github.com/kubiko/snapd@v0.0.0-20201013125620-d4f3094d9ddf/gadget/validate.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2019 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package gadget
    21  
    22  import (
    23  	"fmt"
    24  	"path/filepath"
    25  	"strings"
    26  
    27  	"github.com/snapcore/snapd/osutil"
    28  )
    29  
    30  func validateVolumeContentsPresence(gadgetSnapRootDir string, vol *LaidOutVolume) error {
    31  	// bare structure content is checked to exist during layout
    32  	// make sure that filesystem content source paths exist as well
    33  	for _, s := range vol.LaidOutStructure {
    34  		if !s.HasFilesystem() {
    35  			continue
    36  		}
    37  		for _, c := range s.Content {
    38  			realSource := filepath.Join(gadgetSnapRootDir, c.Source)
    39  			if !osutil.FileExists(realSource) {
    40  				return fmt.Errorf("structure %v, content %v: source path does not exist", s, c)
    41  			}
    42  			if strings.HasSuffix(c.Source, "/") {
    43  				// expecting a directory
    44  				if err := checkSourceIsDir(realSource + "/"); err != nil {
    45  					return fmt.Errorf("structure %v, content %v: %v", s, c, err)
    46  				}
    47  			}
    48  		}
    49  	}
    50  	return nil
    51  }
    52  
    53  // Validate checks whether the given directory contains valid gadget snap
    54  // metadata and a matching content, under the provided model constraints, which
    55  // are handled identically to ReadInfo().
    56  func Validate(gadgetSnapRootDir string, model Model) error {
    57  	info, err := ReadInfo(gadgetSnapRootDir, model)
    58  	if err != nil {
    59  		return fmt.Errorf("invalid gadget metadata: %v", err)
    60  	}
    61  
    62  	for name, vol := range info.Volumes {
    63  		lv, err := LayoutVolume(gadgetSnapRootDir, &vol, defaultConstraints)
    64  		if err != nil {
    65  			return fmt.Errorf("invalid layout of volume %q: %v", name, err)
    66  		}
    67  		if err := validateVolumeContentsPresence(gadgetSnapRootDir, lv); err != nil {
    68  			return fmt.Errorf("invalid volume %q: %v", name, err)
    69  		}
    70  	}
    71  
    72  	return nil
    73  }