From 330a462737e5ed73934151fcef8d7fdca7573664 Mon Sep 17 00:00:00 2001
From: BlackHoleFox <blackholefoxdev@gmail.com>
Date: Sun, 1 Oct 2023 12:19:41 -0500
Subject: [PATCH] Move getentropy handling to a shared location for foreign
 item implementation

---
 src/tools/miri/src/shims/unix/macos/dlsym.rs  |  7 +++---
 .../src/shims/unix/macos/foreign_items.rs     | 23 +++++++++++++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/tools/miri/src/shims/unix/macos/dlsym.rs b/src/tools/miri/src/shims/unix/macos/dlsym.rs
index 63ad680de60fa..fa8094528757e 100644
--- a/src/tools/miri/src/shims/unix/macos/dlsym.rs
+++ b/src/tools/miri/src/shims/unix/macos/dlsym.rs
@@ -2,6 +2,7 @@ use rustc_middle::mir;
 
 use log::trace;
 
+use super::foreign_items::EvalContextExt as _;
 use crate::*;
 use helpers::check_arg_count;
 
@@ -38,10 +39,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         match dlsym {
             Dlsym::getentropy => {
                 let [ptr, len] = check_arg_count(args)?;
-                let ptr = this.read_pointer(ptr)?;
-                let len = this.read_target_usize(len)?;
-                this.gen_random(ptr, len)?;
-                this.write_null(dest)?;
+                let result = this.getentropy(ptr, len)?;
+                this.write_scalar(result, dest)?;
             }
         }
 
diff --git a/src/tools/miri/src/shims/unix/macos/foreign_items.rs b/src/tools/miri/src/shims/unix/macos/foreign_items.rs
index 0ee3cea05d508..b514097c5df08 100644
--- a/src/tools/miri/src/shims/unix/macos/foreign_items.rs
+++ b/src/tools/miri/src/shims/unix/macos/foreign_items.rs
@@ -109,6 +109,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 this.write_scalar(result, dest)?;
             }
 
+            // Random generation related shims
+            "getentropy" => {
+                let [buf, bufsize] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.getentropy(buf, bufsize)?;
+                this.write_scalar(result, dest)?;
+            }
+
             // Access to command-line arguments
             "_NSGetArgc" => {
                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
@@ -198,4 +206,19 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         Ok(EmulateByNameResult::NeedsJumping)
     }
+
+    fn getentropy(
+        &mut self,
+        buffer_op: &OpTy<'tcx, Provenance>,
+        length_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("macos", "getentropy");
+
+        let ptr = this.read_pointer(buffer_op)?;
+        let len = this.read_target_usize(length_op)?;
+        this.gen_random(ptr, len)?;
+
+        Ok(Scalar::from_i32(0)) // KERN_SUCCESS
+    }
 }