First version

write_sticks.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+# Writes the contest image to USB sticks, all at the same time.
+# ERASES the listed sticks. Only USB disks are accepted.
+#
+#   sudo ./write_sticks.sh build/acpc2026.qcow2 /dev/sdb /dev/sdc ...
+#
+# The image can be the qcow2 file of build.sh (the ICPC image it is based on
+# must stay where it was during the build) or a raw .img file.
+set -uo pipefail
+
+usage() {
+    echo "Usage: sudo $0 IMAGE DEVICE [DEVICE...]" >&2
+    echo >&2
+    echo "USB disks currently attached:" >&2
+    lsblk -d -o NAME,SIZE,MODEL,TRAN | awk 'NR == 1 || $NF == "usb"' >&2
+    exit 2
+}
+
+[ $# -ge 2 ] || usage
+IMG=$1
+shift
+[ -f "$IMG" ] || { echo "Image not found: $IMG" >&2; exit 1; }
+[ "$(id -u)" -eq 0 ] || { echo "Run this script as root (sudo)." >&2; exit 1; }
+command -v qemu-img >/dev/null || { echo "qemu-img is missing." >&2; exit 1; }
+
+FORMAT=$(qemu-img info --output=json "$IMG" | python3 -I -c 'import json, sys; print(json.load(sys.stdin)["format"])')
+SIZE=$(qemu-img info --output=json "$IMG" | python3 -I -c 'import json, sys; print(json.load(sys.stdin)["virtual-size"])')
+
+echo "Image: $IMG ($FORMAT, $((SIZE / 1000000000)) GB)"
+echo
+for dev in "$@"; do
+    [ -b "$dev" ] || { echo "Not a disk: $dev" >&2; exit 1; }
+    [ "$(lsblk -dn -o TYPE "$dev")" = disk ] || { echo "Not a whole disk: $dev" >&2; exit 1; }
+    [ "$(lsblk -dn -o TRAN "$dev")" = usb ] || { echo "Not a USB disk, refused: $dev" >&2; exit 1; }
+    if lsblk -n -o MOUNTPOINTS "$dev" | grep -q '[^[:space:]]'; then
+        echo "A partition of $dev is mounted, unmount it first." >&2
+        exit 1
+    fi
+    devsize=$(blockdev --getsize64 "$dev")
+    [ "$devsize" -ge "$SIZE" ] || { echo "$dev is too small ($((devsize / 1000000000)) GB)" >&2; exit 1; }
+    echo "  $dev  $(lsblk -dn -o SIZE,MODEL "$dev")"
+done
+echo
+echo "ALL DATA ON THESE STICKS WILL BE ERASED."
+read -rp "Type ERASE to continue: " answer
+[ "$answer" = ERASE ] || { echo "Cancelled."; exit 1; }
+
+logdir=$(mktemp -d)
+write_one() {
+    local dev=$1 start=$(date +%s)
+    if qemu-img convert -n -f "$FORMAT" -O raw -t none "$IMG" "$dev" > "$logdir/$(basename "$dev").log" 2>&1; then
+        sync
+        echo "  done    $dev ($(( $(date +%s) - start )) s)"
+    else
+        echo "  FAILED  $dev (see $logdir/$(basename "$dev").log)"
+        return 1
+    fi
+}
+
+echo "Writing..."
+fail=0
+pids=()
+for dev in "$@"; do
+    write_one "$dev" &
+    pids+=($!)
+done
+for pid in "${pids[@]}"; do wait "$pid" || fail=1; done
+
+if [ $fail -eq 0 ]; then
+    echo "All sticks are written."
+    rm -rf "$logdir"
+else
+    echo "At least one stick failed. Logs: $logdir"
+fi
+exit $fail