platform_bionic/libc/tools/genfunctosyscallnrs.py
Martijn Coenen 0c6de75a45 genfunctosyscallnrs: maps bionic functions to syscall numbers.
Bionic maps typical C functions like setresuid() to a syscall,
depending on the architecture used. This tool generates a .h
file that maps all bionic functions in SYSCALLS.txt to the
syscall number used on a particular architecture. It can then
be used to generate correct seccomp policy at runtime.

Example output in func_to_syscall_nrs.h:

Bug: 111434506
Test: manually inspect func_to_syscall_nrs.h
Change-Id: I8bc5c1cb17a2e7b5c534b2e0496411f2d419ad86
2019-01-19 09:09:30 +01:00

60 lines
2 KiB
Python
Executable file

#!/usr/bin/env python
import argparse
import collections
import logging
import os
import re
import subprocess
import textwrap
from gensyscalls import SysCallsTxtParser
from genseccomp import parse_syscall_NRs
def load_syscall_names_from_file(file_path, architecture):
parser = SysCallsTxtParser()
parser.parse_open_file(open(file_path))
arch_map = {}
for syscall in parser.syscalls:
if syscall.get(architecture):
arch_map[syscall["func"]] = syscall["name"];
return arch_map
def gen_syscall_nrs(out_file, base_syscall_file, syscall_NRs):
for arch in ('arm', 'arm64', 'mips', 'mips64', 'x86', 'x86_64'):
base_names = load_syscall_names_from_file(base_syscall_file, arch)
for func,syscall in base_names.iteritems():
out_file.write("#define __" + arch + "_" + func + " " + str(syscall_NRs[arch][syscall]) + ";\n")
def main():
parser = argparse.ArgumentParser(
description="Generates a mapping of bionic functions to system call numbers per architecture.")
parser.add_argument("--verbose", "-v", help="Enables verbose logging.")
parser.add_argument("--out-dir",
help="The output directory for the output files")
parser.add_argument("base_file", metavar="base-file", type=str,
help="The path of the base syscall list (SYSCALLS.TXT).")
parser.add_argument("files", metavar="FILE", type=str, nargs="+",
help=("A syscall name-number mapping file for an architecture.\n"))
args = parser.parse_args()
if args.verbose:
logging.basicConfig(level=logging.DEBUG)
else:
logging.basicConfig(level=logging.INFO)
syscall_files = []
syscall_NRs = {}
for filename in args.files:
m = re.search(r"libseccomp_gen_syscall_nrs_([^/]+)", filename)
syscall_NRs[m.group(1)] = parse_syscall_NRs(filename)
output_path = os.path.join(args.out_dir, "func_to_syscall_nrs.h")
with open(output_path, "w") as output_file:
gen_syscall_nrs(out_file=output_file,
syscall_NRs=syscall_NRs, base_syscall_file=args.base_file)
if __name__ == "__main__":
main()