poll.c revision 289166 
1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "apr.h"
18#include "apr_poll.h"
19#include "apr_time.h"
20#include "apr_portable.h"
21#include "apr_arch_file_io.h"
22#include "apr_arch_networkio.h"
23#include "apr_arch_misc.h"
24#include "apr_arch_poll_private.h"
25
26#if defined(HAVE_POLL)
27
28#ifdef HAVE_ALLOCA_H
29#include <alloca.h>
30#endif
31
32static apr_int16_t get_event(apr_int16_t event)
33{
34    apr_int16_t rv = 0;
35
36    if (event & APR_POLLIN)
37        rv |= POLLIN;
38    if (event & APR_POLLPRI)
39        rv |= POLLPRI;
40    if (event & APR_POLLOUT)
41        rv |= POLLOUT;
42    /* POLLERR, POLLHUP, and POLLNVAL aren't valid as requested events */
43
44    return rv;
45}
46
47static apr_int16_t get_revent(apr_int16_t event)
48{
49    apr_int16_t rv = 0;
50
51    if (event & POLLIN)
52        rv |= APR_POLLIN;
53    if (event & POLLPRI)
54        rv |= APR_POLLPRI;
55    if (event & POLLOUT)
56        rv |= APR_POLLOUT;
57    if (event & POLLERR)
58        rv |= APR_POLLERR;
59    if (event & POLLHUP)
60        rv |= APR_POLLHUP;
61    if (event & POLLNVAL)
62        rv |= APR_POLLNVAL;
63
64    return rv;
65}
66
67#ifdef POLL_USES_POLL
68
69#define SMALL_POLLSET_LIMIT  8
70
71APR_DECLARE(apr_status_t) apr_poll(apr_pollfd_t *aprset, apr_int32_t num,
72                                   apr_int32_t *nsds,
73                                   apr_interval_time_t timeout)
74{
75    int i, num_to_poll;
76#ifdef HAVE_VLA
77    /* XXX: I trust that this is a segv when insufficient stack exists? */
78    struct pollfd pollset[num];
79#elif defined(HAVE_ALLOCA)
80    struct pollfd *pollset = alloca(sizeof(struct pollfd) * num);
81    if (!pollset)
82        return APR_ENOMEM;
83#else
84    struct pollfd tmp_pollset[SMALL_POLLSET_LIMIT];
85    struct pollfd *pollset;
86
87    if (num <= SMALL_POLLSET_LIMIT) {
88        pollset = tmp_pollset;
89    }
90    else {
91        /* This does require O(n) to copy the descriptors to the internal
92         * mapping.
93         */
94        pollset = malloc(sizeof(struct pollfd) * num);
95        /* The other option is adding an apr_pool_abort() fn to invoke
96         * the pool's out of memory handler
97         */
98        if (!pollset)
99            return APR_ENOMEM;
100    }
101#endif
102    for (i = 0; i < num; i++) {
103        if (aprset[i].desc_type == APR_POLL_SOCKET) {
104            pollset[i].fd = aprset[i].desc.s->socketdes;
105        }
106        else if (aprset[i].desc_type == APR_POLL_FILE) {
107            pollset[i].fd = aprset[i].desc.f->filedes;
108        }
109        else {
110            break;
111        }
112        pollset[i].events = get_event(aprset[i].reqevents);
113    }
114    num_to_poll = i;
115
116    if (timeout > 0) {
117        timeout /= 1000; /* convert microseconds to milliseconds */
118    }
119
120    i = poll(pollset, num_to_poll, timeout);
121    (*nsds) = i;
122
123    if (i > 0) { /* poll() sets revents only if an event was signalled;
124                  * we don't promise to set rtnevents unless an event
125                  * was signalled
126                  */
127        for (i = 0; i < num; i++) {
128            aprset[i].rtnevents = get_revent(pollset[i].revents);
129        }
130    }
131
132#if !defined(HAVE_VLA) && !defined(HAVE_ALLOCA)
133    if (num > SMALL_POLLSET_LIMIT) {
134        free(pollset);
135    }
136#endif
137
138    if ((*nsds) < 0) {
139        return apr_get_netos_error();
140    }
141    if ((*nsds) == 0) {
142        return APR_TIMEUP;
143    }
144    return APR_SUCCESS;
145}
146
147
148#endif /* POLL_USES_POLL */
149
150struct apr_pollset_private_t
151{
152    struct pollfd *pollset;
153    apr_pollfd_t *query_set;
154    apr_pollfd_t *result_set;
155};
156
157static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
158                                        apr_uint32_t size,
159                                        apr_pool_t *p,
160                                        apr_uint32_t flags)
161{
162    if (flags & APR_POLLSET_THREADSAFE) {
163        return APR_ENOTIMPL;
164    }
165#ifdef WIN32
166    if (!APR_HAVE_LATE_DLL_FUNC(WSAPoll)) {
167        return APR_ENOTIMPL;
168    }
169#endif
170    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
171    pollset->p->pollset = apr_palloc(p, size * sizeof(struct pollfd));
172    pollset->p->query_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
173    pollset->p->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
174
175    return APR_SUCCESS;
176}
177
178static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
179                                     const apr_pollfd_t *descriptor)
180{
181    if (pollset->nelts == pollset->nalloc) {
182        return APR_ENOMEM;
183    }
184
185    pollset->p->query_set[pollset->nelts] = *descriptor;
186
187    if (descriptor->desc_type == APR_POLL_SOCKET) {
188        pollset->p->pollset[pollset->nelts].fd = descriptor->desc.s->socketdes;
189    }
190    else {
191#if APR_FILES_AS_SOCKETS
192        pollset->p->pollset[pollset->nelts].fd = descriptor->desc.f->filedes;
193#else
194        if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
195            descriptor->desc.f == pollset->wakeup_pipe[0])
196            pollset->p->pollset[pollset->nelts].fd = (SOCKET)descriptor->desc.f->filedes;
197        else
198            return APR_EBADF;
199#endif
200    }
201    pollset->p->pollset[pollset->nelts].events =
202        get_event(descriptor->reqevents);
203    pollset->nelts++;
204
205    return APR_SUCCESS;
206}
207
208static apr_status_t impl_pollset_remove(apr_pollset_t *pollset,
209                                        const apr_pollfd_t *descriptor)
210{
211    apr_uint32_t i;
212
213    for (i = 0; i < pollset->nelts; i++) {
214        if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
215            /* Found an instance of the fd: remove this and any other copies */
216            apr_uint32_t dst = i;
217            apr_uint32_t old_nelts = pollset->nelts;
218            pollset->nelts--;
219            for (i++; i < old_nelts; i++) {
220                if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
221                    pollset->nelts--;
222                }
223                else {
224                    pollset->p->pollset[dst] = pollset->p->pollset[i];
225                    pollset->p->query_set[dst] = pollset->p->query_set[i];
226                    dst++;
227                }
228            }
229            return APR_SUCCESS;
230        }
231    }
232
233    return APR_NOTFOUND;
234}
235
236static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
237                                      apr_interval_time_t timeout,
238                                      apr_int32_t *num,
239                                      const apr_pollfd_t **descriptors)
240{
241    int ret;
242    apr_status_t rv = APR_SUCCESS;
243
244#ifdef WIN32
245    /* WSAPoll() requires at least one socket. */
246    if (pollset->nelts == 0) {
247        *num = 0;
248        if (timeout > 0) {
249            apr_sleep(timeout);
250            return APR_TIMEUP;
251        }
252        return APR_SUCCESS;
253    }
254    if (timeout > 0) {
255        timeout /= 1000;
256    }
257    ret = WSAPoll(pollset->p->pollset, pollset->nelts, (int)timeout);
258#else
259    if (timeout > 0) {
260        timeout /= 1000;
261    }
262    ret = poll(pollset->p->pollset, pollset->nelts, timeout);
263#endif
264    (*num) = ret;
265    if (ret < 0) {
266        return apr_get_netos_error();
267    }
268    else if (ret == 0) {
269        return APR_TIMEUP;
270    }
271    else {
272        apr_uint32_t i, j;
273
274        for (i = 0, j = 0; i < pollset->nelts; i++) {
275            if (pollset->p->pollset[i].revents != 0) {
276                /* Check if the polled descriptor is our
277                 * wakeup pipe. In that case do not put it result set.
278                 */
279                if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
280                    pollset->p->query_set[i].desc_type == APR_POLL_FILE &&
281                    pollset->p->query_set[i].desc.f == pollset->wakeup_pipe[0]) {
282                        apr_pollset_drain_wakeup_pipe(pollset);
283                        rv = APR_EINTR;
284                }
285                else {
286                    pollset->p->result_set[j] = pollset->p->query_set[i];
287                    pollset->p->result_set[j].rtnevents =
288                        get_revent(pollset->p->pollset[i].revents);
289                    j++;
290                }
291            }
292        }
293        if (((*num) = j) > 0)
294            rv = APR_SUCCESS;
295    }
296    if (descriptors && (*num))
297        *descriptors = pollset->p->result_set;
298    return rv;
299}
300
301static apr_pollset_provider_t impl = {
302    impl_pollset_create,
303    impl_pollset_add,
304    impl_pollset_remove,
305    impl_pollset_poll,
306    NULL,
307    "poll"
308};
309
310apr_pollset_provider_t *apr_pollset_provider_poll = &impl;
311
312/* Poll method pollcb.
313 * This is probably usable only for WIN32 having WSAPoll
314 */
315static apr_status_t impl_pollcb_create(apr_pollcb_t *pollcb,
316                                       apr_uint32_t size,
317                                       apr_pool_t *p,
318                                       apr_uint32_t flags)
319{
320#if APR_HAS_THREADS
321    return APR_ENOTIMPL;
322#else
323    pollcb->fd = -1;
324#ifdef WIN32
325    if (!APR_HAVE_LATE_DLL_FUNC(WSAPoll)) {
326        return APR_ENOTIMPL;
327    }
328#endif
329
330    pollcb->pollset.ps = apr_palloc(p, size * sizeof(struct pollfd));
331    pollcb->copyset = apr_palloc(p, size * sizeof(apr_pollfd_t *));
332
333    return APR_SUCCESS;
334#endif
335}
336
337static apr_status_t impl_pollcb_add(apr_pollcb_t *pollcb,
338                                    apr_pollfd_t *descriptor)
339{
340    if (pollcb->nelts == pollcb->nalloc) {
341        return APR_ENOMEM;
342    }
343
344    if (descriptor->desc_type == APR_POLL_SOCKET) {
345        pollcb->pollset.ps[pollcb->nelts].fd = descriptor->desc.s->socketdes;
346    }
347    else {
348#if APR_FILES_AS_SOCKETS
349        pollcb->pollset.ps[pollcb->nelts].fd = descriptor->desc.f->filedes;
350#else
351        return APR_EBADF;
352#endif
353    }
354
355    pollcb->pollset.ps[pollcb->nelts].events =
356        get_event(descriptor->reqevents);
357    pollcb->copyset[pollcb->nelts] = descriptor;
358    pollcb->nelts++;
359
360    return APR_SUCCESS;
361}
362
363static apr_status_t impl_pollcb_remove(apr_pollcb_t *pollcb,
364                                       apr_pollfd_t *descriptor)
365{
366    apr_uint32_t i;
367
368    for (i = 0; i < pollcb->nelts; i++) {
369        if (descriptor->desc.s == pollcb->copyset[i]->desc.s) {
370            /* Found an instance of the fd: remove this and any other copies */
371            apr_uint32_t dst = i;
372            apr_uint32_t old_nelts = pollcb->nelts;
373            pollcb->nelts--;
374            for (i++; i < old_nelts; i++) {
375                if (descriptor->desc.s == pollcb->copyset[i]->desc.s) {
376                    pollcb->nelts--;
377                }
378                else {
379                    pollcb->pollset.ps[dst] = pollcb->pollset.ps[i];
380                    pollcb->copyset[dst] = pollcb->copyset[i];
381                    dst++;
382                }
383            }
384            return APR_SUCCESS;
385        }
386    }
387
388    return APR_NOTFOUND;
389}
390
391static apr_status_t impl_pollcb_poll(apr_pollcb_t *pollcb,
392                                     apr_interval_time_t timeout,
393                                     apr_pollcb_cb_t func,
394                                     void *baton)
395{
396    int ret;
397    apr_status_t rv = APR_SUCCESS;
398    apr_uint32_t i;
399
400#ifdef WIN32
401    /* WSAPoll() requires at least one socket. */
402    if (pollcb->nelts == 0) {
403        if (timeout > 0) {
404            apr_sleep(timeout);
405            return APR_TIMEUP;
406        }
407        return APR_SUCCESS;
408    }
409    if (timeout > 0) {
410        timeout /= 1000;
411    }
412    ret = WSAPoll(pollcb->pollset.ps, pollcb->nelts, (int)timeout);
413#else
414    if (timeout > 0) {
415        timeout /= 1000;
416    }
417    ret = poll(pollcb->pollset.ps, pollcb->nelts, timeout);
418#endif
419    if (ret < 0) {
420        return apr_get_netos_error();
421    }
422    else if (ret == 0) {
423        return APR_TIMEUP;
424    }
425    else {
426        for (i = 0; i < pollcb->nelts; i++) {
427            if (pollcb->pollset.ps[i].revents != 0) {
428                apr_pollfd_t *pollfd = pollcb->copyset[i];
429                pollfd->rtnevents = get_revent(pollcb->pollset.ps[i].revents);
430                rv = func(baton, pollfd);
431                if (rv) {
432                    return rv;
433                }
434            }
435        }
436    }
437    return rv;
438}
439
440static apr_pollcb_provider_t impl_cb = {
441    impl_pollcb_create,
442    impl_pollcb_add,
443    impl_pollcb_remove,
444    impl_pollcb_poll,
445    "poll"
446};
447
448apr_pollcb_provider_t *apr_pollcb_provider_poll = &impl_cb;
449
450#endif /* HAVE_POLL */
451