C++ interface for attaching to perf event with raw perf_event_attr ar…

…gument

src/cc/api/BPF.cc

@@ -15,6 +15,7 @@
  */
 
 #include <linux/bpf.h>
+#include <linux/perf_event.h>
 #include <unistd.h>
 #include <cstdio>
 #include <cstring>
@@ -292,12 +293,13 @@ StatusTuple BPF::attach_perf_event(uint32_t ev_type, uint32_t ev_config,
  int probe_fd;
  TRY2(load_func(probe_func, BPF_PROG_TYPE_PERF_EVENT, probe_fd));
 
- auto fds = new std::map<int, int>();
  std::vector<int> cpus;
  if (cpu >= 0)
  cpus.push_back(cpu);
  else
  cpus = get_online_cpus();
+ auto fds = new std::vector<std::pair<int, int>>();
+ fds->reserve(cpus.size());
  for (int i : cpus) {
  int fd = bpf_attach_perf_event(probe_fd, ev_type, ev_config, sample_period,
  sample_freq, pid, i, group_fd);
@@ -309,7 +311,7 @@ StatusTuple BPF::attach_perf_event(uint32_t ev_type, uint32_t ev_config,
  return StatusTuple(-1, "Failed to attach perf event type %d config %d",
  ev_type, ev_config);
  }
- fds->emplace(i, fd);
+ fds->emplace_back(i, fd);
  }
 
  open_probe_t p = {};
@@ -319,6 +321,46 @@ StatusTuple BPF::attach_perf_event(uint32_t ev_type, uint32_t ev_config,
  return StatusTuple(0);
 }
 
+StatusTuple BPF::attach_perf_event_raw(void* perf_event_attr,
+ const std::string& probe_func,
+ pid_t pid, int cpu, int group_fd) {
+ auto attr = static_cast<struct perf_event_attr*>(perf_event_attr);
+ auto ev_pair = std::make_pair(attr->type, attr->config);
+ if (perf_events_.find(ev_pair) != perf_events_.end())
+ return StatusTuple(-1, "Perf event type %d config %d already attached",
+ attr->type, attr->config);
+
+ int probe_fd;
+ TRY2(load_func(probe_func, BPF_PROG_TYPE_PERF_EVENT, probe_fd));
+
+ std::vector<int> cpus;
+ if (cpu >= 0)
+ cpus.push_back(cpu);
+ else
+ cpus = get_online_cpus();
+ auto fds = new std::vector<std::pair<int, int>>();
+ fds->reserve(cpus.size());
+ for (int i : cpus) {
+ int fd = bpf_attach_perf_event_raw(probe_fd, attr, pid, i, group_fd);
+ if (fd < 0) {
+ for (const auto& it : *fds)
+ close(it.second);
+ delete fds;
+ TRY2(unload_func(probe_func));
+ return StatusTuple(-1, "Failed to attach perf event type %d config %d",
+ attr->type, attr->config);
+ }
+ fds->emplace_back(i, fd);
+ }
+
+ open_probe_t p = {};
+ p.func = probe_func;
+ p.per_cpu_fd = fds;
+ perf_events_[ev_pair] = std::move(p);
+ return StatusTuple(0);
+
+}
+
 StatusTuple BPF::detach_kprobe(const std::string& kernel_func,
  bpf_probe_attach_type attach_type) {
  std::string event = get_kprobe_event(kernel_func, attach_type);
@@ -394,6 +436,11 @@ StatusTuple BPF::detach_perf_event(uint32_t ev_type, uint32_t ev_config) {
  return StatusTuple(0);
 }
 
+StatusTuple BPF::detach_perf_event_raw(void* perf_event_attr) {
+ auto attr = static_cast<struct perf_event_attr*>(perf_event_attr);
+ return detach_perf_event(attr->type, attr->config);
+}
+
 StatusTuple BPF::open_perf_event(const std::string& name, uint32_t type,
  uint64_t config) {
  if (perf_event_arrays_.find(name) == perf_event_arrays_.end()) {

src/cc/api/BPF.h

@@ -36,7 +36,7 @@ namespace ebpf {
 struct open_probe_t {
  int perf_event_fd;
  std::string func;
- std::map<int, int>* per_cpu_fd;
+ std::vector<std::pair<int, int>>* per_cpu_fd;
 };
 
 class USDT;
@@ -84,7 +84,12 @@ class BPF {
  uint64_t sample_period, uint64_t sample_freq,
  pid_t pid = -1, int cpu = -1,
  int group_fd = -1);
+ StatusTuple attach_perf_event_raw(void* perf_event_attr,
+ const std::string& probe_func,
+ pid_t pid = -1, int cpu = -1,
+ int group_fd = -1);
  StatusTuple detach_perf_event(uint32_t ev_type, uint32_t ev_config);
+ StatusTuple detach_perf_event_raw(void* perf_event_attr);
 
  BPFTable get_table(const std::string& name) {
  TableStorage::iterator it;