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/*
* locking.c
* locking extras
*
* Copyright (c) 2012 Nikias Bassen. All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef WIN32
#include <windows.h>
#else
#include <errno.h>
#endif
#include "locking.h"
#include "common.h"
int lock_file(const char* filename, lock_info_t* lockinfo)
{
if (!lockinfo) {
return -1;
}
#ifdef WIN32
lockinfo->fp = CreateFile(filename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (lockinfo->fp == INVALID_HANDLE_VALUE) {
debug("ERROR: could not open or create lockfile '%s'\n", filename);
return -1;
}
lockinfo->ldata.Offset = 0;
lockinfo->ldata.OffsetHigh = 0;
if (!LockFileEx(lockinfo->fp, LOCKFILE_EXCLUSIVE_LOCK, 0, 1, 0, &lockinfo->ldata)) {
debug("ERROR: can't lock file, error %d\n", GetLastError());
CloseHandle(lockinfo->fp);
lockinfo->fp = INVALID_HANDLE_VALUE;
return -1;
}
#else
lockinfo->fp = fopen(filename, "a+");
if (!lockinfo->fp) {
debug("ERROR: could not open or create lockfile '%s'\n", filename);
return -1;
}
lockinfo->ldata.l_type = F_WRLCK;
lockinfo->ldata.l_whence = SEEK_SET;
lockinfo->ldata.l_start = 0;
lockinfo->ldata.l_len = 0;
if (fcntl(fileno(lockinfo->fp), F_SETLKW, &lockinfo->ldata) < 0) {
debug("ERROR: can't lock file, error %d\n", errno);
fclose(lockinfo->fp);
lockinfo->fp = NULL;
return -1;
}
#endif
return 0;
}
int unlock_file(lock_info_t* lockinfo)
{
if (!lockinfo) {
return -1;
}
#ifdef WIN32
if (lockinfo->fp == INVALID_HANDLE_VALUE) {
return -1;
}
lockinfo->ldata.Offset = 0;
lockinfo->ldata.OffsetHigh = 0;
if (!UnlockFileEx(lockinfo->fp, 0, 1, 0, &lockinfo->ldata)) {
debug("ERROR: can't unlock file, error %d\n", GetLastError());
CloseHandle(lockinfo->fp);
lockinfo->fp = INVALID_HANDLE_VALUE;
return -1;
}
CloseHandle(lockinfo->fp);
lockinfo->fp = INVALID_HANDLE_VALUE;
#else
if (!lockinfo->fp) {
return -1;
}
lockinfo->ldata.l_type = F_UNLCK;
lockinfo->ldata.l_whence = SEEK_SET;
lockinfo->ldata.l_start = 0;
lockinfo->ldata.l_len = 0;
if (fcntl(fileno(lockinfo->fp), F_SETLK, &lockinfo->ldata) < 0) {
debug("ERROR: can't unlock file, error %d\n", errno);
fclose(lockinfo->fp);
lockinfo->fp = NULL;
return -1;
}
fclose(lockinfo->fp);
lockinfo->fp = NULL;
#endif
return 0;
}
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