Error out if someone tries to mv a mount point. Old behavior was to

move all files contained in the mounted filesystem to the dest. dir
which could be quite nasty.  Personally, I think rename(2) should
return EPERM or EINVAL instead of EXDEV.

diff --git a/bin/mv/mv.c b/bin/mv/mv.c
index d2bc283..9e089da 100644 (file)
--- a/bin/mv/mv.c
+++ b/bin/mv/mv.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mv.c,v 1.6 1997/02/02 10:16:58 tholo Exp $    */
+/*     $OpenBSD: mv.c,v 1.7 1997/03/01 20:43:51 millert Exp $  */
 /*     $NetBSD: mv.c,v 1.9 1995/03/21 09:06:52 cgd Exp $       */
 
 /*
@@ -47,7 +47,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)mv.c       8.2 (Berkeley) 4/2/94";
 #else
-static char rcsid[] = "$OpenBSD: mv.c,v 1.6 1997/02/02 10:16:58 tholo Exp $";
+static char rcsid[] = "$OpenBSD: mv.c,v 1.7 1997/03/01 20:43:51 millert Exp $";
 #endif
 #endif /* not lint */
 
@@ -55,6 +55,7 @@ static char rcsid[] = "$OpenBSD: mv.c,v 1.6 1997/02/02 10:16:58 tholo Exp $";
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
+#include <sys/mount.h>
 
 #include <err.h>
 #include <errno.h>
@@ -199,7 +200,20 @@ do_move(from, to)
        if (!rename(from, to))
                return (0);
 
-       if (errno != EXDEV) {
+       if (errno == EXDEV) {
+               struct statfs sfs;
+               char path[MAXPATHLEN];
+
+               /* Can't mv(1) a mount point. */
+               if (realpath(from, path) == NULL) {
+                       warnx("cannot resolve %s: %s", from, path);
+                       return (1);
+               }
+               if (!statfs(path, &sfs) && !strcmp(path, sfs.f_mntonname)) {
+                       warnx("cannot rename a mount point");
+                       return (1);
+               }
+       } else {
                warn("rename %s to %s", from, to);
                return (1);
        }