ipc/glue/FileDescriptorUtils.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "FileDescriptorUtils.h"
   8
   9 #include "nsIEventTarget.h"
  10
  11 #include "nsCOMPtr.h"
  12 #include "nsDebug.h"
  13 #include "nsNetCID.h"
  14 #include "nsServiceManagerUtils.h"
  15 #include "prio.h"
  16 #include "private/pprio.h"
  17
  18 #include <errno.h>
  19 #ifdef XP_WIN
  20 #  include <io.h>
  21 #else
  22 #  include <unistd.h>
  23 #endif
  24
  25 using mozilla::ipc::CloseFileRunnable;
  26
  27 CloseFileRunnable::CloseFileRunnable(const FileDescriptor& aFileDescriptor)
  28     : Runnable("CloseFileRunnable"), mFileDescriptor(aFileDescriptor) {
  29   MOZ_ASSERT(aFileDescriptor.IsValid());
  30 }
  31
  32 CloseFileRunnable::~CloseFileRunnable() {
  33   if (mFileDescriptor.IsValid()) {
  34     // It's probably safer to take the main thread IO hit here rather than leak
  35     // the file descriptor.
  36     CloseFile();
  37   }
  38 }
  39
  40 NS_IMPL_ISUPPORTS_INHERITED0(CloseFileRunnable, Runnable)
  41
  42 void CloseFileRunnable::Dispatch() {
  43   nsCOMPtr<nsIEventTarget> eventTarget =
  44       do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
  45   NS_ENSURE_TRUE_VOID(eventTarget);
  46
  47   nsresult rv = eventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
  48   NS_ENSURE_SUCCESS_VOID(rv);
  49 }
  50
  51 void CloseFileRunnable::CloseFile() {
  52   // It's possible for this to happen on the main thread if the dispatch to the
  53   // stream service fails so we can't assert the thread on which we're running.
  54   mFileDescriptor = FileDescriptor();
  55 }
  56
  57 NS_IMETHODIMP
  58 CloseFileRunnable::Run() {
  59   MOZ_ASSERT(!NS_IsMainThread());
  60
  61   CloseFile();
  62   return NS_OK;
  63 }
  64
  65 namespace mozilla {
  66 namespace ipc {
  67
  68 FILE* FileDescriptorToFILE(const FileDescriptor& aDesc, const char* aOpenMode) {
  69   if (!aDesc.IsValid()) {
  70     errno = EBADF;
  71     return nullptr;
  72   }
  73   auto handle = aDesc.ClonePlatformHandle();
  74 #ifdef XP_WIN
  75   int fd = _open_osfhandle(static_cast<intptr_t>(handle.get()), 0);
  76   if (fd == -1) {
  77     return nullptr;
  78   }
  79   Unused << handle.release();
  80 #else
  81   int fd = handle.release();
  82 #endif
  83   FILE* file = fdopen(fd, aOpenMode);
  84   if (!file) {
  85     int saved_errno = errno;
  86     close(fd);
  87     errno = saved_errno;
  88   }
  89   return file;
  90 }
  91
  92 FileDescriptor FILEToFileDescriptor(FILE* aStream) {
  93   if (!aStream) {
  94     errno = EBADF;
  95     return FileDescriptor();
  96   }
  97 #ifdef XP_WIN
  98   int fd = _fileno(aStream);
  99   if (fd == -1) {
 100     return FileDescriptor();
 101   }
 102   return FileDescriptor(reinterpret_cast<HANDLE>(_get_osfhandle(fd)));
 103 #else
 104   return FileDescriptor(fileno(aStream));
 105 #endif
 106 }
 107
 108 }  // namespace ipc
 109 }  // namespace mozilla