def test_get_process_info(self):
# Ensure that get_process_info() called for oud pid returns information
# about ourselves.
pinfo = platform.get_process_info(os.getpid())
self.assertIsInstance(pinfo, tuple)
self.assertEqual(pinfo.exe, os.path.realpath(sys.executable))
self.assertEqual(pinfo.cmdline[1:], sys.argv)
if hasattr(os, 'getuid'):
self.assertEqual(pinfo.uid, os.getuid())
if hasattr(os, 'getgid'):
self.assertEqual(pinfo.gid, os.getgid())
def lock_file(filename):
"""Lock the file *filename*.
On success, an opaque object that can be passed to :meth:`unlock_file` is
returned. On failure, an :class:`OSError` exception is raised.
"""
# This uses the lockf() primitive. It has two major drawbacks which is that
# it is per process (making it harder to test) and that it releases the
# lock as soon as *any* fd referring to the file is closed (making it
# more fragile). However it works on NFS so on balance I think I can live
# with the drawbacks.
# See also: http://0pointer.de/blog/projects/locking.html
lockname = '{0}-lock'.format(filename)
flock = open(lockname, 'a+')
try:
fcntl.lockf(flock.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
except IOError as e:
if e.errno not in (errno.EACCES, errno.EAGAIN):
flock.close()
raise
lockinfo = {}
flock.seek(0)
for line in flock:
key, value = line.split(':')
lockinfo[key.lower()] = value.strip()
flock.close()
pid = int(lockinfo['pid'])
from bluepass import platform
pinfo = platform.get_process_info(pid)
pinfo = 'alive; cmdline={0!r}'.format(' '.join(pinfo.cmdline)) if pinfo else 'remote?'
msg = '{0}: locked by process {1} ({2})'.format(filename, pid, pinfo)
raise OSError(e.errno, msg)
flock.truncate()
flock.write('PID: {0}\n'.format(os.getpid()))
flock.write('Command: {0}\n'.format(' '.join(sys.argv)))
flock.write('Hostname: {0}\n'.format(socket.gethostname()))
flock.flush()
return flock
