Fix FreeBSD-specific issues in POSIX implementation

This commit addresses the test failures reported in issue #156
on FreeBSD platform.

1. Fix POSIX semaphore naming for FreeBSD compatibility
   - FreeBSD requires semaphore names to start with "/"
   - Add "_sem" suffix to avoid namespace conflicts with shm
   - Store semaphore name separately for proper cleanup
   - This fixes all 24 semaphore test failures

2. Fix robust mutex EOWNERDEAD handling
   - When pthread_mutex_lock returns EOWNERDEAD, the lock is
     already acquired by the calling thread
   - After calling pthread_mutex_consistent(), we should return
     success immediately, not unlock and retry
   - Previous behavior caused issues with FreeBSD's libthr robust
     mutex list management, leading to fatal errors
   - This fixes the random crashes in MutexTest

Technical details:
- EOWNERDEAD indicates the previous lock owner died while holding
  the lock, but the current thread has successfully acquired it
- pthread_mutex_consistent() restores the mutex to a consistent state
- The Linux implementation worked differently, but the new approach
  is more correct according to POSIX semantics and works on both
  Linux and FreeBSD

Fixes #156

Author: mutouyun

src/libipc/platform/posix/mutex.h

@@ -214,13 +214,13 @@ class mutex {
                         ipc::error("fail pthread_mutex_lock[%d], pthread_mutex_consistent[%d]\n", eno, eno2);
                         return false;
                     }
-                    int eno3 = ::pthread_mutex_unlock(mutex_);
-                    if (eno3 != 0) {
-                        ipc::error("fail pthread_mutex_lock[%d], pthread_mutex_unlock[%d]\n", eno, eno3);
-                        return false;
-                    }
+                    // EOWNERDEAD means we have successfully acquired the lock,
+                    // but the previous owner died. After calling pthread_mutex_consistent(),
+                    // the mutex is now in a consistent state and we hold the lock.
+                    // We should return success here, not unlock and retry.
+                    // This avoids issues with FreeBSD's robust mutex list management.
+                    return true;
                 }
-                break; // loop again
             default:
                 ipc::error("fail pthread_mutex_lock[%d]\n", eno);
                 return false;
@@ -244,15 +244,11 @@ class mutex {
                 int eno2 = ::pthread_mutex_consistent(mutex_);
                 if (eno2 != 0) {
                     ipc::error("fail pthread_mutex_timedlock[%d], pthread_mutex_consistent[%d]\n", eno, eno2);
-                    break;
-                }
-                int eno3 = ::pthread_mutex_unlock(mutex_);
-                if (eno3 != 0) {
-                    ipc::error("fail pthread_mutex_timedlock[%d], pthread_mutex_unlock[%d]\n", eno, eno3);
-                    break;
+                    throw std::system_error{eno2, std::system_category()};
                 }
+                // Successfully acquired the lock after making it consistent
+                return true;
             }
-            break;
         default:
             ipc::error("fail pthread_mutex_timedlock[%d]\n", eno);
             break;

src/libipc/platform/posix/semaphore_impl.h

@@ -19,6 +19,7 @@ namespace sync {
 class semaphore {
     ipc::shm::handle shm_;
     sem_t *h_ = SEM_FAILED;
+    std::string sem_name_;  // Store the actual semaphore name used
 
 public:
     semaphore() = default;
@@ -38,9 +39,16 @@ class semaphore {
             ipc::error("[open_semaphore] fail shm.acquire: %s\n", name);
             return false;
         }
-        h_ = ::sem_open(name, O_CREAT, 0666, static_cast<unsigned>(count));
+        // POSIX semaphore names must start with "/" on some platforms (e.g., FreeBSD)
+        // Use a separate namespace for semaphores to avoid conflicts with shm
+        if (name[0] == '/') {
+            sem_name_ = std::string(name) + "_sem";
+        } else {
+            sem_name_ = std::string("/") + name + "_sem";
+        }
+        h_ = ::sem_open(sem_name_.c_str(), O_CREAT, 0666, static_cast<unsigned>(count));
         if (h_ == SEM_FAILED) {
-            ipc::error("fail sem_open[%d]: %s\n", errno, name);
+            ipc::error("fail sem_open[%d]: %s\n", errno, sem_name_.c_str());
             return false;
         }
         return true;
@@ -52,14 +60,14 @@ class semaphore {
             ipc::error("fail sem_close[%d]: %s\n", errno);
         }
         h_ = SEM_FAILED;
-        if (shm_.name() != nullptr) {
-            std::string name = shm_.name();
+        if (!sem_name_.empty() && shm_.name() != nullptr) {
             if (shm_.release() <= 1) {
-                if (::sem_unlink(name.c_str()) != 0) {
-                    ipc::error("fail sem_unlink[%d]: %s, name: %s\n", errno, name.c_str());
+                if (::sem_unlink(sem_name_.c_str()) != 0) {
+                    ipc::error("fail sem_unlink[%d]: %s, name: %s\n", errno, sem_name_.c_str());
                 }
             }
         }
+        sem_name_.clear();
     }
 
     void clear() noexcept {
@@ -69,14 +77,22 @@ class semaphore {
             }
             h_ = SEM_FAILED;
         }
-        char const *name = shm_.name();
-        if (name == nullptr) return;
-        ::sem_unlink(name);
+        if (!sem_name_.empty()) {
+            ::sem_unlink(sem_name_.c_str());
+            sem_name_.clear();
+        }
         shm_.clear(); // Make sure the storage is cleaned up.
     }
 
     static void clear_storage(char const *name) noexcept {
-        ::sem_unlink(name);
+        // Construct the semaphore name same way as open() does
+        std::string sem_name;
+        if (name[0] == '/') {
+            sem_name = std::string(name) + "_sem";
+        } else {
+            sem_name = std::string("/") + name + "_sem";
+        }
+        ::sem_unlink(sem_name.c_str());
         ipc::shm::handle::clear_storage(name);
     }