Make exciting improvements

- Add Lua backtraces to redbean!
- Wipe serving keys after redbean forks
- Audit redbean to remove free via exit
- Log SSL client ciphersuite preferences
- Increase ASAN malloc() backtrace depth
- Make GetSslRoots() behave as a singleton
- Move leaks.c from LIBC_TESTLIB to LIBC_LOG
- Add undocumented %n to printf() for newlines
- Fix redbean memory leak reindexing inode change
- Fix redbean memory leak with Fetch() DNS object
- Restore original environ after __cxa_finalize()
- Make backtrace always work after __cxa_finalize()
- Introduce COUNTEXPR() diagnostic / benchmark tool
- Fix a few more instances of errno being clobbered
- Consolidate the ANSI color disabling internal APIs

libc/intrin/isdebuggerpresent.greg.c

@@ -0,0 +1,58 @@
+/*-*- 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                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/log/libfatal.internal.h"
+#include "libc/log/log.h"
+#include "libc/nexgen32e/vendor.internal.h"
+#include "libc/nt/struct/teb.h"
+#include "libc/sysv/consts/o.h"
+
+#define kBufSize 1024
+#define kPid     "TracerPid:\t"
+
+/**
+ * Determines if gdb, strace, windbg, etc. is controlling process.
+ * @return non-zero if attached, otherwise 0
+ */
+noasan noubsan int IsDebuggerPresent(bool force) {
+  /* asan runtime depends on this function */
+  int fd, res;
+  ssize_t got;
+  char *p, buf[1024];
+  if (!force) {
+    if (IsGenuineCosmo()) return 0;
+    if (getenv("HEISENDEBUG")) return 0;
+  }
+  if (IsWindows()) {
+    return NtGetPeb()->BeingDebugged; /* needs noasan */
+  } else {
+    res = 0;
+    if ((fd = __sysv_open("/proc/self/status", O_RDONLY, 0)) >= 0) {
+      if ((got = __sysv_read(fd, buf, sizeof(buf) - 1)) > 0) {
+        buf[got] = '\0';
+        if ((p = __strstr(buf, kPid))) {
+          p += sizeof(kPid) - 1;
+          res = __atoul(p);
+        }
+      }
+      __sysv_close(fd);
+    }
+    return res;
+  }
+}