Auto merge of #3929 - RalfJung:io-error, r=RalfJung

Make returning io errors more uniform and convenient

Author: bors

src/tools/miri/src/helpers.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeSet;
 use std::num::NonZero;
 use std::sync::Mutex;
 use std::time::Duration;
-use std::{cmp, io, iter};
+use std::{cmp, iter};
 
 use rand::RngCore;
 use rustc_apfloat::Float;
@@ -31,65 +31,6 @@ pub enum AccessKind {
     Write,
 }
 
-// This mapping should match `decode_error_kind` in
-// <https://github.com/rust-lang/rust/blob/master/library/std/src/sys/pal/unix/mod.rs>.
-const UNIX_IO_ERROR_TABLE: &[(&str, std::io::ErrorKind)] = {
-    use std::io::ErrorKind::*;
-    &[
-        ("E2BIG", ArgumentListTooLong),
-        ("EADDRINUSE", AddrInUse),
-        ("EADDRNOTAVAIL", AddrNotAvailable),
-        ("EBUSY", ResourceBusy),
-        ("ECONNABORTED", ConnectionAborted),
-        ("ECONNREFUSED", ConnectionRefused),
-        ("ECONNRESET", ConnectionReset),
-        ("EDEADLK", Deadlock),
-        ("EDQUOT", FilesystemQuotaExceeded),
-        ("EEXIST", AlreadyExists),
-        ("EFBIG", FileTooLarge),
-        ("EHOSTUNREACH", HostUnreachable),
-        ("EINTR", Interrupted),
-        ("EINVAL", InvalidInput),
-        ("EISDIR", IsADirectory),
-        ("ELOOP", FilesystemLoop),
-        ("ENOENT", NotFound),
-        ("ENOMEM", OutOfMemory),
-        ("ENOSPC", StorageFull),
-        ("ENOSYS", Unsupported),
-        ("EMLINK", TooManyLinks),
-        ("ENAMETOOLONG", InvalidFilename),
-        ("ENETDOWN", NetworkDown),
-        ("ENETUNREACH", NetworkUnreachable),
-        ("ENOTCONN", NotConnected),
-        ("ENOTDIR", NotADirectory),
-        ("ENOTEMPTY", DirectoryNotEmpty),
-        ("EPIPE", BrokenPipe),
-        ("EROFS", ReadOnlyFilesystem),
-        ("ESPIPE", NotSeekable),
-        ("ESTALE", StaleNetworkFileHandle),
-        ("ETIMEDOUT", TimedOut),
-        ("ETXTBSY", ExecutableFileBusy),
-        ("EXDEV", CrossesDevices),
-        // The following have two valid options. We have both for the forwards mapping; only the
-        // first one will be used for the backwards mapping.
-        ("EPERM", PermissionDenied),
-        ("EACCES", PermissionDenied),
-        ("EWOULDBLOCK", WouldBlock),
-        ("EAGAIN", WouldBlock),
-    ]
-};
-// This mapping should match `decode_error_kind` in
-// <https://github.com/rust-lang/rust/blob/master/library/std/src/sys/pal/windows/mod.rs>.
-const WINDOWS_IO_ERROR_TABLE: &[(&str, std::io::ErrorKind)] = {
-    use std::io::ErrorKind::*;
-    // FIXME: this is still incomplete.
-    &[
-        ("ERROR_ACCESS_DENIED", PermissionDenied),
-        ("ERROR_FILE_NOT_FOUND", NotFound),
-        ("ERROR_INVALID_PARAMETER", InvalidInput),
-    ]
-};
-
 /// Gets an instance for a path.
 ///
 /// A `None` namespace indicates we are looking for a module.
@@ -745,130 +686,6 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         self.eval_context_ref().tcx.sess.target.families.iter().any(|f| f == "unix")
     }
 
-    /// Get last error variable as a place, lazily allocating thread-local storage for it if
-    /// necessary.
-    fn last_error_place(&mut self) -> InterpResult<'tcx, MPlaceTy<'tcx>> {
-        let this = self.eval_context_mut();
-        if let Some(errno_place) = this.active_thread_ref().last_error.as_ref() {
-            Ok(errno_place.clone())
-        } else {
-            // Allocate new place, set initial value to 0.
-            let errno_layout = this.machine.layouts.u32;
-            let errno_place = this.allocate(errno_layout, MiriMemoryKind::Machine.into())?;
-            this.write_scalar(Scalar::from_u32(0), &errno_place)?;
-            this.active_thread_mut().last_error = Some(errno_place.clone());
-            Ok(errno_place)
-        }
-    }
-
-    /// Sets the last error variable.
-    fn set_last_error(&mut self, scalar: Scalar) -> InterpResult<'tcx> {
-        let this = self.eval_context_mut();
-        let errno_place = this.last_error_place()?;
-        this.write_scalar(scalar, &errno_place)
-    }
-
-    /// Gets the last error variable.
-    fn get_last_error(&mut self) -> InterpResult<'tcx, Scalar> {
-        let this = self.eval_context_mut();
-        let errno_place = this.last_error_place()?;
-        this.read_scalar(&errno_place)
-    }
-
-    /// This function tries to produce the most similar OS error from the `std::io::ErrorKind`
-    /// as a platform-specific errnum.
-    fn io_error_to_errnum(&self, err: std::io::Error) -> InterpResult<'tcx, Scalar> {
-        let this = self.eval_context_ref();
-        let target = &this.tcx.sess.target;
-        if target.families.iter().any(|f| f == "unix") {
-            for &(name, kind) in UNIX_IO_ERROR_TABLE {
-                if err.kind() == kind {
-                    return Ok(this.eval_libc(name));
-                }
-            }
-            throw_unsup_format!("unsupported io error: {err}")
-        } else if target.families.iter().any(|f| f == "windows") {
-            for &(name, kind) in WINDOWS_IO_ERROR_TABLE {
-                if err.kind() == kind {
-                    return Ok(this.eval_windows("c", name));
-                }
-            }
-            throw_unsup_format!("unsupported io error: {err}");
-        } else {
-            throw_unsup_format!(
-                "converting io::Error into errnum is unsupported for OS {}",
-                target.os
-            )
-        }
-    }
-
-    /// The inverse of `io_error_to_errnum`.
-    #[allow(clippy::needless_return)]
-    fn try_errnum_to_io_error(
-        &self,
-        errnum: Scalar,
-    ) -> InterpResult<'tcx, Option<std::io::ErrorKind>> {
-        let this = self.eval_context_ref();
-        let target = &this.tcx.sess.target;
-        if target.families.iter().any(|f| f == "unix") {
-            let errnum = errnum.to_i32()?;
-            for &(name, kind) in UNIX_IO_ERROR_TABLE {
-                if errnum == this.eval_libc_i32(name) {
-                    return Ok(Some(kind));
-                }
-            }
-            return Ok(None);
-        } else if target.families.iter().any(|f| f == "windows") {
-            let errnum = errnum.to_u32()?;
-            for &(name, kind) in WINDOWS_IO_ERROR_TABLE {
-                if errnum == this.eval_windows("c", name).to_u32()? {
-                    return Ok(Some(kind));
-                }
-            }
-            return Ok(None);
-        } else {
-            throw_unsup_format!(
-                "converting errnum into io::Error is unsupported for OS {}",
-                target.os
-            )
-        }
-    }
-
-    /// Sets the last OS error using a `std::io::ErrorKind`.
-    fn set_last_error_from_io_error(&mut self, err: std::io::Error) -> InterpResult<'tcx> {
-        self.set_last_error(self.io_error_to_errnum(err)?)
-    }
-
-    /// Sets the last OS error using a `std::io::ErrorKind` and writes -1 to dest place.
-    fn set_last_error_and_return(
-        &mut self,
-        err: impl Into<io::Error>,
-        dest: &MPlaceTy<'tcx>,
-    ) -> InterpResult<'tcx> {
-        self.set_last_error(self.io_error_to_errnum(err.into())?)?;
-        self.write_int(-1, dest)?;
-        Ok(())
-    }
-
-    /// Helper function that consumes an `std::io::Result<T>` and returns an
-    /// `InterpResult<'tcx,T>::Ok` instead. In case the result is an error, this function returns
-    /// `Ok(-1)` and sets the last OS error accordingly.
-    ///
-    /// This function uses `T: From<i32>` instead of `i32` directly because some IO related
-    /// functions return different integer types (like `read`, that returns an `i64`).
-    fn try_unwrap_io_result<T: From<i32>>(
-        &mut self,
-        result: std::io::Result<T>,
-    ) -> InterpResult<'tcx, T> {
-        match result {
-            Ok(ok) => Ok(ok),
-            Err(e) => {
-                self.eval_context_mut().set_last_error_from_io_error(e)?;
-                Ok((-1).into())
-            }
-        }
-    }
-
     /// Dereference a pointer operand to a place using `layout` instead of the pointer's declared type
     fn deref_pointer_as(
         &self,

src/tools/miri/src/lib.rs

@@ -150,6 +150,7 @@ pub use crate::range_map::RangeMap;
 pub use crate::shims::EmulateItemResult;
 pub use crate::shims::env::{EnvVars, EvalContextExt as _};
 pub use crate::shims::foreign_items::{DynSym, EvalContextExt as _};
+pub use crate::shims::io_error::{EvalContextExt as _, LibcError};
 pub use crate::shims::os_str::EvalContextExt as _;
 pub use crate::shims::panic::{CatchUnwindData, EvalContextExt as _};
 pub use crate::shims::time::EvalContextExt as _;