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/*
* Copyright (C) 2012 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 specific language governing permissions and
* limitations under the License.
*/
#include "kernel_warning_collector.h"
#include <base/files/file_util.h>
#include <base/logging.h>
#include <base/strings/string_number_conversions.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
namespace {
const char kExecName[] = "kernel-warning";
const char kKernelWarningSignatureKey[] = "sig";
const char kKernelWarningPath[] = "/var/run/kwarn/warning";
const pid_t kKernelPid = 0;
const uid_t kRootUid = 0;
} // namespace
using base::FilePath;
using base::StringPrintf;
KernelWarningCollector::KernelWarningCollector() {
}
KernelWarningCollector::~KernelWarningCollector() {
}
bool KernelWarningCollector::LoadKernelWarning(std::string *content,
std::string *signature) {
FilePath kernel_warning_path(kKernelWarningPath);
if (!base::ReadFileToString(kernel_warning_path, content)) {
LOG(ERROR) << "Could not open " << kKernelWarningPath;
return false;
}
// The signature is in the first line.
std::string::size_type end_position = content->find('\n');
if (end_position == std::string::npos) {
LOG(ERROR) << "unexpected kernel warning format";
return false;
}
*signature = content->substr(0, end_position);
return true;
}
bool KernelWarningCollector::Collect() {
std::string reason = "normal collection";
bool feedback = true;
if (IsDeveloperImage()) {
reason = "always collect from developer builds";
feedback = true;
} else if (!is_feedback_allowed_function_()) {
reason = "no user consent";
feedback = false;
}
LOG(INFO) << "Processing kernel warning: " << reason;
if (!feedback) {
return true;
}
std::string kernel_warning;
std::string warning_signature;
if (!LoadKernelWarning(&kernel_warning, &warning_signature)) {
return true;
}
FilePath root_crash_directory;
if (!GetCreatedCrashDirectoryByEuid(kRootUid, &root_crash_directory,
nullptr)) {
return true;
}
std::string dump_basename =
FormatDumpBasename(kExecName, time(nullptr), kKernelPid);
FilePath kernel_crash_path = root_crash_directory.Append(
StringPrintf("%s.kcrash", dump_basename.c_str()));
// We must use WriteNewFile instead of base::WriteFile as we
// do not want to write with root access to a symlink that an attacker
// might have created.
if (WriteNewFile(kernel_crash_path,
kernel_warning.data(),
kernel_warning.length()) !=
static_cast<int>(kernel_warning.length())) {
LOG(INFO) << "Failed to write kernel warning to "
<< kernel_crash_path.value().c_str();
return true;
}
AddCrashMetaData(kKernelWarningSignatureKey, warning_signature);
WriteCrashMetaData(
root_crash_directory.Append(
StringPrintf("%s.meta", dump_basename.c_str())),
kExecName, kernel_crash_path.value());
LOG(INFO) << "Stored kernel warning into " << kernel_crash_path.value();
return true;
}
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