/nsock/src/engine_poll.c
C | 427 lines | 259 code | 88 blank | 80 comment | 52 complexity | 2c3035516aaa91b4f8c1d5453dfef044 MD5 | raw file
Possible License(s): BSD-3-Clause, GPL-2.0, Apache-2.0, LGPL-2.0, LGPL-2.1, MIT
- /***************************************************************************
- * engine_poll.c -- poll(2) based IO engine. *
- * *
- ***********************IMPORTANT NSOCK LICENSE TERMS***********************
- * *
- * The nsock parallel socket event library is (C) 1999-2015 Insecure.Com *
- * LLC This library is free software; you may redistribute and/or *
- * modify it under the terms of the GNU General Public License as *
- * published by the Free Software Foundation; Version 2. This guarantees *
- * your right to use, modify, and redistribute this software under certain *
- * conditions. If this license is unacceptable to you, Insecure.Com LLC *
- * may be willing to sell alternative licenses (contact *
- * sales@insecure.com ). *
- * *
- * As a special exception to the GPL terms, Insecure.Com LLC grants *
- * permission to link the code of this program with any version of the *
- * OpenSSL library which is distributed under a license identical to that *
- * listed in the included docs/licenses/OpenSSL.txt file, and distribute *
- * linked combinations including the two. You must obey the GNU GPL in all *
- * respects for all of the code used other than OpenSSL. If you modify *
- * this file, you may extend this exception to your version of the file, *
- * but you are not obligated to do so. *
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- * agreement takes precedence over this comment. *
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- * Source is provided to this software because we believe users have a *
- * right to know exactly what a program is going to do before they run it. *
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- * Source code also allows you to port Nmap to new platforms, fix bugs, *
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- * unlimited, non-exclusive right to reuse, modify, and relicense the *
- * code. Nmap will always be available Open Source, but this is important *
- * because the inability to relicense code has caused devastating problems *
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- * occasionally relicense the code to third parties as discussed above. *
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- * *
- * 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 v2.0 for more details *
- * (http://www.gnu.org/licenses/gpl-2.0.html). *
- * *
- ***************************************************************************/
- /* $Id$ */
- #ifndef WIN32
- /* Allow the use of POLLRDHUP, if available. */
- #define _GNU_SOURCE
- #endif
- #ifdef HAVE_CONFIG_H
- #include "nsock_config.h"
- #elif WIN32
- #include "nsock_winconfig.h"
- #endif
- #if HAVE_POLL
- #include <errno.h>
- #ifndef WIN32
- #include <poll.h>
- #else
- #include <Winsock2.h>
- #endif /* ^WIN32 */
- #include "nsock_internal.h"
- #include "nsock_log.h"
- #if HAVE_PCAP
- #include "nsock_pcap.h"
- #endif
- #define EV_LIST_INIT_SIZE 1024
- #ifdef WIN32
- #define Poll WSAPoll
- #define POLLFD WSAPOLLFD
- #else
- #define Poll poll
- #define POLLFD struct pollfd
- #endif
- #ifdef WIN32
- #define POLL_R_FLAGS (POLLIN)
- #else
- #define POLL_R_FLAGS (POLLIN | POLLPRI)
- #endif /* WIN32 */
- #define POLL_W_FLAGS POLLOUT
- #ifdef POLLRDHUP
- #define POLL_X_FLAGS (POLLERR | POLLHUP | POLLRDHUP)
- #else
- /* POLLRDHUP was introduced later and might be unavailable on older systems. */
- #define POLL_X_FLAGS (POLLERR | POLLHUP)
- #endif /* POLLRDHUP */
- /* --- ENGINE INTERFACE PROTOTYPES --- */
- static int poll_init(struct npool *nsp);
- static void poll_destroy(struct npool *nsp);
- static int poll_iod_register(struct npool *nsp, struct niod *iod, int ev);
- static int poll_iod_unregister(struct npool *nsp, struct niod *iod);
- static int poll_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr);
- static int poll_loop(struct npool *nsp, int msec_timeout);
- /* ---- ENGINE DEFINITION ---- */
- struct io_engine engine_poll = {
- "poll",
- poll_init,
- poll_destroy,
- poll_iod_register,
- poll_iod_unregister,
- poll_iod_modify,
- poll_loop
- };
- /* --- INTERNAL PROTOTYPES --- */
- static void iterate_through_event_lists(struct npool *nsp);
- /* defined in nsock_core.c */
- void process_iod_events(struct npool *nsp, struct niod *nsi, int ev);
- void process_event(struct npool *nsp, gh_list_t *evlist, struct nevent *nse, int ev);
- void process_expired_events(struct npool *nsp);
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- int pcap_read_on_nonselect(struct npool *nsp);
- #endif
- #endif
- /* defined in nsock_event.c */
- void update_first_events(struct nevent *nse);
- extern struct timeval nsock_tod;
- /*
- * Engine specific data structure
- */
- struct poll_engine_info {
- int capacity;
- int max_fd;
- /* index of the highest poll event */
- POLLFD *events;
- };
- static inline int lower_max_fd(struct poll_engine_info *pinfo) {
- do {
- pinfo->max_fd--;
- } while (pinfo->max_fd >= 0 && pinfo->events[pinfo->max_fd].fd == -1);
- return pinfo->max_fd;
- }
- static inline int evlist_grow(struct poll_engine_info *pinfo) {
- int i;
- i = pinfo->capacity;
- if (pinfo->capacity == 0) {
- pinfo->capacity = EV_LIST_INIT_SIZE;
- pinfo->events = (POLLFD *)safe_malloc(sizeof(POLLFD) * pinfo->capacity);
- } else {
- pinfo->capacity *= 2;
- pinfo->events = (POLLFD *)safe_realloc(pinfo->events, sizeof(POLLFD) * pinfo->capacity);
- }
- while (i < pinfo->capacity) {
- pinfo->events[i].fd = -1;
- pinfo->events[i].events = 0;
- pinfo->events[i].revents = 0;
- i++;
- }
- return pinfo->capacity;
- }
- int poll_init(struct npool *nsp) {
- struct poll_engine_info *pinfo;
- pinfo = (struct poll_engine_info *)safe_malloc(sizeof(struct poll_engine_info));
- pinfo->capacity = 0;
- pinfo->max_fd = -1;
- evlist_grow(pinfo);
- nsp->engine_data = (void *)pinfo;
- return 1;
- }
- void poll_destroy(struct npool *nsp) {
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- assert(pinfo != NULL);
- free(pinfo->events);
- free(pinfo);
- }
- int poll_iod_register(struct npool *nsp, struct niod *iod, int ev) {
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- int sd;
- assert(!IOD_PROPGET(iod, IOD_REGISTERED));
- iod->watched_events = ev;
- sd = nsock_iod_get_sd(iod);
- while (pinfo->capacity < sd + 1)
- evlist_grow(pinfo);
- pinfo->events[sd].fd = sd;
- pinfo->events[sd].events = 0;
- pinfo->events[sd].revents = 0;
- pinfo->max_fd = MAX(pinfo->max_fd, sd);
- if (ev & EV_READ)
- pinfo->events[sd].events |= POLL_R_FLAGS;
- if (ev & EV_WRITE)
- pinfo->events[sd].events |= POLL_W_FLAGS;
- #ifndef WIN32
- if (ev & EV_EXCEPT)
- pinfo->events[sd].events |= POLL_X_FLAGS;
- #endif
- IOD_PROPSET(iod, IOD_REGISTERED);
- return 1;
- }
- int poll_iod_unregister(struct npool *nsp, struct niod *iod) {
- iod->watched_events = EV_NONE;
- /* some IODs can be unregistered here if they're associated to an event that was
- * immediately completed */
- if (IOD_PROPGET(iod, IOD_REGISTERED)) {
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- int sd;
- sd = nsock_iod_get_sd(iod);
- pinfo->events[sd].fd = -1;
- pinfo->events[sd].events = 0;
- pinfo->events[sd].revents = 0;
- if (pinfo->max_fd == sd)
- lower_max_fd(pinfo);
- IOD_PROPCLR(iod, IOD_REGISTERED);
- }
- return 1;
- }
- int poll_iod_modify(struct npool *nsp, struct niod *iod, int ev_set, int ev_clr) {
- int sd;
- int new_events;
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- assert((ev_set & ev_clr) == 0);
- assert(IOD_PROPGET(iod, IOD_REGISTERED));
- new_events = iod->watched_events;
- new_events |= ev_set;
- new_events &= ~ev_clr;
- if (new_events == iod->watched_events)
- return 1; /* nothing to do */
- iod->watched_events = new_events;
- sd = nsock_iod_get_sd(iod);
- pinfo->events[sd].fd = sd;
- pinfo->events[sd].events = 0;
- /* regenerate the current set of events for this IOD */
- if (iod->watched_events & EV_READ)
- pinfo->events[sd].events |= POLL_R_FLAGS;
- if (iod->watched_events & EV_WRITE)
- pinfo->events[sd].events |= POLL_W_FLAGS;
- #ifndef WIN32
- if (iod->watched_events & EV_EXCEPT)
- pinfo->events[sd].events |= POLL_X_FLAGS;
- #endif
- return 1;
- }
- int poll_loop(struct npool *nsp, int msec_timeout) {
- int results_left = 0;
- int event_msecs; /* msecs before an event goes off */
- int combined_msecs;
- int sock_err = 0;
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- assert(msec_timeout >= -1);
- if (nsp->events_pending == 0)
- return 0; /* No need to wait on 0 events ... */
- do {
- struct nevent *nse;
- nsock_log_debug_all("wait for events");
- nse = next_expirable_event(nsp);
- if (!nse)
- event_msecs = -1; /* None of the events specified a timeout */
- else
- event_msecs = MAX(0, TIMEVAL_MSEC_SUBTRACT(nse->timeout, nsock_tod));
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- /* Force a low timeout when capturing packets on systems where
- * the pcap descriptor is not select()able. */
- if (gh_list_count(&nsp->pcap_read_events) > 0)
- if (event_msecs > PCAP_POLL_INTERVAL)
- event_msecs = PCAP_POLL_INTERVAL;
- #endif
- #endif
- /* We cast to unsigned because we want -1 to be very high (since it means no
- * timeout) */
- combined_msecs = MIN((unsigned)event_msecs, (unsigned)msec_timeout);
- #if HAVE_PCAP
- #ifndef PCAP_CAN_DO_SELECT
- /* do non-blocking read on pcap devices that doesn't support select()
- * If there is anything read, just leave this loop. */
- if (pcap_read_on_nonselect(nsp)) {
- /* okay, something was read. */
- } else
- #endif
- #endif
- {
- results_left = Poll(pinfo->events, pinfo->max_fd + 1, combined_msecs);
- if (results_left == -1)
- sock_err = socket_errno();
- }
- gettimeofday(&nsock_tod, NULL); /* Due to poll delay */
- } while (results_left == -1 && sock_err == EINTR); /* repeat only if signal occurred */
- if (results_left == -1 && sock_err != EINTR) {
- nsock_log_error("nsock_loop error %d: %s", sock_err, socket_strerror(sock_err));
- nsp->errnum = sock_err;
- return -1;
- }
- iterate_through_event_lists(nsp);
- return 1;
- }
- /* ---- INTERNAL FUNCTIONS ---- */
- static inline int get_evmask(struct npool *nsp, struct niod *nsi) {
- struct poll_engine_info *pinfo = (struct poll_engine_info *)nsp->engine_data;
- int sd, evmask = EV_NONE;
- POLLFD *pev;
- if (nsi->state != NSIOD_STATE_DELETED
- && nsi->events_pending
- && IOD_PROPGET(nsi, IOD_REGISTERED)) {
- #if HAVE_PCAP
- if (nsi->pcap)
- sd = ((mspcap *)nsi->pcap)->pcap_desc;
- else
- #endif
- sd = nsi->sd;
- assert(sd < pinfo->capacity);
- pev = &pinfo->events[sd];
- if (pev->revents & POLL_R_FLAGS)
- evmask |= EV_READ;
- if (pev->revents & POLL_W_FLAGS)
- evmask |= EV_WRITE;
- if (pev->events && (pev->revents & POLL_X_FLAGS))
- evmask |= (EV_READ | EV_WRITE | EV_EXCEPT);
- }
- return evmask;
- }
- /* Iterate through all the event lists (such as connect_events, read_events,
- * timer_events, etc) and take action for those that have completed (due to
- * timeout, i/o, etc) */
- void iterate_through_event_lists(struct npool *nsp) {
- gh_lnode_t *current, *next, *last;
- last = gh_list_last_elem(&nsp->active_iods);
- for (current = gh_list_first_elem(&nsp->active_iods);
- current != NULL && gh_lnode_prev(current) != last;
- current = next) {
- struct niod *nsi = container_of(current, struct niod, nodeq);
- process_iod_events(nsp, nsi, get_evmask(nsp, nsi));
- next = gh_lnode_next(current);
- if (nsi->state == NSIOD_STATE_DELETED) {
- gh_list_remove(&nsp->active_iods, current);
- gh_list_prepend(&nsp->free_iods, current);
- }
- }
- /* iterate through timers and expired events */
- process_expired_events(nsp);
- }
- #endif /* HAVE_POLL */