From 0c7405cf35b5ebd3ce2f8ebba84c1ea40cf5f6d7 Mon Sep 17 00:00:00 2001
From: Henrique Ferreiro <hferreiro@igalia.com>
Date: Mon, 22 Jun 2026 14:38:44 +0200
Subject: [PATCH] aosp: Fix GTest output on AOSP.

musl flushes stdout/stderr via writev, so wrap it and route
STDOUT_FILENO/STDERR_FILENO writes through SbLogRaw, which lands in Android
logcat.

Bug: 495203133
---
 starboard/android/shared/posix_emu/file.cc    | 34 +++++++++++++++++++
 .../build/config/starboard_target_type.gni    |  1 +
 2 files changed, 35 insertions(+)

diff --git a/starboard/android/shared/posix_emu/file.cc b/starboard/android/shared/posix_emu/file.cc
index 973b2596115b..78d3e425c4d2 100644
--- a/starboard/android/shared/posix_emu/file.cc
+++ b/starboard/android/shared/posix_emu/file.cc
@@ -13,7 +13,10 @@
 // limitations under the License.
 
 #include <fcntl.h>
+#include <sys/uio.h>
+#include <unistd.h>
 
+#include <string>
 #include <vector>
 
 #include "starboard/android/shared/asset_manager.h"
@@ -34,6 +37,7 @@ extern "C" {
 int __real_close(int fildes);
 int __real_open(const char* path, int oflag, ...);
 int __real_openat(int dirfd, const char* path, int oflag, ...);
+ssize_t __real_writev(int fd, const struct iovec* iov, int iovcnt);
 
 int __wrap_close(int fildes) {
   AssetManager* asset_manager = AssetManager::GetInstance();
@@ -68,4 +72,34 @@ int __wrap_open(const char* path, int oflag, ...) {
   return __wrap_openat(AT_FDCWD, path, oflag);
 }
 
+// Route stdout/stderr writes, which musl flushes via writev, through SbLogRaw
+// so they reach Android logcat.
+ssize_t __wrap_writev(int fd, const struct iovec* iov, int iovcnt) {
+  if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
+    ssize_t total = 0;
+    std::string buffer;
+    for (int i = 0; i < iovcnt; ++i) {
+      if (iov[i].iov_base && iov[i].iov_len > 0) {
+        buffer.append(static_cast<const char*>(iov[i].iov_base),
+                      iov[i].iov_len);
+        total += iov[i].iov_len;
+      }
+    }
+    // SbLogRaw is line-oriented; split on newlines and drop the terminators.
+    size_t start = 0, pos;
+    while ((pos = buffer.find('\n', start)) != std::string::npos) {
+      buffer[pos] = '\0';
+      if (pos > start) {
+        SbLogRaw(buffer.c_str() + start);
+      }
+      start = pos + 1;
+    }
+    if (start < buffer.size()) {
+      SbLogRaw(buffer.c_str() + start);
+    }
+    return total;
+  }
+  return __real_writev(fd, iov, iovcnt);
+}
+
 }  // extern "C"
diff --git a/starboard/build/config/starboard_target_type.gni b/starboard/build/config/starboard_target_type.gni
index e8078edb0a0b..62cbb97c3fb2 100644
--- a/starboard/build/config/starboard_target_type.gni
+++ b/starboard/build/config/starboard_target_type.gni
@@ -62,6 +62,7 @@ template("starboard_platform_target") {
           "-Wl,--wrap=open",
           "-Wl,--wrap=openat",
           "-Wl,--wrap=stat",
+          "-Wl,--wrap=writev",
         ]
       }
     }