legacy/libisoburn/trunk/frontend/xorriso_broker.sh

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#!/bin/sh
# Copyright (C) 2015
# Thomas Schmitt <scdbackup@gmx.net>, libburnia-project.org
# Provided under BSD license: Use, modify, and distribute as you like.
# set -x
# ---------------------------- functions ---------------------------
usage() {
echo >&2
echo "usage: $0 "'\' >&2
echo " [-xorriso path] id_string [-dev] iso_adr [xorriso_arguments ...]" >&2
echo >&2
echo " This script looks for named pipe" >&2
echo ' /tmp/xorriso_stdin_pipe_${id_string}' >&2
echo " which is supposed to be connected to a xorriso process." >&2
echo " If not found, the stdin pipe and a stdout pipe get created" >&2
echo " and a xorriso dialog process gets started and connected." >&2
echo " Each character in id_string must match [-+:.,=@0-9A-Za-z]." >&2
echo " If iso_adr differs from the previous run with the same id_string," >&2
echo " then any changes on the previous ISO are committed as session" >&2
echo " before command -dev is performed to load the meta data of" >&2
echo " the newly addressed ISO." >&2
echo " After this is done, the optionally given xorriso_arguments" >&2
echo " are written into the stdin pipe from where xorriso will read" >&2
echo " them as commands and their parameters." >&2
echo >&2
}
# Make filenames safe for transport by wrapping them in quotes and
# escaping quotes in their text
xorriso_esc() {
echo -n "'"
echo -n "$1" | sed -e "s/'/'"'"'"'"'"'"'/g"
echo -n "'"
}
# Send one or more command lines to xorriso
xorriso_send_cmd() {
# $1 : the lines to send
# >>> is it possible to have a timeout on echo ?
if test -p "$cmd_pipe"
then
echo " $1" >"$cmd_pipe"
else
xorriso_is_running=0
return 1
fi
}
# Send command and wait for answer
xorriso_cmd_and_result() {
# $1: command line for xorriso
# $2: if not empty, grep expression for stdout
if test "$xorriso_is_running" = 0
then
return 1
fi
xorriso_send_cmd "$1" || return 1
if test -n "$2"
then
cat "$result_pipe"
else
grep "$2" <"$result_pipe"
fi
return 0
}
# ------------------------------- main -----------------------------
# Argument interpreter
if test "$#" -lt 2
then
usage "$0"
exit 1
fi
xorriso=xorriso
if test o"$1" = o"-xorriso"
then
xorriso="$2"
shift 2
fi
export xorriso_is_running=0
if test "$#" -lt 2
then
usage "$0"
exit 1
fi
id_string=$(echo "$1" | sed -e 's/[^-+:.,=@0-9A-Za-z]/_/g' )
shift 1
# Ignore second argument -dev
if test o"$1" = o"-dev"
then
shift 1
if test "$#" -lt 1
then
usage "$0"
exit 1
fi
fi
device="$1"
shift 1
# Perform the action
export cmd_pipe=/tmp/xorriso_stdin_pipe_$id_string
export result_pipe=/tmp/xorriso_stdout_pipe_$id_string
if test -p "$cmd_pipe"
then
xorriso_is_running=1
else
xorriso_is_running=0
fi
if test "$xorriso_is_running" = "0"
then
# xorriso is not started yet
# Check for xorriso version which knows command -named_pipe_loop
echo "Checking xorriso version ..." >&2
xorriso_version_req="1.3.2"
version=$("$xorriso" -version | grep '^xorriso version' |
sed -e 's/^xorriso version : //')
smallest=$( (echo "$xorriso_version_req" ; echo "$version" ) | \
sort | head -1)
if test "$smallest" = "$xorriso_version_req"
then
dummy=dummy
else
echo "$0 : FATAL : Need xorriso version >= $xorriso_version_req" >&2
echo "Found version: $version" >&2
exit 2
fi
if mknod "$cmd_pipe" p
then
echo "Created named pipe for xorriso commands: $cmd_pipe" >&2
else
echo "Failed to create named pipe for xorriso commands: $cmd_pipe" >&2
exit 3
fi
if mknod "$result_pipe" p
then
echo "Created named pipe for xorriso result channel: $result_pipe" >&2
else
echo \
"Failed to create named pipe for xorriso result channel: $result_pipe" >&2
if rm "$cmd_pipe"
then
echo "Removed named pipe for xorriso commands: $cmd_pipe" >&2
fi
exit 3
fi
echo "Starting xorriso process ..." >&2
"$xorriso" -abort_on NEVER -for_backup \
-named_pipe_loop cleanup:buffered "$cmd_pipe" "$result_pipe" "-" \
>&2 &
# (stdout is redirected to stderr, in order not to keep a pipe waiting for
# input from the still open stdout copy of the background process.
# -named_pipe_loop will disconnect xorriso result channel from stdout.)
xorriso_is_running=1
fi
# Inquire current xorriso -dev
xorriso_device=$(xorriso_cmd_and_result "-status -dev" "^-dev" | \
sed -e 's/^-dev //')
if echo " $device" | grep "^ '" >/dev/null
then
quoted="$device"
else
quoted=$(xorriso_esc "$device")
fi
if test "$xorriso_device" = "$quoted"
then
dummy=dummy
else
# Inquire the need for a -commit command
pending=$(xorriso_cmd_and_result "-changes_pending show_status" \
"^-changes_pending" \
| sed -e 's/^-changes_pending //')
if test "$pending" = "yes"
then
if xorriso_cmd_and_result "-commit"
then
dummy=dummy
else
exit 1
fi
fi
# Now change ISO filesystem
if xorriso_cmd_and_result "-dev $device"
then
xorriso_device="$device"
else
exit 1
fi
fi
test "$*" = "" && exit 0
if xorriso_cmd_and_result "$*"
then
dummy=dummy
else
exit 1
fi
exit 0