dev-mount

#!/bin/bash

set -eo pipefail

retry() {
  for i in 1 2 3 4 5; do
    if "$@"; then
      return 0
    fi
    sleep 1s
  done
  return 1
}

if [[ $# -ne 0 ]] && [[ $# -ne 1 ]]; then
  echo "usage: $0 [img-or-block]"
  exit 1
fi

if mountpoint -q /mnt; then
  echo "Something is mounted to '/mnt'. Unmount first."
  mount /mnt || true
  exit 1
fi

cleanup() {
  sync
  cd /
  umount -f /mnt/dev || true
  umount -f /mnt/proc || true
  umount -f /mnt/sys || true
  umount -f /mnt/boot || true
  umount -f /mnt || true
  kpartx -d "$DISK" || true
  losetup -d "$DISK" || true
  [[ -z "$SD_MUX" ]] || sd-mux-ctrl -v 0 --dut
}
trap cleanup EXIT

if [[ $# -eq 0 ]]; then
  if SD_MUX=$(sd-mux-ctrl -v 0 --status); then
    echo "Using SD_MUX..."
    if [[ "$SD_MUX" == "SD connected to: DUT" ]]; then
      echo "Switching SD_MUX to TS..."
      sd-mux-ctrl -v 0 --ts
      sleep 1s
    fi
  fi

  DEVICES=( $(find /dev/disk/by-id/ -name "usb-*" -not -name "*-part*") )

  if [[ "${#DEVICES[@]}" -eq 0 ]]; then
    echo "No USB devices."
    exit 1
  elif [[ "${#DEVICES[@]}" -ne 1 ]]; then
    echo "Many devices: ${DEVICES[@]}"
    exit 1
  fi

  DISK="${DEVICES[0]}"
  echo "Using '$DISK'..."
else
  DISK=$(losetup -f --show "${1}")
  kpartx -a "$DISK"
  echo "Attached '$1' to '$DISK'..."
fi

mount_part() {
  local parts="${DISK/\/dev\/loop/\/dev\/mapper\/loop}"
  local matches="$1"
  shift

  for match in $matches; do
    if [[ -b "$DISK-$match" ]]; then
      local disk="$DISK-$match"
      echo "Found '$DISK' for '$match'."
    elif MATCH=$(blkid -o device -l -t "PARTLABEL=$match" "$parts"*); then
      local disk="$MATCH"
      echo "Found '$DISK' for 'PARTLABEL=$match'."
    elif MATCH=$(blkid -o device -l -t "LABEL=$match" "$parts"*); then
      local disk="$MATCH"
      echo "Found '$DISK' for 'LABEL=$match'."
    else
      continue
    fi

    echo "Mounting '$disk' to '$@'..."
    mount "$disk" "$@"
    return 0
  done

  echo "The '$matches' does not exist."
  return 1
}

retry mount_part "part4 rootfs" /mnt
retry mount_part "part3 bootfs" /mnt/boot

mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys

cd /mnt
bash