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// * This file is part of the uutils coreutils package.
// *
// * (c) Derek Chiang <derekchiang93@gmail.com>
// *
// * For the full copyright and license information, please view the LICENSE
// * file that was distributed with this source code.
use clap::ArgAction;
use clap::{crate_version, Arg, Command};
use std::env;
use std::io;
use std::path::PathBuf;
use uucore::{format_usage, help_about, help_usage};
use uucore::display::println_verbatim;
use uucore::error::{FromIo, UResult};
const ABOUT: &str = help_about!("pwd.md");
const USAGE: &str = help_usage!("pwd.md");
const OPT_LOGICAL: &str = "logical";
const OPT_PHYSICAL: &str = "physical";
fn physical_path() -> io::Result<PathBuf> {
// std::env::current_dir() is a thin wrapper around libc::getcwd().
// On Unix, getcwd() must return the physical path:
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/getcwd.html
#[cfg(unix)]
{
env::current_dir()
}
// On Windows we have to resolve it.
// On other systems we also resolve it, just in case.
#[cfg(not(unix))]
{
env::current_dir().and_then(|path| path.canonicalize())
}
}
fn logical_path() -> io::Result<PathBuf> {
// getcwd() on Windows seems to include symlinks, so this is easy.
#[cfg(windows)]
{
env::current_dir()
}
// If we're not on Windows we do things Unix-style.
//
// Typical Unix-like kernels don't actually keep track of the logical working
// directory. They know the precise directory a process is in, and the getcwd()
// syscall reconstructs a path from that.
//
// The logical working directory is maintained by the shell, in the $PWD
// environment variable. So we check carefully if that variable looks
// reasonable, and if not then we fall back to the physical path.
//
// POSIX: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pwd.html
#[cfg(not(windows))]
{
use std::path::Path;
fn looks_reasonable(path: &Path) -> bool {
// First, check if it's an absolute path.
if !path.has_root() {
return false;
}
// Then, make sure there are no . or .. components.
// Path::components() isn't useful here, it normalizes those out.
// to_string_lossy() may allocate, but that's fine, we call this
// only once per run. It may also lose information, but not any
// information that we need for this check.
if path
.to_string_lossy()
.split(std::path::is_separator)
.any(|piece| piece == "." || piece == "..")
{
return false;
}
// Finally, check if it matches the directory we're in.
#[cfg(unix)]
{
use std::fs::metadata;
use std::os::unix::fs::MetadataExt;
match (metadata(path), metadata(".")) {
(Ok(info1), Ok(info2)) => {
info1.dev() == info2.dev() && info1.ino() == info2.ino()
}
_ => false,
}
}
#[cfg(not(unix))]
{
use std::fs::canonicalize;
match (canonicalize(path), canonicalize(".")) {
(Ok(path1), Ok(path2)) => path1 == path2,
_ => false,
}
}
}
match env::var_os("PWD").map(PathBuf::from) {
Some(value) if looks_reasonable(&value) => Ok(value),
_ => env::current_dir(),
}
}
}
#[uucore::main]
pub fn uumain(args: impl uucore::Args) -> UResult<()> {
let matches = uu_app().try_get_matches_from(args)?;
// if POSIXLY_CORRECT is set, we want to a logical resolution.
// This produces a different output when doing mkdir -p a/b && ln -s a/b c && cd c && pwd
// We should get c in this case instead of a/b at the end of the path
let cwd = if matches.get_flag(OPT_LOGICAL) || env::var("POSIXLY_CORRECT").is_ok() {
logical_path()
} else {
physical_path()
}
.map_err_context(|| "failed to get current directory".to_owned())?;
// \\?\ is a prefix Windows gives to paths under certain circumstances,
// including when canonicalizing them.
// With the right extension trait we can remove it non-lossily, but
// we print it lossily anyway, so no reason to bother.
#[cfg(windows)]
let cwd = cwd
.to_string_lossy()
.strip_prefix(r"\\?\")
.map(Into::into)
.unwrap_or(cwd);
println_verbatim(cwd).map_err_context(|| "failed to print current directory".to_owned())?;
Ok(())
}
pub fn uu_app() -> Command {
Command::new(uucore::util_name())
.version(crate_version!())
.about(ABOUT)
.override_usage(format_usage(USAGE))
.infer_long_args(true)
.arg(
Arg::new(OPT_LOGICAL)
.short('L')
.long(OPT_LOGICAL)
.help("use PWD from environment, even if it contains symlinks")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new(OPT_PHYSICAL)
.short('P')
.long(OPT_PHYSICAL)
.overrides_with(OPT_LOGICAL)
.help("avoid all symlinks")
.action(ArgAction::SetTrue),
)
}
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