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-rw-r--r--nsock/src/engine_select.c395
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diff --git a/nsock/src/engine_select.c b/nsock/src/engine_select.c
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+/***************************************************************************
+ * engine_select.c -- select(2) based IO engine. *
+ * *
+ ***********************IMPORTANT NSOCK LICENSE TERMS***********************
+ *
+ * The nsock parallel socket event library is (C) 1999-2023 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
+#include <sys/select.h>
+#endif
+
+#include <errno.h>
+
+#include "nsock_internal.h"
+#include "nsock_log.h"
+
+#if HAVE_PCAP
+#include "nsock_pcap.h"
+#endif
+
+extern struct io_operations posix_io_operations;
+
+
+/* --- ENGINE INTERFACE PROTOTYPES --- */
+static int select_init(struct npool *nsp);
+static void select_destroy(struct npool *nsp);
+static int select_iod_register(struct npool *nsp, struct niod *iod, struct nevent *nse, int ev);
+static int select_iod_unregister(struct npool *nsp, struct niod *iod);
+static int select_iod_modify(struct npool *nsp, struct niod *iod, struct nevent *nse, int ev_set, int ev_clr);
+static int select_loop(struct npool *nsp, int msec_timeout);
+
+
+/* ---- ENGINE DEFINITION ---- */
+struct io_engine engine_select = {
+ "select",
+ select_init,
+ select_destroy,
+ select_iod_register,
+ select_iod_unregister,
+ select_iod_modify,
+ select_loop,
+ &posix_io_operations
+};
+
+
+/* --- INTERNAL PROTOTYPES --- */
+static void iterate_through_event_lists(struct npool *nsp);
+
+/* defined in nsock_core.c */
+void process_event(struct npool *nsp, gh_list_t *evlist, struct nevent *nse, int ev);
+void process_iod_events(struct npool *nsp, struct niod *nsi, 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 select_engine_info {
+ /* Descriptors which have pending READ events */
+ fd_set fds_master_r;
+
+ /* Descriptors we are trying to WRITE to */
+ fd_set fds_master_w;
+
+ /* Looking for exceptional events -- used with connect */
+ fd_set fds_master_x;
+
+ /* For keeping track of the select results */
+ fd_set fds_results_r, fds_results_w, fds_results_x;
+
+ /* The highest sd we have set in any of our fd_set's (max_sd + 1 is used in
+ * select() calls). Note that it can be -1, when there are no valid sockets */
+ int max_sd;
+};
+
+
+int select_init(struct npool *nsp) {
+ struct select_engine_info *sinfo;
+
+ sinfo = (struct select_engine_info *)safe_malloc(sizeof(struct select_engine_info));
+
+ FD_ZERO(&sinfo->fds_master_r);
+ FD_ZERO(&sinfo->fds_master_w);
+ FD_ZERO(&sinfo->fds_master_x);
+
+ sinfo->max_sd = -1;
+
+ nsp->engine_data = (void *)sinfo;
+
+ return 1;
+}
+
+void select_destroy(struct npool *nsp) {
+ assert(nsp->engine_data != NULL);
+ free(nsp->engine_data);
+}
+
+int select_iod_register(struct npool *nsp, struct niod *iod, struct nevent *nse, int ev) {
+ assert(!IOD_PROPGET(iod, IOD_REGISTERED));
+
+ iod->watched_events = ev;
+ select_iod_modify(nsp, iod, nse, ev, EV_NONE);
+ IOD_PROPSET(iod, IOD_REGISTERED);
+ return 1;
+}
+
+int select_iod_unregister(struct npool *nsp, struct niod *iod) {
+ struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
+
+ 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)) {
+#if HAVE_PCAP
+ if (iod->pcap) {
+ int sd = ((mspcap *)iod->pcap)->pcap_desc;
+ if (sd >= 0) {
+ checked_fd_clr(sd, &sinfo->fds_master_r);
+ checked_fd_clr(sd, &sinfo->fds_results_r);
+ }
+ } else
+#endif
+ {
+ checked_fd_clr(iod->sd, &sinfo->fds_master_r);
+ checked_fd_clr(iod->sd, &sinfo->fds_master_w);
+ checked_fd_clr(iod->sd, &sinfo->fds_master_x);
+ checked_fd_clr(iod->sd, &sinfo->fds_results_r);
+ checked_fd_clr(iod->sd, &sinfo->fds_results_w);
+ checked_fd_clr(iod->sd, &sinfo->fds_results_x);
+ }
+
+ if (sinfo->max_sd == iod->sd)
+ sinfo->max_sd--;
+
+ IOD_PROPCLR(iod, IOD_REGISTERED);
+ }
+ return 1;
+}
+
+int select_iod_modify(struct npool *nsp, struct niod *iod, struct nevent *nse, int ev_set, int ev_clr) {
+ int sd;
+ struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
+
+ assert((ev_set & ev_clr) == 0);
+
+ iod->watched_events |= ev_set;
+ iod->watched_events &= ~ev_clr;
+
+ ev_set |= EV_EXCEPT;
+ ev_clr &= ~EV_EXCEPT;
+
+ sd = nsock_iod_get_sd(iod);
+
+ /* -- set events -- */
+ if (ev_set & EV_READ)
+ checked_fd_set(sd, &sinfo->fds_master_r);
+
+ if (ev_set & EV_WRITE)
+ checked_fd_set(sd, &sinfo->fds_master_w);
+
+ if (ev_set & EV_EXCEPT)
+ checked_fd_set(sd, &sinfo->fds_master_x);
+
+ /* -- clear events -- */
+ if (ev_clr & EV_READ)
+ checked_fd_clr(sd, &sinfo->fds_master_r);
+
+ if (ev_clr & EV_WRITE)
+ checked_fd_clr(sd, &sinfo->fds_master_w);
+
+ if (ev_clr & EV_EXCEPT)
+ checked_fd_clr(sd, &sinfo->fds_master_x);
+
+
+ /* -- update max_sd -- */
+ if (ev_set != EV_NONE)
+ sinfo->max_sd = MAX(sinfo->max_sd, sd);
+ else if (ev_clr != EV_NONE && iod->events_pending == 1 && (sinfo->max_sd == sd))
+ sinfo->max_sd--;
+
+ return 1;
+}
+
+int select_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 timeval select_tv;
+ struct timeval *select_tv_p;
+ struct select_engine_info *sinfo = (struct select_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))
+ 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);
+
+ /* Set up the timeval pointer we will give to select() */
+ memset(&select_tv, 0, sizeof(select_tv));
+ if (combined_msecs > 0) {
+ select_tv.tv_sec = combined_msecs / 1000;
+ select_tv.tv_usec = (combined_msecs % 1000) * 1000;
+ select_tv_p = &select_tv;
+ } else if (combined_msecs == 0) {
+ /* we want the tv_sec and tv_usec to be zero but they already are from bzero */
+ select_tv_p = &select_tv;
+ } else {
+ assert(combined_msecs == -1);
+ select_tv_p = NULL;
+ }
+
+#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
+ {
+ /* Set up the descriptors for select */
+ sinfo->fds_results_r = sinfo->fds_master_r;
+ sinfo->fds_results_w = sinfo->fds_master_w;
+ sinfo->fds_results_x = sinfo->fds_master_x;
+
+ results_left = fselect(sinfo->max_sd + 1, &sinfo->fds_results_r,
+ &sinfo->fds_results_w, &sinfo->fds_results_x, select_tv_p);
+
+ if (results_left == -1)
+ sock_err = socket_errno();
+ }
+
+ gettimeofday(&nsock_tod, NULL); /* Due to select 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(const struct npool *nsp, const struct niod *nsi) {
+ struct select_engine_info *sinfo = (struct select_engine_info *)nsp->engine_data;
+ int sd, evmask;
+
+ evmask = EV_NONE;
+
+#if HAVE_PCAP
+#ifndef PCAP_CAN_DO_SELECT
+ if (nsi->pcap) {
+ /* Always assume readable for a non-blocking read. We can't check checked_fd_isset
+ because we don't have a pcap_desc. */
+ evmask |= EV_READ;
+ return evmask;
+ }
+#endif
+#endif
+
+#if HAVE_PCAP
+ if (nsi->pcap)
+ sd = ((mspcap *)nsi->pcap)->pcap_desc;
+ else
+#endif
+ sd = nsi->sd;
+
+ assert(sd >= 0);
+
+ if (checked_fd_isset(sd, &sinfo->fds_results_r))
+ evmask |= EV_READ;
+ if (checked_fd_isset(sd, &sinfo->fds_results_w))
+ evmask |= EV_WRITE;
+ if (checked_fd_isset(sd, &sinfo->fds_results_x))
+ 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);
+
+ if (nsi->state != NSIOD_STATE_DELETED && nsi->events_pending)
+ 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);
+}
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