用Visual锁定SAL
用Visual锁定SAL
提问于 2022-02-08 00:48:35
我正在尝试添加锁定SAL语句，以在我的应用程序中查找/防止不正确的锁定。比如缺少锁定呼叫和不匹配的锁定呼叫。我收到了我不明白的警告。我把它们作为注释放在下面的例子中。我打开了代码分析并设置了Microsoft的所有规则。我正在使用Visual 2019 16.11.9。我还试用了Visual 2022 17.0.5并获得了相同的结果。
我已经用_Success_代替_When_了。我尝试返回bool，而不是BOOL和_Success_(返回)和_Success_(返回!= 0)。
我读过的一些研究：
https://learn.microsoft.com/en-us/cpp/code-quality/c26135?view=msvc-170
_When_(return != 0, _Acquires_lock_(p->cs))
int TryEnter(DATA* p)
{
if (p->state != 0)
{
EnterCriticalSection(&p->cs);
return p->state;
}
return 0;
}前一篇文章是从2021年开始的，因此可能比后一篇Visual 2015的文章更新得更多。VS2015示例不起作用；似乎_Success_注释已经更改，因为它不再接受两个参数。
// Incorrect
_Success_(return == TRUE, _Acquires_lock_(*lpCriticalSection))
BOOL WINAPI TryEnterCriticalSection(
_Inout_ LPCRITICAL_SECTION lpCriticalSection
);
// Correct
_Success_(return != 0, _Acquires_lock_(*lpCriticalSection))
BOOL WINAPI TryEnterCriticalSection(
_Inout_ LPCRITICAL_SECTION lpCriticalSection
); 我的测试代码：
#define _WIN32_WINNT _WIN32_WINNT_WIN7
#include <windows.h>
#include <tchar.h>
// https://learn.microsoft.com/en-us/cpp/code-quality/c26135?view=msvc-170
class CLock {
public:
CLock() noexcept : m_hMutex(CreateMutex(nullptr,FALSE,nullptr)){
}
~CLock(){
CloseHandle(m_hMutex);
m_hMutex = nullptr;
}
_When_(return != 0, _Acquires_lock_(this->m_hMutex)) BOOL Lock() noexcept {
// warning C26135: Missing annotation _Acquires_lock_(this->m_hMutex) at function 'CLock::Lock'.
// I don't understand this warning, I have the annotation?
return (WaitForSingleObject(m_hMutex,INFINITE) == WAIT_OBJECT_0);
}
_When_(return != 0, _Releases_lock_(this->m_hMutex)) BOOL Unlock() noexcept {
// warning C26135 : Missing annotation _Releases_lock_(this->m_hMutex) at function 'CLock::Unlock'.
// I don't understand this warning, I have the annotation?
return ReleaseMutex(m_hMutex);
}
private:
// Ensure no copies can be made
CLock(const CLock &lCopy) = delete;
CLock(const CLock &&lMove) = delete;
const CLock &operator=(const CLock &lCopy) = delete;
const CLock &&operator=(const CLock &&lMove) = delete;
_Has_lock_kind_(_Lock_kind_mutex_) HANDLE m_hMutex;
};
class ThreadedThingy {
public:
ThreadedThingy() noexcept : m_iThingy(0){
}
VOID TestBadNotLocked() noexcept {
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_
// at function 'ThreadedThingy::TestBadNotLocked'. Otherwise it could be a race
// condition. Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// This should be a warning since the lock isn't held
m_iThingy = 10;
}
VOID TestBadNotUnlocked() noexcept {
if (m_lLock.Lock()){
// warning C26165: Possibly failing to release lock '(&this->m_lLock)->m_hMutex' in function
// 'ThreadedThingy::TestBadNotUnlocked'.
// This should be a warning since lock isn't unlocked
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_
// at function 'ThreadedThingy::TestBadNotUnlocked'. Otherwise it could be a race
// condition. Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// I don't understand this warning, the lock is held
m_iThingy = 20;
}
}
VOID TestGood() noexcept {
if (m_lLock.Lock()){
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_ at
// function 'ThreadedThingy::TestGood'. Otherwise it could be a race condition.
// Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// I don't understand this warning, the lock is held
m_iThingy = 20;
// warning C26165: Possibly failing to release lock '(&this->m_lLock)->m_hMutex' in function
// 'ThreadedThingy::TestGood'.
// I kind of understand this warning because Unlock can't gaurentee the lock is released
m_lLock.Unlock();
}
}
private:
_Has_lock_kind_(_Lock_kind_mutex_) CLock m_lLock;
_Guarded_by_(this->m_lLock) INT m_iThingy;
};
INT _tmain() noexcept {
ThreadedThingy ttTest;
ttTest.TestBadNotLocked();
ttTest.TestBadNotUnlocked();
ttTest.TestGood();
return 0;
}谢谢!
-Daniel
回答 1
Stack Overflow用户
回答已采纳
发布于 2022-03-11 06:39:23
我和微软开了一张罚单，想得到一个答案。我学到了三件事。首先，当WaitForSingleObject返回WAIT_ABANDONED时，它意味着锁现在是拥有的，类似于它返回WAIT_OBJECT_0但没有发出信号的时候。因此，您必须检查这两个返回值，否则它会说您没有正确的注释。其次，静态代码分析工具假设ReleaseMutex总是释放锁。因此，解锁()上的_When_注释是不必要的/错误的。最后，还需要另一个注释将互斥锁链接到CLock对象。这个注释是_Post_same_lock_。Google并没有太多的注释，只是头文件。工作守则：
#define _WIN32_WINNT _WIN32_WINNT_WIN7
#include <windows.h>
#include <tchar.h>
class CLock {
public:
CLock() noexcept : m_hMutex(CreateMutex(nullptr,FALSE,nullptr)){
}
~CLock(){
CloseHandle(m_hMutex);
m_hMutex = nullptr;
}
_When_(return != 0, _Acquires_lock_(this->m_hMutex) _Post_same_lock_(*this, this->m_hMutex)) BOOL Lock() noexcept {
const DWORD dwWait = WaitForSingleObject(m_hMutex, INFINITE);
// You have to do more than this to handle WAIT_ABANDONED_0
// This example is only about SAL, not how to corretly handle WAIT_ABANDONED_0
return ((dwWait == WAIT_OBJECT_0) || (dwWait == WAIT_ABANDONED_0));
}
_Releases_lock_(this->m_hMutex) VOID Unlock() noexcept {
ReleaseMutex(m_hMutex);
}
private:
// Ensure no copies can be made
CLock(const CLock &lCopy) = delete;
CLock(const CLock &&lMove) = delete;
const CLock &operator=(const CLock &lCopy) = delete;
const CLock &&operator=(const CLock &&lMove) = delete;
_Has_lock_kind_(_Lock_kind_mutex_) HANDLE m_hMutex;
};
class ThreadedThingy {
public:
ThreadedThingy() noexcept : m_iThingy(0){
}
VOID TestBadNotLocked() noexcept {
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_
// at function 'ThreadedThingy::TestBadNotLocked'. Otherwise it could be a race
// condition. Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// This should be a warning since the lock isn't held
m_iThingy = 10;
}
VOID TestBadNotUnlocked() noexcept {
if (m_lLock.Lock()){
// warning C26165: Possibly failing to release lock '(&this->m_lLock)->m_hMutex' in function
// 'ThreadedThingy::TestBadNotUnlocked'.
// This should be a warning since lock isn't unlocked
m_iThingy = 20;
}
}
VOID TestGood() noexcept {
if (m_lLock.Lock()){
m_iThingy = 20;
m_lLock.Unlock();
}
}
private:
CLock m_lLock;
_Guarded_by_(this->m_lLock) INT m_iThingy;
};
INT _tmain() noexcept {
ThreadedThingy ttTest;
ttTest.TestBadNotLocked();
ttTest.TestBadNotUnlocked();
ttTest.TestGood();
return 0;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/71027258
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