remove syscall shim from macos and move getrandom to linux module

Author: pvdrz

src/shims/foreign_items/posix.rs

@@ -333,21 +333,3 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         Ok(true)
     }
 }
-
-// Shims the posix 'getrandom()' syscall.
-fn getrandom<'tcx>(
-    this: &mut MiriEvalContext<'_, 'tcx>,
-    args: &[OpTy<'tcx, Tag>],
-    dest: PlaceTy<'tcx, Tag>,
-) -> InterpResult<'tcx> {
-    let ptr = this.read_scalar(args[0])?.not_undef()?;
-    let len = this.read_scalar(args[1])?.to_machine_usize(this)?;
-
-    // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
-    // neither of which have any effect on our current PRNG.
-    let _flags = this.read_scalar(args[2])?.to_i32()?;
-
-    this.gen_random(ptr, len as usize)?;
-    this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
-    Ok(())
-}

src/shims/foreign_items/posix/linux.rs

@@ -52,7 +52,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     id if id == sys_getrandom => {
                         // The first argument is the syscall id,
                         // so skip over it.
-                        super::getrandom(this, &args[1..], dest)?;
+                        getrandom(this, &args[1..], dest)?;
                     }
                     id if id == sys_statx => {
                         // The first argument is the syscall id,
@@ -65,7 +65,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
 
             "getrandom" => {
-                super::getrandom(this, args, dest)?;
+                getrandom(this, args, dest)?;
             }
 
             "sched_getaffinity" => {
@@ -79,3 +79,21 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         Ok(true)
     }
 }
+
+// Shims the posix 'getrandom()' syscall.
+fn getrandom<'tcx>(
+    this: &mut MiriEvalContext<'_, 'tcx>,
+    args: &[OpTy<'tcx, Tag>],
+    dest: PlaceTy<'tcx, Tag>,
+) -> InterpResult<'tcx> {
+    let ptr = this.read_scalar(args[0])?.not_undef()?;
+    let len = this.read_scalar(args[1])?.to_machine_usize(this)?;
+
+    // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
+    // neither of which have any effect on our current PRNG.
+    let _flags = this.read_scalar(args[2])?.to_i32()?;
+
+    this.gen_random(ptr, len as usize)?;
+    this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
+    Ok(())
+}

src/shims/foreign_items/posix/macos.rs

@@ -79,24 +79,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 this.write_null(dest)?;
             }
 
-            "syscall" => {
-                let sys_getrandom = this
-                    .eval_path_scalar(&["libc", "SYS_getrandom"])?
-                    .expect("Failed to get libc::SYS_getrandom")
-                    .to_machine_usize(this)?;
-
-                match this.read_scalar(args[0])?.to_machine_usize(this)? {
-                    // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
-                    // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
-                    id if id == sys_getrandom => {
-                        // The first argument is the syscall id,
-                        // so skip over it.
-                        super::getrandom(this, &args[1..], dest)?;
-                    }
-                    id => throw_unsup_format!("miri does not support syscall ID {}", id),
-                }
-            }
-
             _ => throw_unsup_format!("can't call foreign function: {}", link_name),
         };