X-Git-Url: http://git.pk910.de/?p=ircu2.10.12-pk.git;a=blobdiff_plain;f=ircd%2Fengine_select.c;fp=ircd%2Fengine_select.c;h=436f10baa1122b86007990d1c0fc922a919879e2;hp=0000000000000000000000000000000000000000;hb=0400a5a6479398d82526785c18c0df8bc8b92dce;hpb=d17e10da972ce5776c60b4c317267c6abe0e1ead diff --git a/ircd/engine_select.c b/ircd/engine_select.c new file mode 100644 index 0000000..436f10b --- /dev/null +++ b/ircd/engine_select.c @@ -0,0 +1,423 @@ +/* + * IRC - Internet Relay Chat, ircd/engine_select.c + * Copyright (C) 2001 Kevin L. Mitchell + * + * 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 -- Now using assert in ircd_log.h */ +#include +#include /* needed for bzero() on OS X */ +#include +#include +#include +#include +#include + +#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 */ +};