40 lines
1.1 KiB
Shell
40 lines
1.1 KiB
Shell
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#!/usr/bin/env bash
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set -euo pipefail
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[[ $# -eq 2 ]] || {
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echo "usage: clear-native-recovery-beacon.sh <disk> <clear-template>" >&2
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exit 64
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}
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disk=$1
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clear_template=$2
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[[ -f ${clear_template} ]]
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[[ $(stat -c %s "${clear_template}" 2>/dev/null || stat -f %z "${clear_template}") -eq 1024 ]]
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if [[ -b ${disk} ]]; then
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[[ ${EUID} -eq 0 ]]
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[[ $(readlink -f "${disk}") == /dev/vda ]]
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elif [[ ! -f ${disk} ]]; then
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echo "recovery beacon target is neither /dev/vda nor a test disk" >&2
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exit 65
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fi
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readback=$(mktemp)
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trap 'rm -f "${readback}"' EXIT
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dd if="${disk}" of="${readback}" bs=512 skip=68 count=2 status=none
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if cmp -s "${readback}" "${clear_template}"; then
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echo "GUANGHU_NATIVE_RECOVERY_BEACON_ALREADY_CLEAR"
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exit 0
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fi
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if ! grep -aFq 'guanghu_recovery=ubuntu' "${readback}"; then
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echo "unknown data occupies the recovery beacon sectors" >&2
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exit 65
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fi
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dd if="${clear_template}" of="${disk}" bs=512 seek=68 count=2 \
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conv=notrunc,fsync status=none
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dd if="${disk}" of="${readback}" bs=512 skip=68 count=2 status=none
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cmp "${readback}" "${clear_template}"
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echo "GUANGHU_NATIVE_RECOVERY_BEACON_CLEARED"
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