From 69faa5626e3232829ca59adec2302b61b5396498 Mon Sep 17 00:00:00 2001
From: Alex Page <alex@anpage.me>
Date: Wed, 21 Jun 2023 21:40:58 -0400
Subject: [PATCH] Remove usage of libc functions

---
 src/confid.rs | 93 +++++++++++++++++++++++----------------------------
 1 file changed, 42 insertions(+), 51 deletions(-)

diff --git a/src/confid.rs b/src/confid.rs
index cb3a1b9..abed899 100644
--- a/src/confid.rs
+++ b/src/confid.rs
@@ -5,13 +5,13 @@
     clippy::too_many_arguments
 )]
 
-use std::ffi::{CStr, CString};
+use std::{
+    ffi::{CStr, CString},
+    ptr,
+};
 
 use thiserror::Error;
-extern "C" {
-    fn memcpy(_: *mut libc::c_void, _: *const libc::c_void, _: u64) -> *mut libc::c_void;
-    fn memset(_: *mut libc::c_void, _: i32, _: u64) -> *mut libc::c_void;
-}
+
 type size_t = u64;
 type int64_t = i64;
 type uint16_t = u16;
@@ -626,11 +626,12 @@ unsafe fn divisor_add(src1: *const TDivisor, src2: *const TDivisor, mut dst: *mu
         v[i as usize] = residue_mul(v[i as usize], c1[0_i32 as usize]);
         i += 1;
     }
-    memcpy(
-        tmp.as_mut_ptr() as *mut libc::c_void,
-        f.as_ptr() as *const libc::c_void,
-        (6_i32 as u64).wrapping_mul(::std::mem::size_of::<uint64_t>() as u64),
-    );
+    tmp[0] = f[0];
+    tmp[1] = f[1];
+    tmp[2] = f[2];
+    tmp[3] = f[3];
+    tmp[4] = f[4];
+    tmp[5] = f[5];
     tmpdeg = 5_i32;
     tmpdeg = polynomial_mul(
         1_i32,
@@ -675,11 +676,9 @@ unsafe fn divisor_add(src1: *const TDivisor, src2: *const TDivisor, mut dst: *mu
                 udiv.as_mut_ptr(),
             );
             vdeg -= ddeg;
-            memcpy(
-                v.as_mut_ptr() as *mut libc::c_void,
-                udiv.as_mut_ptr() as *const libc::c_void,
-                ((vdeg + 1_i32) as u64).wrapping_mul(::std::mem::size_of::<uint64_t>() as u64),
-            );
+            for i in 0..=vdeg {
+                v[i as usize] = udiv[i as usize];
+            }
         }
     }
     vdeg = polynomial_div_monic(
@@ -939,20 +938,18 @@ unsafe fn Mix(
     let half: size_t = bufSize.wrapping_div(2_i32 as u64);
     let mut external_counter = 0_i32;
     while external_counter < 4_i32 {
-        memset(
-            sha1_input.as_mut_ptr() as *mut libc::c_void,
-            0_i32,
-            ::std::mem::size_of::<[libc::c_uchar; 64]>() as u64,
+        for n in &mut sha1_input {
+            *n = 0;
+        }
+        ptr::copy_nonoverlapping(
+            buffer.offset(half as isize),
+            sha1_input.as_mut_ptr(),
+            half as usize,
         );
-        memcpy(
-            sha1_input.as_mut_ptr() as *mut libc::c_void,
-            buffer.offset(half as isize) as *const libc::c_void,
-            half,
-        );
-        memcpy(
-            sha1_input.as_mut_ptr().offset(half as isize) as *mut libc::c_void,
+        ptr::copy_nonoverlapping(
             key as *const libc::c_void,
-            keySize,
+            sha1_input.as_mut_ptr().offset(half as isize) as *mut libc::c_void,
+            keySize as usize,
         );
         sha1_input[half.wrapping_add(keySize) as usize] = 0x80_i32 as libc::c_uchar;
         sha1_input[(::std::mem::size_of::<[libc::c_uchar; 64]>() as u64).wrapping_sub(1_i32 as u64)
@@ -995,20 +992,14 @@ unsafe fn Unmix(
     let half: size_t = bufSize.wrapping_div(2_i32 as u64);
     let mut external_counter = 0_i32;
     while external_counter < 4_i32 {
-        memset(
-            sha1_input.as_mut_ptr() as *mut libc::c_void,
-            0_i32,
-            ::std::mem::size_of::<[libc::c_uchar; 64]>() as u64,
-        );
-        memcpy(
-            sha1_input.as_mut_ptr() as *mut libc::c_void,
-            buffer as *const libc::c_void,
-            half,
-        );
-        memcpy(
-            sha1_input.as_mut_ptr().offset(half as isize) as *mut libc::c_void,
-            key as *const libc::c_void,
-            keySize,
+        for n in &mut sha1_input {
+            *n = 0;
+        }
+        ptr::copy_nonoverlapping(buffer, sha1_input.as_mut_ptr(), half as usize);
+        ptr::copy_nonoverlapping(
+            key,
+            sha1_input.as_mut_ptr().offset(half as isize),
+            keySize as usize,
         );
         sha1_input[half.wrapping_add(keySize) as usize] = 0x80_i32 as libc::c_uchar;
         sha1_input[(::std::mem::size_of::<[libc::c_uchar; 64]>() as u64).wrapping_sub(1_i32 as u64)
@@ -1132,10 +1123,10 @@ unsafe fn Generate(
         ProductIDHigh: 0,
         KeySHA1: 0,
     };
-    memcpy(
-        &mut parsed as *mut C2RustUnnamed_4 as *mut libc::c_void,
+    ptr::copy_nonoverlapping(
         installation_id.as_mut_ptr() as *const libc::c_void,
-        ::std::mem::size_of::<C2RustUnnamed_4>() as u64,
+        &mut parsed as *mut C2RustUnnamed_4 as *mut libc::c_void,
+        std::mem::size_of::<C2RustUnnamed_4>(),
     );
     let productId1: u32 = (parsed.ProductIDLow & ((1_i32 << 17_i32) - 1_i32) as u64) as u32;
     let productId2: u32 =
@@ -1156,19 +1147,19 @@ unsafe fn Generate(
     }
     let mut keybuf: [libc::c_uchar; 16] = [0; 16];
     let mut hardware_id = parsed.HardwareID;
-    memcpy(
+    ptr::copy_nonoverlapping(
+        &mut hardware_id as *mut u64 as *const libc::c_void,
         keybuf.as_mut_ptr() as *mut libc::c_void,
-        &mut hardware_id as *mut uint64_t as *const libc::c_void,
-        8_i32 as u64,
+        8,
     );
     let mut productIdMixed: uint64_t = (productId1 as uint64_t) << 41_i32
         | (productId2 as uint64_t) << 58_i32
         | (productId3 as uint64_t) << 17_i32
         | productId4 as u64;
-    memcpy(
-        keybuf.as_mut_ptr().offset(8_i32 as isize) as *mut libc::c_void,
-        &mut productIdMixed as *mut uint64_t as *const libc::c_void,
-        8_i32 as u64,
+    ptr::copy_nonoverlapping(
+        &mut productIdMixed as *mut u64 as *const libc::c_void,
+        keybuf.as_mut_ptr().offset(8) as *mut libc::c_void,
+        8,
     );
     let mut d_0: TDivisor = TDivisor {
         u: [0; 2],