From 053431bb3a4c6f81ab88f13f39d2a093180d7e3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Fri, 5 Aug 2022 21:25:24 +0200
Subject: [PATCH] tpm: Make tss2 log into /dev/null

There is no way yet[1] to control how much tss2 logs and to where, from the C
API. The problem with that is if there is no TPM 2.0 module, it'll very
verbosely tell about it via ERROR and WARNING log entries directly to
stderr, which isn't really what we want.

Change this by setting the env var controlling the log target to
/dev/null unless the tpm debug key is enabled.

[1] https://github.com/tpm2-software/tpm2-tss/pull/2087
---
 src/grd-debug.c   | 1 +
 src/grd-debug.h   | 1 +
 src/grd-tpm.c     | 5 +++++
 src/meson.build   | 2 ++
 tests/meson.build | 2 ++
 5 files changed, 11 insertions(+)

diff --git a/src/grd-debug.c b/src/grd-debug.c
index c556f10d..3e0c6675 100644
--- a/src/grd-debug.c
+++ b/src/grd-debug.c
@@ -26,6 +26,7 @@
 
 static const GDebugKey grd_debug_keys[] = {
   { "vnc", GRD_DEBUG_VNC },
+  { "tpm", GRD_DEBUG_TPM },
 };
 
 static GrdDebugFlags debug_flags;
diff --git a/src/grd-debug.h b/src/grd-debug.h
index a88fdfe7..47ac28fb 100644
--- a/src/grd-debug.h
+++ b/src/grd-debug.h
@@ -25,6 +25,7 @@ typedef enum _GrdDebugFlags
 {
   GRD_DEBUG_NONE = 0,
   GRD_DEBUG_VNC = 1 << 0,
+  GRD_DEBUG_TPM = 1 << 1,
 } GrdDebugFlags;
 
 GrdDebugFlags grd_get_debug_flags (void);
diff --git a/src/grd-tpm.c b/src/grd-tpm.c
index 06624f88..ff88c607 100644
--- a/src/grd-tpm.c
+++ b/src/grd-tpm.c
@@ -32,6 +32,8 @@ G_GNUC_BEGIN_IGNORE_DEPRECATIONS
 #include <tss2_tctildr.h>
 G_GNUC_END_IGNORE_DEPRECATIONS
 
+#include "grd-debug.h"
+
 struct _GrdTpm
 {
   GObject parent;
@@ -722,6 +724,9 @@ grd_tpm_new (GrdTpmMode   mode,
 
   tpm = g_object_new (GRD_TYPE_TPM, NULL);
 
+  if (!(grd_get_debug_flags () & GRD_DEBUG_TPM))
+    g_setenv ("TSS2_LOGFILE", "/dev/null", TRUE);
+
   if (!init_transmission_interface (tpm, error))
     return NULL;
 
diff --git a/src/meson.build b/src/meson.build
index b5be2c34..6506d92f 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -176,6 +176,8 @@ control_sources = ([
 
 ctl_sources = ([
   'grd-ctl.c',
+  'grd-debug.c',
+  'grd-debug.h',
   credentials_sources,
 ])
 
diff --git a/tests/meson.build b/tests/meson.build
index 31247291..3dd360d2 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -72,6 +72,8 @@ tpm_test = executable(
   'tpm-test',
   sources: [
     'tpm-test.c',
+    '../src/grd-debug.c',
+    '../src/grd-debug.h',
     '../src/grd-tpm.c',
     '../src/grd-tpm.h',
   ],