path.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

    ...
    FH_FLOPPY	250	from mount tab	\\.\Z:
*/
static int
get_raw_device_number (const char *name, const char *w32_path, int &unit)
{
  DWORD devn = FH_BAD;

  if (!w32_path)  /* New approach using fixed device names. */
    {
      if (deveqn ("st", 2))
	{
	  unit = digits (name + 2);
	  if (unit >= 0 && unit < 128)
	    devn = FH_TAPE;
	}
      else if (deveqn ("nst", 3))
	{
	  unit = digits (name + 3) + 128;
	  if (unit >= 128 && unit < 256)
	    devn = FH_TAPE;
	}
      else if (deveqn ("fd", 2))
	{
	  unit = digits (name + 2);
	  if (unit >= 0 && unit < 16)
	    devn = FH_FLOPPY;
	}
      else if (deveqn ("scd", 3))
	{
	  unit = digits (name + 3) + 16;
	  if (unit >= 16 && unit < 32)
	    devn = FH_FLOPPY;
	}
      else if (deveqn ("sd", 2) && isalpha (name[2]))
	{
	  unit = (cyg_tolower (name[2]) - 'a') * 16 + 32;
	  if (unit >= 32 && unit < 224)
	    if (!name[3])
	      devn = FH_FLOPPY;
	    else
	      {
		int d = digits (name + 3);
		if (d >= 1 && d < 16)
		  {
		    unit += d;
		    devn = FH_FLOPPY;
		  }
	      }
	}
    }
  else /* Backward compatible checking of mount table device mapping. */
    {
      if (wdeveqn ("tape", 4))
	{
	  unit = digits (w32_path + 4);
	  /* Norewind tape devices have leading n in name. */
	  if (deveqn ("n", 1))
	    unit += 128;
	  devn = FH_TAPE;
	}
      else if (wdeveqn ("physicaldrive", 13))
	{
	  unit = digits (w32_path + 13) * 16 + 32;
	  devn = FH_FLOPPY;
	}
      else if (isdrive (w32_path))
	{
	  unit = cyg_tolower (w32_path[0]) - 'a' + 224;
	  devn = FH_FLOPPY;
	}
    }
  return devn;
}

static int __stdcall get_device_number (const char *unix_path,
					const char *w32_path, int &unit)
  __attribute__ ((regparm(3)));
static int __stdcall
get_device_number (const char *unix_path, const char *w32_path, int &unit)
{
  DWORD devn = FH_BAD;
  unit = 0;

  if (*unix_path == '/' && udeveqn ("/dev/", 5))
    {
      devn = get_devn (unix_path, unit);
      if (devn == FH_BAD && *w32_path == '\\' && wdeveqn ("\\dev\\", 5))
	devn = get_devn (w32_path, unit);
      if (devn == FH_BAD && wdeveqn ("\\\\.\\", 4))
	devn = get_raw_device_number (unix_path + 5, w32_path + 4, unit);
      if (devn == FH_BAD)
	devn = get_raw_device_number (unix_path + 5, NULL, unit);
    }
  else
    {
      char *p = strrchr (unix_path, '/');
      if (p)
	unix_path = p + 1;
      if (udeveqn ("com", 3)
	 && (unit = digits (unix_path + 3)) >= 0 && unit < 100)
	devn = FH_SERIAL;
    }

  return devn;
}

/* Return TRUE if src_path is a Win32 device name, filling out the device
   name in win32_path */

static BOOL
win32_device_name (const char *src_path, char *win32_path,
		   DWORD &devn, int &unit)
{
  const char *devfmt;

  devn = get_device_number (src_path, win32_path, unit);

  if (devn == FH_BAD)
    return false;

  if ((devfmt = windows_device_names[FHDEVN (devn)]) == NULL)
    return false;
  switch (devn)
    {
      case FH_RANDOM:
	__small_sprintf (win32_path, devfmt, unit == 8 ? "" : "u");
	break;
      case FH_TAPE:
	__small_sprintf (win32_path, "\\Device\\Tape%d", unit % 128);
	break;
      case FH_FLOPPY:
	if (unit < 16)
	  __small_sprintf (win32_path, "\\Device\\Floppy%d", unit);
	else if (unit < 32)
	  __small_sprintf (win32_path, "\\Device\\CdRom%d", unit - 16);
	else if (unit < 224)
	  __small_sprintf (win32_path, "\\Device\\Harddisk%d\\Partition%d",
				       (unit - 32) / 16, unit % 16);
	else
	  __small_sprintf (win32_path, "\\DosDevices\\%c:", unit - 224 + 'A');
	break;
      default:
	__small_sprintf (win32_path, devfmt, unit);
	break;
    }
  return TRUE;
}

/* Normalize a Win32 path.
   /'s are converted to \'s in the process.
   All duplicate \'s, except for 2 leading \'s, are deleted.

   The result is 0 for success, or an errno error value.
   FIXME: A lot of this should be mergeable with the POSIX critter.  */
static int
normalize_win32_path (const char *src, char *dst)
{
  const char *src_start = src;
  char *dst_start = dst;
  char *dst_root_start = dst;
  bool beg_src_slash = isdirsep (src[0]);

  if (beg_src_slash && isdirsep (src[1]))
    {
      *dst++ = '\\';
      src++;
      if (src[1] == '.' && isdirsep (src[2]))
	{
	  *dst++ = '\\';
	  *dst++ = '.';
	  src += 2;
	}
    }
  else if (strchr (src, ':') == NULL && *src != '/')
    {
      if (!cygheap->cwd.get (dst, 0))
	return get_errno ();
      if (beg_src_slash)
	{
	  if (dst[1] == ':')
	    dst[2] = '\0';
	  else if (slash_unc_prefix_p (dst))
	    {
	      char *p = strpbrk (dst + 2, "\\/");
	      if (p && (p = strpbrk (p + 1, "\\/")))
		  *p = '\0';
	    }
	}
      if (strlen (dst) + 1 + strlen (src) >= MAX_PATH)
	{
	  debug_printf ("ENAMETOOLONG = normalize_win32_path (%s)", src);
	  return ENAMETOOLONG;
	}
      dst += strlen (dst);
      if (!beg_src_slash)
	*dst++ = '\\';
    }

  while (*src)
    {
      /* Strip duplicate /'s.  */
      if (SLASH_P (src[0]) && SLASH_P (src[1]))
	src++;
      /* Ignore "./".  */
      else if (src[0] == '.' && SLASH_P (src[1])
	       && (src == src_start || SLASH_P (src[-1])))
	src += 2;

      /* Backup if "..".  */
      else if (src[0] == '.' && src[1] == '.'
	       /* dst must be greater than dst_start */
	       && dst[-1] == '\\'
	       && (SLASH_P (src[2]) || src[2] == 0))
	{
	  /* Back up over /, but not if it's the first one.  */
	  if (dst > dst_root_start + 1)
	    dst--;
	  /* Now back up to the next /.  */
	  while (dst > dst_root_start + 1 && dst[-1] != '\\' && dst[-2] != ':')
	    dst--;
	  src += 2;
	  if (SLASH_P (*src))
	    src++;
	}
      /* Otherwise, add char to result.  */
      else
	{
	  if (*src == '/')
	    *dst++ = '\\';
	  else
	    *dst++ = *src;
	  ++src;
	}
      if ((dst - dst_start) >= MAX_PATH)
	return ENAMETOOLONG;
    }
  *dst = 0;
  debug_printf ("%s = normalize_win32_path (%s)", dst_start, src_start);
  return 0;
}

/* Various utilities.  */

/* slashify: Convert all back slashes in src path to forward slashes
   in dst path.  Add a trailing slash to dst when trailing_slash_p arg
   is set to 1. */

static void
slashify (const char *src, char *dst, int trailing_slash_p)
{
  const char *start = src;

  while (*src)
    {
      if (*src == '\\')
	*dst++ = '/';
      else
	*dst++ = *src;
      ++src;
    }
  if (trailing_slash_p
      && src > start
      && !isdirsep (src[-1]))
    *dst++ = '/';
  *dst++ = 0;
}

/* backslashify: Convert all forward slashes in src path to back slashes
   in dst path.  Add a trailing slash to dst when trailing_slash_p arg
   is set to 1. */

static void
backslashify (const char *src, char *dst, int trailing_slash_p)
{
  const char *start = src;

  while (*src)
    {
      if (*src == '/')
	*dst++ = '\\';
      else
	*dst++ = *src;
      ++src;
    }
  if (trailing_slash_p
      && src > start
      && !isdirsep (src[-1]))
    *dst++ = '\\';
  *dst++ = 0;
}

/* nofinalslash: Remove trailing / and \ from SRC (except for the
   first one).  It is ok for src == dst.  */

void __stdcall
nofinalslash (const char *src, char *dst)
{
  int len = strlen (src);
  if (src != dst)
    memcpy (dst, src, len + 1);
  while (len > 1 && SLASH_P (dst[--len]))
    dst[len] = '\0';
}

/* slash_unc_prefix_p: Return non-zero if PATH begins with //UNC/SHARE */

int __stdcall
slash_unc_prefix_p (const char *path)
{
  char *p = NULL;
  int ret = (isdirsep (path[0])
	     && isdirsep (path[1])
	     && isalpha (path[2])
	     && path[3] != 0
	     && !isdirsep (path[3])
	     && ((p = strpbrk (path + 3, "\\/")) != NULL));
  if (!ret || p == NULL)
    return ret;
  return ret && isalnum (p[1]);
}

/* conv_path_list: Convert a list of path names to/from Win32/POSIX. */

static void
conv_path_list (const char *src, char *dst, int to_posix_p)
{
  char *s;
  char *d = dst;
  char src_delim = to_posix_p ? ';' : ':';
  char dst_delim = to_posix_p ? ':' : ';';
  int (*conv_fn) (const char *, char *) = (to_posix_p
					   ? cygwin_conv_to_posix_path
					   : cygwin_conv_to_win32_path);

  char *srcbuf = (char *) alloca (strlen (src) + 1);

  for (;;)
    {
      s = strccpy (srcbuf, &src, src_delim);
      int len = s - srcbuf;
      if (len >= MAX_PATH)
	srcbuf[MAX_PATH - 1] = '\0';
      (*conv_fn) (len ? srcbuf : ".", d);
      if (!*src++)
	break;
      d = strchr (d, '\0');
      *d++ = dst_delim;
    }
}

/* init: Initialize the mount table.  */

void
mount_info::init ()
{
  nmounts = 0;

  /* Fetch the mount table and cygdrive-related information from
     the registry.  */
  from_registry ();
}

static void
set_flags (unsigned *flags, unsigned val)
{
  *flags = val;
  if (!(*flags & PATH_BINARY))
    {
      *flags |= PATH_TEXT;
      debug_printf ("flags: text (%p)", *flags & (PATH_TEXT | PATH_BINARY));
    }
  else
    {
      *flags |= PATH_BINARY;
      debug_printf ("flags: binary (%p)", *flags & (PATH_TEXT | PATH_BINARY));
    }
}

/* conv_to_win32_path: Ensure src_path is a pure Win32 path and store
   the result in win32_path.

   If win32_path != NULL, the relative path, if possible to keep, is
   stored in win32_path.  If the relative path isn't possible to keep,
   the full path is stored.

   If full_win32_path != NULL, the full path is stored there.

   The result is zero for success, or an errno value.

   {,full_}win32_path must have sufficient space (i.e. MAX_PATH bytes).  */

int
mount_info::conv_to_win32_path (const char *src_path, char *dst,
				DWORD &devn, int &unit, unsigned *flags,
				bool no_normalize)
{
  while (sys_mount_table_counter < cygwin_shared->sys_mount_table_counter)
    {
      init ();
      sys_mount_table_counter++;
    }
  int src_path_len = strlen (src_path);
  MALLOC_CHECK;
  unsigned dummy_flags;
  int chroot_ok = !cygheap->root.exists ();

  devn = FH_BAD;
  unit = 0;

  if (!flags)
    flags = &dummy_flags;

  *flags = 0;
  debug_printf ("conv_to_win32_path (%s)", src_path);

  if (src_path_len >= MAX_PATH)
    {
      debug_printf ("ENAMETOOLONG = conv_to_win32_path (%s)", src_path);
      return ENAMETOOLONG;
    }

  int i, rc;
  mount_item *mi = NULL;	/* initialized to avoid compiler warning */
  char pathbuf[MAX_PATH];

  if (dst == NULL)
    goto out;		/* Sanity check. */

  /* An MS-DOS spec has either a : or a \.  If this is found, short
     circuit most of the rest of this function. */
  if (strpbrk (src_path, ":\\") != NULL || slash_unc_prefix_p (src_path))
    {
      debug_printf ("%s already win32", src_path);
      rc = normalize_win32_path (src_path, dst);
      if (rc)
	{
	  debug_printf ("normalize_win32_path failed, rc %d", rc);
	  return rc;
	}

      set_flags (flags, (unsigned) set_flags_from_win32_path (dst));
      goto out;
    }

  /* Normalize the path, taking out ../../ stuff, we need to do this
     so that we can move from one mounted directory to another with relative
     stuff.

     eg mounting c:/foo /foo
     d:/bar /bar

     cd /bar
     ls ../foo

     should look in c:/foo, not d:/foo.

     We do this by first getting an absolute UNIX-style path and then
     converting it to a DOS-style path, looking up the appropriate drive
     in the mount table.  */

  if (no_normalize)
    strcpy (pathbuf, src_path);
  else
    {
      rc = normalize_posix_path (src_path, pathbuf);

      if (rc)
	{
	  debug_printf ("%d = conv_to_win32_path (%s)", rc, src_path);
	  return rc;
	}
    }

  /* See if this is a cygwin "device" */
  if (win32_device_name (pathbuf, dst, devn, unit))
    {
      *flags = MOUNT_BINARY;	/* FIXME: Is this a sensible default for devices? */
      rc = 0;
      goto out_no_chroot_check;
    }

  /* Check if the cygdrive prefix was specified.  If so, just strip
     off the prefix and transform it into an MS-DOS path. */
  MALLOC_CHECK;
  if (isproc (pathbuf))
    {
      devn = fhandler_proc::get_proc_fhandler (pathbuf);
      if (devn == FH_BAD)
	return ENOENT;
    }
  else if (iscygdrive (pathbuf))
    {
      int n = mount_table->cygdrive_len - 1;
      if (!pathbuf[n] ||