1 /*
2 * Copyright (C) 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "src/perfetto_cmd/packet_writer.h"
18
19 #include <array>
20
21 #include <fcntl.h>
22 #include <signal.h>
23 #include <stdio.h>
24 #include <sys/stat.h>
25
26 #include "perfetto/base/build_config.h"
27 #include "perfetto/ext/base/getopt.h"
28 #include "perfetto/ext/base/paged_memory.h"
29 #include "perfetto/ext/base/utils.h"
30 #include "perfetto/ext/tracing/core/trace_packet.h"
31 #include "perfetto/protozero/proto_utils.h"
32 #include "protos/perfetto/trace/trace.pbzero.h"
33
34 namespace perfetto {
35 namespace {
36
37 using protozero::proto_utils::MakeTagLengthDelimited;
38 using protozero::proto_utils::WriteVarInt;
39 using Preamble = std::array<char, 16>;
40
41 template <uint32_t id>
GetPreamble(size_t sz,Preamble * preamble)42 size_t GetPreamble(size_t sz, Preamble* preamble) {
43 uint8_t* ptr = reinterpret_cast<uint8_t*>(preamble->data());
44 constexpr uint32_t tag = MakeTagLengthDelimited(id);
45 ptr = WriteVarInt(tag, ptr);
46 ptr = WriteVarInt(sz, ptr);
47 size_t preamble_size = reinterpret_cast<uintptr_t>(ptr) -
48 reinterpret_cast<uintptr_t>(preamble->data());
49 PERFETTO_DCHECK(preamble_size < preamble->size());
50 return preamble_size;
51 }
52
53 } // namespace
54
~PacketWriter()55 PacketWriter::~PacketWriter() {
56 fflush(fd_);
57 }
58
WritePacket(const TracePacket & packet)59 bool PacketWriter::WritePacket(const TracePacket& packet) {
60 Preamble preamble;
61 size_t size = GetPreamble<protos::pbzero::Trace::kPacketFieldNumber>(
62 packet.size(), &preamble);
63 if (fwrite(preamble.data(), 1, size, fd_) != size)
64 return false;
65 for (const Slice& slice : packet.slices()) {
66 if (fwrite(reinterpret_cast<const char*>(slice.start), 1, slice.size,
67 fd_) != slice.size) {
68 return false;
69 }
70 }
71
72 return true;
73 }
74
75 } // namespace perfetto
76