From 89efc3b4ebc11139a73a4d5c97f99ab710e29d3c Mon Sep 17 00:00:00 2001
From: Sonic <sonic.from.new.yoke@gmail.com>
Date: Thu, 10 Oct 2024 13:56:53 +0300
Subject: [PATCH] feat: add C version of CPI program (#6)

* feat: add C CPI program

* add forgotten CI step & more comments
---
 .github/workflows/main.yml     |  2 +-
 README.md                      |  1 +
 cpi/c/Makefile                 | 49 +++++++++++++++++++++++++++++++
 cpi/c/src/main.c               | 53 ++++++++++++++++++++++++++++++++++
 transfer-lamports/c/src/main.c |  2 +-
 5 files changed, 105 insertions(+), 2 deletions(-)
 create mode 100644 cpi/c/Makefile
 create mode 100644 cpi/c/src/main.c

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 7c31d04..12ac923 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -80,7 +80,7 @@ jobs:
     name: Run tests against C implementations
     strategy:
       matrix:
-        program: [helloworld, transfer-lamports]
+        program: [helloworld, transfer-lamports, cpi]
       fail-fast: false
     runs-on: ubuntu-latest
     steps:
diff --git a/README.md b/README.md
index 2be463f..82ef07a 100644
--- a/README.md
+++ b/README.md
@@ -181,3 +181,4 @@ the address and `invoke_signed` to CPI to the system program.
 | --- | --- |
 | Rust | 3662 |
 | Zig | 3141 |
+| C | 3122 |
diff --git a/cpi/c/Makefile b/cpi/c/Makefile
new file mode 100644
index 0000000..7a889b1
--- /dev/null
+++ b/cpi/c/Makefile
@@ -0,0 +1,49 @@
+LOCAL_PATH := ../../solana-c-sdk/c/
+
+.PHONY: all clean
+
+SRC_DIR ?= ./src
+OUT_DIR ?= ./out
+
+all: $(OUT_DIR)/solana_program_rosetta_cpi.so
+
+clean:
+	rm -rf $(OUT_DIR)
+
+LLVM_DIR = $(LOCAL_PATH)../dependencies/platform-tools/llvm
+LLVM_SYSTEM_INC_DIRS := $(LLVM_DIR)/lib/clang/17/include
+STD_INC_DIRS := $(LLVM_DIR)/include
+STD_LIB_DIRS := $(LLVM_DIR)/lib
+
+CC := $(LLVM_DIR)/bin/clang
+LLD := $(LLVM_DIR)/bin/ld.lld
+
+SYSTEM_INC_DIRS := \
+  $(LOCAL_PATH)inc \
+  $(LLVM_SYSTEM_INC_DIRS) \
+
+C_FLAGS := \
+  -Werror \
+  -O2 \
+  -fno-builtin \
+  -std=c17 \
+  $(addprefix -isystem,$(SYSTEM_INC_DIRS)) \
+  $(addprefix -I,$(STD_INC_DIRS)) \
+  -target sbf \
+  -fPIC
+
+SBF_LLD_FLAGS := \
+  -z notext \
+  -shared \
+  --Bdynamic \
+  $(LOCAL_PATH)sbf.ld \
+  --entry entrypoint \
+  -L $(STD_LIB_DIRS) \
+  -lc \
+
+$(OUT_DIR)/main.o: $(SRC_DIR)/main.c
+	mkdir -p $(OUT_DIR)
+	$(CC) $(C_FLAGS) -o $(OUT_DIR)/main.o -c $(SRC_DIR)/main.c
+
+$(OUT_DIR)/solana_program_rosetta_cpi.so: $(OUT_DIR)/main.o
+	$(LLD) $(SBF_LLD_FLAGS) -o $(OUT_DIR)/solana_program_rosetta_cpi.so $(OUT_DIR)/main.o
diff --git a/cpi/c/src/main.c b/cpi/c/src/main.c
new file mode 100644
index 0000000..6d3c43e
--- /dev/null
+++ b/cpi/c/src/main.c
@@ -0,0 +1,53 @@
+/**
+ * @brief C-based CPI BPF program
+ */
+#include <solana_sdk.h>
+
+/// Amount of bytes of account data to allocate
+#define SIZE 42
+
+extern uint64_t entrypoint(const uint8_t *input)
+{
+  SolAccountInfo accounts[2];
+  SolParameters params = (SolParameters){.ka = accounts};
+
+  if (!sol_deserialize(input, &params, SOL_ARRAY_SIZE(accounts)))
+  {
+    return ERROR_INVALID_ARGUMENT;
+  }
+
+  SolAccountInfo allocated_info = params.ka[0];
+  SolAccountInfo system_program_info = params.ka[1];
+
+  uint8_t seed[] = {'Y', 'o', 'u', ' ', 'p', 'a', 's', 's',
+                    ' ', 'b', 'u', 't', 't', 'e', 'r'};
+  const SolSignerSeed seeds[] = {{seed, SOL_ARRAY_SIZE(seed)},
+                                 {&params.data[0], 1}};
+
+  const SolSignerSeeds signers_seeds[] = {{seeds, SOL_ARRAY_SIZE(seeds)}};
+
+  SolPubkey expected_allocated_key;
+  if (SUCCESS != sol_create_program_address(seeds, SOL_ARRAY_SIZE(seeds),
+                                            params.program_id,
+                                            &expected_allocated_key))
+  {
+    return ERROR_INVALID_INSTRUCTION_DATA;
+  }
+
+  // allocated key does not match the derived address
+  if (!SolPubkey_same(&expected_allocated_key, allocated_info.key))
+  {
+    return ERROR_INVALID_ARGUMENT;
+  }
+
+  SolAccountMeta arguments[] = {{allocated_info.key, true, true}};
+  uint8_t data[4 + 8];            // Enough room for the Allocate instruction
+  *(uint16_t *)data = 8;          // Allocate instruction enum value
+  *(uint64_t *)(data + 4) = SIZE; // Size to allocate
+  const SolInstruction instruction = {system_program_info.key, arguments,
+                                      SOL_ARRAY_SIZE(arguments), data,
+                                      SOL_ARRAY_SIZE(data)};
+
+  return sol_invoke_signed(&instruction, params.ka, params.ka_num,
+                           signers_seeds, SOL_ARRAY_SIZE(signers_seeds));
+}
diff --git a/transfer-lamports/c/src/main.c b/transfer-lamports/c/src/main.c
index 906b5c6..0800b9c 100644
--- a/transfer-lamports/c/src/main.c
+++ b/transfer-lamports/c/src/main.c
@@ -1,5 +1,5 @@
 /**
- * @brief C-based Helloworld BPF program
+ * @brief C-based Transfer Lamports BPF program
  */
 #include <solana_sdk.h>