: /* matched it and printed type */
rv = 0;
goto done;
}

if (inname == NULL) {
if (fstat(fd, &sb) == 0 && S_ISFIFO(sb.st_mode))
ispipe = 1;
} else {
int flags = O_RDONLY|O_BINARY;

if (stat(inname, &sb) == 0 && S_ISFIFO(sb.st_mode)) {
#ifdef O_NONBLOCK
flags |= O_NONBLOCK;
#endif
ispipe = 1;
}

errno = 0;
if ((fd = open(inname, flags)) < 0) {
if (unreadable_info(ms, sb.st_mode, inname) == -1)
goto done;
rv = 0;
goto done;
}
#ifdef O_NONBLOCK
if ((flags = fcntl(fd, F_GETFL)) != -1) {
flags &= ~O_NONBLOCK;
(void)fcntl(fd, F_SETFL, flags);
}
#endif
}

/*
* try looking at the first HOWMANY bytes
*/
if (ispipe) {
ssize_t r = 0;

while ((r = sread(fd, (void *)&buf[nbytes],
(size_t)(HOWMANY - nbytes), 1)) > 0) {
nbytes += r;
if (r < PIPE_BUF) break;
}

if (nbytes == 0) {
/* We can not read it, but we were able to stat it. */
if (unreadable_info(ms, sb.st_mode, inname) == -1)
goto done;
rv = 0;
goto done;
}

} else {
if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) {
file_error(ms, errno, "cannot read `%s'", inname);
goto done;
}
}

(void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */
if (file_buffer(ms, fd, inname, buf, (size_t)nbytes) == -1)
goto done;
rv = 0;
done:
free(buf);
close_and_restore(ms, inname, fd, &sb);
return rv == 0 ? file_getbuffer(ms) : NULL;
}


public const char *
magic_buffer(struct magic_set *ms, const void *buf, size_t nb)
{
if (ms == NULL)
return NULL;
if (file_reset(ms) == -1)
return NULL;
/*
* The main work is done here!
* We have the file name and/or the data buffer to be identified.
*/
if (file_buffer(ms, -1, NULL, buf, nb) == -1) {
return NULL;
}
return file_getbuffer(ms);
}
#endif

public const char *
magic_error(struct magic_set *ms)
{
if (ms == NULL)
return "Magic database is not open";
return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL;
}

public int
magic_errno(struct magic_set *ms)
{
if (ms == NULL)
return EINVAL;
return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0;
}

public int
magic_setflags(struct magic_set *ms, int flags)
{
if (ms == NULL)
return -1;
#if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES)
if (flags & MAGIC_PRESERVE_ATIME)
return -1;
#endif
ms->flags = flags;
return 0;
}

public int
magic_version(void)
{
return MAGIC_VERSION;
}
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