From 0fee0fd239845b1b5a798bb99c6240e20cd462e8 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Wed, 28 Feb 2024 09:46:58 +0100
Subject: [PATCH] add error number in thread local storage
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Keep a copy of the the error number in TLS

Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
---
 src/errno.rs  | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs    |  2 ++
 src/macros.rs | 52 ++++++++++++++++++++--------------
 3 files changed, 110 insertions(+), 21 deletions(-)

diff --git a/src/errno.rs b/src/errno.rs
index dc22dc8ced..07c68b64f7 100644
--- a/src/errno.rs
+++ b/src/errno.rs
@@ -395,3 +395,80 @@ pub const ERFKILL: i32 = 132;
 
 /// Robust mutexes: Memory page has hardware error
 pub const EHWPOISON: i32 = 133;
+
+#[cfg(all(not(feature = "common-os"), not(target_arch = "riscv64")))]
+#[thread_local]
+pub(crate) static ERRNO: core::cell::UnsafeCell<i32> = core::cell::UnsafeCell::new(0);
+
+/// Get the error number from the thread local storage
+#[no_mangle]
+pub extern "C" fn sys_get_errno() -> i32 {
+	cfg_if::cfg_if! {
+		if #[cfg(any(feature = "common-os", target_arch = "riscv64"))] {
+			0
+		} else {
+			unsafe { ERRNO.get().read() }
+		}
+	}
+}
+
+pub(crate) trait ToErrno {
+	fn to_errno(&self) -> Option<i32> {
+		None
+	}
+
+	fn set_errno(self) -> Self
+	where
+		Self: Sized,
+	{
+		if let Some(errno) = self.to_errno() {
+			cfg_if::cfg_if! {
+				if #[cfg(any(feature = "common-os", target_arch = "riscv64"))] {
+					let _ = errno;
+				} else {
+					unsafe {
+						ERRNO.get().write(errno);
+					}
+				}
+			}
+		}
+		self
+	}
+}
+
+impl ToErrno for i32 {
+	fn to_errno(&self) -> Option<i32> {
+		let errno = if *self < 0 { -self } else { 0 };
+		Some(errno)
+	}
+}
+
+impl ToErrno for i64 {
+	fn to_errno(&self) -> Option<i32> {
+		let errno = if *self < 0 {
+			i32::try_from(-self).unwrap()
+		} else {
+			0
+		};
+		Some(errno)
+	}
+}
+
+impl ToErrno for isize {
+	fn to_errno(&self) -> Option<i32> {
+		let errno = if *self < 0 {
+			i32::try_from(-self).unwrap()
+		} else {
+			0
+		};
+		Some(errno)
+	}
+}
+
+impl ToErrno for u8 {}
+impl ToErrno for u16 {}
+impl ToErrno for u32 {}
+impl ToErrno for usize {}
+impl ToErrno for *mut u8 {}
+impl ToErrno for () {}
+impl ToErrno for ! {}
diff --git a/src/lib.rs b/src/lib.rs
index 443e2b3a6e..d1ba286635 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,6 +18,7 @@
 #![feature(linked_list_cursors)]
 #![feature(maybe_uninit_slice)]
 #![feature(naked_functions)]
+#![feature(never_type)]
 #![feature(new_uninit)]
 #![feature(noop_waker)]
 #![feature(pointer_is_aligned)]
@@ -27,6 +28,7 @@
 	feature(specialization)
 )]
 #![feature(strict_provenance)]
+#![feature(thread_local)]
 #![cfg_attr(target_os = "none", no_std)]
 #![cfg_attr(target_os = "none", feature(custom_test_frameworks))]
 #![cfg_attr(all(target_os = "none", test), test_runner(crate::test_runner))]
diff --git a/src/macros.rs b/src/macros.rs
index 4dca430372..64a1b22d04 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -78,33 +78,41 @@ macro_rules! dbg {
 	feature = "common-os"
 )))]
 macro_rules! kernel_function {
-	($f:ident()) => {
-		$crate::arch::switch::kernel_function0($f)
-	};
+	($f:ident()) => {{
+		use $crate::errno::ToErrno;
+		$crate::arch::switch::kernel_function0($f).set_errno()
+	}};
 
-	($f:ident($arg1:expr)) => {
-		$crate::arch::switch::kernel_function1($f, $arg1)
-	};
+	($f:ident($arg1:expr)) => {{
+		use $crate::errno::ToErrno;
+		#[allow(unreachable_code)]
+		$crate::arch::switch::kernel_function1($f, $arg1).set_errno()
+	}};
 
-	($f:ident($arg1:expr, $arg2:expr)) => {
-		$crate::arch::switch::kernel_function2($f, $arg1, $arg2)
-	};
+	($f:ident($arg1:expr, $arg2:expr)) => {{
+		use $crate::errno::ToErrno;
+		$crate::arch::switch::kernel_function2($f, $arg1, $arg2).set_errno()
+	}};
 
-	($f:ident($arg1:expr, $arg2:expr, $arg3:expr)) => {
-		$crate::arch::switch::kernel_function3($f, $arg1, $arg2, $arg3)
-	};
+	($f:ident($arg1:expr, $arg2:expr, $arg3:expr)) => {{
+		use $crate::errno::ToErrno;
+		$crate::arch::switch::kernel_function3($f, $arg1, $arg2, $arg3).set_errno()
+	}};
 
-	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr)) => {
-		$crate::arch::switch::kernel_function4($f, $arg1, $arg2, $arg3, $arg4)
-	};
+	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr)) => {{
+		use $crate::errno::ToErrno;
+		$crate::arch::switch::kernel_function4($f, $arg1, $arg2, $arg3, $arg4).set_errno()
+	}};
 
-	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr, $arg5:expr)) => {
-		$crate::arch::switch::kernel_function5($f, $arg1, $arg2, $arg3, $arg4, $arg5)
-	};
+	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr, $arg5:expr)) => {{
+		$crate::arch::switch::kernel_function5($f, $arg1, $arg2, $arg3, $arg4, $arg5).set_errno()
+	}};
 
-	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr, $arg5:expr, $arg6:expr)) => {
+	($f:ident($arg1:expr, $arg2:expr, $arg3:expr, $arg4:expr, $arg5:expr, $arg6:expr)) => {{
+		use $crate::errno::ToErrno;
 		$crate::arch::switch::kernel_function6($f, $arg1, $arg2, $arg3, $arg4, $arg5, $arg6)
-	};
+			.set_errno()
+	}};
 }
 
 // TODO: Properly switch kernel stack with newlib
@@ -117,7 +125,9 @@ macro_rules! kernel_function {
 ))]
 macro_rules! kernel_function {
 	($f:ident($($x:tt)*)) => {{
-		$f($($x)*)
+		use $crate::errno::ToErrno;
+		#[allow(unreachable_code)]
+		$f($($x)*).set_errno()
 	}};
 }