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>
This commit is contained in:
Gilles Peskine 2020-04-23 17:33:36 +02:00
parent 2fcf04f468
commit d1b5f6f609
2 changed files with 98 additions and 31 deletions

89
programs/demo_common.sh Normal file
View file

@ -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

View file

@ -15,36 +15,15 @@
# See the License for the specific language governing permissions and # See the License for the specific language governing permissions and
# limitations under the License. # limitations under the License.
set -e -u . "${0%/*}/../demo_common.sh"
program_name="key_ladder_demo" msg <<'EOF'
program="${0%/*}/$program_name" This script demonstrates the use of the PSA cryptography interface to
files_to_clean= create a master key, derive a key from it and use that key to wrap
the derived key using an AEAD algorithm.
EOF
if [ ! -e "$program" ]; then program="${0%/*}"/key_ladder_demo
# Look for programs in the current directory and the directories above it
for dir in "." ".." "../.."; do
program="$dir/programs/psa/$program_name"
if [ -e "$program" ]; then
break
fi
done
if [ ! -e "$program" ]; then
echo "Could not find $program_name executable"
echo "If building out-of-tree, this script must be run" \
"from the project build directory."
exit 1
fi
fi
run () {
echo
echo "# $1"
shift
echo "+ $*"
"$@"
}
if [ -e master.key ]; then if [ -e master.key ]; then
echo "# Reusing the existing master.key file." echo "# Reusing the existing master.key file."
@ -68,7 +47,7 @@ run "Compare the unwrapped data with the original input." \
cmp input.txt hello_world.txt cmp input.txt hello_world.txt
files_to_clean="$files_to_clean hellow_orld.txt" files_to_clean="$files_to_clean hellow_orld.txt"
! run "Derive a different key and attempt to unwrap the data. This must fail." \ run_bad "Derive a different key and attempt to unwrap the data. This must fail." \
"$program" unwrap master=master.key input=hello_world.wrap output=hellow_orld.txt label=hellow label=orld "$program" unwrap master=master.key input=hello_world.wrap output=hellow_orld.txt label=hellow label=orld
files_to_clean="$files_to_clean hello.key" files_to_clean="$files_to_clean hello.key"
@ -79,5 +58,4 @@ run "Check that we get the same key by unwrapping data made by the other key." \
"$program" unwrap master=hello.key label=world \ "$program" unwrap master=hello.key label=world \
input=hello_world.wrap output=hello_world.txt input=hello_world.wrap output=hello_world.txt
# Cleanup cleanup
rm -f $files_to_clean