IO, error handling

safe_libc/src/boxed.rs

@@ -11,7 +11,7 @@ fn alloc<T>(len: usize) -> *mut T {
 	let align = mem::align_of::<T>();
 	util::must_succeed(
 		unsafe {
-			libc::memalign(align as libc::size_t, size as libc::size_t)
+			libc::memalign(align, size)
 		}
 	).cast()
 }

safe_libc/src/errno.rs

@@ -0,0 +1,29 @@
+use crate::string;
+
+use core::fmt;
+
+#[derive(Clone, Copy, Debug)]
+#[repr(transparent)]
+pub struct Errno(pub libc::c_int);
+
+#[inline]
+pub fn errno() -> Errno {
+	unsafe { Errno(*libc::__errno_location()) }
+}
+
+impl fmt::Display for Errno {
+	#[inline]
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		let mut buf = [0u8; 1024];
+		let cstr = unsafe {
+			if libc::strerror_r(self.0, buf.as_mut_ptr().cast(), buf.len()) != 0 {
+				return Err(fmt::Error);
+			}
+			string::CStr::from_bytes_with_nul_unchecked(&buf)
+		};
+		match cstr.to_str() {
+			Err(_) => Err(fmt::Error),
+			Ok(s) => f.write_str(s),
+		}
+	}
+}

safe_libc/src/lib.rs

@@ -5,6 +5,7 @@ pub use libc::*;
 mod util;
 
 pub mod boxed;
+pub mod errno;
 pub mod stdio;
 pub mod string;
 

safe_libc/src/stdio.rs

@@ -1,47 +1,111 @@
-use crate as libc;
-use crate::string;
+use crate::{self as libc, errno, string};
 
 use core::fmt;
+use core::ops::{Deref, DerefMut};
 
-pub struct OStream {
-	file: *mut libc::FILE
+pub struct Error {
+	pub errno: errno::Errno,
+}
+
+pub type Result<T> = core::result::Result<T, Error>;
+
+#[inline]
+fn check_io(ok: bool) -> Result<()> {
+	if ok {
+		Ok(())
+	} else {
+		Err(Error {
+			errno: errno::errno(),
+		})
+	}
+}
+
+pub struct BasicOStream(*mut libc::FILE);
+
+unsafe impl Sync for BasicOStream {}
+unsafe impl Send for BasicOStream {}
+
+pub type Stdout = BasicOStream;
+pub type Stderr = BasicOStream;
+
+#[inline]
+pub fn stdout() -> Stdout {
+	BasicOStream(unsafe { libc::stdout })
 }
 
 #[inline]
-pub unsafe fn stdout() -> OStream {
-	OStream { file: libc::stdout }
+pub fn stderr() -> Stderr {
+	BasicOStream(unsafe { libc::stderr })
+}
+
+impl BasicOStream {
+	#[inline]
+	pub fn flush(&mut self) -> Result<()> {
+		check_io(unsafe {
+			libc::fflush(self.0)
+		} == 0)
 	}
 
 	#[inline]
-pub unsafe fn stderr() -> OStream {
-	OStream { file: libc::stderr }
-}
-
-impl OStream {
-	#[inline]
-	pub fn write(&mut self, b: &[u8]) {
-		unsafe {
+	pub fn write(&mut self, b: &[u8]) -> Result<()> {
+		check_io(unsafe {
 			libc::fwrite(
 				b.as_ptr().cast(),
 				1,
 				b.len(),
-				self.file,
-			);
-		}
+				self.0,
+			)
+		} == b.len())
 	}
 
 	#[inline]
-	pub fn puts(&mut self, s: &string::CStr) {
-		unsafe {
-			libc::fputs(s.as_ptr(), self.file);
-		}
+	pub fn puts(&mut self, s: &string::CStr) -> Result<()> {
+		check_io(unsafe {
+			libc::fputs(s.as_ptr(), self.0)
+		} != libc::EOF)
 	}
 }
 
-impl fmt::Write for OStream {
+impl fmt::Write for BasicOStream {
 	#[inline]
 	fn write_str(&mut self, s: &str) -> fmt::Result {
-		self.write(s.as_bytes());
+		if self.write(s.as_bytes()).is_err() {
+			return Err(fmt::Error);
+		}
 		Ok(())
 	}
 }
+
+pub struct OStream(BasicOStream);
+
+impl OStream {
+	#[inline]
+	pub unsafe fn from_raw(file: *mut libc::FILE) -> OStream {
+		OStream(BasicOStream(file))
+	}
+}
+
+impl Drop for OStream {
+	#[inline]
+	fn drop(&mut self) {
+		unsafe {
+			libc::fclose((self.0).0);
+		}
+	}
+}
+
+impl Deref for OStream {
+	type Target = BasicOStream;
+
+	#[inline]
+	fn deref(&self) -> &BasicOStream {
+		&self.0
+	}
+}
+
+impl DerefMut for OStream {
+	#[inline]
+	fn deref_mut(&mut self) -> &mut BasicOStream {
+		&mut self.0
+	}
+}

safe_libc/src/string.rs

@@ -1,12 +1,11 @@
-use crate as libc;
-use crate::util;
-use crate::boxed::CBox;
+use crate::{self as libc, util, boxed::CBox};
 
 use core::slice;
 use core::ops::{Deref, DerefMut};
 
 //pub struct FromBytesWithNulError {}
 
+#[repr(transparent)]
 pub struct CStr { inner: libc::c_char }
 
 impl CStr {
@@ -43,7 +42,7 @@ impl CStr {
 
 	#[inline]
 	pub fn len(&self) -> usize {
-		unsafe { libc::strlen(self.as_ptr()) as usize }
+		unsafe { libc::strlen(self.as_ptr()) }
 	}
 
 	#[inline]
@@ -57,7 +56,7 @@ impl CStr {
 	}
 
 	#[inline]
-	pub fn as_bytes(&self) -> &[u8] {
+	pub fn to_bytes(&self) -> &[u8] {
 		unsafe { slice::from_raw_parts(
 			self.as_ptr().cast(),
 			self.len(),
@@ -65,13 +64,23 @@ impl CStr {
 	}
 
 	#[inline]
-	pub fn as_mut_bytes(&mut self) -> &mut [u8] {
+	pub fn to_mut_bytes(&mut self) -> &mut [u8] {
 		unsafe { slice::from_raw_parts_mut(
 			self.as_mut_ptr().cast(),
 			self.len(),
 		) }
 	}
 
+	#[inline]
+	pub fn to_str(&self) -> Result<&str, core::str::Utf8Error> {
+		core::str::from_utf8(self.to_bytes())
+	}
+
+	#[inline]
+	pub fn to_mut_str(&mut self) -> Result<&mut str, core::str::Utf8Error> {
+		core::str::from_utf8_mut(self.to_mut_bytes())
+	}
+
 	#[inline]
 	pub fn to_owned(self: &CStr) -> CString {
 		CString::from(self)
@@ -127,7 +136,7 @@ impl From<&[u8]> for CString {
 			CString::from_raw_unchecked(
 				util::must_succeed(libc::strndup(
 					s.as_ptr().cast(),
-					s.len() as libc::size_t,
+					s.len(),
 				))
 			)
 		}

src/main.rs

@@ -8,11 +8,11 @@ use core::fmt::Write;
 
 #[no_mangle]
 pub extern "C" fn main(_nargs: libc::c_int, _args: *const *const libc::c_char) -> libc::c_int {
-	let mut stdout = unsafe { libc::stdio::stdout() };
+	let mut stdout = libc::stdio::stdout();
 
 	{
 		let foo = cstr!("Foo!\n");
-		stdout.puts(foo);
+		let _ = stdout.puts(foo);
 	}
 
 	{
@@ -29,11 +29,12 @@ pub extern "C" fn main(_nargs: libc::c_int, _args: *const *const libc::c_char) -
 		let b = libc::boxed::CBox::new(42);
 		let _ = writeln!(stdout, "Bar: {}", b);
 	}
+
 	0
 }
 
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo) -> ! {
-	let _ = writeln!(unsafe { libc::stdio::stderr() }, "Panic: {}", info);
+	let _ = writeln!(libc::stdio::stderr(), "Panic: {}", info);
 	unsafe { libc::abort() }
 }