svn commit: r283440 - in head/sys: kern sys

[Dmitry Chagin]

Author: dchagin
Date: Sun May 24 16:36:29 2015
New Revision: 283440
URL: https://svnweb.freebsd.org/changeset/base/283440

Log:
  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]
  
  Differential Revision:	https://reviews.freebsd.org/D1091
  Reviewed by:	trasz

Modified:
  head/sys/kern/kern_event.c
  head/sys/sys/syscallsubr.h

Modified: head/sys/kern/kern_event.c
==============================================================================
--- head/sys/kern/kern_event.c	Sun May 24 16:34:57 2015	(r283439)
+++ head/sys/kern/kern_event.c	Sun May 24 16:36:29 2015	(r283440)
@@ -737,6 +737,13 @@ filt_usertouch(struct knote *kn, struct 
 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;
@@ -757,7 +764,7 @@ sys_kqueue(struct thread *td, struct kqu
 	PROC_UNLOCK(p);
 
 	fdp = p->p_fd;
-	error = falloc(td, &fp, &fd, 0);
+	error = falloc(td, &fp, &fd, flags);
 	if (error)
 		goto done2;
 
@@ -888,12 +895,9 @@ 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)
@@ -904,9 +908,24 @@ kern_kevent(struct thread *td, int fd, i
 	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;
 
@@ -946,8 +965,6 @@ kern_kevent(struct thread *td, int fd, i
 	error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
 done:
 	kqueue_release(kq, 0);
-done_norel:
-	fdrop(fp, td);
 	return (error);
 }
 

Modified: head/sys/sys/syscallsubr.h
==============================================================================
--- head/sys/sys/syscallsubr.h	Sun May 24 16:34:57 2015	(r283439)
+++ head/sys/sys/syscallsubr.h	Sun May 24 16:36:29 2015	(r283440)
@@ -121,6 +121,10 @@ int	kern_jail_get(struct thread *td, str
 int	kern_jail_set(struct thread *td, struct uio *options, int flags);
 int	kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
 	    struct kevent_copyops *k_ops, const struct timespec *timeout);
+int	kern_kevent_fp(struct thread *td, struct file *fp, int nchanges,
+	    int nevents, struct kevent_copyops *k_ops,
+	    const struct timespec *timeout);
+int	kern_kqueue(struct thread *td, int flags);
 int	kern_kldload(struct thread *td, const char *file, int *fileid);
 int	kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat);
 int	kern_kldunload(struct thread *td, int fileid, int flags);