#!/usr/bin/env python
description = """
Attach the debugger to a Python process (given by its pid) and
extract as much information about its internal state as possible
without any user interaction. The target process is frozen while
this script runs and resumes when it is finished."""
# A backtrace is saved in the directory $SAGE_CRASH_LOGS, which is
# $DOT_SAGE/crash_logs by default. Any backtraces older than
# $SAGE_CRASH_DAYS (default: 7 if SAGE_CRASH_LOGS unset, -1 if
# set) are automatically deleted, but with a negative value they are
# never deleted.
import sys
import os
import subprocess
import signal
import tempfile
import sysconfig
from argparse import ArgumentParser
from datetime import datetime
def pid_exists(pid):
"""
Return True if and only if there is a process with id pid running.
"""
try:
os.kill(pid, 0)
return True
except (OSError, ValueError):
return False
def gdb_commands(pid, color):
cmds = ''
cmds += 'set prompt (sage-gdb-prompt)\n'
cmds += 'set verbose off\n'
cmds += 'attach {0}\n'.format(pid)
cmds += 'python\n'
cmds += 'print("\\n")\n'
cmds += 'print("Stack backtrace")\n'
cmds += 'print("---------------")\n'
cmds += 'import sys; sys.stdout.flush()\n'
cmds += 'end\n'
cmds += 'bt full\n'
script = os.path.join(os.environ['SAGE_LOCAL'], 'bin', 'sage-CSI-helper.py')
with open(script, 'r') as f:
cmds += 'python\n'
cmds += 'color = {0}\n'.format(color)
cmds += f.read()
cmds += 'end\n'
cmds += 'detach inferior 1\n'
cmds += 'python print("Stack backtrace (newest frame = first)\\n")\n'
cmds += 'python print("--------------------------------------\\n")\n'
cmds += 'python import sys; sys.stdout.flush()\n'
cmds += 'quit\n'
return cmds
def run_gdb(pid, color):
"""
Execute gdb.
"""
PIPE = subprocess.PIPE
env = dict(os.environ)
libpython = os.path.join(env['SAGE_LOCAL'], 'lib',
sysconfig.get_config_var('INSTSONAME'))
if sys.platform == 'macosx':
env['DYLD_INSERT_LIBRARIES'] = libpython
else:
env['LD_PRELOAD'] = libpython
try:
cmd = subprocess.Popen('gdb', stdin=PIPE, stdout=PIPE,
stderr=PIPE, env=env)
except OSError:
return "Unable to start gdb (not installed?)"
stdout, stderr = cmd.communicate(gdb_commands(pid, color))
result = []
for line in stdout.splitlines():
if line.find('(sage-gdb-prompt)') >= 0:
continue
if line.startswith('Reading symbols from '):
continue
if line.startswith('Loaded symbols for '):
continue
result.append(line)
if stderr != "":
result.append(stderr)
return '\n'.join(result)
def mkdir_p(path):
try:
os.makedirs(path)
except OSError as e:
if os.path.isdir(path):
pass
else:
raise
def prune_old_logs(directory, days):
"""
Delete all files in ``directory`` that are older than a given
number of days.
"""
for filename in os.listdir(directory):
filename = os.path.join(directory, filename)
mtime = datetime.utcfromtimestamp(os.path.getmtime(filename))
age = datetime.utcnow() - mtime
if age.days >= days:
try:
os.unlink(filename)
except OSError:
pass
def save_backtrace(output):
try:
bt_dir = os.environ['SAGE_CRASH_LOGS']
# Don't delete all files in this directory, in case the user
# set SAGE_CRASH_LOGS to a stupic value.
bt_days = -1
except KeyError:
bt_dir = os.path.join(os.environ['DOT_SAGE'], 'crash_logs')
bt_days = 7
try:
bt_days = int(os.environ['SAGE_CRASH_DAYS'])
except KeyError:
pass
mkdir_p(bt_dir)
if bt_days >= 0:
prune_old_logs(bt_dir, bt_days)
f, filename = tempfile.mkstemp(dir=bt_dir, prefix='sage_crash_', suffix='.log')
os.write(f, output)
os.close(f)
return filename
if __name__ == '__main__':
parser = ArgumentParser(description=description)
parser.add_argument('-p', '--pid', dest='pid', action='store',
default=None, type=int,
help='the pid to attach to.')
parser.add_argument('-nc', '--no-color', dest='nocolor', action='store_true',
default=False,
help='turn off syntax-highlighting.')
parser.add_argument('-k', '--kill', dest='kill', action='store_true',
default=False,
help='kill after inspection is finished.')
args = parser.parse_args()
if args.pid is None:
parser.print_help()
sys.exit(0)
if not pid_exists(args.pid):
print 'There is no process with pid {0}.'.format(args.pid)
sys.exit(1)
print 'Attaching gdb to process id {0}.'.format(args.pid)
trace = run_gdb(args.pid, not args.nocolor)
print trace
fatalities = [
( 'Unable to start gdb',
'GDB is not installed.' ),
( 'Hangup detected on fd 0',
'Your system GDB is an old version that does not work with pipes'),
( 'error detected on stdin',
'Your system GDB does not have Python support'),
( 'ImportError: No module named',
'Your system GDB uses an incompatible version of Python') ]
fail = False
for key, msg in fatalities:
if key in trace:
print
print msg
fail = True
break
if fail:
print 'Install the gdb spkg (sage -f gdb) for enhanced tracebacks.'
else:
filename = save_backtrace(trace)
print 'Saved trace to {0}'.format(filename)
if args.kill:
os.kill(args.pid, signal.SIGKILL)
