From 67448289e538aadbf47eab77625901edc8760f07 Mon Sep 17 00:00:00 2001
From: Andrew Walbran <qwandor@google.com>
Date: Mon, 13 Jul 2020 14:53:27 +0100
Subject: [PATCH] Use platform abstraction around libc::__errno_location.

It has a different name on Android.

BUG=b:158290206
TEST=cargo test

Change-Id: I424d0ddf24c008a06570c709354c7c2dd9395738
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2294865
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Andrew Walbran <qwandor@google.com>
---
 io_uring/src/syscalls.rs |  5 +++--
 sys_util/src/errno.rs    | 13 ++++++++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/io_uring/src/syscalls.rs b/io_uring/src/syscalls.rs
index e52892b87d..e3c9f8630b 100644
--- a/io_uring/src/syscalls.rs
+++ b/io_uring/src/syscalls.rs
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+use std::io::Error;
 use std::os::unix::io::RawFd;
 use std::ptr::null_mut;
 
@@ -20,7 +21,7 @@ pub unsafe fn io_uring_setup(num_entries: usize, params: &io_uring_params) -> Re
         params as *const _,
     );
     if ret < 0 {
-        return Err(*libc::__errno_location());
+        return Err(Error::last_os_error().raw_os_error().unwrap());
     }
     Ok(ret as RawFd)
 }
@@ -35,7 +36,7 @@ pub unsafe fn io_uring_enter(fd: RawFd, to_submit: u64, to_wait: u64, flags: u32
         null_mut::<*mut c_void>(),
     );
     if ret < 0 {
-        return Err(*libc::__errno_location());
+        return Err(Error::last_os_error().raw_os_error().unwrap());
     }
     Ok(())
 }
diff --git a/sys_util/src/errno.rs b/sys_util/src/errno.rs
index 607d6b3b1f..ed0b38b294 100644
--- a/sys_util/src/errno.rs
+++ b/sys_util/src/errno.rs
@@ -6,7 +6,14 @@ use std::fmt::{self, Display};
 use std::io;
 use std::result;
 
-use libc::__errno_location;
+#[cfg(all(target_os = "android", test))]
+unsafe fn errno_location() -> *mut libc::c_int {
+    libc::__errno()
+}
+#[cfg(all(target_os = "linux", test))]
+unsafe fn errno_location() -> *mut libc::c_int {
+    libc::__errno_location()
+}
 
 /// An error number, retrieved from errno (man 3 errno), set by a libc
 /// function that returned an error.
@@ -25,7 +32,7 @@ impl Error {
     /// The result of this only has any meaning just after a libc call that returned a value
     /// indicating errno was set.
     pub fn last() -> Error {
-        Error(unsafe { *__errno_location() })
+        Error(io::Error::last_os_error().raw_os_error().unwrap())
     }
 
     /// Gets the errno for this error
@@ -65,6 +72,6 @@ pub fn errno_result<T>() -> Result<T> {
 #[cfg(test)]
 pub fn set_errno(e: i32) {
     unsafe {
-        *__errno_location() = e;
+        *errno_location() = e;
     }
 }