modsign: hide openssl output in silent builds

When a user calls 'make -s', we can assume they don't want to
see any output except for warnings and errors, but instead
they see this for a warning free build:

 ###
 ### Now generating an X.509 key pair to be used for signing modules.
 ###
 ### If this takes a long time, you might wish to run rngd in the
 ### background to keep the supply of entropy topped up.  It
 ### needs to be run as root, and uses a hardware random
 ### number generator if one is available.
 ###
 Generating a 4096 bit RSA private key
 .................................................................................................................................................................................................................................++
 ..............................................................................................................................++
 writing new private key to 'certs/signing_key.pem'
 -----
 ###
 ### Key pair generated.
 ###

The output can confuse simple build testing scripts that just check
for an empty build log.

This patch silences all the output:
 - "echo" is changed to "@$(kecho)", which is dropped when "-s" gets
   passed
 - the openssl command itself is only printed with V=1, using the
   $(Q) macro
 - The output of openssl gets redirected to /dev/null on "-s" builds.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 19 insertions, 14 deletions

diff --git a/certs/Makefile b/certs/Makefile
index 28ac694dd11a..2773c4afa24c 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -36,29 +36,34 @@ ifndef CONFIG_MODULE_SIG_HASH
 $(error Could not determine digest type to use from kernel config)
 endif
 
+redirect_openssl        = 2>&1
+quiet_redirect_openssl  = 2>&1
+silent_redirect_openssl = 2>/dev/null
+
 # We do it this way rather than having a boolean option for enabling an
 # external private key, because 'make randconfig' might enable such a
 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
 $(obj)/signing_key.pem: $(obj)/x509.genkey
-        @echo "###"
-        @echo "### Now generating an X.509 key pair to be used for signing modules."
-        @echo "###"
-        @echo "### If this takes a long time, you might wish to run rngd in the"
-        @echo "### background to keep the supply of entropy topped up.  It"
-        @echo "### needs to be run as root, and uses a hardware random"
-        @echo "### number generator if one is available."
-        @echo "###"
-        openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
+        @$(kecho) "###"
+        @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
+        @$(kecho) "###"
+        @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
+        @$(kecho) "### background to keep the supply of entropy topped up.  It"
+        @$(kecho) "### needs to be run as root, and uses a hardware random"
+        @$(kecho) "### number generator if one is available."
+        @$(kecho) "###"
+        $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
                 -batch -x509 -config $(obj)/x509.genkey \
                 -outform PEM -out $(obj)/signing_key.pem \
-                -keyout $(obj)/signing_key.pem 2>&1
-        @echo "###"
-        @echo "### Key pair generated."
-        @echo "###"
+                -keyout $(obj)/signing_key.pem \
+                $($(quiet)redirect_openssl)
+        @$(kecho) "###"
+        @$(kecho) "### Key pair generated."
+        @$(kecho) "###"
 
 $(obj)/x509.genkey:
-        @echo Generating X.509 key generation config
+        @$(kecho) Generating X.509 key generation config
         @echo  >$@ "[ req ]"
         @echo >>$@ "default_bits = 4096"
         @echo >>$@ "distinguished_name = req_distinguished_name"