Source code for xonsh.procs.specs

"""Subprocess specification and related utilities."""
import contextlib
import inspect
import io
import os
import pathlib
import re
import shlex
import signal
import stat
import subprocess
import sys

import xonsh.environ as xenv
import xonsh.jobs as xj
import xonsh.lazyasd as xl
import xonsh.lazyimps as xli
import xonsh.platform as xp
import xonsh.tools as xt
from xonsh.built_ins import XSH
from xonsh.procs.pipelines import (
    STDOUT_CAPTURE_KINDS,
    CommandPipeline,
    HiddenCommandPipeline,
    resume_process,
)
from xonsh.procs.posix import PopenThread
from xonsh.procs.proxies import ProcProxy, ProcProxyThread
from xonsh.procs.readers import ConsoleParallelReader


@xl.lazyobject
def RE_SHEBANG():
    return re.compile(r"#![ \t]*(.+?)$")


[docs]def is_app_execution_alias(fname): """App execution aliases behave strangly on Windows and Python. Here we try to detect if a file is an app execution alias. """ fname = pathlib.Path(fname) try: return fname.stat().st_reparse_tag == stat.IO_REPARSE_TAG_APPEXECLINK # os.stat().st_reparse_tag is python 3.8+, and os.stat(app_exec_alias) throws OSError for <= 3.7 # so use old method as fallback except (AttributeError, OSError): return not os.path.exists(fname) and fname.name in os.listdir(fname.parent)
def _is_binary(fname, limit=80): try: with open(fname, "rb") as f: for _ in range(limit): char = f.read(1) if char == b"\0": return True if char == b"\n": return False if char == b"": return except OSError as e: if xp.ON_WINDOWS and is_app_execution_alias(fname): return True raise e return False def _un_shebang(x): if x == "/usr/bin/env": return [] elif any(x.startswith(i) for i in ["/usr/bin", "/usr/local/bin", "/bin"]): x = os.path.basename(x) elif x.endswith("python") or x.endswith("python.exe"): x = "python" if x == "xonsh": return ["python", "-m", "xonsh.main"] return [x]
[docs]def get_script_subproc_command(fname, args): """Given the name of a script outside the path, returns a list representing an appropriate subprocess command to execute the script or None if the argument is not readable or not a script. Raises PermissionError if the script is not executable. """ # make sure file is executable if not os.access(fname, os.X_OK): if not xp.ON_CYGWIN: raise PermissionError # explicitly look at all PATH entries for cmd w_path = os.getenv("PATH").split(":") w_fpath = list(map(lambda p: p + os.sep + fname, w_path)) if not any(list(map(lambda c: os.access(c, os.X_OK), w_fpath))): raise PermissionError if xp.ON_POSIX and not os.access(fname, os.R_OK): # on some systems, some important programs (e.g. sudo) will have # execute permissions but not read/write permissions. This enables # things with the SUID set to be run. Needs to come before _is_binary() # is called, because that function tries to read the file. return None elif _is_binary(fname): # if the file is a binary, we should call it directly return None if xp.ON_WINDOWS: # Windows can execute various filetypes directly # as given in PATHEXT _, ext = os.path.splitext(fname) if ext.upper() in XSH.env.get("PATHEXT"): return [fname] + args # find interpreter with open(fname, "rb") as f: first_line = f.readline().decode().strip() m = RE_SHEBANG.match(first_line) # xonsh is the default interpreter if m is None: interp = ["xonsh"] else: interp = m.group(1).strip() if len(interp) > 0: interp = shlex.split(interp) else: interp = ["xonsh"] if xp.ON_WINDOWS: o = [] for i in interp: o.extend(_un_shebang(i)) interp = o return interp + [fname] + args
@xl.lazyobject def _REDIR_REGEX(): name = r"(o(?:ut)?|e(?:rr)?|a(?:ll)?|&?\d?)" return re.compile("{r}(>?>|<){r}$".format(r=name)) @xl.lazyobject def _MODES(): return {">>": "a", ">": "w", "<": "r"} @xl.lazyobject def _WRITE_MODES(): return frozenset({"w", "a"}) @xl.lazyobject def _REDIR_ALL(): return frozenset({"&", "a", "all"}) @xl.lazyobject def _REDIR_ERR(): return frozenset({"2", "e", "err"}) @xl.lazyobject def _REDIR_OUT(): return frozenset({"", "1", "o", "out"}) @xl.lazyobject def _E2O_MAP(): return frozenset({f"{e}>{o}" for e in _REDIR_ERR for o in _REDIR_OUT if o != ""}) @xl.lazyobject def _O2E_MAP(): return frozenset({f"{o}>{e}" for e in _REDIR_ERR for o in _REDIR_OUT if o != ""}) def _is_redirect(x): return isinstance(x, str) and _REDIR_REGEX.match(x)
[docs]def safe_open(fname, mode, buffering=-1): """Safely attempts to open a file in for xonsh subprocs.""" # file descriptors try: return open(fname, mode, buffering=buffering) except PermissionError: raise xt.XonshError(f"xonsh: {fname}: permission denied") except FileNotFoundError: raise xt.XonshError(f"xonsh: {fname}: no such file or directory") except Exception: raise xt.XonshError(f"xonsh: {fname}: unable to open file")
[docs]def safe_close(x): """Safely attempts to close an object.""" if not isinstance(x, io.IOBase): return if x.closed: return try: x.close() except Exception: pass
def _parse_redirects(r, loc=None): """returns origin, mode, destination tuple""" orig, mode, dest = _REDIR_REGEX.match(r).groups() # redirect to fd if dest.startswith("&"): try: dest = int(dest[1:]) if loc is None: loc, dest = dest, "" # NOQA else: e = f"Unrecognized redirection command: {r}" raise xt.XonshError(e) except (ValueError, xt.XonshError): raise except Exception: pass mode = _MODES.get(mode, None) if mode == "r" and (len(orig) > 0 or len(dest) > 0): raise xt.XonshError(f"Unrecognized redirection command: {r}") elif mode in _WRITE_MODES and len(dest) > 0: raise xt.XonshError(f"Unrecognized redirection command: {r}") return orig, mode, dest def _redirect_streams(r, loc=None): """Returns stdin, stdout, stderr tuple of redirections.""" stdin = stdout = stderr = None no_ampersand = r.replace("&", "") # special case of redirecting stderr to stdout if no_ampersand in _E2O_MAP: stderr = subprocess.STDOUT return stdin, stdout, stderr elif no_ampersand in _O2E_MAP: stdout = 2 # using 2 as a flag, rather than using a file object return stdin, stdout, stderr # get streams orig, mode, dest = _parse_redirects(r) if mode == "r": stdin = safe_open(loc, mode) elif mode in _WRITE_MODES: if orig in _REDIR_ALL: stdout = stderr = safe_open(loc, mode) elif orig in _REDIR_OUT: stdout = safe_open(loc, mode) elif orig in _REDIR_ERR: stderr = safe_open(loc, mode) else: raise xt.XonshError(f"Unrecognized redirection command: {r}") else: raise xt.XonshError(f"Unrecognized redirection command: {r}") return stdin, stdout, stderr
[docs]def default_signal_pauser(n, f): """Pauses a signal, as needed.""" signal.pause()
[docs]def no_pg_xonsh_preexec_fn(): """Default subprocess preexec function for when there is no existing pipeline group. """ os.setpgrp() signal.signal(signal.SIGTSTP, default_signal_pauser)
[docs]class SubprocSpec: """A container for specifying how a subprocess command should be executed. """ kwnames = ("stdin", "stdout", "stderr", "universal_newlines", "close_fds") def __init__( self, cmd, cls=subprocess.Popen, stdin=None, stdout=None, stderr=None, universal_newlines=False, close_fds=False, captured=False, env=None, ): """ Parameters ---------- cmd : list of str Command to be run. cls : Popen-like Class to run the subprocess with. stdin : file-like Popen file descriptor or flag for stdin. stdout : file-like Popen file descriptor or flag for stdout. stderr : file-like Popen file descriptor or flag for stderr. universal_newlines : bool Whether or not to use universal newlines. close_fds : bool Whether or not to close the file descriptors when the process exits. captured : bool or str, optional The flag for if the subprocess is captured, may be one of: False for $[], 'stdout' for $(), 'hiddenobject' for ![], or 'object' for !(). env : dict Replacement environment to run the subporcess in. Attributes ---------- args : list of str Arguments as originally supplied. alias : list of str, callable, or None The alias that was resolved for this command, if any. binary_loc : str or None Path to binary to execute. is_proxy : bool Whether or not the subprocess is or should be run as a proxy. background : bool Whether or not the subprocess should be started in the background. threadable : bool Whether or not the subprocess is able to be run in a background thread, rather than the main thread. pipeline_index : int or None The index number of this sepc into the pipeline that is being setup. last_in_pipeline : bool Whether the subprocess is the last in the execution pipeline. captured_stdout : file-like Handle to captured stdin captured_stderr : file-like Handle to captured stderr stack : list of FrameInfo namedtuples or None The stack of the call-site of alias, if the alias requires it. None otherwise. """ self._stdin = self._stdout = self._stderr = None # args self.cmd = list(cmd) self.cls = cls self.stdin = stdin self.stdout = stdout self.stderr = stderr self.universal_newlines = universal_newlines self.close_fds = close_fds self.captured = captured if env is not None: self.env = { k: v if not (isinstance(v, list)) or len(v) > 1 else v[0] for (k, v) in env.items() } else: self.env = None # pure attrs self.args = list(cmd) self.alias = None self.alias_name = None self.alias_stack = XSH.env.get("__ALIAS_STACK", "").split(":") self.binary_loc = None self.is_proxy = False self.background = False self.threadable = True self.pipeline_index = None self.last_in_pipeline = False self.captured_stdout = None self.captured_stderr = None self.stack = None def __str__(self): s = self.__class__.__name__ + "(" + str(self.cmd) + ", " s += self.cls.__name__ + ", " kws = [n + "=" + str(getattr(self, n)) for n in self.kwnames] s += ", ".join(kws) + ")" return s def __repr__(self): s = self.__class__.__name__ + "(" + repr(self.cmd) + ", " s += self.cls.__name__ + ", " kws = [n + "=" + repr(getattr(self, n)) for n in self.kwnames] s += ", ".join(kws) + ")" return s # # Properties # @property def stdin(self): return self._stdin @stdin.setter def stdin(self, value): if self._stdin is None: self._stdin = value elif value is None: pass else: safe_close(value) msg = "Multiple inputs for stdin for {0!r}" msg = msg.format(" ".join(self.args)) raise xt.XonshError(msg) @property def stdout(self): return self._stdout @stdout.setter def stdout(self, value): if self._stdout is None: self._stdout = value elif value is None: pass else: safe_close(value) msg = "Multiple redirections for stdout for {0!r}" msg = msg.format(" ".join(self.args)) raise xt.XonshError(msg) @property def stderr(self): return self._stderr @stderr.setter def stderr(self, value): if self._stderr is None: self._stderr = value elif value is None: pass else: safe_close(value) msg = "Multiple redirections for stderr for {0!r}" msg = msg.format(" ".join(self.args)) raise xt.XonshError(msg) # # Execution methods #
[docs] def run(self, *, pipeline_group=None): """Launches the subprocess and returns the object.""" event_name = self._cmd_event_name() self._pre_run_event_fire(event_name) kwargs = {n: getattr(self, n) for n in self.kwnames} if callable(self.alias): kwargs["env"] = self.env or {} kwargs["env"]["__ALIAS_NAME"] = self.alias_name or "" p = self.cls(self.alias, self.cmd, **kwargs) else: self.prep_env_subproc(kwargs) self.prep_preexec_fn(kwargs, pipeline_group=pipeline_group) self._fix_null_cmd_bytes() p = self._run_binary(kwargs) p.spec = self p.last_in_pipeline = self.last_in_pipeline p.captured_stdout = self.captured_stdout p.captured_stderr = self.captured_stderr self._post_run_event_fire(event_name, p) return p
def _run_binary(self, kwargs): if not self.cmd[0]: raise xt.XonshError("xonsh: subprocess mode: command is empty") bufsize = 1 try: if xp.ON_WINDOWS and self.binary_loc is not None: # launch process using full paths (https://bugs.python.org/issue8557) cmd = [self.binary_loc] + self.cmd[1:] else: cmd = self.cmd p = self.cls(cmd, bufsize=bufsize, **kwargs) except PermissionError: e = "xonsh: subprocess mode: permission denied: {0}" raise xt.XonshError(e.format(self.cmd[0])) except FileNotFoundError: cmd0 = self.cmd[0] if len(self.cmd) == 1 and cmd0.endswith("?"): with contextlib.suppress(OSError): return self.cls( ["man", cmd0.rstrip("?")], bufsize=bufsize, **kwargs ) e = f"xonsh: subprocess mode: command not found: {cmd0}" env = XSH.env sug = xt.suggest_commands(cmd0, env) if len(sug.strip()) > 0: e += "\n" + xt.suggest_commands(cmd0, env) if XSH.env.get("XONSH_INTERACTIVE"): events = XSH.builtins.events events.on_command_not_found.fire(cmd=self.cmd) raise xt.XonshError(e) return p
[docs] def prep_env_subproc(self, kwargs): """Prepares the environment to use in the subprocess.""" with XSH.env.swap(self.env) as env: denv = env.detype() if xp.ON_WINDOWS: # Over write prompt variable as xonsh's $PROMPT does # not make much sense for other subprocs denv["PROMPT"] = "$P$G" kwargs["env"] = denv
[docs] def prep_preexec_fn(self, kwargs, pipeline_group=None): """Prepares the 'preexec_fn' keyword argument""" if not xp.ON_POSIX: return if not XSH.env.get("XONSH_INTERACTIVE"): return if pipeline_group is None or xp.ON_WSL1: # If there is no pipeline group # or the platform is windows subsystem for linux (WSL) xonsh_preexec_fn = no_pg_xonsh_preexec_fn else: def xonsh_preexec_fn(): """Preexec function bound to a pipeline group.""" os.setpgid(0, pipeline_group) signal.signal( signal.SIGTERM if xp.ON_WINDOWS else signal.SIGTSTP, default_signal_pauser, ) kwargs["preexec_fn"] = xonsh_preexec_fn
def _fix_null_cmd_bytes(self): # Popen does not accept null bytes in its input commands. # That doesn't stop some subprocesses from using them. Here we # escape them just in case. cmd = self.cmd for i in range(len(cmd)): if callable(cmd[i]): raise Exception(f"The command contains callable argument: {cmd[i]}") cmd[i] = cmd[i].replace("\0", "\\0") def _cmd_event_name(self): if callable(self.alias): return getattr(self.alias, "__name__", repr(self.alias)) elif self.binary_loc is None: return "<not-found>" else: return os.path.basename(self.binary_loc) def _pre_run_event_fire(self, name): events = XSH.builtins.events event_name = "on_pre_spec_run_" + name if events.exists(event_name): event = getattr(events, event_name) event.fire(spec=self) def _post_run_event_fire(self, name, proc): events = XSH.builtins.events event_name = "on_post_spec_run_" + name if events.exists(event_name): event = getattr(events, event_name) event.fire(spec=self, proc=proc) # # Building methods #
[docs] @classmethod def build(kls, cmd, *, cls=subprocess.Popen, **kwargs): """Creates an instance of the subprocess command, with any modifications and adjustments based on the actual cmd that was received. """ if not cmd: raise xt.XonshError("xonsh: subprocess mode: command is empty") # modifications that do not alter cmds may come before creating instance spec = kls(cmd, cls=cls, **kwargs) # modifications that alter cmds must come after creating instance # perform initial redirects spec.redirect_leading() spec.redirect_trailing() # apply aliases spec.resolve_alias() spec.resolve_binary_loc() spec.resolve_auto_cd() spec.resolve_executable_commands() spec.resolve_alias_cls() spec.resolve_stack() return spec
[docs] def redirect_leading(self): """Manage leading redirects such as with '< input.txt COMMAND'.""" while len(self.cmd) >= 3 and self.cmd[0] == "<": self.stdin = safe_open(self.cmd[1], "r") self.cmd = self.cmd[2:]
[docs] def redirect_trailing(self): """Manages trailing redirects.""" while True: cmd = self.cmd if len(cmd) >= 3 and _is_redirect(cmd[-2]): streams = _redirect_streams(cmd[-2], cmd[-1]) self.stdin, self.stdout, self.stderr = streams self.cmd = cmd[:-2] elif len(cmd) >= 2 and _is_redirect(cmd[-1]): streams = _redirect_streams(cmd[-1]) self.stdin, self.stdout, self.stderr = streams self.cmd = cmd[:-1] else: break
[docs] def resolve_alias(self): """Sets alias in command, if applicable.""" cmd0 = self.cmd[0] if cmd0 in self.alias_stack: # Disabling the alias resolving to prevent infinite loop in call stack # and futher using binary_loc to resolve the alias name. self.alias = None return if callable(cmd0): alias = cmd0 else: alias = XSH.aliases.get(cmd0, None) if alias is not None: self.alias_name = cmd0 self.alias = alias
[docs] def resolve_binary_loc(self): """Sets the binary location""" alias = self.alias if alias is None: cmd0 = self.cmd[0] binary_loc = xenv.locate_binary(cmd0) if binary_loc == cmd0 and cmd0 in self.alias_stack: raise Exception(f'Recursive calls to "{cmd0}" alias.') elif callable(alias): binary_loc = None else: binary_loc = xenv.locate_binary(alias[0]) self.binary_loc = binary_loc
[docs] def resolve_auto_cd(self): """Implements AUTO_CD functionality.""" if not ( self.alias is None and self.binary_loc is None and len(self.cmd) == 1 and XSH.env.get("AUTO_CD") and os.path.isdir(self.cmd[0]) ): return self.cmd.insert(0, "cd") self.alias = XSH.aliases.get("cd", None)
[docs] def resolve_executable_commands(self): """Resolve command executables, if applicable.""" alias = self.alias if alias is None: pass elif callable(alias): self.cmd.pop(0) return else: self.cmd = alias + self.cmd[1:] # resolve any redirects the aliases may have applied self.redirect_leading() self.redirect_trailing() if self.binary_loc is None: return try: scriptcmd = get_script_subproc_command(self.binary_loc, self.cmd[1:]) if scriptcmd is not None: self.cmd = scriptcmd except PermissionError: e = "xonsh: subprocess mode: permission denied: {0}" raise xt.XonshError(e.format(self.cmd[0]))
[docs] def resolve_alias_cls(self): """Determine which proxy class to run an alias with.""" alias = self.alias if not callable(alias): return self.is_proxy = True env = XSH.env thable = env.get("THREAD_SUBPROCS") and getattr( alias, "__xonsh_threadable__", True ) cls = ProcProxyThread if thable else ProcProxy self.cls = cls self.threadable = thable # also check capturability, while we are here cpable = getattr(alias, "__xonsh_capturable__", self.captured) self.captured = cpable
[docs] def resolve_stack(self): """Computes the stack for a callable alias's call-site, if needed.""" if not callable(self.alias): return # check that we actual need the stack sig = inspect.signature(self.alias) if len(sig.parameters) <= 5 and "stack" not in sig.parameters: return # compute the stack, and filter out these build methods # run_subproc() is the 4th command in the stack # we want to filter out one up, e.g. subproc_captured_hiddenobject() # after that the stack from the call site starts. stack = inspect.stack(context=0) assert stack[3][3] == "run_subproc", "xonsh stack has changed!" del stack[:5] self.stack = stack
def _safe_pipe_properties(fd, use_tty=False): """Makes sure that a pipe file descriptor properties are reasonable.""" if not use_tty: return # due to some weird, long standing issue in Python, PTYs come out # replacing newline \n with \r\n. This causes issues for raw unix # protocols, like git and ssh, which expect unix line endings. # see https://mail.python.org/pipermail/python-list/2013-June/650460.html # for more details and the following solution. props = xli.termios.tcgetattr(fd) props[1] = props[1] & (~xli.termios.ONLCR) | xli.termios.ONLRET xli.termios.tcsetattr(fd, xli.termios.TCSANOW, props) # newly created PTYs have a stardard size (24x80), set size to the same size # than the current terminal winsize = None if sys.stdin.isatty(): winsize = xli.fcntl.ioctl(sys.stdin.fileno(), xli.termios.TIOCGWINSZ, b"0000") elif sys.stdout.isatty(): winsize = xli.fcntl.ioctl(sys.stdout.fileno(), xli.termios.TIOCGWINSZ, b"0000") elif sys.stderr.isatty(): winsize = xli.fcntl.ioctl(sys.stderr.fileno(), xli.termios.TIOCGWINSZ, b"0000") if winsize is not None: xli.fcntl.ioctl(fd, xli.termios.TIOCSWINSZ, winsize) def _update_last_spec(last): env = XSH.env captured = last.captured last.last_in_pipeline = True if not captured: return callable_alias = callable(last.alias) if callable_alias: if last.cls is ProcProxy and captured == "hiddenobject": # a ProcProxy run using ![] should not be captured return else: cmds_cache = XSH.commands_cache thable = ( env.get("THREAD_SUBPROCS") and (captured != "hiddenobject" or env.get("XONSH_CAPTURE_ALWAYS")) and cmds_cache.predict_threadable(last.args) and cmds_cache.predict_threadable(last.cmd) ) if captured and thable: last.cls = PopenThread elif not thable: # foreground processes should use Popen last.threadable = False if captured == "object" or captured == "hiddenobject": # CommandPipeline objects should not pipe stdout, stderr return # cannot used PTY pipes for aliases, for some dark reason, # and must use normal pipes instead. use_tty = xp.ON_POSIX and not callable_alias # Do not set standard in! Popen is not a fan of redirections here # set standard out if last.stdout is not None: last.universal_newlines = True elif captured in STDOUT_CAPTURE_KINDS: last.universal_newlines = False r, w = os.pipe() last.stdout = safe_open(w, "wb") last.captured_stdout = safe_open(r, "rb") elif XSH.stdout_uncaptured is not None: last.universal_newlines = True last.stdout = XSH.stdout_uncaptured last.captured_stdout = last.stdout elif xp.ON_WINDOWS and not callable_alias: last.universal_newlines = True last.stdout = None # must truly stream on windows last.captured_stdout = ConsoleParallelReader(1) else: last.universal_newlines = True r, w = xli.pty.openpty() if use_tty else os.pipe() _safe_pipe_properties(w, use_tty=use_tty) last.stdout = safe_open(w, "w") _safe_pipe_properties(r, use_tty=use_tty) last.captured_stdout = safe_open(r, "r") # set standard error if last.stderr is not None: pass elif captured == "stdout": pass elif captured == "object": r, w = os.pipe() last.stderr = safe_open(w, "w") last.captured_stderr = safe_open(r, "r") elif XSH.stderr_uncaptured is not None: last.stderr = XSH.stderr_uncaptured last.captured_stderr = last.stderr elif xp.ON_WINDOWS and not callable_alias: last.universal_newlines = True last.stderr = None # must truly stream on windows else: r, w = xli.pty.openpty() if use_tty else os.pipe() _safe_pipe_properties(w, use_tty=use_tty) last.stderr = safe_open(w, "w") _safe_pipe_properties(r, use_tty=use_tty) last.captured_stderr = safe_open(r, "r") # redirect stdout to stderr, if we should if isinstance(last.stdout, int) and last.stdout == 2: # need to use private interface to avoid duplication. last._stdout = last.stderr # redirect stderr to stdout, if we should if callable_alias and last.stderr == subprocess.STDOUT: last._stderr = last.stdout last.captured_stderr = last.captured_stdout
[docs]def cmds_to_specs(cmds, captured=False, envs=None): """Converts a list of cmds to a list of SubprocSpec objects that are ready to be executed. """ # first build the subprocs independently and separate from the redirects i = 0 specs = [] redirects = [] for i, cmd in enumerate(cmds): if isinstance(cmd, str): redirects.append(cmd) else: env = envs[i] if envs is not None else None spec = SubprocSpec.build(cmd, captured=captured, env=env) spec.pipeline_index = i specs.append(spec) i += 1 # now modify the subprocs based on the redirects. for i, redirect in enumerate(redirects): if redirect == "|": # these should remain integer file descriptors, and not Python # file objects since they connect processes. r, w = os.pipe() specs[i].stdout = w specs[i + 1].stdin = r elif redirect == "&" and i == len(redirects) - 1: specs[i].background = True else: raise xt.XonshError(f"unrecognized redirect {redirect!r}") # Apply boundary conditions if not XSH.env.get("XONSH_CAPTURE_ALWAYS"): # Make sure sub-specs are always captured. # I.e. ![some_alias | grep x] $(some_alias) specs_to_capture = specs if captured in STDOUT_CAPTURE_KINDS else specs[:-1] for spec in specs_to_capture: if spec.env is None: spec.env = {"XONSH_CAPTURE_ALWAYS": True} else: spec.env.setdefault("XONSH_CAPTURE_ALWAYS", True) _update_last_spec(specs[-1]) return specs
def _should_set_title(): return XSH.env.get("XONSH_INTERACTIVE") and XSH.shell is not None
[docs]def run_subproc(cmds, captured=False, envs=None): """Runs a subprocess, in its many forms. This takes a list of 'commands,' which may be a list of command line arguments or a string, representing a special connecting character. For example:: $ ls | grep wakka is represented by the following cmds:: [['ls'], '|', ['grep', 'wakka']] Lastly, the captured argument affects only the last real command. """ if XSH.env.get("XONSH_TRACE_SUBPROC", False): tracer = XSH.env.get("XONSH_TRACE_SUBPROC_FUNC") if callable(tracer): tracer(cmds, captured=captured) else: print(f"TRACE SUBPROC: {cmds}, captured={captured}", file=sys.stderr) specs = cmds_to_specs(cmds, captured=captured, envs=envs) if _should_set_title(): # context manager updates the command information that gets # accessed by CurrentJobField when setting the terminal's title with XSH.env["PROMPT_FIELDS"]["current_job"].update_current_cmds(cmds): # remove current_job from prompt level cache XSH.env["PROMPT_FIELDS"].reset_key("current_job") # The terminal's title needs to be set before starting the # subprocess to avoid accidentally answering interactive questions # from commands such as `rm -i` (see #1436) XSH.shell.settitle() # run the subprocess return _run_specs(specs, cmds) else: return _run_specs(specs, cmds)
def _run_specs(specs, cmds): captured = specs[-1].captured if captured == "hiddenobject": command = HiddenCommandPipeline(specs) else: command = CommandPipeline(specs) proc = command.proc background = command.spec.background if not all(x.is_proxy for x in specs): xj.add_job( { "cmds": cmds, "pids": [i.pid for i in command.procs], "obj": proc, "bg": background, "pipeline": command, "pgrp": command.term_pgid, } ) # For some reason, some programs are in a stopped state when the flow # reaches this point, hence a SIGCONT should be sent to `proc` to make # sure that the shell doesn't hang. # See issue #2999 and the fix in PR #3000 resume_process(proc) # now figure out what we should return if captured == "object": return command # object can be returned even if backgrounding elif captured == "hiddenobject": if not background: command.end() return command elif background: return elif captured == "stdout": command.end() return command.output else: command.end() return