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aiturk-hermes-ide/tools/environments/base.py
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"""Base class for all Hermes execution environment backends.
Unified spawn-per-call model: every command spawns a fresh ``bash -c`` process.
A session snapshot (env vars, functions, aliases) is captured once at init and
re-sourced before each command. CWD persists via in-band stdout markers (remote)
or a temp file (local).
"""
import codecs
import json
import logging
import os
import re
import select
import shlex
import subprocess
import threading
import time
import uuid
from abc import ABC, abstractmethod
from collections import deque
from pathlib import Path
from typing import IO, Callable, Iterable, Protocol
from hermes_constants import get_hermes_home
from hermes_cli._subprocess_compat import windows_hide_flags
from tools.interrupt import is_interrupted, is_thread_interrupted
from tools.environments.path_utils import (
_SANDBOX_DIR_HASH_LEN,
_SANDBOX_DIR_MAX_LEN,
_SANDBOX_DIR_UNSAFE_RE,
sanitize_task_id_for_path,
)
logger = logging.getLogger(__name__)
# Opt-in debug tracing for the interrupt/activity/poll machinery. Set
# HERMES_DEBUG_INTERRUPT=1 to log loop entry/exit, periodic heartbeats, and
# every is_interrupted() state change from _wait_for_process. Off by default
# to avoid flooding production gateway logs.
_DEBUG_INTERRUPT = bool(os.getenv("HERMES_DEBUG_INTERRUPT"))
# Extra seconds the ``run_bounded_sync`` backstop waits past the inner
# ``_wait_for_process`` deadline. The inner poll loop is what returns
# partial output + returncode 124; this outer bound only exists for when
# that loop itself never returns (family A of #94285: a blocked wait
# that silently disables asyncio timers). Keep it small so a healthy
# timeout still comes from the inner path.
_EXECUTE_WAIT_BOUND_GRACE_S = 2.0
if _DEBUG_INTERRUPT:
# AIAgent's quiet_mode path (run_agent.py) forces the `tools` logger to
# ERROR on CLI startup, which would silently swallow every trace we emit.
# Force this module's own logger back to INFO so the trace is visible in
# agent.log regardless of quiet-mode. Scoped to the opt-in case only.
logger.setLevel(logging.INFO)
# Thread-local activity callback. The agent sets this before a tool call so
# long-running _wait_for_process loops can report liveness to the gateway.
_activity_callback_local = threading.local()
# Sentinel capacity for full-fidelity capture (internal consumers). Large
# enough that the collector never evicts in practice, keeping a single code
# path for both bounded and unbounded modes.
_UNBOUNDED_CAPTURE_CHARS = 2**63 - 1
class EnvironmentConnectionError(RuntimeError):
"""Infrastructure/connection-class failure of a terminal backend.
Raised when the backend itself is unreachable (SSH host down, Docker
daemon not running, remote file sync failing on a dead link) — never
for a command that merely exited nonzero. Subclassing RuntimeError
keeps every existing ``except RuntimeError`` catcher working.
``terminal_tool`` turns this into a structured ``status: "degraded"``
tool result (config gate ``terminal.degraded_mode: warn|fail``) so the
model gets an actionable reason + retry hint instead of a traceback.
The failed backend is never cached, so a later call retries from
scratch and simply works once the backend is reachable again.
"""
def __init__(self, reason: str, *, retry_hint: str = ""):
super().__init__(reason)
self.reason = reason
self.retry_hint = retry_hint or (
"This is an infrastructure failure, not a command failure. "
"Verify the backend is reachable (network, service running, "
"credentials), then retry the same command — recovery is "
"automatic once the backend is back."
)
class _BoundedOutputCollector:
"""Retain a bounded 40/60 head-tail window of streamed text.
When ``spill_path`` is set, the collector also tees the FULL stream to
that file once eviction begins (up to ``_SPILL_CAP_CHARS``), so a
truncated foreground result is recoverable without re-running the
command. Memory stays bounded either way — the spill is disk-only.
"""
# Hard ceiling on spill file size. Beyond this the file stops growing
# (marker appended); protects disk from pathological runaway output.
_SPILL_CAP_CHARS = 5_000_000
def __init__(self, max_chars: int, spill_path: "Path | None" = None):
self.max_chars = max(1, int(max_chars))
self._head_limit = int(self.max_chars * 0.4)
self._tail_limit = self.max_chars - self._head_limit
self._head: list[str] = []
self._tail: deque[str] = deque()
self._head_chars = 0
self._tail_chars = 0
self._total_chars = 0
self._lock = threading.Lock()
self._spill_path = spill_path
self._spill_fh: IO[str] | None = None
self._spill_chars = 0
self._spill_capped = False
def _maybe_spill(self, text: str) -> None:
"""Tee ``text`` to the spill file (opened lazily on first overflow)."""
if self._spill_path is None or self._spill_capped:
return
try:
if self._spill_fh is None:
from tools.spill_safety import ensure_spill_dir, open_exclusive
# Raw pre-redaction output: private perms + symlink-refusing
# exclusive create (a planted link must fail the spill, never
# redirect the write).
ensure_spill_dir(self._spill_path.parent, private=True)
self._spill_fh = open_exclusive(
self._spill_path, private=True, errors="replace"
)
# Backfill everything retained so far so the file holds the
# stream from byte 0, not just from the overflow point.
backlog = "".join(self._head) + "".join(self._tail)
self._spill_fh.write(backlog)
self._spill_chars = len(backlog)
budget = self._SPILL_CAP_CHARS - self._spill_chars
if budget <= 0 or len(text) > budget:
self._spill_fh.write(text[:max(0, budget)])
self._spill_fh.write("\n... [spill capped at 5,000,000 chars] ...\n")
self._spill_capped = True
else:
self._spill_fh.write(text)
self._spill_chars += len(text)
except OSError:
# Disk trouble must never break command execution.
self._spill_capped = True
def close_spill(self) -> "str | None":
"""Close the spill file and return its path if it was used."""
with self._lock:
if self._spill_fh is None:
return None
try:
self._spill_fh.close()
except OSError:
pass
self._spill_fh = None
return str(self._spill_path)
@property
def buffered_chars(self) -> int:
with self._lock:
return self._head_chars + self._tail_chars
@property
def total_chars(self) -> int:
with self._lock:
return self._total_chars
def append(self, text: str) -> None:
if not text:
return
with self._lock:
text_len = len(text)
# Spill tee: activates at the first overflow (backfilling what's
# retained so far), then mirrors every subsequent chunk.
if self._spill_path is not None and (
self._spill_fh is not None
or self._total_chars + text_len > self.max_chars
):
self._maybe_spill(text)
self._total_chars += text_len
start = 0
if self._head_chars < self._head_limit:
take = min(self._head_limit - self._head_chars, text_len)
if take:
self._head.append(text[:take])
self._head_chars += take
start = take
remaining = text_len - start
if remaining <= 0 or self._tail_limit <= 0:
return
if remaining >= self._tail_limit:
self._tail.clear()
self._tail.append(text[-self._tail_limit :])
self._tail_chars = self._tail_limit
return
chunk = text[start:]
self._tail.append(chunk)
self._tail_chars += len(chunk)
while self._tail_chars > self._tail_limit:
excess = self._tail_chars - self._tail_limit
first = self._tail[0]
if len(first) <= excess:
self._tail.popleft()
self._tail_chars -= len(first)
else:
self._tail[0] = first[excess:]
self._tail_chars -= excess
def render(self, *, suffix: str = "") -> str:
"""Render within ``max_chars``, preserving a required status suffix."""
with self._lock:
if len(suffix) >= self.max_chars:
return suffix[-self.max_chars :]
head = "".join(self._head)
tail = "".join(self._tail)
available = self.max_chars - len(suffix)
if self._total_chars <= available:
return head + tail + suffix
notice = ""
for _ in range(4):
content_budget = max(0, available - len(notice))
head_chars = int(content_budget * 0.4)
tail_chars = content_budget - head_chars
omitted = max(0, self._total_chars - head_chars - tail_chars)
updated = (
f"\n\n... [OUTPUT TRUNCATED - {omitted:,} chars omitted "
f"out of {self._total_chars:,} total] ...\n\n"
)
if updated == notice:
break
notice = updated
content_budget = max(0, available - len(notice))
head_chars = int(content_budget * 0.4)
tail_chars = content_budget - head_chars
rendered_tail = tail[-tail_chars:] if tail_chars else ""
return head[:head_chars] + notice[:available] + rendered_tail + suffix
def set_activity_callback(cb: Callable[[str], None] | None) -> None:
"""Register a callback that _wait_for_process fires periodically."""
_activity_callback_local.callback = cb
def get_activity_callback() -> Callable[[str], None] | None:
"""Return the thread-local activity callback (see ``set_activity_callback``).
Public accessor for callers outside this module that need to capture the
calling thread's callback before handing work to another thread (the
callback is thread-local, so a freshly spawned thread cannot read it
back) — e.g. the manual cron-run heartbeat (#76502).
"""
return getattr(_activity_callback_local, "callback", None)
def touch_activity_if_due(
state: dict,
label: str,
) -> None:
"""Fire the activity callback at most once every ``state['interval']`` seconds.
*state* must contain ``last_touch`` (monotonic timestamp) and ``start``
(monotonic timestamp of the operation start). An optional ``interval``
key overrides the default 10 s cadence.
Swallows all exceptions so callers don't need their own try/except.
"""
now = time.monotonic()
interval = state.get("interval", 10.0)
if now - state["last_touch"] < interval:
return
state["last_touch"] = now
try:
cb = get_activity_callback()
if cb:
elapsed = int(now - state["start"])
cb(f"{label} ({elapsed}s elapsed)")
except Exception:
pass
def get_sandbox_dir() -> Path:
"""Return the host-side root for all sandbox storage (Docker workspaces,
Singularity overlays/SIF cache, etc.).
Configurable via TERMINAL_SANDBOX_DIR. Defaults to {HERMES_HOME}/sandboxes/.
"""
custom = os.getenv("TERMINAL_SANDBOX_DIR")
if custom:
p = Path(custom)
else:
p = get_hermes_home() / "sandboxes"
p.mkdir(parents=True, exist_ok=True)
return p
# ---------------------------------------------------------------------------
# Shared constants and utilities
# ---------------------------------------------------------------------------
def _pipe_stdin(proc: subprocess.Popen, data: str) -> None:
"""Write *data* to proc.stdin on a daemon thread to avoid pipe-buffer deadlocks.
On Windows, text-mode stdin (``text=True`` / ``encoding="utf-8"``)
translates ``\\n`` → ``\\r\\n`` as the data flows through the pipe —
which corrupts every write_file / patch call because the bytes that
land on disk include injected carriage returns. The file IS created,
but every subsequent byte-count / content compare against the
caller's ``\\n``-only string fails.
Workaround: write through ``proc.stdin.buffer`` (the underlying byte
buffer), encoding to UTF-8 ourselves. That bypasses Python's
newline translation entirely on every platform. No behaviour change
on POSIX — the byte sequence is identical to what text-mode would
produce there.
Encoding uses ``errors="surrogateescape"`` — the exact inverse of the
surrogateescape decode, so original bytes are restored. For
surrogate-free strings it is byte-identical to strict UTF-8.
Surrogates outside the round-trip range U+DC80U+DCFF raise and are
recorded on ``proc._hermes_stdin_errors`` while stdin is still closed
in ``finally`` so the child sees EOF instead of hanging;
``_wait_for_process`` reads the recorded error and surfaces it as
``stdin_error`` on the result.
"""
errors: list[BaseException] = []
proc._hermes_stdin_errors = errors
def _write():
if proc.stdin is None:
errors.append(RuntimeError("process stdin unavailable"))
return
# Resolve the target BEFORE encoding: a failed encode must still
# reach the finally-close, or the child hangs on EOF forever.
target = getattr(proc.stdin, "buffer", proc.stdin)
try:
raw = data.encode("utf-8", "surrogateescape") if isinstance(data, str) else data
written = target.write(raw)
if written != len(raw):
# Buffered writers normally complete or raise; a short write
# is a real failure and must be surfaced, not swallowed.
raise RuntimeError(f"short stdin write: {written} of {len(raw)} bytes")
except (BrokenPipeError, OSError):
pass # child closed stdin early — normal
except Exception as exc:
# Only reachable with surrogates outside the surrogateescape
# round-trip range (e.g. a literal U+D800). Record it so
# _wait_for_process can surface it instead of a silent false
# success.
errors.append(exc)
finally:
try:
target.close()
except Exception:
pass
thread = threading.Thread(target=_write, daemon=True)
proc._hermes_stdin_thread = thread
thread.start()
def _popen_bash(
cmd: list[str], stdin_data: str | None = None, **kwargs
) -> subprocess.Popen:
"""Spawn a subprocess with standard stdout/stderr/stdin setup.
If *stdin_data* is provided, writes it asynchronously via :func:`_pipe_stdin`.
Backends with special Popen needs (e.g. local's ``preexec_fn``) can bypass
this and call :func:`_pipe_stdin` directly.
"""
kwargs.setdefault("creationflags", windows_hide_flags())
proc = subprocess.Popen(
cmd,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
stdin=subprocess.PIPE if stdin_data is not None else subprocess.DEVNULL,
text=True, encoding="utf-8", errors="replace",
**kwargs,
)
if stdin_data is not None:
_pipe_stdin(proc, stdin_data)
return proc
def _load_json_store(path: Path) -> dict:
"""Load a JSON file as a dict, returning ``{}`` on any error."""
if path.exists():
try:
return json.loads(path.read_text(encoding="utf-8"))
except Exception:
pass
return {}
def _save_json_store(path: Path, data: dict) -> None:
"""Write *data* as pretty-printed JSON to *path*."""
path.parent.mkdir(parents=True, exist_ok=True)
path.write_text(json.dumps(data, indent=2), encoding="utf-8")
def _file_mtime_key(host_path: str) -> tuple[float, int] | None:
"""Return ``(mtime, size)`` for cache comparison, or ``None`` if unreadable."""
try:
st = Path(host_path).stat()
return (st.st_mtime, st.st_size)
except OSError:
return None
# ---------------------------------------------------------------------------
# ProcessHandle protocol
# ---------------------------------------------------------------------------
class ProcessHandle(Protocol):
"""Duck type that every backend's _run_bash() must return.
subprocess.Popen satisfies this natively. SDK backends (Modal, Daytona)
return _ThreadedProcessHandle which adapts their blocking calls.
"""
def poll(self) -> int | None: ...
def kill(self) -> None: ...
def wait(self, timeout: float | None = None) -> int: ...
@property
def stdout(self) -> IO[str] | None: ...
@property
def returncode(self) -> int | None: ...
class _ThreadedProcessHandle:
"""Adapter for SDK backends (Modal, Daytona) that have no real subprocess.
Wraps a blocking ``exec_fn() -> (output_str, exit_code)`` in a background
thread and exposes a ProcessHandle-compatible interface. An optional
``cancel_fn`` is invoked on ``kill()`` for backend-specific cancellation
(e.g. Modal sandbox.terminate, Daytona sandbox.stop).
"""
def __init__(
self,
exec_fn: Callable[[], tuple[str, int]],
cancel_fn: Callable[[], None] | None = None,
):
self._cancel_fn = cancel_fn
self._done = threading.Event()
self._returncode: int | None = None
self._error: Exception | None = None
# Pipe for stdout — drain thread in _wait_for_process reads the read end.
read_fd, write_fd = os.pipe()
self._stdout = os.fdopen(read_fd, "r", encoding="utf-8", errors="replace")
self._write_fd = write_fd
def _worker():
try:
output, exit_code = exec_fn()
self._returncode = exit_code
# Write output into the pipe so drain thread picks it up.
try:
os.write(self._write_fd, output.encode("utf-8", errors="replace"))
except OSError:
pass
except Exception as exc:
self._error = exc
self._returncode = 1
finally:
try:
os.close(self._write_fd)
except OSError:
pass
self._done.set()
t = threading.Thread(target=_worker, daemon=True)
t.start()
@property
def stdout(self):
return self._stdout
@property
def returncode(self) -> int | None:
return self._returncode
def poll(self) -> int | None:
return self._returncode if self._done.is_set() else None
def kill(self):
if self._cancel_fn:
try:
self._cancel_fn()
except Exception:
pass
def wait(self, timeout: float | None = None) -> int:
self._done.wait(timeout=timeout)
return self._returncode
# ---------------------------------------------------------------------------
# CWD marker for remote backends
# ---------------------------------------------------------------------------
def _cwd_marker(session_id: str) -> str:
return f"__HERMES_CWD_{session_id}__"
# Per-session variables that the gateway bridges freshly onto every command's
# process environment (via tools/environments/local._inject_session_context_env,
# reading gateway.session_context._VAR_MAP). They must NEVER be persisted into
# the shared bash session snapshot: a single long-lived backend serves many
# concurrent sessions (the messaging gateway, TUI, desktop/web dashboard all
# collapse the terminal to one "default" environment), so ``export -p`` dumping
# the FIRST session's HERMES_SESSION_ID into the snapshot makes every LATER
# session ``source`` that stale value and see a FOREIGN session's identity —
# overriding the correct per-command Popen env (issue: cross-session
# HERMES_SESSION_ID leak via the shared snapshot). Stripping them from the
# snapshot is safe because they are re-injected on every command; a snapshot
# should only carry the user's own shell state (PATH, functions, exports they
# set), not Hermes' per-turn session identity.
#
# Kept in sync with gateway.session_context._VAR_MAP: every bridged name starts
# with one of these prefixes (or is HERMES_UI_SESSION_ID). Used by unit tests
# as the Python-side contract for the exclusion set; the dump path unsets by
# name/prefix instead of grepping declare lines (see below / issue #71296).
_SNAPSHOT_EXCLUDED_ENV_REGEX = (
"^declare -x (HERMES_SESSION_|HERMES_UI_SESSION_ID|HERMES_CRON_AUTO_DELIVER_|"
"HERMES_CRON_SESSION|HERMES_BROWSER_CONTROL_)"
)
_SHELL_ENV_NAME_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
def _export_dump_excluding_session_vars(
tmp_path: str,
excluded_names: Iterable[str] = (),
) -> str:
"""Return a shell snippet that dumps ``export -p`` to *tmp_path* minus the
per-session bridged vars (see ``_SNAPSHOT_EXCLUDED_ENV_REGEX``) and any
additional names supplied by the caller.
Unset the bridged vars in a subshell *before* ``export -p``. A line-based
``grep -vE`` filter is unsafe: bash 3.2 prints a value containing a newline
as a multi-line ``declare -x NAME="…`` block, so only the opener matches the
regex and continuation lines (e.g. ``curl … | bash #`` smuggled into a
Matrix room/display name via ``HERMES_SESSION_CHAT_NAME``) land in the
snapshot and execute on the next ``source`` (issue #71296). Unsetting first
means ``export -p`` never emits those vars — including any continuation
lines. ``|| true`` keeps the success contract for callers that chain on it.
The dump MUST be wrapped in a brace group with the redirection applied to
the group. *tmp_path* is typically a shell-variable expansion (a
mktemp-allocated per-writer temp name); a redirection attached to a
pipeline segment would expand it inside that segment's subshell,
potentially inconsistently with the parent that expands the follow-up
``mv``. The brace-group redirect is expanded in the current shell,
keeping both expansions consistent.
"""
# ${!PREFIX*} is bash 3.2+ name-prefix expansion; empty matches are fine
# because ``unset`` with only missing names is ignored under 2>/dev/null.
# Quote caller-provided names so malformed configuration can never become
# shell syntax. Valid environment names remain unquoted by shlex.quote().
safe_names = {
name for name in excluded_names
if isinstance(name, str) and name
}
extra_unset = " ".join(shlex.quote(name) for name in sorted(safe_names))
if extra_unset:
extra_unset = f" {extra_unset}"
return (
"{ ( "
"unset ${!HERMES_SESSION_*} ${!HERMES_CRON_AUTO_DELIVER_*} "
"${!HERMES_BROWSER_CONTROL_*} "
# AI_AGENT / HERMES_AGENT are per-command attribution markers
# (re-exported by every _wrap_command with outer-harness-preserving
# ${VAR:-default} semantics). Persisting them into the snapshot
# would make the FIRST command's value override a later outer
# harness value arriving via the process env, exactly like the
# session-var leak this dump already guards against.
"AI_AGENT HERMES_AGENT "
f"HERMES_UI_SESSION_ID{extra_unset} 2>/dev/null; "
"export -p; "
") || true; } "
f"> {tmp_path}"
)
# ---------------------------------------------------------------------------
# BaseEnvironment
# ---------------------------------------------------------------------------
class BaseEnvironment(ABC):
"""Common interface and unified execution flow for all Hermes backends.
Subclasses implement ``_run_bash()`` and ``cleanup()``. The base class
provides ``execute()`` with session snapshot sourcing, CWD tracking,
interrupt handling, and timeout enforcement.
"""
# Subclasses that embed stdin as a heredoc (Modal, Daytona) set this.
_stdin_mode: str = "pipe" # "pipe" or "heredoc"
# True only when commands execute on the SAME host as the Hermes process
# (LocalEnvironment). Controller-host facts (sys.platform, Path.home())
# only describe the execution target when this is True — remote/container
# backends must not inherit controller-side platform behavior (e.g. the
# macOS TCC search pruning in tools/file_operations.py).
is_local: bool = False
# Snapshot creation timeout (override for slow cold-starts).
_snapshot_timeout: int = 30
# Local and Docker override this because they resolve allowlisted values
# through the active profile scope. Other backends keep their existing
# snapshot semantics until they implement the same resolver contract.
_profile_scoped_passthrough: bool = False
def get_temp_dir(self) -> str:
"""Return the backend temp directory used for session artifacts.
Most sandboxed backends use ``/tmp`` inside the target environment.
LocalEnvironment overrides this on platforms like Termux where ``/tmp``
may be missing and ``TMPDIR`` is the portable writable location.
"""
return "/tmp"
def __init__(self, cwd: str, timeout: int, env: dict = None):
self.cwd = cwd
self.timeout = timeout
self.env = env or {}
self._session_id = uuid.uuid4().hex[:12]
temp_dir = self.get_temp_dir().rstrip("/") or "/"
self._snapshot_path = f"{temp_dir}/hermes-snap-{self._session_id}.sh"
self._cwd_file = f"{temp_dir}/hermes-cwd-{self._session_id}.txt"
self._cwd_marker = _cwd_marker(self._session_id)
self._snapshot_ready = False
self._snapshot_passthrough_names: set[str] = set()
# When True, login bash is unusable (e.g. broken Git-for-Windows
# ``Directory \\drivers\\etc`` startup) so execute() must not fall
# back to ``bash -l`` per command — use non-login ``bash -c`` instead.
self._prefer_nonlogin = False
# ------------------------------------------------------------------
# Abstract methods
# ------------------------------------------------------------------
def _run_bash(
self,
cmd_string: str,
*,
login: bool = False,
timeout: int = 120,
stdin_data: str | None = None,
) -> ProcessHandle:
"""Spawn a bash process to run *cmd_string*.
Returns a ProcessHandle (subprocess.Popen or _ThreadedProcessHandle).
Must be overridden by every backend.
"""
raise NotImplementedError(f"{type(self).__name__} must implement _run_bash()")
@abstractmethod
def cleanup(self):
"""Release backend resources (container, instance, connection)."""
...
# ------------------------------------------------------------------
# Session snapshot (init_session)
# ------------------------------------------------------------------
def _additional_profile_scoped_passthrough_names(self) -> Iterable[str]:
"""Return backend-specific names that must not persist in snapshots."""
return ()
def _snapshot_excluded_passthrough_names(self) -> tuple[str, ...]:
"""Return profile-scoped names that must not persist in the snapshot.
The set is monotonic for the environment lifetime. A skill/config
allowlist can be cleared after a value was captured; retaining the
exclusion prevents that old value from becoming visible to a later
profile through the shared snapshot.
"""
if not self._profile_scoped_passthrough:
return ()
try:
from agent.secret_scope import is_multiplex_active
if is_multiplex_active():
from tools.env_passthrough import get_all_passthrough
names = (
*get_all_passthrough(),
*self._additional_profile_scoped_passthrough_names(),
)
self._snapshot_passthrough_names.update(
name
for name in names
if isinstance(name, str) and _SHELL_ENV_NAME_RE.fullmatch(name)
)
except Exception:
logger.debug(
"Could not refresh profile-scoped snapshot exclusions",
exc_info=True,
)
return tuple(sorted(self._snapshot_passthrough_names))
def init_session(self):
"""Capture login shell environment into a snapshot file.
Called once after backend construction. On success, sets
``_snapshot_ready = True`` so subsequent commands source the snapshot
instead of running with ``bash -l``.
"""
# Full capture: env vars, functions, aliases, shell options.
# Restore configured cwd after login shell profile scripts, which may
# change the working directory (e.g. bashrc `cd ~`). Without this,
# pwd -P captures the profile's directory, not terminal.cwd.
# Route through ``_quote_cwd_for_cd`` (not a bare ``shlex.quote``) so
# the Windows subclass override converts a native ``C:\Users\x`` cwd to
# the Git-Bash ``/c/Users/x`` form the bootstrap ``cd`` can resolve.
# Without this the snapshot bootstrap ``cd`` below fails on Windows and
# ``pwd -P`` captures the login shell's directory, not ``terminal.cwd``.
_quoted_cwd = self._quote_cwd_for_cd(self.cwd)
# Quote snapshot / cwd-file paths via ``_quote_shell_path`` so the
# LocalEnvironment override can rewrite ``C:/...`` (and mixed
# ``/c/Users\\...``) to ``/c/...`` before quoting — bare drive paths
# in the bootstrap script trip MSYS into the
# ``Directory \\drivers\\etc does not exist`` failure class.
# On POSIX this is plain ``shlex.quote``.
_quoted_snap = self._quote_shell_path(self._snapshot_path)
# Use atomic file replacement: assemble the snapshot in a temp file,
# then mv it over the final path. This prevents concurrent source()
# calls from reading a half-written snapshot when another terminal
# command finishes and rewrites the env vars (issue #38249). `mv` is
# atomic on POSIX when src and dest are on the same filesystem, so
# source() either sees the old complete snapshot or the new complete
# one — never a partial/truncated file.
#
# The temp name MUST be unique per concurrent writer. ``$$`` is the
# bash PID, but in ``&``-launched subshells (how concurrent terminal
# calls run) ``$$`` stays the *parent* shell's PID — so two concurrent
# writers would pick the SAME temp name, clobber each other's temp
# mid-write, and mv would then publish a torn file (the corruption is
# only narrowed, not closed). ``$BASHPID`` would be unique per writer,
# but macOS ships bash 3.2 which does NOT provide it — the name expands
# empty there, so every writer shares one temp path and the race is
# back. ``mktemp`` allocates a per-writer unique path portably across
# bash versions. The template is shell-quoted (Windows/Git-Bash drive
# letters, spaces) and the resulting path lives in a shell variable so
# every later expansion is consistent.
_snap_tmp_template = self._quote_shell_path(self._snapshot_path + ".tmp.XXXXXXXXXX")
_snap_tmp = '"$__hermes_snap_tmp"'
snapshot_excluded = self._snapshot_excluded_passthrough_names()
bootstrap = (
f"umask 077\n"
f"__hermes_snap_tmp=$(mktemp {_snap_tmp_template}) || exit 1\n"
f"{_export_dump_excluding_session_vars(_snap_tmp, snapshot_excluded)}\n"
# Dump function definitions, filtering out private (``_``-prefixed)
# helpers — mainly bash-completion internals (``_git``, ``_make``…)
# — by NAME, not by line. A naive ``declare -f | grep -vE '^_[^_]'``
# is line-based: it strips the function *header* line but leaves the
# orphaned ``{ … }`` body behind, which corrupts the snapshot and
# makes every sourced command fail (e.g. exit 127). Selecting the
# wanted names with ``declare -F`` first, then dumping only those
# whole definitions, preserves the filter's intent without ever
# tearing a function body. The non-empty guard matters: bare
# ``declare -f`` with no name args dumps ALL functions, so an empty
# name list (only private funcs present) would otherwise leak the
# very functions we meant to drop.
f"__hermes_fns=$(declare -F | awk '{{print $3}}' | grep -vE '^_[^_]') || true\n"
f"[ -n \"$__hermes_fns\" ] && declare -f $__hermes_fns "
f">> {_snap_tmp} 2>/dev/null || true\n"
f"alias -p >> {_snap_tmp}\n"
f"echo 'shopt -s expand_aliases' >> {_snap_tmp}\n"
f"echo 'set +e' >> {_snap_tmp}\n"
f"echo 'set +u' >> {_snap_tmp}\n"
# Publish atomically only if assembly succeeded; otherwise drop the
# partial temp rather than leave it to be sourced or orphaned.
f"mv -f {_snap_tmp} {_quoted_snap} || rm -f {_snap_tmp}\n"
f"builtin cd -- {_quoted_cwd} 2>/dev/null || true\n"
f"printf '\\n{self._cwd_marker}%s{self._cwd_marker}\\n' \"$(pwd -P)\"\n"
)
try:
proc = self._run_bash(bootstrap, login=True, timeout=self._snapshot_timeout)
result = self._wait_for_process(proc, timeout=self._snapshot_timeout)
if int(result.get("returncode") or 0) != 0:
raise RuntimeError(
f"snapshot bootstrap failed with exit code {result.get('returncode')}"
)
self._snapshot_ready = True
self._update_cwd(result)
logger.info(
"Session snapshot created (session=%s, cwd=%s)",
self._session_id,
self.cwd,
)
except Exception as exc:
self._snapshot_ready = False
# Default fallback is bash -l per command so PATH/nvm/etc still
# load. If login itself is dead (classic Windows Git Bash
# ``Directory \\drivers\\etc does not exist``), that fallback
# would brick every tool — prefer non-login bash -c instead.
detail = str(exc)
prefer_nonlogin = False
try:
probe = self._run_bash("true", login=False, timeout=min(15, self._snapshot_timeout))
probe_result = self._wait_for_process(probe, timeout=min(15, self._snapshot_timeout))
prefer_nonlogin = int(probe_result.get("returncode") or 0) == 0
if not prefer_nonlogin:
detail = (probe_result.get("stdout") or detail).strip() or detail
except Exception as probe_exc:
detail = f"{detail}; non-login probe: {probe_exc}"
self._prefer_nonlogin = prefer_nonlogin
if prefer_nonlogin:
logger.warning(
"init_session failed (session=%s): %s — "
"login bash unusable; falling back to non-login bash -c",
self._session_id,
exc,
)
else:
logger.warning(
"init_session failed (session=%s): %s — "
"falling back to bash -l per command",
self._session_id,
detail,
)
# ------------------------------------------------------------------
# Command wrapping
# ------------------------------------------------------------------
@staticmethod
def _quote_cwd_for_cd(cwd: str) -> str:
"""Quote a ``cd`` target while preserving ``~`` expansion."""
if cwd == "~":
return cwd
if cwd == "~/":
return "$HOME"
if cwd.startswith("~/"):
return f"$HOME/{shlex.quote(cwd[2:])}"
return shlex.quote(cwd)
def _quote_shell_path(self, path: str) -> str:
"""Quote *path* for interpolation into a bash script.
LocalEnvironment overrides this to rewrite native/mixed Windows
paths to ``/c/...`` before quoting. Remote backends leave paths
as-is (they already speak POSIX).
"""
return shlex.quote(path)
def _wrap_command(self, command: str, cwd: str) -> str:
"""Build the full bash script that sources snapshot, cd's, runs command,
re-dumps env vars, and emits CWD markers."""
escaped = command.replace("'", "'\\''")
# Quote the snapshot path (see init_session — LocalEnvironment
# rewrites ``C:/...`` to ``/c/...`` so MSYS doesn't mangle it).
_quoted_snap = self._quote_shell_path(self._snapshot_path)
# Use atomic file replacement for env snapshot updates (issue #38249).
# Assemble into a per-writer-unique temp file, then mv to atomically
# replace the snapshot so concurrent source() calls never read a
# truncated/half-written file. ``mktemp`` is used instead of
# ``$BASHPID``/``$$`` because macOS bash 3.2 lacks ``$BASHPID`` (it
# expands empty, collapsing every writer onto one temp name) and ``$$``
# is shared by ``&``-launched subshells. Template shell-quoted
# (Windows/spaces); the allocated path lives in a shell variable.
_snap_tmp_template = self._quote_shell_path(self._snapshot_path + ".tmp.XXXXXXXXXX")
_snap_tmp = '"$__hermes_snap_tmp"'
parts = []
passthrough_names = self._snapshot_excluded_passthrough_names()
# A shared snapshot may contain the previous profile's value. Save
# the current process environment before sourcing it, then restore the
# current profile's value (or unset the name) immediately afterwards.
# Values stay in environment memory and never enter the shell command
# string, so secrets are not exposed through process arguments/logs.
saved_names: list[tuple[str, str, str]] = []
for name in passthrough_names:
marker = f"_HERMES_RUNTIME_PASSTHROUGH_{name}"
present = f"{marker}_PRESENT"
value = f"{marker}_VALUE"
saved_names.append((name, present, value))
parts.append(f"{present}=${{{name}+x}}")
parts.append(f"{value}=${{{name}-}}")
# Source snapshot (env vars from previous commands).
# Redirect stdout to /dev/null: on macOS (bash 3.2 and certain
# Homebrew bash builds) sourcing a file containing ``declare -x``
# can emit the declarations to stdout, leaking ~60 lines of env
# vars into every tool response (issue #15459). Linux bash is
# silent here, but the redirect is harmless.
if self._snapshot_ready:
parts.append(
f"source {_quoted_snap} >/dev/null 2>&1 || true"
)
for name, present, value in saved_names:
parts.append(
f'if [ "${present}" = x ]; then export {name}="${value}"; '
f'else unset {name}; fi'
)
parts.append(f"unset {present} {value}")
# Harness attribution: every tool subprocess advertises that it runs
# under Hermes via the cross-agent ``AI_AGENT`` standard (read by e.g.
# huggingface_hub's agent detection) plus the Hermes-specific
# ``HERMES_AGENT`` marker. The value MUST equal our id in the public
# agent-harness registry (``hermes-agent`` — see huggingface.js
# ``agent-harnesses.ts``); standard-var matching is exact, so any other
# value is reported as "unknown". Setting it here (rather than only in
# the host process env) is what carries the marker into REMOTE backends
# (Docker/SSH/Modal/Daytona/Singularity/Vercel), whose exec env is not
# inherited from the Hermes process. ``${VAR:-default}`` semantics:
# never clobber an outer harness value that arrived via the inherited
# process env (Hermes running inside another agent's terminal).
parts.append(
'export AI_AGENT="${AI_AGENT:-hermes-agent}" '
'HERMES_AGENT="${HERMES_AGENT:-true}"'
)
# Non-interactive pager defaults: git log/diff/branch and similar
# pager-happy tools hang a captured (non-TTY writing to a pipe is
# fine, but PTY mode IS a TTY) or PTY-backed command waiting for `q`.
# GIT_PAGER=cat neutralizes git specifically; PAGER=cat catches the
# long tail (man, systemctl, psql, ...). ${VAR:-default} semantics:
# a user who exported their own pager in the session keeps it.
parts.append(
'export GIT_PAGER="${GIT_PAGER:-cat}" PAGER="${PAGER:-cat}"'
)
# Preserve bare ``~`` expansion, but rewrite ``~/...`` through
# ``$HOME`` so suffixes with spaces remain a single shell word.
quoted_cwd = self._quote_cwd_for_cd(cwd)
# ``--`` keeps hyphen-prefixed directory names from being parsed as options.
parts.append(f"builtin cd -- {quoted_cwd} || exit 126")
# Run the actual command
parts.append(f"eval '{escaped}'")
parts.append("__hermes_ec=$?")
# Restrict Hermes metadata files without changing the user's command
# umask. Snapshot files may contain env-carried secrets.
parts.append("umask 077")
# Re-dump env vars to snapshot (atomic replacement to avoid races).
# Chain mv on the export succeeding so a failed/partial dump never
# replaces a good snapshot; drop the temp on failure so it isn't
# orphaned (cleaned up wholesale in LocalEnvironment.cleanup too).
# NOTE: the temp path is allocated with mktemp into a shell variable
# first — the redirection inside _export_dump_excluding_session_vars is
# attached to a brace group so the variable expands in the same shell
# that later expands the ``mv`` operand, keeping both consistent.
if self._snapshot_ready:
parts.append(
f"__hermes_snap_tmp=$(mktemp {_snap_tmp_template}) && "
f"{{ {_export_dump_excluding_session_vars(_snap_tmp, passthrough_names)} "
f"&& mv -f {_snap_tmp} {_quoted_snap}; }} "
f"2>/dev/null || rm -f {_snap_tmp} 2>/dev/null || true"
)
# Emit the CWD stdout marker; all backends (including local, since
# PR #63255) parse it from output — no temp-file write needed.
# Use a distinct line for the marker. The leading \n ensures
# the marker starts on its own line even if the command doesn't
# end with a newline (e.g. printf 'exact'). We'll strip this
# injected newline in _extract_cwd_from_output.
parts.append(
f"printf '\\n{self._cwd_marker}%s{self._cwd_marker}\\n' \"$(pwd -P)\""
)
parts.append("exit $__hermes_ec")
return "\n".join(parts)
# ------------------------------------------------------------------
# Stdin heredoc embedding (for SDK backends)
# ------------------------------------------------------------------
@staticmethod
def _embed_stdin_heredoc(command: str, stdin_data: str) -> str:
"""Append stdin_data as a shell heredoc to the command string."""
delimiter = f"HERMES_STDIN_{uuid.uuid4().hex[:12]}"
return f"{command} << '{delimiter}'\n{stdin_data}\n{delimiter}"
# ------------------------------------------------------------------
# Process lifecycle
# ------------------------------------------------------------------
def _wait_for_process(
self,
proc: ProcessHandle,
timeout: int = 120,
*,
bounded_capture: bool = False,
watch_interrupt_tid: int | None = None,
) -> dict:
"""Poll-based wait with interrupt checking and stdout draining.
Shared across all backends — not overridden.
``bounded_capture=True`` (foreground terminal-tool path only) retains
at most ``tool_output.max_bytes`` of output in a head/tail window
while draining, so a verbose subprocess cannot OOM the process
(#64435). The default (False) preserves full-fidelity capture for
internal consumers — file-operation ``cat`` reads feeding the patch
engine, code-execution RPC reads, log reads — where truncation would
corrupt data.
Fires the ``activity_callback`` (if set on this instance) every 10s
while the process is running so the gateway's inactivity timeout
doesn't kill long-running commands.
``watch_interrupt_tid`` is the tool-worker thread that submitted this
wait. ``execute()`` may move the wait onto a ``run_bounded_sync``
worker; ``/stop`` still interrupts the original worker tid, so the
poll loop must honor that bit as well as the current thread's.
Also wraps the poll loop in a ``try/finally`` that guarantees we
call ``self._kill_process(proc)`` if we exit via ``KeyboardInterrupt``
or ``SystemExit``. Without this, the local backend (which spawns
subprocesses with ``os.setsid`` into their own process group) leaves
an orphan with ``PPID=1`` when python is shut down mid-tool — the
``sleep 300``-survives-30-min bug Physikal and I both hit.
"""
if bounded_capture:
try:
from tools.tool_output_limits import get_max_bytes
capture_limit = get_max_bytes()
except Exception:
capture_limit = 50_000
else:
# Full fidelity: effectively unbounded collector (single head
# segment, no eviction) so behavior matches the historical
# accumulate-everything semantics.
capture_limit = _UNBOUNDED_CAPTURE_CHARS
spill_path = None
if bounded_capture:
# Foreground terminal path: tee overflow to a spill file so a
# truncated result is recoverable without re-running (the file
# only gets created if output actually exceeds the cap).
try:
spill_dir = get_hermes_home() / "cache" / "terminal-output"
spill_path = spill_dir / f"out-{int(time.time())}-{os.getpid()}-{id(proc) & 0xffff:x}.log"
# Opportunistic cleanup of spills older than 7 days.
if spill_dir.is_dir():
cutoff = time.time() - 7 * 86400
for old in spill_dir.glob("out-*.log"):
try:
if old.stat().st_mtime < cutoff:
old.unlink()
except OSError:
pass
except Exception:
spill_path = None
output = _BoundedOutputCollector(capture_limit, spill_path=spill_path)
# Non-blocking drain via select().
#
# The old pattern — ``for line in proc.stdout`` — blocks on
# ``readline()`` until the pipe reaches EOF. When the user's command
# backgrounds a process (``cmd &``, ``setsid cmd & disown``, etc.),
# that backgrounded grandchild inherits the write-end of our stdout
# pipe via ``fork()``. Even after ``bash`` itself exits, the pipe
# stays open because the grandchild still holds it — so the drain
# thread never returns and the tool hangs for the full lifetime of
# the grandchild (issue #8340: users reported indefinite hangs when
# restarting uvicorn with ``setsid ... & disown``).
#
# The fix: select() with a short poll interval, and stop draining
# shortly after ``bash`` exits even if the pipe hasn't EOF'd yet.
# Any output the grandchild writes after that point goes to an
# orphaned pipe (harmless — the kernel reaps it when our end closes).
#
# Decoding: we ``os.read()`` raw bytes in fixed-size chunks (4096)
# so a single multibyte UTF-8 character can split across reads. An
# incremental decoder buffers partial sequences across chunks, and
# ``errors="replace"`` mirrors the baseline ``TextIOWrapper`` (which
# was constructed with ``encoding="utf-8", errors="replace"`` on
# ``Popen``) so binary or mis-encoded output is preserved with
# U+FFFD substitution rather than clobbering the whole buffer.
decoder = codecs.getincrementaldecoder("utf-8")(errors="replace")
def _drain_iterable(stream):
# Fallback path: ``stream`` is not backed by a real OS file
# descriptor (no usable ``fileno()``). This covers in-memory
# ProcessHandle adapters that expose stdout as a plain iterator of
# already-collected output (the legacy ``for line in proc.stdout``
# contract) rather than a live pipe. Iterate it to EOF. Without
# this, the drain thread would raise an unhandled exception and die
# silently, losing all of the process's output.
try:
for piece in stream:
if piece is None:
continue
if isinstance(piece, bytes):
output.append(decoder.decode(piece))
else:
output.append(str(piece))
except Exception:
pass
finally:
try:
tail = decoder.decode(b"", final=True)
if tail:
output.append(tail)
except Exception:
pass
def _drain():
# Resolve a real OS file descriptor up front. Real subprocesses and
# the SDK ``_ThreadedProcessHandle`` (os.pipe-backed) both return an
# integer fd here. Mocks / iterator-style stdout streams either lack
# ``fileno()`` entirely or return a non-integer — in that case fall
# back to draining the stream as an iterable instead of crashing the
# thread (issue: 'list_iterator' object has no attribute 'fileno').
stream = proc.stdout
if stream is None:
return
fileno = getattr(stream, "fileno", None)
try:
fd = fileno() if callable(fileno) else None
except Exception:
fd = None
if not isinstance(fd, int) or fd < 0:
_drain_iterable(stream)
return
# select.select does NOT work on pipe fds on Windows (only sockets).
# Use blocking os.read in a daemon thread instead — safe because
# EOF arrives promptly when bash exits.
if os.name == "nt":
try:
while True:
chunk = os.read(fd, 4096)
if not chunk:
break
output.append(decoder.decode(chunk))
except (ValueError, OSError):
pass
finally:
try:
tail = decoder.decode(b"", final=True)
if tail:
output.append(tail)
except Exception:
pass
return
idle_after_exit = 0
try:
while True:
try:
ready, _, _ = select.select([fd], [], [], 0.1)
except (ValueError, OSError):
break # fd already closed
if ready:
try:
chunk = os.read(fd, 4096)
except (ValueError, OSError):
break
if not chunk:
break # true EOF — all writers closed
output.append(decoder.decode(chunk))
idle_after_exit = 0
elif proc.poll() is not None:
# bash is gone and the pipe was idle for ~100ms. Give
# it two more cycles to catch any buffered tail, then
# stop — otherwise we wait forever on a grandchild pipe.
idle_after_exit += 1
if idle_after_exit >= 3:
break
finally:
# Flush any bytes buffered mid-sequence. With ``errors="replace"``
# this emits U+FFFD for any final incomplete sequence rather than
# raising.
try:
tail = decoder.decode(b"", final=True)
if tail:
output.append(tail)
except Exception:
pass
drain_thread = threading.Thread(target=_drain, daemon=True)
drain_thread.start()
deadline = time.monotonic() + timeout
_now = time.monotonic()
_activity_state = {
"last_touch": _now,
"start": _now,
}
# --- Debug tracing (opt-in via HERMES_DEBUG_INTERRUPT=1) -------------
# Captures loop entry/exit, interrupt state changes, and periodic
# heartbeats so we can diagnose "agent never sees the interrupt"
# reports without reproducing locally.
_tid = threading.current_thread().ident
_pid = getattr(proc, "pid", None)
_iter_count = 0
_last_heartbeat = _now
_last_interrupt_state = False
_cb_was_none = get_activity_callback() is None
if _DEBUG_INTERRUPT:
logger.info(
"[interrupt-debug] _wait_for_process ENTER tid=%s pid=%s "
"timeout=%ss activity_cb=%s initial_interrupt=%s",
_tid, _pid, timeout,
"set" if not _cb_was_none else "MISSING",
is_interrupted(),
)
try:
_poll_sleep = 0.005
while proc.poll() is None:
_iter_count += 1
if is_interrupted() or is_thread_interrupted(watch_interrupt_tid):
if _DEBUG_INTERRUPT:
logger.info(
"[interrupt-debug] _wait_for_process INTERRUPT DETECTED "
"tid=%s pid=%s iter=%d elapsed=%.1fs — killing process group",
_tid, _pid, _iter_count, time.monotonic() - _activity_state["start"],
)
self._kill_process(proc)
drain_thread.join(timeout=2)
return self._finalize_wait_result(
output,
output.render(suffix="\n[Command interrupted]"),
130,
)
if time.monotonic() > deadline:
if _DEBUG_INTERRUPT:
logger.info(
"[interrupt-debug] _wait_for_process TIMEOUT "
"tid=%s pid=%s iter=%d timeout=%ss",
_tid, _pid, _iter_count, timeout,
)
self._kill_process(proc)
drain_thread.join(timeout=2)
timeout_msg = f"\n[Command timed out after {timeout}s]"
return self._finalize_wait_result(
output,
output.render(suffix=timeout_msg).lstrip()
if output.total_chars == 0
else output.render(suffix=timeout_msg),
124,
)
# Periodic activity touch so the gateway knows we're alive
touch_activity_if_due(_activity_state, "terminal command running")
# Heartbeat every ~30s: proves the loop is alive and reports
# the activity-callback state (thread-local, can get clobbered
# by nested tool calls or executor thread reuse).
if _DEBUG_INTERRUPT and time.monotonic() - _last_heartbeat >= 30.0:
_cb_now_none = get_activity_callback() is None
logger.info(
"[interrupt-debug] _wait_for_process HEARTBEAT "
"tid=%s pid=%s iter=%d elapsed=%.0fs "
"interrupt=%s activity_cb=%s%s",
_tid, _pid, _iter_count,
time.monotonic() - _activity_state["start"],
is_interrupted(),
"set" if not _cb_now_none else "MISSING",
" (LOST during run)" if _cb_now_none and not _cb_was_none else "",
)
_last_heartbeat = time.monotonic()
_cb_was_none = _cb_now_none
# Adaptive poll: start at 5ms so fast commands (echo, pwd,
# date, cat short files) return in ~6ms instead of being
# stuck waiting for the next 200ms tick. Back off
# exponentially toward 200ms so long-running commands
# (builds, tests, sleeps) don't pay measurable CPU in the
# poll loop. For an `echo` this saves ~195ms per tool call;
# for a 10s build the steady-state poll rate is identical
# to the old behavior.
time.sleep(_poll_sleep)
if _poll_sleep < 0.2:
_poll_sleep = min(_poll_sleep * 1.5, 0.2)
except (KeyboardInterrupt, SystemExit):
# Signal arrived (SIGTERM/SIGHUP/SIGINT) or sys.exit() was called
# while we were polling. The local backend spawns subprocesses
# with os.setsid, which puts them in their own process group — so
# if we let the interrupt propagate without killing the child,
# python exits and the child is reparented to init (PPID=1) and
# keeps running as an orphan. Killing the process group here
# guarantees the tool's side effects stop when the agent stops.
if _DEBUG_INTERRUPT:
logger.info(
"[interrupt-debug] _wait_for_process EXCEPTION_EXIT "
"tid=%s pid=%s iter=%d elapsed=%.1fs — killing subprocess group before re-raise",
_tid, _pid, _iter_count,
time.monotonic() - _activity_state["start"],
)
try:
self._kill_process(proc)
drain_thread.join(timeout=2)
except Exception:
pass # cleanup is best-effort
raise
# Drain thread now exits promptly after bash does (~300ms idle
# check). A short join is enough; a long one would be a bug since
# it means the non-blocking loop itself stopped cooperating.
drain_thread.join(timeout=2)
try:
proc.stdout.close()
except Exception:
pass
if _DEBUG_INTERRUPT:
logger.info(
"[interrupt-debug] _wait_for_process EXIT (natural) "
"tid=%s pid=%s iter=%d elapsed=%.1fs returncode=%s",
_tid, _pid, _iter_count,
time.monotonic() - _activity_state["start"],
proc.returncode,
)
# Join the stdin writer thread before reading its error list: a child
# that exits without reading stdin can otherwise race ahead of a
# recorded encode failure, silently dropping it. The thread cannot
# block long after child exit (write raises BrokenPipeError once the
# pipe closes); the timeout is a pure safety net.
stdin_thread = getattr(proc, "_hermes_stdin_thread", None)
if stdin_thread is not None:
stdin_thread.join(timeout=5)
rendered = output.render()
result = self._finalize_wait_result(output, rendered, proc.returncode)
stdin_errors = getattr(proc, "_hermes_stdin_errors", None)
if stdin_errors:
err = str(stdin_errors[0])
result["stdin_error"] = err
result["output"] = rendered + f"\n[stdin write failed: {err}]"
return result
@staticmethod
def _finalize_wait_result(collector: "_BoundedOutputCollector",
rendered: str, returncode: int | None) -> dict:
"""Assemble a wait result, attaching spill metadata when overflow occurred."""
result = {"output": rendered, "returncode": returncode}
spill = collector.close_spill()
if spill:
result["output_total_chars"] = collector.total_chars
result["full_output_path"] = spill
return result
def _kill_process(self, proc: ProcessHandle):
"""Terminate a process. Subclasses may override for process-group kill."""
try:
proc.kill()
except (ProcessLookupError, PermissionError, OSError):
pass
# ------------------------------------------------------------------
# CWD extraction
# ------------------------------------------------------------------
def _update_cwd(self, result: dict):
"""Extract CWD from command output. Override for local file-based read."""
self._extract_cwd_from_output(result)
def _extract_cwd_from_output(self, result: dict):
"""Parse the __HERMES_CWD_{session}__ marker from stdout output.
Updates self.cwd and strips the marker from result["output"].
Used by remote backends (Docker, SSH, Modal, Daytona, Singularity).
Sets ``result["cwd_observed"]`` when the marker yielded a directory for
THIS command. The wrapper prints the marker after the command returns,
so a killed / timed-out command never emits one and ``self.cwd`` keeps
whatever the previous command left there. That environment is shared by
every session, so callers must not attribute an unobserved cwd to the
session that ran this command (see terminal_tool's session-cwd record).
"""
output = result.get("output", "")
marker = self._cwd_marker
last = output.rfind(marker)
if last == -1:
return
# Find the opening marker before this closing one
search_start = max(0, last - 4096) # CWD path won't be >4KB
first = output.rfind(marker, search_start, last)
if first == -1 or first == last:
return
cwd_path = output[first + len(marker) : last].strip()
if cwd_path:
self.cwd = cwd_path
result["cwd_observed"] = True
# Keep the observation on this command's result as well as on the
# shared environment. Concurrent callers must not read self.cwd
# after another command has already updated it.
result["cwd"] = cwd_path
# Strip the marker line AND the \n we injected before it.
# The wrapper emits: printf '\n__MARKER__%s__MARKER__\n'
# So the output looks like: <cmd output>\n__MARKER__path__MARKER__\n
# We want to remove everything from the injected \n onwards.
line_start = output.rfind("\n", 0, first)
if line_start == -1:
line_start = first
line_end = output.find("\n", last + len(marker))
line_end = line_end + 1 if line_end != -1 else len(output)
result["output"] = output[:line_start] + output[line_end:]
# ------------------------------------------------------------------
# Hooks
# ------------------------------------------------------------------
def _before_execute(self) -> None:
"""Hook called before each command execution.
Remote backends (SSH, Modal, Daytona) override this to trigger
their FileSyncManager. Bind-mount backends (Docker, Singularity)
and Local don't need file sync — the host filesystem is directly
visible inside the container/process.
"""
pass
# ------------------------------------------------------------------
# Unified execute()
# ------------------------------------------------------------------
def execute(
self,
command: str,
cwd: str = "",
*,
timeout: int | None = None,
stdin_data: str | None = None,
rewrite_compound_background: bool = True,
bounded_capture: bool = False,
) -> dict:
"""Execute a command, return {"output": str, "returncode": int}.
``bounded_capture=True`` caps stdout/stderr retention at
``tool_output.max_bytes`` WHILE the stream is drained (head/tail
window) instead of holding the full output in memory (#64435).
It must only be set by callers whose output is destined for the
model/tool payload (the foreground terminal tool). Internal
full-fidelity consumers — file operations ``cat`` reads that feed
the patch engine, code-execution RPC reads, log reads — MUST leave
it False: truncating those corrupts data, not just display.
The wait is bounded by ``agent.deadline.run_bounded_sync`` so a
wedged poll loop cannot hang past ``timeout`` and silently disable
every asyncio timer in the process (#94285).
"""
self._before_execute()
exec_command, sudo_stdin = self._prepare_command(command)
# Guard against the `A && B &` subshell-wait trap by default.
# Some callers (spawn_via_env) already produce shell-safe wrappers and
# pass rewrite_compound_background=False.
if rewrite_compound_background:
from tools.terminal_tool import _rewrite_compound_background
exec_command = _rewrite_compound_background(exec_command)
effective_timeout = timeout or self.timeout
effective_cwd = cwd or self.cwd
# Merge sudo stdin with caller stdin
if sudo_stdin is not None and stdin_data is not None:
effective_stdin = sudo_stdin + stdin_data
elif sudo_stdin is not None:
effective_stdin = sudo_stdin
else:
effective_stdin = stdin_data
# Embed stdin as heredoc for backends that need it
if effective_stdin and self._stdin_mode == "heredoc":
exec_command = self._embed_stdin_heredoc(exec_command, effective_stdin)
effective_stdin = None
wrapped = self._wrap_command(exec_command, effective_cwd)
# Use login shell if snapshot failed (so user's profile still loads),
# unless login itself is broken — then non-login is the only path.
login = not self._snapshot_ready and not self._prefer_nonlogin
parent_tid = threading.current_thread().ident
# Activity callback is thread-local (see set_activity_callback). The
# wait runs on the deadline worker, so copy it across or long
# commands look idle to cron/gateway heartbeats.
parent_activity_cb = get_activity_callback()
proc_holder: list = []
def _spawn_and_wait() -> dict:
if parent_activity_cb is not None:
set_activity_callback(parent_activity_cb)
spawned = self._run_bash(
wrapped, login=login, timeout=effective_timeout, stdin_data=effective_stdin
)
proc_holder.append(spawned)
return self._wait_for_process(
spawned,
timeout=effective_timeout,
bounded_capture=bounded_capture,
watch_interrupt_tid=parent_tid,
)
def _on_timeout() -> None:
if not proc_holder:
return
spawned = proc_holder[0]
try:
self._kill_process(spawned)
except Exception:
logger.debug(
"terminal wait-bound kill_process failed", exc_info=True
)
pid = getattr(spawned, "pid", None)
if not pid:
return
try:
from agent.deadline import kill_process_tree
kill_process_tree(int(pid))
except Exception:
logger.debug(
"terminal wait-bound kill_process_tree failed", exc_info=True
)
# Hard wall-clock backstop (#94285): ``_wait_for_process`` already
# polls to ``effective_timeout``, but that loop runs on the tool
# thread. If that thread is the event-loop thread — or the wait
# itself never returns (Windows pipe/poll hang) — every asyncio
# timer in the process is silently disabled, including the 420s
# sequential-tool deadline and the cron inactivity monitor.
# ``run_bounded_sync`` drives expiry from a daemon worker +
# ``Event.wait`` so a blocked loop cannot disable it. Grace lets
# the inner poll return the partial-output 124 path on a healthy
# timeout; the outer bound only fires when that loop is wedged.
from agent.deadline import run_bounded_sync
try:
bound_s = float(effective_timeout) + _EXECUTE_WAIT_BOUND_GRACE_S
except (TypeError, ValueError):
# Defensive: a non-numeric timeout must not silently disable the
# backstop (that would recreate the unbounded wait this bound
# exists to prevent). Fall back to the module's 120s wait default.
bound_s = 120.0 + _EXECUTE_WAIT_BOUND_GRACE_S
try:
bounded = run_bounded_sync(
_spawn_and_wait,
bound_s,
label=f"terminal.wait:{type(self).__name__}",
on_timeout=_on_timeout,
)
except (KeyboardInterrupt, SystemExit):
_on_timeout()
raise
if bounded.timed_out:
timeout_msg = f"\n[Command timed out after {effective_timeout}s]"
result = {"output": timeout_msg.lstrip(), "returncode": 124}
else:
result = bounded.value
self._update_cwd(result)
return result
# ------------------------------------------------------------------
# Shared helpers
# ------------------------------------------------------------------
def stop(self):
"""Alias for cleanup (compat with older callers)."""
self.cleanup()
def __del__(self):
try:
self.cleanup()
except Exception:
pass
def _prepare_command(self, command: str) -> tuple[str, str | None]:
"""Transform sudo commands if SUDO_PASSWORD is available."""
from tools.terminal_tool import _transform_sudo_command
return _transform_sudo_command(command)