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.
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.
Thoughts? (none of this should go in before ksh gets fixed)
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 8 Oct 2022 18:59:07 -0000
@@ -30,15 +30,15 @@ LOGFILE=$KERNEL_DIR/$KERNEL/relink.log
PROGNAME=${0##*/}
SHA256=/var/db/kernel.SHA256
-# 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
+
+# Create kernel compile dir and redirect stdout/stderr to a logfile.
+mkdir -m 700 -p $KERNEL_DIR/$KERNEL
+exec 1>$LOGFILE
+exec 2>&1
if [[ -f $KERNEL_DIR.tgz ]]; then
rm -rf $KERNEL_DIR/$KERNEL/*
