修正全局变量初始化时序问题导致的内存访问异常

Author: mutouyun

include/libipc/ipc.h

@@ -19,6 +19,8 @@ enum : unsigned {
 
 template <typename Flag>
 struct IPC_EXPORT chan_impl {
+    static ipc::handle_t inited();
+
     static bool connect   (ipc::handle_t * ph, char const * name, unsigned mode);
     static bool reconnect (ipc::handle_t * ph, unsigned mode);
     static void disconnect(ipc::handle_t h);
@@ -41,7 +43,7 @@ class chan_wrapper {
 private:
     using detail_t = chan_impl<Flag>;
 
-    ipc::handle_t h_ = nullptr;
+    ipc::handle_t h_ = detail_t::inited();
     unsigned mode_   = ipc::sender;
     bool connected_  = false;
 

src/libipc/ipc.cpp

@@ -630,6 +630,12 @@ using policy_t = ipc::policy::choose<ipc::circ::elem_array, Flag>;
 
 namespace ipc {
 
+template <typename Flag>
+ipc::handle_t chan_impl<Flag>::inited() {
+    ipc::detail::waiter::init();
+    return nullptr;
+}
+
 template <typename Flag>
 bool chan_impl<Flag>::connect(ipc::handle_t * ph, char const * name, unsigned mode) {
     return detail_impl<policy_t<Flag>>::connect(ph, name, mode & receiver);

src/libipc/platform/linux/mutex.h

@@ -125,8 +125,8 @@ class mutex {
         IPC_UNUSED_ std::lock_guard<std::mutex> guard {info.lock};
         auto it = info.mutex_handles.find(name);
         if (it == info.mutex_handles.end()) {
-            it = curr_prog::get().mutex_handles.emplace(name, 
-                              curr_prog::shm_data::init{name}).first;
+            it = info.mutex_handles.emplace(name, 
+                  curr_prog::shm_data::init{name}).first;
         }
         mutex_ = &it->second.mtx;
         ref_   = &it->second.ref;
@@ -135,20 +135,26 @@ class mutex {
     template <typename F>
     void release_mutex(ipc::string const &name, F &&clear) {
         if (name.empty()) return;
-        IPC_UNUSED_ std::lock_guard<std::mutex> guard {curr_prog::get().lock};
-        auto it = curr_prog::get().mutex_handles.find(name);
-        if (it == curr_prog::get().mutex_handles.end()) {
+        auto &info = curr_prog::get();
+        IPC_UNUSED_ std::lock_guard<std::mutex> guard {info.lock};
+        auto it = info.mutex_handles.find(name);
+        if (it == info.mutex_handles.end()) {
             return;
         }
         if (clear()) {
-            curr_prog::get().mutex_handles.erase(it);
+            info.mutex_handles.erase(it);
         }
     }
 
 public:
     mutex() = default;
     ~mutex() = default;
 
+    static void init() {
+        // Avoid exception problems caused by static member initialization order.
+        curr_prog::get();
+    }
+
     a0_mtx_t const *native() const noexcept {
         return valid() ? mutex_->native() : nullptr;
     }

src/libipc/platform/posix/mutex.h

@@ -55,8 +55,8 @@ class mutex {
         IPC_UNUSED_ std::lock_guard<std::mutex> guard {info.lock};
         auto it = info.mutex_handles.find(name);
         if (it == info.mutex_handles.end()) {
-            it = curr_prog::get().mutex_handles.emplace(name, 
-                              curr_prog::shm_data::init{name, sizeof(pthread_mutex_t)}).first;
+            it = info.mutex_handles.emplace(name, 
+                  curr_prog::shm_data::init{name, sizeof(pthread_mutex_t)}).first;
         }
         shm_ = &it->second.shm;
         ref_ = &it->second.ref;
@@ -69,20 +69,26 @@ class mutex {
     template <typename F>
     void release_mutex(ipc::string const &name, F &&clear) {
         if (name.empty()) return;
-        IPC_UNUSED_ std::lock_guard<std::mutex> guard {curr_prog::get().lock};
-        auto it = curr_prog::get().mutex_handles.find(name);
-        if (it == curr_prog::get().mutex_handles.end()) {
+        auto &info = curr_prog::get();
+        IPC_UNUSED_ std::lock_guard<std::mutex> guard {info.lock};
+        auto it = info.mutex_handles.find(name);
+        if (it == info.mutex_handles.end()) {
             return;
         }
         if (clear()) {
-            curr_prog::get().mutex_handles.erase(it);
+            info.mutex_handles.erase(it);
         }
     }
 
 public:
     mutex() = default;
     ~mutex() = default;
 
+    static void init() {
+        // Avoid exception problems caused by static member initialization order.
+        curr_prog::get();
+    }
+
     pthread_mutex_t const *native() const noexcept {
         return mutex_;
     }

src/libipc/platform/win/mutex.h

@@ -21,6 +21,8 @@ class mutex {
     mutex() noexcept = default;
     ~mutex() noexcept = default;
 
+    static void init() {}
+
     HANDLE native() const noexcept {
         return h_;
     }

src/libipc/sync/waiter.cpp

@@ -0,0 +1,22 @@
+#include "libipc/waiter.h"
+
+#include "libipc/platform/detail.h"
+#if defined(IPC_OS_WINDOWS_)
+#include "libipc/platform/win/mutex.h"
+#elif defined(IPC_OS_LINUX_)
+#include "libipc/platform/linux/mutex.h"
+#elif defined(IPC_OS_QNX_)
+#include "libipc/platform/posix/mutex.h"
+#else/*IPC_OS*/
+#   error "Unsupported platform."
+#endif
+
+namespace ipc {
+namespace detail {
+
+void waiter::init() {
+    ipc::detail::sync::mutex::init();
+}
+
+} // namespace detail
+} // namespace ipc

src/libipc/waiter.h

@@ -19,6 +19,8 @@ class waiter {
     std::atomic<bool>    quit_ {false};
 
 public:
+    static void init();
+
     waiter() = default;
     waiter(char const *name) {
         open(name);