From ade50978788f497796d8f36581560abdaeae5a5b Mon Sep 17 00:00:00 2001
From: Rob Bradford <robert.bradford@intel.com>
Date: Mon, 22 Feb 2021 15:43:48 +0000
Subject: [PATCH] arch: use libc::getrandom() instead of rand crate

This removes the last use of rand in our tree and the removal of several
dependencies.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
---
 Cargo.lock                    | 60 +----------------------------------
 arch/Cargo.toml               |  2 --
 arch/src/x86_64/interrupts.rs | 15 +++++----
 3 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4cbac8615..204cb9de9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -68,7 +68,6 @@ dependencies = [
  "libc",
  "linux-loader",
  "log 0.4.14",
- "rand",
  "serde",
  "serde_derive",
  "serde_json",
@@ -405,17 +404,6 @@ dependencies = [
  "wasi",
 ]
 
-[[package]]
-name = "getrandom"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee8025cf36f917e6a52cce185b7c7177689b838b7ec138364e50cc2277a56cf4"
-dependencies = [
- "cfg-if 0.1.10",
- "libc",
- "wasi",
-]
-
 [[package]]
 name = "gimli"
 version = "0.23.0"
@@ -877,12 +865,6 @@ dependencies = [
  "pnet_sys",
 ]
 
-[[package]]
-name = "ppv-lite86"
-version = "0.2.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.24"
@@ -912,46 +894,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "rand"
-version = "0.8.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
-dependencies = [
- "libc",
- "rand_chacha",
- "rand_core",
- "rand_hc",
-]
-
-[[package]]
-name = "rand_chacha"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e12735cf05c9e10bf21534da50a147b924d555dc7a547c42e6bb2d5b6017ae0d"
-dependencies = [
- "ppv-lite86",
- "rand_core",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a8b34ba8cfb21243bd8df91854c830ff0d785fff2e82ebd4434c2644cb9ada18"
-dependencies = [
- "getrandom 0.2.0",
-]
-
-[[package]]
-name = "rand_hc"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3190ef7066a446f2e7f42e239d161e905420ccab01eb967c9eb27d21b2322a73"
-dependencies = [
- "rand_core",
-]
-
 [[package]]
 name = "redox_syscall"
 version = "0.1.57"
@@ -964,7 +906,7 @@ version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "de0737333e7a9502c789a36d7c7fa6092a49895d4faa31ca5df163857ded2e9d"
 dependencies = [
- "getrandom 0.1.16",
+ "getrandom",
  "redox_syscall",
  "rust-argon2",
 ]
diff --git a/arch/Cargo.toml b/arch/Cargo.toml
index 75e1cc35a..b0d571f9c 100644
--- a/arch/Cargo.toml
+++ b/arch/Cargo.toml
@@ -26,5 +26,3 @@ vm-migration = { path = "../vm-migration" }
 git = "https://github.com/rust-vmm/linux-loader"
 features = ["elf", "bzimage"]
 
-[dev-dependencies]
-rand = "0.8.3"
diff --git a/arch/src/x86_64/interrupts.rs b/arch/src/x86_64/interrupts.rs
index be89787c6..73a00f3f5 100644
--- a/arch/src/x86_64/interrupts.rs
+++ b/arch/src/x86_64/interrupts.rs
@@ -84,10 +84,6 @@ pub fn set_lint(vcpu: &Arc<dyn hypervisor::Vcpu>) -> Result<()> {
 #[cfg(test)]
 #[cfg(feature = "kvm")]
 mod tests {
-
-    extern crate rand;
-    use self::rand::Rng;
-
     use super::*;
 
     const KVM_APIC_REG_SIZE: usize = 0x400;
@@ -111,8 +107,15 @@ mod tests {
 
     #[test]
     fn test_apic_delivery_mode() {
-        let mut rng = rand::thread_rng();
-        let mut v: Vec<u32> = (0..20).map(|_| rng.gen::<u32>()).collect();
+        let mut v: Vec<u32> = Vec::new();
+        v.resize(20, 0);
+
+        unsafe {
+            assert_eq!(
+                libc::getrandom(v.as_mut_ptr() as *mut _ as *mut libc::c_void, 80, 0),
+                80
+            );
+        }
 
         v.iter_mut()
             .for_each(|x| *x = set_apic_delivery_mode(*x, 2));