From 3668de6ae2cbeaa6771906f8d1f372ffb1e693e0 Mon Sep 17 00:00:00 2001
From: asi345 <inanata15@gmail.com>
Date: Thu, 4 Jan 2024 13:56:40 +0300
Subject: [PATCH] rust/src: add stdout print

Due to the cyclic dependency issues, rust part of the
firmware can not import std create and therefore it
does not have io capabilities, including 'println!'.
As a result, C 'printf' function is exposed to rust
as an external function.

It is a useful feature to have it because as
developers we may need to debug many parts of the
rust code when we are not using debuggers. Also,
in projects such as simulator, firmware is mainly
debugged with gdb. Hence there is limited flexibility
of debugging when execution jumps to rust. In addition,
simulator could print some of the ui elements of
firmware to stdout in this way.

Signed-off-by: asi345 <inanata15@gmail.com>
---
 src/CMakeLists.txt           | 1 +
 src/rust/bitbox02/src/lib.rs | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1adcc89496..bda608b112 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -395,6 +395,7 @@ add_custom_target(rust-bindgen
     --allowlist-function secp256k1_ecdsa_anti_exfil_host_commit
     --allowlist-function wally_get_secp_context
     --allowlist-function wally_hash160
+    --allowlist-function printf
     ${CMAKE_CURRENT_SOURCE_DIR}/rust/bitbox02-sys/wrapper.h --
     -DPB_NO_PACKED_STRUCTS=1 -DPB_FIELD_16BIT=1 -fshort-enums ${RUST_BINDGEN_FLAGS} ${RUST_INCLUDES}
   COMMAND
diff --git a/src/rust/bitbox02/src/lib.rs b/src/rust/bitbox02/src/lib.rs
index c059035494..638640bf86 100644
--- a/src/rust/bitbox02/src/lib.rs
+++ b/src/rust/bitbox02/src/lib.rs
@@ -176,6 +176,12 @@ pub fn reboot() -> ! {
     panic!("reboot called")
 }
 
+pub fn print_stdout(msg: &str) {
+    unsafe {
+        bitbox02_sys::printf(crate::util::str_to_cstr_vec(msg).unwrap().as_ptr());
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;