cosmopolitan/libc/runtime/winmain.greg.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                              │
│                                                                              │
│ 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/bits/bits.h"
#include "libc/bits/pushpop.h"
#include "libc/bits/weaken.h"
#include "libc/calls/internal.h"
#include "libc/calls/strace.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/fmt/fmt.h"
#include "libc/intrin/kprintf.h"
#include "libc/log/libfatal.internal.h"
#include "libc/macros.internal.h"
#include "libc/nexgen32e/bsr.h"
#include "libc/nexgen32e/rdtsc.h"
#include "libc/nt/console.h"
#include "libc/nt/enum/consolemodeflags.h"
#include "libc/nt/enum/filemapflags.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/enum/loadlibrarysearch.h"
#include "libc/nt/enum/pageflags.h"
#include "libc/nt/enum/version.h"
#include "libc/nt/files.h"
#include "libc/nt/memory.h"
#include "libc/nt/pedef.internal.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/teb.h"
#include "libc/runtime/directmap.internal.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/memtrack.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/internal.h"
#include "libc/str/tpenc.h"
#include "libc/str/utf16.h"

#define AT_EXECFN     31L
#define MAP_ANONYMOUS 32
#define MAP_PRIVATE   2
#define PROT_EXEC     4
#define PROT_READ     1
#define PROT_WRITE    2

/*
 * TODO: Why can't we allocate addresses above 4GB on Windows 7 x64?
 * TODO: How can we ensure we never overlap with KERNEL32.DLL?
 */

struct WinArgs {
  char *argv[4096];
  char *envp[4092];
  intptr_t auxv[2][2];
  char argblock[ARG_MAX];
  char envblock[ARG_MAX];
};

extern int __pid;
extern bool __nomultics;
extern const char kConsoleHandles[2];

static const short kConsoleModes[2] = {
    kNtEnableProcessedInput | kNtEnableLineInput | kNtEnableEchoInput |
        kNtEnableMouseInput | kNtEnableQuickEditMode | kNtEnableExtendedFlags |
        kNtEnableAutoPosition | kNtEnableInsertMode |
        kNtEnableVirtualTerminalInput,
    kNtEnableProcessedOutput | kNtEnableWrapAtEolOutput |
        kNtEnableVirtualTerminalProcessing,
};

forceinline void MakeLongDoubleLongAgain(void) {
  /* 8087 FPU Control Word
      IM: Invalid Operation ───────────────┐
      DM: Denormal Operand ───────────────┐│
      ZM: Zero Divide ───────────────────┐││
      OM: Overflow ─────────────────────┐│││
      UM: Underflow ───────────────────┐││││
      PM: Precision ──────────────────┐│││││
     PC: Precision Control ────────┐  ││││││
      {float,∅,double,long double} │  ││││││
     RC: Rounding Control ───────┐ │  ││││││
      {even, →-∞, →+∞, →0}       │┌┤  ││││││
                                ┌┤││  ││││││
                               d││││rr││││││*/
  int x87cw = 0b0000000000000000001101111111;
  asm volatile("fldcw\t%0" : /* no outputs */ : "m"(x87cw));
}

static noasan textwindows wontreturn noinstrument void WinMainNew(
    const char16_t *cmdline) {
  bool32 rc;
  int64_t h;
  int version;
  int i, count;
  int64_t hand;
  struct WinArgs *wa;
  const char16_t *env16;
  intptr_t stackaddr, allocaddr;
  size_t allocsize, argsize, stacksize;
  version = NtGetPeb()->OSMajorVersion;
  __oldstack = (intptr_t)__builtin_frame_address(0);
  if ((intptr_t)v_ntsubsystem == kNtImageSubsystemWindowsCui && version >= 10) {
    rc = SetConsoleCP(kNtCpUtf8);
    STRACE("SetConsoleCP(kNtCpUtf8) → %hhhd", rc);
    rc = SetConsoleOutputCP(kNtCpUtf8);
    STRACE("SetConsoleOutputCP(kNtCpUtf8) → %hhhd", rc);
    SetEnvironmentVariable(u"TERM", u"xterm-truecolor");
    for (i = 0; i < 2; ++i) {
      hand = GetStdHandle(kConsoleHandles[i]);
      rc = GetConsoleMode(hand, __ntconsolemode + i);
      STRACE("GetConsoleMode(%p, [%#x]) → %hhhd", hand, __ntconsolemode[i], rc);
      rc = SetConsoleMode(hand, kConsoleModes[i]);
      STRACE("SetConsoleMode(%p, %#x) → %hhhd", hand, kConsoleModes[i], rc);
    }
  }
  _mmi.p = _mmi.s;
  _mmi.n = ARRAYLEN(_mmi.s);
  argsize = ROUNDUP(sizeof(struct WinArgs), FRAMESIZE);
  stackaddr = GetStaticStackAddr(0);
  stacksize = GetStackSize();
  allocsize = argsize + stacksize;
  allocaddr = stackaddr - argsize;
  STRACE("WinMainNew() mapping %'zu byte arg block + stack at %p", allocsize,
         allocaddr);
  MapViewOfFileExNuma(
      (_mmi.p[0].h = CreateFileMappingNuma(
           -1, &kNtIsInheritable, kNtPageExecuteReadwrite, allocsize >> 32,
           allocsize, NULL, kNtNumaNoPreferredNode)),
      kNtFileMapWrite | kNtFileMapExecute, 0, 0, allocsize, (void *)allocaddr,
      kNtNumaNoPreferredNode);
  _mmi.p[0].x = allocaddr >> 16;
  _mmi.p[0].y = (allocaddr >> 16) + ((allocsize >> 16) - 1);
  _mmi.p[0].prot = PROT_READ | PROT_WRITE | PROT_EXEC;
  _mmi.p[0].flags = MAP_PRIVATE | MAP_ANONYMOUS;
  _mmi.i = 1;
  wa = (struct WinArgs *)allocaddr;
  STRACE("WinMainNew() loading arg block");
  count = GetDosArgv(cmdline, wa->argblock, ARRAYLEN(wa->argblock), wa->argv,
                     ARRAYLEN(wa->argv));
  for (i = 0; wa->argv[0][i]; ++i) {
    if (wa->argv[0][i] == '\\') {
      wa->argv[0][i] = '/';
    }
  }
  env16 = GetEnvironmentStrings();
  STRACE("WinMainNew() loading environment");
  GetDosEnviron(env16, wa->envblock, ARRAYLEN(wa->envblock) - 8, wa->envp,
                ARRAYLEN(wa->envp) - 1);
  FreeEnvironmentStrings(env16);
  wa->auxv[0][0] = pushpop(AT_EXECFN);
  wa->auxv[0][1] = (intptr_t)wa->argv[0];
  STRACE("WinMainNew() switching stacks");
  _jmpstack((char *)stackaddr + stacksize, cosmo, count, wa->argv, wa->envp,
            wa->auxv);
}

/**
 * Main function on Windows NT.
 *
 * The Cosmopolitan Runtime provides the following services, which aim
 * to bring Windows NT behavior closer in harmony with System Five:
 *
 * 1. We configure CMD.EXE for UTF-8 and enable ANSI colors on Win10.
 *
 * 2. Command line arguments are passed as a blob of UTF-16 text. We
 *    chop them up into an char *argv[] UTF-8 data structure, in
 *    accordance with the DOS conventions for argument quoting.
 *
 * 3. Environment variables are passed to us as a sorted UTF-16 double
 *    NUL terminated list. We translate this to char ** using UTF-8.
 *
 * 4. Allocates new stack at a high address. NT likes to choose a
 *    stack address that's beneath the program image. We want to be
 *    able to assume that stack addresses are located at higher
 *    addresses than heap and program memory.
 *
 * 5. Reconfigure x87 FPU so long double is actually long (80 bits).
 *
 * 6. Finally, we need fork. Since disagreeing with fork is axiomatic to
 *    Microsoft's engineering culture, we need to go to great lengths to
 *    have it anyway without breaking Microsoft's rules: using the WIN32
 *    API (i.e. not NTDLL) to copy MAP_PRIVATE pages via a pipe. It'd go
 *    faster if the COW pages CreateFileMappingNuma claims to have turns
 *    out to be true. Until then we have a "PC Scale" and entirely legal
 *    workaround that they hopefully won't block using Windows Defender.
 *
 * @param hInstance call GetModuleHandle(NULL) from main if you need it
 */
noasan textwindows noinstrument int64_t WinMain(int64_t hInstance,
                                                int64_t hPrevInstance,
                                                const char *lpCmdLine,
                                                int nCmdShow) {
  const char16_t *cmdline;
  extern char os asm("__hostos");
  extern uint64_t ts asm("kStartTsc");
  os = WINDOWS; /* madness https://news.ycombinator.com/item?id=21019722 */
  ts = rdtsc();
  __nomultics = true;
  __pid = GetCurrentProcessId();
  cmdline = GetCommandLine();
#ifdef SYSDEBUG
  /* sloppy flag-only check for early initialization */
  if (__strstr16(cmdline, u"--strace")) ++__strace;
#endif
  STRACE("WinMain()");
  MakeLongDoubleLongAgain();
  if (weaken(WinSockInit)) weaken(WinSockInit)();
  if (weaken(WinMainForked)) weaken(WinMainForked)();
  WinMainNew(cmdline);
}