The Tor Browser: ipc/glue/SharedMemorySysV.h@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-

     2  * vim: sw=2 ts=8 et :

     3  */

     4 /* This Source Code Form is subject to the terms of the Mozilla Public

     5  * License, v. 2.0. If a copy of the MPL was not distributed with this

     6  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     8 #ifndef mozilla_ipc_SharedMemorySysV_h

     9 #define mozilla_ipc_SharedMemorySysV_h

    11 #if (defined(OS_LINUX) && !defined(ANDROID)) || defined(OS_BSD)

    13 // SysV shared memory isn't available on Windows, but we define the

    14 // following macro so that #ifdefs are clearer (compared to #ifdef

    15 // OS_LINUX).

    16 #define MOZ_HAVE_SHAREDMEMORYSYSV

    18 #include "SharedMemory.h"

    20 #include "nsDebug.h"

    22 #include <errno.h>

    23 #include <fcntl.h>

    24 #include <stdio.h>

    25 #include <string.h>

    26 #include <sys/ipc.h>

    27 #include <sys/shm.h>

    29 //

    30 // This is a low-level wrapper around platform shared memory.  Don't

    31 // use it directly; use Shmem allocated through IPDL interfaces.

    32 //

    34 namespace mozilla {

    35 namespace ipc {

    38 class SharedMemorySysV : public SharedMemory

    39 {

    40 public:

    41   typedef int Handle;

    43   SharedMemorySysV() :

    44     mHandle(-1),

    45     mData(nullptr)

    46   {

    47   }

    49   SharedMemorySysV(Handle aHandle) :

    50     mHandle(aHandle),

    51     mData(nullptr)

    52   {

    53   }

    55   virtual ~SharedMemorySysV()

    56   {

    57     shmdt(mData);

    58     mHandle = -1;

    59     mData = nullptr;

    60   }

    62   virtual bool Create(size_t aNbytes) MOZ_OVERRIDE

    63   {

    64     int id = shmget(IPC_PRIVATE, aNbytes, IPC_CREAT | 0600);

    65     if (id == -1)

    66       return false;

    68     mHandle = id;

    69     mAllocSize = aNbytes;

    70     Created(aNbytes);

    72     return Map(aNbytes);

    73   }

    75   virtual bool Map(size_t nBytes) MOZ_OVERRIDE

    76   {

    77     // already mapped

    78     if (mData)

    79       return true;

    81     if (!IsHandleValid(mHandle))

    82       return false;

    84     void* mem = shmat(mHandle, nullptr, 0);

    85     if (mem == (void*) -1) {

    86       char warning[256];

    87       ::snprintf(warning, sizeof(warning)-1,

    88                  "shmat(): %s (%d)\n", strerror(errno), errno);

    90       NS_WARNING(warning);

    92       return false;

    93     }

    95     // Mark the handle as deleted so that, should this process go away, the

    96     // segment is cleaned up.

    97     shmctl(mHandle, IPC_RMID, 0);

    99     mData = mem;

   101 #ifdef DEBUG

   102     struct shmid_ds info;

   103     if (shmctl(mHandle, IPC_STAT, &info) < 0)

   104       return false;

   106     NS_ABORT_IF_FALSE(nBytes <= info.shm_segsz,

   107                       "Segment doesn't have enough space!");

   108 #endif

   110     Mapped(nBytes);

   111     return true;

   112   }

   114   virtual void* memory() const MOZ_OVERRIDE

   115   {

   116     return mData;

   117   }

   119   virtual SharedMemoryType Type() const MOZ_OVERRIDE

   120   {

   121     return TYPE_SYSV;

   122   }

   124   Handle GetHandle() const

   125   {

   126     NS_ABORT_IF_FALSE(IsHandleValid(mHandle), "invalid handle");

   127     return mHandle;

   128   }

   130   static Handle NULLHandle()

   131   {

   132     return -1;

   133   }

   135   static bool IsHandleValid(Handle aHandle)

   136   {

   137     return aHandle != -1;

   138   }

   140 private:

   141   Handle mHandle;

   142   void* mData;

   143 };

   145 } // namespace ipc

   146 } // namespace mozilla

   148 #endif // OS_LINUX

   150 #endif // ifndef mozilla_ipc_SharedMemorySysV_h

The Tor Browser / file revision