syslogd: Add generic timer API to replace exising buggy one
This patch adds a alarm()/SIGALRM based generic timer API to syslogd. The API takes care to wrap SIGALRM and serialize all timer events to a standard UNIX pipe(2) which syslogd can poll() for like any other incoming event. Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
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Joachim Nilsson
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ad686ca86d
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5ac6c39687
@ -34,7 +34,7 @@ AM_CFLAGS += -Wno-unused-result -Wno-unused-parameter -fno-strict-ali
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AM_CPPFLAGS = -DSYSCONFDIR=\"@sysconfdir@\" -DRUNSTATEDIR=\"@runstatedir@\"
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AM_CPPFLAGS += -D_BSD_SOURCE -D_DEFAULT_SOURCE
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syslogd_SOURCES = syslogd.c syslogd.h socket.c socket.h syslog.h queue.h compat.h
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syslogd_SOURCES = syslogd.c syslogd.h socket.c socket.h syslog.h timer.c timer.h queue.h compat.h
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syslogd_CPPFLAGS = $(AM_CPPFLAGS) -D_XOPEN_SOURCE=600
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syslogd_LDADD = $(LIBS) $(LIBOBJS)
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221
src/timer.c
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221
src/timer.c
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@ -0,0 +1,221 @@
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 2017-2019 Joachim Nilsson <troglobit@gmail.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <err.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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#include "queue.h"
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#include "socket.h"
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struct timer {
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LIST_ENTRY(timer) tmr_link;
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int tmr_period; /* period time in seconds */
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time_t tmr_timeout;
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void (*tmr_cb)(void *arg);
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void *tmr_arg;
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};
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static LIST_HEAD(, timer) tmr_head = LIST_HEAD_INITIALIZER();
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static struct timespec now;
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static int timer_fd[2];
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/*
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* what time is it?
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*/
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int timer_update(void)
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{
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return clock_gettime(CLOCK_MONOTONIC, &now);
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}
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time_t timer_now(void)
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{
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return now.tv_sec;
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}
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/*
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* create periodic timer (seconds)
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*/
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int timer_add(int period, void (*cb)(void *), void *arg)
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{
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struct timer *tmr;
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tmr = calloc(1, sizeof(*tmr));
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if (!tmr)
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return -1;
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tmr->tmr_period = period;
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tmr->tmr_cb = cb;
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tmr->tmr_arg = arg;
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LIST_INSERT_HEAD(&tmr_head, tmr, tmr_link);
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return 0;
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}
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static int __timer_start(void)
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{
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struct timer *next, *tmr;
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time_t sec;
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LIST_FOREACH(tmr, &tmr_head, tmr_link) {
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if (tmr->tmr_timeout == 0)
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tmr->tmr_timeout = timer_now() + tmr->tmr_period;
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}
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next = LIST_FIRST(&tmr_head);
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LIST_FOREACH(tmr, &tmr_head, tmr_link) {
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if (next->tmr_timeout > tmr->tmr_timeout)
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next = tmr;
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}
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sec = next->tmr_timeout - timer_now();
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if (sec <= 0)
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sec = 1;
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return alarm(sec);
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}
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/*
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* start timers
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*/
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int timer_start(void)
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{
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if (LIST_EMPTY(&tmr_head))
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return -1;
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timer_update();
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return __timer_start();
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}
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/*
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* callback for activity on pipe
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*/
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static void timer_cb(int sd, void *arg)
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{
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struct timer *tmr;
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char dummy;
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(void)read(sd, &dummy, 1);
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timer_update();
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LIST_FOREACH(tmr, &tmr_head, tmr_link) {
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if (tmr->tmr_timeout > timer_now())
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continue;
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if (tmr->tmr_cb)
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tmr->tmr_cb(tmr->tmr_arg);
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tmr->tmr_timeout = 0;
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}
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__timer_start();
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}
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/*
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* Write to pipe to create an event on SIGALRM
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*/
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static void sigalarm_handler(int signo)
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{
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(void)signo;
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(void)write(timer_fd[1], "!", 1);
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}
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/*
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* register signal pipe and callback
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*/
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int timer_init(void)
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{
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static int initialized = 0;
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struct sigaction sa;
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int rc;
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if (initialized)
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return 0;
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if (pipe(timer_fd)) {
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warn("pipe()");
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return -1;
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}
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sa.sa_handler = sigalarm_handler;
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sa.sa_flags = SA_RESTART;
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sigemptyset(&sa.sa_mask);
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if (sigaction(SIGALRM, &sa, NULL)) {
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warn("sigaction()");
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goto err;
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}
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rc = socket_register(timer_fd[0], NULL, timer_cb, NULL);
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if (rc < 0) {
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warn("socket_register()");
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goto err;
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}
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initialized = 1;
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return 0;
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err:
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close(timer_fd[0]);
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close(timer_fd[1]);
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return -1;
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}
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/*
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* deregister signal pipe and callbacks
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*/
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void timer_exit(void)
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{
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struct timer *tmr, *tmp;
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alarm(0);
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close(timer_fd[0]);
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close(timer_fd[1]);
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LIST_FOREACH_SAFE(tmr, &tmr_head, tmr_link, tmp) {
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LIST_REMOVE(tmr, tmr_link);
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free(tmr);
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}
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}
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/**
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* Local Variables:
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* indent-tabs-mode: t
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* c-file-style: "linux"
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* End:
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*/
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44
src/timer.h
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44
src/timer.h
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@ -0,0 +1,44 @@
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 2017-2019 Joachim Nilsson <troglobit@gmail.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef SYSKLOGD_TIMER_H_
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#define SYSKLOGD_TIMER_H_
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int timer_add (int period, void (*cb)(void *), void *arg);
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int timer_start (void);
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int timer_update (void);
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time_t timer_now (void);
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int timer_init (void);
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void timer_exit (void);
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#endif /* SYSKLOGD_TIMER_H_ */
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