Use OPENSSL everywhere, not OPENSSL_CMD

These variables were both uses to select the default version of OpenSSL
to use for tests:
- when running compat.sh or ssl-opt.sh directly, OPENSSL_CMD was used;
- when running all.sh, OPENSSL was used.

This caused surprising situations if you had one but not the other set
in your environment. For example I used to have OPENSSL_CMD set but not
OPENSSL, so ssl-opt.sh was failing in some all.sh components but passing
when I ran it manually in the same configuration and build, a rather
unpleasant experience.

The natural name would be OPENSSL, and that's what set in the Docker
images used by the CI. However back in the 1.3.x days, that name was
already used in library/Makefile, so it was preferable to pick a
different one, hence OPENSSL_CMD. However the build system has not been
using this name since at least Mbed TLS 2.0.0, so it's now free for use
again (as demonstrated by the fact that it's been set in the CI without
causing any trouble).

So, unify things and use OPENSSL everywhere. Just leave an error message
for the benefit of developers which might have OPENSSL_CMD, not OPENSSL,
set in their environment from the old days.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>

tests/ssl-opt.sh

@@ -46,11 +46,22 @@ fi
 : ${P_CLI:=../programs/ssl/ssl_client2}
 : ${P_PXY:=../programs/test/udp_proxy}
 : ${P_QUERY:=../programs/test/query_compile_time_config}
-: ${OPENSSL_CMD:=openssl} # OPENSSL would conflict with the build system
+: ${OPENSSL:=openssl}
 : ${GNUTLS_CLI:=gnutls-cli}
 : ${GNUTLS_SERV:=gnutls-serv}
 : ${PERL:=perl}
 
+# The OPENSSL variable used to be OPENSSL_CMD for historical reasons.
+# To help the migration, error out if the old variable is set,
+# but only if it has a different value than the new one.
+if [ "${OPENSSL_CMD+set}" = set ]; then
+    # the variable is set, we can now check its value
+    if [ "$OPENSSL_CMD" != "$OPENSSL" ]; then
+        echo "Please use OPENSSL instead of OPENSSL_CMD." >&2
+        exit 125
+    fi
+fi
+
 guess_config_name() {
     if git diff --quiet ../include/mbedtls/mbedtls_config.h 2>/dev/null; then
         echo "default"
@@ -62,8 +73,8 @@ guess_config_name() {
 : ${MBEDTLS_TEST_CONFIGURATION:="$(guess_config_name)"}
 : ${MBEDTLS_TEST_PLATFORM:="$(uname -s | tr -c \\n0-9A-Za-z _)-$(uname -m | tr -c \\n0-9A-Za-z _)"}
 
-O_SRV="$OPENSSL_CMD s_server -www -cert data_files/server5.crt -key data_files/server5.key"
-O_CLI="echo 'GET / HTTP/1.0' | $OPENSSL_CMD s_client"
+O_SRV="$OPENSSL s_server -www -cert data_files/server5.crt -key data_files/server5.key"
+O_CLI="echo 'GET / HTTP/1.0' | $OPENSSL s_client"
 G_SRV="$GNUTLS_SERV --x509certfile data_files/server5.crt --x509keyfile data_files/server5.key"
 G_CLI="echo 'GET / HTTP/1.0' | $GNUTLS_CLI --x509cafile data_files/test-ca_cat12.crt"
 TCP_CLIENT="$PERL scripts/tcp_client.pl"
@@ -509,7 +520,7 @@ requires_hash_alg() {
 # skip next test if OpenSSL doesn't support FALLBACK_SCSV
 requires_openssl_with_fallback_scsv() {
     if [ -z "${OPENSSL_HAS_FBSCSV:-}" ]; then
-        if $OPENSSL_CMD s_client -help 2>&1 | grep fallback_scsv >/dev/null
+        if $OPENSSL s_client -help 2>&1 | grep fallback_scsv >/dev/null
         then
             OPENSSL_HAS_FBSCSV="YES"
         else
@@ -1639,8 +1650,8 @@ if [ "$MEMCHECK" -gt 0 ]; then
         exit 1
     fi
 fi
-if which $OPENSSL_CMD >/dev/null 2>&1; then :; else
-    echo "Command '$OPENSSL_CMD' not found"
+if which $OPENSSL >/dev/null 2>&1; then :; else
+    echo "Command '$OPENSSL' not found"
     exit 1
 fi
 
@@ -1695,7 +1706,7 @@ fi
 # OpenSSL 1.1.1f from Ubuntu 20.04. The syntax was only introduced in
 # OpenSSL 1.1.0 (21e0c1d23afff48601eb93135defddae51f7e2e3) and I can't find
 # a way to discover it from -help, so check the openssl version.
-case $($OPENSSL_CMD version) in
+case $($OPENSSL version) in
     "OpenSSL 0"*|"OpenSSL 1.0"*) :;;
     *)
         O_CLI="$O_CLI -cipher ALL@SECLEVEL=0"