X-Git-Url: https://arthur.barton.de/cgi-bin/gitweb.cgi?p=netatalk.git;a=blobdiff_plain;f=libevent%2Fselect.c;fp=libevent%2Fselect.c;h=527462ca26ba167533cbaf48651e969c25f9bfad;hp=0000000000000000000000000000000000000000;hb=9c8a21a5a13808bab520bd257b3d0a6fe16c6b07;hpb=4cafdfb9f307e9cc6131a79d09011ef09f3b8f20 diff --git a/libevent/select.c b/libevent/select.c new file mode 100644 index 00000000..527462ca --- /dev/null +++ b/libevent/select.c @@ -0,0 +1,311 @@ +/* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */ + +/* + * Copyright 2000-2007 Niels Provos + * Copyright 2007-2010 Niels Provos and Nick Mathewson + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#include "event2/event-config.h" + +#include +#ifdef _EVENT_HAVE_SYS_TIME_H +#include +#endif +#ifdef _EVENT_HAVE_SYS_SELECT_H +#include +#endif +#include +#include +#include +#include +#include +#include +#include + +#include "event-internal.h" +#include "evsignal-internal.h" +#include "event2/thread.h" +#include "evthread-internal.h" +#include "log-internal.h" +#include "evmap-internal.h" + +#ifndef howmany +#define howmany(x, y) (((x)+((y)-1))/(y)) +#endif + +#ifndef _EVENT_HAVE_FD_MASK +/* This type is mandatory, but Android doesn't define it. */ +#undef NFDBITS +#define NFDBITS (sizeof(long)*8) +typedef unsigned long fd_mask; +#endif + +struct selectop { + int event_fds; /* Highest fd in fd set */ + int event_fdsz; + int resize_out_sets; + fd_set *event_readset_in; + fd_set *event_writeset_in; + fd_set *event_readset_out; + fd_set *event_writeset_out; +}; + +static void *select_init(struct event_base *); +static int select_add(struct event_base *, int, short old, short events, void*); +static int select_del(struct event_base *, int, short old, short events, void*); +static int select_dispatch(struct event_base *, struct timeval *); +static void select_dealloc(struct event_base *); + +const struct eventop selectops = { + "select", + select_init, + select_add, + select_del, + select_dispatch, + select_dealloc, + 0, /* doesn't need reinit. */ + EV_FEATURE_FDS, + 0, +}; + +static int select_resize(struct selectop *sop, int fdsz); + +static void * +select_init(struct event_base *base) +{ + struct selectop *sop; + + if (!(sop = mm_calloc(1, sizeof(struct selectop)))) + return (NULL); + + select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask)); + + evsig_init(base); + + return (sop); +} + +#ifdef CHECK_INVARIANTS +static void +check_selectop(struct selectop *sop) +{ + /* nothing to be done here */ +} +#else +#define check_selectop(sop) do { (void) sop; } while (0) +#endif + +static int +select_dispatch(struct event_base *base, struct timeval *tv) +{ + int res=0, i, j, nfds; + struct selectop *sop = base->evbase; + + check_selectop(sop); + if (sop->resize_out_sets) { + fd_set *readset_out=NULL, *writeset_out=NULL; + size_t sz = sop->event_fdsz; + if (!(readset_out = mm_realloc(sop->event_readset_out, sz))) + return (-1); + if (!(writeset_out = mm_realloc(sop->event_writeset_out, sz))) { + mm_free(readset_out); + return (-1); + } + sop->event_readset_out = readset_out; + sop->event_writeset_out = writeset_out; + sop->resize_out_sets = 0; + } + + memcpy(sop->event_readset_out, sop->event_readset_in, + sop->event_fdsz); + memcpy(sop->event_writeset_out, sop->event_writeset_in, + sop->event_fdsz); + + nfds = sop->event_fds+1; + + EVBASE_RELEASE_LOCK(base, th_base_lock); + + res = select(nfds, sop->event_readset_out, + sop->event_writeset_out, NULL, tv); + + EVBASE_ACQUIRE_LOCK(base, th_base_lock); + + check_selectop(sop); + + if (res == -1) { + if (errno != EINTR) { + event_warn("select"); + return (-1); + } + + return (0); + } + + event_debug(("%s: select reports %d", __func__, res)); + + check_selectop(sop); + i = random() % (nfds+1); + for (j = 0; j <= nfds; ++j) { + if (++i >= nfds+1) + i = 0; + res = 0; + if (FD_ISSET(i, sop->event_readset_out)) + res |= EV_READ; + if (FD_ISSET(i, sop->event_writeset_out)) + res |= EV_WRITE; + + if (res == 0) + continue; + + evmap_io_active(base, i, res); + } + check_selectop(sop); + + return (0); +} + + +static int +select_resize(struct selectop *sop, int fdsz) +{ + fd_set *readset_in = NULL; + fd_set *writeset_in = NULL; + + if (sop->event_readset_in) + check_selectop(sop); + + if ((readset_in = mm_realloc(sop->event_readset_in, fdsz)) == NULL) + goto error; + sop->event_readset_in = readset_in; + if ((writeset_in = mm_realloc(sop->event_writeset_in, fdsz)) == NULL) + goto error; + sop->event_writeset_in = writeset_in; + sop->resize_out_sets = 1; + + memset((char *)sop->event_readset_in + sop->event_fdsz, 0, + fdsz - sop->event_fdsz); + memset((char *)sop->event_writeset_in + sop->event_fdsz, 0, + fdsz - sop->event_fdsz); + + sop->event_fdsz = fdsz; + check_selectop(sop); + + return (0); + + error: + event_warn("malloc"); + return (-1); +} + + +static int +select_add(struct event_base *base, int fd, short old, short events, void *p) +{ + struct selectop *sop = base->evbase; + (void) p; + + EVUTIL_ASSERT((events & EV_SIGNAL) == 0); + check_selectop(sop); + /* + * Keep track of the highest fd, so that we can calculate the size + * of the fd_sets for select(2) + */ + if (sop->event_fds < fd) { + int fdsz = sop->event_fdsz; + + if (fdsz < (int)sizeof(fd_mask)) + fdsz = (int)sizeof(fd_mask); + + /* In theory we should worry about overflow here. In + * reality, though, the highest fd on a unixy system will + * not overflow here. XXXX */ + while (fdsz < + (int) (howmany(fd + 1, NFDBITS) * sizeof(fd_mask))) + fdsz *= 2; + + if (fdsz != sop->event_fdsz) { + if (select_resize(sop, fdsz)) { + check_selectop(sop); + return (-1); + } + } + + sop->event_fds = fd; + } + + if (events & EV_READ) + FD_SET(fd, sop->event_readset_in); + if (events & EV_WRITE) + FD_SET(fd, sop->event_writeset_in); + check_selectop(sop); + + return (0); +} + +/* + * Nothing to be done here. + */ + +static int +select_del(struct event_base *base, int fd, short old, short events, void *p) +{ + struct selectop *sop = base->evbase; + (void)p; + + EVUTIL_ASSERT((events & EV_SIGNAL) == 0); + check_selectop(sop); + + if (sop->event_fds < fd) { + check_selectop(sop); + return (0); + } + + if (events & EV_READ) + FD_CLR(fd, sop->event_readset_in); + + if (events & EV_WRITE) + FD_CLR(fd, sop->event_writeset_in); + + check_selectop(sop); + return (0); +} + +static void +select_dealloc(struct event_base *base) +{ + struct selectop *sop = base->evbase; + + evsig_dealloc(base); + if (sop->event_readset_in) + mm_free(sop->event_readset_in); + if (sop->event_writeset_in) + mm_free(sop->event_writeset_in); + if (sop->event_readset_out) + mm_free(sop->event_readset_out); + if (sop->event_writeset_out) + mm_free(sop->event_writeset_out); + + memset(sop, 0, sizeof(struct selectop)); + mm_free(sop); +}