PHP Write to stdout via /proc/1/fd/1 using FFI (useful for logging inside a container)

use-ffi-to-write-to-file-via-low-level-standard-c-library-functions.php

<?php

// php can't write directly to a non-regular-file due to the php filesystem
// abstraction in place. But, we can use direct calls to the low level standard
// library to achieve this.

// normally, you should use the dio extension:
//   - https://pecl.php.net/package/dio
//   - https://github.com/php/pecl-system-dio/tree/master

// But this is how to achieve it with FFI:

$ffi = FFI::cdef("
  int open(const char *pathname, int flags /* mode_t mode */ );
  ssize_t write(int fildes, const void *buf, size_t nbyte);
  int close(int fildes);
");

$fd = $ffi->open('/proc/1/fd/1', 1);

$string = "Hello " . rand(0, 100) . '!!';
$string .= "\n";

$ffi->write($fd, $string, strlen($string));
$ffi->close($fd);