Make terminal ui binaries work well everywhere

Here's some screenshots of an emulator tui program that was compiled on Linux, then scp'd it to Windows, Mac, and FreeBSD. https://justine.storage.googleapis.com/blinkenlights-cmdexe.png https://justine.storage.googleapis.com/blinkenlights-imac.png https://justine.storage.googleapis.com/blinkenlights-freebsd.png https://justine.storage.googleapis.com/blinkenlights-lisp.png How is this even possible that we have a nontrivial ui binary that just works on Mac, Windows, Linux, and BSD? Surely a first ever achievement. Fixed many bugs. Bootstrapped John McCarthy's metacircular evaluator on bare metal in half the size of Altair BASIC (about 2.5kb) and ran it in emulator for fun and profit.
2025-07-06 19:28:29 +00:00 · 2020-10-10 21:18:53 -07:00 · 2020-10-10 21:18:53 -07:00 · 9e3e985ae5
commit 9e3e985ae5
parent 680daf1210
276 changed files with 7026 additions and 3790 deletions
--- a/libc/calls/setitimer-nt.c
+++ b/libc/calls/setitimer-nt.c
@ -0,0 +1,104 @@
+/*-*- 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/conv/conv.h"
+#include "libc/errno.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)) {
+      onntalarm(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;
+}