rust: fix vendored compilation of the git dep bip32-ed25519

Somehow, as bip32-ed25519 is a git dep, it was not actually compiled
from the local vendor folder but it was checked out into a git repo in
~/.cargo/git/ceckouts and compiled from there.

`cargo vendor` helpfully shows what needs to be added to the
config.toml so it is used.

We add the `--offline` flags to cargo build and cargo metadata to
prevent this from happening by accident in the future.

Author: benma

src/CMakeLists.txt

@@ -213,6 +213,7 @@ else()
   # For binary reproducibility, strip path prefixes that can be different depending on environment (e.g. /home/<user>, etc.).
   set(RUSTFLAGS "--remap-path-prefix=${CMAKE_CURRENT_SOURCE_DIR}/rust=src --remap-path-prefix=$ENV{HOME}=")
 endif()
+
 # Use libsecp256k1 that we link ourselves (included via external/libwally-core).
 # See https://github.com/rust-bitcoin/rust-secp256k1/tree/7c8270a8506e31731e540fab7ee1abde1f48314e/secp256k1-sys#linking-to-external-symbols
 set(RUSTFLAGS "${RUSTFLAGS} --cfg=rust_secp_no_symbol_renaming")
@@ -244,8 +245,19 @@ set(LIBBITBOX02_RUST ${LIBBITBOX02_RUST} PARENT_SCOPE)
 
 # Generate c-headers for the rust library
 add_custom_target(rust-cbindgen
+  # cbindgen can automatically create the metadata, but it does so without the `--offline` flag.
+  # The workaround is to manually create and pass the metadata.
+  COMMAND
+    ${CARGO} metadata --offline >  ${CMAKE_CURRENT_BINARY_DIR}/rust-metadata
   COMMAND
-    ${CBINDGEN} --quiet --config ${CMAKE_CURRENT_SOURCE_DIR}/rust/bitbox02-cbindgen.toml --output ${CMAKE_CURRENT_BINARY_DIR}/rust/rust.h ${LIBBITBOX02_RUST_SOURCE_DIR}
+    ${CBINDGEN}
+      --quiet
+      --config ${CMAKE_CURRENT_SOURCE_DIR}/rust/bitbox02-cbindgen.toml
+      --output ${CMAKE_CURRENT_BINARY_DIR}/rust/rust.h
+      --profile release
+      --metadata ${CMAKE_CURRENT_BINARY_DIR}/rust-metadata
+      ${LIBBITBOX02_RUST_SOURCE_DIR}
+  WORKING_DIRECTORY ${LIBBITBOX02_RUST_SOURCE_DIR}
   BYPRODUCTS
     ${CMAKE_CURRENT_BINARY_DIR}/rust/rust.h
 )
@@ -511,7 +523,7 @@ foreach(type ${RUST_LIBS})
       RUSTFLAGS=${RUSTFLAGS}
       FIRMWARE_VERSION_SHORT=${FIRMWARE_VERSION}
       $<$<BOOL:${SCCACHE_PROGRAM}>:RUSTC_WRAPPER=${SCCACHE_PROGRAM}>
-      ${CARGO} build $<$<BOOL:${CMAKE_VERBOSE_MAKEFILE}>:-v> --features target-${type} --target-dir ${RUST_BINARY_DIR}/feature-${type} ${RUST_CARGO_FLAG} ${RUST_TARGET_ARCH_ARG}
+      ${CARGO} build $<$<BOOL:${CMAKE_VERBOSE_MAKEFILE}>:-vv> --offline --features target-${type} --target-dir ${RUST_BINARY_DIR}/feature-${type} ${RUST_CARGO_FLAG} ${RUST_TARGET_ARCH_ARG}
     COMMAND
       ${CMAKE_COMMAND} -E copy_if_different ${lib} ${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/lib${type}_rust_c.a
     # DEPFILES are only supported with the Ninja build tool

src/rust/.cargo/config.toml

@@ -1,5 +1,10 @@
 [source.crates-io]
 replace-with = "vendored-sources"
 
+[source."git+https://github.com/digitalbitbox/rust-bip32-ed25519?tag=v0.1.2"]
+git = "https://github.com/digitalbitbox/rust-bip32-ed25519"
+tag = "v0.1.2"
+replace-with = "vendored-sources"
+
 [source.vendored-sources]
 directory = "vendor"

src/rust/bitbox02-rust/Cargo.toml

@@ -37,6 +37,7 @@ digest = "0.10.6"
 zeroize = "1.6.0"
 num-bigint = { version = "0.4.3", default-features = false, optional = true }
 num-traits = { version = "0.2", default-features = false, optional = true }
+# If you change this, also change src/rust/.cargo/config.toml.
 bip32-ed25519 = { git = "https://github.com/digitalbitbox/rust-bip32-ed25519", tag = "v0.1.2", optional = true }
 bech32 = { version = "0.10.0-beta", default-features = false, optional = true }
 blake2 = { version = "0.10.6", default-features = false, optional = true }