mirror of
https://github.com/AdaCore/git-hooks.git
synced 2026-02-12 12:43:11 -08:00
a2909b2c8d
In preparation for the transition to Python 3, convert to using the
print function. The special import
from __future__ import print_function
in Python 2.7 makes "print" become the function and not the statement.
In Python 3, it has no effect. Once the transition is done and we
exclusively use Python 3, we can simply remove the imports.
The testsuite shows no regressions.
91 lines
2.4 KiB
Python
91 lines
2.4 KiB
Python
"""A module to handle daemonization...
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"""
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from __future__ import print_function
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import os
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import sys
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from syslog import syslog
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def daemonize(output_fd=None):
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"""Create a daemon process.
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PARAMETERS
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output_fd: If not none, a file descriptor where stdout and
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stderr should be redirected.
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RETURN VALUE
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This function returns True for the child (daemon) process,
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while it returns False for the parent process.
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"""
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# Perform the first fork.
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try:
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pid = os.fork()
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if pid > 0:
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# In the parent. We can now return.
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return False
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except OSError, e:
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sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
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return False
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# Decouple ourselves from the parent environment.
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os.chdir("/")
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os.umask(0)
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os.setsid()
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# Perform the second fork, to daemonize ourselves.
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try:
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pid = os.fork()
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if pid > 0:
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# In the second parent. Exit.
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sys.exit(0)
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except OSError, e:
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syslog("git-hooks: fork #2 failed: (%d) %s" % (e.errno, e.strerror))
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sys.exit(1)
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# Flush the output...
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for f in sys.stdout, sys.stderr:
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f.flush()
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# Perform the input/output redirection.
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os.close(0)
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os.dup2(os.open('/dev/null', os.O_RDONLY), 0)
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if output_fd is None: # pragma: no cover (never true in testsuite mode)
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output_fd = os.open('/dev/null', os.O_WRONLY)
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os.close(1)
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os.dup2(output_fd, 1)
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os.close(2)
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os.dup2(output_fd, 2)
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return True
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def run_in_daemon(fun):
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"""Run the given callbable in a daemon process.
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In GIT_HOOKS_TESTSUITE_MODE, the function's stdout and stderr
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is redirected to a pipe and then re-printed on our stdout.
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But this is only for testing purposes. In normal mode,
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the function's stdout/stderr, as well as stdin are redirected
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to /dev/null.
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PARAMETERS
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fun: A callable.
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"""
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daemon_pipe = (None, None)
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if 'GIT_HOOKS_TESTSUITE_MODE' in os.environ:
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daemon_pipe = os.pipe()
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in_daemon = daemonize(daemon_pipe[1])
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if in_daemon:
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fun()
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sys.exit(0)
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else:
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if daemon_pipe[0] is not None:
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os.close(daemon_pipe[1])
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daemon_stdout = os.fdopen(daemon_pipe[0])
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print(daemon_stdout.read(), file=sys.stderr, end='')
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daemon_stdout.close()
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