sndiod: Properly update the poll(2) event masks after i/o.

If there are no descriptors to poll for an event source, we call
the i/o handlers immediately (before poll(2) is called). As this
may generate output for other descriptors, their the poll(2) event
masks need to be updated.

diff --git a/usr.bin/sndiod/file.c b/usr.bin/sndiod/file.c
index 3fb8664..64a2357 100644 (file)
--- a/usr.bin/sndiod/file.c
+++ b/usr.bin/sndiod/file.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: file.c,v 1.26 2022/12/26 19:16:03 jmc Exp $   */
+/*     $OpenBSD: file.c,v 1.27 2024/07/23 06:34:03 ratchov Exp $       */
 /*
  * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -63,7 +63,7 @@
 void timo_update(unsigned int);
 void timo_init(void);
 void timo_done(void);
-void file_process(struct file *, struct pollfd *);
+int file_process(struct file *, struct pollfd *);
 
 struct timespec file_ts;
 struct file *file_list;
@@ -270,10 +270,10 @@ file_del(struct file *f)
 #endif
 }
 
-void
+int
 file_process(struct file *f, struct pollfd *pfd)
 {
-       int revents;
+       int rc, revents;
 #ifdef DEBUG
        struct timespec ts0, ts1;
        long us;
@@ -283,14 +283,21 @@ file_process(struct file *f, struct pollfd *pfd)
        if (log_level >= 3)
                clock_gettime(CLOCK_UPTIME, &ts0);
 #endif
+       rc = 0;
        revents = (f->state != FILE_ZOMB) ?
            f->ops->revents(f->arg, pfd) : 0;
-       if ((revents & POLLHUP) && (f->state != FILE_ZOMB))
+       if ((revents & POLLHUP) && (f->state != FILE_ZOMB)) {
                f->ops->hup(f->arg);
-       if ((revents & POLLIN) && (f->state != FILE_ZOMB))
+               rc = 1;
+       }
+       if ((revents & POLLIN) && (f->state != FILE_ZOMB)) {
                f->ops->in(f->arg);
-       if ((revents & POLLOUT) && (f->state != FILE_ZOMB))
+               rc = 1;
+       }
+       if ((revents & POLLOUT) && (f->state != FILE_ZOMB)) {
                f->ops->out(f->arg);
+               rc = 1;
+       }
 #ifdef DEBUG
        if (log_level >= 3) {
                clock_gettime(CLOCK_UPTIME, &ts1);
@@ -304,6 +311,7 @@ file_process(struct file *f, struct pollfd *pfd)
                }
        }
 #endif
+       return rc;
 }
 
 int
@@ -370,11 +378,19 @@ file_poll(void)
        /*
         * process files that do not rely on poll
         */
+       res = 0;
        for (f = file_list; f != NULL; f = f->next) {
                if (f->nfds > 0)
                        continue;
-               file_process(f, NULL);
+               res |= file_process(f, NULL);
        }
+       /*
+        * The processing may have changed the poll(2) conditions of
+        * other files, so restart the loop to force their poll(2) event
+        * masks to be reevaluated.
+        */
+       if (res)
+               return 1;
 
        /*
         * Sleep. Calculate the number of milliseconds poll(2) must