1 files changed, 101 insertions, 0 deletions
diff --git a/src/unix.rs b/src/unix.rs
new file mode 100644
index 0000000..18951e4
--- /dev/null
+++ b/src/unix.rs
@@ -0,0 +1,101 @@
+//! 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)))
+}
+
+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 = "freebsd"
+        ),
+        link_name = "__error"
+    )]
+    #[cfg_attr(
+        any(
+            target_os = "openbsd",
+            target_os = "netbsd",
+            target_os = "bitrig",
+            target_os = "android",
+            target_os = "espidf",
+            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"
+        ),
+        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;
+}