Fix bugs and make improvements to redbean

- Abort if .init.lua fails
- Refactor redbean to use new append library
- Use first certificate if SNI routing fails
- Use function/data sections when building Lua
- Don't use self-signed auto-generated cert for client
- Add -D staging dirs to redbean lua module default path

libc/stdio/appendr.c

@@ -0,0 +1,71 @@
+/*-*- 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 2021 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/assert.h"
+#include "libc/dce.h"
+#include "libc/macros.internal.h"
+#include "libc/mem/mem.h"
+#include "libc/stdio/append.internal.h"
+#include "libc/str/str.h"
+
+#define W sizeof(size_t)
+
+/**
+ * Resets length of append buffer, e.g.
+ *
+ *     char *b = 0;
+ *     appends(&b, "hello");
+ *     appendr(&b, 1);
+ *     assert(!strcmp(b, "h"));
+ *     appendr(&b, 0);
+ *     assert(!strcmp(b, ""));
+ *     free(b);
+ *
+ * If `i` is greater than the current length then the extra bytes are
+ * filled with NUL characters.
+ *
+ * The resulting buffer is guarranteed to be NUL-terminated, i.e.
+ * `!b[appendz(b).i]` will be the case.
+ *
+ * @return `i` or -1 if `ENOMEM`
+ * @see appendz(b).i to get buffer length
+ */
+ssize_t appendr(char **b, size_t i) {
+  char *p;
+  struct appendz z;
+  assert(b);
+  z = appendz((p = *b));
+  z.n = ROUNDUP(i + 1, 8) + W;
+  if ((p = realloc(p, z.n))) {
+    z.n = malloc_usable_size(p);
+    assert(!(z.n & (W - 1)));
+    *b = p;
+  } else {
+    return -1;
+  }
+  if (i > z.i) {
+    memset(p, z.i, i - z.i);
+  }
+  z.i = i;
+  p[z.i] = 0;
+  if (!IsTiny() && W == 8) {
+    z.i |= (size_t)APPEND_COOKIE << 48;
+  }
+  *(size_t *)(p + z.n - W) = z.i;
+  return i;
+}