Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 1 | /* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu> |
| 5 | * Copyright 2007-2012 Niels Provos and Nick Mathewson |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * 3. The name of the author may not be used to endorse or promote products |
| 16 | * derived from this software without specific prior written permission. |
| 17 | * |
| 18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 28 | */ |
| 29 | #include "event2/event-config.h" |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 30 | #include "evconfig-private.h" |
| 31 | |
| 32 | #ifdef EVENT__HAVE_SELECT |
| 33 | |
| 34 | #ifdef __APPLE__ |
| 35 | /* Apple wants us to define this if we might ever pass more than |
| 36 | * FD_SETSIZE bits to select(). */ |
| 37 | #define _DARWIN_UNLIMITED_SELECT |
| 38 | #endif |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 39 | |
| 40 | #include <sys/types.h> |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 41 | #ifdef EVENT__HAVE_SYS_TIME_H |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 42 | #include <sys/time.h> |
| 43 | #endif |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 44 | #ifdef EVENT__HAVE_SYS_SELECT_H |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 45 | #include <sys/select.h> |
| 46 | #endif |
| 47 | #include <sys/queue.h> |
| 48 | #include <signal.h> |
| 49 | #include <stdio.h> |
| 50 | #include <stdlib.h> |
| 51 | #include <string.h> |
| 52 | #include <unistd.h> |
| 53 | #include <errno.h> |
| 54 | |
| 55 | #include "event-internal.h" |
| 56 | #include "evsignal-internal.h" |
| 57 | #include "event2/thread.h" |
| 58 | #include "evthread-internal.h" |
| 59 | #include "log-internal.h" |
| 60 | #include "evmap-internal.h" |
| 61 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 62 | #ifndef EVENT__HAVE_FD_MASK |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 63 | /* This type is mandatory, but Android doesn't define it. */ |
| 64 | typedef unsigned long fd_mask; |
| 65 | #endif |
| 66 | |
| 67 | #ifndef NFDBITS |
| 68 | #define NFDBITS (sizeof(fd_mask)*8) |
| 69 | #endif |
| 70 | |
| 71 | /* Divide positive x by y, rounding up. */ |
| 72 | #define DIV_ROUNDUP(x, y) (((x)+((y)-1))/(y)) |
| 73 | |
| 74 | /* How many bytes to allocate for N fds? */ |
| 75 | #define SELECT_ALLOC_SIZE(n) \ |
| 76 | (DIV_ROUNDUP(n, NFDBITS) * sizeof(fd_mask)) |
| 77 | |
| 78 | struct selectop { |
| 79 | int event_fds; /* Highest fd in fd set */ |
| 80 | int event_fdsz; |
| 81 | int resize_out_sets; |
| 82 | fd_set *event_readset_in; |
| 83 | fd_set *event_writeset_in; |
| 84 | fd_set *event_readset_out; |
| 85 | fd_set *event_writeset_out; |
| 86 | }; |
| 87 | |
| 88 | static void *select_init(struct event_base *); |
| 89 | static int select_add(struct event_base *, int, short old, short events, void*); |
| 90 | static int select_del(struct event_base *, int, short old, short events, void*); |
| 91 | static int select_dispatch(struct event_base *, struct timeval *); |
| 92 | static void select_dealloc(struct event_base *); |
| 93 | |
| 94 | const struct eventop selectops = { |
| 95 | "select", |
| 96 | select_init, |
| 97 | select_add, |
| 98 | select_del, |
| 99 | select_dispatch, |
| 100 | select_dealloc, |
Haibo Huang | f0077b8 | 2020-07-10 20:21:19 -0700 | [diff] [blame] | 101 | 1, /* need_reinit. */ |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 102 | EV_FEATURE_FDS, |
| 103 | 0, |
| 104 | }; |
| 105 | |
| 106 | static int select_resize(struct selectop *sop, int fdsz); |
| 107 | static void select_free_selectop(struct selectop *sop); |
| 108 | |
| 109 | static void * |
| 110 | select_init(struct event_base *base) |
| 111 | { |
| 112 | struct selectop *sop; |
| 113 | |
| 114 | if (!(sop = mm_calloc(1, sizeof(struct selectop)))) |
| 115 | return (NULL); |
| 116 | |
| 117 | if (select_resize(sop, SELECT_ALLOC_SIZE(32 + 1))) { |
| 118 | select_free_selectop(sop); |
| 119 | return (NULL); |
| 120 | } |
| 121 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 122 | evsig_init_(base); |
| 123 | |
| 124 | evutil_weakrand_seed_(&base->weakrand_seed, 0); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 125 | |
| 126 | return (sop); |
| 127 | } |
| 128 | |
| 129 | #ifdef CHECK_INVARIANTS |
| 130 | static void |
| 131 | check_selectop(struct selectop *sop) |
| 132 | { |
| 133 | /* nothing to be done here */ |
| 134 | } |
| 135 | #else |
| 136 | #define check_selectop(sop) do { (void) sop; } while (0) |
| 137 | #endif |
| 138 | |
| 139 | static int |
| 140 | select_dispatch(struct event_base *base, struct timeval *tv) |
| 141 | { |
| 142 | int res=0, i, j, nfds; |
| 143 | struct selectop *sop = base->evbase; |
| 144 | |
| 145 | check_selectop(sop); |
| 146 | if (sop->resize_out_sets) { |
| 147 | fd_set *readset_out=NULL, *writeset_out=NULL; |
| 148 | size_t sz = sop->event_fdsz; |
| 149 | if (!(readset_out = mm_realloc(sop->event_readset_out, sz))) |
| 150 | return (-1); |
| 151 | sop->event_readset_out = readset_out; |
| 152 | if (!(writeset_out = mm_realloc(sop->event_writeset_out, sz))) { |
| 153 | /* We don't free readset_out here, since it was |
| 154 | * already successfully reallocated. The next time |
| 155 | * we call select_dispatch, the realloc will be a |
| 156 | * no-op. */ |
| 157 | return (-1); |
| 158 | } |
| 159 | sop->event_writeset_out = writeset_out; |
| 160 | sop->resize_out_sets = 0; |
| 161 | } |
| 162 | |
| 163 | memcpy(sop->event_readset_out, sop->event_readset_in, |
| 164 | sop->event_fdsz); |
| 165 | memcpy(sop->event_writeset_out, sop->event_writeset_in, |
| 166 | sop->event_fdsz); |
| 167 | |
| 168 | nfds = sop->event_fds+1; |
| 169 | |
| 170 | EVBASE_RELEASE_LOCK(base, th_base_lock); |
| 171 | |
| 172 | res = select(nfds, sop->event_readset_out, |
| 173 | sop->event_writeset_out, NULL, tv); |
| 174 | |
| 175 | EVBASE_ACQUIRE_LOCK(base, th_base_lock); |
| 176 | |
| 177 | check_selectop(sop); |
| 178 | |
| 179 | if (res == -1) { |
| 180 | if (errno != EINTR) { |
| 181 | event_warn("select"); |
| 182 | return (-1); |
| 183 | } |
| 184 | |
| 185 | return (0); |
| 186 | } |
| 187 | |
| 188 | event_debug(("%s: select reports %d", __func__, res)); |
| 189 | |
| 190 | check_selectop(sop); |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 191 | i = evutil_weakrand_range_(&base->weakrand_seed, nfds); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 192 | for (j = 0; j < nfds; ++j) { |
| 193 | if (++i >= nfds) |
| 194 | i = 0; |
| 195 | res = 0; |
| 196 | if (FD_ISSET(i, sop->event_readset_out)) |
| 197 | res |= EV_READ; |
| 198 | if (FD_ISSET(i, sop->event_writeset_out)) |
| 199 | res |= EV_WRITE; |
| 200 | |
| 201 | if (res == 0) |
| 202 | continue; |
| 203 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 204 | evmap_io_active_(base, i, res); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 205 | } |
| 206 | check_selectop(sop); |
| 207 | |
| 208 | return (0); |
| 209 | } |
| 210 | |
| 211 | static int |
| 212 | select_resize(struct selectop *sop, int fdsz) |
| 213 | { |
| 214 | fd_set *readset_in = NULL; |
| 215 | fd_set *writeset_in = NULL; |
| 216 | |
| 217 | if (sop->event_readset_in) |
| 218 | check_selectop(sop); |
| 219 | |
| 220 | if ((readset_in = mm_realloc(sop->event_readset_in, fdsz)) == NULL) |
| 221 | goto error; |
| 222 | sop->event_readset_in = readset_in; |
| 223 | if ((writeset_in = mm_realloc(sop->event_writeset_in, fdsz)) == NULL) { |
| 224 | /* Note that this will leave event_readset_in expanded. |
| 225 | * That's okay; we wouldn't want to free it, since that would |
| 226 | * change the semantics of select_resize from "expand the |
| 227 | * readset_in and writeset_in, or return -1" to "expand the |
| 228 | * *set_in members, or trash them and return -1." |
| 229 | */ |
| 230 | goto error; |
| 231 | } |
| 232 | sop->event_writeset_in = writeset_in; |
| 233 | sop->resize_out_sets = 1; |
| 234 | |
| 235 | memset((char *)sop->event_readset_in + sop->event_fdsz, 0, |
| 236 | fdsz - sop->event_fdsz); |
| 237 | memset((char *)sop->event_writeset_in + sop->event_fdsz, 0, |
| 238 | fdsz - sop->event_fdsz); |
| 239 | |
| 240 | sop->event_fdsz = fdsz; |
| 241 | check_selectop(sop); |
| 242 | |
| 243 | return (0); |
| 244 | |
| 245 | error: |
| 246 | event_warn("malloc"); |
| 247 | return (-1); |
| 248 | } |
| 249 | |
| 250 | |
| 251 | static int |
| 252 | select_add(struct event_base *base, int fd, short old, short events, void *p) |
| 253 | { |
| 254 | struct selectop *sop = base->evbase; |
| 255 | (void) p; |
| 256 | |
| 257 | EVUTIL_ASSERT((events & EV_SIGNAL) == 0); |
| 258 | check_selectop(sop); |
| 259 | /* |
| 260 | * Keep track of the highest fd, so that we can calculate the size |
| 261 | * of the fd_sets for select(2) |
| 262 | */ |
| 263 | if (sop->event_fds < fd) { |
| 264 | int fdsz = sop->event_fdsz; |
| 265 | |
| 266 | if (fdsz < (int)sizeof(fd_mask)) |
| 267 | fdsz = (int)sizeof(fd_mask); |
| 268 | |
| 269 | /* In theory we should worry about overflow here. In |
| 270 | * reality, though, the highest fd on a unixy system will |
| 271 | * not overflow here. XXXX */ |
| 272 | while (fdsz < (int) SELECT_ALLOC_SIZE(fd + 1)) |
| 273 | fdsz *= 2; |
| 274 | |
| 275 | if (fdsz != sop->event_fdsz) { |
| 276 | if (select_resize(sop, fdsz)) { |
| 277 | check_selectop(sop); |
| 278 | return (-1); |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | sop->event_fds = fd; |
| 283 | } |
| 284 | |
| 285 | if (events & EV_READ) |
| 286 | FD_SET(fd, sop->event_readset_in); |
| 287 | if (events & EV_WRITE) |
| 288 | FD_SET(fd, sop->event_writeset_in); |
| 289 | check_selectop(sop); |
| 290 | |
| 291 | return (0); |
| 292 | } |
| 293 | |
| 294 | /* |
| 295 | * Nothing to be done here. |
| 296 | */ |
| 297 | |
| 298 | static int |
| 299 | select_del(struct event_base *base, int fd, short old, short events, void *p) |
| 300 | { |
| 301 | struct selectop *sop = base->evbase; |
| 302 | (void)p; |
| 303 | |
| 304 | EVUTIL_ASSERT((events & EV_SIGNAL) == 0); |
| 305 | check_selectop(sop); |
| 306 | |
| 307 | if (sop->event_fds < fd) { |
| 308 | check_selectop(sop); |
| 309 | return (0); |
| 310 | } |
| 311 | |
| 312 | if (events & EV_READ) |
| 313 | FD_CLR(fd, sop->event_readset_in); |
| 314 | |
| 315 | if (events & EV_WRITE) |
| 316 | FD_CLR(fd, sop->event_writeset_in); |
| 317 | |
| 318 | check_selectop(sop); |
| 319 | return (0); |
| 320 | } |
| 321 | |
| 322 | static void |
| 323 | select_free_selectop(struct selectop *sop) |
| 324 | { |
| 325 | if (sop->event_readset_in) |
| 326 | mm_free(sop->event_readset_in); |
| 327 | if (sop->event_writeset_in) |
| 328 | mm_free(sop->event_writeset_in); |
| 329 | if (sop->event_readset_out) |
| 330 | mm_free(sop->event_readset_out); |
| 331 | if (sop->event_writeset_out) |
| 332 | mm_free(sop->event_writeset_out); |
| 333 | |
| 334 | memset(sop, 0, sizeof(struct selectop)); |
| 335 | mm_free(sop); |
| 336 | } |
| 337 | |
| 338 | static void |
| 339 | select_dealloc(struct event_base *base) |
| 340 | { |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 341 | evsig_dealloc_(base); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 342 | |
| 343 | select_free_selectop(base->evbase); |
| 344 | } |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 345 | |
| 346 | #endif /* EVENT__HAVE_SELECT */ |