On Mon, Oct 31, 2022 at 11:11:22AM +0000, Klemens Nanni wrote:
> On Sun, Oct 16, 2022 at 05:22:57AM +0000, Klemens Nanni wrote:
> > On Sat, Oct 08, 2022 at 07:25:26PM +0000, Klemens Nanni wrote:
> > > If /usr is mounted read-only, kernel relinking fails silently without
> > > any log trace.
> > >
> > > # ksh /usr/libexec/reorder_kernel
> > > /usr/libexec/reorder_kernel[35]: cannot create
> > > /usr/share/relink/kernel/GENERIC.MP/relink.log: Read-only file system
> > >
> > > This stderr line does not show up during boot because init(8) redirects
> > > stdout/err to /dev/null, executes rc(8) which inherits this and executes
> > > reorder_kernel with both streams thus discarded.
> > >
> > > Eventually, I'd like reorder_kernel to temporarily remount $KERNEL_DIR
> > > read-write, just like rc's reorder_libs() does. I have a diff for that
> > > but would like to approach things in smaller steps.
> > >
> > > So first, defer the logfile setup after the syslog/console setup such
> > > that mkdir's failure triggers the ERR trap and users get notified:
> > >
> > > # ksh ./reorder_kernel.sh
> > > ./reorder_kernel.sh[40]: cannot create
> > > /usr/share/relink/kernel/GENERIC.MP/relink.log: Read-only file system
> > > # tail -n1 /var/log/daemon
> > > Oct 13 17:04:06 pbp reorder_kernel.sh: kernel relinking done
> > >
> > > As of now, this logs success despite actual failure because of ksh's
> > > redirection/trap bug (see mail on tech@): mkdir does not fail because
> > > the directory already exists, so `exec 1>$LOGFILE' tries to truncate but
> > > fails to trigger the ERR trap, thus hitting the non-default EXIT trap.
> > >
> > > With ksh fixed this would log
> > > Oct 13 17:04:06 pbp reorder_kernel.sh: failed -- see
> > > /usr/share/relink/kernel/GENERIC.MP/relink.log
> > > which admittedly misleading, given that creating/truncating that vary
> > > logfile is the failure reason, but it seems better than silent nothing.
> >
> > ksh's exec got fixed, so failure is now logged with this diff:
> >
> > # tail -n0 -f /var/log/messages
> > [1] 95776
> > # /usr/libexec/reorder_kernel
> > /usr/libexec/reorder_kernel[35]: cannot create
> > /usr/share/relink/kernel/GENERIC.MP/relink.log: Read-only file system
> > no log except stderr
> >
> > # ksh ./reorder_kernel.sh
> > ./reorder_kernel.sh[40]: cannot create
> > /usr/share/relink/kernel/GENERIC.MP/relink.log: Read-only file system
> > Oct 16 09:16:37 eru reorder_kernel.sh: failed -- see
> > /usr/share/relink/kernel/GENERIC.MP/relink.log
> > same "failed" message in xconsole(1)
> >
> > > It could set up an intermediate trap or truly silently bail out on
> > > read-only FFS just like it does for NFS now, but it seems best to handle
> > > ro /usr as mentioned as a follow-up step.
> >
> > Anyone?
> >
> > This diff now works as expected; not perfect but an improvement, imho.
> > Feedback? Objection? OK?
>
> No feedback so far.
>
> Supporting /usr on read-only FFS or not, I think reorder_kernel must not
> fail silently without relinking anything.
>
> There is definitely room for improvement.
Here's a trivial version that says only "reorder_kernel: failed" until
the log file is set up (which fails on read-only /usr) and says
"reorder_kernel: failed -- see $LOGFILE" once it actually logs to the
file.
Anyone?
Index: reorder_kernel.sh
===================================================================
RCS file: /cvs/src/libexec/reorder_kernel/reorder_kernel.sh,v
retrieving revision 1.11
diff -u -p -r1.11 reorder_kernel.sh
--- reorder_kernel.sh 13 May 2022 13:20:16 -0000 1.11
+++ reorder_kernel.sh 6 Nov 2022 19:43:38 -0000
@@ -30,15 +30,17 @@ LOGFILE=$KERNEL_DIR/$KERNEL/relink.log
PROGNAME=${0##*/}
SHA256=/var/db/kernel.SHA256
+# Install trap handlers to inform about success or failure via syslog.
+ERRMSG='failed'
+trap 'trap - EXIT; logger -st $PROGNAME "$ERRMSG" >/dev/console 2>&1' ERR
+trap 'logger -t $PROGNAME "kernel relinking done"' EXIT
+
# Create kernel compile dir and redirect stdout/stderr to a logfile.
mkdir -m 700 -p $KERNEL_DIR/$KERNEL
exec 1>$LOGFILE
exec 2>&1
-# Install trap handlers to inform about success or failure via syslog.
-trap 'trap - EXIT; logger -st $PROGNAME \
- "failed -- see $LOGFILE" >>/dev/console 2>&1' ERR
-trap 'logger -t $PROGNAME "kernel relinking done"' EXIT
+ERRMSG="failed -- see $LOGFILE"
if [[ -f $KERNEL_DIR.tgz ]]; then
rm -rf $KERNEL_DIR/$KERNEL/*
