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/** @file
* @brief Helper functions for database handling
*/
/* Copyright 2002-2020 Olly Betts
* Copyright 2008 Lemur Consulting Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see
* <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "databasehelpers.h"
#include "backends.h"
#include "glass/glass_defs.h"
#include "honey/honey_defs.h"
#include "io_utils.h"
#include "omassert.h"
#include "posixy_wrapper.h"
#include <algorithm>
#include <cstring>
#include <string>
#include <sys/types.h>
#include "safesysstat.h"
#include "safeunistd.h"
using namespace std;
static int
test_if_single_file_db_(int fd, off_t pos)
{
#if defined XAPIAN_HAS_GLASS_BACKEND || \
defined XAPIAN_HAS_HONEY_BACKEND
char magic_buf[14];
// FIXME: Don't duplicate magic check here...
if (io_read(fd, magic_buf, 14) == 14 &&
lseek(fd, pos, SEEK_SET) == pos &&
memcmp(magic_buf, "\x0f\x0dXapian ", 9) == 0) {
switch (magic_buf[9]) {
#ifdef XAPIAN_HAS_GLASS_BACKEND
case 'G':
if (memcmp(magic_buf + 10, "lass", 4) == 0) {
return BACKEND_GLASS;
}
break;
#endif
#ifdef XAPIAN_HAS_HONEY_BACKEND
case 'H':
if (memcmp(magic_buf + 10, "oney", 4) == 0) {
return BACKEND_HONEY;
}
break;
#endif
}
return BACKEND_UNKNOWN;
}
#else
(void)fd;
#endif
return BACKEND_UNKNOWN;
}
int
test_if_single_file_db(int fd)
{
off_t pos = lseek(fd, 0, SEEK_CUR);
if (pos < 0) {
return BACKEND_UNKNOWN;
}
return test_if_single_file_db_(fd, pos);
}
int
test_if_single_file_db(const struct stat& sb,
const string& path,
int* fd_ptr)
{
Assert(fd_ptr);
#if defined XAPIAN_HAS_GLASS_BACKEND || \
defined XAPIAN_HAS_HONEY_BACKEND
if (!S_ISREG(sb.st_mode)) return BACKEND_UNKNOWN;
// Look at the size as a clue - if it's less than both GLASS_MIN_BLOCKSIZE
// and HONEY_MIN_DB_SIZE then it's not a single-file glass or honey
// database. For a larger file, we peek at the start of the file to
// determine what it is.
if (sb.st_size < min(GLASS_MIN_BLOCKSIZE, HONEY_MIN_DB_SIZE))
return BACKEND_UNKNOWN;
int fd = posixy_open(path.c_str(), O_RDONLY|O_BINARY);
if (fd != -1) {
int result = test_if_single_file_db_(fd, off_t{0});
if (result != BACKEND_UNKNOWN) {
*fd_ptr = fd;
} else {
::close(fd);
}
return result;
}
#else
(void)sb;
(void)path;
(void)fd_ptr;
#endif
return BACKEND_UNKNOWN;
}
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