Move common code of demo scripts into a library
The new file programs/demo_common.sh contains initialization code,
utility functions and cleanup code meant to be used by all demo
scripts written in sh.
Initial features:
* msg: Display a message.
* run, run_bad: Run a command, visibly.
* $root_dir, $programs_dir: location of the mbedtls source tree.
* $files_to_clean: files that are cleaned up on exit.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/demo_common.sh b/programs/demo_common.sh
new file mode 100644
index 0000000..91b33b9
--- /dev/null
+++ b/programs/demo_common.sh
@@ -0,0 +1,89 @@
+## Common shell functions used by demo scripts programs/*/*.sh.
+
+## How to write a demo script
+## ==========================
+##
+## Include this file near the top of each demo script:
+## . "${0%/*}/../demo_common.sh"
+##
+## As the last thing in the script, call the cleanup function.
+##
+## You can use the functions and variables described below.
+
+set -e -u
+
+## $root_dir is the root directory of the Mbed TLS source tree.
+root_dir="${0%/*}"
+n=4 # limit the search depth
+while ! [ -d "$root_dir/programs" ] || ! [ -d "$root_dir/library" ]; do
+ if [ $n -eq 0 ]; then
+ echo >&2 "This doesn't seem to be an Mbed TLS source tree."
+ exit 125
+ fi
+ n=$((n - 1))
+ case $root_dir in
+ .) root_dir="..";;
+ ..|?*/..) root_dir="$root_dir/..";;
+ ?*/*) root_dir="${root_dir%/*}";;
+ /*) root_dir="/";;
+ *) root_dir=".";;
+ esac
+done
+
+## $programs_dir is the directory containing the sample programs.
+programs_dir="$root_dir/programs"
+
+## msg LINE...
+## msg <TEXT_ORIGIN
+## Display an informational message.
+msg () {
+ if [ $# -eq 0 ]; then
+ sed 's/^/# /'
+ else
+ for x in "$@"; do
+ echo "# $x"
+ done
+ fi
+}
+
+## run "Message" COMMAND ARGUMENT...
+## Display the message, then run COMMAND with the specified arguments.
+run () {
+ echo
+ echo "# $1"
+ shift
+ echo "+ $*"
+ "$@"
+}
+
+## Like '!', but stop on failure with 'set -e'
+not () {
+ if "$@"; then false; fi
+}
+
+## run_bad "Message" COMMAND ARGUMENT...
+## Like run, but the command is expected to fail.
+run_bad () {
+ echo
+ echo "$1 This must fail."
+ shift
+ echo "+ ! $*"
+ not "$@"
+}
+
+## Add the names of files to clean up to this whitespace-separated variable.
+## The file names must not contain whitespace characters.
+files_to_clean=
+
+
+
+################################################################
+## End of the public interfaces. Code beyond this point is not
+## meant to be called directly from a demo script.
+
+cleanup () {
+ rm -f -- $files_to_clean
+}
+trap 'cleanup; trap - HUP; kill -HUP $$' HUP
+trap 'cleanup; trap - INT; kill -INT $$' INT
+trap 'cleanup; trap - TERM; kill -TERM $$' TERM