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Merge pull request #4271 from eds-collabora/eds/nice

Support legacy argument syntax for nice
This commit is contained in:
Sylvestre Ledru 2023-01-22 20:57:08 +01:00 committed by GitHub
commit 6f95f0953b
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2 changed files with 120 additions and 5 deletions

View file

@ -8,14 +8,14 @@
// spell-checker:ignore (ToDO) getpriority execvp setpriority nstr PRIO cstrs ENOENT
use libc::{c_char, c_int, execvp, PRIO_PROCESS};
use std::ffi::CString;
use std::io::Error;
use std::ffi::{CString, OsString};
use std::io::{Error, Write};
use std::ptr;
use clap::{crate_version, Arg, ArgAction, Command};
use uucore::{
error::{set_exit_code, UClapError, UResult, USimpleError, UUsageError},
format_usage, show_error, show_warning,
format_usage, show_error,
};
pub mod options {
@ -30,8 +30,89 @@ const ABOUT: &str = "\
process).";
const USAGE: &str = "{} [OPTIONS] [COMMAND [ARGS]]";
fn is_prefix_of(maybe_prefix: &str, target: &str, min_match: usize) -> bool {
if maybe_prefix.len() < min_match || maybe_prefix.len() > target.len() {
return false;
}
&target[0..maybe_prefix.len()] == maybe_prefix
}
/// Transform legacy arguments into a standardized form.
///
/// The following are all legal argument sequences to GNU nice:
/// - "-1"
/// - "-n1"
/// - "-+1"
/// - "--1"
/// - "-n -1"
///
/// It looks initially like we could add handling for "-{i}", "--{i}"
/// and "-+{i}" for integers {i} and process them normally using clap.
/// However, the meaning of "-1", for example, changes depending on
/// its context with legacy argument parsing. clap will not prioritize
/// hyphenated values to previous arguments over matching a known
/// argument. So "-n" "-1" in this case is picked up as two
/// arguments, not one argument with a value.
///
/// Given this context dependency, and the deep hole we end up digging
/// with clap in this case, it's much simpler to just normalize the
/// arguments to nice before clap starts work. Here, we insert a
/// prefix of "-n" onto all arguments of the form "-{i}", "--{i}" and
/// "-+{i}" which are not already preceded by "-n".
fn standardize_nice_args(mut args: impl uucore::Args) -> impl uucore::Args {
let mut v = Vec::<OsString>::new();
let mut saw_n = false;
let mut saw_command = false;
if let Some(cmd) = args.next() {
v.push(cmd);
}
for s in args {
if saw_command {
v.push(s);
} else if saw_n {
let mut new_arg: OsString = "-n".into();
new_arg.push(s);
v.push(new_arg);
saw_n = false;
} else if s.to_str() == Some("-n")
|| s.to_str()
.map(|s| is_prefix_of(s, "--adjustment", "--a".len()))
.unwrap_or_default()
{
saw_n = true;
} else if let Ok(s) = s.clone().into_string() {
if let Some(stripped) = s.strip_prefix('-') {
match stripped.parse::<i64>() {
Ok(ix) => {
let mut new_arg: OsString = "-n".into();
new_arg.push(ix.to_string());
v.push(new_arg);
}
Err(_) => {
v.push(s.into());
}
}
} else {
saw_command = true;
v.push(s.into());
}
} else {
saw_command = true;
v.push(s);
}
}
if saw_n {
v.push("-n".into());
}
v.into_iter()
}
#[uucore::main]
pub fn uumain(args: impl uucore::Args) -> UResult<()> {
let args = standardize_nice_args(args);
let matches = uu_app().try_get_matches_from(args).with_exit_code(125)?;
nix::errno::Errno::clear();
@ -71,8 +152,21 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
};
niceness += adjustment;
if unsafe { libc::setpriority(PRIO_PROCESS, 0, niceness) } == -1 {
show_warning!("setpriority: {}", Error::last_os_error());
// We can't use `show_warning` because that will panic if stderr
// isn't writable. The GNU test suite checks specifically that the
// exit code when failing to write the advisory is 125, but Rust
// will produce an exit code of 101 when it panics.
if unsafe { libc::setpriority(PRIO_PROCESS, 0, niceness) } == -1
&& write!(
std::io::stderr(),
"{}: warning: setpriority: {}",
uucore::util_name(),
Error::last_os_error()
)
.is_err()
{
set_exit_code(125);
return Ok(());
}
let cstrs: Vec<CString> = matches
@ -109,6 +203,8 @@ pub fn uu_app() -> Command {
.short('n')
.long(options::ADJUSTMENT)
.help("add N to the niceness (default is 10)")
.action(ArgAction::Set)
.overrides_with(options::ADJUSTMENT)
.allow_hyphen_values(true),
)
.arg(

View file

@ -63,3 +63,22 @@ fn test_command_where_command_takes_n_flag() {
fn test_invalid_argument() {
new_ucmd!().arg("--invalid").fails().code_is(125);
}
#[test]
fn test_bare_adjustment() {
new_ucmd!()
.args(&["-1", "echo", "-n", "a"])
.run()
.stdout_is("a");
}
#[test]
fn test_trailing_empty_adjustment() {
new_ucmd!()
.args(&["-n", "1", "-n"])
.fails()
.stderr_str()
.starts_with(
"error: The argument '--adjustment <adjustment>' requires a value but none was supplied",
);
}