syscalls.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

  debug_printf ("uid: %d myself->gid: %d", uid, myself->gid);

  if (!wincap.has_security ()
      || (uid == myself->uid && !cygheap->user.groups.ischanged))
    {
      debug_printf ("Nothing happens");
      return 0;
    }

  if (uid == ILLEGAL_UID)
    {
      set_errno (EINVAL);
      return -1;
    }

  sigframe thisframe (mainthread);
  cygsid usersid;
  user_groups &groups = cygheap->user.groups;
  HANDLE ptok, sav_token;
  BOOL sav_impersonated, sav_token_is_internal_token;
  BOOL process_ok, explicitly_created_token = FALSE;
  struct passwd * pw_new;
  PSID origpsid, psid2 = NO_SID;

  pw_new = getpwuid32 (uid);
  if (!usersid.getfrompw (pw_new))
    {
      set_errno (EINVAL);
      return -1;
    }
  /* Save current information */
  sav_token = cygheap->user.token;
  sav_impersonated = cygheap->user.impersonated;

  RevertToSelf ();
  if (!OpenProcessToken (hMainProc, TOKEN_QUERY | TOKEN_ADJUST_DEFAULT, &ptok))
    {
      __seterrno ();
      goto failed;
    }
  /* Verify if the process token is suitable.
     Currently we do not try to differentiate between
	 internal tokens and others */
  process_ok = verify_token (ptok, usersid, groups);
  debug_printf ("Process token %sverified", process_ok ? "" : "not ");
  if (process_ok)
    {
      if (cygheap->user.issetuid ())
	cygheap->user.impersonated = FALSE;
      else
	{
	  CloseHandle (ptok);
	  goto success; /* No change */
	}
    }

  if (!process_ok && cygheap->user.token != INVALID_HANDLE_VALUE)
    {
      /* Verify if the current tokem is suitable */
      BOOL token_ok = verify_token (cygheap->user.token, usersid, groups,
				    &sav_token_is_internal_token);
      debug_printf ("Thread token %d %sverified",
		   cygheap->user.token, token_ok?"":"not ");
      if (!token_ok)
	cygheap->user.token = INVALID_HANDLE_VALUE;
      else
	{
	  /* Return if current token is valid */
	  if (cygheap->user.impersonated)
	    {
	      CloseHandle (ptok);
	      if (!ImpersonateLoggedOnUser (cygheap->user.token))
		system_printf ("Impersonating in seteuid failed: %E");
	      goto success; /* No change */
	    }
	}
    }

  /* Set process def dacl to allow access to impersonated token */
  char dacl_buf[MAX_DACL_LEN (5)];
  if (usersid != (origpsid =  cygheap->user.orig_sid ())) psid2 = usersid;
  if (sec_acl ((PACL) dacl_buf, FALSE, origpsid, psid2))
    {
      TOKEN_DEFAULT_DACL tdacl;
      tdacl.DefaultDacl = (PACL) dacl_buf;
      if (!SetTokenInformation (ptok, TokenDefaultDacl,
				&tdacl, sizeof dacl_buf))
	debug_printf ("SetTokenInformation"
		      "(TokenDefaultDacl): %E");
    }
  CloseHandle (ptok);

  if (!process_ok && cygheap->user.token == INVALID_HANDLE_VALUE)
    {
      /* If no impersonation token is available, try to
	 authenticate using NtCreateToken () or subauthentication. */
      cygheap->user.token = create_token (usersid, groups, pw_new);
      if (cygheap->user.token != INVALID_HANDLE_VALUE)
	explicitly_created_token = TRUE;
      else
	{
	  /* create_token failed. Try subauthentication. */
	  debug_printf ("create token failed, try subauthentication.");
	  cygheap->user.token = subauth (pw_new);
	  if (cygheap->user.token == INVALID_HANDLE_VALUE)
	    goto failed;
	}
    }

  /* If using the token, set info and impersonate */
  if (!process_ok)
    {
      /* If the token was explicitly created, all information has
	 already been set correctly. */
      if (!explicitly_created_token)
	{
	  /* Try setting owner to same value as user. */
	  if (!SetTokenInformation (cygheap->user.token, TokenOwner,
				    &usersid, sizeof usersid))
	    debug_printf ("SetTokenInformation(user.token, "
			  "TokenOwner): %E");
	  /* Try setting primary group in token to current group */
	  if (!SetTokenInformation (cygheap->user.token,
				    TokenPrimaryGroup,
				    &groups.pgsid, sizeof (cygsid)))
	    debug_printf ("SetTokenInformation(user.token, "
			  "TokenPrimaryGroup): %E");
	}
      /* Now try to impersonate. */
      if (!ImpersonateLoggedOnUser (cygheap->user.token))
	{
	  debug_printf ("ImpersonateLoggedOnUser %E");
	  __seterrno ();
	  goto failed;
	}
      cygheap->user.impersonated = TRUE;
    }

  /* If sav_token was internally created and is replaced, destroy it. */
  if (sav_token != INVALID_HANDLE_VALUE &&
      sav_token != cygheap->user.token &&
      sav_token_is_internal_token)
      CloseHandle (sav_token);
  cygheap->user.set_name (pw_new->pw_name);
  cygheap->user.set_sid (usersid);
success:
  myself->uid = uid;
  groups.ischanged = FALSE;
  return 0;

 failed:
  cygheap->user.token = sav_token;
  cygheap->user.impersonated = sav_impersonated;
  if (cygheap->user.issetuid ()
       && !ImpersonateLoggedOnUser (cygheap->user.token))
    system_printf ("Impersonating in seteuid failed: %E");
  return -1;
}

extern "C" int
seteuid (__uid16_t uid)
{
  return seteuid32 (uid16touid32 (uid));
}

/* setuid: POSIX 4.2.2.1 */
extern "C" int
setuid32 (__uid32_t uid)
{
  int ret = seteuid32 (uid);
  if (!ret)
    cygheap->user.real_uid = myself->uid;
  debug_printf ("real: %d, effective: %d", cygheap->user.real_uid, myself->uid);
  return ret;
}

extern "C" int
setuid (__uid16_t uid)
{
  return setuid32 (uid16touid32 (uid));
}

/* setegid: from System V.  */
extern "C" int
setegid32 (__gid32_t gid)
{
  if (!wincap.has_security () || gid == myself->gid)
    return 0;

  if (gid == ILLEGAL_GID)
    {
      set_errno (EINVAL);
      return -1;
    }

  sigframe thisframe (mainthread);
  user_groups * groups = &cygheap->user.groups;
  cygsid gsid;
  HANDLE ptok;

  struct __group32 * gr = getgrgid32 (gid);
  if (!gr || gr->gr_gid != gid || !gsid.getfromgr (gr))
    {
      set_errno (EINVAL);
      return -1;
    }
  myself->gid = gid;

  groups->update_pgrp (gsid);
  /* If impersonated, update primary group and revert */
  if (cygheap->user.issetuid ())
    {
      if (!SetTokenInformation (cygheap->user.token,
				TokenPrimaryGroup,
				&gsid, sizeof gsid))
	debug_printf ("SetTokenInformation(thread, "
		      "TokenPrimaryGroup): %E");
      RevertToSelf ();
    }
  if (!OpenProcessToken (hMainProc, TOKEN_ADJUST_DEFAULT, &ptok))
    debug_printf ("OpenProcessToken(): %E");
  else
    {
      if (!SetTokenInformation (ptok, TokenPrimaryGroup,
				&gsid, sizeof gsid))
	debug_printf ("SetTokenInformation(process, "
		      "TokenPrimaryGroup): %E");
      CloseHandle (ptok);
    }
  if (cygheap->user.issetuid ()
      && !ImpersonateLoggedOnUser (cygheap->user.token))
    system_printf ("Impersonating in setegid failed: %E");
  return 0;
}

extern "C" int
setegid (__gid16_t gid)
{
  return setegid32 (gid16togid32 (gid));
}

/* setgid: POSIX 4.2.2.1 */
extern "C" int
setgid32 (__gid32_t gid)
{
  int ret = setegid32 (gid);
  if (!ret)
    cygheap->user.real_gid = myself->gid;
  return ret;
}

extern "C" int
setgid (__gid16_t gid)
{
  int ret = setegid32 (gid16togid32 (gid));
  if (!ret)
    cygheap->user.real_gid = myself->gid;
  return ret;
}

/* chroot: privileged Unix system call.  */
/* FIXME: Not privileged here. How should this be done? */
extern "C" int
chroot (const char *newroot)
{
  sigframe thisframe (mainthread);
  path_conv path (newroot, PC_SYM_FOLLOW | PC_FULL | PC_POSIX);

  int ret;
  if (path.error)
    ret = -1;
  else if (!path.exists ())
    {
      set_errno (ENOENT);
      ret = -1;
    }
  else if (!path.isdir ())
    {
      set_errno (ENOTDIR);
      ret = -1;
    }
  else
    {
      cygheap->root.set (path.normalized_path, path);
      ret = 0;
    }

  syscall_printf ("%d = chroot (%s)", ret ? get_errno () : 0,
				      newroot ? newroot : "NULL");
  return ret;
}

extern "C" int
creat (const char *path, mode_t mode)
{
  sigframe thisframe (mainthread);
  return open (path, O_WRONLY | O_CREAT | O_TRUNC, mode);
}

extern "C" void
__assertfail ()
{
  exit (99);
}

extern "C" int
getw (FILE *fp)
{
  sigframe thisframe (mainthread);
  int w, ret;
  ret = fread (&w, sizeof (int), 1, fp);
  return ret != 1 ? EOF : w;
}

extern "C" int
putw (int w, FILE *fp)
{
  sigframe thisframe (mainthread);
  int ret;
  ret = fwrite (&w, sizeof (int), 1, fp);
  if (feof (fp) || ferror (fp))
    return -1;
  return 0;
}

extern "C" int
wcscmp (const wchar_t *s1, const wchar_t *s2)
{
  while (*s1  && *s1 == *s2)
    {
      s1++;
      s2++;
    }

  return (* (unsigned short *) s1) - (* (unsigned short *) s2);
}

extern "C" size_t
wcslen (const wchar_t *s1)
{
  int l = 0;
  while (s1[l])
    l++;
  return l;
}

/* FIXME: to do this right, maybe work out the usoft va_list machine
   and use wsvprintfW instead?
*/
extern "C" int
wprintf (const char *fmt, ...)
{
  va_list ap;
  int ret;

  va_start (ap, fmt);
  ret = vprintf (fmt, ap);
  va_end (ap);
  return ret;
}

extern "C" int
vhangup ()
{
  set_errno (ENOSYS);
  return -1;
}

extern "C" _PTR
memccpy (_PTR out, const _PTR in, int c, size_t len)
{
  const char *inc = (char *) in;
  char *outc = (char *) out;

  while (len)
    {
      char x = *inc++;
      *outc++ = x;
      if (x == c)
	return outc;
      len --;
    }
  return 0;
}

extern "C" int
nice (int incr)
{
  sigframe thisframe (mainthread);
  DWORD priority[] =
    {
      IDLE_PRIORITY_CLASS,
      IDLE_PRIORITY_CLASS,
      NORMAL_PRIORITY_CLASS,
      HIGH_PRIORITY_CLASS,
      REALTIME_PRIORITY_CLASS,
      REALTIME_PRIORITY_CLASS
    };
  int curr = 2;

  switch (GetPriorityClass (hMainProc))
    {
      case IDLE_PRIORITY_CLASS:
	curr = 1;
	break;
      case NORMAL_PRIORITY_CLASS:
	curr = 2;
	break;
      case HIGH_PRIORITY_CLASS:
	curr = 3;
	break;
      case REALTIME_PRIORITY_CLASS:
	curr = 4;
	break;
    }
  if (incr > 0)
    incr = -1;
  else if (incr < 0)
    incr = 1;

  if (SetPriorityClass (hMainProc, priority[curr + incr]) == FALSE)
    {
      __seterrno ();
      return -1;
    }

  return 0;
}

/*
 * Find the first bit set in I.
 */

extern "C" int
ffs (int i)
{
  static const unsigned char table[] =
    {
      0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
      6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
      7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
      7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
      8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
      8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
      8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
      8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8
    };
  unsigned long int a;
  unsigned long int x = i & -i;

  a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ?  16 : 24);

  return table[x >> a] + a;
}

extern "C" void
login (struct utmp *ut)
{
  sigframe thisframe (mainthread);
  register int fd;

  pututline (ut);
  if ((fd = open (_PATH_WTMP, O_WRONLY | O_APPEND | O_BINARY, 0)) >= 0)
    {
      (void) write (fd, (char *) ut, sizeof (struct utmp));
      (void) close (fd);
    }
}

/* It isn't possible to use unix-style I/O function in logout code because
cygwin's I/O subsystem may be inaccessible at logout () call time.
FIXME (cgf): huh?
*/
extern "C" int
logout (char *line)
{
  sigframe thisframe (mainthread);
  int res = 0;
  HANDLE ut_fd;
  static const char path_utmp[] = _PATH_UTMP;

  path_conv win32_path (path_utmp);
  if (win32_path.error)
    return 0;

  ut_fd = CreateFile (win32_path.get_win32 (),
		      GENERIC_READ | GENERIC_WRITE,
		      FILE_SHARE_READ | FILE_SHARE_WRITE,
		      &sec_none_nih, OPEN_EXISTING,
		      FILE_ATTRIBUTE_NORMAL, NULL);
  if (ut_fd != INVALID_HANDLE_VALUE)
    {
      struct utmp *ut;
      struct utmp ut_buf[100];
      /* FIXME: utmp file access is not 64 bit clean for now. */
      __off32_t pos = 0;		/* Position in file */
      DWORD rd;

      while (!res && ReadFile (ut_fd, ut_buf, sizeof ut_buf, &rd, NULL)
	     && rd != 0)
	{
	  struct utmp *ut_end = (struct utmp *) ((char *) ut_buf + rd);

	  for (ut = ut_buf; ut < ut_end; ut++, pos += sizeof (*ut))
	    if (ut->ut_name[0]
		&& strncmp (ut->ut_line, line, sizeof (ut->ut_line)) == 0)
	      /* Found the entry for LINE; mark it as logged out.  */
	      {
		/* Zero out entries describing who's logged in.  */
		bzero (ut->ut_name, sizeof (ut->ut_name));
		bzero (ut->ut_host, sizeof (ut->ut_host));
		time (&ut->ut_time);

		/* Now seek back to the position in utmp at which UT occured,
		   and write the new version of UT there.  */
		if ((SetFilePointer (ut_fd, pos, 0, FILE_BEGIN) != 0xFFFFFFFF)
		    && (WriteFile (ut_fd, (char *) ut, sizeof (*ut),
				   &rd, NULL)))
		  {
		    res = 1;
		    break;
		  }
	      }
	}

      CloseHandle (ut_fd);
    }

  return res;
}

static int utmp_fd = -2;
static char *utmp_file = (char *) _PATH_UTMP;

static struct utmp utmp_data;

extern "C" void
setutent ()
{
  sigframe thisframe (mainthread);
  if (utmp_fd == -2)
    {
      utmp_fd = open (utmp_file, O_RDWR);
    }
  lseek (utmp_fd, 0, SEEK_SET);
}

extern "C" void
endutent ()
{
  sigframe thisframe (mainthread);
  if (utmp_fd != -2)
    {
      close (utmp_fd);
      utmp_fd = -2;
    }
}

extern "C" void
utmpname (_CONST char *file)
{
  sigframe thisframe (mainthread);
  if (check_null_empty_str (file))
    {
      debug_printf ("Invalid file");
      return;
    }
  endutent ();
  utmp_file = strdup (file);
  debug_printf ("New UTMP file: %s", utmp_file);
}

extern "C" struct utmp *
getutent ()
{
  sigframe thisframe (mainthread);
  if (utmp_fd == -2)
    setutent ();
  if (read (utmp_fd, &utmp_data, sizeof (utmp_data)) != sizeof (utmp_data))
    return NULL;
  return &utmp_data;
}

extern "C" struct utmp *
getutid (struct utmp *id)
{
  sigframe thisframe (mainthread);
  if (check_null_invalid_struct_errno (id))
    return NULL;
  while (read (utmp_fd, &utmp_data, sizeof (utmp_data)) == sizeof (utmp_data))
    {
      switch (id->ut_type)
	{
	case RUN_LVL:
	case BOOT_TIME:
	case OLD_TIME:
	case NEW_TIME:
	  if (id->ut_type == utmp_data.ut_type)
	    return &utmp_data;
	  break;
	case INIT_PROCESS:
	case LOGIN_PROCESS:
	case USER_PROCESS:
	case DEAD_PROCESS:
	   if (strncmp (id->ut_id, utmp_data.ut_id, UT_IDLEN) == 0)
	    return &utmp_data;
	  break;
	default:
	  return NULL;
	}
    }
  return NULL;
}

extern "C" struct utmp *
getutline (struct utmp *line)
{
  sigframe thisframe (mainthread);
  if (check_null_invalid_struct_errno (line))
    return NULL;
  while (read (utmp_fd, &utmp_data, sizeof (utmp_data)) == sizeof (utmp_data))
    {
      if ((utmp_data.ut_type == LOGIN_PROCESS ||
	   utmp_data.ut_type == USER_PROCESS) &&
	  !strncmp (utmp_data.ut_line, line->ut_line,
		    sizeof (utmp_data.ut_line)))
	return &utmp_data;
    }
  return NULL;
}

extern "C" void
pututline (struct utmp *ut)
{
  sigframe thisframe (mainthread);
  if (check_null_invalid_struct (ut))
    return;
  setutent ();
  struct utmp *u;
  if ((u = getutid (ut)))
    lseek (utmp_fd, -sizeof(struct utmp), SEEK_CUR);
  else
    lseek (utmp_fd, 0, SEEK_END);
  (void) write (utmp_fd, (char *) ut, sizeof (struct utmp));
}