//! Implementation of `errno` functionality for Unix systems.

//!

//! Adapted from `src/libstd/sys/unix/os.rs` in the Rust distribution.

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT

// file at the top-level directory of this distribution and at

// http://rust-lang.org/COPYRIGHT.

//

// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or

// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license

// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your

// option. This file may not be copied, modified, or distributed

// except according to those terms.

use core::str;

use libc::{self, c_int, size_t, strerror_r, strlen};

use crate::Errno;

fn from_utf8_lossy(input: &[u8]) -> &str {

    match str::from_utf8(input) {

        Ok(valid) => valid,

        Err(error) => unsafe { str::from_utf8_unchecked(&input[..error.valid_up_to()]) },

    }

}

pub fn with_description<F, T>(err: Errno, callback: F) -> T

where

    F: FnOnce(Result<&str, Errno>) -> T,

{

    let mut buf = [0u8; 1024];

    let c_str = unsafe {

        let rc = strerror_r(err.0, buf.as_mut_ptr() as *mut _, buf.len() as size_t);

        if rc != 0 {

            // Handle negative return codes for compatibility with glibc < 2.13

            let fm_err = match rc < 0 {

                true => errno(),

                false => Errno(rc),

            };

            if fm_err != Errno(libc::ERANGE) {

                return callback(Err(fm_err));

            }

        }

        let c_str_len = strlen(buf.as_ptr() as *const _);

        &buf[..c_str_len]

    };

    callback(Ok(from_utf8_lossy(c_str)))

}

Unexecuted instantiation: errno::sys::with_description::<<errno::Errno as core::fmt::Debug>::fmt::{closure#0}, core::result::Result<(), core::fmt::Error>>

Unexecuted instantiation: errno::sys::with_description::<<errno::Errno as core::fmt::Display>::fmt::{closure#0}, core::result::Result<(), core::fmt::Error>>

pub const STRERROR_NAME: &str = "strerror_r";

pub fn errno() -> Errno {

    unsafe { Errno(*errno_location()) }

}

pub fn set_errno(Errno(errno): Errno) {

    unsafe {

        *errno_location() = errno;

    }

}

extern "C" {

    #[cfg_attr(

        any(

            target_os = "macos",

            target_os = "ios",

            target_os = "tvos",

            target_os = "watchos",

            target_os = "visionos",

            target_os = "freebsd"

        ),

        link_name = "__error"

    )]

    #[cfg_attr(

        any(

            target_os = "openbsd",

            target_os = "netbsd",

            target_os = "android",

            target_os = "espidf",

            target_os = "vxworks",

            target_os = "cygwin",

            target_env = "newlib"

        ),

        link_name = "__errno"

    )]

    #[cfg_attr(

        any(target_os = "solaris", target_os = "illumos"),

        link_name = "___errno"

    )]

    #[cfg_attr(target_os = "haiku", link_name = "_errnop")]

    #[cfg_attr(

        any(

            target_os = "linux",

            target_os = "hurd",

            target_os = "redox",

            target_os = "dragonfly",

            target_os = "emscripten",

        ),

        link_name = "__errno_location"

    )]

    #[cfg_attr(target_os = "aix", link_name = "_Errno")]

    #[cfg_attr(target_os = "nto", link_name = "__get_errno_ptr")]

    fn errno_location() -> *mut c_int;

}