Add log file facility

ch3/kbuild.sh

@@ -21,6 +21,7 @@ set -euo pipefail
 name=$(basename $0)
 NUMCORES=$(nproc)
 JOBS=$((${NUMCORES}*2))
+LOG=kbuild_log
 
 CONFIGURE=1
 BUILD_INSTALL_MOD=1
@@ -42,23 +43,34 @@ set +u
 }
 set -u
 cd $1 || exit 1
+rm -f ${LOG} 2>/dev/null
+(
+date
+echo "[Logging to file ${LOG} ...]"
 echo "Version: $(head Makefile)"
+) 2>&1 | tee -a ${LOG}
 
 if [[ ${CONFIGURE} -eq 1 ]] ; then
+  (
   lsmod > /tmp/lsmod.now
   echo "[+] make LSMOD=/tmp/lsmod.now localmodconfig"
   make LSMOD=/tmp/lsmod.now localmodconfig
   echo "[+] make oldconfig"
   make oldconfig  # Update current config utilising a provided .config as base
   echo "[+] make menuconfig "
+  ) 2>&1 | tee -a ${LOG}
+  # menuconfig and tee (w/ stderr too redirected) don't seem to get along..
   make menuconfig && echo || die "menuconfig failed"
-  ls -l .config
+  ls -l .config 2>&1 | tee -a ${LOG}
 else
+  (
   echo "[-] Skipping kernel configure, just running 'make oldconfig'"
   echo "[+] make oldconfig"
   make oldconfig  # Update current config utilising a provided .config as base
+  ) 2>&1 | tee -a ${LOG}
 fi
 
+(
 # Ensure config is sane; on recent Ubuntu (~ kernel ver >= 5.13),
 # SYSTEM_REVOCATION_KEYS being enabled causes the build to fail..
 echo
@@ -66,8 +78,12 @@ echo "[+] scripts/config --disable SYSTEM_REVOCATION_KEYS"
 scripts/config --disable SYSTEM_REVOCATION_KEYS
 
 echo
+date
 echo "[+] time make -j${JOBS}"
-time make -j${JOBS} && echo || die "make <kernel> *failed*"
+time make -j${JOBS} && {
+  echo
+  date
+} || die "make <kernel> *failed*"
 [[ ! -f arch/x86/boot/bzImage ]] && die "make <kernel> *failed*? arch/x86/boot/bzImage not gen."
 
 if [[ ${BUILD_INSTALL_MOD} -eq 1 ]] ; then
@@ -84,4 +100,6 @@ sudo make install || die "*Failed*"
 echo "
 Done, reboot, select your new kernel from the bootloader menu & boot it
 (If not already done, you first need to configure GRUB to show the menu at boot)"
+date
+) 2>&1 | tee -a ${LOG}
 exit 0