/* -*-c-*-
*
- * $Id: sel.c,v 1.4 1999/08/19 18:30:26 mdw Exp $
+ * $Id: sel.c,v 1.10 2001/06/22 19:35:58 mdw Exp $
*
* I/O multiplexing support
*
/*----- Revision history --------------------------------------------------*
*
* $Log: sel.c,v $
+ * Revision 1.10 2001/06/22 19:35:58 mdw
+ * Fix a large number of bugs.
+ *
+ * Revision 1.9 2001/02/03 19:07:08 mdw
+ * Ensure that timers set to go off in the past don't case a problem.
+ *
+ * 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).
/*----- Header files ------------------------------------------------------*/
+#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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@ --- *
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@ --- *
f->mode = mode;
f->func = func;
f->p = p;
+ f->pend = 0;
}
/* --- @sel_addfile@ --- *
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
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@ --- *
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 --- */
t->prev->next = t->next;
if (t->next)
t->next->prev = t->prev;
+ if (t->pend) {
+ t->pend->t = 0;
+ t->pend = 0;
+ }
}
/* --- @sel_addhook@ --- *
}
/* --- @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);
if (!s->timers)
a.tvp = 0;
else {
- TV_SUB(&a.tv, &s->timers->tv, &a.now);
+ 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 --- */
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 --- */
- {
- sel_timer *t, *tt;
- for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = tt) {
- tt = t->next;
- t->next = t->prev = t;
- t->func(&a.now, t->p);
+ 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;
}
- s->timers = t;
- if (t)
+ *ptt = 0;
+ if (t) {
+ t->prev->next = 0;
t->prev = (sel_timer *)&s->timers;
+ }
+ s->timers = t;
+ while (pthead) {
+ pt = pthead;
+ pthead = pt->next;
+ t = pt->t;
+ if (t) {
+ t->func(&a.now, t->p);
+ t->pend = 0;
+ }
+ DESTROY(pt);
+ }
}
- /* --- 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++) {
+ 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->func(f->fd, i, f->p);
+ f->pend = 0;
+ }
+ }
}
}
+ s->args = 0;
return (0);
}
~mdw / mLib / blobdiff