/* -*-c-*-
*
- * $Id: sel.c,v 1.4 1999/08/19 18:30:26 mdw Exp $
+ * $Id: sel.c,v 1.8 2000/03/23 20:42:08 mdw Exp $
*
* I/O multiplexing support
*
/*----- Revision history --------------------------------------------------*
*
* $Log: sel.c,v $
+ * Revision 1.8 2000/03/23 20:42:08 mdw
+ * Rearrange timeout handling to avoid list corruptions.
+ *
+ * Revision 1.7 1999/12/11 11:12:17 mdw
+ * Fix comment formatting error.
+ *
+ * Revision 1.6 1999/09/26 14:28:11 mdw
+ * (sel_select): Almost pointless efficiency tweak.
+ *
+ * Revision 1.5 1999/08/31 17:42:22 mdw
+ * New function `sel_force' to force a descriptor to be `selected'.
+ *
* Revision 1.4 1999/08/19 18:30:26 mdw
* Implement hooks for foreign select-using systems (currently not well
* tested).
void sel_init(sel_state *s)
{
- s->files = 0;
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ s->files[i] = 0;
+ FD_ZERO(&s->fd[i]);
+ }
s->timers = 0;
s->hooks = 0;
- FD_ZERO(&s->fd[SEL_READ]);
- FD_ZERO(&s->fd[SEL_WRITE]);
- FD_ZERO(&s->fd[SEL_EXC]);
+ s->args = 0;
}
/* --- @sel_initfile@ --- *
void sel_addfile(sel_file *f)
{
- sel_file **ff = &f->s->files;
+ sel_file **ff = &f->s->files[f->mode];
/* --- This little dance looks like line-noise, but it does the job --- */
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
}
/* --- @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
/* --- Initialize the argument block --- */
- a.maxfd = s->files ? s->files->fd + 1 : 0;
+ {
+ 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);
TV_SUB(&a.tv, &s->timers->tv, &a.now);
a.tvp = &a.tv;
}
+ s->args = &a;
/* --- Grind through the pre hooks --- */
if ((err = select(a.maxfd,
&a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC],
- a.tvp)) < 0)
+ a.tvp)) < 0) {
+ s->args = 0;
return (err);
+ }
if (a.tvp)
gettimeofday(&a.now, 0);
/* --- Run through the timers --- */
- {
+ if (s->timers && TV_CMP(&s->timers->tv, <=, &a.now)) {
sel_timer *t, *tt;
- for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = tt) {
+ tt = s->timers;
+ for (t = tt; t && TV_CMP(&t->tv, <=, &a.now); t = t->next)
+ ;
+ if (t) {
+ t->prev->next = 0;
+ t->prev = (sel_timer *)&s->timers;
+ }
+ s->timers = t;
+ for (t = tt; t; t = tt) {
tt = t->next;
- t->next = t->prev = t;
t->func(&a.now, t->p);
}
- s->timers = t;
- if (t)
- t->prev = (sel_timer *)&s->timers;
}
- /* --- And finally run through the files --- */
+ /* --- 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.
+ */
{
- sel_file *f, *ff;
- for (f = s->files; f; f = ff) {
- ff = f->next;
- if (FD_ISSET(f->fd, a.fd + f->mode))
- f->func(f->fd, f->mode, f->p);
+ int i;
+
+ for (i = 0; i < SEL_MODES; i++) {
+ sel_file *f, *ff;
+ for (f = s->files[i]; f; f = ff) {
+ ff = f->next;
+ if (FD_ISSET(f->fd, a.fd + i))
+ f->func(f->fd, i, f->p);
+ }
}
}
+ s->args = 0;
return (0);
}