/*************************************************************************** * engine_poll.c -- poll(2) based IO engine. * * * ***********************IMPORTANT NSOCK LICENSE TERMS*********************** * * The nsock parallel socket event library is (C) 1999-2024 Nmap Software 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, Nmap Software LLC may be willing to sell alternative * licenses (contact sales@nmap.com ). * * As a special exception to the GPL terms, Nmap Software 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. * * If you received these files with a written license agreement stating terms * other than the (GPL) terms above, then that alternative license agreement * takes precedence over this comment. * * 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. This also * allows you to audit the software for security holes. * * Source code also allows you to port Nmap to new platforms, fix bugs, and add * new features. You are highly encouraged to send your changes to the * dev@nmap.org mailing list for possible incorporation into the main * distribution. By sending these changes to Fyodor or one of the Insecure.Org * development mailing lists, or checking them into the Nmap source code * repository, it is understood (unless you specify otherwise) that you are * offering the Nmap Project (Nmap Software LLC) the 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 for other Free Software projects (such as KDE * and NASM). We also occasionally relicense the code to third parties as * discussed above. If you wish to specify special license conditions of your * contributions, just say so when you send them. * * 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 #ifndef WIN32 #include #else #include #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 */ extern struct io_operations posix_io_operations; /* --- 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, struct nevent *nse, int ev); static int poll_iod_unregister(struct npool *nsp, struct niod *iod); static int poll_iod_modify(struct npool *nsp, struct niod *iod, struct nevent *nse, 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, &posix_io_operations }; /* --- 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, struct nevent *nse, 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, struct nevent *nse, 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; 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) { #ifdef WIN32 for (int i = 0; sock_err != EINVAL || i <= pinfo->max_fd; i++) { if (sock_err != EINVAL || pinfo->events[i].fd != -1) { #endif nsock_log_error("nsock_loop error %d: %s", sock_err, socket_strerror(sock_err)); nsp->errnum = sock_err; return -1; #ifdef WIN32 } } #endif } 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_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 */