cros: Replace "TPM" with "secure module" for machines without TPM.

chromeos/tpm/tpm_token_info_getter.cc

Index: chromeos/tpm/tpm_token_info_getter.cc
diff --git a/chromeos/tpm/tpm_token_info_getter.cc b/chromeos/tpm/tpm_token_info_getter.cc
index 1e7918d03c016ab2b6bd074ab0bb3a8126a50cd6..da88626a4d79392375cb6eaa1cdd4736bf8d9831 100644
--- a/chromeos/tpm/tpm_token_info_getter.cc
+++ b/chromeos/tpm/tpm_token_info_getter.cc
@@ -7,6 +7,8 @@
 #include <stdint.h>
 
 #include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/task_runner.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
@@ -17,6 +19,11 @@ namespace {
 const int64_t kInitialRequestDelayMs = 100;
 const int64_t kMaxRequestDelayMs = 300000;  // 5 minutes
 
+// If either of these two files exist, then we are using Cr50 and not using TPM.
+constexpr char kCr50UsedIndicatorFile1[] =
+    "/opt/google/cr50/firmware/cr50.bin.prod";
+constexpr char kCr50UsedIndicatorFile2[] = "/etc/init/cr50-update.conf";
+
 // Calculates the delay before running next attempt to initiatialize the TPM
 // token, if |last_delay| was the last or initial delay.
 base::TimeDelta GetNextRequestDelayMs(base::TimeDelta last_delay) {
@@ -61,6 +68,11 @@ std::unique_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForSystemToken(
       TYPE_SYSTEM, EmptyAccountId(), cryptohome_client, delayed_task_runner));
 }
 
+bool TPMTokenInfoGetter::IsCr50Used() {
+  return base::PathExists(base::FilePath(kCr50UsedIndicatorFile1)) ||
+         base::PathExists(base::FilePath(kCr50UsedIndicatorFile2));

[xiyuan, 2017/05/03 04:06:49]

base::PathExists touches file system and should not be called from UI thread.
Also we might want to cache the info to avoid hitting FS everytime.

[sammiequon, 2017/05/04 16:04:47]

Done. Though I am concerned with not doing this properly.

+}
+
 TPMTokenInfoGetter::~TPMTokenInfoGetter() {}
 
 void TPMTokenInfoGetter::Start(const TPMTokenInfoCallback& callback) {