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/*
* Copyright (C) 2015 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 "event_fd.h"
#include <fcntl.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <memory>
#include <base/logging.h>
#include <base/stringprintf.h>
#include "event_type.h"
#include "event_attr.h"
#include "perf_event.h"
#include "utils.h"
static int perf_event_open(perf_event_attr* attr, pid_t pid, int cpu, int group_fd,
unsigned long flags) {
return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
}
std::unique_ptr<EventFd> EventFd::OpenEventFileForProcess(const EventAttr& attr, pid_t pid) {
return OpenEventFile(attr, pid, -1);
}
std::unique_ptr<EventFd> EventFd::OpenEventFileForCpu(const EventAttr& attr, int cpu) {
return OpenEventFile(attr, -1, cpu);
}
std::unique_ptr<EventFd> EventFd::OpenEventFile(const EventAttr& attr, pid_t pid, int cpu) {
perf_event_attr perf_attr = attr.Attr();
std::string event_name = "unknown event";
const EventType* event_type =
EventTypeFactory::FindEventTypeByConfig(perf_attr.type, perf_attr.config);
if (event_type != nullptr) {
event_name = event_type->name;
}
int perf_event_fd = perf_event_open(&perf_attr, pid, cpu, -1, 0);
if (perf_event_fd == -1) {
// It depends whether the perf_event_file configuration is supported by the kernel and the
// machine. So fail to open the file is not an error.
PLOG(DEBUG) << "open perf_event_file (event " << event_name << ", pid " << pid << ", cpu "
<< cpu << ") failed";
return nullptr;
}
if (fcntl(perf_event_fd, F_SETFD, FD_CLOEXEC) == -1) {
PLOG(ERROR) << "fcntl(FD_CLOEXEC) for perf_event_file (event " << event_name << ", pid " << pid
<< ", cpu " << cpu << ") failed";
return nullptr;
}
return std::unique_ptr<EventFd>(new EventFd(perf_event_fd, event_name, pid, cpu));
}
EventFd::~EventFd() {
close(perf_event_fd_);
}
std::string EventFd::Name() const {
return android::base::StringPrintf("perf_event_file(event %s, pid %d, cpu %d)",
event_name_.c_str(), pid_, cpu_);
}
bool EventFd::EnableEvent() {
int result = ioctl(perf_event_fd_, PERF_EVENT_IOC_ENABLE, 0);
if (result < 0) {
PLOG(ERROR) << "ioctl(enable) " << Name() << " failed";
return false;
}
return true;
}
bool EventFd::DisableEvent() {
int result = ioctl(perf_event_fd_, PERF_EVENT_IOC_DISABLE, 0);
if (result < 0) {
PLOG(ERROR) << "ioctl(disable) " << Name() << " failed";
return false;
}
return true;
}
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