Solve race-condition, return path in normal order.

A couple of stylistic nits from Bruce.

If your libc contains version 1.11 or 1.12 of getcwd.c, (ie: if
you recompiled libc one of the last couple of days):
>>> Recompile LIBC before you boot a new kernel <<<
A new libc will deal with both old and new kernels.

2 files changed, 58 insertions, 52 deletions

diff --git a/sys/kern/vfs_extattr.c b/sys/kern/vfs_extattr.c
index 01b980d..a2f1382 100644
--- a/sys/kern/vfs_extattr.c
+++ b/sys/kern/vfs_extattr.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
- * $Id: vfs_syscalls.c,v 1.68 1997/09/14 16:51:15 phk Exp $
+ * $Id: vfs_syscalls.c,v 1.69 1997/09/15 08:25:43 phk Exp $
  */
 
 /*
@@ -2765,52 +2765,55 @@ getvnode(fdp, fd, fpp)
 }
 #ifndef _SYS_SYSPROTO_H_
 struct  __getcwd_args {
-        u_char * buf;
-        u_int buflen;
+	u_char	*buf;
+	u_int	buflen;
 };
 #endif
-/* ARGSUSED */
 int
 __getcwd(p, uap, retval)
 	struct proc *p;
-	register struct __getcwd_args *uap;
+	struct __getcwd_args *uap;
 	register_t *retval;
 {
-	struct filedesc *fdp = p->p_fd;
+	struct filedesc *fdp;
 	struct vnode *vp;
 	struct namecache *ncp;
-	int i,j=0;
+	char *buf, *bp;
+	int i, j = 0, error = 0;
 
+	fdp = p->p_fd;
+	if (uap->buflen > PATH_MAX+1)
+		uap->buflen = PATH_MAX+1;
+	buf = bp = (char *)malloc(uap->buflen, M_TEMP, M_WAITOK);
+	bp += uap->buflen - 1;
+	*bp = '\0';
 	for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) {
 		if (vp->v_dd->v_id != vp->v_ddid)
-			return(ENOTDIR);
+			return (ENOTDIR);
 		ncp = TAILQ_FIRST(&vp->v_cache_dst);
 		if (!ncp)
-			return(ENOENT);
+			return (ENOENT);
 		if (ncp->nc_dvp != vp->v_dd)
-			return(EBADF);
-		for (i=ncp->nc_nlen-1; i >= 0; i--) {
-			if (uap->buflen-- < 2)
-				return(ENOMEM);
-			subyte(uap->buf, ncp->nc_name[i]);
-			uap->buf++;
+			return (EBADF);
+		for (i=ncp->nc_nlen - 1; i >= 0; i--) {
+			if (bp <= buf)
+				return (ENOMEM);
+			*--bp = ncp->nc_name[i];
 		}
-		if (uap->buflen-- < 2)
-			return(ENOMEM);
-		subyte(uap->buf, '/' );
-		uap->buf++;
+		if (bp <= buf)
+			return (ENOMEM);
+		*--bp = '/';
 		j++;
 		vp = vp->v_dd;
 		if (vp->v_flag & VROOT) 
 			vp = vp->v_mount->mnt_vnodecovered;
 	}
 	if (!j) {
-		if (uap->buflen-- < 2)
-			return(ENOMEM);
-		subyte(uap->buf, '/' );
-		uap->buf++;
+		if (bp <= buf)
+			return (ENOMEM);
+		*--bp = '/';
 	}
-	subyte(uap->buf, '\0' );
-	uap->buf++;
-	return (0);
+	error = copyout(bp, uap->buf, strlen(bp) + 1);
+	free(buf, M_TEMP);
+	return (error);
 }
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 01b980d..a2f1382 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
- * $Id: vfs_syscalls.c,v 1.68 1997/09/14 16:51:15 phk Exp $
+ * $Id: vfs_syscalls.c,v 1.69 1997/09/15 08:25:43 phk Exp $
  */
 
 /*
@@ -2765,52 +2765,55 @@ getvnode(fdp, fd, fpp)
 }
 #ifndef _SYS_SYSPROTO_H_
 struct  __getcwd_args {
-        u_char * buf;
-        u_int buflen;
+	u_char	*buf;
+	u_int	buflen;
 };
 #endif
-/* ARGSUSED */
 int
 __getcwd(p, uap, retval)
 	struct proc *p;
-	register struct __getcwd_args *uap;
+	struct __getcwd_args *uap;
 	register_t *retval;
 {
-	struct filedesc *fdp = p->p_fd;
+	struct filedesc *fdp;
 	struct vnode *vp;
 	struct namecache *ncp;
-	int i,j=0;
+	char *buf, *bp;
+	int i, j = 0, error = 0;
 
+	fdp = p->p_fd;
+	if (uap->buflen > PATH_MAX+1)
+		uap->buflen = PATH_MAX+1;
+	buf = bp = (char *)malloc(uap->buflen, M_TEMP, M_WAITOK);
+	bp += uap->buflen - 1;
+	*bp = '\0';
 	for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) {
 		if (vp->v_dd->v_id != vp->v_ddid)
-			return(ENOTDIR);
+			return (ENOTDIR);
 		ncp = TAILQ_FIRST(&vp->v_cache_dst);
 		if (!ncp)
-			return(ENOENT);
+			return (ENOENT);
 		if (ncp->nc_dvp != vp->v_dd)
-			return(EBADF);
-		for (i=ncp->nc_nlen-1; i >= 0; i--) {
-			if (uap->buflen-- < 2)
-				return(ENOMEM);
-			subyte(uap->buf, ncp->nc_name[i]);
-			uap->buf++;
+			return (EBADF);
+		for (i=ncp->nc_nlen - 1; i >= 0; i--) {
+			if (bp <= buf)
+				return (ENOMEM);
+			*--bp = ncp->nc_name[i];
 		}
-		if (uap->buflen-- < 2)
-			return(ENOMEM);
-		subyte(uap->buf, '/' );
-		uap->buf++;
+		if (bp <= buf)
+			return (ENOMEM);
+		*--bp = '/';
 		j++;
 		vp = vp->v_dd;
 		if (vp->v_flag & VROOT) 
 			vp = vp->v_mount->mnt_vnodecovered;
 	}
 	if (!j) {
-		if (uap->buflen-- < 2)
-			return(ENOMEM);
-		subyte(uap->buf, '/' );
-		uap->buf++;
+		if (bp <= buf)
+			return (ENOMEM);
+		*--bp = '/';
 	}
-	subyte(uap->buf, '\0' );
-	uap->buf++;
-	return (0);
+	error = copyout(bp, uap->buf, strlen(bp) + 1);
+	free(buf, M_TEMP);
+	return (error);
 }