bin/140863: freebsd-update fails to check that writes will succeed, will hilarious consequences

[mark]

>Number:         140863
>Category:       bin
>Synopsis:       freebsd-update fails to check that writes will succeed, will hilarious consequences
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Nov 25 15:40:02 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     mark
>Release:        8.0-RELEASE
>Organization:
n/a
>Environment:
*broken*
>Description:
Having just completed:

# freebsd-update -r 8.0-RELEASE upgrade
# freebsd-update install

I rebooted and came back up in single-user mode to run
the final freebsd-update install command.

I mounted /usr and /var and forgot to set / to read-write.

freebsd-update gleefully installed half an update whilst spewing
errors, resulting in a system full of binaries linked to libraries
in /lib that no longer exist.

Due to other problems (mostly with sysinstall eventually doing
what it was told on the sixth reboot), it's taken most of the day
to even get this machine into a state where it can be fixed.
>How-To-Repeat:
Do the above.
>Fix:
Check mounted partitions for acceptable flags. Check for chflags
on files to be replaced.

>Release-Note:
>Audit-Trail:
>Unformatted: