1/* $NetBSD: ev_files.c,v 1.1.1.2 2012/09/09 16:08:03 christos Exp $ */ 2 3/* 4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (c) 1995-1999 by Internet Software Consortium 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20/* ev_files.c - implement asynch file IO for the eventlib 21 * vix 11sep95 [initial] 22 */ 23 24#if !defined(LINT) && !defined(CODECENTER) 25static const char rcsid[] = "Id: ev_files.c,v 1.8 2005/07/28 06:51:48 marka Exp "; 26#endif 27 28#include "port_before.h" 29#include "fd_setsize.h" 30 31#include <sys/types.h> 32#include <sys/time.h> 33#include <sys/ioctl.h> 34 35#include <errno.h> 36#include <fcntl.h> 37#include <unistd.h> 38 39#include <isc/eventlib.h> 40#include "eventlib_p.h" 41 42#include "port_after.h" 43 44static evFile *FindFD(const evContext_p *ctx, int fd, int eventmask); 45 46int 47evSelectFD(evContext opaqueCtx, 48 int fd, 49 int eventmask, 50 evFileFunc func, 51 void *uap, 52 evFileID *opaqueID 53) { 54 evContext_p *ctx = opaqueCtx.opaque; 55 evFile *id; 56 int mode; 57 58 evPrintf(ctx, 1, 59 "evSelectFD(ctx %p, fd %d, mask 0x%x, func %p, uap %p)\n", 60 ctx, fd, eventmask, func, uap); 61 if (eventmask == 0 || (eventmask & ~EV_MASK_ALL) != 0) 62 EV_ERR(EINVAL); 63#ifndef USE_POLL 64 if (fd > ctx->highestFD) 65 EV_ERR(EINVAL); 66#endif 67 OK(mode = fcntl(fd, F_GETFL, NULL)); /*%< side effect: validate fd. */ 68 /* 69 * The first time we touch a file descriptor, we need to check to see 70 * if the application already had it in O_NONBLOCK mode and if so, all 71 * of our deselect()'s have to leave it in O_NONBLOCK. If not, then 72 * all but our last deselect() has to leave it in O_NONBLOCK. 73 */ 74#ifdef USE_POLL 75 /* Make sure both ctx->pollfds[] and ctx->fdTable[] are large enough */ 76 if (fd >= ctx->maxnfds && evPollfdRealloc(ctx, 1, fd) != 0) 77 EV_ERR(ENOMEM); 78#endif /* USE_POLL */ 79 id = FindFD(ctx, fd, EV_MASK_ALL); 80 if (id == NULL) { 81 if (mode & PORT_NONBLOCK) 82 FD_SET(fd, &ctx->nonblockBefore); 83 else { 84#ifdef USE_FIONBIO_IOCTL 85 int on = 1; 86 OK(ioctl(fd, FIONBIO, (char *)&on)); 87#else 88 OK(fcntl(fd, F_SETFL, mode | PORT_NONBLOCK)); 89#endif 90 FD_CLR(fd, &ctx->nonblockBefore); 91 } 92 } 93 94 /* 95 * If this descriptor is already in use, search for it again to see 96 * if any of the eventmask bits we want to set are already captured. 97 * We cannot usefully capture the same fd event more than once in the 98 * same context. 99 */ 100 if (id != NULL && FindFD(ctx, fd, eventmask) != NULL) 101 EV_ERR(ETOOMANYREFS); 102 103 /* Allocate and fill. */ 104 OKNEW(id); 105 id->func = func; 106 id->uap = uap; 107 id->fd = fd; 108 id->eventmask = eventmask; 109 110 /* 111 * Insert at head. Order could be important for performance if we 112 * believe that evGetNext()'s accesses to the fd_sets will be more 113 * serial and therefore more cache-lucky if the list is ordered by 114 * ``fd.'' We do not believe these things, so we don't do it. 115 * 116 * The interesting sequence is where GetNext() has cached a select() 117 * result and the caller decides to evSelectFD() on some descriptor. 118 * Since GetNext() starts at the head, it can miss new entries we add 119 * at the head. This is not a serious problem since the event being 120 * evSelectFD()'d for has to occur before evSelectFD() is called for 121 * the file event to be considered "missed" -- a real corner case. 122 * Maintaining a "tail" pointer for ctx->files would fix this, but I'm 123 * not sure it would be ``more correct.'' 124 */ 125 if (ctx->files != NULL) 126 ctx->files->prev = id; 127 id->prev = NULL; 128 id->next = ctx->files; 129 ctx->files = id; 130 131 /* Insert into fd table. */ 132 if (ctx->fdTable[fd] != NULL) 133 ctx->fdTable[fd]->fdprev = id; 134 id->fdprev = NULL; 135 id->fdnext = ctx->fdTable[fd]; 136 ctx->fdTable[fd] = id; 137 138 /* Turn on the appropriate bits in the {rd,wr,ex}Next fd_set's. */ 139 if (eventmask & EV_READ) 140 FD_SET(fd, &ctx->rdNext); 141 if (eventmask & EV_WRITE) 142 FD_SET(fd, &ctx->wrNext); 143 if (eventmask & EV_EXCEPT) 144 FD_SET(fd, &ctx->exNext); 145 146 /* Update fdMax. */ 147 if (fd > ctx->fdMax) 148 ctx->fdMax = fd; 149 150 /* Remember the ID if the caller provided us a place for it. */ 151 if (opaqueID) 152 opaqueID->opaque = id; 153 154 return (0); 155} 156 157int 158evDeselectFD(evContext opaqueCtx, evFileID opaqueID) { 159 evContext_p *ctx = opaqueCtx.opaque; 160 evFile *del = opaqueID.opaque; 161 evFile *cur; 162 int mode, eventmask; 163 164 if (!del) { 165 evPrintf(ctx, 11, "evDeselectFD(NULL) ignored\n"); 166 errno = EINVAL; 167 return (-1); 168 } 169 170 evPrintf(ctx, 1, "evDeselectFD(fd %d, mask 0x%x)\n", 171 del->fd, del->eventmask); 172 173 /* Get the mode. Unless the file has been closed, errors are bad. */ 174 mode = fcntl(del->fd, F_GETFL, NULL); 175 if (mode == -1 && errno != EBADF) 176 EV_ERR(errno); 177 178 /* Remove from the list of files. */ 179 if (del->prev != NULL) 180 del->prev->next = del->next; 181 else 182 ctx->files = del->next; 183 if (del->next != NULL) 184 del->next->prev = del->prev; 185 186 /* Remove from the fd table. */ 187 if (del->fdprev != NULL) 188 del->fdprev->fdnext = del->fdnext; 189 else 190 ctx->fdTable[del->fd] = del->fdnext; 191 if (del->fdnext != NULL) 192 del->fdnext->fdprev = del->fdprev; 193 194 /* 195 * If the file descriptor does not appear in any other select() entry, 196 * and if !EV_WASNONBLOCK, and if we got no EBADF when we got the mode 197 * earlier, then: restore the fd to blocking status. 198 */ 199 if (!(cur = FindFD(ctx, del->fd, EV_MASK_ALL)) && 200 !FD_ISSET(del->fd, &ctx->nonblockBefore) && 201 mode != -1) { 202 /* 203 * Note that we won't return an error status to the caller if 204 * this fcntl() fails since (a) we've already done the work 205 * and (b) the caller didn't ask us anything about O_NONBLOCK. 206 */ 207#ifdef USE_FIONBIO_IOCTL 208 int off = 0; 209 (void) ioctl(del->fd, FIONBIO, (char *)&off); 210#else 211 (void) fcntl(del->fd, F_SETFL, mode & ~PORT_NONBLOCK); 212#endif 213 } 214 215 /* 216 * Now find all other uses of this descriptor and OR together an event 217 * mask so that we don't turn off {rd,wr,ex}Next bits that some other 218 * file event is using. As an optimization, stop if the event mask 219 * fills. 220 */ 221 eventmask = 0; 222 for ((void)NULL; 223 cur != NULL && eventmask != EV_MASK_ALL; 224 cur = cur->next) 225 if (cur->fd == del->fd) 226 eventmask |= cur->eventmask; 227 228 /* OK, now we know which bits we can clear out. */ 229 if (!(eventmask & EV_READ)) { 230 FD_CLR(del->fd, &ctx->rdNext); 231 if (FD_ISSET(del->fd, &ctx->rdLast)) { 232 FD_CLR(del->fd, &ctx->rdLast); 233 ctx->fdCount--; 234 } 235 } 236 if (!(eventmask & EV_WRITE)) { 237 FD_CLR(del->fd, &ctx->wrNext); 238 if (FD_ISSET(del->fd, &ctx->wrLast)) { 239 FD_CLR(del->fd, &ctx->wrLast); 240 ctx->fdCount--; 241 } 242 } 243 if (!(eventmask & EV_EXCEPT)) { 244 FD_CLR(del->fd, &ctx->exNext); 245 if (FD_ISSET(del->fd, &ctx->exLast)) { 246 FD_CLR(del->fd, &ctx->exLast); 247 ctx->fdCount--; 248 } 249 } 250 251 /* If this was the maxFD, find the new one. */ 252 if (del->fd == ctx->fdMax) { 253 ctx->fdMax = -1; 254 for (cur = ctx->files; cur; cur = cur->next) 255 if (cur->fd > ctx->fdMax) 256 ctx->fdMax = cur->fd; 257 } 258 259 /* If this was the fdNext, cycle that to the next entry. */ 260 if (del == ctx->fdNext) 261 ctx->fdNext = del->next; 262 263 /* Couldn't free it before now since we were using fields out of it. */ 264 FREE(del); 265 266 return (0); 267} 268 269static evFile * 270FindFD(const evContext_p *ctx, int fd, int eventmask) { 271 evFile *id; 272 273 for (id = ctx->fdTable[fd]; id != NULL; id = id->fdnext) 274 if (id->fd == fd && (id->eventmask & eventmask) != 0) 275 break; 276 return (id); 277} 278 279/*! \file */ 280