simpletrace_stap.py (2467B)
1 # -*- coding: utf-8 -*- 2 3 """ 4 Generate .stp file that outputs simpletrace binary traces (DTrace with SystemTAP only). 5 """ 6 7 __author__ = "Stefan Hajnoczi <redhat.com>" 8 __copyright__ = "Copyright (C) 2014, Red Hat, Inc." 9 __license__ = "GPL version 2 or (at your option) any later version" 10 11 __maintainer__ = "Stefan Hajnoczi" 12 __email__ = "stefanha@redhat.com" 13 14 15 from tracetool import out 16 from tracetool.backend.dtrace import probeprefix 17 from tracetool.backend.simple import is_string 18 from tracetool.format.stap import stap_escape 19 20 def global_var_name(name): 21 return probeprefix().replace(".", "_") + "_" + name 22 23 def generate(events, backend, group): 24 out('/* This file is autogenerated by tracetool, do not edit. */', 25 '') 26 27 for event_id, e in enumerate(events): 28 if 'disable' in e.properties: 29 continue 30 31 out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?', 32 '{', 33 probeprefix=probeprefix(), 34 name=e.name) 35 36 # Calculate record size 37 sizes = ['24'] # sizeof(TraceRecord) 38 for type_, name in e.args: 39 name = stap_escape(name) 40 if is_string(type_): 41 out(' try {', 42 ' arg%(name)s_str = %(name)s ? user_string_n(%(name)s, 512) : "<null>"', 43 ' } catch {}', 44 ' arg%(name)s_len = strlen(arg%(name)s_str)', 45 name=name) 46 sizes.append('4 + arg%s_len' % name) 47 else: 48 sizes.append('8') 49 sizestr = ' + '.join(sizes) 50 51 # Generate format string and value pairs for record header and arguments 52 fields = [('8b', str(event_id)), 53 ('8b', 'gettimeofday_ns()'), 54 ('4b', sizestr), 55 ('4b', 'pid()')] 56 for type_, name in e.args: 57 name = stap_escape(name) 58 if is_string(type_): 59 fields.extend([('4b', 'arg%s_len' % name), 60 ('.*s', 'arg%s_len, arg%s_str' % (name, name))]) 61 else: 62 fields.append(('8b', name)) 63 64 # Emit the entire record in a single SystemTap printf() 65 fmt_str = '%'.join(fmt for fmt, _ in fields) 66 arg_str = ', '.join(arg for _, arg in fields) 67 out(' printf("%%8b%%%(fmt_str)s", 1, %(arg_str)s)', 68 fmt_str=fmt_str, arg_str=arg_str) 69 70 out('}') 71 72 out()