portable pipe

Author: matu3ba

lib/std/child_process.zig

@@ -1130,6 +1130,25 @@ pub const ChildProcess = struct {
     }
 };
 
+const PortPipeReturn = if (builtin.os.tag == .windows) [2]windows.HANDLE else [2]os.fd_t;
+
+/// Portable pipe creation without handle inheritance
+pub fn portablePipe() !PortPipeReturn {
+    // TODO think how to offer user an interface to lpSecurityDescriptor
+    var pipe_new: PortPipeReturn = undefined;
+    if (builtin.os.tag == .windows) {
+        const saAttr = windows.SECURITY_ATTRIBUTES{
+            .nLength = @sizeOf(windows.SECURITY_ATTRIBUTES),
+            .bInheritHandle = windows.FALSE,
+            .lpSecurityDescriptor = null,
+        };
+        try windowsMakeAsyncPipe(&pipe_new[os.pipe_rd], &pipe_new[os.pipe_wr], &saAttr);
+    } else {
+        pipe_new = try os.pipe2(@as(u32, os.O.CLOEXEC));
+    }
+    return pipe_new;
+}
+
 /// Expects `app_buf` to contain exactly the app name, and `dir_buf` to contain exactly the dir path.
 /// After return, `app_buf` will always contain exactly the app name and `dir_buf` will always contain exactly the dir path.
 /// Note: `app_buf` should not contain any leading path separators.

test/standalone/childprocess_extrapipe/parent.zig

@@ -19,22 +19,7 @@ pub fn main() !void {
     _ = it.next() orelse unreachable; // skip binary name
     const child_path = it.next() orelse unreachable;
 
-    // use posix convention: 0 read, 1 write
-    var pipe: if (builtin.os.tag == .windows) [2]windows.HANDLE else [2]os.fd_t = undefined;
-    if (builtin.os.tag == .windows) {
-        const saAttr = windows.SECURITY_ATTRIBUTES{
-            .nLength = @sizeOf(windows.SECURITY_ATTRIBUTES),
-            .bInheritHandle = windows.TRUE,
-            .lpSecurityDescriptor = null,
-        };
-        // create pipe without inheritance
-        try child_process.windowsMakeAsyncPipe(&pipe[pipe_rd], &pipe[pipe_wr], &saAttr);
-    } else {
-        // we could save setting and and unsetting 1 pipe end, but this would
-        // 1. allow more leak time and 2. makes things less consistent with windows
-        // TODO: benchmarks
-        pipe = try os.pipe2(@as(u32, os.O.CLOEXEC));
-    }
+    var pipe = try child_process.portablePipe();
 
     // write read side of pipe to string + add to spawn command
     var buf: [os.handleCharSize]u8 = comptime [_]u8{0} ** os.handleCharSize;