Clean libbpf interface arguments for tracing events

src/cc/api/BPF.cc

@@ -172,7 +172,7 @@ StatusTuple BPF::attach_kprobe(const std::string& kernel_func,
 
   void* res =
       bpf_attach_kprobe(probe_fd, attach_type, probe_event.c_str(), kernel_func.c_str(),
-                        pid, cpu, group_fd, cb, cb_cookie);
+                        cb, cb_cookie);
 
   if (!res) {
     TRY2(unload_func(probe_func));
@@ -208,7 +208,7 @@ StatusTuple BPF::attach_uprobe(const std::string& binary_path,
 
   void* res =
       bpf_attach_uprobe(probe_fd, attach_type, probe_event.c_str(), binary_path.c_str(),
-                        offset, pid, cpu, group_fd, cb, cb_cookie);
+                        offset, pid, cb, cb_cookie);
 
   if (!res) {
     TRY2(unload_func(probe_func));
@@ -275,8 +275,8 @@ StatusTuple BPF::attach_tracepoint(const std::string& tracepoint,
   TRY2(load_func(probe_func, BPF_PROG_TYPE_TRACEPOINT, probe_fd));
 
   void* res =
-      bpf_attach_tracepoint(probe_fd, tp_category.c_str(), tp_name.c_str(), pid,
-                            cpu, group_fd, cb, cb_cookie);
+      bpf_attach_tracepoint(probe_fd, tp_category.c_str(), tp_name.c_str(), cb,
+                            cb_cookie);
 
   if (!res) {
     TRY2(unload_func(probe_func));

src/cc/libbpf.c

@@ -529,8 +529,8 @@ int bpf_attach_socket(int sock, int prog) {
 }
 
 static int bpf_attach_tracing_event(int progfd, const char *event_path,
-    struct perf_reader *reader, int pid, int cpu, int group_fd) {
-  int efd, pfd;
+                                    struct perf_reader *reader, int pid) {
+  int efd, pfd, cpu = 0;
   ssize_t bytes;
   char buf[256];
   struct perf_event_attr attr = {};
@@ -555,7 +555,15 @@ static int bpf_attach_tracing_event(int progfd, const char *event_path,
   attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN;
   attr.sample_period = 1;
   attr.wakeup_events = 1;
-  pfd = syscall(__NR_perf_event_open, &attr, pid, cpu, group_fd, PERF_FLAG_FD_CLOEXEC);
+  // PID filter is only possible for uprobe events.
+  if (pid < 0)
+    pid = -1;
+  // perf_event_open API doesn't allow both pid and cpu to be -1.
+  // So only set it to -1 when PID is not -1.
+  // Tracing events do not do CPU filtering in any cases.
+  if (pid != -1)
+    cpu = -1;
+  pfd = syscall(__NR_perf_event_open, &attr, pid, cpu, -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
   if (pfd < 0) {
     fprintf(stderr, "perf_event_open(%s/id): %s\n", event_path, strerror(errno));
     return -1;
@@ -577,9 +585,8 @@ static int bpf_attach_tracing_event(int progfd, const char *event_path,
   return 0;
 }
 
-void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type, const char *ev_name,
-                        const char *fn_name,
-                        pid_t pid, int cpu, int group_fd,
+void *bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type,
+                        const char *ev_name, const char *fn_name,
                         perf_reader_cb cb, void *cb_cookie)
 {
   int kfd;
@@ -611,7 +618,7 @@ void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type, con
   close(kfd);
 
   snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s", event_type, event_alias);
-  if (bpf_attach_tracing_event(progfd, buf, reader, pid, cpu, group_fd) < 0)
+  if (bpf_attach_tracing_event(progfd, buf, reader, -1 /* PID */) < 0)
     goto error;
 
   return reader;
@@ -683,10 +690,10 @@ static void exit_mount_ns(int fd) {
     perror("setns");
 }
 
-void * bpf_attach_uprobe(int progfd, enum bpf_probe_attach_type attach_type, const char *ev_name,
-                        const char *binary_path, uint64_t offset,
-                        pid_t pid, int cpu, int group_fd,
-                        perf_reader_cb cb, void *cb_cookie)
+void *bpf_attach_uprobe(int progfd, enum bpf_probe_attach_type attach_type,
+                        const char *ev_name, const char *binary_path,
+                        uint64_t offset, pid_t pid, perf_reader_cb cb,
+                        void *cb_cookie)
 {
   char buf[PATH_MAX];
   char event_alias[PATH_MAX];
@@ -728,7 +735,7 @@ void * bpf_attach_uprobe(int progfd, enum bpf_probe_attach_type attach_type, con
   ns_fd = -1;
 
   snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s", event_type, event_alias);
-  if (bpf_attach_tracing_event(progfd, buf, reader, pid, cpu, group_fd) < 0)
+  if (bpf_attach_tracing_event(progfd, buf, reader, pid) < 0)
     goto error;
 
   return reader;
@@ -782,9 +789,9 @@ int bpf_detach_uprobe(const char *ev_name)
 }
 
 
-void * bpf_attach_tracepoint(int progfd, const char *tp_category,
-                             const char *tp_name, int pid, int cpu,
-                             int group_fd, perf_reader_cb cb, void *cb_cookie) {
+void *bpf_attach_tracepoint(int progfd, const char *tp_category,
+                            const char *tp_name, perf_reader_cb cb,
+                            void *cb_cookie) {
   char buf[256];
   struct perf_reader *reader = NULL;
 
@@ -794,7 +801,7 @@ void * bpf_attach_tracepoint(int progfd, const char *tp_category,
 
   snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/%s",
            tp_category, tp_name);
-  if (bpf_attach_tracing_event(progfd, buf, reader, pid, cpu, group_fd) < 0)
+  if (bpf_attach_tracing_event(progfd, buf, reader, -1 /* PID */) < 0)
     goto error;
 
   return reader;

src/cc/libbpf.h

@@ -70,23 +70,22 @@ typedef void (*perf_reader_cb)(void *cb_cookie, int pid, uint64_t callchain_num,
 typedef void (*perf_reader_raw_cb)(void *cb_cookie, void *raw, int raw_size);
 typedef void (*perf_reader_lost_cb)(uint64_t lost);
 
-void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type,
+void *bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type,
                         const char *ev_name, const char *fn_name,
-                        pid_t pid, int cpu, int group_fd,
                         perf_reader_cb cb, void *cb_cookie);
 
 int bpf_detach_kprobe(const char *ev_name);
 
-void * bpf_attach_uprobe(int progfd, enum bpf_probe_attach_type attach_type,
-                        const char *ev_name, const char *binary_path, uint64_t offset,
-                        pid_t pid, int cpu, int group_fd,
-                        perf_reader_cb cb, void *cb_cookie);
+void *bpf_attach_uprobe(int progfd, enum bpf_probe_attach_type attach_type,
+                        const char *ev_name, const char *binary_path,
+                        uint64_t offset, pid_t pid, perf_reader_cb cb,
+                        void *cb_cookie);
 
 int bpf_detach_uprobe(const char *ev_name);
 
-void * bpf_attach_tracepoint(int progfd, const char *tp_category,
-                             const char *tp_name, int pid, int cpu,
-                             int group_fd, perf_reader_cb cb, void *cb_cookie);
+void *bpf_attach_tracepoint(int progfd, const char *tp_category,
+                            const char *tp_name, perf_reader_cb cb,
+                            void *cb_cookie);
 int bpf_detach_tracepoint(const char *tp_category, const char *tp_name);
 
 void * bpf_open_perf_buffer(perf_reader_raw_cb raw_cb,

src/lua/bcc/bpf.lua

@@ -189,9 +189,7 @@ function Bpf:attach_uprobe(args)
   local retprobe = args.retprobe and 1 or 0
 
   local res = libbcc.bpf_attach_uprobe(fn.fd, retprobe, ev_name, path, addr,
-    args.pid or -1,
-    args.cpu or 0,
-    args.group_fd or -1, nil, nil) -- TODO; reader callback
+    args.pid or -1, nil, nil) -- TODO; reader callback
 
   assert(res ~= nil, "failed to attach BPF to uprobe")
   self:probe_store("uprobe", ev_name, res)
@@ -209,9 +207,7 @@ function Bpf:attach_kprobe(args)
   local retprobe = args.retprobe and 1 or 0
 
   local res = libbcc.bpf_attach_kprobe(fn.fd, retprobe, ev_name, event,
-    args.pid or -1,
-    args.cpu or 0,
-    args.group_fd or -1, nil, nil) -- TODO; reader callback
+    nil, nil) -- TODO; reader callback
 
   assert(res ~= nil, "failed to attach BPF to kprobe")
   self:probe_store("kprobe", ev_name, res)

src/lua/bcc/libbcc.lua

@@ -43,16 +43,14 @@ typedef void (*perf_reader_cb)(void *cb_cookie, int pid, uint64_t callchain_num,
 typedef void (*perf_reader_raw_cb)(void *cb_cookie, void *raw, int raw_size);
 typedef void (*perf_reader_lost_cb)(uint64_t lost);
 
-void * bpf_attach_kprobe(int progfd, int attach_type, const char *ev_name,
-                        const char *fn_name,
-                        int pid, int cpu, int group_fd,
-                        perf_reader_cb cb, void *cb_cookie);
+void *bpf_attach_kprobe(int progfd, int attach_type, const char *ev_name,
+                        const char *fn_name, perf_reader_cb cb,
+                        void *cb_cookie);
 
 int bpf_detach_kprobe(const char *ev_name);
 
-void * bpf_attach_uprobe(int progfd, int attach_type, const char *ev_name,
-                        const char *binary_path, uint64_t offset,
-                        int pid, int cpu, int group_fd,
+void *bpf_attach_uprobe(int progfd, int attach_type, const char *ev_name,
+                        const char *binary_path, uint64_t offset, int pid,
                         perf_reader_cb cb, void *cb_cookie);
 
 int bpf_detach_uprobe(const char *ev_name);

src/python/bcc/__init__.py

@@ -519,8 +519,8 @@ class BPF(object):
         fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = "p_" + event.replace("+", "_").replace(".", "_")
         res = lib.bpf_attach_kprobe(fn.fd, 0, ev_name.encode("ascii"),
-                event.encode("ascii"), pid, cpu, group_fd,
-                self._reader_cb_impl, ct.cast(id(self), ct.py_object))
+                event.encode("ascii"), self._reader_cb_impl,
+                ct.cast(id(self), ct.py_object))
         res = ct.cast(res, ct.c_void_p)
         if not res:
             raise Exception("Failed to attach BPF to kprobe")
@@ -556,8 +556,8 @@ class BPF(object):
         fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = "r_" + event.replace("+", "_").replace(".", "_")
         res = lib.bpf_attach_kprobe(fn.fd, 1, ev_name.encode("ascii"),
-                event.encode("ascii"), pid, cpu, group_fd,
-                self._reader_cb_impl, ct.cast(id(self), ct.py_object))
+                event.encode("ascii"), self._reader_cb_impl,
+                ct.cast(id(self), ct.py_object))
         res = ct.cast(res, ct.c_void_p)
         if not res:
             raise Exception("Failed to attach BPF to kprobe")
@@ -680,8 +680,8 @@ class BPF(object):
         fn = self.load_func(fn_name, BPF.TRACEPOINT)
         (tp_category, tp_name) = tp.split(':')
         res = lib.bpf_attach_tracepoint(fn.fd, tp_category.encode("ascii"),
-                tp_name.encode("ascii"), pid, cpu, group_fd,
-                self._reader_cb_impl, ct.cast(id(self), ct.py_object))
+                tp_name.encode("ascii"), self._reader_cb_impl,
+                ct.cast(id(self), ct.py_object))
         res = ct.cast(res, ct.c_void_p)
         if not res:
             raise Exception("Failed to attach BPF to tracepoint")
@@ -833,8 +833,8 @@ class BPF(object):
         fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = self._get_uprobe_evname("p", path, addr, pid)
         res = lib.bpf_attach_uprobe(fn.fd, 0, ev_name.encode("ascii"),
-                path.encode("ascii"), addr, pid, cpu, group_fd,
-                self._reader_cb_impl, ct.cast(id(self), ct.py_object))
+                path.encode("ascii"), addr, pid, self._reader_cb_impl,
+                ct.cast(id(self), ct.py_object))
         res = ct.cast(res, ct.c_void_p)
         if not res:
             raise Exception("Failed to attach BPF to uprobe")
@@ -883,8 +883,8 @@ class BPF(object):
         fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = self._get_uprobe_evname("r", path, addr, pid)
         res = lib.bpf_attach_uprobe(fn.fd, 1, ev_name.encode("ascii"),
-                path.encode("ascii"), addr, pid, cpu, group_fd,
-                self._reader_cb_impl, ct.cast(id(self), ct.py_object))
+                path.encode("ascii"), addr, pid, self._reader_cb_impl,
+                ct.cast(id(self), ct.py_object))
         res = ct.cast(res, ct.c_void_p)
         if not res:
             raise Exception("Failed to attach BPF to uprobe")

src/python/bcc/libbcc.py

@@ -90,18 +90,18 @@ _CB_TYPE = ct.CFUNCTYPE(None, ct.py_object, ct.c_int,
         ct.c_ulonglong, ct.POINTER(ct.c_ulonglong))
 _RAW_CB_TYPE = ct.CFUNCTYPE(None, ct.py_object, ct.c_void_p, ct.c_int)
 _LOST_CB_TYPE = ct.CFUNCTYPE(None, ct.c_ulonglong)
-lib.bpf_attach_kprobe.argtypes = [ct.c_int, ct.c_int, ct.c_char_p, ct.c_char_p, ct.c_int,
-        ct.c_int, ct.c_int, _CB_TYPE, ct.py_object]
+lib.bpf_attach_kprobe.argtypes = [ct.c_int, ct.c_int, ct.c_char_p, ct.c_char_p,
+        _CB_TYPE, ct.py_object]
 lib.bpf_detach_kprobe.restype = ct.c_int
 lib.bpf_detach_kprobe.argtypes = [ct.c_char_p]
 lib.bpf_attach_uprobe.restype = ct.c_void_p
 lib.bpf_attach_uprobe.argtypes = [ct.c_int, ct.c_int, ct.c_char_p, ct.c_char_p,
-        ct.c_ulonglong, ct.c_int, ct.c_int, ct.c_int, _CB_TYPE, ct.py_object]
+        ct.c_ulonglong, ct.c_int, _CB_TYPE, ct.py_object]
 lib.bpf_detach_uprobe.restype = ct.c_int
 lib.bpf_detach_uprobe.argtypes = [ct.c_char_p]
 lib.bpf_attach_tracepoint.restype = ct.c_void_p
-lib.bpf_attach_tracepoint.argtypes = [ct.c_int, ct.c_char_p, ct.c_char_p, ct.c_int,
-        ct.c_int, ct.c_int, _CB_TYPE, ct.py_object]
+lib.bpf_attach_tracepoint.argtypes = [ct.c_int, ct.c_char_p, ct.c_char_p,
+        _CB_TYPE, ct.py_object]
 lib.bpf_detach_tracepoint.restype = ct.c_int
 lib.bpf_detach_tracepoint.argtypes = [ct.c_char_p, ct.c_char_p]
 lib.bpf_open_perf_buffer.restype = ct.c_void_p