diff options
Diffstat (limited to 'base/shared_memory.h')
| -rw-r--r-- | base/shared_memory.h | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/base/shared_memory.h b/base/shared_memory.h index d96299a..ede36c5 100644 --- a/base/shared_memory.h +++ b/base/shared_memory.h @@ -24,11 +24,9 @@ typedef HANDLE SharedMemoryHandle; typedef HANDLE SharedMemoryLock; #elif defined(OS_POSIX) typedef int SharedMemoryHandle; -// TODO(port): these semaphores can leak if we crash, causing -// autobuilder problems. Transition to something easier to clean up -// (e.g. lockf/flock). -// TODO(port): make sure what we transition to is fast enough. -typedef sem_t* SharedMemoryLock; +// On POSIX, the lock is implemented as a lockf() on the mapped file, +// so no additional member (or definition of SharedMemoryLock) is +// needed. #endif // Platform abstraction for shared memory. Provides a C++ wrapper @@ -123,6 +121,12 @@ class SharedMemory { // Lock the shared memory. // This is a cross-process lock which may be recursively // locked by the same thread. + // TODO(port): + // WARNING: on POSIX the lock only works across processes, not + // across threads. 2 threads in the same process can both grab the + // lock at the same time. There are several solutions for this + // (futex, lockf+anon_semaphore) but none are both clean and common + // across Mac and Linux. void Lock(); // Release the shared memory lock. @@ -133,6 +137,8 @@ class SharedMemory { bool CreateOrOpen(const std::wstring &name, int posix_flags, size_t size); bool FilenameForMemoryName(const std::wstring &memname, std::wstring *filename); + void LockOrUnlockCommon(int function); + #endif bool ShareToProcessCommon(ProcessHandle process, SharedMemoryHandle* new_handle, @@ -143,9 +149,8 @@ class SharedMemory { void* memory_; bool read_only_; size_t max_size_; +#if !defined(OS_POSIX) SharedMemoryLock lock_; -#if defined(OS_POSIX) - std::string sem_name_; #endif DISALLOW_EVIL_CONSTRUCTORS(SharedMemory); |