147 lines
3 KiB
C
147 lines
3 KiB
C
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/*
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* CORE
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* Copyright (c)2010-2012 the Boeing Company.
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* See the LICENSE file included in this distribution.
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*
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* author: Tom Goff <thomas.goff@boeing.com>
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*
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* netnsmodule.c
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*
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* Python module C bindings providing nsfork and nsexecvp methods for
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* forking a child process into a new namespace, with nsexecvp executing a
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* new program using the default search path.
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*
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*/
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#include <Python.h>
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#include <err.h>
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#include <signal.h>
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#include "netns.h"
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/* parts taken from python/trunk/Modules/posixmodule.c */
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static void free_string_array(char **array, Py_ssize_t count)
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{
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Py_ssize_t i;
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for (i = 0; i < count; i++)
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PyMem_Free(array[i]);
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PyMem_DEL(array);
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}
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static PyObject *netns_nsexecvp(PyObject *self, PyObject *args)
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{
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pid_t pid;
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char **argv;
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Py_ssize_t i, argc;
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PyObject *(*getitem)(PyObject *, Py_ssize_t);
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/* args should be a list or tuple of strings */
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if (PyList_Check(args))
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{
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argc = PyList_Size(args);
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getitem = PyList_GetItem;
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}
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else if (PyTuple_Check(args))
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{
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argc = PyTuple_Size(args);
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getitem = PyTuple_GetItem;
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}
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else
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{
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PyErr_SetString(PyExc_TypeError,
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"netns_nsexecvp() args must be a tuple or list");
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return NULL;
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}
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argv = PyMem_NEW(char *, argc + 1);
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if (argv == NULL)
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return PyErr_NoMemory();
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for (i = 0; i < argc; i++)
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{
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if (!PyArg_Parse((*getitem)(args, i), "et",
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Py_FileSystemDefaultEncoding, &argv[i]))
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{
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free_string_array(argv, i);
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PyErr_SetString(PyExc_TypeError,
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"netns_nsexecvp() args must contain only strings");
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return NULL;
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}
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}
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argv[argc] = NULL;
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pid = nsexecvp(argv);
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free_string_array(argv, argc);
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if (pid < 0)
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return PyErr_SetFromErrno(PyExc_OSError);
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else
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return PyInt_FromLong(pid);
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}
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static PyObject *netns_nsfork(PyObject *self, PyObject *args)
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{
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int flags;
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pid_t pid;
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if (!PyArg_ParseTuple(args, "i", &flags))
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return NULL;
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pid = nsfork(flags);
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if (pid < 0)
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return PyErr_SetFromErrno(PyExc_OSError);
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if (pid == 0) /* child */
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PyOS_AfterFork();
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return PyInt_FromLong(pid);
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}
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static PyMethodDef netns_methods[] = {
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{"nsfork", netns_nsfork, METH_VARARGS,
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"nsfork(cloneflags) -> int\n\n"
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"Fork a child process into a new namespace using the Linux clone()\n"
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"system call.\n\n"
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"cloneflags: additional flags passed to clone()"},
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{"nsexecvp", netns_nsexecvp, METH_VARARGS,
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"nsexecvp(args...) -> int\n\n"
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"Fork a child process into a new namespace using the Linux clone()\n"
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"system call and have the child execute a new program using the\n"
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"default search path.\n\n"
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"args: the executable file name followed by command arguments"},
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{NULL, NULL, 0, NULL},
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};
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PyMODINIT_FUNC initnetns(void)
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{
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PyObject *m;
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m = Py_InitModule("netns", netns_methods);
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if (m == NULL)
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return;
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#define MODADDINT(x) \
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do { \
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PyObject *tmp = Py_BuildValue("i", x); \
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if (tmp) \
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{ \
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Py_INCREF(tmp); \
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PyModule_AddObject(m, #x, tmp); \
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} \
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} while (0)
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MODADDINT(CLONE_VFORK);
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#undef MODADDINT
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return;
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}
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