ipc/glue/FileDescriptorUtils.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "FileDescriptorUtils.h"
   6
   7 #include "nsIEventTarget.h"
   8
   9 #include "nsCOMPtr.h"
  10 #include "nsDebug.h"
  11 #include "nsNetCID.h"
  12 #include "nsServiceManagerUtils.h"
  13 #include "nsThreadUtils.h"
  14 #include "prio.h"
  15 #include "private/pprio.h"
  16
  17 #include <errno.h>
  18 #ifdef XP_WIN
  19 #include <io.h>
  20 #else
  21 #include <unistd.h>
  22 #endif
  23
  24 using mozilla::ipc::CloseFileRunnable;
  25
  26 #ifdef DEBUG
  27
  28 CloseFileRunnable::CloseFileRunnable(const FileDescriptor& aFileDescriptor)
  29 : mFileDescriptor(aFileDescriptor)
  30 {
  31   MOZ_ASSERT(aFileDescriptor.IsValid());
  32 }
  33
  34 #endif // DEBUG
  35
  36 CloseFileRunnable::~CloseFileRunnable()
  37 {
  38   if (mFileDescriptor.IsValid()) {
  39     // It's probably safer to take the main thread IO hit here rather than leak
  40     // the file descriptor.
  41     CloseFile();
  42   }
  43 }
  44
  45 NS_IMPL_ISUPPORTS(CloseFileRunnable, nsIRunnable)
  46
  47 void
  48 CloseFileRunnable::Dispatch()
  49 {
  50   nsCOMPtr<nsIEventTarget> eventTarget =
  51     do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
  52   NS_ENSURE_TRUE_VOID(eventTarget);
  53
  54   nsresult rv = eventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
  55   NS_ENSURE_SUCCESS_VOID(rv);
  56 }
  57
  58 void
  59 CloseFileRunnable::CloseFile()
  60 {
  61   // It's possible for this to happen on the main thread if the dispatch to the
  62   // stream service fails so we can't assert the thread on which we're running.
  63
  64   MOZ_ASSERT(mFileDescriptor.IsValid());
  65
  66   PRFileDesc* fd =
  67     PR_ImportFile(PROsfd(mFileDescriptor.PlatformHandle()));
  68   NS_WARN_IF_FALSE(fd, "Failed to import file handle!");
  69
  70   mFileDescriptor = FileDescriptor();
  71
  72   if (fd) {
  73     PR_Close(fd);
  74     fd = nullptr;
  75   }
  76 }
  77
  78 NS_IMETHODIMP
  79 CloseFileRunnable::Run()
  80 {
  81   MOZ_ASSERT(!NS_IsMainThread());
  82
  83   CloseFile();
  84   return NS_OK;
  85 }
  86
  87 namespace mozilla {
  88 namespace ipc {
  89
  90 FILE*
  91 FileDescriptorToFILE(const FileDescriptor& aDesc,
  92                      const char* aOpenMode)
  93 {
  94   // Debug builds check whether the handle was "used", even if it's
  95   // invalid, so that needs to happen first.
  96   FileDescriptor::PlatformHandleType handle = aDesc.PlatformHandle();
  97   if (!aDesc.IsValid()) {
  98     errno = EBADF;
  99     return nullptr;
 100   }
 101 #ifdef XP_WIN
 102   int fd = _open_osfhandle(reinterpret_cast<intptr_t>(handle), 0);
 103   if (fd == -1) {
 104     CloseHandle(handle);
 105     return nullptr;
 106   }
 107 #else
 108   int fd = handle;
 109 #endif
 110   FILE* file = fdopen(fd, aOpenMode);
 111   if (!file) {
 112     int saved_errno = errno;
 113     close(fd);
 114     errno = saved_errno;
 115   }
 116   return file;
 117 }
 118
 119 FileDescriptor
 120 FILEToFileDescriptor(FILE* aStream)
 121 {
 122   if (!aStream) {
 123     errno = EBADF;
 124     return FileDescriptor();
 125   }
 126 #ifdef XP_WIN
 127   int fd = _fileno(aStream);
 128   if (fd == -1) {
 129     return FileDescriptor();
 130   }
 131   return FileDescriptor(reinterpret_cast<HANDLE>(_get_osfhandle(fd)));
 132 #else
 133   return FileDescriptor(fileno(aStream));
 134 #endif
 135 }
 136
 137 } // namespace ipc
 138 } // namespace mozilla