llvm-project

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