--- /dev/null
+/* -*-c-*-
+ *
+ * I/O multiplexing support
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib 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 Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "sel.h"
+#include "sub.h"
+#include "tv.h"
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct sel_pendfile {
+ struct sel_pendfile *next;
+ sel_file *f;
+} pfile;
+
+typedef struct sel_pendtimer {
+ struct sel_pendtimer *next;
+ sel_timer *t;
+} ptimer;
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @sel_init@ --- *
+ *
+ * Arguments: @sel_state *s@ = pointer to a state block to initialize
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a select state block.
+ */
+
+void sel_init(sel_state *s)
+{
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ s->files[i] = 0;
+ FD_ZERO(&s->fd[i]);
+ }
+ s->timers = 0;
+ s->hooks = 0;
+ s->args = 0;
+}
+
+/* --- @sel_initfile@ --- *
+ *
+ * Arguments: @sel_state *s@ = select state to attach to
+ * @sel_file *f@ = pointer to a file block to initialize
+ * @int fd@ = the file descriptor to listen to
+ * @unsigned mode@ = what to listen for
+ * @void (*func)(int fd, unsigned mode, void *p)@ = handler
+ * @void *p@ = argument to pass to handler
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a file block ready for use. The file block
+ * isn't added to the list of things to do until a call to
+ * @sel_addfile@.
+ */
+
+void sel_initfile(sel_state *s, sel_file *f,
+ int fd, unsigned mode,
+ void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/),
+ void *p)
+{
+ f->s = s;
+ f->fd = fd;
+ f->mode = mode;
+ f->func = func;
+ f->p = p;
+ f->pend = 0;
+}
+
+/* --- @sel_addfile@ --- *
+ *
+ * Arguments: @sel_file *f@ = pointer to a file block
+ *
+ * Returns: ---
+ *
+ * Use: Adds a file block into the list of things to listen to.
+ */
+
+void sel_addfile(sel_file *f)
+{
+ sel_file **ff = &f->s->files[f->mode];
+
+ /* --- This little dance looks like line-noise, but it does the job --- */
+
+ while (*ff && (*ff)->fd > f->fd)
+ ff = &(*ff)->next;
+ f->next = *ff;
+ f->prev = ff;
+ if (*ff)
+ (*ff)->prev = &f->next;
+ *ff = f;
+ FD_SET(f->fd, f->s->fd + f->mode);
+}
+
+/* --- @sel_force@ --- *
+ *
+ * Arguments: @sel_file *f@ = pointer to file selector
+ *
+ * Returns: ---
+ *
+ * Use: Forces a file selector to be considered ready. This is only
+ * useful during a call to @sel_select@. Of particular use is
+ * forcing a write selector when there's something interesting
+ * ready for it.
+ */
+
+void sel_force(sel_file *f)
+{
+ if (f->s->args)
+ FD_SET(f->fd, &f->s->args->fd[f->mode]);
+}
+
+/* --- @sel_rmfile@ --- *
+ *
+ * Arguments: @sel_file *f@ = pointer to a file block
+ *
+ * Returns: ---
+ *
+ * Use: Removes a file block from the list of things to listen to.
+ */
+
+void sel_rmfile(sel_file *f)
+{
+ *f->prev = f->next;
+ if (f->next)
+ f->next->prev = f->prev;
+ FD_CLR(f->fd, f->s->fd + f->mode);
+ if (f->pend) {
+ f->pend->f = 0;
+ f->pend = 0;
+ }
+}
+
+/* --- @sel_addtimer@ --- *
+ *
+ * Arguments: @sel_state *s@ = pointer to a state block
+ * @sel_timer *t@ = pointer to a timer block
+ * @struct timeval *tv@ = pointer to time to activate
+ * @void (*func)(struct timeval *tv, void *p)@ = handler
+ * @void *p@ = argument for handler function
+ *
+ * Returns: ---
+ *
+ * Use: Registers and sets up a timer.
+ */
+
+void sel_addtimer(sel_state *s, sel_timer *t,
+ struct timeval *tv,
+ void (*func)(struct timeval */*tv*/, void */*p*/),
+ void *p)
+{
+ sel_timer **tt = &s->timers;
+ { sel_timer *q; for (q = s->timers; q; q = q->next) assert(q != t); }
+
+ /* --- Set up the timer block --- */
+
+ t->tv = *tv;
+ t->func = func;
+ t->p = p;
+ t->pend = 0;
+
+ /* --- More line noise --- */
+
+ while (*tt && TV_CMP(&(*tt)->tv, <, tv))
+ tt = &(*tt)->next;
+ t->next = *tt;
+ t->prev = tt;
+ if (*tt)
+ (*tt)->prev = &t->next;
+ *tt = t;
+}
+
+/* --- @sel_rmtimer@ --- *
+ *
+ * Arguments: @sel_timer *t@ = pointer to timer block
+ *
+ * Returns: ---
+ *
+ * Use: Removes a timer from the list of timers.
+ */
+
+void sel_rmtimer(sel_timer *t)
+{
+ if (t->pend) {
+ t->pend->t = 0;
+ t->pend = 0;
+ } else {
+ *t->prev = t->next;
+ if (t->next)
+ t->next->prev = t->prev;
+ }
+}
+
+/* --- @sel_addhook@ --- *
+ *
+ * Arguments: @sel_state *s@ = pointer to state block
+ * @sel_hook *h@ = pointer to hook block
+ * @sel_hookfn before, after@ = hook functions
+ * @void *p@ = pointer argument to pass to hook functions
+ *
+ * Returns: ---
+ *
+ * Use: Registers hook functions to be called on each select call.
+ */
+
+void sel_addhook(sel_state *s, sel_hook *h,
+ sel_hookfn before, sel_hookfn after,
+ void *p)
+{
+ h->before = before;
+ h->after = after;
+ h->p = p;
+ h->next = s->hooks;
+ h->prev = &s->hooks;
+ if (s->hooks)
+ s->hooks->prev = &h->next;
+ s->hooks = h;
+}
+
+/* --- @sel_rmhook@ --- *
+ *
+ * Arguments: @sel_hook *h@ = pointer to hook block
+ *
+ * Returns: ---
+ *
+ * Use: Removes hook functions.
+ */
+
+void sel_rmhook(sel_hook *h)
+{
+ if (h->next)
+ h->next->prev = h->prev;
+ *h->prev = h->next;
+}
+
+/* --- @sel_fdmerge@ --- *
+ *
+ * Arguments: @fd_set *dest@ = destination FD set
+ * @fd_set *fd@ = pointer to set to merge
+ * @int maxfd@ = highest numbered descriptor in @fd@ + 1
+ *
+ * Returns: Actual highest numbered descriptor.
+ *
+ * Use: Merges file descriptor sets, and returns an accurate @maxfd@
+ * value.
+ */
+
+int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd)
+{
+ int i, m = -1;
+
+ for (i = 0; i < maxfd; i++) {
+ if (FD_ISSET(i, fd)) {
+ FD_SET(i, dest);
+ m = i;
+ }
+ }
+
+ return (m + 1);
+}
+
+/* --- @sel_select@ --- *
+ *
+ * Arguments: @sel_state *s@ = pointer to state block
+ *
+ * Returns: Zero if all OK, -1 on error.
+ *
+ * Use: Does a @select@ call (or equivalent @poll@).
+ */
+
+int sel_select(sel_state *s)
+{
+ sel_args a;
+ int err;
+
+ /* --- Initialize the argument block --- */
+
+ {
+ int i;
+ a.maxfd = 0;
+ for (i = 0; i < SEL_MODES; i++) {
+ if (s->files[i] && s->files[i]->fd >= a.maxfd)
+ a.maxfd = s->files[i]->fd + 1;
+ }
+ }
+
+ memcpy(a.fd, s->fd, sizeof(a.fd));
+ if (s->timers || s->hooks)
+ gettimeofday(&a.now, 0);
+ if (!s->timers)
+ a.tvp = 0;
+ else {
+ if (TV_CMP(&s->timers->tv, >, &a.now))
+ TV_SUB(&a.tv, &s->timers->tv, &a.now);
+ else {
+ a.tv.tv_sec = 0;
+ a.tv.tv_usec = 0;
+ }
+ a.tvp = &a.tv;
+ }
+ s->args = &a;
+
+ /* --- Grind through the pre hooks --- */
+
+ {
+ sel_hook *h = s->hooks;
+ while (h) {
+ sel_hook *hh = h;
+ h = h->next;
+ if (hh->before)
+ hh->before(s, &a, hh->p);
+ }
+ }
+
+ /* --- Run the @select@ call --- */
+
+ if ((err = select(a.maxfd,
+ &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC],
+ a.tvp)) < 0) {
+ s->args = 0;
+ return (err);
+ }
+
+ if (a.tvp)
+ gettimeofday(&a.now, 0);
+
+ /* --- Run through the hooks again --- */
+
+ {
+ sel_hook *h = s->hooks;
+ while (h) {
+ sel_hook *hh = h;
+ h = h->next;
+ if (hh->after)
+ hh->after(s, &a, hh->p);
+ }
+ }
+
+ /* --- Run through the timers --- */
+
+ if (s->timers) {
+ ptimer *pthead, *pt, **ptt = &pthead;
+ sel_timer *t;
+
+ for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = t->next) {
+ pt = CREATE(ptimer);
+ pt->t = t;
+ t->pend = pt;
+ *ptt = pt;
+ ptt = &pt->next;
+ }
+ *ptt = 0;
+ if (t) {
+ *t->prev = 0;
+ t->prev = &s->timers;
+ }
+ s->timers = t;
+ while (pthead) {
+ pt = pthead;
+ pthead = pt->next;
+ t = pt->t;
+ if (t) {
+ t->pend = 0;
+ t->next = 0;
+ t->prev = &t->next;
+ t->func(&a.now, t->p);
+ }
+ DESTROY(pt);
+ }
+ }
+
+ /* --- And finally run through the files --- *
+ *
+ * Do reads first. It's quite possible that a read might prompt a write,
+ * but the other way around is less likely. Fortunately, the modes are
+ * in the right order for this.
+ */
+
+ {
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ pfile *pfhead, *pf, **pff = &pfhead;
+ sel_file *f;
+
+ for (f = s->files[i]; f; f = f->next) {
+ if (!FD_ISSET(f->fd, &a.fd[i]))
+ continue;
+ pf = CREATE(pfile);
+ pf->f = f;
+ f->pend = pf;
+ *pff = pf;
+ pff = &pf->next;
+ }
+ *pff = 0;
+ while (pfhead) {
+ pf = pfhead;
+ pfhead = pf->next;
+ f = pf->f;
+ if (f) {
+ f->pend = 0;
+ f->func(f->fd, i, f->p);
+ }
+ DESTROY(pf);
+ }
+ }
+ }
+
+ s->args = 0;
+ return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / mLib / blobdiff