dcrt0.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

/* dcrt0.cc -- essentially the main() for the Cygwin dll

   Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <unistd.h>
#include <stdlib.h>
#include "glob.h"
#include "exceptions.h"
#include <ctype.h>
#include <limits.h>
#include <wingdi.h>
#include <winuser.h>
#include <errno.h>
#include "sigproc.h"
#include "pinfo.h"
#include "cygerrno.h"
#define NEED_VFORK
#include "perprocess.h"
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygheap.h"
#include "child_info_magic.h"
#include "perthread.h"
#include "shared_info.h"
#include "cygwin_version.h"
#include "dll_init.h"
#include "cygthread.h"

#define MAX_AT_FILE_LEVEL 10

#define PREMAIN_LEN (sizeof (user_data->premain) / sizeof (user_data->premain[0]))

HANDLE NO_COPY hMainProc;
HANDLE NO_COPY hMainThread;

sigthread NO_COPY mainthread;		// ID of the main thread

per_thread_waitq NO_COPY waitq_storage;
per_thread_vfork NO_COPY vfork_storage;
per_thread_signal_dispatch NO_COPY signal_dispatch_storage;

per_thread NO_COPY *threadstuff[] = {&waitq_storage,
				     &vfork_storage,
				     &signal_dispatch_storage,
				     NULL};

BOOL display_title;
BOOL strip_title_path;
BOOL allow_glob = TRUE;
codepage_type current_codepage = ansi_cp;

int cygwin_finished_initializing;

/* Used in SIGTOMASK for generating a bit for insertion into a sigset_t.
   This is subtracted from the signal number prior to shifting the bit.
   In older versions of cygwin, the signal was used as-is to shift the
   bit for masking.  So, we'll temporarily detect this and set it to zero
   for programs that are linked using older cygwins.  This is just a stopgap
   measure to allow an orderly transfer to the new, correct sigmask method. */
unsigned NO_COPY int signal_shift_subtract = 1;

ResourceLocks _reslock NO_COPY;
MTinterface _mtinterf;

bool NO_COPY _cygwin_testing;
unsigned NO_COPY _cygwin_testing_magic;

char NO_COPY almost_null[1];

extern "C"
{
  /* This is an exported copy of environ which can be used by DLLs
     which use cygwin.dll.  */
  char **__cygwin_environ;
  char ***main_environ;
  /* __progname used in getopt error message */
  char *__progname;
  struct _reent reent_data = _REENT_INIT(reent_data);
  struct per_process __cygwin_user_data =
  {/* initial_sp */ 0, /* magic_biscuit */ 0,
   /* dll_major */ CYGWIN_VERSION_DLL_MAJOR,
   /* dll_major */ CYGWIN_VERSION_DLL_MINOR,
   /* impure_ptr_ptr */ NULL, /* envptr */ NULL,
   /* malloc */ malloc, /* free */ free,
   /* realloc */ realloc,
   /* fmode_ptr */ NULL, /* main */ NULL, /* ctors */ NULL,
   /* dtors */ NULL, /* data_start */ NULL, /* data_end */ NULL,
   /* bss_start */ NULL, /* bss_end */ NULL,
   /* calloc */ calloc,
   /* premain */ {NULL, NULL, NULL, NULL},
   /* run_ctors_p */ 0,
   /* unused */ {0, 0, 0, 0, 0, 0, 0},
   /* forkee */ 0,
   /* hmodule */ NULL,
   /* api_major */ CYGWIN_VERSION_API_MAJOR,
   /* api_minor */ CYGWIN_VERSION_API_MINOR,
   /* unused2 */ {0, 0, 0, 0, 0},
   /* resourcelocks */ &_reslock, /* threadinterface */ &_mtinterf,
   /* impure_ptr */ &reent_data,
  };
  bool ignore_case_with_glob;
  int __declspec (dllexport) _check_for_executable = TRUE;
#ifdef DEBUGGING
  int pinger;
#endif
};

char *old_title;
char title_buf[TITLESIZE + 1];

static void
do_global_dtors (void)
{
  if (user_data->dtors)
    {
      void (**pfunc)() = user_data->dtors;
      while (*++pfunc)
	(*pfunc) ();
    }
}

static void __stdcall
do_global_ctors (void (**in_pfunc)(), int force)
{
  if (!force)
    {
      if (user_data->forkee || user_data->run_ctors_p)
	return;		// inherit constructed stuff from parent pid
      user_data->run_ctors_p = 1;
    }

  /* Run ctors backwards, so skip the first entry and find how many
     there are, then run them. */

  void (**pfunc)() = in_pfunc;

  while (*++pfunc)
    ;
  while (--pfunc > in_pfunc)
    (*pfunc) ();

  if (user_data->magic_biscuit == SIZEOF_PER_PROCESS)
    atexit (do_global_dtors);
}

/*
 * Replaces @file in the command line with the contents of the file.
 * There may be multiple @file's in a single command line
 * A \@file is replaced with @file so that echo \@foo would print
 * @foo and not the contents of foo.
 */
static int __stdcall
insert_file (char *name, char *&cmd)
{
  HANDLE f;
  DWORD size;

  f = CreateFile (name + 1,
		  GENERIC_READ,		 /* open for reading	*/
		  FILE_SHARE_READ,       /* share for reading	*/
		  &sec_none_nih,	 /* no security		*/
		  OPEN_EXISTING,	 /* existing file only	*/
		  FILE_ATTRIBUTE_NORMAL, /* normal file		*/
		  NULL);		 /* no attr. template	*/

  if (f == INVALID_HANDLE_VALUE)
    {
      debug_printf ("couldn't open file '%s', %E", name);
      return FALSE;
    }

  /* This only supports files up to about 4 billion bytes in
     size.  I am making the bold assumption that this is big
     enough for this feature */
  size = GetFileSize (f, NULL);
  if (size == 0xFFFFFFFF)
    {
      debug_printf ("couldn't get file size for '%s', %E", name);
      return FALSE;
    }

  int new_size = strlen (cmd) + size + 2;
  char *tmp = (char *) malloc (new_size);
  if (!tmp)
    {
      debug_printf ("malloc failed, %E");
      return FALSE;
    }

  /* realloc passed as it should */
  DWORD rf_read;
  BOOL rf_result;
  rf_result = ReadFile (f, tmp, size, &rf_read, NULL);
  CloseHandle (f);
  if (!rf_result || (rf_read != size))
    {
      debug_printf ("ReadFile failed, %E");
      return FALSE;
    }

  tmp[size++] = ' ';
  strcpy (tmp + size, cmd);
  cmd = tmp;
  return TRUE;
}

static inline int
isquote (char c)
{
  char ch = c;
  return ch == '"' || ch == '\'';
}

/* Step over a run of characters delimited by quotes */
static /*__inline*/ char *
quoted (char *cmd, int winshell)
{
  char *p;
  char quote = *cmd;

  if (!winshell)
    {
      char *p;
      strcpy (cmd, cmd + 1);
      if ((p = strchr (cmd, quote)) != NULL)
	strcpy (p, p + 1);
      else
	p = strchr (cmd, '\0');
      return p;
    }

  const char *s = quote == '\'' ? "'" : "\\\"";
  /* This must have been run from a Windows shell, so preserve
     quotes for globify to play with later. */
  while (*cmd && *++cmd)
    if ((p = strpbrk (cmd, s)) == NULL)
      {
	cmd = strchr (cmd, '\0');	// no closing quote
	break;
      }
    else if (*p == '\\')
      cmd = ++p;
    else if (quote == '"' && p[1] == '"')
      {
	*p = '\\';
	cmd = ++p;			// a quoted quote
      }
    else
      {
	cmd = p + 1;		// point to after end
	break;
      }
  return cmd;
}

/* Perform a glob on word if it contains wildcard characters.
   Also quote every character between quotes to force glob to
   treat the characters literally. */
static int __stdcall
globify (char *word, char **&argv, int &argc, int &argvlen)
{
  if (*word != '~' && strpbrk (word, "?*[\"\'(){}") == NULL)
    return 0;

  int n = 0;
  char *p, *s;
  int dos_spec = isdrive (word);
  if (!dos_spec && isquote (*word) && word[1] && word[2])
    dos_spec = isdrive (word + 1);

  /* We'll need more space if there are quoting characters in
     word.  If that is the case, doubling the size of the
     string should provide more than enough space. */
  if (strpbrk (word, "'\""))
    n = strlen (word);
  char pattern[strlen (word) + ((dos_spec + 1) * n) + 1];

  /* Fill pattern with characters from word, quoting any
     characters found within quotes. */
  for (p = pattern, s = word; *s != '\000'; s++, p++)
    if (!isquote (*s))
      {
	if (dos_spec && *s == '\\')
	  *p++ = '\\';
	*p = *s;
      }
    else
      {
	char quote = *s;
	while (*++s && *s != quote)
	  {
	    if (dos_spec || *s != '\\')
	      /* nothing */;
	    else if (s[1] == quote || s[1] == '\\')
	      s++;
	    *p++ = '\\';
	    *p++ = *s;
	  }
	if (*s == quote)
	  p--;
	if (*s == '\0')
	    break;
      }

  *p = '\0';

  glob_t gl;
  gl.gl_offs = 0;

  /* Attempt to match the argument.  Return just word (minus quoting) if no match. */
  if (glob (pattern, GLOB_TILDE | GLOB_NOCHECK | GLOB_BRACE | GLOB_QUOTE, NULL, &gl) || !gl.gl_pathc)
    return 0;

  /* Allocate enough space in argv for the matched filenames. */
  n = argc;
  if ((argc += gl.gl_pathc) > argvlen)
    {
      argvlen = argc + 10;
      argv = (char **) realloc (argv, (1 + argvlen) * sizeof (argv[0]));
    }

  /* Copy the matched filenames to argv. */
  char **gv = gl.gl_pathv;
  char **av = argv + n;
  while (*gv)
    {
      debug_printf ("argv[%d] = '%s'", n++, *gv);
      *av++ = *gv++;
    }

  /* Clean up after glob. */
  free (gl.gl_pathv);
  return 1;
}

/* Build argv, argc from string passed from Windows.  */

static void __stdcall
build_argv (char *cmd, char **&argv, int &argc, int winshell)
{
  int argvlen = 0;
  int nesting = 0;		// monitor "nesting" from insert_file

  argc = 0;
  argvlen = 0;
  argv = NULL;

  /* Scan command line until there is nothing left. */
  while (*cmd)
    {
      /* Ignore spaces */
      if (issep (*cmd))
	{
	  cmd++;
	  continue;
	}

      /* Found the beginning of an argument. */
      char *word = cmd;
      char *sawquote = NULL;
      while (*cmd)
	{
	  if (*cmd != '"' && (!winshell || *cmd != '\''))
	    cmd++;		// Skip over this character
	  else
	    /* Skip over characters until the closing quote */
	    {
	      sawquote = cmd;
	      cmd = quoted (cmd, winshell && argc > 0);
	    }
	  if (issep (*cmd))	// End of argument if space
	    break;
	}
      if (*cmd)
	*cmd++ = '\0';		// Terminate `word'

      /* Possibly look for @file construction assuming that this isn't
	 the very first argument and the @ wasn't quoted */
      if (argc && sawquote != word && *word == '@')
	{
	  if (++nesting > MAX_AT_FILE_LEVEL)
	    api_fatal ("Too many levels of nesting for %s", word);
	  if (insert_file (word, cmd))
	      continue;			// There's new stuff in cmd now
	}

      /* See if we need to allocate more space for argv */
      if (argc >= argvlen)
	{
	  argvlen = argc + 10;
	  argv = (char **) realloc (argv, (1 + argvlen) * sizeof (argv[0]));
	}

      /* Add word to argv file after (optional) wildcard expansion. */
      if (!winshell || !argc || !globify (word, argv, argc, argvlen))
	{
	  debug_printf ("argv[%d] = '%s'", argc, word);
	  argv[argc++] = word;
	}
    }

  argv[argc] = NULL;

  debug_printf ("argc %d", argc);
}

/* sanity and sync check */
void __stdcall
check_sanity_and_sync (per_process *p)
{
  /* Sanity check to make sure developers didn't change the per_process    */
  /* struct without updating SIZEOF_PER_PROCESS [it makes them think twice */
  /* about changing it].						   */
  if (sizeof (per_process) != SIZEOF_PER_PROCESS)
    {
      api_fatal ("per_process sanity check failed");
    }

  /* Make sure that the app and the dll are in sync. */

  /* Complain if older than last incompatible change */
  if (p->dll_major < CYGWIN_VERSION_DLL_EPOCH)
    api_fatal ("cygwin DLL and APP are out of sync -- DLL version mismatch %d < %d",
	       p->dll_major, CYGWIN_VERSION_DLL_EPOCH);

  /* magic_biscuit != 0 if using the old style version numbering scheme.  */
  if (p->magic_biscuit != SIZEOF_PER_PROCESS)
    api_fatal ("Incompatible cygwin .dll -- incompatible per_process info %d != %d",
	       p->magic_biscuit, SIZEOF_PER_PROCESS);

  /* Complain if incompatible API changes made */
  if (p->api_major != cygwin_version.api_major)
    api_fatal ("cygwin DLL and APP are out of sync -- API version mismatch %d < %d",
	       p->api_major, cygwin_version.api_major);

  if (CYGWIN_VERSION_DLL_MAKE_COMBINED (p->dll_major, p->dll_minor) <=
      CYGWIN_VERSION_DLL_BAD_SIGNAL_MASK)
    signal_shift_subtract = 0;
}

child_info NO_COPY *child_proc_info = NULL;
static MEMORY_BASIC_INFORMATION NO_COPY sm;

#define CYGWIN_GUARD ((wincap.has_page_guard ()) ? \
		     PAGE_EXECUTE_READWRITE|PAGE_GUARD : PAGE_NOACCESS)

// __inline__ void
extern void
alloc_stack_hard_way (child_info_fork *ci, volatile char *b)
{
  void *new_stack_pointer;
  MEMORY_BASIC_INFORMATION m;
  void *newbase;
  int newlen;
  LPBYTE curbot = (LPBYTE) sm.BaseAddress + sm.RegionSize;
  bool noguard;

  if (ci->stacktop > (LPBYTE) sm.AllocationBase && ci->stacktop < curbot)
    {
      newbase = curbot;
      newlen = (LPBYTE) ci->stackbottom - (LPBYTE) curbot;
      noguard = 1;
    }
  else
    {
      newbase = ci->stacktop;
      newlen = (DWORD) ci->stackbottom - (DWORD) ci->stacktop;
      noguard = 0;
    }
  if (!VirtualAlloc (newbase, newlen, MEM_RESERVE, PAGE_NOACCESS))
    api_fatal ("fork: can't reserve memory for stack %p - %p, %E",
		ci->stacktop, ci->stackbottom);

  new_stack_pointer = (void *) ((LPBYTE) ci->stackbottom - ci->stacksize);

  if (!VirtualAlloc (new_stack_pointer, ci->stacksize, MEM_COMMIT,
		     PAGE_EXECUTE_READWRITE))
    api_fatal ("fork: can't commit memory for stack %p(%d), %E",
	       new_stack_pointer, ci->stacksize);
  if (!VirtualQuery ((LPCVOID) new_stack_pointer, &m, sizeof m))
    api_fatal ("fork: couldn't get new stack info, %E");
  if (!noguard)
    {
      m.BaseAddress = (LPVOID)((DWORD)m.BaseAddress - 1);
      if (!VirtualAlloc ((LPVOID) m.BaseAddress, 1, MEM_COMMIT,
			 CYGWIN_GUARD))
	api_fatal ("fork: couldn't allocate new stack guard page %p, %E",
		   m.BaseAddress);
    }
  if (!VirtualQuery ((LPCVOID) m.BaseAddress, &m, sizeof m))
    api_fatal ("fork: couldn't get new stack info, %E");
  ci->stacktop = m.BaseAddress;
  *b = 0;
}

/* extend the stack prior to fork longjmp */

static void
alloc_stack (child_info_fork *ci)
{
  /* FIXME: adding 16384 seems to avoid a stack copy problem during
     fork on Win95, but I don't know exactly why yet. DJ */
  volatile char b[ci->stacksize + 16384];

  if (!VirtualQuery ((LPCVOID) &b, &sm, sizeof sm))
    api_fatal ("fork: couldn't get stack info, %E");

  if (sm.AllocationBase != ci->stacktop)
    alloc_stack_hard_way (ci, b + sizeof (b) - 1);
  else
    ci->stacksize = 0;

  return;
}

static NO_COPY int mypid = 0;
int _declspec(dllexport) __argc;
char _declspec(dllexport) **__argv;
vfork_save NO_COPY *main_vfork = NULL;

void
sigthread::init (const char *s)
{
  InitializeCriticalSection (&lock);
  id = GetCurrentThreadId ();
}

/* Take over from libc's crt0.o and start the application. Note the
   various special cases when Cygwin DLL is being runtime loaded (as
   opposed to being link-time loaded by Cygwin apps) from a non
   cygwin app via LoadLibrary.  */
static void
dll_crt0_1 ()
{
  /* According to [e-mail], the exception handler record must
     be on the stack.  */
  /* FIXME: Verify forked children get their exception handler set up ok. */
  exception_list cygwin_except_entry;

  /* Initialize SIGSEGV handling, etc. */
  init_exceptions (&cygwin_except_entry);

  /* Set the os_being_run global. */
  wincap.init ();
  check_sanity_and_sync (user_data);

  do_global_ctors (&__CTOR_LIST__, 1);

  /* Nasty static stuff needed by newlib -- point to a local copy of
     the reent stuff.
     Note: this MUST be done here (before the forkee code) as the
     fork copy code doesn't copy the data in libccrt0.cc (that's why we
     pass in the per_process struct into the .dll from libccrt0). */

  _impure_ptr = &reent_data;

  user_data->resourcelocks->Init ();
  user_data->threadinterface->Init (user_data->forkee);