| # SPDX-License-Identifier: GPL-2.0 | |
| import errno | |
| import json as _json | |
| import os | |
| import random | |
| import re | |
| import select | |
| import socket | |
| import subprocess | |
| import time | |
| class CmdExitFailure(Exception): | |
| def __init__(self, msg, cmd_obj): | |
| super().__init__(msg) | |
| self.cmd = cmd_obj | |
| def fd_read_timeout(fd, timeout): | |
| rlist, _, _ = select.select([fd], [], [], timeout) | |
| if rlist: | |
| return os.read(fd, 1024) | |
| else: | |
| raise TimeoutError("Timeout waiting for fd read") | |
| class cmd: | |
| """ | |
| Execute a command on local or remote host. | |
| Use bkg() instead to run a command in the background. | |
| """ | |
| def __init__(self, comm, shell=True, fail=True, ns=None, background=False, | |
| host=None, timeout=5, ksft_wait=None): | |
| if ns: | |
| comm = f'ip netns exec {ns} ' + comm | |
| self.stdout = None | |
| self.stderr = None | |
| self.ret = None | |
| self.ksft_term_fd = None | |
| self.comm = comm | |
| if host: | |
| self.proc = host.cmd(comm) | |
| else: | |
| # ksft_wait lets us wait for the background process to fully start, | |
| # we pass an FD to the child process, and wait for it to write back. | |
| # Similarly term_fd tells child it's time to exit. | |
| pass_fds = () | |
| env = os.environ.copy() | |
| if ksft_wait is not None: | |
| rfd, ready_fd = os.pipe() | |
| wait_fd, self.ksft_term_fd = os.pipe() | |
| pass_fds = (ready_fd, wait_fd, ) | |
| env["KSFT_READY_FD"] = str(ready_fd) | |
| env["KSFT_WAIT_FD"] = str(wait_fd) | |
| self.proc = subprocess.Popen(comm, shell=shell, stdout=subprocess.PIPE, | |
| stderr=subprocess.PIPE, pass_fds=pass_fds, | |
| env=env) | |
| if ksft_wait is not None: | |
| os.close(ready_fd) | |
| os.close(wait_fd) | |
| msg = fd_read_timeout(rfd, ksft_wait) | |
| os.close(rfd) | |
| if not msg: | |
| raise Exception("Did not receive ready message") | |
| if not background: | |
| self.process(terminate=False, fail=fail, timeout=timeout) | |
| def process(self, terminate=True, fail=None, timeout=5): | |
| if fail is None: | |
| fail = not terminate | |
| if self.ksft_term_fd: | |
| os.write(self.ksft_term_fd, b"1") | |
| if terminate: | |
| self.proc.terminate() | |
| stdout, stderr = self.proc.communicate(timeout) | |
| self.stdout = stdout.decode("utf-8") | |
| self.stderr = stderr.decode("utf-8") | |
| self.proc.stdout.close() | |
| self.proc.stderr.close() | |
| self.ret = self.proc.returncode | |
| if self.proc.returncode != 0 and fail: | |
| if len(stderr) > 0 and stderr[-1] == "\n": | |
| stderr = stderr[:-1] | |
| raise CmdExitFailure("Command failed: %s\nSTDOUT: %s\nSTDERR: %s" % | |
| (self.proc.args, stdout, stderr), self) | |
| class bkg(cmd): | |
| """ | |
| Run a command in the background. | |
| Examples usage: | |
| Run a command on remote host, and wait for it to finish. | |
| This is usually paired with wait_port_listen() to make sure | |
| the command has initialized: | |
| with bkg("socat ...", exit_wait=True, host=cfg.remote) as nc: | |
| ... | |
| Run a command and expect it to let us know that it's ready | |
| by writing to a special file descriptor passed via KSFT_READY_FD. | |
| Command will be terminated when we exit the context manager: | |
| with bkg("my_binary", ksft_wait=5): | |
| """ | |
| def __init__(self, comm, shell=True, fail=None, ns=None, host=None, | |
| exit_wait=False, ksft_wait=None): | |
| super().__init__(comm, background=True, | |
| shell=shell, fail=fail, ns=ns, host=host, | |
| ksft_wait=ksft_wait) | |
| self.terminate = not exit_wait and not ksft_wait | |
| self.check_fail = fail | |
| if shell and self.terminate: | |
| print("# Warning: combining shell and terminate is risky!") | |
| print("# SIGTERM may not reach the child on zsh/ksh!") | |
| def __enter__(self): | |
| return self | |
| def __exit__(self, ex_type, ex_value, ex_tb): | |
| return self.process(terminate=self.terminate, fail=self.check_fail) | |
| global_defer_queue = [] | |
| class defer: | |
| def __init__(self, func, *args, **kwargs): | |
| global global_defer_queue | |
| if not callable(func): | |
| raise Exception("defer created with un-callable object, did you call the function instead of passing its name?") | |
| self.func = func | |
| self.args = args | |
| self.kwargs = kwargs | |
| self._queue = global_defer_queue | |
| self._queue.append(self) | |
| def __enter__(self): | |
| return self | |
| def __exit__(self, ex_type, ex_value, ex_tb): | |
| return self.exec() | |
| def exec_only(self): | |
| self.func(*self.args, **self.kwargs) | |
| def cancel(self): | |
| self._queue.remove(self) | |
| def exec(self): | |
| self.cancel() | |
| self.exec_only() | |
| def tool(name, args, json=None, ns=None, host=None): | |
| cmd_str = name + ' ' | |
| if json: | |
| cmd_str += '--json ' | |
| cmd_str += args | |
| cmd_obj = cmd(cmd_str, ns=ns, host=host) | |
| if json: | |
| return _json.loads(cmd_obj.stdout) | |
| return cmd_obj | |
| def ip(args, json=None, ns=None, host=None): | |
| if ns: | |
| args = f'-netns {ns} ' + args | |
| return tool('ip', args, json=json, host=host) | |
| def ethtool(args, json=None, ns=None, host=None): | |
| return tool('ethtool', args, json=json, ns=ns, host=host) | |
| def rand_port(type=socket.SOCK_STREAM): | |
| """ | |
| Get a random unprivileged port. | |
| """ | |
| with socket.socket(socket.AF_INET6, type) as s: | |
| s.bind(("", 0)) | |
| return s.getsockname()[1] | |
| def wait_port_listen(port, proto="tcp", ns=None, host=None, sleep=0.005, deadline=5): | |
| end = time.monotonic() + deadline | |
| pattern = f":{port:04X} .* " | |
| if proto == "tcp": # for tcp protocol additionally check the socket state | |
| pattern += "0A" | |
| pattern = re.compile(pattern) | |
| while True: | |
| data = cmd(f'cat /proc/net/{proto}*', ns=ns, host=host, shell=True).stdout | |
| for row in data.split("\n"): | |
| if pattern.search(row): | |
| return | |
| if time.monotonic() > end: | |
| raise Exception("Waiting for port listen timed out") | |
| time.sleep(sleep) |