MFC r283440:

For future use in the Linuxulator:

1. Add a kern_kqueue() counterpart for kqueue() with flags parameter.

2. Be a bit secure. To avoid a double fp lookup add a kern_kevent_fp()
counterpart for kern_kevent() with file pointer parameter instead
of file descriptor an pass the buck to it.

Suggested by: mjg [2]

1 files changed, 26 insertions, 9 deletions

diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index dae1d54..e665a8e 100644
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -731,13 +731,20 @@ filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
 int
 sys_kqueue(struct thread *td, struct kqueue_args *uap)
 {
+
+	return (kern_kqueue(td, 0));
+}
+
+int
+kern_kqueue(struct thread *td, int flags)
+{
 	struct filedesc *fdp;
 	struct kqueue *kq;
 	struct file *fp;
 	int fd, error;
 
 	fdp = td->td_proc->p_fd;
-	error = falloc(td, &fp, &fd, 0);
+	error = falloc(td, &fp, &fd, flags);
 	if (error)
 		goto done2;
 
@@ -863,12 +870,9 @@ int
 kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
     struct kevent_copyops *k_ops, const struct timespec *timeout)
 {
-	struct kevent keva[KQ_NEVENTS];
-	struct kevent *kevp, *changes;
-	struct kqueue *kq;
-	struct file *fp;
 	cap_rights_t rights;
-	int i, n, nerrors, error;
+	struct file *fp;
+	int error;
 
 	cap_rights_init(&rights);
 	if (nchanges > 0)
@@ -879,9 +883,24 @@ kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
 	if (error != 0)
 		return (error);
 
+	error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
+	fdrop(fp, td);
+
+	return (error);
+}
+
+int
+kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
+    struct kevent_copyops *k_ops, const struct timespec *timeout)
+{
+	struct kevent keva[KQ_NEVENTS];
+	struct kevent *kevp, *changes;
+	struct kqueue *kq;
+	int i, n, nerrors, error;
+
 	error = kqueue_acquire(fp, &kq);
 	if (error != 0)
-		goto done_norel;
+		return (error);
 
 	nerrors = 0;
 
@@ -921,8 +940,6 @@ kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
 	error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
 done:
 	kqueue_release(kq, 0);
-done_norel:
-	fdrop(fp, td);
 	return (error);
 }