+#! /usr/bin/python3
+
+# Copyright (C) - 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
+#
+# This library is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation; version 2.1 of the License.
+#
+# This library is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+# for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this library; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+import sys
+import bisect
+import subprocess
+import re
+
+def addr2line(executable, addr):
+ """
+ Uses binutils' addr2line to get function containing a given address
+ """
+ cmd =['addr2line']
+
+ cmd += ['-e', executable]
+
+ # Print function names
+ cmd += ['--functions']
+
+ # Expand inlined functions
+ cmd += ['--addresses', addr]
+
+ addr2line_output = subprocess.getoutput(' '.join(cmd))
+
+ # Omit the last 2 lines as the caller of main can not be determine
+ fcts = [addr2line_output.split()[-2]]
+
+ fcts = [ f for f in fcts if '??' not in f]
+
+ return fcts
+
+def extract_user_func_names(executable, raw_callstack):
+ """
+ Given a callstack from the Babeltrace CLI output, returns a set
+ containing the name of the functions. This assumes that the binary have
+ not changed since the execution.
+ """
+ recorded_callstack = set()
+
+ # Remove commas and split on spaces
+ for index, addr in enumerate(raw_callstack.replace(',', '').split(' ')):
+ # Consider only the elements starting with '0x' which are the
+ # addresses recorded in the callstack
+ if '0x' in addr[:2]:
+ funcs = addr2line(executable, addr)
+ recorded_callstack.update(funcs)
+
+ return recorded_callstack
+
+def extract_kernel_func_names(raw_callstack):
+ """
+ Given a callstack from the Babeltrace CLI output, returns a set
+ containing the name of the functions.
+ Uses the /proc/kallsyms procfile to find the symbol associated with an
+ address. This function should only be used if the user is root or has
+ access to /proc/kallsyms.
+ """
+ recorded_callstack = set()
+ syms=[]
+ addresses=[]
+ # We read kallsyms file and save the output
+ with open('/proc/kallsyms') as kallsyms_f:
+ for line in kallsyms_f:
+ line_tokens = line.split()
+ addr = line_tokens[0]
+ symbol = line_tokens[2]
+ addresses.append(int(addr, 16))
+ syms.append({'addr':int(addr, 16), 'symbol':symbol})
+
+ # Save the address and symbol in a sorted list of tupple
+ syms = sorted(syms, key=lambda k:k['addr'])
+ # We save the list of addresses in a seperate sorted list to easily bisect
+ # the closer address of a symbol.
+ addresses = sorted(addresses)
+
+ # Remove commas and split on spaces
+ for addr in raw_callstack.replace(',', '').split(' '):
+ if '0x' in addr[:2]:
+ # Search the location of the address in the addresses list and
+ # deference this location in the syms list to add the associated
+ # symbol.
+ loc = bisect.bisect(addresses, int(addr, 16))
+ recorded_callstack.add(syms[loc-1]['symbol'])
+
+ return recorded_callstack
+
+# Regex capturing the callstack_user and callstack_kernel context
+user_cs_rexp='.*callstack_user\ \=\ \[(.*)\]\ .*\}, \{.*\}'
+kernel_cs_rexp='.*callstack_kernel\ \=\ \[(.*)\]\ .*\}, \{.*\}'
+
+def main():
+ """
+ Reads a line from stdin and expect it to be a wellformed Babeltrace CLI
+ output containing containing a callstack context of the domain passed
+ as argument.
+ """
+ expected_callstack = set()
+ recorded_callstack = set()
+ cs_type=None
+
+ if len(sys.argv) <= 2:
+ print(sys.argv)
+ raise ValueError('USAGE: ./{} (--kernel|--user EXE) FUNC-NAMES'.format(sys.argv[0]))
+
+ # If the `--user` option is passed, save the next argument as the path
+ # to the executable
+ argc=1
+ executable=None
+ if sys.argv[argc] in '--kernel':
+ rexp = kernel_cs_rexp
+ cs_type='kernel'
+ elif sys.argv[argc] in '--user':
+ rexp = user_cs_rexp
+ cs_type='user'
+ argc+=1
+ executable = sys.argv[argc]
+ else:
+ raise Exception('Unknown domain')
+
+ argc+=1
+
+ # Extract the function names that are expected to be found call stack of
+ # the current events
+ for func in sys.argv[argc:]:
+ expected_callstack.add(func)
+
+ # Read the tested line for STDIN
+ event_line = None
+ for line in sys.stdin:
+ event_line = line
+ break
+
+ # Extract the userspace callstack context of the event
+ m = re.match(rexp, event_line)
+
+ # If there is no match, exit with error
+ if m is None:
+ raise re.error('Callstack not found in event line')
+ else:
+ raw_callstack = str(m.group(1))
+ if cs_type in 'user':
+ recorded_callstack=extract_user_func_names(executable, raw_callstack)
+ elif cs_type in 'kernel':
+ recorded_callstack=extract_kernel_func_names(raw_callstack)
+ else:
+ raise Exception('Unknown domain')
+
+ # Verify that all expected function are present in the callstack
+ for e in expected_callstack:
+ if e not in recorded_callstack:
+ raise Exception('Expected function name not found in recorded callstack')
+
+ sys.exit(0)
+
+if __name__ == '__main__':
+ main()
projects / lttng-tools.git / commitdiff
