From 51cb36fa9b2c9c829050b6612bc6770f048db245 Mon Sep 17 00:00:00 2001
From: Andrzej Szombierski <anszom@users.noreply.github.com>
Date: Mon, 19 Nov 2018 17:53:55 +0100
Subject: [PATCH] fix: ensure that file descriptors 0/1/2 are opened at startup
 (#15555)

* fix: ensure that file descriptors 0/1/2 are opened at startup

This fixes an issue where the gpu subprocess was writing messages to a
random pipe or socket. The standard file desciptors are closed in
chromium's subprocesses because of an unfortunate interaction with
libuv's tty handling code leaving them with the FD_CLOEXEC flag.

* style: fix lint warnings
---
 atom/app/atom_main.cc | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/atom/app/atom_main.cc b/atom/app/atom_main.cc
index d9baf0dd993f..a739c0926823 100644
--- a/atom/app/atom_main.cc
+++ b/atom/app/atom_main.cc
@@ -24,10 +24,14 @@
 #include "base/win/windows_version.h"
 #include "content/public/app/sandbox_helper_win.h"
 #include "sandbox/win/src/sandbox_types.h"
-#elif defined(OS_LINUX)                   // defined(OS_WIN)
+#elif defined(OS_LINUX)  // defined(OS_WIN)
+#include <unistd.h>
+#include <cstdio>
 #include "atom/app/atom_main_delegate.h"  // NOLINT
 #include "content/public/app/content_main.h"
 #else  // defined(OS_LINUX)
+#include <unistd.h>
+#include <cstdio>
 #include "atom/app/atom_library_main.h"
 #endif  // defined(OS_MACOSX)
 
@@ -54,6 +58,25 @@ bool IsEnvSet(const char* name) {
 #endif
 }
 
+#if defined(OS_POSIX)
+void FixStdioStreams() {
+  // libuv may mark stdin/stdout/stderr as close-on-exec, which interferes
+  // with chromium's subprocess spawning. As a workaround, we detect if these
+  // streams are closed on startup, and reopen them as /dev/null if necessary.
+  // Otherwise, an unrelated file descriptor will be assigned as stdout/stderr
+  // which may cause various errors when attempting to write to them.
+  //
+  // For details see https://github.com/libuv/libuv/issues/2062
+  struct stat st;
+  if (fstat(STDIN_FILENO, &st) < 0 && errno == EBADF)
+    freopen("/dev/null", "r", stdin);
+  if (fstat(STDOUT_FILENO, &st) < 0 && errno == EBADF)
+    freopen("/dev/null", "w", stdout);
+  if (fstat(STDERR_FILENO, &st) < 0 && errno == EBADF)
+    freopen("/dev/null", "w", stderr);
+}
+#endif
+
 }  // namespace
 
 #if defined(OS_WIN)
@@ -155,6 +178,8 @@ int APIENTRY wWinMain(HINSTANCE instance, HINSTANCE, wchar_t* cmd, int) {
 #elif defined(OS_LINUX)  // defined(OS_WIN)
 
 int main(int argc, char* argv[]) {
+  FixStdioStreams();
+
 #if BUILDFLAG(ENABLE_RUN_AS_NODE)
   if (IsEnvSet(kRunAsNode)) {
     base::i18n::InitializeICU();
@@ -174,6 +199,8 @@ int main(int argc, char* argv[]) {
 #else  // defined(OS_LINUX)
 
 int main(int argc, char* argv[]) {
+  FixStdioStreams();
+
 #if BUILDFLAG(ENABLE_RUN_AS_NODE)
   if (IsEnvSet(kRunAsNode)) {
     return AtomInitializeICUandStartNode(argc, argv);