platform_system_core/libappfuse/FuseBridgeLoop.cc

102 lines
2.6 KiB
C++

/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specic language governing permissions and
* limitations under the License.
*/
#include "libappfuse/FuseBridgeLoop.h"
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
namespace android {
namespace fuse {
bool StartFuseBridgeLoop(
int raw_dev_fd, int raw_proxy_fd, FuseBridgeLoopCallback* callback) {
base::unique_fd dev_fd(raw_dev_fd);
base::unique_fd proxy_fd(raw_proxy_fd);
FuseBuffer buffer;
size_t open_count = 0;
LOG(DEBUG) << "Start fuse loop.";
while (true) {
if (!buffer.request.Read(dev_fd)) {
return false;
}
const uint32_t opcode = buffer.request.header.opcode;
LOG(VERBOSE) << "Read a fuse packet, opcode=" << opcode;
switch (opcode) {
case FUSE_FORGET:
// Do not reply to FUSE_FORGET.
continue;
case FUSE_LOOKUP:
case FUSE_GETATTR:
case FUSE_OPEN:
case FUSE_READ:
case FUSE_WRITE:
case FUSE_RELEASE:
case FUSE_FSYNC:
if (!buffer.request.Write(proxy_fd)) {
LOG(ERROR) << "Failed to write a request to the proxy.";
return false;
}
if (!buffer.response.Read(proxy_fd)) {
LOG(ERROR) << "Failed to read a response from the proxy.";
return false;
}
break;
case FUSE_INIT:
buffer.HandleInit();
break;
default:
buffer.HandleNotImpl();
break;
}
if (!buffer.response.Write(dev_fd)) {
LOG(ERROR) << "Failed to write a response to the device.";
return false;
}
switch (opcode) {
case FUSE_INIT:
callback->OnMount();
break;
case FUSE_OPEN:
if (buffer.response.header.error == fuse::kFuseSuccess) {
open_count++;
}
break;
case FUSE_RELEASE:
if (open_count != 0) {
open_count--;
} else {
LOG(WARNING) << "Unexpected FUSE_RELEASE before opening a file.";
break;
}
if (open_count == 0) {
return true;
}
break;
}
}
}
} // namespace fuse
} // namespace android