From d6002d68a2f15a286694fc36a8dfc599d4f5be68 Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Mon, 3 Mar 2025 15:29:33 -0500
Subject: [PATCH 1/2] Make `os2.random_string` use `context.random_generator`

This removes the data race caused by multiple threads using the
unprotected global `random_string_seed`, so long as no two threads share
the same random generator; this is the default case.

Additionally, `os2.random_string` now takes into account the full buffer
slice given to it.
---
 core/os/os2/internal_util.odin | 47 +++++++---------------------------
 1 file changed, 9 insertions(+), 38 deletions(-)

diff --git a/core/os/os2/internal_util.odin b/core/os/os2/internal_util.odin
index 164e1e1be..ce253d17b 100644
--- a/core/os/os2/internal_util.odin
+++ b/core/os/os2/internal_util.odin
@@ -3,6 +3,7 @@ package os2
 
 import "base:intrinsics"
 import "base:runtime"
+import "core:math/rand"
 
 
 // Splits pattern by the last wildcard "*", if it exists, and returns the prefix and suffix
@@ -84,45 +85,15 @@ concatenate :: proc(strings: []string, allocator: runtime.Allocator) -> (res: st
 	return string(buf), nil
 }
 
-
-
-@(private="file")
-random_string_seed: [2]u64
-
-@(init, private="file")
-init_random_string_seed :: proc() {
-	seed := u64(intrinsics.read_cycle_counter())
-	s := &random_string_seed
-	s[0] = 0
-	s[1] = (seed << 1) | 1
-	_ = next_random(s)
-	s[1] += seed
-	_ = next_random(s)
-}
-
-@(require_results)
-next_random :: proc(r: ^[2]u64) -> u64 {
-	old_state := r[0]
-	r[0] = old_state * 6364136223846793005 + (r[1]|1)
-	xor_shifted := (((old_state >> 59) + 5) ~ old_state) * 12605985483714917081
-	rot := (old_state >> 59)
-	return (xor_shifted >> rot) | (xor_shifted << ((-rot) & 63))
-}
-
 @(require_results)
 random_string :: proc(buf: []byte) -> string {
-	@(static, rodata) digits := "0123456789"
-
-	u := next_random(&random_string_seed)
-
-	b :: 10
-	i := len(buf)
-	for u >= b {
-		i -= 1
-		buf[i] = digits[u % b]
-		u /= b
+	for i := 0; i < len(buf); i += 16 {
+		n := rand.uint64()
+		end := min(i + 16, len(buf))
+		for j := i; j < end; j += 1 {
+			buf[j] = '0' + u8(n) % 10
+			n >>= 4
+		}
 	}
-	i -= 1
-	buf[i] = digits[u % b]
-	return string(buf[i:])
+	return string(buf)
 }

From 2d0dc44636c3f20bb1c41433a5d9cbd52098792b Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Mon, 3 Mar 2025 19:18:54 -0500
Subject: [PATCH 2/2] Shorten buffers used for `os2.random_string` results

This is needed now that `os2.random_string` fills the whole slice.
---
 core/os/os2/temp_file.odin | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/os/os2/temp_file.odin b/core/os/os2/temp_file.odin
index 5ca4e1453..e93117f02 100644
--- a/core/os/os2/temp_file.odin
+++ b/core/os/os2/temp_file.odin
@@ -20,7 +20,7 @@ create_temp_file :: proc(dir, pattern: string) -> (f: ^File, err: Error) {
 	prefix, suffix := _prefix_and_suffix(pattern) or_return
 	prefix = temp_join_path(dir, prefix) or_return
 
-	rand_buf: [32]byte
+	rand_buf: [10]byte
 	name_buf := make([]byte, len(prefix)+len(rand_buf)+len(suffix), temp_allocator())
 
 	attempts := 0
@@ -52,7 +52,7 @@ make_directory_temp :: proc(dir, pattern: string, allocator: runtime.Allocator)
 	prefix, suffix := _prefix_and_suffix(pattern) or_return
 	prefix = temp_join_path(dir, prefix) or_return
 
-	rand_buf: [32]byte
+	rand_buf: [10]byte
 	name_buf := make([]byte, len(prefix)+len(rand_buf)+len(suffix), temp_allocator())
 
 	attempts := 0