113 lines
3.2 KiB
Bash
Executable file
113 lines
3.2 KiB
Bash
Executable file
#!/usr/bin/env bash
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if [[ -z "${TARGET_UID}" ]]; then
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echo "Error: The TARGET_UID environment variable was not specified.";
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exit 1;
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fi
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if [[ -z "${TARGET_GID}" ]]; then
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echo "Error: The TARGET_GID environment variable was not specified.";
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exit 1;
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fi
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if [[ "${EUID}" -ne 0 ]]; then
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echo "Error: This Docker container must run as root because fetchmail is a pain, and to allow customisation of the target UID/GID (although all possible actions are run as non-root users)";
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exit 1;
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fi
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dir_mail_root="/tmp/maildir";
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dir_newmail="${dir_mail_root}/Mail/new";
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target_dir="/mnt/output";
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fetchmail_uid="$(id -u "fetchmail")";
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fetchmail_gid="$(id -g "fetchmail")";
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temp_dir="$(mktemp --tmpdir -d "imap-download-XXXXXXX")";
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on_exit() {
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rm -rf "${temp_dir}";
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}
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trap on_exit EXIT;
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run_as_user() {
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run_as_uid="${1}"; shift;
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run_as_gid="${1}"; shift;
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if [[ -z "${run_as_uid}" ]]; then
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echo "run_as_user: No target UID specified.";
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return 1;
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fi
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if [[ -z "${run_as_gid}" ]]; then
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echo "run_as_user: No target GID specified.";
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return 2;
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fi
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# Ref https://github.com/SinusBot/docker/pull/40
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# WORKAROUND for `setpriv: libcap-ng is too old for "all" caps`, previously "-all" was used here
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# create a list to drop all capabilities supported by current kernel
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cap_prefix="-cap_";
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caps="$cap_prefix$(seq -s ",$cap_prefix" 0 "$(cat /proc/sys/kernel/cap_last_cap)")";
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setpriv --inh-caps="${caps}" --reuid "${run_as_uid}" --clear-groups --regid "${run_as_gid}" "$@";
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return "$?";
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}
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do_fetchmail() {
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log_msg "Starting fetchmail";
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while :; do
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run_as_user "${fetchmail_uid}" "${fetchmail_gid}" fetchmail --mda "/usr/bin/procmail -m /srv/procmail.conf";
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exit_code="$?";
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if [[ "$exit_code" -eq 127 ]]; then
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log_msg "setpriv failed, exiting with code 127";
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exit 127;
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fi
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log_msg "Fetchmail exited with code ${exit_code}, sleeping 60 seconds";
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sleep 60
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done
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}
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log_msg() {
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echo "$(date -u +"%Y-%m-%d %H:%M:%S") imap-download: $*";
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}
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mkdir -p "${dir_newmail}";
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chown -R "${fetchmail_uid}:${fetchmail_gid}" "${dir_mail_root}";
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do_attachments() {
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while :; do # : = infinite loop
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# Wait for an update
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# inotifywait's non-0 exit code forces an exit for some reason :-/
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inotifywait -qr --event create --format '%:e %f' "${dir_newmail}";
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while read -r filename; do
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log_msg "Processing email ${filename}";
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# Move the email to a temporary directory for processing
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mv "${filename}" "${temp_dir}";
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filepath_temp="${temp_dir}/$(basename "${filename}")"
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# Unpack the attachments
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munpack -C "${temp_dir}" "${filepath_temp}";
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# Delete the original email file and any description files
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rm "${filepath_temp}";
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find "${temp_dir}" -iname '*.desc' -delete;
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chown -R "${TARGET_UID}:${TARGET_GID}" "${temp_dir}";
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chmod -R a=rX,ug+w "${temp_dir}";
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ls -lahR "${temp_dir}";
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# Move the attachment files to the output directory
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while read -r attachment; do
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log_msg "Extracted attachment ${attachment}";
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chmod 0775 "${attachment}";
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run_as_user "${TARGET_UID}" "${TARGET_GID}" mv "${attachment}" "${target_dir}";
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done < <(find "${temp_dir}" -type f);
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done < <(find "${dir_newmail}" -type f);
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done
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}
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do_fetchmail &
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do_attachments
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