From tholo: Do not do strict POSIX offset checking on character devices.

This fixes the problem of not being able to read kernel virtual memory on
the alpha, thus breaking things like ps etc.

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 46df453..ebfa027 100644 (file)
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vfs_syscalls.c,v 1.23 1997/02/14 17:20:09 deraadt Exp $       */
+/*     $OpenBSD: vfs_syscalls.c,v 1.24 1997/02/26 16:38:20 niklas Exp $        */
 /*     $NetBSD: vfs_syscalls.c,v 1.71 1996/04/23 10:29:02 mycroft Exp $        */
 
 /*
@@ -1166,7 +1166,7 @@ sys_lseek(p, v, retval)
        register struct file *fp;
        struct vattr vattr;
        struct vnode *vp;
-       int error;
+       int error, special;
 
        if ((u_int)SCARG(uap, fd) >= fdp->fd_nfiles ||
            (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL)
@@ -1176,9 +1176,13 @@ sys_lseek(p, v, retval)
        vp = (struct vnode *)fp->f_data;
        if (vp->v_type == VFIFO)
                return (ESPIPE);
+       if (vp->v_type == VCHR)
+               special = 1;
+       else
+               special = 0;
        switch (SCARG(uap, whence)) {
        case L_INCR:
-               if (fp->f_offset + SCARG(uap, offset) < 0)
+               if (!special && fp->f_offset + SCARG(uap, offset) < 0)
                        return (EINVAL);
                fp->f_offset += SCARG(uap, offset);
                break;
@@ -1187,12 +1191,12 @@ sys_lseek(p, v, retval)
                                    cred, p);
                if (error)
                        return (error);
-               if ((off_t)vattr.va_size + SCARG(uap, offset) < 0)
+               if (!special && (off_t)vattr.va_size + SCARG(uap, offset) < 0)
                        return (EINVAL);
                fp->f_offset = SCARG(uap, offset) + vattr.va_size;
                break;
        case L_SET:
-               if (SCARG(uap, offset) < 0)
+               if (!special && SCARG(uap, offset) < 0)
                        return (EINVAL);
                fp->f_offset = SCARG(uap, offset);
                break;