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