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https://github.com/python/cpython.git
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347 lines
8.4 KiB
C
347 lines
8.4 KiB
C
/***********************************************************
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Copyright (c) 2000, BeOpen.com.
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Copyright (c) 1995-2000, Corporation for National Research Initiatives.
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Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
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All rights reserved.
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See the file "Misc/COPYRIGHT" for information on usage and
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redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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******************************************************************/
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/* select - Module containing unix select(2) call.
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Under Unix, the file descriptors are small integers.
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Under Win32, select only exists for sockets, and sockets may
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have any value except INVALID_SOCKET.
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Under BeOS, we suffer the same dichotomy as Win32; sockets can be anything
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>= 0.
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*/
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#include "Python.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_LIMITS_H
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#include <limits.h>
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#endif
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#ifdef __sgi
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/* This is missing from unistd.h */
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extern void bzero();
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#endif
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#ifndef DONT_HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#if defined(PYOS_OS2)
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#include <sys/time.h>
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#include <utils.h>
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#endif
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#ifdef MS_WINDOWS
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#include <winsock.h>
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#else
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#ifdef __BEOS__
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#include <net/socket.h>
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#define SOCKET int
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#else
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#include "myselect.h" /* Also includes mytime.h */
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#define SOCKET int
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#endif
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#endif
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static PyObject *SelectError;
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/* list of Python objects and their file descriptor */
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typedef struct {
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PyObject *obj; /* owned reference */
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SOCKET fd;
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int sentinel; /* -1 == sentinel */
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} pylist;
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static void
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reap_obj(pylist fd2obj[FD_SETSIZE + 3])
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{
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int i;
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for (i = 0; i < FD_SETSIZE + 3 && fd2obj[i].sentinel >= 0; i++) {
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Py_XDECREF(fd2obj[i].obj);
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fd2obj[i].obj = NULL;
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}
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fd2obj[0].sentinel = -1;
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}
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/* returns -1 and sets the Python exception if an error occurred, otherwise
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returns a number >= 0
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*/
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static int
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list2set(PyObject *list, fd_set *set, pylist fd2obj[FD_SETSIZE + 3])
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{
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int i;
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int max = -1;
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int index = 0;
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int len = PyList_Size(list);
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PyObject* o = NULL;
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fd2obj[0].obj = (PyObject*)0; /* set list to zero size */
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FD_ZERO(set);
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for (i = 0; i < len; i++) {
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SOCKET v;
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/* any intervening fileno() calls could decr this refcnt */
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if (!(o = PyList_GetItem(list, i)))
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return -1;
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Py_INCREF(o);
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v = PyObject_AsFileDescriptor( o );
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if (v == -1) goto finally;
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#if defined(_MSC_VER)
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max = 0; /* not used for Win32 */
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#else /* !_MSC_VER */
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if (v < 0 || v >= FD_SETSIZE) {
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PyErr_SetString(PyExc_ValueError,
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"filedescriptor out of range in select()");
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goto finally;
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}
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if (v > max)
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max = v;
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#endif /* _MSC_VER */
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FD_SET(v, set);
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/* add object and its file descriptor to the list */
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if (index >= FD_SETSIZE) {
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PyErr_SetString(PyExc_ValueError,
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"too many file descriptors in select()");
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goto finally;
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}
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fd2obj[index].obj = o;
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fd2obj[index].fd = v;
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fd2obj[index].sentinel = 0;
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fd2obj[++index].sentinel = -1;
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}
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return max+1;
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finally:
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Py_XDECREF(o);
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return -1;
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}
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/* returns NULL and sets the Python exception if an error occurred */
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static PyObject *
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set2list(fd_set *set, pylist fd2obj[FD_SETSIZE + 3])
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{
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int i, j, count=0;
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PyObject *list, *o;
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SOCKET fd;
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for (j = 0; fd2obj[j].sentinel >= 0; j++) {
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if (FD_ISSET(fd2obj[j].fd, set))
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count++;
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}
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list = PyList_New(count);
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if (!list)
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return NULL;
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i = 0;
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for (j = 0; fd2obj[j].sentinel >= 0; j++) {
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fd = fd2obj[j].fd;
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if (FD_ISSET(fd, set)) {
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#ifndef _MSC_VER
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if (fd > FD_SETSIZE) {
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PyErr_SetString(PyExc_SystemError,
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"filedescriptor out of range returned in select()");
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goto finally;
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}
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#endif
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o = fd2obj[j].obj;
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fd2obj[j].obj = NULL;
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/* transfer ownership */
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if (PyList_SetItem(list, i, o) < 0)
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goto finally;
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i++;
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}
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}
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return list;
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finally:
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Py_DECREF(list);
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return NULL;
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}
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static PyObject *
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select_select(PyObject *self, PyObject *args)
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{
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#ifdef MS_WINDOWS
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/* This would be an awful lot of stack space on Windows! */
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pylist *rfd2obj, *wfd2obj, *efd2obj;
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#else
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pylist rfd2obj[FD_SETSIZE + 3];
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pylist wfd2obj[FD_SETSIZE + 3];
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pylist efd2obj[FD_SETSIZE + 3];
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#endif
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PyObject *ifdlist, *ofdlist, *efdlist;
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PyObject *ret = NULL;
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PyObject *tout = Py_None;
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fd_set ifdset, ofdset, efdset;
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double timeout;
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struct timeval tv, *tvp;
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long seconds;
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int imax, omax, emax, max;
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int n;
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/* convert arguments */
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if (!PyArg_ParseTuple(args, "OOO|O:select",
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&ifdlist, &ofdlist, &efdlist, &tout))
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return NULL;
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if (tout == Py_None)
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tvp = (struct timeval *)0;
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else if (!PyArg_Parse(tout, "d", &timeout)) {
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PyErr_SetString(PyExc_TypeError,
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"timeout must be a float or None");
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return NULL;
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}
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else {
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if (timeout > (double)LONG_MAX) {
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PyErr_SetString(PyExc_OverflowError, "timeout period too long");
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return NULL;
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}
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seconds = (long)timeout;
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timeout = timeout - (double)seconds;
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tv.tv_sec = seconds;
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tv.tv_usec = (long)(timeout*1000000.0);
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tvp = &tv;
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}
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/* sanity check first three arguments */
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if (!PyList_Check(ifdlist) ||
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!PyList_Check(ofdlist) ||
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!PyList_Check(efdlist))
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{
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PyErr_SetString(PyExc_TypeError,
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"arguments 1-3 must be lists");
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return NULL;
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}
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#ifdef MS_WINDOWS
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/* Allocate memory for the lists */
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rfd2obj = PyMem_NEW(pylist, FD_SETSIZE + 3);
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wfd2obj = PyMem_NEW(pylist, FD_SETSIZE + 3);
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efd2obj = PyMem_NEW(pylist, FD_SETSIZE + 3);
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if (rfd2obj == NULL || wfd2obj == NULL || efd2obj == NULL) {
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if (rfd2obj) PyMem_DEL(rfd2obj);
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if (wfd2obj) PyMem_DEL(wfd2obj);
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if (efd2obj) PyMem_DEL(efd2obj);
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return NULL;
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}
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#endif
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/* Convert lists to fd_sets, and get maximum fd number
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* propagates the Python exception set in list2set()
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*/
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rfd2obj[0].sentinel = -1;
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wfd2obj[0].sentinel = -1;
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efd2obj[0].sentinel = -1;
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if ((imax=list2set(ifdlist, &ifdset, rfd2obj)) < 0)
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goto finally;
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if ((omax=list2set(ofdlist, &ofdset, wfd2obj)) < 0)
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goto finally;
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if ((emax=list2set(efdlist, &efdset, efd2obj)) < 0)
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goto finally;
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max = imax;
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if (omax > max) max = omax;
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if (emax > max) max = emax;
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Py_BEGIN_ALLOW_THREADS
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n = select(max, &ifdset, &ofdset, &efdset, tvp);
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Py_END_ALLOW_THREADS
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if (n < 0) {
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PyErr_SetFromErrno(SelectError);
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}
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else if (n == 0) {
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/* optimization */
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ifdlist = PyList_New(0);
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if (ifdlist) {
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ret = Py_BuildValue("OOO", ifdlist, ifdlist, ifdlist);
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Py_DECREF(ifdlist);
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}
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}
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else {
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/* any of these three calls can raise an exception. it's more
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convenient to test for this after all three calls... but
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is that acceptable?
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*/
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ifdlist = set2list(&ifdset, rfd2obj);
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ofdlist = set2list(&ofdset, wfd2obj);
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efdlist = set2list(&efdset, efd2obj);
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if (PyErr_Occurred())
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ret = NULL;
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else
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ret = Py_BuildValue("OOO", ifdlist, ofdlist, efdlist);
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Py_DECREF(ifdlist);
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Py_DECREF(ofdlist);
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Py_DECREF(efdlist);
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}
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finally:
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reap_obj(rfd2obj);
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reap_obj(wfd2obj);
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reap_obj(efd2obj);
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#ifdef MS_WINDOWS
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PyMem_DEL(rfd2obj);
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PyMem_DEL(wfd2obj);
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PyMem_DEL(efd2obj);
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#endif
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return ret;
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}
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static char select_doc[] =
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"select(rlist, wlist, xlist[, timeout]) -> (rlist, wlist, xlist)\n\
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\n\
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Wait until one or more file descriptors are ready for some kind of I/O.\n\
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The first three arguments are lists of file descriptors to be waited for:\n\
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rlist -- wait until ready for reading\n\
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wlist -- wait until ready for writing\n\
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xlist -- wait for an ``exceptional condition''\n\
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If only one kind of condition is required, pass [] for the other lists.\n\
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A file descriptor is either a socket or file object, or a small integer\n\
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gotten from a fileno() method call on one of those.\n\
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\n\
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The optional 4th argument specifies a timeout in seconds; it may be\n\
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a floating point number to specify fractions of seconds. If it is absent\n\
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or None, the call will never time out.\n\
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\n\
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The return value is a tuple of three lists corresponding to the first three\n\
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arguments; each contains the subset of the corresponding file descriptors\n\
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that are ready.\n\
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\n\
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*** IMPORTANT NOTICE ***\n\
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On Windows, only sockets are supported; on Unix, all file descriptors.";
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static PyMethodDef select_methods[] = {
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{"select", select_select, 1, select_doc},
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{0, 0}, /* sentinel */
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};
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static char module_doc[] =
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"This module supports asynchronous I/O on multiple file descriptors.\n\
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\n\
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*** IMPORTANT NOTICE ***\n\
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On Windows, only sockets are supported; on Unix, all file descriptors.";
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DL_EXPORT(void)
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initselect(void)
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{
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PyObject *m, *d;
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m = Py_InitModule3("select", select_methods, module_doc);
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d = PyModule_GetDict(m);
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SelectError = PyErr_NewException("select.error", NULL, NULL);
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PyDict_SetItemString(d, "error", SelectError);
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}
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