src/Bpf.cpp

/*
 * Copyright (C) 2023 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.
 */

#define LOG_TAG "uprobestats"

#include <BpfSyscallWrappers.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <linux/perf_event.h>

#include <string>

#include "bpf/BpfMap.h"
#include "bpf/BpfRingbuf.h"

#include "Bpf.h"

namespace android {
namespace uprobestats {
namespace bpf {

const char *PMU_TYPE_FILE = "/sys/bus/event_source/devices/uprobe/type";

int bpfPerfEventOpen(const char *filename, int offset, int pid,
                     const char *bpfProgramPath) {
  android::base::unique_fd bpfProgramFd(
      android::bpf::retrieveProgram(bpfProgramPath));
  if (bpfProgramFd < 0) {
    LOG(ERROR) << "retrieveProgram failed";
    return -1;
  }

  std::string typeStr;
  if (!android::base::ReadFileToString(PMU_TYPE_FILE, &typeStr)) {
    LOG(ERROR) << "Failed to open pmu type file";
    return -1;
  }
  int pmu_type = (int)strtol(typeStr.c_str(), NULL, 10);

  struct perf_event_attr attr = {};
  attr.sample_period = 1;
  attr.wakeup_events = 1;
  attr.config2 = offset;
  attr.size = sizeof(attr);
  attr.type = pmu_type;
  attr.config1 = android::bpf::ptr_to_u64((void *)filename);
  attr.exclude_kernel = true;

  int perfEventFd = syscall(__NR_perf_event_open, &attr, pid, /*cpu=*/-1,
                            /* group_fd=*/-1, PERF_FLAG_FD_CLOEXEC);
  if (perfEventFd < 0) {
    LOG(ERROR) << "syscall(__NR_perf_event_open) failed. "
               << "perfEventFd: " << perfEventFd << " "
               << "error: " << strerror(errno);
    return -1;
  }
  if (ioctl(perfEventFd, PERF_EVENT_IOC_SET_BPF, int(bpfProgramFd)) < 0) {
    LOG(ERROR) << "PERF_EVENT_IOC_SET_BPF failed. " << strerror(errno);
    return -1;
  }
  if (ioctl(perfEventFd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
    LOG(ERROR) << "PERF_EVENT_IOC_ENABLE failed. " << strerror(errno);
    return -1;
  }
  return 0;
}

template <typename T>
std::vector<T> pollRingBuf(const char *mapPath, int timeoutMs) {
  auto result = android::bpf::BpfRingbuf<T>::Create(mapPath);
  std::vector<T> vec;
  if (!result.value()->wait(timeoutMs)) {
    return vec;
  }
  auto callback = [&](const T &value) { vec.push_back(value); };
  result.value()->ConsumeAll(callback);
  return vec;
}

template std::vector<uint64_t> pollRingBuf(const char *mapPath, int timeoutMs);
template std::vector<CallResult> pollRingBuf(const char *mapPath,
                                             int timeoutMs);
template std::vector<CallTimestamp> pollRingBuf(const char *mapPath,
                                                int timeoutMs);
template std::vector<SetUidTempAllowlistStateRecord>
pollRingBuf(const char *mapPath, int timeoutMs);

std::vector<int32_t> consumeRingBuf(const char *mapPath) {
  auto result = android::bpf::BpfRingbuf<uint64_t>::Create(mapPath);
  std::vector<int32_t> vec;
  auto callback = [&](const uint64_t &value) { vec.push_back(value); };
  result.value()->ConsumeAll(callback);
  return vec;
}

void printRingBuf(const char *mapPath) {
  auto result = android::bpf::BpfRingbuf<uint64_t>::Create(mapPath);
  auto callback = [&](const uint64_t &value) {
    LOG(INFO) << "ringbuf result callback. value: " << value
              << " mapPath: " << mapPath;
  };
  int numConsumed = result.value()->ConsumeAll(callback).value_or(-1);
  LOG(INFO) << "ring buffer size: " << numConsumed << " mapPath: " << mapPath;
}

} // namespace bpf
} // namespace uprobestats
} // namespace android