php_embed_ub_write does not return on error

Description

sapi/embed/php_embed.c:

/* SAPIs only have unbuffered write operations. This is because PHP's output
 * buffering feature will handle any buffering of the output and invoke the
 * SAPI unbuffered write operation when it flushes the buffer.
 */
static size_t php_embed_ub_write(const char *str, size_t str_length)
{
	const char *ptr = str;
	size_t remaining = str_length;
	size_t ret;

	while (remaining > 0) {
		ret = php_embed_single_write(ptr, remaining);
		if (!ret) {
			php_handle_aborted_connection();
		}
		ptr += ret;
		remaining -= ret;
	}

	return str_length;
}

php_handle_aborted_connection does not always abort, i.e. if ignore_user_abort=1. So I sending fails and ret is 0, then remaining is never decremented and this loops forever.

It should probably return str_length - remaining after php_handle_aborted_connection().

PHP Version

master

Operating System

No response

Start in sapi/embed/php_embed.c at php_embed_ub_write and trace the php_embed_single_write error path followed by php_handle_aborted_connection. Verify that a zero-byte write cannot repeat indefinitely when the connection is not aborted. Done means the function returns the number of bytes written after the error instead of looping forever.