/* -*-c-*-
*
- * $Id: sel.c,v 1.3 1999/05/21 22:13:59 mdw Exp $
+ * $Id: sel.c,v 1.4 1999/08/19 18:30:26 mdw Exp $
*
* I/O multiplexing support
*
/*----- Revision history --------------------------------------------------*
*
* $Log: sel.c,v $
+ * Revision 1.4 1999/08/19 18:30:26 mdw
+ * Implement hooks for foreign select-using systems (currently not well
+ * tested).
+ *
* Revision 1.3 1999/05/21 22:13:59 mdw
* Use new `tv' macros. Fix ordering bug for timeout selectors.
*
{
s->files = 0;
s->timers = 0;
+ s->hooks = 0;
FD_ZERO(&s->fd[SEL_READ]);
FD_ZERO(&s->fd[SEL_WRITE]);
FD_ZERO(&s->fd[SEL_EXC]);
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 = (sel_hook *)&s->hooks;
+ if (s->hooks)
+ s->hooks->prev = h;
+ 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->next = 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
int sel_select(sel_state *s)
{
- fd_set fd[SEL_MODES];
- struct timeval tv;
+ sel_args a;
int err;
- memcpy(fd, s->fd, sizeof(s->fd));
- if (s->timers) {
- struct timeval now;
- gettimeofday(&now, 0);
- TV_SUB(&tv, &s->timers->tv, &now);
- err = select(s->files ? s->files->fd + 1 : 0,
- fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
- &tv);
- gettimeofday(&tv, 0);
- } else
- err = select(s->files ? s->files->fd + 1 : 0,
- fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
- 0);
-
- if (err < 0)
+ /* --- Initialize the argument block --- */
+
+ a.maxfd = s->files ? s->files->fd + 1 : 0;
+ 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);
+ a.tvp = &a.tv;
+ }
+
+ /* --- 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)
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 --- */
+
{
sel_timer *t, *tt;
- for (t = s->timers; t && TV_CMP(&t->tv, <=, &tv); 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(&tv, t->p);
+ t->func(&a.now, t->p);
}
s->timers = t;
if (t)
t->prev = (sel_timer *)&s->timers;
}
+ /* --- And finally run through the files --- */
+
{
sel_file *f, *ff;
for (f = s->files; f; f = ff) {
ff = f->next;
- if (FD_ISSET(f->fd, fd + f->mode))
+ if (FD_ISSET(f->fd, a.fd + f->mode))
f->func(f->fd, f->mode, f->p);
}
}
/* -*-c-*-
*
- * $Id: sel.h,v 1.4 1999/05/22 13:39:15 mdw Exp $
+ * $Id: sel.h,v 1.5 1999/08/19 18:30:26 mdw Exp $
*
* I/O multiplexing support
*
/*----- Revision history --------------------------------------------------*
*
* $Log: sel.h,v $
+ * Revision 1.5 1999/08/19 18:30:26 mdw
+ * Implement hooks for foreign select-using systems (currently not well
+ * tested).
+ *
* Revision 1.4 1999/05/22 13:39:15 mdw
* Change spelling of `multiplexor'. ;-)
*
/*----- Data structures ---------------------------------------------------*/
+/* --- A multiplexor --- *
+ *
+ * The files are sorted in reverse order of file descriptor number; the
+ * timers are in normal order of occurrence. Thus, the interesting one
+ * is always at the front of the list.
+ */
+
+enum {
+ SEL_READ,
+ SEL_WRITE,
+ SEL_EXC,
+ SEL_MODES
+};
+
+typedef struct sel_state {
+ struct sel_file *files;
+ struct sel_timer *timers;
+ struct sel_hook *hooks;
+ fd_set fd[SEL_MODES];
+ struct timeval tv;
+} sel_state;
+
/* --- Listening for a file --- */
typedef struct sel_file {
void *p;
} sel_file;
-enum {
- SEL_READ,
- SEL_WRITE,
- SEL_EXC,
- SEL_MODES
-};
-
/* --- Waiting for a timeout --- */
typedef struct sel_timer {
struct sel_timer *next;
struct sel_timer *prev;
struct timeval tv;
- void (*func)(struct timeval *tv, void *p);
+ void (*func)(struct timeval */*tv*/, void */*p*/);
void *p;
} sel_timer;
-/* --- A multiplexor --- *
+/* --- A select argument block --- */
+
+typedef struct sel_args {
+ int maxfd;
+ fd_set fd[SEL_MODES];
+ struct timeval tv, *tvp;
+ struct timeval now;
+} sel_args;
+
+/* --- A selector hook --- *
*
- * The files are sorted in reverse order of file descriptor number; the
- * timers are in normal order of occurrence. Thus, the interesting one
- * is always at the front of the list.
+ * The hooks are called (in arbitrary order) on each select.
*/
-typedef struct sel_state {
- struct sel_file *files;
- struct sel_timer *timers;
- fd_set fd[SEL_MODES];
- struct timeval tv;
-} sel_state;
+typedef void (*sel_hookfn)(sel_state */*s*/,
+ sel_args */*a*/,
+ void */*p*/);
+
+typedef struct sel_hook {
+ struct sel_hook *next;
+ struct sel_hook *prev;
+ sel_hookfn before, after;
+ void *p;
+} sel_hook;
/*----- Functions provided ------------------------------------------------*/
* 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: ---
extern void sel_rmtimer(sel_timer */*t*/);
+/* --- @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.
+ */
+
+extern void sel_addhook(sel_state */*s*/, sel_hook */*h*/,
+ sel_hookfn /*before*/, sel_hookfn /*after*/,
+ void */*p*/);
+
+/* --- @sel_rmhook@ --- *
+ *
+ * Arguments: @sel_hook *h@ = pointer to hook block
+ *
+ * Returns: ---
+ *
+ * Use: Removes hook functions.
+ */
+
+extern void sel_rmhook(sel_hook */*h*/);
+
+/* --- @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.
+ */
+
+extern int sel_fdmerge(fd_set */*dest*/, fd_set */*fd*/, int /*maxfd*/);
+
/* --- @sel_select@ --- *
*
* Arguments: @sel_state *s@ = pointer to state block