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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)db_os_fid.c 10.7 (Sleepycat) 8/21/97";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "os_ext.h"
#include "common_ext.h"
/*
* __db_fileid --
* Return a unique identifier for a file.
*
* PUBLIC: int __db_fileid __P((DB_ENV *, const char *, int, u_int8_t *));
*/
int
__db_fileid(dbenv, fname, timestamp, fidp)
DB_ENV *dbenv;
const char *fname;
int timestamp;
u_int8_t *fidp;
{
time_t now;
u_int8_t *p;
unsigned int i;
#ifdef _WIN32
/*
* The documentation for GetFileInformationByHandle() states that the
* inode-type numbers are not constant between processes. Actually,
* they are, they're the NTFS MFT indexes. So, this works on NTFS,
* but perhaps not on other platforms, and perhaps not over a network.
* Can't think of a better solution right now.
*/
int fd = 0;
HANDLE fh = 0;
BY_HANDLE_FILE_INFORMATION fi;
BOOL retval = FALSE;
/* Clear the buffer. */
memset(fidp, 0, DB_FILE_ID_LEN);
/* first we open the file, because we're not given a handle to it */
fd = open(fname,_O_RDONLY,_S_IREAD);
if (-1 == fd) {
/* If we can't open it, we're in trouble */
return (errno);
}
/* File open, get its info */
fh = (HANDLE)_get_osfhandle(fd);
if ((HANDLE)(-1) != fh) {
retval = GetFileInformationByHandle(fh,&fi);
}
close(fd);
/*
* We want the three 32-bit words which tell us the volume ID and
* the file ID. We make a crude attempt to copy the bytes over to
* the callers buffer.
*
* DBDB: really we should ensure that the bytes get packed the same
* way on all compilers, platforms etc.
*/
if ( ((HANDLE)(-1) != fh) && (TRUE == retval) ) {
memcpy(fidp, &fi.nFileIndexLow, sizeof(u_int32_t));
fidp += sizeof(u_int32_t);
memcpy(fidp, &fi.nFileIndexHigh, sizeof(u_int32_t));
fidp += sizeof(u_int32_t);
memcpy(fidp, &fi.dwVolumeSerialNumber, sizeof(u_int32_t));
}
#else
struct stat sb;
/* Clear the buffer. */
memset(fidp, 0, DB_FILE_ID_LEN);
/* Check for the unthinkable. */
if (sizeof(sb.st_ino) +
sizeof(sb.st_dev) + sizeof(time_t) > DB_FILE_ID_LEN)
return (EINVAL);
/* On UNIX, use a dev/inode pair. */
if (stat(fname, &sb)) {
__db_err(dbenv, "%s: %s", fname, strerror(errno));
return (errno);
}
/*
* Use the inode first and in reverse order, hopefully putting the
* distinguishing information early in the string.
*/
for (p = (u_int8_t *)&sb.st_ino +
sizeof(sb.st_ino), i = 0; i < sizeof(sb.st_ino); ++i)
*fidp++ = *--p;
for (p = (u_int8_t *)&sb.st_dev +
sizeof(sb.st_dev), i = 0; i < sizeof(sb.st_dev); ++i)
*fidp++ = *--p;
#endif
if (timestamp) {
(void)time(&now);
for (p = (u_int8_t *)&now +
sizeof(now), i = 0; i < sizeof(now); ++i)
*fidp++ = *--p;
}
return (0);
}
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