7f8e819ded
The CL adds utility functions to framework to parse FUSE messages from the kernel. The library will be used from framework JNI and service JNI. Bug: 32260320 Test: libappfuse_test Change-Id: Ib89b26d34789e6c26a3288beceb3ea145c1ae780
136 lines
4.4 KiB
C++
136 lines
4.4 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specic language governing permissions and
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* limitations under the License.
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*/
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#include "libappfuse/AppFuse.h"
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#include <inttypes.h>
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#include <string.h>
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#include <unistd.h>
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#include <algorithm>
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#include <android-base/logging.h>
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#include <android-base/macros.h>
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namespace android {
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template <typename T, typename Header>
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bool FuseMessage<T, Header>::CheckHeaderLength() const {
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if (sizeof(Header) <= header.len && header.len <= sizeof(T)) {
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return true;
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} else {
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LOG(ERROR) << "Packet size is invalid=" << header.len;
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return false;
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}
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}
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template <typename T, typename Header>
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bool FuseMessage<T, Header>::CheckResult(
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int result, const char* operation_name) const {
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if (result >= 0 && static_cast<uint32_t>(result) == header.len) {
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return true;
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} else {
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PLOG(ERROR) << "Failed to " << operation_name
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<< " a packet from FD. result=" << result << " header.len="
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<< header.len;
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return false;
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}
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}
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template <typename T, typename Header>
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bool FuseMessage<T, Header>::Read(int fd) {
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const ssize_t result = TEMP_FAILURE_RETRY(::read(fd, this, sizeof(T)));
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return CheckHeaderLength() && CheckResult(result, "read");
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}
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template <typename T, typename Header>
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bool FuseMessage<T, Header>::Write(int fd) const {
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if (!CheckHeaderLength()) {
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return false;
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}
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const ssize_t result = TEMP_FAILURE_RETRY(::write(fd, this, header.len));
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return CheckResult(result, "write");
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}
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template struct FuseMessage<FuseRequest, fuse_in_header>;
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template struct FuseMessage<FuseResponse, fuse_out_header>;
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void FuseResponse::ResetHeader(
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uint32_t data_length, int32_t error, uint64_t unique) {
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CHECK_LE(error, 0) << "error should be zero or negative.";
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header.len = sizeof(fuse_out_header) + data_length;
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header.error = error;
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header.unique = unique;
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}
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void FuseResponse::Reset(uint32_t data_length, int32_t error, uint64_t unique) {
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memset(this, 0, sizeof(fuse_out_header) + data_length);
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ResetHeader(data_length, error, unique);
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}
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void FuseBuffer::HandleInit() {
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const fuse_init_in* const in = &request.init_in;
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// Before writing |out|, we need to copy data from |in|.
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const uint64_t unique = request.header.unique;
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const uint32_t minor = in->minor;
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const uint32_t max_readahead = in->max_readahead;
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// Kernel 2.6.16 is the first stable kernel with struct fuse_init_out
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// defined (fuse version 7.6). The structure is the same from 7.6 through
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// 7.22. Beginning with 7.23, the structure increased in size and added
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// new parameters.
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if (in->major != FUSE_KERNEL_VERSION || in->minor < 6) {
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LOG(ERROR) << "Fuse kernel version mismatch: Kernel version " << in->major
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<< "." << in->minor << " Expected at least " << FUSE_KERNEL_VERSION
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<< ".6";
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response.Reset(0, -EPERM, unique);
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return;
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}
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// We limit ourselves to 15 because we don't handle BATCH_FORGET yet
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size_t response_size = sizeof(fuse_init_out);
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#if defined(FUSE_COMPAT_22_INIT_OUT_SIZE)
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// FUSE_KERNEL_VERSION >= 23.
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// If the kernel only works on minor revs older than or equal to 22,
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// then use the older structure size since this code only uses the 7.22
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// version of the structure.
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if (minor <= 22) {
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response_size = FUSE_COMPAT_22_INIT_OUT_SIZE;
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}
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#endif
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response.Reset(response_size, kFuseSuccess, unique);
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fuse_init_out* const out = &response.init_out;
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out->major = FUSE_KERNEL_VERSION;
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// We limit ourselves to 15 because we don't handle BATCH_FORGET yet.
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out->minor = std::min(minor, 15u);
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out->max_readahead = max_readahead;
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out->flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES;
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out->max_background = 32;
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out->congestion_threshold = 32;
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out->max_write = kFuseMaxWrite;
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}
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void FuseBuffer::HandleNotImpl() {
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LOG(VERBOSE) << "NOTIMPL op=" << request.header.opcode << " uniq="
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<< request.header.unique << " nid=" << request.header.nodeid;
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const uint64_t unique = request.header.unique;
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response.Reset(0, -ENOSYS, unique);
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}
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} // namespace android
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