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/*
* _obnammodule.c -- Python extensions for Obna
*
* Copyright (C) 2008, 2009 Lars Wirzenius <liw@liw.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* This is a Python extension module written for Obnam, the backup
* software.
*
* This module provides a way to call the posix_fadvise function from
* Python. Obnam uses this to use set the POSIX_FADV_SEQUENTIAL and
* POSIX_FADV_DONTNEED flags, to make sure the kernel knows that it will
* read files sequentially and that the data does not need to be cached.
* This makes Obnam not trash the disk buffer cache, which is nice.
*/
#include <Python.h>
#define _XOPEN_SOURCE 600
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
static PyObject *
fadvise_dontneed(PyObject *self, PyObject *args)
{
int fd;
/* Can't use off_t for offset and len, since PyArg_ParseTuple
doesn't know it. */
unsigned long long offset;
unsigned long long len;
int ret;
if (!PyArg_ParseTuple(args, "iLL", &fd, &offset, &len))
return NULL;
ret = posix_fadvise(fd, offset, len, POSIX_FADV_DONTNEED);
return Py_BuildValue("i", ret);
}
static PyObject *
lutimes_wrapper(PyObject *self, PyObject *args)
{
int ret;
long atime;
long mtime;
struct timeval tv[2];
const char *filename;
if (!PyArg_ParseTuple(args, "sll", &filename, &atime, &mtime))
return NULL;
tv[0].tv_sec = atime;
tv[0].tv_usec = 0;
tv[1].tv_sec = mtime;
tv[1].tv_usec = 0;
ret = lutimes(filename, tv);
if (ret == -1)
ret = errno;
return Py_BuildValue("i", ret);
}
static PyMethodDef methods[] = {
{"fadvise_dontneed", fadvise_dontneed, METH_VARARGS,
"Call posix_fadvise(2) with POSIX_FADV_DONTNEED argument."},
{"lutimes", lutimes_wrapper, METH_VARARGS,
"lutimes(2) wrapper; args are filename, atime, and mtime."},
{NULL, NULL, 0, NULL} /* Sentinel */
};
PyMODINIT_FUNC
init_obnam(void)
{
(void) Py_InitModule("_obnam", methods);
}
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