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fix: wrap commands in /bin/sh -c for proper server-side argv expansion

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The server-side agent runs commands through a nice wrapper that uses
"${@}" expansion. Sending the full command string as a single cmd field
caused nice to treat it as one executable name. Now Commands.run sends
cmd=/bin/sh args=["-c", cmd_string] so "${@}" expands into proper argv.
This commit is contained in:
Rafeed M. Bhuiyan
2026-04-23 05:16:08 +06:00
parent 6bdf28e2ae
commit ee1f55635f
2 changed files with 175 additions and 6 deletions
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26
src/wrenn/commands.py
View File

@ -183,7 +183,11 @@ class Commands:
CommandHandle: PID and tag for background commands
(``background=True``).
"""
payload: dict = {"cmd": cmd, "background": background}
payload: dict = {
"cmd": "/bin/sh",
"args": ["-c", cmd],
"background": background,
}
if timeout is not None and not background:
payload["timeout_sec"] = timeout
if envs is not None:
@ -271,6 +275,8 @@ class Commands:
Args:
cmd (str): Command to execute.
args (list[str] | None): Additional arguments for the command.
When omitted, *cmd* is interpreted as a shell command
string and executed via ``/bin/sh -c``.
Yields:
StreamEvent: Successive events including :class:`StreamStartEvent`,
@ -281,9 +287,10 @@ class Commands:
f"/v1/capsules/{self._capsule_id}/exec/stream",
self._http,
) as ws:
start_msg: dict = {"type": "start", "cmd": cmd}
if args:
start_msg["args"] = args
start_msg: dict = {"type": "start", "cmd": cmd, "args": args}
else:
start_msg = {"type": "start", "cmd": "/bin/sh", "args": ["-c", cmd]}
ws.send_text(json.dumps(start_msg))
while True:
try:
@ -359,7 +366,11 @@ class AsyncCommands:
CommandHandle: PID and tag for background commands
(``background=True``).
"""
payload: dict = {"cmd": cmd, "background": background}
payload: dict = {
"cmd": "/bin/sh",
"args": ["-c", cmd],
"background": background,
}
if timeout is not None and not background:
payload["timeout_sec"] = timeout
if envs is not None:
@ -449,6 +460,8 @@ class AsyncCommands:
Args:
cmd (str): Command to execute.
args (list[str] | None): Additional arguments for the command.
When omitted, *cmd* is interpreted as a shell command
string and executed via ``/bin/sh -c``.
Yields:
StreamEvent: Successive events including :class:`StreamStartEvent`,
@ -459,9 +472,10 @@ class AsyncCommands:
f"/v1/capsules/{self._capsule_id}/exec/stream",
self._http,
) as ws:
start_msg: dict = {"type": "start", "cmd": cmd}
if args:
start_msg["args"] = args
start_msg: dict = {"type": "start", "cmd": cmd, "args": args}
else:
start_msg = {"type": "start", "cmd": "/bin/sh", "args": ["-c", cmd]}
await ws.send_text(json.dumps(start_msg))
try:
while True:

155
tests/test_git.py
View File

@ -1,5 +1,7 @@
from __future__ import annotations
import json
import pytest
import respx
from httpx import Response
@ -942,3 +944,156 @@ class TestAsyncGit:
git = _make_async_git()
branches = await git.branches(cwd="/repo")
assert len(branches) == 2
# ════════════════════════════════<E29590><E29590>═════════════════════════════════
# Command payload tests — verify /bin/sh -c wrapping
# ════════════════════════════<E29590><E29590><EFBFBD>══════════════════════<E29590><E29590><EFBFBD>══════════════
class TestCommandPayloadWrapping:
"""Verify that Commands.run sends cmd=/bin/sh args=['-c', cmd_string]
so the server-side wrapper expands "${@}" into proper argv."""
@respx.mock
def test_simple_command(self):
route = respx.post(EXEC_URL).respond(200, json=_exec_response(
stdout="hello world\n"
))
git = _make_git()
git.init("/repo")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", git_cmd_from_body(body)]
# args[1] should contain the actual git command
assert body["args"][0] == "-c"
assert "git" in body["args"][1]
@respx.mock
def test_command_with_pipes(self):
"""Pipes and redirects work because /bin/sh interprets them."""
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response(
stdout="3\n"
))
commands.run("cat /etc/passwd | wc -l")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "cat /etc/passwd | wc -l"]
@respx.mock
def test_command_with_semicolons(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
commands.run("cd /tmp; ls -la && echo done")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "cd /tmp; ls -la && echo done"]
@respx.mock
def test_command_with_env_vars(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
commands.run("FOO=bar echo $FOO")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "FOO=bar echo $FOO"]
@respx.mock
def test_command_with_subshell(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
commands.run("echo $(date +%s)")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "echo $(date +%s)"]
@respx.mock
def test_command_with_quotes_and_spaces(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
commands.run("""echo "hello 'world'" | grep -o "'[^']*'" """)
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"][0] == "-c"
# The command string is passed verbatim — shell interprets it
assert "hello 'world'" in body["args"][1]
@respx.mock
def test_heredoc_style_command(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
commands.run("python3 -c 'import sys; print(sys.version)'")
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "python3 -c 'import sys; print(sys.version)'"]
@respx.mock
def test_git_shlex_joined_command(self):
"""Git module uses shlex.join — verify it passes through correctly."""
route = respx.post(EXEC_URL).respond(200, json=_exec_response())
git = _make_git()
git.clone("https://github.com/user/repo.git", "/tmp/repo", depth=1)
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"][0] == "-c"
# shlex.join produces: git clone --depth 1 https://... /tmp/repo
shell_cmd = body["args"][1]
assert "git" in shell_cmd
assert "clone" in shell_cmd
assert "--depth" in shell_cmd
assert "https://github.com/user/repo.git" in shell_cmd
@respx.mock
def test_background_command_also_wrapped(self):
from wrenn.client import WrennClient
from wrenn.commands import Commands
client = WrennClient(api_key="wrn_test1234567890abcdef12345678")
commands = Commands(CAPSULE_ID, client.http)
route = respx.post(EXEC_URL).respond(200, json={
"pid": 42, "tag": "bg-1"
})
commands.run("tail -f /var/log/syslog", background=True)
body = json.loads(route.calls[0].request.content)
assert body["cmd"] == "/bin/sh"
assert body["args"] == ["-c", "tail -f /var/log/syslog"]
assert body["background"] is True
def git_cmd_from_body(body: dict) -> str:
"""Extract the shell command string from a wrapped payload."""
assert body["cmd"] == "/bin/sh"
assert body["args"][0] == "-c"
return body["args"][1]