From 4989de6accd3e3e1ffcdafbcae3a1f79fa9c987a Mon Sep 17 00:00:00 2001
From: Erik van der Kouwe <erik@minix3.org>
Date: Tue, 3 Aug 2010 13:57:58 +0000
Subject: [PATCH] Don't write to /etc/mtab in newroot, may be an issue on
 read-only filesystems

---
 commands/mount/mount.c      | 9 ++++++---
 commands/newroot/newroot.sh | 2 +-
 man/man1/mount.1            | 1 +
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/commands/mount/mount.c b/commands/mount/mount.c
index 305cb78a9..e459e4f2d 100644
--- a/commands/mount/mount.c
+++ b/commands/mount/mount.c
@@ -26,12 +26,13 @@ int main(argc, argv)
 int argc;
 char *argv[];
 {
-  int i, n, v = 0, mountflags;
+  int i, n, v = 0, mountflags, write_mtab;
   char **ap, *vs, *opt, *err, *type, *args, *device;
   char special[PATH_MAX+1], mounted_on[PATH_MAX+1], version[10], rw_flag[10];
 
   if (argc == 1) list();	/* just list /etc/mtab */
   mountflags = 0;
+  write_mtab = 1;
   type = NULL;
   args = NULL;
   ap = argv+1;
@@ -43,7 +44,8 @@ char *argv[];
 		case 't':	if (++i == argc) usage();
 				type = argv[i];
 				break;
-		case 'i':	mountflags |= MS_REUSE;		break;                
+		case 'i':	mountflags |= MS_REUSE;		break;
+		case 'n':	write_mtab = 0;			break;
 		case 'o':	if (++i == argc) usage();
 				args = argv[i];
 				break;
@@ -82,8 +84,9 @@ char *argv[];
   /* The mount has completed successfully. Tell the user. */
   printf("%s is read-%s mounted on %s\n",
 	argv[1], mountflags & MS_RDONLY ? "only" : "write", argv[2]);
-
+  
   /* Update /etc/mtab. */
+  if (!write_mtab) return 0;
   n = load_mtab("mount");
   if (n < 0) exit(1);		/* something is wrong. */
 
diff --git a/commands/newroot/newroot.sh b/commands/newroot/newroot.sh
index 0689fc323..530330ae5 100644
--- a/commands/newroot/newroot.sh
+++ b/commands/newroot/newroot.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
 
 # Actually, newroot is just like mounting on the root
-exec mount "$*" /
+exec mount -n "$*" /
 
diff --git a/man/man1/mount.1 b/man/man1/mount.1
index dc1f8bc76..08cf475b2 100644
--- a/man/man1/mount.1
+++ b/man/man1/mount.1
@@ -17,6 +17,7 @@ mount \- mount a file system
 .SH OPTIONS
 .FL "\-r" "File system is mounted read-only"
 .FL "\-t" "File system type"
+.FL "\-n" "Don't update mtab"
 .FL "\-o" "Options passed to FS server"
 .SH EXAMPLES
 .EX "mount /dev/fd1 /user" "Mount diskette 1 on \fI/user\fP"
-- 
2.44.0