cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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timeout.c (1284B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Timeout API for single-threaded programs that use blocking
      3 * syscalls (read/write/send/recv/connect/accept).
      4 *
      5 * Copyright (C) 2017 Red Hat, Inc.
      6 *
      7 * Author: Stefan Hajnoczi <stefanha@redhat.com>
      8 */
      9
     10/* Use the following pattern:
     11 *
     12 *   timeout_begin(TIMEOUT);
     13 *   do {
     14 *       ret = accept(...);
     15 *       timeout_check("accept");
     16 *   } while (ret < 0 && ret == EINTR);
     17 *   timeout_end();
     18 */
     19
     20#include <stdlib.h>
     21#include <stdbool.h>
     22#include <unistd.h>
     23#include <stdio.h>
     24#include "timeout.h"
     25
     26static volatile bool timeout;
     27
     28/* SIGALRM handler function.  Do not use sleep(2), alarm(2), or
     29 * setitimer(2) while using this API - they may interfere with each
     30 * other.
     31 */
     32void sigalrm(int signo)
     33{
     34	timeout = true;
     35}
     36
     37/* Start a timeout.  Call timeout_check() to verify that the timeout hasn't
     38 * expired.  timeout_end() must be called to stop the timeout.  Timeouts cannot
     39 * be nested.
     40 */
     41void timeout_begin(unsigned int seconds)
     42{
     43	alarm(seconds);
     44}
     45
     46/* Exit with an error message if the timeout has expired */
     47void timeout_check(const char *operation)
     48{
     49	if (timeout) {
     50		fprintf(stderr, "%s timed out\n", operation);
     51		exit(EXIT_FAILURE);
     52	}
     53}
     54
     55/* Stop a timeout */
     56void timeout_end(void)
     57{
     58	alarm(0);
     59	timeout = false;
     60}