Merge pull request #1765 from palmtenor/extraflag

Add extra_flag option to bpf_attach_perf_event_raw

src/cc/api/BPF.cc

@@ -324,7 +324,8 @@ StatusTuple BPF::attach_perf_event(uint32_t ev_type, uint32_t ev_config,
 
 StatusTuple BPF::attach_perf_event_raw(void* perf_event_attr,
                                        const std::string& probe_func, pid_t pid,
-                                       int cpu, int group_fd) {
+                                       int cpu, int group_fd,
+                                       unsigned long extra_flags) {
   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())
@@ -342,7 +343,8 @@ StatusTuple BPF::attach_perf_event_raw(void* perf_event_attr,
   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);
+    int fd = bpf_attach_perf_event_raw(probe_fd, attr, pid, i, group_fd,
+                                       extra_flags);
     if (fd < 0) {
       for (const auto& it : *fds)
         close(it.second);

src/cc/api/BPF.h

@@ -88,7 +88,8 @@ class BPF {
   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);
+                                    int group_fd = -1,
+                                    unsigned long extra_flags = 0);
   StatusTuple detach_perf_event(uint32_t ev_type, uint32_t ev_config);
   StatusTuple detach_perf_event_raw(void* perf_event_attr);
   std::string get_syscall_fnname(const std::string& name);

src/cc/libbpf.c

@@ -1305,9 +1305,9 @@ cleanup:
 }
 
 int bpf_attach_perf_event_raw(int progfd, void *perf_event_attr, pid_t pid,
-                              int cpu, int group_fd) {
+                              int cpu, int group_fd, unsigned long extra_flags) {
   int fd = syscall(__NR_perf_event_open, perf_event_attr, pid, cpu, group_fd,
-                   PERF_FLAG_FD_CLOEXEC);
+                   PERF_FLAG_FD_CLOEXEC | extra_flags);
   if (fd < 0) {
     perror("perf_event_open failed");
     return -1;
@@ -1351,7 +1351,7 @@ int bpf_attach_perf_event(int progfd, uint32_t ev_type, uint32_t ev_config,
     attr.sample_period = sample_period;
   }
 
-  return bpf_attach_perf_event_raw(progfd, &attr, pid, cpu, group_fd);
+  return bpf_attach_perf_event_raw(progfd, &attr, pid, cpu, group_fd, 0);
 }
 
 int bpf_close_perf_event_fd(int fd) {

src/cc/libbpf.h

@@ -93,7 +93,7 @@ int bpf_attach_xdp(const char *dev_name, int progfd, uint32_t flags);
 // attach a prog expressed by progfd to run on a specific perf event. The perf
 // event will be created using the perf_event_attr pointer provided.
 int bpf_attach_perf_event_raw(int progfd, void *perf_event_attr, pid_t pid,
-                              int cpu, int group_fd);
+                              int cpu, int group_fd, unsigned long extra_flags);
 // attach a prog expressed by progfd to run on a specific perf event, with
 // certain sample period or sample frequency
 int bpf_attach_perf_event(int progfd, uint32_t ev_type, uint32_t ev_config,