scripts: Introduce syscall.py

`syscall.py` contains functions used to extract `syscall_table` from
headers installed by `kernel_source.py` and generate according Rust code
for specific architecture.

Signed-off-by: Ruoqing He <[email protected]>

Author: RuoqingHe

scripts/lib/syscall.py

@@ -0,0 +1,55 @@
+# Copyright 2025 © Institute of Software, CAS. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+import subprocess
+import re
+
+
+def generate_syscall_table(file_path):
+    """Generate syscall table from specified header file"""
+    try:
+        with open(file_path, "r") as f:
+            syscalls = []
+            pattern = re.compile(r"^#define __NR_(\w+)\s+(\d+)")
+
+            for line in f:
+                line = line.strip()
+                if line.startswith("#define __NR_"):
+                    match = pattern.match(line)
+                    if match:
+                        name = match.group(1)
+                        num = int(match.group(2))
+                        syscalls.append((name, num))
+
+            # Sort alphabetically by syscall name
+            syscalls.sort(key=lambda x: x[0])
+            syscall_list = [f'("{name}", {num}),' for name, num in syscalls]
+            return " ".join(syscall_list)
+
+    except FileNotFoundError:
+        raise RuntimeError(f"Header file not found: {file_path}")
+    except Exception as e:
+        raise RuntimeError(f"File processing failed: {str(e)}")
+
+
+def generate_rust_code(syscalls, output_path):
+    """Generate Rust code and format with rustfmt"""
+    print(f"Generating to: {output_path}")
+    code = f"""use std::collections::HashMap;
+pub(crate) fn make_syscall_table() -> HashMap<&'static str, i64> {{
+    vec![
+        {syscalls}
+    ].into_iter().collect()
+}}
+"""
+    try:
+        with open(output_path, "w") as f:
+            f.write(code)
+
+        # Format with rustfmt
+        subprocess.run(["rustfmt", output_path], check=True)
+        print(f"Generation succeeded: {output_path}")
+    except subprocess.CalledProcessError:
+        raise RuntimeError("rustfmt formatting failed")
+    except IOError as e:
+        raise RuntimeError(f"File write error: {str(e)}")