From 7894072528b56b566fd9cbd0124ae7a686d81999 Mon Sep 17 00:00:00 2001
From: Jinho Jang <verycosy@kakao.com>
Date: Tue, 11 Feb 2025 00:07:50 +0900
Subject: [PATCH] macos: increase child process stdio buffer size (#4694)

On macOS, when calling `spawn`, the child process's stdio buffer
size is 8192 bytes. This is due to the AF_UNIX socket buffer size
being 8192 bytes in the XNU kernel.

When large amounts of data are transferred through the child
process's stdio, this buffer size can cause performance issues.
To mitigate this, the buffer size has been increased to 65536
bytes, aligning it with the behavior on Linux.
---
 src/unix/process.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/unix/process.c b/src/unix/process.c
index f2038f2c..43e6b798 100644
--- a/src/unix/process.c
+++ b/src/unix/process.c
@@ -188,8 +188,12 @@ void uv__wait_children(uv_loop_t* loop) {
 static int uv__process_init_stdio(uv_stdio_container_t* container, int fds[2]) {
   int mask;
   int fd;
+  int ret;
+  int size;
+  int i;
 
   mask = UV_IGNORE | UV_CREATE_PIPE | UV_INHERIT_FD | UV_INHERIT_STREAM;
+  size = 64 * 1024;
 
   switch (container->flags & mask) {
   case UV_IGNORE:
@@ -199,8 +203,17 @@ static int uv__process_init_stdio(uv_stdio_container_t* container, int fds[2]) {
     assert(container->data.stream != NULL);
     if (container->data.stream->type != UV_NAMED_PIPE)
       return UV_EINVAL;
-    else
-      return uv_socketpair(SOCK_STREAM, 0, fds, 0, 0);
+    else {
+      ret = uv_socketpair(SOCK_STREAM, 0, fds, 0, 0);
+
+      if (ret == 0)
+        for (i = 0; i < 2; i++) {
+          setsockopt(fds[i], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
+          setsockopt(fds[i], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
+        }
+    }
+
+    return ret;
 
   case UV_INHERIT_FD:
   case UV_INHERIT_STREAM: