cosmopolitan/libc/calls/setitimer-nt.c

105 lines
4.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/itimerval.h"
#include "libc/errno.h"
#include "libc/fmt/conv.h"
#include "libc/log/check.h"
#include "libc/nexgen32e/nexgen32e.h"
#include "libc/nt/files.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/nt/thread.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/itimer.h"
#include "libc/sysv/errfuns.h"
/**
* @fileoverview Heartbreaking polyfill for SIGALRM on NT.
*
* Threads are used to trigger the SIGALRM handler, which should
* hopefully be an unfancy function like this:
*
* void OnAlarm(int sig, struct siginfo *si, struct ucontext *uc) {
* g_alarmed = true;
* }
*
* This is needed because WIN32 provides no obvious solutions for
* interrupting i/o operations on the standard input handle.
*/
static struct ItimerNt {
int64_t ith;
uint32_t tid;
struct itimerval itv;
} g_itimernt;
static uint32_t ItimerWorker(void *arg) {
do {
if (!WaitForSingleObject(g_itimernt.ith, -1)) {
__winalarm(NULL, 0, 0);
}
} while (g_itimernt.ith && g_itimernt.tid == GetCurrentThreadId());
return 0;
}
textwindows int setitimer$nt(int which, const struct itimerval *newvalue,
struct itimerval *out_opt_oldvalue) {
int32_t period;
int64_t ith, duetime;
if (which != ITIMER_REAL) return einval();
if (newvalue) {
if (newvalue->it_value.tv_sec && newvalue->it_value.tv_usec) {
if (!(ith = CreateWaitableTimer(NULL, false, NULL))) {
return __winerr();
}
duetime = -(newvalue->it_value.tv_sec * HECTONANOSECONDS +
newvalue->it_value.tv_usec * 10);
period = newvalue->it_value.tv_sec * 1000 +
div1000int64(newvalue->it_value.tv_usec);
if (!period && newvalue->it_value.tv_usec) period = 1;
if (!SetWaitableTimer(ith, &duetime, period, NULL, NULL, false)) {
errno = GetLastError();
CloseHandle(ith);
return -1;
}
} else {
ith = 0;
}
if (g_itimernt.ith) {
CloseHandle(g_itimernt.ith);
g_itimernt.ith = 0;
}
} else {
ith = 0;
}
if (out_opt_oldvalue) {
memcpy(out_opt_oldvalue, &g_itimernt.itv, sizeof(struct itimerval));
}
if (ith) {
g_itimernt.ith = ith;
memcpy(&g_itimernt.itv, newvalue, sizeof(struct itimerval));
CloseHandle(
CreateThread(NULL, STACKSIZE, ItimerWorker, NULL, 0, &g_itimernt.tid));
}
return 0;
}