functions: extract fail_unseal and detect_heads_tty as shared utilities

fail_unseal() was defined identically in both unseal-hotp and unseal-totp,
differing only in the debug message string.  Move it to /etc/functions using
basename \$0 so the message still identifies the calling script.

detect_heads_tty() was copy-pasted between gui-init and gui-init-basic.
Move it to /etc/functions and replace both inline blocks with a single call.

Signed-off-by: Thierry Laurion <insurgo@riseup.net>

Author: tlaurion

initrd/bin/gui-init

@@ -17,15 +17,7 @@ export BG_COLOR_MAIN_MENU="normal"
 # fd0/1/2 with the correct console device before launching this script.
 # Fall back to /sys/class/tty/console/active (last entry = preferred console,
 # same source used by systemd and busybox cttyhack) when tty is unavailable.
-if ! HEADS_TTY=$(tty 2>/dev/null); then
-	_active=$(cat /sys/class/tty/console/active 2>/dev/null)
-	_dev="${_active##* }"
-	[ "$_dev" = "tty0" ] && _dev=$(cat /sys/class/tty/tty0/active 2>/dev/null || echo tty0)
-	HEADS_TTY="/dev/${_dev:-console}"
-fi
-unset _active _dev
-export HEADS_TTY
-export GPG_TTY="$HEADS_TTY"
+detect_heads_tty
 
 # skip_to_menu is set if the user selects "continue to the main menu" from any
 # error, so we will indeed go to the main menu even if other errors occur.  It's

initrd/bin/gui-init-basic

@@ -9,17 +9,8 @@ export BG_COLOR_MAIN_MENU="normal"
 . /etc/gui_functions
 . /tmp/config
 
-# Detect the terminal this gui-init-basic session is running on.
-# Same logic as gui-init — see comments there.
-if ! HEADS_TTY=$(tty 2>/dev/null); then
-	_active=$(cat /sys/class/tty/console/active 2>/dev/null)
-	_dev="${_active##* }"
-	[ "$_dev" = "tty0" ] && _dev=$(cat /sys/class/tty/tty0/active 2>/dev/null || echo tty0)
-	HEADS_TTY="/dev/${_dev:-console}"
-fi
-unset _active _dev
-export HEADS_TTY
-export GPG_TTY="$HEADS_TTY"
+# Detect the terminal — see detect_heads_tty in /etc/functions.
+detect_heads_tty
 
 # skip_to_menu is set if the user selects "continue to the main menu" from any
 # error, so we will indeed go to the main menu even if other errors occur.  It's

initrd/bin/unseal-hotp

@@ -6,15 +6,6 @@
 HOTP_SECRET="/tmp/secret/hotp.key"
 HOTP_COUNTER="/boot/kexec_hotp_counter"
 
-fail_unseal() {
-	TRACE_FUNC
-	if [ "$HEADS_NONFATAL_UNSEAL" = "y" ]; then
-		DEBUG "nonfatal unseal-hotp failure: $*"
-		return 1
-	fi
-	DIE "$*"
-}
-
 mount_boot_or_die() {
 	TRACE_FUNC
 	# Mount local disk if it is not already mounted

initrd/bin/unseal-totp

@@ -5,15 +5,6 @@
 
 TOTP_SECRET="/tmp/secret/totp.key"
 
-fail_unseal() {
-	TRACE_FUNC
-	if [ "$HEADS_NONFATAL_UNSEAL" = "y" ]; then
-		DEBUG "nonfatal unseal-totp failure: $*"
-		return 1
-	fi
-	DIE "$*"
-}
-
 fail_unseal_reset_required() {
 	TRACE_FUNC
 	# A TPM-side unseal failure generally indicates that reset/re-ownership is

initrd/etc/functions

@@ -366,6 +366,22 @@ LOG() {
 #   All modes: console prompt in bold white to /dev/console, plain text in debug.log
 #
 # See doc/logging.md.
+
+# detect_heads_tty - resolve the active interactive terminal and export it.
+# Sets and exports HEADS_TTY and GPG_TTY.
+# Must be called at script top-level (not inside a subshell) to take effect.
+detect_heads_tty() {
+	if ! HEADS_TTY=$(tty 2>/dev/null); then
+		local _active _dev
+		_active=$(cat /sys/class/tty/console/active 2>/dev/null)
+		_dev="${_active##* }"
+		[ "$_dev" = "tty0" ] && _dev=$(cat /sys/class/tty/tty0/active 2>/dev/null || echo tty0)
+		HEADS_TTY="/dev/${_dev:-console}"
+	fi
+	export HEADS_TTY
+	export GPG_TTY="$HEADS_TTY"
+}
+
 INPUT() {
 	TRACE_FUNC
 	local prompt="$1"
@@ -2611,6 +2627,20 @@ load_keymap() {
 	fi
 }
 
+# fail_unseal - called by unseal-hotp and unseal-totp on failure.
+# If HEADS_NONFATAL_UNSEAL=y (set by callers that handle failure themselves,
+# e.g. gui-init's integrity report), log at DEBUG and return 1 so the caller
+# can decide what to do.  Otherwise DIE, which is appropriate when the unseal
+# script is run standalone and failure is unrecoverable.
+fail_unseal() {
+	TRACE_FUNC
+	if [ "$HEADS_NONFATAL_UNSEAL" = "y" ]; then
+		DEBUG "nonfatal $(basename "$0") failure: $*"
+		return 1
+	fi
+	DIE "$*"
+}
+
 # Show an updating UTC timestamp and optional TOTP on a single refreshed line
 # until the user presses the Escape key. Returns 0 after ESC pressed.
 # Function name: show_totp_until_esc - clearly indicates this displays the