1 /* 2 * Copyright (c) 2017 Facebook, Inc. 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 <linux/perf_event.h> 18 #include <linux/version.h> 19 #include <unistd.h> 20 #include <string> 21 22 #include "BPF.h" 23 #include "catch.hpp" 24 25 TEST_CASE("test read perf event", "[bpf_perf_event]") { 26 // The basic bpf_perf_event_read is supported since Kernel 4.3. However in that 27 // version it only supported HARDWARE and RAW events. On the other hand, our 28 // tests running on Jenkins won't have available HARDWARE counters since they 29 // are running on VMs. The support of other types of events such as SOFTWARE are 30 // only added since Kernel 4.13, hence we can only run the test since that. 31 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0) 32 const std::string BPF_PROGRAM = R"( 33 BPF_PERF_ARRAY(cnt, NUM_CPUS); 34 BPF_HASH(val, int, u64, 1); 35 BPF_HASH(ret, int, int, 1); 36 BPF_HASH(counter, int, struct bpf_perf_event_value, 1); 37 38 int on_sys_getuid(void *ctx) { 39 int zero = 0; 40 41 u64 v = cnt.perf_read(CUR_CPU_IDENTIFIER); 42 if (((s64)v < 0) && ((s64)v > -256)) 43 return 0; 44 val.update(&zero, &v); 45 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) 46 u32 cpu = bpf_get_smp_processor_id(); 47 struct bpf_perf_event_value c = {0}; 48 int r = cnt.perf_counter_value(cpu, &c, sizeof(c)); 49 ret.update(&zero, &r); 50 counter.update(&zero, &c); 51 #endif 52 return 0; 53 } 54 )"; 55 56 ebpf::BPF bpf; 57 ebpf::StatusTuple res(0); 58 res = bpf.init( 59 BPF_PROGRAM, 60 {"-DNUM_CPUS=" + std::to_string(sysconf(_SC_NPROCESSORS_ONLN))}, {}); 61 REQUIRE(res.ok()); 62 res = 63 bpf.open_perf_event("cnt", PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK); 64 REQUIRE(res.ok()); 65 std::string getuid_fnname = bpf.get_syscall_fnname("getuid"); 66 res = bpf.attach_kprobe(getuid_fnname, "on_sys_getuid"); 67 REQUIRE(res.ok()); 68 REQUIRE(getuid() >= 0); 69 res = bpf.detach_kprobe(getuid_fnname); 70 REQUIRE(res.ok()); 71 res = bpf.close_perf_event("cnt"); 72 REQUIRE(res.ok()); 73 74 auto val = bpf.get_hash_table<int, uint64_t>("val"); 75 REQUIRE(val[0] >= 0); 76 #endif 77 78 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) 79 auto counter_table = 80 bpf.get_hash_table<int, struct bpf_perf_event_value>("counter"); 81 auto counter = counter_table[0]; 82 auto ret = bpf.get_hash_table<int, int>("ret"); 83 REQUIRE(ret[0] == 0); 84 REQUIRE(counter.counter >= 0); 85 REQUIRE(counter.enabled > 0); 86 REQUIRE(counter.running >= 0); 87 REQUIRE(counter.running <= counter.enabled); 88 #endif 89 } 90 91 TEST_CASE("test attach perf event", "[bpf_perf_event]") { 92 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0) 93 const std::string BPF_PROGRAM = R"( 94 BPF_HASH(pid, int, u64, 1); 95 BPF_HASH(ret, int, int, 1); 96 BPF_HASH(counter, int, struct bpf_perf_event_value, 1); 97 98 int on_event(void *ctx) { 99 int zero = 0; 100 101 u64 p = bpf_get_current_pid_tgid(); 102 pid.update(&zero, &p); 103 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) 104 struct bpf_perf_event_value c = {0}; 105 int r = bpf_perf_prog_read_value(ctx, &c, sizeof(c)); 106 ret.update(&zero, &r); 107 counter.update(&zero, &c); 108 #endif 109 return 0; 110 } 111 )"; 112 113 ebpf::BPF bpf; 114 ebpf::StatusTuple res(0); 115 res = bpf.init(BPF_PROGRAM); 116 REQUIRE(res.ok()); 117 res = bpf.attach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK, 118 "on_event", 0, 1000); 119 REQUIRE(res.ok()); 120 sleep(1); 121 res = bpf.detach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK); 122 REQUIRE(res.ok()); 123 124 auto pid = bpf.get_hash_table<int, uint64_t>("pid"); 125 REQUIRE(pid[0] >= 0); 126 #endif 127 128 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) 129 auto counter_table = 130 bpf.get_hash_table<int, struct bpf_perf_event_value>("counter"); 131 auto counter = counter_table[0]; 132 auto ret = bpf.get_hash_table<int, int>("ret"); 133 REQUIRE(ret[0] == 0); 134 REQUIRE(counter.counter >= 0); 135 // the program slept one second between perf_event attachment and detachment 136 // in the above, so the enabled counter should be 1000000000ns or 137 // more. But in reality, most of counters (if not all) are 9xxxxxxxx, 138 // and I also saw 7xxxxxxxx. So let us a little bit conservative here and 139 // set 200000000 to avoie test flakiness. 140 REQUIRE(counter.enabled >= 200000000); 141 REQUIRE(counter.running >= 0); 142 REQUIRE(counter.running <= counter.enabled); 143 #endif 144 } 145