safer, simpler error handling in lbmk

in shell scripts, a function named the same as a program included in
the $PATH will override that program. for example, you could make a
function called ls() and this would override the standand "ls".

in lbmk, a part of it was first trying to run the "fail" command,
deferring to "err", because some scripts call fail() which does
some minor cleanup before calling err.

in most cases, fail() is not defined, and it's possible that the user
could have a program called "fail" in their $PATH, the behaviour of
which we could not determine, and it could have disastrous effects.

lbmk error handling has been re-engineered in such a way that the
err function is defined in a variable, which defaults to err_ which
calls err_, so defined under include/err.sh.

in functions that require cleanup prior to error handling, a fail()
function is still defined, and err is overridden, thus:

err="fail"

this change has made xx_() obsolete, so now only x_ is used. the x_
function is a wrapper that can be used to run a command and exit with
non-zero status (from lbmk) if the command fails. the xx_ command
did the same thing, but called fail() which would have called err();
now everything is $err

example:

	rm -f "$filename" || err "could not delete file"

this would now be:

	rm -f "$filename" || $err "could not delete file"

overriding of err= must be done *after* including err.sh. for
example:

err="fail"
. "include/err.sh"

^ this is wrong. instead, one must do:

. "include/err.sh"
err="fail"

this is because err is set as a global variable under err.sh

the new error handling is much cleaner, and safer. it also reduces
the chance of mistakes such as: calling err when you meant to
call fail. this is because the standard way is now to call $err,
so you set err="fail" at the top of the script and all is well.

Signed-off-by: Leah Rowe <leah@libreboot.org>

2 files changed, 21 insertions, 21 deletions

diff --git a/script/build/roms b/script/build/roms
index 9e7c69ee..a90e1daa 100755
--- a/script/build/roms
+++ b/script/build/roms
@@ -49,7 +49,7 @@ main()
 	done
 
 	[ "${all}" != "y" ] || boards=$(items config/coreboot) || \
-	    err "Cannot generate list of boards for building"
+	    $err "Cannot generate list of boards for building"
 
 	for x in ${boards}; do
 		eval "$(setvars "n" ${pv}) $(setvars "" ${v})"
@@ -62,7 +62,7 @@ main()
 		targets="* bin/${board}\n${targets}"
 	done
 
-	[ -z "${targets}" ] && err "No ROM images were compiled"
+	[ -z "${targets}" ] && $err "No ROM images were compiled"
 	printf "\nROM images available in these directories:\n"
 	eval "printf \"${targets}\""
 	printf "^^ ROM images available in these directories.\n\n"
@@ -74,7 +74,7 @@ configure_target()
 {
 	targetdir="${cfgsdir}/${board}"
 	[ -f "${targetdir}/target.cfg" ] || \
-		err "Missing target.cfg for target: ${board}"
+		$err "Missing target.cfg for target: ${board}"
 
 	# Override the above defaults using target.cfg
 	. "${targetdir}/target.cfg"
@@ -84,7 +84,7 @@ configure_target()
 	    && [ "${grub_scan_disk}" != "ahci" ] && \
 		grub_scan_disk="both"
 
-	[ -z "$tree" ] && err "$board: tree not defined"
+	[ -z "$tree" ] && $err "$board: tree not defined"
 
 	[ "${payload_memtest}" != "y" ] && payload_memtest="n"
 	[ "${payload_grub_withseabios}" = "y" ] && payload_grub="y"
@@ -101,7 +101,7 @@ configure_target()
 	    [ "${payload_uboot}" != "y" ] && \
 		for configfile in "${targetdir}/config/"*; do
 			[ -e "${configfile}" ] || continue
-			err "target '${board}' defines no payload"
+			$err "target '${board}' defines no payload"
 		done
 
 	[ "$payload_uboot" != "n" ] && [ "$payload_uboot" != "y" ] && \
@@ -149,7 +149,7 @@ build_grub_payload()
 		keymaps="${keymaps} ${keymapfile}"
 	done
 	[ -z "$_keyboard" ] || [ -f "$grubcfgsdir/keymap/$_keyboard.gkb" ] || \
-		err "build_grub_payload: $_keyboard layout not defined"
+		$err "build_grub_payload: $_keyboard layout not defined"
 	[ -n "$_keyboard" ] && keymaps="${grubcfgsdir}/keymap/${_keyboard}.gkb"
 	[ -f "$grubelf" ] && return 0
 	[ -f "src/grub/grub-mkstandalone" ] || x_ ./update trees -b grub
@@ -164,7 +164,7 @@ build_grub_payload()
 	    --install-modules="${grub_install_modules}" \
 	    "/boot/grub/grub.cfg=${grubcfgsdir}/config/grub_memdisk.cfg" \
 	    "/boot/grub/grub_default.cfg=${grubcfgsdir}/config/grub.cfg" || \
-	    err "could not generate grub.elf"
+	    $err "could not generate grub.elf"
 }
 
 build_uboot_payload()
@@ -175,12 +175,12 @@ build_uboot_payload()
 	[ ! -f "${ubootelf}" ] && [ -f "${ubdir}/u-boot" ] && \
 		ubootelf="${ubdir}/u-boot"
 	[ -f "${ubootelf}" ] && return 0
-	err "Can't find u-boot build for board, $board";
+	$err "Can't find u-boot build for board, $board";
 }
 
 build_target_mainboard()
 {
-	rm -f "${romdir}/"* || err "!prepare, rm files, ${romdir}"
+	rm -f "${romdir}/"* || $err "!prepare, rm files, ${romdir}"
 
 	for x in "normal" "vgarom" "libgfxinit"; do
 		initmode="${x}"
@@ -237,7 +237,7 @@ build_seabios_roms()
 		x_ build_grub_roms "${t}" "seabios_withgrub"
 	else
 		t=$(mkSeabiosRom "${cbrom}" "fallback/payload") || \
-		    err "build_seabios_roms: cannot build tmprom"
+		    $err "build_seabios_roms: cannot build tmprom"
 		newrom="${romdir}/seabios_${board}_${initmode}_${displaymode}"
 		[ "${initmode}" = "normal" ] && newrom="${romdir}/seabios" \
 			&& newrom="${newrom}_${board}_${initmode}"
@@ -256,13 +256,13 @@ build_grub_roms()
 	if [ "$payload1" = "grub" ] && [ "$payload_grub_withseabios" = "y" ]
 	then
 		_tmpmvrom=$(mkSeabiosRom "$tmprom" "seabios.elf") || \
-		    err "build_grub_roms 1 $board: can't build tmprom"
+		    $err "build_grub_roms 1 $board: can't build tmprom"
 		x_ mv "$_tmpmvrom" "$tmprom"
 	elif [ "$payload1" != "grub" ] && [ "$payload_seabios_withgrub" = "y" ]
 	then
 		grub_cbfs="img/grub2"
 		_tmpmvrom=$(mkSeabiosRom "$tmprom" fallback/payload) || \
-		    err "build_grub_roms 2 $board: can't build tmprom"
+		    $err "build_grub_roms 2 $board: can't build tmprom"
 		x_ mv "$_tmpmvrom" "$tmprom"
 	fi
 
@@ -276,16 +276,16 @@ build_grub_roms()
 		backgroundfile="config/grub/background/${grub_background}"
 		"${cbfstool}" "${tmprom}" add -f ${backgroundfile} \
 		    -n background.png -t raw || \
-		    err "insert background, ${backgroundfile}"
+		    $err "insert background, ${backgroundfile}"
 	fi
 
 	tmpcfg=$(mktemp -t coreboot_rom.XXXXXXXXXX)
 	printf "set grub_scan_disk=\"%s\"\n" "$grub_scan_disk" >"$tmpcfg" \
-	    || err "set grub_scandisk, $grub_scan_disk, $tmpcfg"
+	    || $err "set grub_scandisk, $grub_scan_disk, $tmpcfg"
 	[ "${grub_scan_disk}" = "both" ] || \
 	    x_ "$cbfstool" "$tmprom" add -f "$tmpcfg" -n scan.cfg -t raw
 	printf "set timeout=%s\n" "${grub_timeout}" > "${tmpcfg}" || \
-	    err "set timeout, ${grub_timeout}, ${tmpcfg}"
+	    $err "set timeout, ${grub_timeout}, ${tmpcfg}"
 	[ -z "${grub_timeout}" ] || x_ "${cbfstool}" "${tmprom}" add \
 	    -f "${tmpcfg}" -n timeout.cfg -t raw
 	x_ rm -f "${tmpcfg}"
@@ -344,7 +344,7 @@ mkSeabiosGrubonlyRom()
 	tmpbootorder=$(mktemp -t coreboot_rom.XXXXXXXXXX)
 
 	# only load grub, by inserting a custom bootorder file
-	printf "/rom@img/grub2\n" > "$tmpbootorder" || err "printf bootorder"
+	printf "/rom@img/grub2\n" > "$tmpbootorder" || $err "printf bootorder"
 	x_ "${cbfstool}" "${_grubrom}" \
 	    add -f "${tmpbootorder}" -n bootorder -t raw
 	x_ rm -f "${tmpbootorder}"
@@ -356,7 +356,7 @@ mkSeabiosGrubonlyRom()
 build_uboot_roms()
 {
 	tmprom=$(mkUbootRom "${cbrom}" "fallback/payload") || \
-	    err "build_uboot_roms $board: could not create tmprom"
+	    $err "build_uboot_roms $board: could not create tmprom"
 	newrom="${romdir}/uboot_payload_${board}_${initmode}_${displaymode}.rom"
 	x_ moverom "${tmprom}" "${newrom}"
 	x_ rm -f "${tmprom}"
@@ -370,7 +370,7 @@ mkUbootRom() {
 	_ubdir="elf/u-boot/${board}/${uboot_config}"
 	_ubootelf="${_ubdir}/u-boot.elf"
 	[ -f "${_ubootelf}" ] || _ubootelf="${_ubdir}/u-boot"
-	[ -f "$_ubootelf" ] || err "mkUbootRom: $board: cant find u-boot"
+	[ -f "$_ubootelf" ] || $err "mkUbootRom: $board: cant find u-boot"
 
 	tmprom=$(mktemp -t coreboot_rom.XXXXXXXXXX)
 
diff --git a/script/build/serprog b/script/build/serprog
index 8b003add..ea2c02bf 100755
--- a/script/build/serprog
+++ b/script/build/serprog
@@ -17,8 +17,8 @@ usage="usage: ./build firmware serprog <rp2040|stm32> [board]"
 
 main()
 {
-	[ -z "${1+x}" ] && err "${usage}"
-	[ "$1" != "rp2040" ] && [ "$1" != "stm32" ] && err "$usage"
+	[ -z "${1+x}" ] && $err "${usage}"
+	[ "$1" != "rp2040" ] && [ "$1" != "stm32" ] && $err "$usage"
 	if [ "${1}" = "rp2040" ]; then
 		boards_dir=${pico_sdk_dir}/src/boards/include/boards
 		[ -d "$pico_src_dir" ] || x_ ./update trees -f "pico-serprog"
@@ -71,7 +71,7 @@ print_boards()
 
 list_boards()
 {
-	basename -a -s .h "${1}/"*.h || err "list_boards $1: can't list boards"
+	basename -a -s .h "${1}/"*.h || $err "list_boards $1: can't list boards"
 }
 
 main $@