1 //
2 // Copyright (C) 2014 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 "trunks/tpm_handle.h"
18
19 #include <fcntl.h>
20 #include <unistd.h>
21
22 #include <base/callback.h>
23 #include <base/logging.h>
24 #include <base/posix/eintr_wrapper.h>
25
26 namespace {
27
28 const char kTpmDevice[] = "/dev/tpm0";
29 const uint32_t kTpmBufferSize = 4096;
30 const int kInvalidFileDescriptor = -1;
31
32 } // namespace
33
34 namespace trunks {
35
TpmHandle()36 TpmHandle::TpmHandle() : fd_(kInvalidFileDescriptor) {}
37
~TpmHandle()38 TpmHandle::~TpmHandle() {
39 int result = IGNORE_EINTR(close(fd_));
40 if (result == -1) {
41 PLOG(ERROR) << "TPM: couldn't close " << kTpmDevice;
42 }
43 LOG(INFO) << "TPM: " << kTpmDevice << " closed successfully";
44 }
45
Init()46 bool TpmHandle::Init() {
47 if (fd_ != kInvalidFileDescriptor) {
48 VLOG(1) << "Tpm already initialized.";
49 return true;
50 }
51 fd_ = HANDLE_EINTR(open(kTpmDevice, O_RDWR));
52 if (fd_ == kInvalidFileDescriptor) {
53 PLOG(ERROR) << "TPM: Error opening tpm0 file descriptor at " << kTpmDevice;
54 return false;
55 }
56 LOG(INFO) << "TPM: " << kTpmDevice << " opened successfully";
57 return true;
58 }
59
SendCommand(const std::string & command,const ResponseCallback & callback)60 void TpmHandle::SendCommand(const std::string& command,
61 const ResponseCallback& callback) {
62 callback.Run(SendCommandAndWait(command));
63 }
64
SendCommandAndWait(const std::string & command)65 std::string TpmHandle::SendCommandAndWait(const std::string& command) {
66 std::string response;
67 TPM_RC result = SendCommandInternal(command, &response);
68 if (result != TPM_RC_SUCCESS) {
69 response = CreateErrorResponse(result);
70 }
71 return response;
72 }
73
SendCommandInternal(const std::string & command,std::string * response)74 TPM_RC TpmHandle::SendCommandInternal(const std::string& command,
75 std::string* response) {
76 CHECK_NE(fd_, kInvalidFileDescriptor);
77 int result = HANDLE_EINTR(write(fd_, command.data(), command.length()));
78 if (result < 0) {
79 PLOG(ERROR) << "TPM: Error writing to TPM handle.";
80 return TRUNKS_RC_WRITE_ERROR;
81 }
82 if (static_cast<size_t>(result) != command.length()) {
83 LOG(ERROR) << "TPM: Error writing to TPM handle: " << result << " vs "
84 << command.length();
85 return TRUNKS_RC_WRITE_ERROR;
86 }
87 char response_buf[kTpmBufferSize];
88 result = HANDLE_EINTR(read(fd_, response_buf, kTpmBufferSize));
89 if (result < 0) {
90 PLOG(ERROR) << "TPM: Error reading from TPM handle.";
91 return TRUNKS_RC_READ_ERROR;
92 }
93 response->assign(response_buf, static_cast<size_t>(result));
94 return TPM_RC_SUCCESS;
95 }
96
97 } // namespace trunks
98