in init/init.c [259:270]
void init_console() {
// init process needs to set up a tty for the container and this is likely
// not the correct way to do this, although it works when compiling with
// musl-gcc.
const char *console_path = "/dev/console";
die_on(freopen(console_path, "r", stdin) == NULL,
"freopen failed for stdin");
die_on(freopen(console_path, "w", stdout) == NULL,
"freopen failed for stdout");
die_on(freopen(console_path, "w", stderr) == NULL,
"freopen failed for stderr");
}