[Qemu-devel] [PATCH 2/2] tpm_emulator: Translate TPM error codes to strings

[Stefan Berger]

Implement a function to translate TPM error codes to strings so that
at least the most common error codes can be translated to human
readable strings.

Signed-off-by: Stefan Berger <address@hidden>
---
 hw/tpm/tpm_emulator.c | 50 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 40 insertions(+), 10 deletions(-)

diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
index 1288cbcb8d..186dde0838 100644
--- a/hw/tpm/tpm_emulator.c
+++ b/hw/tpm/tpm_emulator.c
@@ -82,6 +82,30 @@ typedef struct TPMEmulator {
     TPMBlobBuffers state_blobs;
 } TPMEmulator;
 
+struct tpm_error {
+    uint32_t tpm_result;
+    const char *string;
+};
+
+static const struct tpm_error tpm_errors[] = {
+    {  9 , "operation failed" },
+    {  32, "encryption error" },
+    {  33, "decryption error" },
+    /* TPM 2 codes */
+    { 0x101, "operation failed" },
+};
+
+static const char *tpm_emulator_strerror(uint32_t tpm_result)
+{
+    size_t i;
+
+    for (i = 0; i < ARRAY_SIZE(tpm_errors); i++) {
+        if (tpm_errors[i].tpm_result == tpm_result) {
+            return tpm_errors[i].string;
+        }
+    }
+    return "";
+}
 
 static int tpm_emulator_ctrlcmd(TPMEmulator *tpm, unsigned long cmd, void *msg,
                                 size_t msg_len_in, size_t msg_len_out)
@@ -264,7 +288,8 @@ static int tpm_emulator_stop_tpm(TPMBackend *tb)
 
     res = be32_to_cpu(res);
     if (res) {
-        error_report("tpm-emulator: TPM result for CMD_STOP: 0x%x", res);
+        error_report("tpm-emulator: TPM result for CMD_STOP: 0x%x %s", res,
+                     tpm_emulator_strerror(res));
         return -1;
     }
 
@@ -293,8 +318,9 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
 
     psbs.u.resp.tpm_result = be32_to_cpu(psbs.u.resp.tpm_result);
     if (psbs.u.resp.tpm_result != 0) {
-        error_report("tpm-emulator: TPM result for set buffer size : 0x%x",
-                     psbs.u.resp.tpm_result);
+        error_report("tpm-emulator: TPM result for set buffer size : 0x%x %s",
+                     psbs.u.resp.tpm_result,
+                     tpm_emulator_strerror(psbs.u.resp.tpm_result));
         return -1;
     }
 
@@ -339,7 +365,8 @@ static int tpm_emulator_startup_tpm_resume(TPMBackend *tb, 
size_t buffersize,
 
     res = be32_to_cpu(init.u.resp.tpm_result);
     if (res) {
-        error_report("tpm-emulator: TPM result for CMD_INIT: 0x%x", res);
+        error_report("tpm-emulator: TPM result for CMD_INIT: 0x%x %s", res,
+                     tpm_emulator_strerror(res));
         goto err_exit;
     }
     return 0;
@@ -399,8 +426,9 @@ static int 
tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
 
     res = be32_to_cpu(reset_est.u.resp.tpm_result);
     if (res) {
-        error_report("tpm-emulator: TPM result for rest establixhed flag: 
0x%x",
-                     res);
+        error_report(
+            "tpm-emulator: TPM result for rest establixhed flag: 0x%x %s",
+            res, tpm_emulator_strerror(res));
         return -1;
     }
 
@@ -638,7 +666,8 @@ static int tpm_emulator_get_state_blob(TPMEmulator *tpm_emu,
     res = be32_to_cpu(pgs.u.resp.tpm_result);
     if (res != 0 && (res & 0x800) == 0) {
         error_report("tpm-emulator: Getting the stateblob (type %d) failed "
-                     "with a TPM error 0x%x", type, res);
+                     "with a TPM error 0x%x %s", type, res,
+                     tpm_emulator_strerror(res));
         return -1;
     }
 
@@ -758,7 +787,8 @@ static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
     tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
     if (tpm_result != 0) {
         error_report("tpm-emulator: Setting the stateblob (type %d) failed "
-                     "with a TPM error 0x%x", type, tpm_result);
+                     "with a TPM error 0x%x %s", type, tpm_result,
+                     tpm_emulator_strerror(tpm_result));
         return -1;
     }
 
@@ -888,8 +918,8 @@ static void tpm_emulator_shutdown(TPMEmulator *tpm_emu)
         error_report("tpm-emulator: Could not cleanly shutdown the TPM: %s",
                      strerror(errno));
     } else if (res != 0) {
-        error_report("tpm-emulator: TPM result for sutdown: 0x%x",
-                     be32_to_cpu(res));
+        error_report("tpm-emulator: TPM result for shutdown: 0x%x %s",
+                     be32_to_cpu(res), 
tpm_emulator_strerror(be32_to_cpu(res)));
     }
 }
 
-- 
2.20.1