github.com/rigado/snapd@v2.42.5-go-mod+incompatible/interfaces/builtin/iio.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2016-2017 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 builtin
    21  
    22  import (
    23  	"fmt"
    24  	"path/filepath"
    25  	"regexp"
    26  	"strings"
    27  
    28  	"github.com/snapcore/snapd/interfaces"
    29  	"github.com/snapcore/snapd/interfaces/apparmor"
    30  	"github.com/snapcore/snapd/interfaces/udev"
    31  	"github.com/snapcore/snapd/snap"
    32  )
    33  
    34  const iioSummary = `allows access to a specific IIO device`
    35  
    36  const iioBaseDeclarationSlots = `
    37    iio:
    38      allow-installation:
    39        slot-snap-type:
    40          - gadget
    41          - core
    42      deny-auto-connection: true
    43  `
    44  
    45  const iioConnectedPlugAppArmor = `
    46  # Description: Give access to a specific IIO device on the system.
    47  
    48  ###IIO_DEVICE_PATH### rw,
    49  /sys/bus/iio/devices/###IIO_DEVICE_NAME###/ r,
    50  /sys/bus/iio/devices/###IIO_DEVICE_NAME###/** rwk,
    51  /sys/devices/**/###IIO_DEVICE_NAME###/ r,
    52  /sys/devices/**/###IIO_DEVICE_NAME###/** rwk,
    53  `
    54  
    55  // The type for iio interface
    56  type iioInterface struct{}
    57  
    58  // Getter for the name of the iio interface
    59  func (iface *iioInterface) Name() string {
    60  	return "iio"
    61  }
    62  
    63  func (iface *iioInterface) StaticInfo() interfaces.StaticInfo {
    64  	return interfaces.StaticInfo{
    65  		Summary:              iioSummary,
    66  		BaseDeclarationSlots: iioBaseDeclarationSlots,
    67  	}
    68  }
    69  
    70  func (iface *iioInterface) String() string {
    71  	return iface.Name()
    72  }
    73  
    74  // Pattern to match allowed iio device nodes. It is going to be used to check the
    75  // validity of the path attributes in case the udev is not used for
    76  // identification
    77  var iioControlDeviceNodePattern = regexp.MustCompile("^/dev/iio:device[0-9]+$")
    78  
    79  // Check validity of the defined slot
    80  func (iface *iioInterface) BeforePrepareSlot(slot *snap.SlotInfo) error {
    81  	// Validate the path
    82  	path, ok := slot.Attrs["path"].(string)
    83  	if !ok || path == "" {
    84  		return fmt.Errorf("%s slot must have a path attribute", iface.Name())
    85  	}
    86  
    87  	path = filepath.Clean(path)
    88  
    89  	if !iioControlDeviceNodePattern.MatchString(path) {
    90  		return fmt.Errorf("%s path attribute must be a valid device node", iface.Name())
    91  	}
    92  
    93  	return nil
    94  }
    95  
    96  func (iface *iioInterface) AppArmorConnectedPlug(spec *apparmor.Specification, plug *interfaces.ConnectedPlug, slot *interfaces.ConnectedSlot) error {
    97  	var path string
    98  	if err := slot.Attr("path", &path); err != nil {
    99  		return nil
   100  	}
   101  
   102  	cleanedPath := filepath.Clean(path)
   103  	snippet := strings.Replace(iioConnectedPlugAppArmor, "###IIO_DEVICE_PATH###", cleanedPath, -1)
   104  
   105  	// The path is already verified against a regular expression
   106  	// in BeforePrepareSlot so we can rely on its structure here and
   107  	// safely strip the '/dev/' prefix to get the actual name of
   108  	// the IIO device.
   109  	deviceName := strings.TrimPrefix(path, "/dev/")
   110  	snippet = strings.Replace(snippet, "###IIO_DEVICE_NAME###", deviceName, -1)
   111  
   112  	spec.AddSnippet(snippet)
   113  	return nil
   114  }
   115  
   116  func (iface *iioInterface) UDevConnectedPlug(spec *udev.Specification, plug *interfaces.ConnectedPlug, slot *interfaces.ConnectedSlot) error {
   117  	var path string
   118  	if err := slot.Attr("path", &path); err != nil {
   119  		return nil
   120  	}
   121  	spec.TagDevice(fmt.Sprintf(`KERNEL=="%s"`, strings.TrimPrefix(path, "/dev/")))
   122  	return nil
   123  }
   124  
   125  func (iface *iioInterface) AutoConnect(*snap.PlugInfo, *snap.SlotInfo) bool {
   126  	// Allow what is allowed in the declarations
   127  	return true
   128  }
   129  
   130  func init() {
   131  	registerIface(&iioInterface{})
   132  }