text: /*
   * Copyright (c) 2017 Facebook, Inc.
   *
   * 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 <linux/perf_event.h>
  #include <linux/version.h>
  #include <unistd.h>
  #include <string>
  
  #include "BPF.h"
  #include "catch.hpp"
  
  TEST_CASE("test read perf event", "[bpf_perf_event]") {
  // The basic bpf_perf_event_read is supported since Kernel 4.3. However in that
  // version it only supported HARDWARE and RAW events. On the other hand, our
  // tests running on Jenkins won't have available HARDWARE counters since they
  // are running on VMs. The support of other types of events such as SOFTWARE are
  // only added since Kernel 4.13, hence we can only run the test since that.
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
    const std::string BPF_PROGRAM = R"(
      BPF_PERF_ARRAY(cnt, NUM_CPUS);
      BPF_HASH(val, int, u64, 1);
      BPF_HASH(ret, int, int, 1);
      BPF_HASH(counter, int, struct bpf_perf_event_value, 1);
  
      int on_sys_getuid(void *ctx) {
        int zero = 0;
  
        u64 v = cnt.perf_read(CUR_CPU_IDENTIFIER);
        if (((s64)v < 0) && ((s64)v > -256))
          return 0;
        val.update(&zero, &v);
      #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
        u32 cpu = bpf_get_smp_processor_id();
        struct bpf_perf_event_value c = {0};
        int r = cnt.perf_counter_value(cpu, &c, sizeof(c));
        ret.update(&zero, &r);
        counter.update(&zero, &c);
      #endif
        return 0;
      }
    )";
  
    ebpf::BPF bpf;
    ebpf::StatusTuple res(0);
    res = bpf.init(
        BPF_PROGRAM,
        {"-DNUM_CPUS=" + std::to_string(sysconf(_SC_NPROCESSORS_ONLN))}, {});
    REQUIRE(res.code() == 0);
    res =
        bpf.open_perf_event("cnt", PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK);
    REQUIRE(res.code() == 0);
    std::string getuid_fnname = bpf.get_syscall_fnname("getuid");
    res = bpf.attach_kprobe(getuid_fnname, "on_sys_getuid");
    REQUIRE(res.code() == 0);
    REQUIRE(getuid() >= 0);
    res = bpf.detach_kprobe(getuid_fnname);
    REQUIRE(res.code() == 0);
    res = bpf.close_perf_event("cnt");
    REQUIRE(res.code() == 0);
  
    auto val = bpf.get_hash_table<int, uint64_t>("val");
    REQUIRE(val[0] >= 0);
  #endif
  
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
    auto counter_table =
        bpf.get_hash_table<int, struct bpf_perf_event_value>("counter");
    auto counter = counter_table[0];
    auto ret = bpf.get_hash_table<int, int>("ret");
    REQUIRE(ret[0] == 0);
    REQUIRE(counter.counter >= 0);
    REQUIRE(counter.enabled > 0);
    REQUIRE(counter.running >= 0);
    REQUIRE(counter.running <= counter.enabled);
  #endif
  }
  
  TEST_CASE("test attach perf event", "[bpf_perf_event]") {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
    const std::string BPF_PROGRAM = R"(
      BPF_HASH(pid, int, u64, 1);
      BPF_HASH(ret, int, int, 1);
      BPF_HASH(counter, int, struct bpf_perf_event_value, 1);
  
      int on_event(void *ctx) {
        int zero = 0;
        
        u64 p = bpf_get_current_pid_tgid();
        pid.update(&zero, &p);
      #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
        struct bpf_perf_event_value c = {0};
        int r = bpf_perf_prog_read_value(ctx, &c, sizeof(c));
        ret.update(&zero, &r);
        counter.update(&zero, &c);
      #endif
        return 0;
      }
    )";
  
    ebpf::BPF bpf;
    ebpf::StatusTuple res(0);
    res = bpf.init(BPF_PROGRAM);
    REQUIRE(res.code() == 0);
    res = bpf.attach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK,
                                "on_event", 0, 1000);
    REQUIRE(res.code() == 0);
    sleep(1);
    res = bpf.detach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK);
    REQUIRE(res.code() == 0);
  
    auto pid = bpf.get_hash_table<int, uint64_t>("pid");
    REQUIRE(pid[0] >= 0);
  #endif
  
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
    auto counter_table =
        bpf.get_hash_table<int, struct bpf_perf_event_value>("counter");
    auto counter = counter_table[0];
    auto ret = bpf.get_hash_table<int, int>("ret");
    REQUIRE(ret[0] == 0);
    REQUIRE(counter.counter >= 0);
    // the program slept one second between perf_event attachment and detachment
    // in the above, so the enabled counter should be 1000000000ns or
    // more. But in reality, most of counters (if not all) are 9xxxxxxxx,
    // and I also saw 7xxxxxxxx. So let us a little bit conservative here and
    // set 200000000 to avoie test flakiness.
    REQUIRE(counter.enabled >= 200000000);
    REQUIRE(counter.running >= 0);
    REQUIRE(counter.running <= counter.enabled);
  #endif
  }
  