[src/trunk]: src/sys/kern Implement eventfd_ioctl() and handle FIONBIO so tha...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/11b3dd5b918e
branches:  trunk
changeset: 361607:11b3dd5b918e
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Thu Feb 17 16:28:29 2022 +0000

description:
Implement eventfd_ioctl() and handle FIONBIO so that fcntl(O_NONBLOCK)
works.  While here, also implement FIONREAD and FIONWRITE, and document
why we don't implement FIONSPACE.

Also implement FIONBIO and FIONREAD for in timerfd_ioctl() (for the same
reason).

PR kern/56718

diffstat:

 sys/kern/sys_eventfd.c |  39 ++++++++++++++++++++++++++++++++++++---
 sys/kern/sys_timerfd.c |  13 +++++++++++--
 2 files changed, 47 insertions(+), 5 deletions(-)

diffs (101 lines):

diff -r 32b2cbfd0a77 -r 11b3dd5b918e sys/kern/sys_eventfd.c
--- a/sys/kern/sys_eventfd.c    Thu Feb 17 16:09:00 2022 +0000
+++ b/sys/kern/sys_eventfd.c    Thu Feb 17 16:28:29 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_eventfd.c,v 1.8 2021/11/24 16:35:33 thorpej Exp $  */
+/*     $NetBSD: sys_eventfd.c,v 1.9 2022/02/17 16:28:29 thorpej Exp $  */
 
 /*-
  * Copyright (c) 2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_eventfd.c,v 1.8 2021/11/24 16:35:33 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_eventfd.c,v 1.9 2022/02/17 16:28:29 thorpej Exp $");
 
 /*
  * eventfd
@@ -310,6 +310,39 @@
 }
 
 static int
+eventfd_ioctl(file_t * const fp, u_long const cmd, void * const data)
+{
+       struct eventfd * const efd = fp->f_eventfd;
+
+       switch (cmd) {
+       case FIONBIO:
+               return 0;
+       
+       case FIONREAD:
+               mutex_enter(&efd->efd_lock);
+               *(int *)data = efd->efd_val != 0 ? sizeof(eventfd_t) : 0;
+               mutex_exit(&efd->efd_lock);
+               return 0;
+       
+       case FIONWRITE:
+               *(int *)data = 0;
+               return 0;
+
+       case FIONSPACE:
+               /*
+                * FIONSPACE doesn't really work for eventfd, because the
+                * writability depends on the contents (value) being written.
+                */
+               break;
+
+       default:
+               break;
+       }
+
+       return EPASSTHROUGH;
+}
+
+static int
 eventfd_fop_poll(file_t * const fp, int const events)
 {
        struct eventfd * const efd = fp->f_eventfd;
@@ -521,7 +554,7 @@
        .fo_name = "eventfd",
        .fo_read = eventfd_fop_read,
        .fo_write = eventfd_fop_write,
-       .fo_ioctl = fbadop_ioctl,
+       .fo_ioctl = eventfd_ioctl,
        .fo_fcntl = fnullop_fcntl,
        .fo_poll = eventfd_fop_poll,
        .fo_stat = eventfd_fop_stat,
diff -r 32b2cbfd0a77 -r 11b3dd5b918e sys/kern/sys_timerfd.c
--- a/sys/kern/sys_timerfd.c    Thu Feb 17 16:09:00 2022 +0000
+++ b/sys/kern/sys_timerfd.c    Thu Feb 17 16:28:29 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_timerfd.c,v 1.7 2021/11/24 16:35:33 thorpej Exp $  */
+/*     $NetBSD: sys_timerfd.c,v 1.8 2022/02/17 16:28:29 thorpej Exp $  */
 
 /*-
  * Copyright (c) 2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_timerfd.c,v 1.7 2021/11/24 16:35:33 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_timerfd.c,v 1.8 2022/02/17 16:28:29 thorpej Exp $");
 
 /*
  * timerfd
@@ -306,6 +306,15 @@
        int error = 0;
 
        switch (cmd) {
+       case FIONBIO:
+               break;
+
+       case FIONREAD:
+               itimer_lock();
+               *(int *)data = timerfd_is_readable(tfd) ? sizeof(uint64_t) : 0;
+               itimer_unlock();
+               break;
+
        case TFD_IOC_SET_TICKS: {
                const uint64_t * const new_ticksp = data;
                if (*new_ticksp > INT_MAX) {