Module: XenStore::Utils

Defined in:
lib/xsrb/utils.rb

Overview

XenStore::Utils implements utility methods which are unlikely to be required by users but are used by the rest of the module

Class Method Summary collapse

Class Method Details

.error(n) ⇒ Exception

Convert an error number or symbol to an Errno exception

Parameters:

  • n (Integer, Symbol) —

    An Integer or symbol representing the Errno exception to return.

Returns:

  • (Exception) —

    The Exception representing the provided type of error.



68
69
70
71
72
73
74
 
# File 'lib/xsrb/utils.rb', line 68

def error(n)
  if n.is_a? Integer
    @errno_exception_map[n]
  else
    Errno.send(n)
  end
end

.next_request_id ⇒ Integer

Get the next request ID to contact XenStore with.

Returns:

  • (Integer) —

    The next ID in the sequence.



79
80
81
82
83
84
 
# File 'lib/xsrb/utils.rb', line 79

def next_request_id
  @reqid += 1

  # Ensure no larger than uint32_t which is used in xs_wire.h
  @reqid %= MAX_UINT
end

.unix_socket_path ⇒ String

Get the path of the XenStore unix socket.

Returns:

  • (String) —

    The path to the XenStore unix socket.



89
90
91
92
93
 
# File 'lib/xsrb/utils.rb', line 89

def unix_socket_path
  dp = '/var/run/xenstored'
  ENV['XENSTORED_PATH'] || File.join(ENV['XENSTORED_RUNDIR'] || dp,
                                     'socket')
end

.valid_path?(path) ⇒ String

Raise an exception if the provided path is invalid.

Parameters:

  • path (String) —

    The XenStore path to check.

Returns:

  • (String) —

    The valid path.



99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
 
# File 'lib/xsrb/utils.rb', line 99

def valid_path?(path)
  pathname = Pathname.new path
  max_len = pathname.absolute? ? 3072 : 2048

  if path.length > max_len
    raise XenStore::Exceptions::InvalidPath,
          "Path too long: #{path}"
  end

  unless @path_regex =~ path
    raise XenStore::Exceptions::InvalidPath,
          path.to_s
  end

  path
end

.valid_permissions?(perms) ⇒ Array

Check if every member of a list of permissions strings is valid.

Parameters:

  • perms (Array, String) —

    An Array of XenStore permissions specifications

Returns:

  • (Array) —

    The list of permissions.



133
134
135
136
137
138
139
140
141
 
# File 'lib/xsrb/utils.rb', line 133

def valid_permissions?(perms)
  perms = [perms] if perms.is_a? String
  perms.each do |perm|
    unless perm =~ @perms_regex
      raise XenStore::Exceptions::InvalidPermission,
            "Invalid permission string: #{perm}"
    end
  end
end

.valid_watch_path?(path) ⇒ String

Raise an exception if the provided XenStore watch path is invalid.

Parameters:

  • path (String) —

    The XenStore watch path to check.

Returns:

  • (String) —

    The valid path.



120
121
122
123
124
125
126
 
# File 'lib/xsrb/utils.rb', line 120

def valid_watch_path?(path)
  if path.starts_with?('@') && (@watch_path_regex !~ path)
    raise XenStore::Exceptions::InvalidPath, path.to_s
  end

  valid_path? path
end

.xenbus_path ⇒ String

Get the XenBus path on this system

Returns:

  • (String) —

    The path to the XenBus device



146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
 
# File 'lib/xsrb/utils.rb', line 146

def xenbus_path
  default = '/dev/xen/xenbus'
  host_os = RbConfig::CONFIG['host_os']

  case host_os
  when 'netbsd'
    '/kern/xen/xenbus'
  when 'linux'
    File.readable?('/dev/xen/xenbus') ? '/proc/xen/xenbus' : default
  when /mswin|windows/i
    raise NotImplementedError,
          "OS '#{RbConfig::CONFIG['host_os']}' is not supported"
  else
    default
  end
end