ll_prof: Terminate mmap file names on the first NUL char.

tools/ll_prof.py

 #!/usr/bin/env python
 #
 # Copyright 2010 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 613 matching lines @@
     if self.offset >= self.limit:
       return None, 0
     offset = self.offset
     header = PERF_EVENT_HEADER_DESC.Read(self.trace, self.offset)
     self.offset += header.size
     return header, offset
 
   def ReadMmap(self, header, offset):
     mmap_info = PERF_MMAP_EVENT_BODY_DESC.Read(self.trace,
                                                offset + self.header_size)
-    # Read null-padded filename.
+    # Read null-terminated filename.
     filename = self.trace[offset + self.header_size + ctypes.sizeof(mmap_info):
-                          offset + header.size].rstrip(chr(0))
-    mmap_info.filename = filename
+                          offset + header.size]
+    mmap_info.filename = filename[:filename.find(chr(0))]
     return mmap_info
 
   def ReadSample(self, header, offset):
     sample = self.sample_event_body_desc.Read(self.trace,
                                               offset + self.header_size)
     if not self.callchain_supported:
       return sample
     sample.ips = []
     offset += self.header_size + ctypes.sizeof(sample)
     for _ in xrange(sample.nr):
@@ skipping 285 matching lines @@
       print "%10d total ticks" % ticks
       print "%10d ticks not in symbols" % missed_ticks
       print "%10d unaccounted ticks" % really_missed_ticks
       print "%10d total symbols" % len([c for c in code_map.AllCode()])
       print "%10d used symbols" % len([c for c in code_map.UsedCode()])
       print "%9.2fs library processing time" % mmap_time
       print "%9.2fs tick processing time" % sample_time
 
   log_reader.Dispose()
   trace_reader.Dispose()