etc/functions: add wait_for_usb_devices helper to fix gpg --card-status failing because race condition without sleep

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

Author: tlaurion

initrd/etc/functions

@@ -195,13 +195,16 @@ confirm_gpg_card() {
 
 	# setup the USB so we can reach the USB Security dongle's OpenPGP smartcard
 	enable_usb
+	# Wait for USB enumeration before accessing GPG card to avoid race condition
+	wait_for_usb_devices
 
 	echo -e "\nVerifying presence of GPG card...\n"
 	# ensure we don't exit without retrying
 	errexit=$(set -o | grep errexit | awk '{print $2}')
 	set +e
-	gpg_output=$(gpg --card-status 2>&1)
-	if [ $? -ne 0 ]; then
+	DEBUG "Attempting gpg card detection (bounded wait)"
+	if ! wait_for_gpg_card; then
+		DEBUG "GPG card access failed with output: $gpg_output"
 		# prompt for reinsertion and try a second time
 		read -n1 -r -p \
 			"Can't access GPG key; remove and reinsert, then press Enter to retry. " \
@@ -211,8 +214,10 @@ confirm_gpg_card() {
 			set -e
 		fi
 		# retry card status
-		gpg_output=$(gpg --card-status 2>&1) ||
+		DEBUG "Retrying gpg --card-status after reinsertion (bounded wait)"
+		wait_for_gpg_card ||
 			die "gpg card read failed"
+		DEBUG "Retry succeeded"
 	fi
 
 	# Extract and display GPG PIN retry counters
@@ -419,7 +424,89 @@ enable_usb() {
 	insmod /lib/modules/ehci-pci.ko || die "ehci_pci: module load failed"
 	insmod /lib/modules/xhci-hcd.ko || die "xhci_hcd: module load failed"
 	insmod /lib/modules/xhci-pci.ko || die "xhci_pci: module load failed"
+}
+
+# Wait for USB bus enumeration to complete after enable_usb() loads modules.
+# Uses time-bounded polling (max 2s) to avoid race conditions where device
+# nodes haven't been created yet. No hardcoded sleep - checks actual readiness.
+# Waits for actual USB peripheral devices (e.g., 1-1, 5-3), not just hubs/controllers.
+wait_for_usb_devices() {
+	TRACE_FUNC
+	if [ ! -d /sys/bus/usb/devices ] || [ ! -r /proc/uptime ]; then
+		DEBUG "USB sysfs or uptime not available, skipping wait"
+		return
+	fi
+
+	local start now elapsed
+	start=$(awk '{print $1}' /proc/uptime)
+	DEBUG "Waiting for USB peripheral devices (not just hubs) - max 2s timeout"
+
+	local iteration=0
+	while :; do
+		iteration=$((iteration + 1))
+		
+		# Check for actual USB peripheral devices (format: bus-port like 1-1, 5-3)
+		# Root hubs are named usb1, usb2, etc. - we want devices downstream from them
+		# Pattern: /sys/bus/usb/devices/[0-9]*-[0-9]*/idVendor (e.g., 1-1, 5-3.2)
+		local peripheral_count=0
+		if [ -d /sys/bus/usb/devices ]; then
+			# Count devices matching bus-port pattern (not usb* root hubs)
+			for dev in /sys/bus/usb/devices/*-*/idVendor; do
+				if [ -r "$dev" ]; then
+					peripheral_count=$((peripheral_count + 1))
+				fi
+			done
+		fi
+		
+		now=$(awk '{print $1}' /proc/uptime)
+		elapsed=$(awk -v s="$start" -v n="$now" 'BEGIN{printf "%.3f", n - s}')
+		
+		if [ $peripheral_count -gt 0 ]; then
+			DEBUG "USB peripheral devices ready after ${elapsed}s (iteration $iteration): found $peripheral_count device(s)"
+			return
+		fi
+		
+		# Timeout after 2 seconds
+		if awk -v s="$start" -v n="$now" 'BEGIN{exit (n - s > 2.0) ? 0 : 1}'; then
+			DEBUG "USB wait timeout at ${elapsed}s (iter $iteration): only found $peripheral_count peripheral device(s)"
+			return
+		fi
+	done
+}
 
+# Wait for gpg --card-status to succeed (bounded, no sleep).
+# Sets global gpg_output with the last command output.
+wait_for_gpg_card() {
+	TRACE_FUNC
+	if [ ! -r /proc/uptime ]; then
+		gpg_output=$(gpg --card-status 2>&1)
+		return $?
+	fi
+
+	local start now elapsed
+	start=$(awk '{print $1}' /proc/uptime)
+	local attempt=0
+	while :; do
+		attempt=$((attempt + 1))
+		gpg_output=$(gpg --card-status 2>&1)
+		if [ $? -eq 0 ]; then
+			now=$(awk '{print $1}' /proc/uptime)
+			elapsed=$(awk -v s="$start" -v n="$now" 'BEGIN{printf "%.3f", n - s}')
+			DEBUG "gpg --card-status succeeded after ${elapsed}s (attempt $attempt)"
+			return 0
+		fi
+
+		now=$(awk '{print $1}' /proc/uptime)
+		elapsed=$(awk -v s="$start" -v n="$now" 'BEGIN{printf "%.3f", n - s}')
+		if awk -v s="$start" -v n="$now" 'BEGIN{exit (n - s > 2.0) ? 0 : 1}'; then
+			DEBUG "gpg --card-status timeout at ${elapsed}s (attempt $attempt)"
+			return 1
+		fi
+	done
+}
+
+enable_usb_keyboard() {
+	TRACE_FUNC
 	# For resiliency, test CONFIG_USB_KEYBOARD_REQUIRED explicitly rather
 	# than having it imply CONFIG_USER_USB_KEYBOARD at build time.
 	# Otherwise, if a user got CONFIG_USER_USB_KEYBOARD=n in their