From f506656876d445eb64c00721ca39007d08480e65 Mon Sep 17 00:00:00 2001
From: Thom Chiovoloni <thom@shift.click>
Date: Fri, 19 Aug 2022 16:02:48 -0700
Subject: [PATCH 1/2] Align android `sigaddset` impl with the reference impl
 from Bionic

---
 .../src/sys/unix/process/process_common.rs    | 26 ++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/library/std/src/sys/unix/process/process_common.rs b/library/std/src/sys/unix/process/process_common.rs
index bca1b65a7fc05..6ef02e2df775b 100644
--- a/library/std/src/sys/unix/process/process_common.rs
+++ b/library/std/src/sys/unix/process/process_common.rs
@@ -45,11 +45,31 @@ cfg_if::cfg_if! {
         }
         #[allow(dead_code)]
         pub unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
-            use crate::{slice, mem};
+            use crate::{
+                mem::{align_of, size_of},
+                slice,
+            };
+            use libc::{c_ulong, sigset_t};
+
+            // The implementations from bionic (android libc) type pun `sigset_t` as an
+            // array of `c_ulong`. This works, but lets add a smoke check to make sure
+            // that doesn't change.
+            const _: () = assert!(
+                align_of::<c_ulong>() == align_of::<sigset_t>()
+                    && (size_of::<sigset_t>() % size_of::<c_ulong>()) == 0
+            );
 
-            let raw = slice::from_raw_parts_mut(set as *mut u8, mem::size_of::<libc::sigset_t>());
             let bit = (signum - 1) as usize;
-            raw[bit / 8] |= 1 << (bit % 8);
+            if set.is_null() || bit < 0 || bit >= (8 * size_of::<sigset_t>()) {
+                crate::sys::unix::os::set_errno(libc::EINVAL);
+                return -1;
+            }
+            let raw = slice::from_raw_parts_mut(
+                set as *mut c_ulong,
+                size_of::<sigset_t>() / size_of::<c_ulong>(),
+            );
+            const LONG_BIT: usize = size_of::<c_ulong>() * 8;
+            raw[bit / LONG_BIT] |= 1 << (bit % LONG_BIT);
             return 0;
         }
     } else {

From 4ecf87619c8e2f6212a46501ea2aff18f5beb8c5 Mon Sep 17 00:00:00 2001
From: Thom Chiovoloni <thom@shift.click>
Date: Sun, 21 Aug 2022 01:08:33 -0700
Subject: [PATCH 2/2] Fix redundant comparison

---
 library/std/src/sys/unix/process/process_common.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/std/src/sys/unix/process/process_common.rs b/library/std/src/sys/unix/process/process_common.rs
index 6ef02e2df775b..6985f1d783087 100644
--- a/library/std/src/sys/unix/process/process_common.rs
+++ b/library/std/src/sys/unix/process/process_common.rs
@@ -60,7 +60,7 @@ cfg_if::cfg_if! {
             );
 
             let bit = (signum - 1) as usize;
-            if set.is_null() || bit < 0 || bit >= (8 * size_of::<sigset_t>()) {
+            if set.is_null() || bit >= (8 * size_of::<sigset_t>()) {
                 crate::sys::unix::os::set_errno(libc::EINVAL);
                 return -1;
             }