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a7262ed4b1
The timeout API uses signals, so we have documented not to use sleep(), but we can use nanosleep(2) since POSIX.1 explicitly specifies that it does not interact with signals. Let's provide timeout_usleep() for that. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://patch.msgid.link/20250514141927.159456-2-sgarzare@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Timeout API for single-threaded programs that use blocking
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* syscalls (read/write/send/recv/connect/accept).
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*
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* Copyright (C) 2017 Red Hat, Inc.
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*
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* Author: Stefan Hajnoczi <stefanha@redhat.com>
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*/
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/* Use the following pattern:
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*
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* timeout_begin(TIMEOUT);
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* do {
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* ret = accept(...);
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* timeout_check("accept");
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* } while (ret < 0 && ret == EINTR);
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* timeout_end();
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*/
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#include <stdlib.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <time.h>
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#include "timeout.h"
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static volatile bool timeout;
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/* SIGALRM handler function. Do not use sleep(2), alarm(2), or
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* setitimer(2) while using this API - they may interfere with each
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* other.
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*
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* If you need to sleep, please use timeout_sleep() provided by this API.
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*/
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void sigalrm(int signo)
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{
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timeout = true;
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}
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/* Start a timeout. Call timeout_check() to verify that the timeout hasn't
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* expired. timeout_end() must be called to stop the timeout. Timeouts cannot
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* be nested.
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*/
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void timeout_begin(unsigned int seconds)
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{
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alarm(seconds);
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}
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/* Exit with an error message if the timeout has expired */
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void timeout_check(const char *operation)
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{
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if (timeout) {
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fprintf(stderr, "%s timed out\n", operation);
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exit(EXIT_FAILURE);
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}
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}
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/* Stop a timeout */
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void timeout_end(void)
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{
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alarm(0);
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timeout = false;
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}
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/* Sleep in a timeout section.
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*
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* nanosleep(2) can be used with this API since POSIX.1 explicitly
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* specifies that it does not interact with signals.
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*/
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int timeout_usleep(useconds_t usec)
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{
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struct timespec ts = {
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.tv_sec = usec / 1000000,
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.tv_nsec = (usec % 1000000) * 1000,
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};
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return nanosleep(&ts, NULL);
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}
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