/* * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") * Copyright (c) 1995-1999 by Internet Software Consortium * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* ev_files.c - implement asynch file IO for the eventlib * vix 11sep95 [initial] */ #if !defined(LINT) && !defined(CODECENTER) static const char rcsid[] = "$Id: ev_files.c,v 1.8 2005/07/28 06:51:48 marka Exp $"; #endif #include "port_before.h" #include "fd_setsize.h" #include <sys/types.h> #include <sys/time.h> #include <sys/ioctl.h> #include <errno.h> #include <fcntl.h> #include <unistd.h> #include <isc/eventlib.h> #include "eventlib_p.h" #include "port_after.h" static evFile *FindFD(const evContext_p *ctx, int fd, int eventmask); int evSelectFD(evContext opaqueCtx, int fd, int eventmask, evFileFunc func, void *uap, evFileID *opaqueID ) { evContext_p *ctx = opaqueCtx.opaque; evFile *id; int mode; evPrintf(ctx, 1, "evSelectFD(ctx %p, fd %d, mask 0x%x, func %p, uap %p)\n", ctx, fd, eventmask, func, uap); if (eventmask == 0 || (eventmask & ~EV_MASK_ALL) != 0) EV_ERR(EINVAL); #ifndef USE_POLL if (fd > ctx->highestFD) EV_ERR(EINVAL); #endif OK(mode = fcntl(fd, F_GETFL, NULL)); /*%< side effect: validate fd. */ /* * The first time we touch a file descriptor, we need to check to see * if the application already had it in O_NONBLOCK mode and if so, all * of our deselect()'s have to leave it in O_NONBLOCK. If not, then * all but our last deselect() has to leave it in O_NONBLOCK. */ #ifdef USE_POLL /* Make sure both ctx->pollfds[] and ctx->fdTable[] are large enough */ if (fd >= ctx->maxnfds && evPollfdRealloc(ctx, 1, fd) != 0) EV_ERR(ENOMEM); #endif /* USE_POLL */ id = FindFD(ctx, fd, EV_MASK_ALL); if (id == NULL) { if (mode & PORT_NONBLOCK) FD_SET(fd, &ctx->nonblockBefore); else { #ifdef USE_FIONBIO_IOCTL int on = 1; OK(ioctl(fd, FIONBIO, (char *)&on)); #else OK(fcntl(fd, F_SETFL, mode | PORT_NONBLOCK)); #endif FD_CLR(fd, &ctx->nonblockBefore); } } /* * If this descriptor is already in use, search for it again to see * if any of the eventmask bits we want to set are already captured. * We cannot usefully capture the same fd event more than once in the * same context. */ if (id != NULL && FindFD(ctx, fd, eventmask) != NULL) EV_ERR(ETOOMANYREFS); /* Allocate and fill. */ OKNEW(id); id->func = func; id->uap = uap; id->fd = fd; id->eventmask = eventmask; /* * Insert at head. Order could be important for performance if we * believe that evGetNext()'s accesses to the fd_sets will be more * serial and therefore more cache-lucky if the list is ordered by * ``fd.'' We do not believe these things, so we don't do it. * * The interesting sequence is where GetNext() has cached a select() * result and the caller decides to evSelectFD() on some descriptor. * Since GetNext() starts at the head, it can miss new entries we add * at the head. This is not a serious problem since the event being * evSelectFD()'d for has to occur before evSelectFD() is called for * the file event to be considered "missed" -- a real corner case. * Maintaining a "tail" pointer for ctx->files would fix this, but I'm * not sure it would be ``more correct.'' */ if (ctx->files != NULL) ctx->files->prev = id; id->prev = NULL; id->next = ctx->files; ctx->files = id; /* Insert into fd table. */ if (ctx->fdTable[fd] != NULL) ctx->fdTable[fd]->fdprev = id; id->fdprev = NULL; id->fdnext = ctx->fdTable[fd]; ctx->fdTable[fd] = id; /* Turn on the appropriate bits in the {rd,wr,ex}Next fd_set's. */ if (eventmask & EV_READ) FD_SET(fd, &ctx->rdNext); if (eventmask & EV_WRITE) FD_SET(fd, &ctx->wrNext); if (eventmask & EV_EXCEPT) FD_SET(fd, &ctx->exNext); /* Update fdMax. */ if (fd > ctx->fdMax) ctx->fdMax = fd; /* Remember the ID if the caller provided us a place for it. */ if (opaqueID) opaqueID->opaque = id; return (0); } int evDeselectFD(evContext opaqueCtx, evFileID opaqueID) { evContext_p *ctx = opaqueCtx.opaque; evFile *del = opaqueID.opaque; evFile *cur; int mode, eventmask; if (!del) { evPrintf(ctx, 11, "evDeselectFD(NULL) ignored\n"); errno = EINVAL; return (-1); } evPrintf(ctx, 1, "evDeselectFD(fd %d, mask 0x%x)\n", del->fd, del->eventmask); /* Get the mode. Unless the file has been closed, errors are bad. */ mode = fcntl(del->fd, F_GETFL, NULL); if (mode == -1 && errno != EBADF) EV_ERR(errno); /* Remove from the list of files. */ if (del->prev != NULL) del->prev->next = del->next; else ctx->files = del->next; if (del->next != NULL) del->next->prev = del->prev; /* Remove from the fd table. */ if (del->fdprev != NULL) del->fdprev->fdnext = del->fdnext; else ctx->fdTable[del->fd] = del->fdnext; if (del->fdnext != NULL) del->fdnext->fdprev = del->fdprev; /* * If the file descriptor does not appear in any other select() entry, * and if !EV_WASNONBLOCK, and if we got no EBADF when we got the mode * earlier, then: restore the fd to blocking status. */ if (!(cur = FindFD(ctx, del->fd, EV_MASK_ALL)) && !FD_ISSET(del->fd, &ctx->nonblockBefore) && mode != -1) { /* * Note that we won't return an error status to the caller if * this fcntl() fails since (a) we've already done the work * and (b) the caller didn't ask us anything about O_NONBLOCK. */ #ifdef USE_FIONBIO_IOCTL int off = 0; (void) ioctl(del->fd, FIONBIO, (char *)&off); #else (void) fcntl(del->fd, F_SETFL, mode & ~PORT_NONBLOCK); #endif } /* * Now find all other uses of this descriptor and OR together an event * mask so that we don't turn off {rd,wr,ex}Next bits that some other * file event is using. As an optimization, stop if the event mask * fills. */ eventmask = 0; for ((void)NULL; cur != NULL && eventmask != EV_MASK_ALL; cur = cur->next) if (cur->fd == del->fd) eventmask |= cur->eventmask; /* OK, now we know which bits we can clear out. */ if (!(eventmask & EV_READ)) { FD_CLR(del->fd, &ctx->rdNext); if (FD_ISSET(del->fd, &ctx->rdLast)) { FD_CLR(del->fd, &ctx->rdLast); ctx->fdCount--; } } if (!(eventmask & EV_WRITE)) { FD_CLR(del->fd, &ctx->wrNext); if (FD_ISSET(del->fd, &ctx->wrLast)) { FD_CLR(del->fd, &ctx->wrLast); ctx->fdCount--; } } if (!(eventmask & EV_EXCEPT)) { FD_CLR(del->fd, &ctx->exNext); if (FD_ISSET(del->fd, &ctx->exLast)) { FD_CLR(del->fd, &ctx->exLast); ctx->fdCount--; } } /* If this was the maxFD, find the new one. */ if (del->fd == ctx->fdMax) { ctx->fdMax = -1; for (cur = ctx->files; cur; cur = cur->next) if (cur->fd > ctx->fdMax) ctx->fdMax = cur->fd; } /* If this was the fdNext, cycle that to the next entry. */ if (del == ctx->fdNext) ctx->fdNext = del->next; /* Couldn't free it before now since we were using fields out of it. */ FREE(del); return (0); } static evFile * FindFD(const evContext_p *ctx, int fd, int eventmask) { evFile *id; for (id = ctx->fdTable[fd]; id != NULL; id = id->fdnext) if (id->fd == fd && (id->eventmask & eventmask) != 0) break; return (id); } /*! \file */