Fixup objdump calling syntax and add docstrings

Use the full path invocation of objdump in both places.

Add a docstring for the variants of attach_retprobe.

Signed-off-by: Brenden Blanco <[email protected]>

src/python/bcc/__init__.py

@@ -725,7 +725,9 @@ def find_load_address(cls, path):
  return cls._lib_load_address_cache[path]
 
  # "LOAD off 0x0000000000000000 vaddr 0x0000000000400000 paddr 0x..."
- with os.popen("""/usr/bin/objdump -x %s | awk '$1 == "LOAD" && $3 ~ /^[0x]*$/ { print $5 }'""" % path) as f:
+ with os.popen("""/usr/bin/objdump -x %s | \
+ awk '$1 == "LOAD" && $3 ~ /^[0x]*$/ \
+ { print $5 }'""" % path) as f:
  data = f.read().rstrip()
  if not data:
  return None
@@ -741,7 +743,9 @@ def find_symbol(cls, path, sym):
  if sym in symbols:
  return symbols[sym]
 
- with os.popen("""objdump -tT %s | awk -v sym=%s '$NF == sym && $4 == ".text" { print $1; exit }'""" % (path, sym)) as f:
+ with os.popen("""/usr/bin/objdump -tT %s | \
+ awk -v sym=%s '$NF == sym && $4 == ".text" \
+ { print $1; exit }'""" % (path, sym)) as f:
  data = f.read().rstrip()
  if not data:
  return None
@@ -769,6 +773,21 @@ def _check_path_symbol(cls, name, sym, addr):
 
  def attach_uprobe(self, name="", sym="", addr=None,
  fn_name="", pid=-1, cpu=0, group_fd=-1):
+ """attach_uprobe(name="", sym="", addr=None, fn_name=""
+ pid=-1, cpu=0, group_fd=-1)
+
+ Run the bpf function denoted by fn_name every time the symbol sym in
+ the library or binary 'name' is encountered. The real address addr may
+ be supplied in place of sym. Optional parameters pid, cpu, and group_fd
+ can be used to filter the probe.
+
+ Libraries can be given in the name argument without the lib prefix, or
+ with the full path (/usr/lib/...). Binaries can be given only with the
+ full path (/bin/sh).
+
+ Example: BPF(text).attach_uprobe("c", "malloc")
+ BPF(text).attach_uprobe("/usr/bin/python", "main")
+ """
 
  (path, addr) = BPF._check_path_symbol(name, sym, addr)
 
@@ -786,6 +805,12 @@ def attach_uprobe(self, name="", sym="", addr=None,
 
  @classmethod
  def detach_uprobe(cls, name="", sym="", addr=None):
+ """detach_uprobe(name="", sym="", addr=None)
+
+ Stop running a bpf function that is attached to symbol 'sym' in library
+ or binary 'name'.
+ """
+
  (path, addr) = BPF._check_path_symbol(name, sym, addr)
  ev_name = "p_%s_0x%x" % (cls._probe_repl.sub("_", path), addr)
  if ev_name not in open_uprobes:
@@ -799,6 +824,13 @@ def detach_uprobe(cls, name="", sym="", addr=None):
 
  def attach_uretprobe(self, name="", sym="", addr=None,
  fn_name="", pid=-1, cpu=0, group_fd=-1):
+ """attach_uretprobe(name="", sym="", addr=None, fn_name=""
+ pid=-1, cpu=0, group_fd=-1)
+
+ Run the bpf function denoted by fn_name every time the symbol sym in
+ the library or binary 'name' finishes execution. See attach_uprobe for
+ meaning of additional parameters.
+ """
 
  (path, addr) = BPF._check_path_symbol(name, sym, addr)
 
@@ -816,6 +848,12 @@ def attach_uretprobe(self, name="", sym="", addr=None,
 
  @classmethod
  def detach_uretprobe(cls, name="", sym="", addr=None):
+ """detach_uretprobe(name="", sym="", addr=None)
+
+ Stop running a bpf function that is attached to symbol 'sym' in library
+ or binary 'name'.
+ """
+
  (path, addr) = BPF._check_path_symbol(name, sym, addr)
  ev_name = "r_%s_0x%x" % (cls._probe_repl.sub("_", path), addr)
  if ev_name not in open_uprobes: