path.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

	  (pathbuf[n] == '/' && pathbuf[n + 1] == '.' && !pathbuf[n + 2]))
	{
	  unit = 0;
	  dst[0] = '\0';
	  if (mount_table->cygdrive_len > 1)
	    devn = FH_CYGDRIVE;
	}
      else if (cygdrive_win32_path (pathbuf, dst, unit))
	{
	  set_flags (flags, (unsigned) cygdrive_flags);
	  goto out;
	}
      else if (mount_table->cygdrive_len > 1)
	return ENOENT;
    }

  int chrooted_path_len;
  chrooted_path_len = 0;
  /* Check the mount table for prefix matches. */
  for (i = 0; i < nmounts; i++)
    {
      const char *path;
      int len;

      mi = mount + posix_sorted[i];
      if (!cygheap->root.exists ()
	  || (mi->posix_pathlen == 1 && mi->posix_path[0] == '/'))
	{
	  path = mi->posix_path;
	  len = mi->posix_pathlen;
	}
      else if (cygheap->root.posix_ok (mi->posix_path))
	{
	  path = cygheap->root.unchroot (mi->posix_path);
	  chrooted_path_len = len = strlen (path);
	}
      else
	{
	  chrooted_path_len = 0;
	  continue;
	}

      if (path_prefix_p (path, pathbuf, len))
	break;
    }

  if (i >= nmounts)
    {
      backslashify (pathbuf, dst, 0);	/* just convert */
      set_flags (flags, PATH_BINARY);
    }
  else
    {
      int n;
      const char *native_path;
      int posix_pathlen;
      if (chroot_ok || chrooted_path_len || mi->posix_pathlen != 1
	  || mi->posix_path[0] != '/')
	{
	  n = mi->native_pathlen;
	  native_path = mi->native_path;
	  posix_pathlen = chrooted_path_len ?: mi->posix_pathlen;
	  chroot_ok = 1;
	}
      else
	{
	  n = cygheap->root.native_length ();
	  native_path = cygheap->root.native_path ();
	  posix_pathlen = mi->posix_pathlen;
	  chroot_ok = 1;
	}
      memcpy (dst, native_path, n + 1);
      const char *p = pathbuf + posix_pathlen;
      if (*p == '/')
	/* nothing */;
      else if ((isdrive (dst) && !dst[2]) || *p)
	dst[n++] = '\\';
      strcpy (dst + n, p);
      backslashify (dst, dst, 0);
      set_flags (flags, (unsigned) mi->flags);
    }

  if (!isvirtual_dev (devn))
    win32_device_name (src_path, dst, devn, unit);

 out:
  MALLOC_CHECK;
  if (chroot_ok || cygheap->root.ischroot_native (dst))
    rc = 0;
  else
    {
      debug_printf ("attempt to access outside of chroot '%s = %s'",
		    cygheap->root.posix_path (), cygheap->root.native_path ());
      rc = ENOENT;
    }

 out_no_chroot_check:
  debug_printf ("src_path %s, dst %s, flags %p, rc %d", src_path, dst, *flags, rc);
  return rc;
}

/* cygdrive_posix_path: Build POSIX path used as the
   mount point for cygdrives created when there is no other way to
   obtain a POSIX path from a Win32 one. */

void
mount_info::cygdrive_posix_path (const char *src, char *dst, int trailing_slash_p)
{
  int len = cygdrive_len;

  memcpy (dst, cygdrive, len + 1);

  /* Now finish the path off with the drive letter to be used.
     The cygdrive prefix always ends with a trailing slash so
     the drive letter is added after the path. */
  dst[len++] = cyg_tolower (src[0]);
  if (!src[2] || (SLASH_P (src[2]) && !src[3]))
    dst[len++] = '\000';
  else
    {
      int n;
      dst[len++] = '/';
      if (SLASH_P (src[2]))
	n = 3;
      else
	n = 2;
      strcpy (dst + len, src + n);
    }
  slashify (dst, dst, trailing_slash_p);
}

int
mount_info::cygdrive_win32_path (const char *src, char *dst, int& unit)
{
  int res;
  const char *p = src + cygdrive_len;
  if (!isalpha (*p) || (!isdirsep (p[1]) && p[1]))
    {
      unit = -1;
      dst[0] = '\0';
      res = 0;
    }
  else
    {
      dst[0] = cyg_tolower (*p);
      dst[1] = ':';
      strcpy (dst + 2, p + 1);
      backslashify (dst, dst, !dst[2]);
      unit = dst[0];
      res = 1;
    }
  debug_printf ("src '%s', dst '%s'", src, dst);
  return res;
}

/* conv_to_posix_path: Ensure src_path is a POSIX path.

   The result is zero for success, or an errno value.
   posix_path must have sufficient space (i.e. MAX_PATH bytes).
   If keep_rel_p is non-zero, relative paths stay that way.  */

int
mount_info::conv_to_posix_path (const char *src_path, char *posix_path,
				int keep_rel_p)
{
  int src_path_len = strlen (src_path);
  int relative_path_p = !isabspath (src_path);
  int trailing_slash_p;

  if (src_path_len <= 1)
    trailing_slash_p = 0;
  else
    {
      const char *lastchar = src_path + src_path_len - 1;
      trailing_slash_p = SLASH_P (*lastchar) && lastchar[-1] != ':';
    }

  debug_printf ("conv_to_posix_path (%s, %s, %s)", src_path,
		keep_rel_p ? "keep-rel" : "no-keep-rel",
		trailing_slash_p ? "add-slash" : "no-add-slash");
  MALLOC_CHECK;

  if (src_path_len >= MAX_PATH)
    {
      debug_printf ("ENAMETOOLONG");
      return ENAMETOOLONG;
    }

  /* FIXME: For now, if the path is relative and it's supposed to stay
     that way, skip mount table processing. */

  if (keep_rel_p && relative_path_p)
    {
      slashify (src_path, posix_path, 0);
      debug_printf ("%s = conv_to_posix_path (%s)", posix_path, src_path);
      return 0;
    }

  char pathbuf[MAX_PATH];
  int rc = normalize_win32_path (src_path, pathbuf);
  if (rc != 0)
    {
      debug_printf ("%d = conv_to_posix_path (%s)", rc, src_path);
      return rc;
    }

  int pathbuflen = strlen (pathbuf);
  for (int i = 0; i < nmounts; ++i)
    {
      mount_item &mi = mount[native_sorted[i]];
      if (!path_prefix_p (mi.native_path, pathbuf, mi.native_pathlen))
	continue;

      if (cygheap->root.exists () && !cygheap->root.posix_ok (mi.posix_path))
	continue;

      /* SRC_PATH is in the mount table. */
      int nextchar;
      const char *p = pathbuf + mi.native_pathlen;

      if (!*p || !p[1])
	nextchar = 0;
      else if (isdirsep (*p))
	nextchar = -1;
      else
	nextchar = 1;

      int addslash = nextchar > 0 ? 1 : 0;
      if ((mi.posix_pathlen + (pathbuflen - mi.native_pathlen) + addslash) >= MAX_PATH)
	return ENAMETOOLONG;
      strcpy (posix_path, mi.posix_path);
      if (addslash)
	strcat (posix_path, "/");
      if (nextchar)
	slashify (p,
		  posix_path + addslash + (mi.posix_pathlen == 1 ? 0 : mi.posix_pathlen),
		  trailing_slash_p);

      if (cygheap->root.exists ())
	{
	  const char *p = cygheap->root.unchroot (posix_path);
	  memmove (posix_path, p, strlen (p) + 1);
	}
      goto out;
    }

  if (!cygheap->root.exists ())
    /* nothing */;
  else if (cygheap->root.ischroot_native (pathbuf))
    {
      const char *p = pathbuf + cygheap->root.native_length ();
      if (*p)
	slashify (p, posix_path, trailing_slash_p);
      else
	{
	  posix_path[0] = '/';
	  posix_path[1] = '\0';
	}
    }
  else
    return ENOENT;

  /* Not in the database.  This should [theoretically] only happen if either
     the path begins with //, or / isn't mounted, or the path has a drive
     letter not covered by the mount table.  If it's a relative path then the
     caller must want an absolute path (otherwise we would have returned
     above).  So we always return an absolute path at this point. */
  if (isdrive (pathbuf))
    cygdrive_posix_path (pathbuf, posix_path, trailing_slash_p);
  else
    {
      /* The use of src_path and not pathbuf here is intentional.
	 We couldn't translate the path, so just ensure no \'s are present. */
      slashify (src_path, posix_path, trailing_slash_p);
    }

out:
  debug_printf ("%s = conv_to_posix_path (%s)", posix_path, src_path);
  MALLOC_CHECK;
  return 0;
}

/* Return flags associated with a mount point given the win32 path. */

unsigned
mount_info::set_flags_from_win32_path (const char *p)
{
  for (int i = 0; i < nmounts; i++)
    {
      mount_item &mi = mount[native_sorted[i]];
      if (path_prefix_p (mi.native_path, p, mi.native_pathlen))
	return mi.flags;
    }
  return PATH_BINARY;
}

/* read_mounts: Given a specific regkey, read mounts from under its
   key. */

void
mount_info::read_mounts (reg_key& r)
{
  char posix_path[MAX_PATH];
  HKEY key = r.get_key ();
  DWORD i, posix_path_size;
  int res;

  /* Loop through subkeys */
  /* FIXME: we would like to not check MAX_MOUNTS but the heap in the
     shared area is currently statically allocated so we can't have an
     arbitrarily large number of mounts. */
  for (i = 0; ; i++)
    {
      char native_path[MAX_PATH];
      int mount_flags;

      posix_path_size = MAX_PATH;
      /* FIXME: if maximum posix_path_size is 256, we're going to
	 run into problems if we ever try to store a mount point that's
	 over 256 but is under MAX_PATH. */
      res = RegEnumKeyEx (key, i, posix_path, &posix_path_size, NULL,
			  NULL, NULL, NULL);

      if (res == ERROR_NO_MORE_ITEMS)
	break;
      else if (res != ERROR_SUCCESS)
	{
	  debug_printf ("RegEnumKeyEx failed, error %d!", res);
	  break;
	}

      /* Get a reg_key based on i. */
      reg_key subkey = reg_key (key, KEY_READ, posix_path, NULL);

      /* Fetch info from the subkey. */
      subkey.get_string ("native", native_path, sizeof (native_path), "");
      mount_flags = subkey.get_int ("flags", 0);

      /* Add mount_item corresponding to registry mount point. */
      res = mount_table->add_item (native_path, posix_path, mount_flags, false);
      if (res && get_errno () == EMFILE)
	break; /* The number of entries exceeds MAX_MOUNTS */
    }
}

/* from_registry: Build the entire mount table from the registry.  Also,
   read in cygdrive-related information from its registry location. */

void
mount_info::from_registry ()
{
  /* Use current mount areas if either user or system mount areas
     already exist.  Otherwise, import old mounts. */

  reg_key r;

  /* Retrieve cygdrive-related information. */
  read_cygdrive_info_from_registry ();

  nmounts = 0;

  /* First read mounts from user's table. */
  read_mounts (r);

  /* Then read mounts from system-wide mount table. */
  reg_key r1 (HKEY_LOCAL_MACHINE, KEY_READ, "SOFTWARE",
	      CYGWIN_INFO_CYGNUS_REGISTRY_NAME, CYGWIN_REGNAME,
	      CYGWIN_INFO_CYGWIN_MOUNT_REGISTRY_NAME,
	      NULL);
  read_mounts (r1);
}

/* add_reg_mount: Add mount item to registry.  Return zero on success,
   non-zero on failure. */
/* FIXME: Need a mutex to avoid collisions with other tasks. */

int
mount_info::add_reg_mount (const char * native_path, const char * posix_path, unsigned mountflags)
{
  int res = 0;

  /* Add the mount to the right registry location, depending on
     whether MOUNT_SYSTEM is set in the mount flags. */
  if (!(mountflags & MOUNT_SYSTEM)) /* current_user mount */
    {
      /* reg_key for user mounts in HKEY_CURRENT_USER. */
      reg_key reg_user;

      /* Start by deleting existing mount if one exists. */
      res = reg_user.kill (posix_path);
      if (res != ERROR_SUCCESS && res != ERROR_FILE_NOT_FOUND)
	goto err;

      /* Create the new mount. */
      reg_key subkey = reg_key (reg_user.get_key (),
				KEY_ALL_ACCESS,
				posix_path, NULL);
      res = subkey.set_string ("native", native_path);
      if (res != ERROR_SUCCESS)
	goto err;
      res = subkey.set_int ("flags", mountflags);
    }
  else /* local_machine mount */
    {
      /* reg_key for system mounts in HKEY_LOCAL_MACHINE. */
      reg_key reg_sys (HKEY_LOCAL_MACHINE, KEY_ALL_ACCESS, "SOFTWARE",
		       CYGWIN_INFO_CYGNUS_REGISTRY_NAME, CYGWIN_REGNAME,
		       CYGWIN_INFO_CYGWIN_MOUNT_REGISTRY_NAME,
		       NULL);

      /* Start by deleting existing mount if one exists. */
      res = reg_sys.kill (posix_path);
      if (res != ERROR_SUCCESS && res != ERROR_FILE_NOT_FOUND)
	goto err;

      /* Create the new mount. */
      reg_key subkey = reg_key (reg_sys.get_key (),
				KEY_ALL_ACCESS,
				posix_path, NULL);
      res = subkey.set_string ("native", native_path);
      if (res != ERROR_SUCCESS)
	goto err;
      res = subkey.set_int ("flags", mountflags);

      sys_mount_table_counter++;
      cygwin_shared->sys_mount_table_counter++;
    }

  return 0; /* Success */
 err:
  __seterrno_from_win_error (res);
  return -1;
}

/* del_reg_mount: delete mount item from registry indicated in flags.
   Return zero on success, non-zero on failure.*/
/* FIXME: Need a mutex to avoid collisions with other tasks. */

int
mount_info::del_reg_mount (const char * posix_path, unsigned flags)
{
  int res;

  if (!(flags & MOUNT_SYSTEM))	/* Delete from user registry */
    {
      reg_key reg_user (KEY_ALL_ACCESS,
			CYGWIN_INFO_CYGWIN_MOUNT_REGISTRY_NAME, NULL);
      res = reg_user.kill (posix_path);
    }
  else					/* Delete from system registry */
    {
      sys_mount_table_counter++;
      cygwin_shared->sys_mount_table_counter++;
      reg_key reg_sys (HKEY_LOCAL_MACHINE, KEY_ALL_ACCESS, "SOFTWARE",
		       CYGWIN_INFO_CYGNUS_REGISTRY_NAME, CYGWIN_REGNAME,
		       CYGWIN_INFO_CYGWIN_MOUNT_REGISTRY_NAME,
		       NULL);
      res = reg_sys.kill (posix_path);
    }

  if (res != ERROR_SUCCESS)
    {
      __seterrno_from_win_error (res);
      return -1;
    }

  return 0; /* Success */
}

/* read_cygdrive_info_from_registry: Read the default prefix and flags
   to use when creating cygdrives from the special user registry
   location used to store cygdrive information. */

void
mount_info::read_cygdrive_info_from_registry ()
{
  /* reg_key for user path prefix in HKEY_CURRENT_USER. */
  reg_key r;

  if (r.get_string (CYGWIN_INFO_CYGDRIVE_PREFIX, cygdrive, sizeof (cygdrive), "") != 0)
    {
      /* Didn't find the user path prefix so check the system path prefix. */

      /* reg_key for system path prefix in HKEY_LOCAL_MACHINE.  */
      reg_key r2 (HKEY_LOCAL_MACHINE, KEY_READ, "SOFTWARE",
		 CYGWIN_INFO_CYGNUS_REGISTRY_NAME, CYGWIN_REGNAME,
		 CYGWIN_INFO_CYGWIN_MOUNT_REGISTRY_NAME,
		 NULL);

      if (r2.get_string (CYGWIN_INFO_CYGDRIVE_PREFIX, cygdrive,
	  sizeof (cygdrive), ""))
	strcpy (cygdrive, CYGWIN_INFO_CYGDRIVE_DEFAULT_PREFIX);
      cygdrive_flags = r2.get_int (CYGWIN_INFO_CYGDRIVE_FLAGS, MOUNT_CYGDRIVE);
      slashify (cygdrive, cygdrive, 1);
      cygdrive_len = strlen (cygdrive);