Add auto-generation script for syscall mappings

Makefile

@@ -22,7 +22,7 @@ LINDFS_DIRS := \
 WITH_FPCAST ?=
 
 .PHONY: build 
-build: lindfs lind-boot sysroot
+build: generate-syscall-mappings lindfs lind-boot sysroot
 	@echo "Build complete"
 
 .PHONY: all
@@ -69,6 +69,10 @@ build_glibc:
 build-dir:
 	mkdir -p $(BUILD_DIR)
 
+.PHONY: generate-syscall-mappings
+generate-syscall-mappings: build-dir
+	python3 scripts/generate_syscall_mappings.py
+
 .PHONY: sync-sysroot
 sync-sysroot:
 	$(RM) -r $(SYSROOT_DIR)

docs/contribute/toolchain.md

@@ -35,7 +35,19 @@ options.
     Matching builtins are available in the *lind-wasm* repo under
     [`src/glibc/wasi`](https://github.com/Lind-Project/lind-wasm/tree/main/src/glibc/wasi).
 
-3. __Build *glibc* and generate sysroot__ (see [`make sysroot`](https://github.com/Lind-Project/lind-wasm/blob/main/Makefile))
+3. __Generate syscall mappings__ (see [`make generate-syscall-mappings`](https://github.com/Lind-Project/lind-wasm/blob/main/Makefile))
+
+    Auto-generates syscall mapping constants from `src/glibc/lind_syscall/lind_syscall_num.h` 
+    and produces `src/sysdefs/src/constants/syscall_const.rs`. This must run before building *glibc* 
+    and *wasmtime* to ensure Rust code has the correct syscall definitions.
+
+    ```bash
+    python3 scripts/generate_syscall_mappings.py
+    ```
+
+    The source of truth is the Linux x86_64 syscall table as defined in the *glibc* header file.
+
+4. __Build *glibc* and generate sysroot__ (see [`make sysroot`](https://github.com/Lind-Project/lind-wasm/blob/main/Makefile))
     1. Configure and compile *glibc* for the *WASI* target with *Clang*
 
     2. Compile extra files:
@@ -51,7 +63,7 @@ options.
         along with headers and a pre-built C runtime into a
         sysroot directory structure as required by *Clang*.
 
-4. __Build custom wasmtime__ (see [`make wasmtime`](https://github.com/Lind-Project/lind-wasm/blob/main/Makefile))
+5. __Build custom wasmtime__ (see [`make wasmtime`](https://github.com/Lind-Project/lind-wasm/blob/main/Makefile))
 
       Builds `src/wasmtime` workspace. Custom dependencies `fdtables`, `RawPOSIX`
       and `sysdefs` are included in the build automatically.

scripts/generate_syscall_mappings.py

@@ -0,0 +1,98 @@
+#!/usr/bin/env python3
+# Auto-generates syscall mapping constants for lind-wasm.
+#
+# Reads syscall definitions from glibc's lind_syscall_num.h and generates:
+#  - src/sysdefs/src/constants/syscall_const.rs (full set of syscalls)
+#
+# This script should be run before building lind-boot and glibc.
+#
+# Source of truth: src/glibc/lind_syscall/lind_syscall_num.h
+
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+
+def parse_c_header(header_path: str) -> dict[str, int]:
+    """Parse syscall constants from glibc's lind_syscall_num.h header file."""
+    syscalls = {}
+
+    try:
+        with open(header_path) as f:
+            content = f.read()
+    except FileNotFoundError:
+        print(f"Error: Could not find {header_path}", file=sys.stderr)
+        sys.exit(1)
+
+    # Match #define SYSCALL_NAME number
+    pattern = r'#define\s+(\w+)\s+(\d+)'
+
+    for match in re.finditer(pattern, content):
+        name, number = match.groups()
+        syscalls[name] = int(number)
+
+    if not syscalls:
+        print(f"Error: Could not parse any syscalls from {header_path}", file=sys.stderr)
+        sys.exit(1)
+
+    return syscalls
+
+
+def generate_rust_constants(syscalls: dict[str, int]) -> str:
+    """Generate Rust constants for sysdefs/constants/syscall_const.rs."""
+    lines = [
+        "//! Syscall number constants for the Lind platform.",
+        "//!",
+        "//! Source of truth: Linux x86_64 syscall table",
+        "//!   https://github.com/torvalds/linux/blob/v6.16-rc1/arch/x86/entry/syscalls/syscall_64.tbl",
+        "//! (Historical overview: https://filippo.io/linux-syscall-table/)",
+        "//!",
+        "//! Keep these in sync with glibc's lind_syscall_num.h and RawPOSIX dispatcher.",
+        "",
+    ]
+
+    # Sort by syscall number for readability
+    sorted_syscalls = sorted(syscalls.items(), key=lambda x: x[1])
+
+    for name, number in sorted_syscalls:
+        lines.append(f"pub const {name}: i32 = {number};")
+
+    lines.append("")
+    return "\n".join(lines)
+
+
+
+
+
+def write_file(path: str, content: str) -> None:
+    """Write content to file, creating directories if needed."""
+    Path(path).parent.mkdir(parents=True, exist_ok=True)
+    with open(path, 'w') as f:
+        f.write(content)
+    print(f"Generated: {path}")
+
+
+def main() -> None:
+    """Generate syscall mapping constants from glibc header."""
+    # Find workspace root (should be run from lind-wasm directory)
+    workspace_root = Path(__file__).parent.parent
+
+    c_header = workspace_root / "src/glibc/lind_syscall/lind_syscall_num.h"
+    rust_sysdefs_out = workspace_root / "src/sysdefs/src/constants/syscall_const.rs"
+
+    print("Parsing syscall definitions...")
+    syscalls = parse_c_header(str(c_header))
+    print(f"Found {len(syscalls)} syscall definitions")
+
+    # Generate Rust constants for sysdefs
+    print("\nGenerating sysdefs constants...")
+    rust_content = generate_rust_constants(syscalls)
+    write_file(str(rust_sysdefs_out), rust_content)
+
+    print("Done!")
+
+
+if __name__ == "__main__":
+    main()