root / lib / utils / mlock.py @ d529599f
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1 | 36a4acd4 | Michael Hanselmann | #
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2 | 36a4acd4 | Michael Hanselmann | #
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3 | 36a4acd4 | Michael Hanselmann | |
4 | 36a4acd4 | Michael Hanselmann | # Copyright (C) 2009, 2010, 2011 Google Inc.
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5 | 36a4acd4 | Michael Hanselmann | #
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6 | 36a4acd4 | Michael Hanselmann | # This program is free software; you can redistribute it and/or modify
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7 | 36a4acd4 | Michael Hanselmann | # it under the terms of the GNU General Public License as published by
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8 | 36a4acd4 | Michael Hanselmann | # the Free Software Foundation; either version 2 of the License, or
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9 | 36a4acd4 | Michael Hanselmann | # (at your option) any later version.
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10 | 36a4acd4 | Michael Hanselmann | #
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11 | 36a4acd4 | Michael Hanselmann | # This program is distributed in the hope that it will be useful, but
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12 | 36a4acd4 | Michael Hanselmann | # WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | 36a4acd4 | Michael Hanselmann | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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14 | 36a4acd4 | Michael Hanselmann | # General Public License for more details.
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15 | 36a4acd4 | Michael Hanselmann | #
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16 | 36a4acd4 | Michael Hanselmann | # You should have received a copy of the GNU General Public License
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17 | 36a4acd4 | Michael Hanselmann | # along with this program; if not, write to the Free Software
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18 | 36a4acd4 | Michael Hanselmann | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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19 | 36a4acd4 | Michael Hanselmann | # 02110-1301, USA.
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20 | 36a4acd4 | Michael Hanselmann | |
21 | 36a4acd4 | Michael Hanselmann | """Wrapper around mlockall(2).
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22 | 36a4acd4 | Michael Hanselmann |
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23 | 36a4acd4 | Michael Hanselmann | """
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24 | 36a4acd4 | Michael Hanselmann | |
25 | 36a4acd4 | Michael Hanselmann | import os |
26 | 36a4acd4 | Michael Hanselmann | import logging |
27 | 36a4acd4 | Michael Hanselmann | |
28 | 36a4acd4 | Michael Hanselmann | from ganeti import errors |
29 | 36a4acd4 | Michael Hanselmann | |
30 | 36a4acd4 | Michael Hanselmann | try:
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31 | b459a848 | Andrea Spadaccini | # pylint: disable=F0401
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32 | 36a4acd4 | Michael Hanselmann | import ctypes |
33 | 36a4acd4 | Michael Hanselmann | except ImportError: |
34 | 36a4acd4 | Michael Hanselmann | ctypes = None
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35 | 36a4acd4 | Michael Hanselmann | |
36 | 36a4acd4 | Michael Hanselmann | |
37 | 5fe4a65b | Michael Hanselmann | # Flags for mlockall(2) (from bits/mman.h)
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38 | 36a4acd4 | Michael Hanselmann | _MCL_CURRENT = 1
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39 | 36a4acd4 | Michael Hanselmann | _MCL_FUTURE = 2
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40 | 36a4acd4 | Michael Hanselmann | |
41 | 36a4acd4 | Michael Hanselmann | |
42 | 36a4acd4 | Michael Hanselmann | def Mlockall(_ctypes=ctypes): |
43 | 36a4acd4 | Michael Hanselmann | """Lock current process' virtual address space into RAM.
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44 | 36a4acd4 | Michael Hanselmann |
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45 | 5fe4a65b | Michael Hanselmann | This is equivalent to the C call C{mlockall(MCL_CURRENT | MCL_FUTURE)}. See
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46 | 5fe4a65b | Michael Hanselmann | mlockall(2) for more details. This function requires the C{ctypes} module.
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47 | 36a4acd4 | Michael Hanselmann |
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48 | 5fe4a65b | Michael Hanselmann | @raises errors.NoCtypesError: If the C{ctypes} module is not found
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49 | 36a4acd4 | Michael Hanselmann |
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50 | 36a4acd4 | Michael Hanselmann | """
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51 | 36a4acd4 | Michael Hanselmann | if _ctypes is None: |
52 | 36a4acd4 | Michael Hanselmann | raise errors.NoCtypesError()
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53 | 36a4acd4 | Michael Hanselmann | |
54 | 142c1ad0 | Guido Trotter | try:
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55 | 142c1ad0 | Guido Trotter | libc = _ctypes.cdll.LoadLibrary("libc.so.6")
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56 | 142c1ad0 | Guido Trotter | except EnvironmentError, err: |
57 | 142c1ad0 | Guido Trotter | logging.error("Failure trying to load libc: %s", err)
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58 | 142c1ad0 | Guido Trotter | libc = None
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59 | 142c1ad0 | Guido Trotter | if libc is None: |
60 | 142c1ad0 | Guido Trotter | logging.error("Cannot set memory lock, ctypes cannot load libc")
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61 | 142c1ad0 | Guido Trotter | return
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62 | 142c1ad0 | Guido Trotter | |
63 | 5fe4a65b | Michael Hanselmann | # The ctypes module before Python 2.6 does not have built-in functionality to
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64 | 5fe4a65b | Michael Hanselmann | # access the global errno global (which, depending on the libc and build
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65 | 5fe4a65b | Michael Hanselmann | # options, is per thread), where function error codes are stored. Use GNU
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66 | 5fe4a65b | Michael Hanselmann | # libc's way to retrieve errno(3) instead, which is to use the pointer named
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67 | 5fe4a65b | Michael Hanselmann | # "__errno_location" (see errno.h and bits/errno.h).
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68 | 142c1ad0 | Guido Trotter | # pylint: disable=W0212
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69 | 142c1ad0 | Guido Trotter | libc.__errno_location.restype = _ctypes.POINTER(_ctypes.c_int) |
70 | 142c1ad0 | Guido Trotter | |
71 | 142c1ad0 | Guido Trotter | if libc.mlockall(_MCL_CURRENT | _MCL_FUTURE):
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72 | 142c1ad0 | Guido Trotter | # pylint: disable=W0212
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73 | 142c1ad0 | Guido Trotter | logging.error("Cannot set memory lock: %s",
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74 | 142c1ad0 | Guido Trotter | os.strerror(libc.__errno_location().contents.value)) |
75 | 142c1ad0 | Guido Trotter | return
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76 | 142c1ad0 | Guido Trotter | |
77 | 142c1ad0 | Guido Trotter | logging.debug("Memory lock set") |