/
timeout.rs
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/
timeout.rs
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// * This file is part of the uutils coreutils package.
// *
// * (c) Alex Lyon <arcterus@mail.com>
// *
// * For the full copyright and license information, please view the LICENSE
// * file that was distributed with this source code.
// spell-checker:ignore (ToDO) tstr sigstr cmdname setpgid sigchld getpid
mod status;
use crate::status::ExitStatus;
use clap::{crate_version, Arg, ArgAction, Command};
use std::io::ErrorKind;
use std::os::unix::process::ExitStatusExt;
use std::process::{self, Child, Stdio};
use std::time::Duration;
use uucore::display::Quotable;
use uucore::error::{UClapError, UResult, USimpleError, UUsageError};
use uucore::process::ChildExt;
use uucore::signals::{signal_by_name_or_value, signal_name_by_value};
use uucore::{format_usage, show_error};
static ABOUT: &str = "Start COMMAND, and kill it if still running after DURATION.";
const USAGE: &str = "{} [OPTION] DURATION COMMAND...";
pub mod options {
pub static FOREGROUND: &str = "foreground";
pub static KILL_AFTER: &str = "kill-after";
pub static SIGNAL: &str = "signal";
pub static PRESERVE_STATUS: &str = "preserve-status";
pub static VERBOSE: &str = "verbose";
// Positional args.
pub static DURATION: &str = "duration";
pub static COMMAND: &str = "command";
}
struct Config {
foreground: bool,
kill_after: Option<Duration>,
signal: usize,
duration: Duration,
preserve_status: bool,
verbose: bool,
command: Vec<String>,
}
impl Config {
fn from(options: &clap::ArgMatches) -> UResult<Self> {
let signal = match options.get_one::<String>(options::SIGNAL) {
Some(signal_) => {
let signal_result = signal_by_name_or_value(signal_);
match signal_result {
None => {
return Err(UUsageError::new(
ExitStatus::TimeoutFailed.into(),
format!("{}: invalid signal", signal_.quote()),
))
}
Some(signal_value) => signal_value,
}
}
_ => uucore::signals::signal_by_name_or_value("TERM").unwrap(),
};
let kill_after = match options.get_one::<String>(options::KILL_AFTER) {
None => None,
Some(kill_after) => match uucore::parse_time::from_str(kill_after) {
Ok(k) => Some(k),
Err(err) => return Err(UUsageError::new(ExitStatus::TimeoutFailed.into(), err)),
},
};
let duration = match uucore::parse_time::from_str(
options.get_one::<String>(options::DURATION).unwrap(),
) {
Ok(duration) => duration,
Err(err) => return Err(UUsageError::new(ExitStatus::TimeoutFailed.into(), err)),
};
let preserve_status: bool = options.get_flag(options::PRESERVE_STATUS);
let foreground = options.get_flag(options::FOREGROUND);
let verbose = options.get_flag(options::VERBOSE);
let command = options
.get_many::<String>(options::COMMAND)
.unwrap()
.map(String::from)
.collect::<Vec<_>>();
Ok(Self {
foreground,
kill_after,
signal,
duration,
preserve_status,
verbose,
command,
})
}
}
#[uucore::main]
pub fn uumain(args: impl uucore::Args) -> UResult<()> {
let args = args.collect_lossy();
let matches = uu_app().try_get_matches_from(args).with_exit_code(125)?;
let config = Config::from(&matches)?;
timeout(
&config.command,
config.duration,
config.signal,
config.kill_after,
config.foreground,
config.preserve_status,
config.verbose,
)
}
pub fn uu_app() -> Command {
Command::new("timeout")
.version(crate_version!())
.about(ABOUT)
.override_usage(format_usage(USAGE))
.arg(
Arg::new(options::FOREGROUND)
.long(options::FOREGROUND)
.help(
"when not running timeout directly from a shell prompt, allow \
COMMAND to read from the TTY and get TTY signals; in this mode, \
children of COMMAND will not be timed out",
)
.action(ArgAction::SetTrue),
)
.arg(
Arg::new(options::KILL_AFTER)
.long(options::KILL_AFTER)
.short('k')
.help(
"also send a KILL signal if COMMAND is still running this long \
after the initial signal was sent",
),
)
.arg(
Arg::new(options::PRESERVE_STATUS)
.long(options::PRESERVE_STATUS)
.help("exit with the same status as COMMAND, even when the command times out")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new(options::SIGNAL)
.short('s')
.long(options::SIGNAL)
.help(
"specify the signal to be sent on timeout; SIGNAL may be a name like \
'HUP' or a number; see 'kill -l' for a list of signals",
)
.value_name("SIGNAL"),
)
.arg(
Arg::new(options::VERBOSE)
.short('v')
.long(options::VERBOSE)
.help("diagnose to stderr any signal sent upon timeout")
.action(ArgAction::SetTrue),
)
.arg(Arg::new(options::DURATION).required(true))
.arg(
Arg::new(options::COMMAND)
.required(true)
.action(ArgAction::Append)
.value_hint(clap::ValueHint::CommandName),
)
.trailing_var_arg(true)
.infer_long_args(true)
}
/// Remove pre-existing SIGCHLD handlers that would make waiting for the child's exit code fail.
fn unblock_sigchld() {
unsafe {
nix::sys::signal::signal(
nix::sys::signal::Signal::SIGCHLD,
nix::sys::signal::SigHandler::SigDfl,
)
.unwrap();
}
}
/// Report that a signal is being sent if the verbose flag is set.
fn report_if_verbose(signal: usize, cmd: &str, verbose: bool) {
if verbose {
let s = signal_name_by_value(signal).unwrap();
show_error!("sending signal {} to command {}", s, cmd.quote());
}
}
fn send_signal(process: &mut Child, signal: usize, foreground: bool) {
// NOTE: GNU timeout doesn't check for errors of signal.
// The subprocess might have exited just after the timeout.
// Sending a signal now would return "No such process", but we should still try to kill the children.
_ = process.send_signal(signal);
if !foreground {
_ = process.send_signal_group(signal);
let kill_signal = signal_by_name_or_value("KILL").unwrap();
let continued_signal = signal_by_name_or_value("CONT").unwrap();
if signal != kill_signal && signal != continued_signal {
_ = process.send_signal(continued_signal);
_ = process.send_signal_group(continued_signal);
}
}
}
/// Wait for a child process and send a kill signal if it does not terminate.
///
/// This function waits for the child `process` for the time period
/// given by `duration`. If the child process does not terminate
/// within that time, we send the `SIGKILL` signal to it. If `verbose`
/// is `true`, then a message is printed to `stderr` when that
/// happens.
///
/// If the child process terminates within the given time period and
/// `preserve_status` is `true`, then the status code of the child
/// process is returned. If the child process terminates within the
/// given time period and `preserve_status` is `false`, then 124 is
/// returned. If the child does not terminate within the time period,
/// then 137 is returned. Finally, if there is an error while waiting
/// for the child process to terminate, then 124 is returned.
///
/// # Errors
///
/// If there is a problem sending the `SIGKILL` signal or waiting for
/// the process after that signal is sent.
fn wait_or_kill_process(
process: &mut Child,
cmd: &str,
duration: Duration,
preserve_status: bool,
foreground: bool,
verbose: bool,
) -> std::io::Result<i32> {
match process.wait_or_timeout(duration) {
Ok(Some(status)) => {
if preserve_status {
Ok(status.code().unwrap_or_else(|| status.signal().unwrap()))
} else {
Ok(ExitStatus::TimeoutFailed.into())
}
}
Ok(None) => {
let signal = signal_by_name_or_value("KILL").unwrap();
report_if_verbose(signal, cmd, verbose);
send_signal(process, signal, foreground);
process.wait()?;
Ok(ExitStatus::SignalSent(signal).into())
}
Err(_) => Ok(ExitStatus::WaitingFailed.into()),
}
}
#[cfg(unix)]
fn preserve_signal_info(signal: libc::c_int) -> libc::c_int {
// This is needed because timeout is expected to preserve the exit
// status of its child. It is not the case that utilities have a
// single simple exit code, that's an illusion some shells
// provide. Instead exit status is really two numbers:
//
// - An exit code if the program ran to completion
//
// - A signal number if the program was terminated by a signal
//
// The easiest way to preserve the latter seems to be to kill
// ourselves with whatever signal our child exited with, which is
// what the following is intended to accomplish.
unsafe {
libc::kill(libc::getpid(), signal);
}
signal
}
#[cfg(not(unix))]
fn preserve_signal_info(signal: libc::c_int) -> libc::c_int {
// Do nothing
signal
}
#[cfg(unix)]
fn enable_pipe_errors() -> std::io::Result<()> {
let ret = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_DFL) };
if ret == libc::SIG_ERR {
return Err(std::io::Error::new(std::io::ErrorKind::Other, ""));
}
Ok(())
}
#[cfg(not(unix))]
fn enable_pipe_errors() -> std::io::Result<()> {
// Do nothing.
Ok(())
}
/// TODO: Improve exit codes, and make them consistent with the GNU Coreutils exit codes.
fn timeout(
cmd: &[String],
duration: Duration,
signal: usize,
kill_after: Option<Duration>,
foreground: bool,
preserve_status: bool,
verbose: bool,
) -> UResult<()> {
if !foreground {
unsafe { libc::setpgid(0, 0) };
}
enable_pipe_errors()?;
let process = &mut process::Command::new(&cmd[0])
.args(&cmd[1..])
.stdin(Stdio::inherit())
.stdout(Stdio::inherit())
.stderr(Stdio::inherit())
.spawn()
.map_err(|err| {
let status_code = if err.kind() == ErrorKind::NotFound {
// FIXME: not sure which to use
127
} else {
// FIXME: this may not be 100% correct...
126
};
USimpleError::new(status_code, format!("failed to execute process: {err}"))
})?;
unblock_sigchld();
// Wait for the child process for the specified time period.
//
// If the process exits within the specified time period (the
// `Ok(Some(_))` arm), then return the appropriate status code.
//
// If the process does not exit within that time (the `Ok(None)`
// arm) and `kill_after` is specified, then try sending `SIGKILL`.
//
// TODO The structure of this block is extremely similar to the
// structure of `wait_or_kill_process()`. They can probably be
// refactored into some common function.
match process.wait_or_timeout(duration) {
Ok(Some(status)) => Err(status
.code()
.unwrap_or_else(|| preserve_signal_info(status.signal().unwrap()))
.into()),
Ok(None) => {
report_if_verbose(signal, &cmd[0], verbose);
send_signal(process, signal, foreground);
match kill_after {
None => {
if preserve_status {
Err(ExitStatus::SignalSent(signal).into())
} else {
Err(ExitStatus::CommandTimedOut.into())
}
}
Some(kill_after) => {
match wait_or_kill_process(
process,
&cmd[0],
kill_after,
preserve_status,
foreground,
verbose,
) {
Ok(status) => Err(status.into()),
Err(e) => Err(USimpleError::new(
ExitStatus::TimeoutFailed.into(),
format!("{e}"),
)),
}
}
}
}
Err(_) => {
// We're going to return ERR_EXIT_STATUS regardless of
// whether `send_signal()` succeeds or fails
send_signal(process, signal, foreground);
Err(ExitStatus::TimeoutFailed.into())
}
}
}