231 lines
6.5 KiB
C
231 lines
6.5 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* File: w32ipcsem.c
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* Description: implements named semaphores for NT and WIN95.
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*/
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#include "primpl.h"
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#ifdef WINCE
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static HANDLE OpenSemaphore(DWORD inDesiredAccess,
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BOOL inInheritHandle,
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const char *inName)
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{
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HANDLE retval = NULL;
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HANDLE semaphore = NULL;
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PRUnichar wideName[MAX_PATH]; /* name size is limited to MAX_PATH */
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MultiByteToWideChar(CP_ACP, 0, inName, -1, wideName, MAX_PATH);
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/* 0x7fffffff is the max count for our semaphore */
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semaphore = CreateSemaphoreW(NULL, 0, 0x7fffffff, wideName);
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if (NULL != semaphore) {
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DWORD lastErr = GetLastError();
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if (ERROR_ALREADY_EXISTS != lastErr) {
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CloseHandle(semaphore);
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}
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else {
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retval = semaphore;
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}
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}
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return retval;
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}
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#endif
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/*
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* NSPR-to-NT access right mapping table for semaphore objects.
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*
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* The SYNCHRONIZE access is required by WaitForSingleObject.
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* The SEMAPHORE_MODIFY_STATE access is required by ReleaseSemaphore.
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* The OR of these three access masks must equal SEMAPHORE_ALL_ACCESS.
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* This is because if a semaphore object with the specified name
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* exists, CreateSemaphore requests SEMAPHORE_ALL_ACCESS access to
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* the existing object.
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*/
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static DWORD semAccessTable[] = {
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STANDARD_RIGHTS_REQUIRED|0x1, /* read (0x1 is "query state") */
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STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|SEMAPHORE_MODIFY_STATE, /* write */
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0 /* execute */
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};
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#ifndef _PR_GLOBAL_THREADS_ONLY
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/*
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* A fiber cannot call WaitForSingleObject because that
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* will block the other fibers running on the same thread.
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* If a fiber needs to wait on a (semaphore) handle, we
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* create a native thread to call WaitForSingleObject and
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* have the fiber join the native thread.
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*/
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/*
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* Arguments, return value, and error code for WaitForSingleObject
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*/
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struct WaitSingleArg {
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HANDLE handle;
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DWORD timeout;
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DWORD rv;
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DWORD error;
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};
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static void WaitSingleThread(void *arg)
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{
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struct WaitSingleArg *warg = (struct WaitSingleArg *) arg;
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warg->rv = WaitForSingleObject(warg->handle, warg->timeout);
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if (warg->rv == WAIT_FAILED) {
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warg->error = GetLastError();
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}
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}
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static DWORD FiberSafeWaitForSingleObject(
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HANDLE hHandle,
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DWORD dwMilliseconds
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)
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{
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PRThread *me = _PR_MD_CURRENT_THREAD();
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if (_PR_IS_NATIVE_THREAD(me)) {
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return WaitForSingleObject(hHandle, dwMilliseconds);
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} else {
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PRThread *waitThread;
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struct WaitSingleArg warg;
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PRStatus rv;
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warg.handle = hHandle;
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warg.timeout = dwMilliseconds;
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waitThread = PR_CreateThread(
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PR_USER_THREAD, WaitSingleThread, &warg,
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PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD, PR_JOINABLE_THREAD, 0);
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if (waitThread == NULL) {
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return WAIT_FAILED;
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}
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rv = PR_JoinThread(waitThread);
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PR_ASSERT(rv == PR_SUCCESS);
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if (rv == PR_FAILURE) {
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return WAIT_FAILED;
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}
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if (warg.rv == WAIT_FAILED) {
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SetLastError(warg.error);
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}
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return warg.rv;
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}
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}
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#endif /* !_PR_GLOBAL_THREADS_ONLY */
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PRSem *_PR_MD_OPEN_SEMAPHORE(
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const char *osname, PRIntn flags, PRIntn mode, PRUintn value)
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{
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PRSem *sem;
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SECURITY_ATTRIBUTES sa;
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LPSECURITY_ATTRIBUTES lpSA = NULL;
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PSECURITY_DESCRIPTOR pSD = NULL;
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PACL pACL = NULL;
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sem = PR_NEW(PRSem);
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if (sem == NULL) {
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PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
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return NULL;
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}
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if (flags & PR_SEM_CREATE) {
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if (_PR_NT_MakeSecurityDescriptorACL(mode, semAccessTable,
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&pSD, &pACL) == PR_SUCCESS) {
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sa.nLength = sizeof(sa);
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sa.lpSecurityDescriptor = pSD;
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sa.bInheritHandle = FALSE;
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lpSA = &sa;
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}
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#ifdef WINCE
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{
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/* The size of a sem's name is limited to MAX_PATH. */
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PRUnichar wosname[MAX_PATH];
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MultiByteToWideChar(CP_ACP, 0, osname, -1, wosname, MAX_PATH);
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sem->sem = CreateSemaphoreW(lpSA, value, 0x7fffffff, wosname);
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}
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#else
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sem->sem = CreateSemaphoreA(lpSA, value, 0x7fffffff, osname);
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#endif
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if (lpSA != NULL) {
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_PR_NT_FreeSecurityDescriptorACL(pSD, pACL);
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}
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if (sem->sem == NULL) {
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_PR_MD_MAP_DEFAULT_ERROR(GetLastError());
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PR_DELETE(sem);
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return NULL;
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}
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if ((flags & PR_SEM_EXCL) && (GetLastError() == ERROR_ALREADY_EXISTS)) {
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PR_SetError(PR_FILE_EXISTS_ERROR, ERROR_ALREADY_EXISTS);
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CloseHandle(sem->sem);
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PR_DELETE(sem);
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return NULL;
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}
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} else {
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sem->sem = OpenSemaphore(
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SEMAPHORE_MODIFY_STATE|SYNCHRONIZE, FALSE, osname);
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if (sem->sem == NULL) {
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DWORD err = GetLastError();
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/*
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* If we open a nonexistent named semaphore, NT
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* returns ERROR_FILE_NOT_FOUND, while Win95
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* returns ERROR_INVALID_NAME
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*/
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if (err == ERROR_INVALID_NAME) {
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PR_SetError(PR_FILE_NOT_FOUND_ERROR, err);
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} else {
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_PR_MD_MAP_DEFAULT_ERROR(GetLastError());
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}
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PR_DELETE(sem);
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return NULL;
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}
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}
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return sem;
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}
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PRStatus _PR_MD_WAIT_SEMAPHORE(PRSem *sem)
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{
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DWORD rv;
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#ifdef _PR_GLOBAL_THREADS_ONLY
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rv = WaitForSingleObject(sem->sem, INFINITE);
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#else
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rv = FiberSafeWaitForSingleObject(sem->sem, INFINITE);
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#endif
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PR_ASSERT(rv == WAIT_FAILED || rv == WAIT_OBJECT_0);
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if (rv == WAIT_FAILED) {
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_PR_MD_MAP_DEFAULT_ERROR(GetLastError());
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return PR_FAILURE;
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}
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if (rv != WAIT_OBJECT_0) {
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/* Should not happen */
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PR_SetError(PR_UNKNOWN_ERROR, 0);
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return PR_FAILURE;
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}
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return PR_SUCCESS;
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}
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PRStatus _PR_MD_POST_SEMAPHORE(PRSem *sem)
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{
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if (ReleaseSemaphore(sem->sem, 1, NULL) == FALSE) {
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_PR_MD_MAP_DEFAULT_ERROR(GetLastError());
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return PR_FAILURE;
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}
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return PR_SUCCESS;
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}
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PRStatus _PR_MD_CLOSE_SEMAPHORE(PRSem *sem)
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{
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if (CloseHandle(sem->sem) == FALSE) {
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_PR_MD_MAP_CLOSE_ERROR(GetLastError());
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return PR_FAILURE;
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}
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PR_DELETE(sem);
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return PR_SUCCESS;
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}
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