Make improvements

- Improved async signal safety of read() particularly for longjmp()
- Started adding cancel cleanup handlers for locks / etc on Windows
- Make /dev/tty work better particularly for uses like `foo | less`
- Eagerly read console input into a linked list, so poll can signal
- Fix some libc definitional bugs, which configure scripts detected

libc/proc/mkntcmdline.c

@@ -0,0 +1,146 @@
+/*-*- 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/proc/ntspawn.h"
+#include "libc/mem/mem.h"
+#include "libc/str/str.h"
+#include "libc/str/thompike.h"
+#include "libc/str/utf16.h"
+#include "libc/sysv/errfuns.h"
+
+#define APPEND(c)           \
+  do {                      \
+    cmdline[k++] = c;       \
+    if (k == ARG_MAX / 2) { \
+      return e2big();       \
+    }                       \
+  } while (0)
+
+static bool NeedsQuotes(const char *s) {
+  if (!*s) return true;
+  do {
+    switch (*s) {
+      case '"':
+      case ' ':
+      case '\t':
+      case '\v':
+      case '\n':
+        return true;
+      default:
+        break;
+    }
+  } while (*s++);
+  return false;
+}
+
+static inline int IsAlpha(int c) {
+  return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
+}
+
+// Converts System V argv to Windows-style command line.
+//
+// Escaping is performed and it's designed to round-trip with
+// GetDosArgv() or GetDosArgv(). This function does NOT escape
+// command interpreter syntax, e.g. $VAR (sh), %VAR% (cmd).
+//
+// TODO(jart): this needs fuzzing and security review
+//
+// @param cmdline is output buffer
+// @param argv is an a NULL-terminated array of UTF-8 strings
+// @return 0 on success, or -1 w/ errno
+// @raise E2BIG if everything is too huge
+// @see "Everyone quotes command line arguments the wrong way" MSDN
+// @see libc/runtime/getdosargv.c
+textwindows int mkntcmdline(char16_t cmdline[ARG_MAX / 2], char *const argv[]) {
+  uint64_t w;
+  wint_t x, y;
+  int slashes, n;
+  bool needsquote;
+  char *ansiargv[2];
+  size_t i, j, k, s;
+  if (!argv[0]) {
+    bzero(ansiargv, sizeof(ansiargv));
+    argv = ansiargv;
+  }
+  for (k = i = 0; argv[i]; ++i) {
+    if (i) APPEND(u' ');
+    if ((needsquote = NeedsQuotes(argv[i]))) APPEND(u'"');
+    for (slashes = j = 0;;) {
+      x = argv[i][j++] & 255;
+      if (x >= 0300) {
+        n = ThomPikeLen(x);
+        x = ThomPikeByte(x);
+        while (--n) {
+          if ((y = argv[i][j++] & 255)) {
+            x = ThomPikeMerge(x, y);
+          } else {
+            x = 0;
+            break;
+          }
+        }
+      }
+      if (!x) break;
+      if (x == '/' || x == '\\') {
+        if (!i) {
+          // turn / into \ for first argv[i]
+          x = '\\';
+          // turn \c\... into c:\ for first argv[i]
+          if (k == 2 && IsAlpha(cmdline[1]) && cmdline[0] == '\\') {
+            cmdline[0] = cmdline[1];
+            cmdline[1] = ':';
+          }
+        } else {
+          // turn stuff like `less /c/...`
+          //            into `less c:/...`
+          // turn stuff like `more <"/c/..."`
+          //            into `more <"c:/..."`
+          if (k > 3 && IsAlpha(cmdline[k - 1]) &&
+              (cmdline[k - 2] == '/' || cmdline[k - 2] == '\\') &&
+              (cmdline[k - 3] == '"' || cmdline[k - 3] == ' ')) {
+            cmdline[k - 2] = cmdline[k - 1];
+            cmdline[k - 1] = ':';
+          }
+        }
+      }
+      if (x == '\\') {
+        ++slashes;
+      } else if (x == '"') {
+        APPEND(u'"');
+        APPEND(u'"');
+        APPEND(u'"');
+      } else {
+        for (s = 0; s < slashes; ++s) {
+          APPEND(u'\\');
+        }
+        slashes = 0;
+        w = EncodeUtf16(x);
+        do {
+          APPEND(w);
+        } while ((w >>= 16));
+      }
+    }
+    for (s = 0; s < (slashes << needsquote); ++s) {
+      APPEND(u'\\');
+    }
+    if (needsquote) {
+      APPEND(u'"');
+    }
+  }
+  cmdline[k] = u'\0';
+  return 0;
+}