548 lines
16 KiB
Python
548 lines
16 KiB
Python
"""
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Miscellaneous utility functions, wrappers around some subprocess procedures.
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"""
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import importlib
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import inspect
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import os
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import subprocess
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import sys
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import fcntl
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import resource
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from core import logger
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def closeonexec(fd):
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"""
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Close on execution of a shell process.
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:param fd: file descriptor to close
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:return: nothing
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"""
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fdflags = fcntl.fcntl(fd, fcntl.F_GETFD)
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fcntl.fcntl(fd, fcntl.F_SETFD, fdflags | fcntl.FD_CLOEXEC)
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def check_executables(executables):
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"""
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Check executables, verify they exist and are executable.
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:param list[str] executables: executable to check
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:return: nothing
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:raises EnvironmentError: when an executable doesn't exist or is not executable
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"""
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for executable in executables:
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if not is_exe(executable):
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raise EnvironmentError("executable not found: %s" % executable)
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def is_exe(file_path):
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"""
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Check if a given file path exists and is an executable file.
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:param str file_path: file path to check
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:return: True if the file is considered and executable file, False otherwise
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:rtype: bool
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"""
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return os.path.isfile(file_path) and os.access(file_path, os.X_OK)
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def which(program):
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"""
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From: http://stackoverflow.com/questions/377017/test-if-executable-exists-in-python
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:param str program: program to check for
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:return: path if it exists, none otherwise
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"""
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fpath, fname = os.path.split(program)
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if fpath:
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if is_exe(program):
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return program
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else:
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for path in os.environ["PATH"].split(os.pathsep):
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path = path.strip("\"")
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exe_file = os.path.join(path, program)
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if is_exe(exe_file):
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return exe_file
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return None
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def ensurepath(pathlist):
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"""
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Checks a list of paths are contained within the environment path, if not add it to the path.
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:param list[str] pathlist: list of paths to check
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:return: nothing
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"""
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searchpath = os.environ["PATH"].split(":")
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for p in set(pathlist):
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if p not in searchpath:
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os.environ["PATH"] += ":" + p
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def maketuple(obj):
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"""
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Create a tuple from an object, or return the object itself.
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:param obj: object to convert to a tuple
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:return: converted tuple or the object itself
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:rtype: tuple
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"""
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if hasattr(obj, "__iter__"):
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return tuple(obj)
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else:
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return obj,
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def maketuplefromstr(s, value_type):
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"""
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Create a tuple from a string.
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:param str s: string to convert to a tuple
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:param value_type: type of values to be contained within tuple
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:return: tuple from string
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:rtype: tuple
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"""
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# remove tuple braces and strip commands and space from all values in the tuple string
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values = [x.strip("' ") for x in s.strip("(), ").split(",")]
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return tuple(value_type(i) for i in values)
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def mutecall(*args, **kwargs):
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"""
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Run a muted call command.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: command result
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:rtype: int
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"""
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kwargs["stdout"] = open(os.devnull, "w")
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kwargs["stderr"] = subprocess.STDOUT
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return subprocess.call(*args, **kwargs)
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def check_alloutput(cmd, **kwargs):
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"""
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Convenience wrapper to run subprocess.check_output and include stderr as well.
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:param list[str] cmd: command arguments to run
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:param dict kwargs: option for running subprocess.check_output, beyond setting stderr to stdout
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:return: combined stdout and stderr
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:raises subprocess.CalledProcessError: when a non-zero exit status is encountered
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"""
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kwargs["stderr"] = subprocess.STDOUT
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return subprocess.check_output(cmd, **kwargs)
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def mutecheck_call(*args, **kwargs):
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"""
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Run a muted check call command.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: command result
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:rtype: int
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"""
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kwargs["stdout"] = open(os.devnull, "w")
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kwargs["stderr"] = subprocess.STDOUT
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return subprocess.check_call(*args, **kwargs)
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def spawn(*args, **kwargs):
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"""
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Wrapper for running a spawn command and returning the process id.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: process id of the command
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:rtype: int
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"""
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return subprocess.Popen(*args, **kwargs).pid
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def mutespawn(*args, **kwargs):
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"""
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Wrapper for running a muted spawned command.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: process id of the command
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:rtype: int
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"""
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kwargs["stdout"] = open(os.devnull, "w")
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kwargs["stderr"] = subprocess.STDOUT
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return subprocess.Popen(*args, **kwargs).pid
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def detachinit():
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"""
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Fork a child process and exit.
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:return: nothing
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"""
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if os.fork():
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# parent exits
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os._exit(0)
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os.setsid()
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def detach(*args, **kwargs):
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"""
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Run a detached process by forking it.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: process id of the command
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:rtype: int
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"""
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kwargs["preexec_fn"] = detachinit
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return subprocess.Popen(*args, **kwargs).pid
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def mutedetach(*args, **kwargs):
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"""
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Run a muted detached process by forking it.
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:param list args: arguments for the command
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:param dict kwargs: keyword arguments for the command
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:return: process id of the command
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:rtype: int
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"""
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kwargs["preexec_fn"] = detachinit
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kwargs["stdout"] = open(os.devnull, "w")
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kwargs["stderr"] = subprocess.STDOUT
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return subprocess.Popen(*args, **kwargs).pid
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def cmdresult(args):
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"""
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Execute a command on the host and return a tuple containing the exit status and result string. stderr output
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is folded into the stdout result string.
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:param list args: command arguments
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:return: command status and stdout
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:rtype: tuple[int, str]
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"""
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cmdid = subprocess.Popen(args, stdin=open(os.devnull, "r"), stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
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# err will always be None
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result, err = cmdid.communicate()
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status = cmdid.wait()
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return status, result
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def hexdump(s, bytes_per_word=2, words_per_line=8):
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"""
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Hex dump of a string.
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:param str s: string to hex dump
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:param bytes_per_word: number of bytes per word
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:param words_per_line: number of words per line
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:return: hex dump of string
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"""
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dump = ""
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count = 0
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bytes = bytes_per_word * words_per_line
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while s:
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line = s[:bytes]
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s = s[bytes:]
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tmp = map(lambda x: ("%02x" * bytes_per_word) % x,
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zip(*[iter(map(ord, line))] * bytes_per_word))
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if len(line) % 2:
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tmp.append("%x" % ord(line[-1]))
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dump += "0x%08x: %s\n" % (count, " ".join(tmp))
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count += len(line)
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return dump[:-1]
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def filemunge(pathname, header, text):
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"""
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Insert text at the end of a file, surrounded by header comments.
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:param str pathname: file path to add text to
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:param str header: header text comments
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:param str text: text to append to file
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:return: nothing
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"""
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# prevent duplicates
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filedemunge(pathname, header)
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f = open(pathname, "a")
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f.write("# BEGIN %s\n" % header)
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f.write(text)
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f.write("# END %s\n" % header)
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f.close()
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def filedemunge(pathname, header):
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"""
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Remove text that was inserted in a file surrounded by header comments.
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:param str pathname: file path to open for removing a header
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:param str header: header text to target for removal
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:return: nothing
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"""
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f = open(pathname, "r")
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lines = f.readlines()
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f.close()
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start = None
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end = None
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for i in range(len(lines)):
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if lines[i] == "# BEGIN %s\n" % header:
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start = i
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elif lines[i] == "# END %s\n" % header:
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end = i + 1
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if start is None or end is None:
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return
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f = open(pathname, "w")
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lines = lines[:start] + lines[end:]
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f.write("".join(lines))
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f.close()
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def expandcorepath(pathname, session=None, node=None):
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"""
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Expand a file path given session information.
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:param str pathname: file path to expand
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:param core.session.Session session: core session object to expand path with
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:param core.netns.LxcNode node: node to expand path with
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:return: expanded path
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:rtype: str
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"""
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if session is not None:
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pathname = pathname.replace("~", "/home/%s" % session.user)
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pathname = pathname.replace("%SESSION%", str(session.session_id))
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pathname = pathname.replace("%SESSION_DIR%", session.session_dir)
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pathname = pathname.replace("%SESSION_USER%", session.user)
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if node is not None:
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pathname = pathname.replace("%NODE%", str(node.objid))
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pathname = pathname.replace("%NODENAME%", node.name)
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return pathname
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def sysctldevname(devname):
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"""
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Translate a device name to the name used with sysctl.
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:param str devname: device name to translate
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:return: translated device name
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:rtype: str
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"""
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if devname is None:
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return None
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return devname.replace(".", "/")
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def daemonize(rootdir="/", umask=0, close_fds=False, dontclose=(),
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stdin=os.devnull, stdout=os.devnull, stderr=os.devnull,
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stdoutmode=0644, stderrmode=0644, pidfilename=None,
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defaultmaxfd=1024):
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"""
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Run the background process as a daemon.
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:param str rootdir: root directory for daemon
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:param int umask: umask for daemon
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:param bool close_fds: flag to close file descriptors
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:param dontclose: dont close options
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:param stdin: stdin for daemon
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:param stdout: stdout for daemon
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:param stderr: stderr for daemon
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:param int stdoutmode: stdout mode
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:param int stderrmode: stderr mode
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:param str pidfilename: pid file name
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:param int defaultmaxfd: default max file descriptors
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:return: nothing
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"""
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if not hasattr(dontclose, "__contains__"):
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if not isinstance(dontclose, int):
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raise TypeError("dontclose must be an integer")
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dontclose = (int(dontclose),)
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else:
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for fd in dontclose:
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if not isinstance(fd, int):
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raise TypeError("dontclose must contain only integers")
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# redirect stdin
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if stdin:
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fd = os.open(stdin, os.O_RDONLY)
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os.dup2(fd, 0)
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os.close(fd)
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# redirect stdout
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if stdout:
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fd = os.open(stdout, os.O_WRONLY | os.O_CREAT | os.O_APPEND,
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stdoutmode)
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os.dup2(fd, 1)
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if stdout == stderr:
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os.dup2(1, 2)
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os.close(fd)
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# redirect stderr
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if stderr and (stderr != stdout):
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fd = os.open(stderr, os.O_WRONLY | os.O_CREAT | os.O_APPEND,
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stderrmode)
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os.dup2(fd, 2)
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os.close(fd)
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if os.fork():
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# parent exits
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os._exit(0)
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os.setsid()
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pid = os.fork()
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if pid:
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if pidfilename:
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try:
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f = open(pidfilename, "w")
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f.write("%s\n" % pid)
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f.close()
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except IOError:
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logger.exception("error writing to file: %s", pidfilename)
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# parent exits
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os._exit(0)
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if rootdir:
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os.chdir(rootdir)
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os.umask(umask)
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if close_fds:
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try:
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maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
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if maxfd == resource.RLIM_INFINITY:
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raise ValueError
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except:
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maxfd = defaultmaxfd
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for fd in xrange(3, maxfd):
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if fd in dontclose:
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continue
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try:
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os.close(fd)
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except IOError:
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logger.exception("error closing file descriptor")
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def readfileintodict(filename, d):
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"""
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Read key=value pairs from a file, into a dict. Skip comments; strip newline characters and spacing.
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:param str filename: file to read into a dictionary
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:param dict d: dictionary to read file into
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:return: nothing
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"""
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with open(filename, "r") as f:
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lines = f.readlines()
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for l in lines:
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if l[:1] == "#":
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continue
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try:
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key, value = l.split("=", 1)
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d[key] = value.strip()
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except ValueError:
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logger.exception("error reading file to dict: %s", filename)
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def checkforkernelmodule(name):
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"""
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Return a string if a Linux kernel module is loaded, None otherwise.
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The string is the line from /proc/modules containing the module name,
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memory size (bytes), number of loaded instances, dependencies, state,
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and kernel memory offset.
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:param str name: name of kernel module to check for
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:return: kernel module line, None otherwise
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:rtype: str
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"""
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with open("/proc/modules", "r") as f:
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for line in f:
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if line.startswith(name + " "):
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return line.rstrip()
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return None
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def _valid_module(path, file_name):
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"""
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Check if file is a valid python module.
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:param str path: path to file
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:param str file_name: file name to check
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:return: True if a valid python module file, False otherwise
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:rtype: bool
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"""
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file_path = os.path.join(path, file_name)
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if not os.path.isfile(file_path):
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return False
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if file_name.startswith("_"):
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return False
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if not file_name.endswith(".py"):
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return False
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return True
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def _is_class(module, member, clazz):
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"""
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Validates if a module member is a class and an instance of a CoreService.
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:param module: module to validate for service
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:param member: member to validate for service
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:param clazz: clazz type to check for validation
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:return: True if a valid service, False otherwise
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:rtype: bool
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"""
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if not inspect.isclass(member):
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return False
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if not issubclass(member, clazz):
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return False
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if member.__module__ != module.__name__:
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return False
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return True
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def load_classes(path, clazz):
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"""
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Dynamically load classes for use within CORE.
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:param path: path to load classes from
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:param clazz: class type expected to be inherited from for loading
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:return: list of classes loaded
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"""
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# validate path exists
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logger.info("attempting to load modules from path: %s", path)
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if not os.path.isdir(path):
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logger.warn("invalid custom module directory specified" ": %s" % path)
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# check if path is in sys.path
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parent_path = os.path.dirname(path)
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if parent_path not in sys.path:
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logger.info("adding parent path to allow imports: %s", parent_path)
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sys.path.append(parent_path)
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# retrieve potential service modules, and filter out invalid modules
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base_module = os.path.basename(path)
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module_names = os.listdir(path)
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module_names = filter(lambda x: _valid_module(path, x), module_names)
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module_names = map(lambda x: x[:-3], module_names)
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# import and add all service modules in the path
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classes = []
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for module_name in module_names:
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import_statement = "%s.%s" % (base_module, module_name)
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logger.info("importing custom module: %s", import_statement)
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try:
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module = importlib.import_module(import_statement)
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members = inspect.getmembers(module, lambda x: _is_class(module, x, clazz))
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for member in members:
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valid_class = member[1]
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classes.append(valid_class)
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except:
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logger.exception("unexpected error during import, skipping: %s", import_statement)
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return classes
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