Add EVFILT_VNODE open, read and close notifications.

While there, order EVFILT_VNODE notes descriptions alphabetically.

Based on submission, and tested by:	Vladimir Kondratyev <wulf@cicgroup.ru>
MFC after:	2 weeks

5 files changed, 79 insertions, 8 deletions

diff --git a/lib/libc/sys/kqueue.2 b/lib/libc/sys/kqueue.2
index 221f451..548aeb8 100644
--- a/lib/libc/sys/kqueue.2
+++ b/lib/libc/sys/kqueue.2
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 2, 2016
+.Dd May 3, 2016
 .Dt KQUEUE 2
 .Os
 .Sh NAME
@@ -367,14 +367,28 @@ Takes a file descriptor as the identifier and the events to watch for in
 .Va fflags ,
 and returns when one or more of the requested events occurs on the descriptor.
 The events to monitor are:
-.Bl -tag -width "Dv NOTE_RENAME"
+.Bl -tag -width "Dv NOTE_CLOSE_WRITE"
+.It Dv NOTE_ATTRIB
+The file referenced by the descriptor had its attributes changed.
+.It Dv NOTE_CLOSE
+A file descriptor referencing the monitored file, was closed.
+The closed file descriptor did not possesed write access.
+.It Dv NOTE_CLOSE_WRITE
+A file descriptor referencing the monitored file, was closed.
+The closed file descriptor has write access.
+.Pp
+This note, as well as
+.Dv NOTE_CLOSE ,
+are not activated when files are closed forcibly by
+.Xr unmount 2 or
+.Xr revoke 2 .
+Instead,
+.Dv NOTE_REVOKE
+is sent for such events.
 .It Dv NOTE_DELETE
 The
 .Fn unlink
-system call
-was called on the file referenced by the descriptor.
-.It Dv NOTE_WRITE
-A write occurred on the file referenced by the descriptor.
+system call was called on the file referenced by the descriptor.
 .It Dv NOTE_EXTEND
 For regular file, the file referenced by the descriptor was extended.
 .Pp
@@ -383,20 +397,24 @@ as the result of rename operation.
 The
 .Dv NOTE_EXTEND
 event is not reported when a name is changed inside the directory.
-.It Dv NOTE_ATTRIB
-The file referenced by the descriptor had its attributes changed.
 .It Dv NOTE_LINK
 The link count on the file changed.
 In particular, the
 .Dv NOTE_LINK
 event is reported if a subdirectory was created or deleted inside
 the directory referenced by the descriptor.
+.It Dv NOTE_OPEN
+The file referenced by the descriptor was opened.
+.It Dv NOTE_READ
+A read occurred on the file referenced by the descriptor.
 .It Dv NOTE_RENAME
 The file referenced by the descriptor was renamed.
 .It Dv NOTE_REVOKE
 Access to the file was revoked via
 .Xr revoke 2
 or the underlying file system was unmounted.
+.It Dv NOTE_WRITE
+A write occurred on the file referenced by the descriptor.
 .El
 .Pp
 On return,
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 795eac5..97ab886 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -4722,6 +4722,45 @@ vop_symlink_post(void *ap, int rc)
 		VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
 }
 
+void
+vop_open_post(void *ap, int rc)
+{
+	struct vop_open_args *a = ap;
+
+	if (!rc)
+		VFS_KNOTE_LOCKED(a->a_vp, NOTE_OPEN);
+}
+
+void
+vop_close_post(void *ap, int rc)
+{
+	struct vop_close_args *a = ap;
+
+	if (!rc && (a->a_cred != NOCRED || /* filter out revokes */
+	    (a->a_vp->v_iflag & VI_DOOMED) == 0)) {
+		VFS_KNOTE_LOCKED(a->a_vp, (a->a_fflag & FWRITE) != 0 ?
+		    NOTE_CLOSE_WRITE : NOTE_CLOSE);
+	}
+}
+
+void
+vop_read_post(void *ap, int rc)
+{
+	struct vop_read_args *a = ap;
+
+	if (!rc)
+		VFS_KNOTE_LOCKED(a->a_vp, NOTE_READ);
+}
+
+void
+vop_readdir_post(void *ap, int rc)
+{
+	struct vop_readdir_args *a = ap;
+
+	if (!rc)
+		VFS_KNOTE_LOCKED(a->a_vp, NOTE_READ);
+}
+
 static struct knlist fs_knlist;
 
 static void
diff --git a/sys/kern/vnode_if.src b/sys/kern/vnode_if.src
index 1b07a36..0350e0e 100644
--- a/sys/kern/vnode_if.src
+++ b/sys/kern/vnode_if.src
@@ -121,6 +121,7 @@ vop_mknod {
 
 
 %% open		vp	L L L
+%! open		post	vop_open_post
 
 vop_open {
 	IN struct vnode *vp;
@@ -132,6 +133,7 @@ vop_open {
 
 
 %% close	vp	L L L
+%! close	post	vop_close_post
 
 vop_close {
 	IN struct vnode *vp;
@@ -186,6 +188,7 @@ vop_markatime {
 };
 
 %% read		vp	L L L
+%! read		post	vop_read_post
 
 vop_read {
 	IN struct vnode *vp;
@@ -326,6 +329,7 @@ vop_symlink {
 
 
 %% readdir	vp	L L L
+%! readdir	post	vop_readdir_post
 
 vop_readdir {
 	IN struct vnode *vp;
diff --git a/sys/sys/event.h b/sys/sys/event.h
index 7897c81..5b54150 100644
--- a/sys/sys/event.h
+++ b/sys/sys/event.h
@@ -121,6 +121,12 @@ struct kevent {
 #define	NOTE_LINK	0x0010			/* link count changed */
 #define	NOTE_RENAME	0x0020			/* vnode was renamed */
 #define	NOTE_REVOKE	0x0040			/* vnode access was revoked */
+#define	NOTE_OPEN	0x0080			/* vnode was opened */
+#define	NOTE_CLOSE	0x0100			/* file closed, fd did not
+						   allowed write */
+#define	NOTE_CLOSE_WRITE 0x0200			/* file closed, fd did allowed
+						   write */
+#define	NOTE_READ	0x0400			/* file was read */
 
 /*
  * data/hint flags for EVFILT_PROC and EVFILT_PROCDESC, shared with userspace
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index f3ae773..df43134 100644
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -774,6 +774,7 @@ int	dead_read(struct vop_read_args *ap);
 int	dead_write(struct vop_write_args *ap);
 
 /* These are called from within the actual VOPS. */
+void	vop_close_post(void *a, int rc);
 void	vop_create_post(void *a, int rc);
 void	vop_deleteextattr_post(void *a, int rc);
 void	vop_link_post(void *a, int rc);
@@ -783,6 +784,9 @@ void	vop_lookup_post(void *a, int rc);
 void	vop_lookup_pre(void *a);
 void	vop_mkdir_post(void *a, int rc);
 void	vop_mknod_post(void *a, int rc);
+void	vop_open_post(void *a, int rc);
+void	vop_read_post(void *a, int rc);
+void	vop_readdir_post(void *a, int rc);
 void	vop_reclaim_post(void *a, int rc);
 void	vop_remove_post(void *a, int rc);
 void	vop_rename_post(void *a, int rc);