Add support for idiomatic error handling to BPF instruction processors (#7968)

programs/bpf/c/src/error_handling/error_handling.c

@@ -0,0 +1,37 @@
+/**
+ * @brief Example C-based BPF program that exercises duplicate keyed ka
+ * passed to it
+ */
+#include <solana_sdk.h>
+
+/**
+ * Custom error for when input serialization fails
+ */
+
+extern uint32_t entrypoint(const uint8_t *input) {
+  SolKeyedAccount ka[4];
+  SolParameters params = (SolParameters) { .ka = ka };
+
+  if (!sol_deserialize(input, &params, SOL_ARRAY_SIZE(ka))) {
+    return INVALID_ARGUMENT;
+  }
+
+  switch (params.data[0]) {
+    case(1):
+        sol_log("return success");
+        return SUCCESS;
+    case(2):
+        sol_log("return a builtin");
+        return INVALID_ACCOUNT_DATA;
+    case(3):
+        sol_log("return custom error");
+        return 42;
+    case(4):
+        sol_log("return error that conflicts with success");
+        return 0x40000000;
+    default:
+        sol_log("Unrecognized command");
+        return INVALID_INSTRUCTION_DATA;
+  }
+  return SUCCESS;
+}