chrome-token-signin process should check whether stdin is not /dev/null

[plaes]

When accidentally starting chrome-token-signin process via window manager run dialog, process's stdin points to /dev/null and this causes process to run at 100% CPU.

Easiest way to test: chrome-token-signing </dev/null

Probably easiest way to fix it (assuming stdin only accepts input via pipes):

if (!isatty(fileno(stdin)) {
    // expecting stdin to be pipe
    exit(-1)
}

[martinpaljak]

This issue was moved to hwcrypto/hwcrypto-native#2