Rollup merge of #150723 - move_pal_error, r=@tgross35

std: move `errno` and related functions into `sys::io`

Part of #117276.

Currently, `errno` and related functions like `decode_error_kind` are split across `sys::pal` and `sys::pal::os`. This PR moves all of them into a new module inside `sys::io`.

Author: JonathanBrouwer

library/std/src/io/error.rs

@@ -653,7 +653,7 @@ impl Error {
     #[must_use]
     #[inline]
     pub fn last_os_error() -> Error {
-        Error::from_raw_os_error(sys::os::errno())
+        Error::from_raw_os_error(sys::io::errno())
     }
 
     /// Creates a new instance of an [`Error`] from a particular OS error code.
@@ -1004,7 +1004,7 @@ impl Error {
     #[inline]
     pub fn kind(&self) -> ErrorKind {
         match self.repr.data() {
-            ErrorData::Os(code) => sys::decode_error_kind(code),
+            ErrorData::Os(code) => sys::io::decode_error_kind(code),
             ErrorData::Custom(c) => c.kind,
             ErrorData::Simple(kind) => kind,
             ErrorData::SimpleMessage(m) => m.kind,
@@ -1014,7 +1014,7 @@ impl Error {
     #[inline]
     pub(crate) fn is_interrupted(&self) -> bool {
         match self.repr.data() {
-            ErrorData::Os(code) => sys::is_interrupted(code),
+            ErrorData::Os(code) => sys::io::is_interrupted(code),
             ErrorData::Custom(c) => c.kind == ErrorKind::Interrupted,
             ErrorData::Simple(kind) => kind == ErrorKind::Interrupted,
             ErrorData::SimpleMessage(m) => m.kind == ErrorKind::Interrupted,
@@ -1028,8 +1028,8 @@ impl fmt::Debug for Repr {
             ErrorData::Os(code) => fmt
                 .debug_struct("Os")
                 .field("code", &code)
-                .field("kind", &sys::decode_error_kind(code))
-                .field("message", &sys::os::error_string(code))
+                .field("kind", &sys::io::decode_error_kind(code))
+                .field("message", &sys::io::error_string(code))
                 .finish(),
             ErrorData::Custom(c) => fmt::Debug::fmt(&c, fmt),
             ErrorData::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
@@ -1047,7 +1047,7 @@ impl fmt::Display for Error {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.repr.data() {
             ErrorData::Os(code) => {
-                let detail = sys::os::error_string(code);
+                let detail = sys::io::error_string(code);
                 write!(fmt, "{detail} (os error {code})")
             }
             ErrorData::Custom(ref c) => c.error.fmt(fmt),

library/std/src/io/error/tests.rs

@@ -1,7 +1,6 @@
 use super::{Custom, Error, ErrorData, ErrorKind, Repr, SimpleMessage, const_error};
 use crate::assert_matches::assert_matches;
-use crate::sys::decode_error_kind;
-use crate::sys::os::error_string;
+use crate::sys::io::{decode_error_kind, error_string};
 use crate::{error, fmt};
 
 #[test]

library/std/src/sys/exit_guard.rs

@@ -34,7 +34,7 @@ cfg_select! {
             // lifetime of the thread. Additionally, accesses to `errno` are
             // async-signal-safe, so this function is available in all imaginable
             // circumstances.
-            let this_thread_id = crate::sys::os::errno_location();
+            let this_thread_id = crate::sys::io::errno_location();
             match EXITING_THREAD_ID.compare_exchange(ptr::null_mut(), this_thread_id, Acquire, Relaxed) {
                 Ok(_) => {
                     // This is the first thread to call `unique_thread_exit`,

library/std/src/sys/fs/unix.rs

@@ -850,7 +850,7 @@ impl Iterator for ReadDir {
         target_os = "wasi",
     ))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
-        use crate::sys::os::{errno, set_errno};
+        use crate::sys::io::{errno, set_errno};
 
         if self.end_of_stream {
             return None;
@@ -988,7 +988,7 @@ impl Iterator for ReadDir {
 /// The downside is that it costs an extra syscall, so we only do it for debug.
 #[inline]
 pub(crate) fn debug_assert_fd_is_open(fd: RawFd) {
-    use crate::sys::os::errno;
+    use crate::sys::io::errno;
 
     // this is similar to assert_unsafe_precondition!() but it doesn't require const
     if core::ub_checks::check_library_ub() {

library/std/src/sys/io/error/generic.rs

@@ -0,0 +1,15 @@
+pub fn errno() -> i32 {
+    0
+}
+
+pub fn is_interrupted(_code: i32) -> bool {
+    false
+}
+
+pub fn decode_error_kind(_code: i32) -> crate::io::ErrorKind {
+    crate::io::ErrorKind::Uncategorized
+}
+
+pub fn error_string(_errno: i32) -> String {
+    "operation successful".to_string()
+}

library/std/src/sys/io/error/hermit.rs

@@ -0,0 +1,35 @@
+use crate::io;
+
+pub fn errno() -> i32 {
+    unsafe { hermit_abi::get_errno() }
+}
+
+#[inline]
+pub fn is_interrupted(errno: i32) -> bool {
+    errno == hermit_abi::errno::EINTR
+}
+
+pub fn decode_error_kind(errno: i32) -> io::ErrorKind {
+    match errno {
+        hermit_abi::errno::EACCES => io::ErrorKind::PermissionDenied,
+        hermit_abi::errno::EADDRINUSE => io::ErrorKind::AddrInUse,
+        hermit_abi::errno::EADDRNOTAVAIL => io::ErrorKind::AddrNotAvailable,
+        hermit_abi::errno::EAGAIN => io::ErrorKind::WouldBlock,
+        hermit_abi::errno::ECONNABORTED => io::ErrorKind::ConnectionAborted,
+        hermit_abi::errno::ECONNREFUSED => io::ErrorKind::ConnectionRefused,
+        hermit_abi::errno::ECONNRESET => io::ErrorKind::ConnectionReset,
+        hermit_abi::errno::EEXIST => io::ErrorKind::AlreadyExists,
+        hermit_abi::errno::EINTR => io::ErrorKind::Interrupted,
+        hermit_abi::errno::EINVAL => io::ErrorKind::InvalidInput,
+        hermit_abi::errno::ENOENT => io::ErrorKind::NotFound,
+        hermit_abi::errno::ENOTCONN => io::ErrorKind::NotConnected,
+        hermit_abi::errno::EPERM => io::ErrorKind::PermissionDenied,
+        hermit_abi::errno::EPIPE => io::ErrorKind::BrokenPipe,
+        hermit_abi::errno::ETIMEDOUT => io::ErrorKind::TimedOut,
+        _ => io::ErrorKind::Uncategorized,
+    }
+}
+
+pub fn error_string(errno: i32) -> String {
+    hermit_abi::error_string(errno).to_string()
+}

library/std/src/sys/io/error/mod.rs

@@ -0,0 +1,55 @@
+cfg_select! {
+    target_os = "hermit" => {
+        mod hermit;
+        pub use hermit::*;
+    }
+    target_os = "motor" => {
+        mod motor;
+        pub use motor::*;
+    }
+    all(target_vendor = "fortanix", target_env = "sgx") => {
+        mod sgx;
+        pub use sgx::*;
+    }
+    target_os = "solid_asp3" => {
+        mod solid;
+        pub use solid::*;
+    }
+    target_os = "teeos" => {
+        mod teeos;
+        pub use teeos::*;
+    }
+    target_os = "uefi" => {
+        mod uefi;
+        pub use uefi::*;
+    }
+    target_family = "unix" => {
+        mod unix;
+        pub use unix::*;
+    }
+    target_os = "wasi" => {
+        mod wasi;
+        pub use wasi::*;
+    }
+    target_os = "windows" => {
+        mod windows;
+        pub use windows::*;
+    }
+    target_os = "xous" => {
+        mod xous;
+        pub use xous::*;
+    }
+    any(
+        target_os = "vexos",
+        target_family = "wasm",
+        target_os = "zkvm",
+    ) => {
+        mod generic;
+        pub use generic::*;
+    }
+}
+
+pub type RawOsError = cfg_select! {
+    target_os = "uefi" => usize,
+    _ => i32,
+};

library/std/src/sys/io/error/motor.rs

@@ -0,0 +1,67 @@
+use crate::io;
+use crate::sys::io::RawOsError;
+
+pub fn errno() -> RawOsError {
+    // Not used in Motor OS because it is ambiguous: Motor OS
+    // is micro-kernel-based, and I/O happens via a shared-memory
+    // ring buffer, so an I/O operation that on a unix is a syscall
+    // may involve no sycalls on Motor OS at all, or a syscall
+    // that e.g. waits for a notification from the I/O driver
+    // (sys-io); and the wait syscall may succeed, but the
+    // driver may report an I/O error; or a bunch of results
+    // for several I/O operations, some successful and some
+    // not.
+    //
+    // Also I/O operations in a Motor OS process are handled by a
+    // separate runtime background/I/O thread, so it is really hard
+    // to define what "last system error in the current thread"
+    // actually means.
+    let error_code: moto_rt::ErrorCode = moto_rt::Error::Unknown.into();
+    error_code.into()
+}
+
+pub fn is_interrupted(_code: io::RawOsError) -> bool {
+    false // Motor OS doesn't have signals.
+}
+
+pub fn decode_error_kind(code: io::RawOsError) -> io::ErrorKind {
+    if code < 0 || code > u16::MAX.into() {
+        return io::ErrorKind::Uncategorized;
+    }
+
+    let error = moto_rt::Error::from(code as moto_rt::ErrorCode);
+
+    match error {
+        moto_rt::Error::Unspecified => io::ErrorKind::Uncategorized,
+        moto_rt::Error::Unknown => io::ErrorKind::Uncategorized,
+        moto_rt::Error::NotReady => io::ErrorKind::WouldBlock,
+        moto_rt::Error::NotImplemented => io::ErrorKind::Unsupported,
+        moto_rt::Error::VersionTooHigh => io::ErrorKind::Unsupported,
+        moto_rt::Error::VersionTooLow => io::ErrorKind::Unsupported,
+        moto_rt::Error::InvalidArgument => io::ErrorKind::InvalidInput,
+        moto_rt::Error::OutOfMemory => io::ErrorKind::OutOfMemory,
+        moto_rt::Error::NotAllowed => io::ErrorKind::PermissionDenied,
+        moto_rt::Error::NotFound => io::ErrorKind::NotFound,
+        moto_rt::Error::InternalError => io::ErrorKind::Other,
+        moto_rt::Error::TimedOut => io::ErrorKind::TimedOut,
+        moto_rt::Error::AlreadyInUse => io::ErrorKind::AlreadyExists,
+        moto_rt::Error::UnexpectedEof => io::ErrorKind::UnexpectedEof,
+        moto_rt::Error::InvalidFilename => io::ErrorKind::InvalidFilename,
+        moto_rt::Error::NotADirectory => io::ErrorKind::NotADirectory,
+        moto_rt::Error::BadHandle => io::ErrorKind::InvalidInput,
+        moto_rt::Error::FileTooLarge => io::ErrorKind::FileTooLarge,
+        moto_rt::Error::NotConnected => io::ErrorKind::NotConnected,
+        moto_rt::Error::StorageFull => io::ErrorKind::StorageFull,
+        moto_rt::Error::InvalidData => io::ErrorKind::InvalidData,
+        _ => io::ErrorKind::Uncategorized,
+    }
+}
+
+pub fn error_string(errno: RawOsError) -> String {
+    let error: moto_rt::Error = match errno {
+        x if x < 0 => moto_rt::Error::Unknown,
+        x if x > u16::MAX.into() => moto_rt::Error::Unknown,
+        x => (x as moto_rt::ErrorCode).into(), /* u16 */
+    };
+    format!("{}", error)
+}

library/std/src/sys/io/error/sgx.rs

@@ -0,0 +1,65 @@
+use fortanix_sgx_abi::{Error, RESULT_SUCCESS};
+
+use crate::io;
+
+pub fn errno() -> i32 {
+    RESULT_SUCCESS
+}
+
+#[inline]
+pub fn is_interrupted(code: i32) -> bool {
+    code == fortanix_sgx_abi::Error::Interrupted as _
+}
+
+pub fn decode_error_kind(code: i32) -> io::ErrorKind {
+    // FIXME: not sure how to make sure all variants of Error are covered
+    if code == Error::NotFound as _ {
+        io::ErrorKind::NotFound
+    } else if code == Error::PermissionDenied as _ {
+        io::ErrorKind::PermissionDenied
+    } else if code == Error::ConnectionRefused as _ {
+        io::ErrorKind::ConnectionRefused
+    } else if code == Error::ConnectionReset as _ {
+        io::ErrorKind::ConnectionReset
+    } else if code == Error::ConnectionAborted as _ {
+        io::ErrorKind::ConnectionAborted
+    } else if code == Error::NotConnected as _ {
+        io::ErrorKind::NotConnected
+    } else if code == Error::AddrInUse as _ {
+        io::ErrorKind::AddrInUse
+    } else if code == Error::AddrNotAvailable as _ {
+        io::ErrorKind::AddrNotAvailable
+    } else if code == Error::BrokenPipe as _ {
+        io::ErrorKind::BrokenPipe
+    } else if code == Error::AlreadyExists as _ {
+        io::ErrorKind::AlreadyExists
+    } else if code == Error::WouldBlock as _ {
+        io::ErrorKind::WouldBlock
+    } else if code == Error::InvalidInput as _ {
+        io::ErrorKind::InvalidInput
+    } else if code == Error::InvalidData as _ {
+        io::ErrorKind::InvalidData
+    } else if code == Error::TimedOut as _ {
+        io::ErrorKind::TimedOut
+    } else if code == Error::WriteZero as _ {
+        io::ErrorKind::WriteZero
+    } else if code == Error::Interrupted as _ {
+        io::ErrorKind::Interrupted
+    } else if code == Error::Other as _ {
+        io::ErrorKind::Uncategorized
+    } else if code == Error::UnexpectedEof as _ {
+        io::ErrorKind::UnexpectedEof
+    } else {
+        io::ErrorKind::Uncategorized
+    }
+}
+
+pub fn error_string(errno: i32) -> String {
+    if errno == RESULT_SUCCESS {
+        "operation successful".into()
+    } else if ((Error::UserRangeStart as _)..=(Error::UserRangeEnd as _)).contains(&errno) {
+        format!("user-specified error {errno:08x}")
+    } else {
+        decode_error_kind(errno).as_str().into()
+    }
+}

library/std/src/sys/io/error/solid.rs

@@ -0,0 +1,19 @@
+use crate::io;
+use crate::sys::pal::error;
+
+pub fn errno() -> i32 {
+    0
+}
+
+#[inline]
+pub fn is_interrupted(code: i32) -> bool {
+    crate::sys::net::is_interrupted(code)
+}
+
+pub fn decode_error_kind(code: i32) -> io::ErrorKind {
+    error::decode_error_kind(code)
+}
+
+pub fn error_string(errno: i32) -> String {
+    if let Some(name) = error::error_name(errno) { name.to_owned() } else { format!("{errno}") }
+}