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#!/usr/bin/env python
"""CaptureCmd - A generic tool for capturing information about the
invocations of another program.
Usage
--
1. Move the original tool to a safe known location.
2. Link CaptureCmd to the original tool's location.
3. Define CAPTURE_CMD_PROGRAM to the known location of the original
tool; this must be an absolute path.
4. Define CAPTURE_CMD_DIR to a directory to write invocation
information to.
"""
import hashlib
import os
import sys
import time
def saveCaptureData(prefix, dir, object):
string = repr(object) + '\n'
key = hashlib.sha1(string).hexdigest()
path = os.path.join(dir,
prefix + key)
if not os.path.exists(path):
f = open(path, 'wb')
f.write(string)
f.close()
return prefix + key
def main():
program = os.getenv('CAPTURE_CMD_PROGRAM')
dir = os.getenv('CAPTURE_CMD_DIR')
fallback = os.getenv('CAPTURE_CMD_FALLBACK')
if not program:
raise ValueError('CAPTURE_CMD_PROGRAM is not defined!')
if not dir:
raise ValueError('CAPTURE_CMD_DIR is not defined!')
# Make the output directory if it doesn't already exist.
if not os.path.exists(dir):
os.mkdir(dir, 0700)
# Get keys for various data.
env = os.environ.items()
env.sort()
envKey = saveCaptureData('env-', dir, env)
cwdKey = saveCaptureData('cwd-', dir, os.getcwd())
argvKey = saveCaptureData('argv-', dir, sys.argv)
entry = (time.time(), envKey, cwdKey, argvKey)
saveCaptureData('cmd-', dir, entry)
if fallback:
pid = os.fork()
if not pid:
os.execv(program, sys.argv)
os._exit(1)
else:
res = os.waitpid(pid, 0)
if not res:
os.execv(fallback, sys.argv)
os._exit(1)
os._exit(res)
else:
os.execv(program, sys.argv)
os._exit(1)
if __name__ == '__main__':
main()