michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * vim: sw=2 ts=8 et :
michael@0:  */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_ipc_SharedMemorySysV_h
michael@0: #define mozilla_ipc_SharedMemorySysV_h
michael@0: 
michael@0: #if (defined(OS_LINUX) && !defined(ANDROID)) || defined(OS_BSD)
michael@0: 
michael@0: // SysV shared memory isn't available on Windows, but we define the
michael@0: // following macro so that #ifdefs are clearer (compared to #ifdef
michael@0: // OS_LINUX).
michael@0: #define MOZ_HAVE_SHAREDMEMORYSYSV
michael@0: 
michael@0: #include "SharedMemory.h"
michael@0: 
michael@0: #include "nsDebug.h"
michael@0: 
michael@0: #include <errno.h>
michael@0: #include <fcntl.h>
michael@0: #include <stdio.h>
michael@0: #include <string.h>
michael@0: #include <sys/ipc.h>
michael@0: #include <sys/shm.h>
michael@0: 
michael@0: //
michael@0: // This is a low-level wrapper around platform shared memory.  Don't
michael@0: // use it directly; use Shmem allocated through IPDL interfaces.
michael@0: //
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace ipc {
michael@0: 
michael@0: 
michael@0: class SharedMemorySysV : public SharedMemory
michael@0: {
michael@0: public:
michael@0:   typedef int Handle;
michael@0: 
michael@0:   SharedMemorySysV() :
michael@0:     mHandle(-1),
michael@0:     mData(nullptr)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   SharedMemorySysV(Handle aHandle) :
michael@0:     mHandle(aHandle),
michael@0:     mData(nullptr)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   virtual ~SharedMemorySysV()
michael@0:   {
michael@0:     shmdt(mData);
michael@0:     mHandle = -1;
michael@0:     mData = nullptr;
michael@0:   }
michael@0: 
michael@0:   virtual bool Create(size_t aNbytes) MOZ_OVERRIDE
michael@0:   {
michael@0:     int id = shmget(IPC_PRIVATE, aNbytes, IPC_CREAT | 0600);
michael@0:     if (id == -1)
michael@0:       return false;
michael@0: 
michael@0:     mHandle = id;
michael@0:     mAllocSize = aNbytes;
michael@0:     Created(aNbytes);
michael@0: 
michael@0:     return Map(aNbytes);
michael@0:   }
michael@0: 
michael@0:   virtual bool Map(size_t nBytes) MOZ_OVERRIDE
michael@0:   {
michael@0:     // already mapped
michael@0:     if (mData)
michael@0:       return true;
michael@0: 
michael@0:     if (!IsHandleValid(mHandle))
michael@0:       return false;
michael@0: 
michael@0:     void* mem = shmat(mHandle, nullptr, 0);
michael@0:     if (mem == (void*) -1) {
michael@0:       char warning[256];
michael@0:       ::snprintf(warning, sizeof(warning)-1,
michael@0:                  "shmat(): %s (%d)\n", strerror(errno), errno);
michael@0: 
michael@0:       NS_WARNING(warning);
michael@0: 
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     // Mark the handle as deleted so that, should this process go away, the
michael@0:     // segment is cleaned up.
michael@0:     shmctl(mHandle, IPC_RMID, 0);
michael@0: 
michael@0:     mData = mem;
michael@0: 
michael@0: #ifdef DEBUG
michael@0:     struct shmid_ds info;
michael@0:     if (shmctl(mHandle, IPC_STAT, &info) < 0)
michael@0:       return false;
michael@0: 
michael@0:     NS_ABORT_IF_FALSE(nBytes <= info.shm_segsz,
michael@0:                       "Segment doesn't have enough space!");
michael@0: #endif
michael@0: 
michael@0:     Mapped(nBytes);
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   virtual void* memory() const MOZ_OVERRIDE
michael@0:   {
michael@0:     return mData;
michael@0:   }
michael@0: 
michael@0:   virtual SharedMemoryType Type() const MOZ_OVERRIDE
michael@0:   {
michael@0:     return TYPE_SYSV;
michael@0:   }
michael@0: 
michael@0:   Handle GetHandle() const
michael@0:   {
michael@0:     NS_ABORT_IF_FALSE(IsHandleValid(mHandle), "invalid handle");
michael@0:     return mHandle;
michael@0:   }
michael@0: 
michael@0:   static Handle NULLHandle()
michael@0:   {
michael@0:     return -1;
michael@0:   }
michael@0: 
michael@0:   static bool IsHandleValid(Handle aHandle)
michael@0:   {
michael@0:     return aHandle != -1;
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   Handle mHandle;
michael@0:   void* mData;
michael@0: };
michael@0: 
michael@0: } // namespace ipc
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // OS_LINUX
michael@0: 
michael@0: #endif // ifndef mozilla_ipc_SharedMemorySysV_h