Merge pull request iovisor#200 from iovisor/bblanco_dev

Improve coverage for kprobe event_re
sjtuhjh · Sep 10, 2015 · ed85df7 · ed85df7
2 parents 076e8ab + 7e71aef
commit ed85df7
Show file tree

Hide file tree

Showing 3 changed files with 28 additions and 10 deletions.
diff --git a/src/cc/libbpf.c b/src/cc/libbpf.c
@@ -239,7 +239,9 @@ int bpf_attach_kprobe(int progfd, const char *event,
   }
 
   if (write(kfd, event_desc, strlen(event_desc)) < 0) {
-    perror("write(kprobe_events)");
+    fprintf(stderr, "write of \"%s\" into kprobe_events failed: %s\n", event_desc, strerror(errno));
+    if (errno == EINVAL)
+      fprintf(stderr, "check dmesg output for possible cause\n");
     goto cleanup;
   }
 

diff --git a/src/python/bcc/__init__.py b/src/python/bcc/__init__.py
@@ -473,20 +473,26 @@ def _get_kprobe_functions(event_re):
         p = Popen(["awk", "$1 ~ /%s/ { print $1 }" % event_re,
             "%s/available_filter_functions" % TRACEFS], stdout=PIPE)
         lines = p.communicate()[0].decode().split()
-        return [line.rstrip() for line in lines if line != "\n"]
+        with open("%s/../kprobes/blacklist" % TRACEFS) as f:
+            blacklist = [line.split()[1] for line in f.readlines()]
+        return [line.rstrip() for line in lines if
+                (line != "\n" and line not in blacklist)]
 
     def attach_kprobe(self, event="", fn_name="", event_re="",
             pid=0, cpu=-1, group_fd=-1):
 
         # allow the caller to glob multiple functions together
         if event_re:
             for line in BPF._get_kprobe_functions(event_re):
-                self.attach_kprobe(event=line, fn_name=fn_name, pid=pid,
-                        cpu=cpu, group_fd=group_fd)
+                try:
+                    self.attach_kprobe(event=line, fn_name=fn_name, pid=pid,
+                            cpu=cpu, group_fd=group_fd)
+                except:
+                    pass
             return
 
         fn = self.load_func(fn_name, BPF.KPROBE)
-        ev_name = "p_" + event.replace("+", "_")
+        ev_name = "p_" + event.replace("+", "_").replace(".", "_")
         desc = "p:kprobes/%s %s" % (ev_name, event)
         res = lib.bpf_attach_kprobe(fn.fd, ev_name.encode("ascii"),
                 desc.encode("ascii"), pid, cpu, group_fd)
@@ -497,7 +503,7 @@ def attach_kprobe(self, event="", fn_name="", event_re="",
 
     @staticmethod
     def detach_kprobe(event):
-        ev_name = "p_" + event.replace("+", "_")
+        ev_name = "p_" + event.replace("+", "_").replace(".", "_")
         if ev_name not in open_kprobes:
             raise Exception("Kprobe %s is not attached" % event)
         os.close(open_kprobes[ev_name])
@@ -513,12 +519,15 @@ def attach_kretprobe(self, event="", fn_name="", event_re="",
         # allow the caller to glob multiple functions together
         if event_re:
             for line in BPF._get_kprobe_functions(event_re):
-                self.attach_kretprobe(event=line, fn_name=fn_name, pid=pid,
-                        cpu=cpu, group_fd=group_fd)
+                try:
+                    self.attach_kretprobe(event=line, fn_name=fn_name, pid=pid,
+                            cpu=cpu, group_fd=group_fd)
+                except:
+                    pass
             return
 
         fn = self.load_func(fn_name, BPF.KPROBE)
-        ev_name = "r_" + event.replace("+", "_")
+        ev_name = "r_" + event.replace("+", "_").replace(".", "_")
         desc = "r:kprobes/%s %s" % (ev_name, event)
         res = lib.bpf_attach_kprobe(fn.fd, ev_name.encode("ascii"),
                 desc.encode("ascii"), pid, cpu, group_fd)
@@ -529,7 +538,7 @@ def attach_kretprobe(self, event="", fn_name="", event_re="",
 
     @staticmethod
     def detach_kretprobe(event):
-        ev_name = "r_" + event.replace("+", "_")
+        ev_name = "r_" + event.replace("+", "_").replace(".", "_")
         if ev_name not in open_kprobes:
             raise Exception("Kretprobe %s is not attached" % event)
         os.close(open_kprobes[ev_name])

diff --git a/tests/cc/test_trace4.py b/tests/cc/test_trace4.py
@@ -30,5 +30,12 @@ def test_send1(self):
         k2 = self.b["stats"].Key(2)
         self.assertEqual(self.b["stats"][k1].val, self.b["stats"][k2].val + 1)
 
+class TestKprobeReplace(TestCase):
+    def setUp(self):
+        self.b = BPF(text="int empty(void *ctx) { return 0; }")
+
+    def test_periods(self):
+        self.b.attach_kprobe(event_re="^tcp_enter_cwr.*", fn_name="empty")
+
 if __name__ == "__main__":
     main()