--- /dev/null
+/*
+ * IRC - Internet Relay Chat, ircd/engine_select.c
+ * Copyright (C) 2001 Kevin L. Mitchell <klmitch@mit.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 1, or (at your option)
+ * any later version.
+ *
+ * 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/** @file
+ * @brief BSD sockets select() event engine.
+ * @version $Id$
+ */
+#include "config.h"
+
+/* On BSD, define FD_SETSIZE to what we want before including sys/types.h */
+#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__)
+# if !defined(FD_SETSIZE)
+# define FD_SETSIZE ((MAXCONNECTIONS)+4)
+# endif
+#endif
+
+#include "ircd_events.h"
+
+#include "ircd.h"
+#include "ircd_log.h"
+#include "s_debug.h"
+
+/* #include <assert.h> -- Now using assert in ircd_log.h */
+#include <errno.h>
+#include <string.h> /* needed for bzero() on OS X */
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#if FD_SETSIZE < (MAXCONNECTIONS + 4)
+/*
+ * Sanity check
+ *
+ * All operating systems work when MAXCONNECTIONS <= 252.
+ * Most operating systems work when MAXCONNECTIONS <= 1020 and FD_SETSIZE is
+ * updated correctly in the system headers (on BSD systems sys/types.h might
+ * have abruptly redefined it so the check is still done), you might
+ * already need to recompile your kernel.
+ * For larger FD_SETSIZE your mileage may vary (kernel patches may be needed).
+ */
+# error FD_SETSIZE is too small or MAXCONNECTIONS too large.
+#endif
+
+#define SELECT_ERROR_THRESHOLD 20 /**< after 20 select errors, restart */
+#define ERROR_EXPIRE_TIME 3600 /**< expire errors after an hour */
+
+/** Array of active Socket structures, indexed by file descriptor. */
+static struct Socket* sockList[FD_SETSIZE];
+/** Maximum file descriptor currently used. */
+static int highest_fd;
+/** Global read event interest bitmap. */
+static fd_set global_read_set;
+/** Global write event interest bitmap. */
+static fd_set global_write_set;
+
+/** Number of recent errors from select(). */
+static int errors = 0;
+/** Periodic timer to forget errors. */
+static struct Timer clear_error;
+
+/** Decrement the error count (once per hour).
+ * @param[in] ev Expired timer event (ignored).
+ */
+static void
+error_clear(struct Event* ev)
+{
+ if (!--errors) /* remove timer when error count reaches 0 */
+ timer_del(ev_timer(ev));
+}
+
+/** Initialize the select() engine.
+ * @param[in] max_sockets Maximum number of file descriptors to support.
+ * @return Non-zero on success, or zero on failure.
+ */
+static int
+engine_init(int max_sockets)
+{
+ int i;
+
+ if (max_sockets > FD_SETSIZE) { /* too many sockets */
+ log_write(LS_SYSTEM, L_WARNING, 0,
+ "select() engine cannot handle %d sockets (> %d)",
+ max_sockets, FD_SETSIZE);
+ return 0;
+ }
+
+ FD_ZERO(&global_read_set); /* zero the global fd sets */
+ FD_ZERO(&global_write_set);
+
+ for (i = 0; i < FD_SETSIZE; i++) /* zero the sockList */
+ sockList[i] = 0;
+
+ highest_fd = -1; /* No fds in set */
+
+ return 1; /* initialization successful */
+}
+
+/** Figure out what events go with a given state.
+ * @param[in] state %Socket state to consider.
+ * @param[in] events User-specified preferred event set.
+ * @return Actual set of preferred events.
+ */
+static unsigned int
+state_to_events(enum SocketState state, unsigned int events)
+{
+ switch (state) {
+ case SS_CONNECTING: /* connecting socket */
+ return SOCK_EVENT_WRITABLE;
+ break;
+
+ case SS_LISTENING: /* listening socket */
+ case SS_NOTSOCK: /* our signal socket */
+ return SOCK_EVENT_READABLE;
+ break;
+
+ case SS_CONNECTED: case SS_DATAGRAM: case SS_CONNECTDG:
+ return events; /* ordinary socket */
+ break;
+ }
+
+ /*NOTREACHED*/
+ return 0;
+}
+
+/** Set interest events in #global_read_set and #global_write_set as appropriate.
+ * @param[in] fd File descriptor to operate on.
+ * @param[in] clear Set of interest events to clear from socket.
+ * @param[in] set Set of interest events to set on socket.
+ */
+static void
+set_or_clear(int fd, unsigned int clear, unsigned int set)
+{
+ if ((clear ^ set) & SOCK_EVENT_READABLE) { /* readable has changed */
+ if (set & SOCK_EVENT_READABLE) /* it's set */
+ FD_SET(fd, &global_read_set);
+ else /* clear it */
+ FD_CLR(fd, &global_read_set);
+ }
+
+ if ((clear ^ set) & SOCK_EVENT_WRITABLE) { /* writable has changed */
+ if (set & SOCK_EVENT_WRITABLE) /* it's set */
+ FD_SET(fd, &global_write_set);
+ else /* clear it */
+ FD_CLR(fd, &global_write_set);
+ }
+}
+
+/** Add a socket to the event engine.
+ * @param[in] sock Socket to add to engine.
+ * @return Non-zero on success, or zero on error.
+ */
+static int
+engine_add(struct Socket* sock)
+{
+ assert(0 != sock);
+ assert(0 == sockList[s_fd(sock)]);
+
+ /* bounds-check... */
+ if (s_fd(sock) >= FD_SETSIZE) {
+ log_write(LS_SYSTEM, L_ERROR, 0,
+ "Attempt to add socket %d (> %d) to event engine", s_fd(sock),
+ FD_SETSIZE);
+ return 0;
+ }
+
+ sockList[s_fd(sock)] = sock; /* add to list */
+
+ if (s_fd(sock) >= highest_fd) /* update highest_fd */
+ highest_fd = s_fd(sock);
+
+ Debug((DEBUG_ENGINE, "select: Adding socket %d to engine [%p], state %s",
+ s_fd(sock), sock, state_to_name(s_state(sock))));
+
+ /* set the fd set bits */
+ set_or_clear(s_fd(sock), 0, state_to_events(s_state(sock), s_events(sock)));
+
+ return 1; /* success */
+}
+
+/** Handle state transition for a socket.
+ * @param[in] sock Socket changing state.
+ * @param[in] new_state New state for socket.
+ */
+static void
+engine_state(struct Socket* sock, enum SocketState new_state)
+{
+ assert(0 != sock);
+ assert(sock == sockList[s_fd(sock)]);
+
+ Debug((DEBUG_ENGINE, "select: Changing state for socket %p to %s", sock,
+ state_to_name(new_state)));
+
+ /* set the correct events */
+ set_or_clear(s_fd(sock),
+ state_to_events(s_state(sock), s_events(sock)), /* old state */
+ state_to_events(new_state, s_events(sock))); /* new state */
+}
+
+/** Handle change to preferred socket events.
+ * @param[in] sock Socket getting new interest list.
+ * @param[in] new_events New set of interesting events for socket.
+ */
+static void
+engine_events(struct Socket* sock, unsigned int new_events)
+{
+ assert(0 != sock);
+ assert(sock == sockList[s_fd(sock)]);
+
+ Debug((DEBUG_ENGINE, "select: Changing event mask for socket %p to [%s]",
+ sock, sock_flags(new_events)));
+
+ /* set the correct events */
+ set_or_clear(s_fd(sock),
+ state_to_events(s_state(sock), s_events(sock)), /* old events */
+ state_to_events(s_state(sock), new_events)); /* new events */
+}
+
+/** Remove a socket from the event engine.
+ * @param[in] sock Socket being destroyed.
+ */
+static void
+engine_delete(struct Socket* sock)
+{
+ assert(0 != sock);
+ assert(sock == sockList[s_fd(sock)]);
+
+ Debug((DEBUG_ENGINE, "select: Deleting socket %d [%p], state %s", s_fd(sock),
+ sock, state_to_name(s_state(sock))));
+
+ FD_CLR(s_fd(sock), &global_read_set); /* clear event set bits */
+ FD_CLR(s_fd(sock), &global_write_set);
+
+ sockList[s_fd(sock)] = 0; /* zero the socket list entry */
+
+ while (highest_fd > -1 && sockList[highest_fd] == 0) /* update highest_fd */
+ highest_fd--;
+}
+
+/** Run engine event loop.
+ * @param[in] gen Lists of generators of various types.
+ */
+static void
+engine_loop(struct Generators* gen)
+{
+ struct timeval wait;
+ fd_set read_set;
+ fd_set write_set;
+ int nfds;
+ int i;
+ int errcode;
+ socklen_t codesize;
+ struct Socket *sock;
+
+ while (running) {
+ read_set = global_read_set; /* all hail structure copy!! */
+ write_set = global_write_set;
+
+ /* set up the sleep time */
+ wait.tv_sec = timer_next(gen) ? (timer_next(gen) - CurrentTime) : -1;
+ wait.tv_usec = 0;
+
+ Debug((DEBUG_INFO, "select: delay: %Tu (%Tu) %Tu", timer_next(gen),
+ CurrentTime, wait.tv_sec));
+
+ /* check for active files */
+ nfds = select(highest_fd + 1, &read_set, &write_set, 0,
+ wait.tv_sec < 0 ? 0 : &wait);
+
+ CurrentTime = time(0); /* set current time... */
+
+ if (nfds < 0) {
+ if (errno != EINTR) { /* ignore select interrupts */
+ /* Log the select error */
+ log_write(LS_SOCKET, L_ERROR, 0, "select() error: %m");
+ if (!errors++)
+ timer_add(timer_init(&clear_error), error_clear, 0, TT_PERIODIC,
+ ERROR_EXPIRE_TIME);
+ else if (errors > SELECT_ERROR_THRESHOLD) /* too many errors... */
+ server_restart("too many select errors");
+ }
+ /* old code did a sleep(1) here; with usage these days,
+ * that may be too expensive
+ */
+ continue;
+ }
+
+ for (i = 0; nfds && i <= highest_fd; i++) {
+ if (!(sock = sockList[i])) /* skip empty socket elements */
+ continue;
+
+ assert(s_fd(sock) == i);
+
+ gen_ref_inc(sock); /* can't have it going away on us */
+
+ Debug((DEBUG_ENGINE, "select: Checking socket %p (fd %d) state %s, "
+ "events %s", sock, i, state_to_name(s_state(sock)),
+ sock_flags(s_events(sock))));
+
+ if (s_state(sock) != SS_NOTSOCK) {
+ errcode = 0; /* check for errors on socket */
+ codesize = sizeof(errcode);
+ if (getsockopt(i, SOL_SOCKET, SO_ERROR, &errcode, &codesize) < 0)
+ errcode = errno; /* work around Solaris implementation */
+
+ if (errcode) { /* an error occurred; generate an event */
+ Debug((DEBUG_ENGINE, "select: Error %d on fd %d, socket %p", errcode,
+ i, sock));
+ event_generate(ET_ERROR, sock, errcode);
+ gen_ref_dec(sock); /* careful not to leak reference counts */
+ continue;
+ }
+ }
+
+ switch (s_state(sock)) {
+ case SS_CONNECTING:
+ if (FD_ISSET(i, &write_set)) { /* connection completed */
+ Debug((DEBUG_ENGINE, "select: Connection completed"));
+ event_generate(ET_CONNECT, sock, 0);
+ nfds--;
+ continue;
+ }
+ break;
+
+ case SS_LISTENING:
+ if (FD_ISSET(i, &read_set)) { /* connection to be accepted */
+ Debug((DEBUG_ENGINE, "select: Ready for accept"));
+ event_generate(ET_ACCEPT, sock, 0);
+ nfds--;
+ }
+ break;
+
+ case SS_NOTSOCK:
+ if (FD_ISSET(i, &read_set)) { /* data on socket */
+ /* can't peek; it's not a socket */
+ Debug((DEBUG_ENGINE, "select: non-socket readable"));
+ event_generate(ET_READ, sock, 0);
+ nfds--;
+ }
+ break;
+
+ case SS_CONNECTED:
+ if (FD_ISSET(i, &read_set)) { /* data to be read from socket */
+ char c;
+
+ switch (recv(i, &c, 1, MSG_PEEK)) { /* check for EOF */
+ case -1: /* error occurred?!? */
+ if (errno == EAGAIN) {
+ Debug((DEBUG_ENGINE, "select: Resource temporarily "
+ "unavailable?"));
+ continue;
+ }
+ Debug((DEBUG_ENGINE, "select: Uncaught error!"));
+ event_generate(ET_ERROR, sock, errno);
+ break;
+
+ case 0: /* EOF from client */
+ Debug((DEBUG_ENGINE, "select: EOF from client"));
+ event_generate(ET_EOF, sock, 0);
+ break;
+
+ default: /* some data can be read */
+ Debug((DEBUG_ENGINE, "select: Data to be read"));
+ event_generate(ET_READ, sock, 0);
+ break;
+ }
+ }
+ if (FD_ISSET(i, &write_set)) { /* data can be written to socket */
+ Debug((DEBUG_ENGINE, "select: Data can be written"));
+ event_generate(ET_WRITE, sock, 0);
+ }
+ if (FD_ISSET(i, &read_set) || FD_ISSET(i, &write_set))
+ nfds--;
+ break;
+
+ case SS_DATAGRAM: case SS_CONNECTDG:
+ if (FD_ISSET(i, &read_set)) { /* data to be read from socket */
+ Debug((DEBUG_ENGINE, "select: Datagram to be read"));
+ event_generate(ET_READ, sock, 0);
+ }
+ if (FD_ISSET(i, &write_set)) { /* data can be written to socket */
+ Debug((DEBUG_ENGINE, "select: Datagram can be written"));
+ event_generate(ET_WRITE, sock, 0);
+ }
+ if (FD_ISSET(i, &read_set) || FD_ISSET(i, &write_set))
+ nfds--;
+ break;
+ }
+
+ gen_ref_dec(sock); /* we're done with it */
+ }
+
+ timer_run(); /* execute any pending timers */
+ }
+}
+
+/** Descriptor for select() event engine. */
+struct Engine engine_select = {
+ "select()", /* Engine name */
+ engine_init, /* Engine initialization function */
+ 0, /* Engine signal registration function (none) */
+ engine_add, /* Engine socket registration function */
+ engine_state, /* Engine socket state change function */
+ engine_events, /* Engine socket events mask function */
+ engine_delete, /* Engine socket deletion function */
+ engine_loop /* Core engine event loop */
+};
projects / ircu2.10.12-pk.git / blobdiff