debug output

Author: real-or-random

examples/examples_util.h

@@ -106,3 +106,23 @@ static void secure_erase(void *ptr, size_t len) {
     volatile_memset(ptr, 0, len);
 #endif
 }
+
+/* Debug helper for printing arrays of unsigned char. */
+#define PRINT_BUF(buf, len) do { \
+    printf("%s[%lu] = ", #buf, (unsigned long)len); \
+    print_buf_plain(buf, len); \
+} while(0)
+
+static void print_buf_plain(const unsigned char *buf, size_t len) {
+    size_t i;
+    printf("{");
+    for (i = 0; i < len; i++) {
+        if (i % 8 == 0) {
+            printf("\n    ");
+        } else {
+            printf(" ");
+        }
+        printf("0x%02X,", buf[i]);
+    }
+    printf("\n}\n");
+}

examples/silentpayments.c

@@ -101,6 +101,12 @@ const unsigned char* label_lookup(
     const struct labels_cache* cache = (const struct labels_cache*)cache_ptr;
     size_t i;
     for (i = 0; i < cache->entries_used; i++) {
+        printf("i = %ld\n", i);
+        printf("cache->entries[i].label = \n");
+        PRINT_BUF(cache->entries[i].label, 33);
+        printf("label = 33\n");
+        PRINT_BUF(label33, 33);
+        printf("\n\n");
         if (memcmp(cache->entries[i].label, label33, 33) == 0) {
             return cache->entries[i].label_tweak;
         }

src/modules/silentpayments/main_impl.h

@@ -571,7 +571,7 @@ int secp256k1_silentpayments_recipient_scan_outputs(
                  * label1 = tx_output - P_output */
                 secp256k1_gej_add_ge_var(&label_gej, &tx_output_gej, &P_output_negated_ge, NULL);
                 secp256k1_ge_set_gej(&label_ge, &label_gej);
-                secp256k1_eckey_pubkey_serialize(&label_ge, label33, &len, 1);
+                if (!secp256k1_eckey_pubkey_serialize(&label_ge, label33, &len, 1)) { exit(1) }
                 label_tweak = label_lookup(label33, label_context);
                 if (label_tweak != NULL) {
                     found = 1;
@@ -584,7 +584,7 @@ int secp256k1_silentpayments_recipient_scan_outputs(
                  * label2 = -tx_output - P_output */
                 secp256k1_gej_add_ge_var(&label_gej, &label_gej, &P_output_negated_ge, NULL);
                 secp256k1_ge_set_gej(&label_ge, &label_gej);
-                secp256k1_eckey_pubkey_serialize(&label_ge, label33, &len, 1);
+                if (!secp256k1_eckey_pubkey_serialize(&label_ge, label33, &len, 1)) { exit(1) }
                 label_tweak = label_lookup(label33, label_context);
                 if (label_tweak != NULL) {
                     found = 1;