Files
music-mirror/tools/sync-to-ipod.sh
T
Emma Thorpe 19b5c750b7 fix: accept a destination inside the device, and say so in --help
The script required the destination to be its own mount point, while the
documentation and its own usage text both told the user to pass
/media/IPOD/Music. The documented invocation was rejected.

A subdirectory is the better target, so the guard was what was wrong. --delete
is confined to it, and the device path budget is now derived from it -- the
part of the destination below its mount point -- rather than configured, so the
budget cannot disagree with where the files are actually going. The check that
matters is that the destination sits on a FAT filesystem, which is also what
catches an unmounted device: /media/IPOD/Music then resolves to the host's own
root filesystem, and emptying that is the outcome all of these guards exist to
prevent.

Three further faults found while testing the guards rather than reasoning about
them:

Stripping the trailing slash from "/" left an empty string, so the guard
refusing the host root never fired and the user got "destination is not a
directory" instead.

die() printed only its first argument, so the second half of the non-FAT
message -- the half saying to check whether the device is mounted -- was
silently dropped.

--help was not handled at all. Only -h reached the usage text, and it exited 2
to stderr, which is right for misuse and wrong for someone asking a question.
Help now goes to stdout and exits zero.

The usage text carries the guidance rather than only the README, since the
question it answers is asked at the terminal.
2026-08-25 12:21:09 +01:00

182 lines
7.0 KiB
Bash
Executable File

#!/usr/bin/env bash
# Copy the mirror onto a Rockbox device, then unmount it cleanly.
#
# The device is FAT32 with no journal, reached through the Apple firmware's
# disk mode because Rockbox's own mass storage is unreliable on an iFlash. An
# interrupted write is corruption that needs fsck.vfat from another machine, so
# this syncs and unmounts rather than leaving that to whoever pulls the cable.
#
# rsync --delete is pointed at a whole filesystem, so the checks below are the
# point of the script rather than decoration.
set -euo pipefail
usage() {
# Help goes to stdout and exits clean; misuse goes to stderr and does not.
local stream=2 code=2
if [ "${1:-}" = "help" ]; then
stream=1
code=0
fi
cat >&"$stream" <<'USAGE'
usage: sync-to-ipod.sh [options] <mirror> <destination>
-n dry run; show what would change and touch nothing
-f copy even if the FAT32 check finds unacceptable paths
-S skip submitting the Rockbox scrobbler log to Last.fm
-U leave the destination mounted afterwards
Submitting scrobbles needs LASTFM_API_KEY and LASTFM_API_SECRET; it is skipped
with a note when they are unset. Scrobbling is a write method and needs the
secret, unlike the read-only calls elsewhere in these projects.
The mirror is the directory holding the artist folders. The destination is
where those folders should end up on the device -- not the card root, unless
that is genuinely where you want them:
sync-to-ipod.sh /mnt/tank/media/music-mp3 /media/IPOD/Music
A subdirectory is the better target: --delete is confined to it, and the path
budget is derived from it, since the device's 260-character limit counts the
whole path as the device sees it. /.rockbox and the scrobbler logs are never
deleted wherever you point this.
The destination must be on a mounted FAT filesystem. That check is also what
catches an unmounted device: /media/IPOD/Music then resolves to the host's own
root filesystem, and this refuses to empty that.
Reach the device with the Apple firmware's disk mode: Menu+Select to reboot,
then immediately Select+Play. Power off afterwards by holding Play.
USAGE
exit "$code"
}
dry_run=false
force=false
unmount=true
scrobble=true
for argument in "$@"; do
[ "$argument" = "--help" ] && usage help
done
while getopts ":nfSUh" option; do
case "$option" in
n) dry_run=true ;;
f) force=true ;;
S) scrobble=false ;;
U) unmount=false ;;
h) usage help ;;
*) usage ;;
esac
done
shift $((OPTIND - 1))
[ $# -eq 2 ] || usage
# Trailing slashes are stripped for tidiness, but stripping one from "/" leaves
# an empty string, and the guard below would then never see the root it is
# there to refuse.
mirror=${1%/}
mirror=${mirror:-/}
destination=${2%/}
destination=${destination:-/}
here=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
die() {
# Every argument, not just the first: the second half of a message is
# usually the half that says what to do about it.
printf 'sync-to-ipod: %s\n' "$*" >&2
exit 1
}
[ -d "$mirror" ] || die "mirror $mirror is not a directory"
[ -n "$(ls -A "$mirror")" ] || die "mirror $mirror is empty; refusing to mirror nothing"
[ -d "$destination" ] || die "destination $destination is not a directory"
# --delete makes every one of these load-bearing. Emptying the wrong directory
# is not a mistake that announces itself.
case "$destination" in
"" | "/" | "$HOME") die "refusing to sync onto $destination" ;;
esac
[ "$(readlink -f "$mirror")" != "$(readlink -f "$destination")" ] ||
die "mirror and destination are the same directory"
# The filesystem the destination sits on, which is the check that matters: a
# subdirectory of the card is a perfectly good target, and is the better one,
# because --delete is then confined to it. Being FAT is also what proves the
# card is mounted at all -- an unmounted /media/IPOD/Music resolves to the
# host's own root filesystem, and this refuses to empty that.
filesystem=$(findmnt -no FSTYPE --target "$destination")
mounted_on=$(findmnt -no TARGET --target "$destination")
case "$filesystem" in
vfat | exfat) ;;
*)
$force ||
die "$destination is on a $filesystem filesystem, not FAT." \
"Is the device mounted? Pass -f if this is deliberate."
printf 'sync-to-ipod: destination is %s, not FAT\n' "$filesystem" >&2
;;
esac
# What the device will call this directory, which is what its path limit
# applies to. Derived rather than configured, so it cannot disagree with where
# the files are actually going.
device_prefix=${destination#"$mounted_on"}
device_prefix="/${device_prefix#/}"
printf 'sync-to-ipod: the device will see this as %s\n' "$device_prefix" >&2
if $force; then
printf 'sync-to-ipod: skipping the FAT32 check\n' >&2
elif ! python3 "$here/check_fat32.py" --device-prefix "$device_prefix" "$mirror"; then
die "the mirror holds paths FAT32 will not take; run music-mirror with --fat32-safe"
fi
# Before the copy, not after: the plays already happened, and if the transfer
# then fails there is no reason to have lost them too.
if $scrobble; then
if [ -z "${LASTFM_API_KEY:-}" ] || [ -z "${LASTFM_API_SECRET:-}" ]; then
printf 'sync-to-ipod: no Last.fm credentials, skipping the scrobbler log\n' >&2
else
scrobble_options=()
$dry_run && scrobble_options+=(--dry-run)
python3 "$here/submit_scrobbles.py" "${scrobble_options[@]}" "$destination" ||
die "submitting scrobbles failed; nothing has been copied"
fi
fi
# -rt rather than -a: owners, groups and permissions mean nothing on FAT, and
# asking for them produces a screenful of errors and a non-zero exit.
# --modify-window=2 because FAT stores mtimes to two-second resolution, without
# which every file looks changed and the whole library is copied every time.
# --delete removes tracks whose source has gone, which is the point. It would
# also remove everything on the device that the mirror does not contain -- and
# if the destination is the card root that means /.rockbox, the Rockbox install
# itself. Excluded paths are not deleted unless --delete-excluded is given,
# which it never is here.
options=(--recursive --times --delete --modify-window=2 --human-readable --info=progress2)
for owned in "/.rockbox" "/.scrobbler.log" "/.scrobbler.log.*" "/.playlist_control" \
"/System Volume Information" "/.Spotlight-V100" "/.Trashes" "/.fseventsd"; do
options+=(--exclude "$owned")
done
$dry_run && options+=(--dry-run --verbose)
printf 'sync-to-ipod: %s -> %s\n' "$mirror" "$destination" >&2
rsync "${options[@]}" "$mirror/" "$destination/"
if $dry_run; then
printf 'sync-to-ipod: dry run, nothing was written\n' >&2
exit 0
fi
sync
if $unmount; then
device=$(findmnt -no SOURCE --target "$destination")
printf 'sync-to-ipod: unmounting %s\n' "$device" >&2
if command -v udisksctl >/dev/null 2>&1; then
udisksctl unmount -b "$device"
else
umount -- "$destination"
fi
printf 'sync-to-ipod: safe to disconnect\n' >&2
else
printf 'sync-to-ipod: still mounted; unmount before disconnecting\n' >&2
fi