#!/usr/bin/python3
# Validate basic syntax of shell script and yaml.

import os
import re
import stat
import subprocess
import yaml

INITRD_SERVICES_WITHOUT_BEFORE = {
    # Depended on by other services
    'coreos-livepxe-rootfs.service',
}

validated=0

def openat(dirfd, name, mode='r'):
    def opener(path, flags):
        return os.open(path, flags, dir_fd=dirfd)
    return open(name, mode, opener=opener)


def validate_initrd_service(rootfd, name):
    with openat(rootfd, name) as fh:
        if ([l for l in fh.readlines() if l.startswith('Before=')] or
                name in INITRD_SERVICES_WITHOUT_BEFORE):
            global validated
            validated += 1
        else:
            raise Exception(
                f'{name} has no Before= and may race with switch-root'
            )


BASH_UNBRACKETED_IF = re.compile(r'\sif\s+"?\$')
def validate_shell(rootfd, name):
    subprocess.check_call(['bash', '-n', name], preexec_fn=lambda: os.fchdir(rootfd))
    with openat(rootfd, name) as fh:
        if BASH_UNBRACKETED_IF.search(fh.read()):
            raise Exception(f'Possible unbracketed conditional in {name}')
    global validated
    validated +=1


for root, dirs, files, rootfd in os.fwalk('.'):
    # Skip .git
    if '.git' in dirs:
        dirs.remove('.git')
    for name in files:
        print(f"[+] Looking at {name}")
        if name.endswith(('.yaml', '.yml')):
            with open(os.open(name, dir_fd=rootfd, flags=os.O_RDONLY)) as f:
                yaml.safe_load(f)
                validated +=1
            continue
        elif name.endswith('.sh'):
            validate_shell(rootfd, name)
            continue
        elif 'dracut/modules.d' in root and name.endswith('.service'):
            validate_initrd_service(rootfd, name)
        stbuf = os.lstat(name, dir_fd=rootfd)
        if not stat.S_ISREG(stbuf.st_mode):
            continue
        if not stbuf.st_mode & stat.S_IXUSR:
            continue
        mimetype = subprocess.check_output(['file', '-b', '--mime-type', name], encoding='UTF-8',
                                        preexec_fn=lambda: os.fchdir(rootfd)).strip()
        if mimetype == 'text/x-shellscript':
            validate_shell(rootfd, name)

print(f"Validated {validated} files")