add stdio dup call for fd on windows

this ensures that another library calling _setmode or _dup2
does not affect our library output

fix #21264

src/init.c

@@ -317,9 +317,15 @@ static void *init_stdio_handle(uv_file fd,int readable)
 #ifndef _OS_WINDOWS_
  // Duplicate the file descriptor so we can later dup it over if we want to redirect
  // STDIO without having to worry about closing the associated libuv object.
+ // This also helps limit the impact other libraries can cause on our file handle.
  // On windows however, libuv objects remember streams by their HANDLE, so this is
  // unnecessary.
  fd = dup(fd);
+#else
+ if (type == UV_FILE) {
+ fd = _dup(fd);
+ _setmode(fd, _O_BINARY);
+ }
 #endif
  //jl_printf(JL_STDOUT, "%d: %d -- %d\n", fd, type, 0);
  switch(type) {
@@ -334,9 +340,14 @@ static void *init_stdio_handle(uv_file fd,int readable)
  case UV_UNKNOWN_HANDLE:
  // dup the descriptor with a new one pointing at the bit bucket ...
 #if defined(_OS_WINDOWS_)
- _dup2(_open("NUL", O_RDWR | O_BINARY, _S_IREAD | _S_IWRITE), fd);
+ fd = _open("NUL", O_RDWR | O_BINARY, _S_IREAD | _S_IWRITE);
 #else
- dup2(open("/dev/null", O_RDWR, S_IRUSR | S_IWUSR /* 0600 */ | S_IRGRP | S_IROTH /* 0644 */), fd);
+ {
+ int nullfd;
+ nullfd = open("/dev/null", O_RDWR, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH /* 0666 */);
+ dup2(nullfd, fd);
+ close(nullfd);
+ }
 #endif
  // ...and continue on as in the UV_FILE case
  case UV_FILE: