Merge pull request iovisor#152 from iovisor/bblanco_dev

Add getitem api to BPF object to reference tables

examples/vfsreadlat.py

@@ -41,7 +41,6 @@ def usage():
 b = BPF(src_file = "vfsreadlat.c")
 b.attach_kprobe(event="vfs_read", fn_name="do_entry")
 b.attach_kretprobe(event="vfs_read", fn_name="do_return")
-dist = b.get_table("dist")
 dist_max = 64
 
 # header
@@ -69,7 +68,7 @@ def print_log2_hist(d, val_type):
  val_max = 0
  for i in range(1, dist_max + 1):
  try:
- val = dist[c_int(i)].value - last[i]
+ val = b["dist"][c_int(i)].value - last[i]
  if (val > 0):
  idx_max = i
  if (val > val_max):
@@ -84,10 +83,10 @@ def print_log2_hist(d, val_type):
  if (low == high):
  low -= 1
  try:
- val = dist[c_int(i)].value - last[i]
+ val = b["dist"][c_int(i)].value - last[i]
  print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
  stars_max, stars(val, val_max, stars_max)))
- last[i] = dist[c_int(i)].value
+ last[i] = b["dist"][c_int(i)].value
  except:
  break
 
@@ -105,6 +104,6 @@ def print_log2_hist(d, val_type):
  pass; do_exit = 1
 
  print
- print_log2_hist(dist, "usecs")
+ print_log2_hist(b["dist"], "usecs")
  if do_exit:
  exit()

src/python/bpf/__init__.py

@@ -223,6 +223,7 @@ def _find_file(filename):
  def __init__(self, src_file="", hdr_file="", text=None, debug=0):
  self.debug = debug
  self.funcs = {}
+ self.tables = {}
  if text:
  self.module = lib.bpf_module_create_c_from_string(text.encode("ascii"), self.debug)
  else:
@@ -297,7 +298,7 @@ def get_table(self, name, keytype=None, leaftype=None):
  map_id = lib.bpf_table_id(self.module, name.encode("ascii"))
  map_fd = lib.bpf_table_fd(self.module, name.encode("ascii"))
  if map_fd < 0:
- raise Exception("Failed to find BPF Table %s" % name)
+ raise KeyError
  if not keytype:
  key_desc = lib.bpf_table_key_desc(self.module, name.encode("ascii"))
  if not key_desc:
@@ -310,6 +311,23 @@ def get_table(self, name, keytype=None, leaftype=None):
  leaftype = BPF._decode_table_type(json.loads(leaf_desc.decode()))
  return BPF.Table(self, map_id, map_fd, keytype, leaftype)
 
+ def __getitem__(self, key):
+ if key not in self.tables:
+ self.tables[key] = self.get_table(key)
+ return self.tables[key]
+
+ def __setitem__(self, key, leaf):
+ self.tables[key] = leaf
+
+ def __len__(self):
+ return len(self.tables)
+
+ def __delitem__(self, key):
+ del self.tables[key]
+
+ def __iter__(self):
+ return self.tables.__iter__()
+
  @staticmethod
  def attach_raw_socket(fn, dev):
  if not isinstance(fn, BPF.Function):