mbedtls/programs/demo_common.sh
Gilles Peskine b2bcdc1c17 Let demo scripts declare their dependencies
Demo scripts should declare their build-time dependencies, to make
them more user-friendly. If a dependency is not met, users should see
an explicit message rather than an incomprehensible error.

Don't rely on the dependencies of individual programs because some
demo scripts use multiple programs and because some scripts might have
additional requirements.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
2023-07-25 19:36:39 +02:00

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## 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"
##
## Start with a "msg" call that explains the purpose of the script.
## Then call the "depends_on" function to ensure that all config
## dependencies are met.
##
## 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 "+ ! $*"
not "$@"
}
## config_has SYMBOL...
## Succeeds if the library configuration has all SYMBOLs set.
config_has () {
for x in "$@"; do
"$programs_dir/test/query_compile_time_config" "$x"
done
}
## depends_on SYMBOL...
## Exit if the library configuration does not have all SYMBOLs set.
depends_on () {
if ! config_has "$@"; then
cat >&2 <<EOF
This demo script requires the following configuration options to be enabled
at compile time:
$@
EOF
# Exit with a success status so that this counts as a pass for run_demos.py.
exit
fi
}
## 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
if config_has MBEDTLS_ENTROPY_NV_SEED; then
# Create a seedfile that's sufficiently long in all library configurations.
# This is necessary for programs that use randomness.
# Assume that the name of the seedfile is the default name.
files_to_clean="$files_to_clean seedfile"
dd if=/dev/urandom of=seedfile ibs=64 obs=64 count=1
fi