Make the seek a method of the struct fileops.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation

1 files changed, 71 insertions, 0 deletions

diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 59b8995..c53030a 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/disk.h>
 #include <sys/fcntl.h>
 #include <sys/file.h>
 #include <sys/kdb.h>
@@ -101,6 +102,7 @@ struct 	fileops vnops = {
 	.fo_chmod = vn_chmod,
 	.fo_chown = vn_chown,
 	.fo_sendfile = vn_sendfile,
+	.fo_seek = vn_seek,
 	.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
 };
 
@@ -2010,3 +2012,72 @@ unlock:
 		*off = noff;
 	return (error);
 }
+
+int
+vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
+{
+	struct ucred *cred;
+	struct vnode *vp;
+	struct vattr vattr;
+	off_t foffset, size;
+	int error, noneg;
+
+	cred = td->td_ucred;
+	vp = fp->f_vnode;
+	foffset = foffset_lock(fp, 0);
+	noneg = (vp->v_type != VCHR);
+	error = 0;
+	switch (whence) {
+	case L_INCR:
+		if (noneg &&
+		    (foffset < 0 ||
+		    (offset > 0 && foffset > OFF_MAX - offset))) {
+			error = EOVERFLOW;
+			break;
+		}
+		offset += foffset;
+		break;
+	case L_XTND:
+		vn_lock(vp, LK_SHARED | LK_RETRY);
+		error = VOP_GETATTR(vp, &vattr, cred);
+		VOP_UNLOCK(vp, 0);
+		if (error)
+			break;
+
+		/*
+		 * If the file references a disk device, then fetch
+		 * the media size and use that to determine the ending
+		 * offset.
+		 */
+		if (vattr.va_size == 0 && vp->v_type == VCHR &&
+		    fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
+			vattr.va_size = size;
+		if (noneg &&
+		    (vattr.va_size > OFF_MAX ||
+		    (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
+			error = EOVERFLOW;
+			break;
+		}
+		offset += vattr.va_size;
+		break;
+	case L_SET:
+		break;
+	case SEEK_DATA:
+		error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
+		break;
+	case SEEK_HOLE:
+		error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
+		break;
+	default:
+		error = EINVAL;
+	}
+	if (error == 0 && noneg && offset < 0)
+		error = EINVAL;
+	if (error != 0)
+		goto drop;
+	VFS_KNOTE_UNLOCKED(vp, 0);
+	*(off_t *)(td->td_retval) = offset;
+drop:
+	foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
+	return (error);
+}