ppapi/nacl_irt/manifest_service.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ppapi/nacl_irt/manifest_service.h"
   6
   7 #include "base/message_loop/message_loop_proxy.h"
   8 #include "ipc/ipc_channel_handle.h"
   9 #include "ipc/ipc_channel_proxy.h"
  10 #include "ipc/ipc_sync_message_filter.h"
  11 #include "native_client/src/trusted/service_runtime/include/sys/errno.h"
  12 #include "ppapi/nacl_irt/irt_manifest.h"
  13 #include "ppapi/nacl_irt/plugin_startup.h"
  14 #include "ppapi/proxy/ppapi_messages.h"
  15
  16 namespace ppapi {
  17
  18 const char kFilePrefix[] = "files/";
  19
  20 // IPC channel is asynchronously set up. So, the NaCl process may try to
  21 // send a OpenResource message to the host before the connection is
  22 // established. In such a case, it is necessary to wait for the set up
  23 // completion.
  24 class ManifestMessageFilter : public IPC::SyncMessageFilter {
  25  public:
  26   ManifestMessageFilter(base::WaitableEvent* shutdown_event)
  27       : SyncMessageFilter(shutdown_event),
  28         connected_event_(
  29             true /* manual_reset */, false /* initially_signaled */) {
  30   }
  31
  32   virtual bool Send(IPC::Message* message) override {
  33     // Wait until set up is actually done.
  34     connected_event_.Wait();
  35     return SyncMessageFilter::Send(message);
  36   }
  37
  38   // When set up is done, OnFilterAdded is called on IO thread. Unblocks the
  39   // Send().
  40   virtual void OnFilterAdded(IPC::Sender* sender) override {
  41     SyncMessageFilter::OnFilterAdded(sender);
  42     connected_event_.Signal();
  43   }
  44
  45   // If an error is found, unblocks the Send(), too, to return an error.
  46   virtual void OnChannelError() override {
  47     SyncMessageFilter::OnChannelError();
  48     connected_event_.Signal();
  49   }
  50
  51   // Similar to OnChannelError, unblocks the Send() on the channel closing.
  52   virtual void OnChannelClosing() override {
  53     SyncMessageFilter::OnChannelClosing();
  54     connected_event_.Signal();
  55   }
  56
  57  private:
  58   base::WaitableEvent connected_event_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(ManifestMessageFilter);
  61 };
  62
  63 ManifestService::ManifestService(
  64     const IPC::ChannelHandle& handle,
  65     scoped_refptr<base::MessageLoopProxy> io_message_loop,
  66     base::WaitableEvent* shutdown_event) {
  67   filter_ = new ManifestMessageFilter(shutdown_event);
  68   channel_ = IPC::ChannelProxy::Create(handle,
  69                                        IPC::Channel::MODE_SERVER,
  70                                        NULL,  // Listener
  71                                        io_message_loop.get());
  72   channel_->AddFilter(filter_.get());
  73 }
  74
  75 ManifestService::~ManifestService() {
  76 }
  77
  78 void ManifestService::StartupInitializationComplete() {
  79   filter_->Send(new PpapiHostMsg_StartupInitializationComplete);
  80 }
  81
  82 bool ManifestService::OpenResource(const char* file, int* fd) {
  83   // We currently restrict to only allow one concurrent open_resource() call
  84   // per plugin. This could be fixed by doing a token lookup with
  85   // NaClProcessMsg_ResolveFileTokenAsyncReply instead of using a
  86   // global inside components/nacl/loader/nacl_listener.cc
  87   base::AutoLock lock(open_resource_lock_);
  88
  89   // OpenResource will return INVALID SerializedHandle, if it is not supported.
  90   // Specifically, PNaCl doesn't support open resource.
  91   ppapi::proxy::SerializedHandle ipc_fd;
  92
  93   // File tokens are ignored here, but needed when the message is processed
  94   // inside NaClIPCAdapter.
  95   uint64_t file_token_lo = 0;
  96   uint64_t file_token_hi = 0;
  97   if (!filter_->Send(new PpapiHostMsg_OpenResource(
  98           std::string(kFilePrefix) + file,
  99           &ipc_fd,
 100           &file_token_lo,
 101           &file_token_hi))) {
 102     LOG(ERROR) << "ManifestService::OpenResource failed:" << file;
 103     *fd = -1;
 104     return false;
 105   }
 106
 107   // File tokens are used internally by NaClIPCAdapter and should have
 108   // been cleared from the message when it is received here.
 109   // These tokens should never be set for Non-SFI mode.
 110   CHECK(file_token_lo == 0);
 111   CHECK(file_token_hi == 0);
 112
 113   // Copy the file if we received a valid file descriptor. Otherwise, if we got
 114   // a reply, the file doesn't exist, so provide an fd of -1.
 115   // See IrtOpenResource() for how this function's result is interpreted.
 116   if (ipc_fd.is_file())
 117     *fd = ipc_fd.descriptor().fd;
 118   else
 119     *fd = -1;
 120   return true;
 121 }
 122
 123 int IrtOpenResource(const char* file, int* fd) {
 124   // Remove leading '/' character.
 125   if (file[0] == '/')
 126     ++file;
 127
 128   ManifestService* manifest_service = GetManifestService();
 129   if (manifest_service == NULL ||
 130       !manifest_service->OpenResource(file, fd)) {
 131     return NACL_ABI_EIO;
 132   }
 133   return (*fd == -1) ? NACL_ABI_ENOENT : 0;
 134 }
 135
 136 }  // namespace ppapi