libs/uvl/luasrc/uvl.lua

   1 --[[
   2
   3 UCI Validation Layer - Main Library
   4 (c) 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
   5 (c) 2008 Steven Barth <steven@midlink.org>
   6
   7 Licensed under the Apache License, Version 2.0 (the "License");
   8 you may not use this file except in compliance with the License.
   9 You may obtain a copy of the License at
  10
  11                 http://www.apache.org/licenses/LICENSE-2.0
  12
  13 $Id$
  14
  15 ]]--
  16
  17
  18 --- UVL - UCI Validation Layer
  19 -- @class       module
  20 -- @cstyle      instance
  21
  22 local fs = require "luci.fs"
  23 local uci = require "luci.model.uci"
  24 local util = require "luci.util"
  25 local table = require "table"
  26 local string = require "string"
  27
  28 local require, pcall, ipairs, pairs = require, pcall, ipairs, pairs
  29 local type, error, tonumber, tostring = type, error, tonumber, tostring
  30 local unpack, loadfile = unpack, loadfile
  31
  32 module "luci.uvl"
  33
  34 local ERR = require "luci.uvl.errors"
  35 local datatypes = require "luci.uvl.datatypes"
  36 local validation = require "luci.uvl.validation"
  37 local dependencies = require "luci.uvl.dependencies"
  38
  39 local TYPE_SCHEME   = 0x00
  40 local TYPE_CONFIG   = 0x01
  41 local TYPE_SECTION  = 0x02
  42 local TYPE_OPTION   = 0x03
  43 local TYPE_ENUM     = 0x04
  44
  45 --- Boolean; default true;
  46 -- treat sections found in config but not in scheme as error
  47 STRICT_UNKNOWN_SECTIONS    = true
  48
  49 --- Boolean; default true;
  50 -- treat options found in config but not in scheme as error
  51 STRICT_UNKNOWN_OPTIONS     = true
  52
  53 --- Boolean; default true;
  54 -- treat failed external validators as error
  55 STRICT_EXTERNAL_VALIDATORS = true
  56
  57 --- Boolean; default true;
  58 -- treat list values stored as options like errors
  59 STRICT_LIST_TYPE           = true
  60
  61
  62 local default_schemedir = "/lib/uci/schema"
  63 local default_savedir = "/tmp/.uvl"
  64
  65
  66 --- Object constructor
  67 -- @class                       function
  68 -- @name                        UVL
  69 -- @param schemedir     Path to the scheme directory (optional)
  70 -- @return                      Instance object
  71 UVL = util.class()
  72
  73 function UVL.__init__( self, schemedir )
  74         self.schemedir  = schemedir or default_schemedir
  75         self.packages   = { }
  76         self.beenthere  = { }
  77         self.depseen    = { }
  78         self.uci                = uci
  79         self.err                = ERR
  80         self.dep                = dependencies
  81         self.datatypes  = datatypes
  82 end
  83
  84
  85 --- Parse given scheme and return the scheme tree.
  86 -- @param scheme        Name of the scheme to parse
  87 -- @return                      Table containing the parsed scheme or nil on error
  88 -- @return                      String containing the reason for errors (if any)
  89 function UVL.get_scheme( self, scheme )
  90         if not self.packages[scheme] then
  91                 local ok, err = self:read_scheme( scheme )
  92                 if not ok then
  93                         return nil, err
  94                 end
  95         end
  96         return self.packages[scheme], nil
  97 end
  98
  99 --- Validate given configuration, section or option.
 100 -- @param config        Name of the configuration to validate
 101 -- @param section       Name of the section to validate (optional)
 102 -- @param option        Name of the option to validate (optional)
 103 -- @return                      Boolean indicating whether the given config validates
 104 -- @return                      String containing the reason for errors (if any)
 105 function UVL.validate( self, config, section, option )
 106         if config and section and option then
 107                 return self:validate_option( config, section, option )
 108         elseif config and section then
 109                 return self:validate_section( config, section )
 110         elseif config then
 111                 return self:validate_config( config )
 112         end
 113 end
 114
 115 --- Validate given configuration.
 116 -- @param cfg   Name of the configuration to validate
 117 -- @return                      Boolean indicating whether the given config validates
 118 -- @return                      String containing the reason for errors (if any)
 119 function UVL.validate_config( self, cfg, uci )
 120
 121         if not self.packages[cfg] then
 122                 local ok, err = self:read_scheme(cfg)
 123                 if not ok then
 124                         return false, err
 125                 end
 126         end
 127
 128         local co = config( self, uci or cfg, uci and cfg )
 129         local sc = { }
 130
 131         self.beenthere = { }
 132         self.depseen   = { }
 133
 134         if not co:config() then
 135                 return false, co:errors()
 136         end
 137
 138         local function _uci_foreach( type, func )
 139                 for k, v in pairs(co:config()) do
 140                         if v['.type'] == type then
 141                                 sc[type] = sc[type] + 1
 142                                 local ok, err = func( k, v )
 143                                 if not ok then co:error(err) end
 144                         end
 145                 end
 146         end
 147
 148         for k, v in pairs( self.packages[cfg].sections ) do
 149                 sc[k] = 0
 150                 _uci_foreach( k,
 151                         function(s)
 152                                 return self:_validate_section( co:section(s) )
 153                         end
 154                 )
 155         end
 156
 157         if STRICT_UNKNOWN_SECTIONS then
 158                 for k, v in pairs(co:config()) do
 159                         local so = co:section(k)
 160                         if not self.beenthere[so:cid()] then
 161                                 co:error(ERR.SECT_UNKNOWN(so))
 162                         end
 163                 end
 164         end
 165
 166         for _, k in ipairs(util.keys(sc)) do
 167                 local so = co:section(k)
 168                 if so:scheme('required') and sc[k] == 0 then
 169                         co:error(ERR.SECT_REQUIRED(so))
 170                 elseif so:scheme('unique') and sc[k] > 1 then
 171                         co:error(ERR.SECT_UNIQUE(so))
 172                 end
 173         end
 174
 175         return co:ok(), co:errors()
 176 end
 177
 178 --- Validate given config section.
 179 -- @param config        Name of the configuration to validate
 180 -- @param section       Name of the section to validate
 181 -- @return                      Boolean indicating whether the given config validates
 182 -- @return                      String containing the reason for errors (if any)
 183 function UVL.validate_section( self, cfg, section, uci )
 184
 185         if not self.packages[cfg] then
 186                 local ok, err = self:read_scheme( cfg )
 187                 if not ok then
 188                         return false, err
 189                 end
 190         end
 191
 192         local co = config( self, uci or cfg, uci and cfg )
 193         local so = co:section( section )
 194
 195         self.beenthere = { }
 196         self.depseen   = { }
 197
 198         if not co:config() then
 199                 return false, co:errors()
 200         end
 201
 202         if so:config() then
 203                 return self:_validate_section( so )
 204         else
 205                 return false, ERR.SECT_NOTFOUND(so)
 206         end
 207 end
 208
 209 --- Validate given config option.
 210 -- @param config        Name of the configuration to validate
 211 -- @param section       Name of the section to validate
 212 -- @param option        Name of the option to validate
 213 -- @return                      Boolean indicating whether the given config validates
 214 -- @return                      String containing the reason for errors (if any)
 215 function UVL.validate_option( self, cfg, section, option, uci )
 216
 217         if not self.packages[cfg] then
 218                 local ok, err = self:read_scheme( cfg )
 219                 if not ok then
 220                         return false, err
 221                 end
 222         end
 223
 224         local co = config( self, uci or cfg, uci and cfg )
 225         local so = co:section( section )
 226         local oo = so:option( option )
 227
 228         if not co:config() then
 229                 return false, co:errors()
 230         end
 231
 232         if so:config() and oo:config() then
 233                 return self:_validate_option( oo )
 234         else
 235                 return false, ERR.OPT_NOTFOUND(oo)
 236         end
 237 end
 238
 239
 240 function UVL._validate_section( self, section )
 241
 242         self.beenthere[section:cid()] = true
 243
 244         if section:config() then
 245                 if section:scheme('named') == true and
 246                    section:config('.anonymous') == true
 247                 then
 248                         return false, ERR.SECT_NAMED(section)
 249                 end
 250
 251                 for _, v in ipairs(section:variables()) do
 252                         local ok, err = self:_validate_option( v )
 253                         if not ok and (
 254                                 v:scheme('required') or v:scheme('type') == "enum" or (
 255                                         not err:is(ERR.ERR_DEP_NOTEQUAL) and
 256                                         not err:is(ERR.ERR_DEP_NOVALUE)
 257                                 )
 258                         ) then
 259                                 section:error(err)
 260                         end
 261                 end
 262
 263                 local ok, err = dependencies.check( self, section )
 264                 if not ok then
 265                         section:error(err)
 266                 end
 267         else
 268                 return false, ERR.SECT_NOTFOUND(section)
 269         end
 270
 271         if STRICT_UNKNOWN_OPTIONS and not section:scheme('dynamic') then
 272                 for k, v in pairs(section:config()) do
 273                         local oo = section:option(k)
 274                         if k:sub(1,1) ~= "." and not self.beenthere[oo:cid()] then
 275                                 section:error(ERR.OPT_UNKNOWN(oo))
 276                         end
 277                 end
 278         end
 279
 280         return section:ok(), section:errors()
 281 end
 282
 283 function UVL._validate_option( self, option, nodeps )
 284
 285         self.beenthere[option:cid()] = true
 286
 287         if not option:scheme() and not option:parent():scheme('dynamic') then
 288                 if STRICT_UNKNOWN_OPTIONS then
 289                         return false, option:error(ERR.OPT_UNKNOWN(option))
 290                 else
 291                         return true
 292                 end
 293
 294         elseif option:scheme() then
 295                 if not nodeps then
 296                         local ok, err = dependencies.check( self, option )
 297                         if not ok then
 298                                 if not err:is_all(ERR.ERR_DEP_NOTEQUAL) and
 299                                    not err:is_all(ERR.ERR_DEP_NOVALUE)
 300                                 then
 301                                         option:error(err)
 302                                         return false, option:errors()
 303                                 else
 304                                         return true
 305                                 end
 306                         end
 307                 end
 308
 309                 if option:scheme('required') and not option:value() then
 310                         return false, option:error(ERR.OPT_REQUIRED(option))
 311
 312                 elseif option:value() then
 313                         local val = option:value()
 314
 315                         if option:scheme('type') == "reference" or
 316                            option:scheme('type') == "enum"
 317                         then
 318                                 local scheme_values = option:scheme('values') or { }
 319                                 local config_values = ( type(val) == "table" and val or { val } )
 320                                 for _, v in ipairs(config_values) do
 321                                         if not scheme_values[v] then
 322                                                 return false, option:error( ERR.OPT_BADVALUE(
 323                                                         option, { v, util.serialize_data(
 324                                                                 util.keys(scheme_values)
 325                                                         ) }
 326                                                 ) )
 327                                         end
 328                                 end
 329                         elseif option:scheme('type') == "list" then
 330                                 if type(val) ~= "table" and STRICT_LIST_TYPE then
 331                                         return false, option:error(ERR.OPT_NOTLIST(option))
 332                                 end
 333                         end
 334
 335                         if option:scheme('datatype') then
 336                                 local dt = option:scheme('datatype')
 337
 338                                 if self.datatypes[dt] then
 339                                         val = ( type(val) == "table" and val or { val } )
 340                                         for i, v in ipairs(val) do
 341                                                 if not self.datatypes[dt]( v ) then
 342                                                         return false, option:error(
 343                                                                 ERR.OPT_INVVALUE(option, { v, dt })
 344                                                         )
 345                                                 end
 346                                         end
 347                                 else
 348                                         return false, option:error(ERR.OPT_DATATYPE(option, dt))
 349                                 end
 350                         end
 351
 352                         val = ( type(val) == "table" and val or { val } )
 353                         for _, v in ipairs(val) do
 354                                 if option:scheme('minlength') then
 355                                         if #v < option:scheme('minlength') then
 356                                                 return false, option:error(ERR.OPT_RANGE(option))
 357                                         end
 358                                 end
 359
 360                                 if option:scheme('maxlength') then
 361                                         if #v > option:scheme('maxlength') then
 362                                                 return false, option:error(ERR.OPT_RANGE(option))
 363                                         end
 364                                 end
 365
 366                                 v = tonumber(v)
 367
 368                                 if option:scheme('minimum') then
 369                                         if not v or v < option:scheme('minimum') then
 370                                                 return false, option:error(ERR.OPT_RANGE(option))
 371                                         end
 372                                 end
 373
 374                                 if option:scheme('maximum') then
 375                                         if not v or v > option:scheme('maximum') then
 376                                                 return false, option:error(ERR.OPT_RANGE(option))
 377                                         end
 378                                 end
 379                         end
 380                 end
 381
 382                 local ok, err = validation.check( self, option )
 383                 if not ok and STRICT_EXTERNAL_VALIDATORS then
 384                         return false, option:error(err)
 385                 end
 386         end
 387
 388         return option:ok(), option:errors()
 389 end
 390
 391 --- Find all parts of given scheme and construct validation tree.
 392 -- This is normally done on demand, so you don't have to call this function
 393 -- by yourself.
 394 -- @param shm   Name of the scheme to parse
 395 -- @param alias         Create an alias for the loaded scheme
 396 function UVL.read_scheme( self, shm, alias )
 397
 398         local so = scheme( self, shm )
 399         local bc = "%s/bytecode/%s.lua" %{ self.schemedir, shm }
 400
 401         if not fs.access(bc) then
 402                 local files = fs.glob(self.schemedir .. '/*/' .. shm)
 403
 404                 if files then
 405                         local ok, err
 406                         for i, file in ipairs( files ) do
 407                                 if not fs.access(file) then
 408                                         return false, so:error(ERR.SME_READ(so,file))
 409                                 end
 410
 411                                 local uci = uci.cursor( fs.dirname(file), default_savedir )
 412
 413                                 local sname = fs.basename(file)
 414                                 local sd, err = uci:load( sname )
 415
 416                                 if not sd then
 417                                         return false, ERR.UCILOAD(so, err)
 418                                 end
 419
 420                                 ok, err = pcall(function()
 421                                         uci:foreach(sname, "package", function(s)
 422                                                 self:_parse_package(so, s[".name"], s)
 423                                         end)
 424                                         uci:foreach(sname, "section", function(s)
 425                                                 self:_parse_section(so, s[".name"], s)
 426                                         end)
 427                                         uci:foreach(sname, "variable", function(s)
 428                                                 self:_parse_var(so, s[".name"], s)
 429                                         end)
 430                                         uci:foreach(sname, "enum", function(s)
 431                                                 self:_parse_enum(so, s[".name"], s)
 432                                         end)
 433
 434                                 end)
 435                         end
 436
 437                         if ok and alias then self.packages[alias] = self.packages[shm] end
 438                         return ok and self, err
 439                 else
 440                         return false, so:error(ERR.SME_FIND(so, self.schemedir))
 441                 end
 442         else
 443                 local sc = loadfile(bc)
 444                 if sc then
 445                         self.packages[shm] = sc()
 446                         return true
 447                 else
 448                         return false, so:error(ERR.SME_READ(so,bc))
 449                 end
 450         end
 451 end
 452
 453 -- helper function to check for required fields
 454 local function _req( t, n, c, r )
 455         for i, v in ipairs(r) do
 456                 if not c[v] then
 457                         local p, o = scheme:sid(), nil
 458
 459                         if t == TYPE_SECTION then
 460                                 o = section( scheme, nil, p, n )
 461                         elseif t == TYPE_OPTION then
 462                                 o = option( scheme, nil, p, '(nil)', n )
 463                         elseif t == TYPE_ENUM then
 464                                 o = enum( scheme, nil, p, '(nil)', '(nil)', n )
 465                         end
 466
 467                         return false, ERR.SME_REQFLD(o,v)
 468                 end
 469         end
 470         return true
 471 end
 472
 473 -- helper function to validate references
 474 local function _ref( c, t )
 475         local r, k, n = {}
 476         if c == TYPE_SECTION then
 477                 k = "package"
 478                 n = 1
 479         elseif c == TYPE_OPTION then
 480                 k = "section"
 481                 n = 2
 482         elseif c == TYPE_ENUM then
 483                 k = "variable"
 484                 n = 3
 485         end
 486
 487         for o in t[k]:gmatch("[^.]+") do
 488                 r[#r+1] = o
 489         end
 490         r[1] = ( #r[1] > 0 and r[1] or scheme:sid() )
 491
 492         if #r ~= n then
 493                 return false, ERR.SME_BADREF(scheme, k)
 494         end
 495
 496         return r
 497 end
 498
 499 -- helper function to read bools
 500 local function _bool( v )
 501         return ( v == "true" or v == "yes" or v == "on" or v == "1" )
 502 end
 503
 504 -- Step 0: get package meta information
 505 function UVL._parse_package(self, scheme, k, v)
 506         local sid = scheme:sid()
 507         local pkg = self.packages[sid] or {
 508                 ["name"]      = sid;
 509                 ["sections"]  = { };
 510                 ["variables"] = { };
 511         }
 512
 513         pkg.title = v.title
 514         pkg.description = v.description
 515
 516         self.packages[sid] = pkg
 517 end
 518
 519 -- Step 1: get all sections
 520 function UVL._parse_section(self, scheme, k, v)
 521         local ok, err = _req( TYPE_SECTION, k, v, { "name", "package" } )
 522         if err then error(scheme:error(err)) end
 523
 524         local r, err = _ref( TYPE_SECTION, v )
 525         if err then error(scheme:error(err)) end
 526
 527         local p = self.packages[r[1]] or {
 528                 ["name"]      = r[1];
 529                 ["sections"]  = { };
 530                 ["variables"] = { };
 531         }
 532         p.sections[v.name]  = p.sections[v.name]  or { }
 533         p.variables[v.name] = p.variables[v.name] or { }
 534         self.packages[r[1]] = p
 535
 536         local s  = p.sections[v.name]
 537         local so = scheme:section(v.name)
 538
 539         for k, v2 in pairs(v) do
 540                 if k ~= "name" and k ~= "package" and k:sub(1,1) ~= "." then
 541                         if k == "depends" then
 542                                 s.depends = self:_read_dependency( v2, s.depends )
 543                                 if not s.depends then
 544                                         return false, scheme:error(
 545                                                 ERR.SME_BADDEP(so, util.serialize_data(s.depends))
 546                                         )
 547                                 end
 548                         elseif k == "dynamic" or k == "unique" or
 549                                k == "required" or k == "named"
 550                         then
 551                                 s[k] = _bool(v2)
 552                         else
 553                                 s[k] = v2
 554                         end
 555                 end
 556         end
 557
 558         s.dynamic  = s.dynamic  or false
 559         s.unique   = s.unique   or false
 560         s.required = s.required or false
 561         s.named    = s.named    or false
 562 end
 563
 564 -- Step 2: get all variables
 565 function UVL._parse_var(self, scheme, k, v)
 566         local ok, err = _req( TYPE_OPTION, k, v, { "name", "section" } )
 567         if err then error(scheme:error(err)) end
 568
 569         local r, err = _ref( TYPE_OPTION, v )
 570         if err then error(scheme:error(err)) end
 571
 572         local p = self.packages[r[1]]
 573         if not p then
 574                 error(scheme:error(
 575                         ERR.SME_VBADPACK({scheme:sid(), '', v.name}, r[1])
 576                 ))
 577         end
 578
 579         local s = p.variables[r[2]]
 580         if not s then
 581                 error(scheme:error(
 582                         ERR.SME_VBADSECT({scheme:sid(), '', v.name}, r[2])
 583                 ))
 584         end
 585
 586         s[v.name] = s[v.name] or { }
 587
 588         local t  = s[v.name]
 589         local so = scheme:section(r[2])
 590         local to = so:option(v.name)
 591
 592         for k, v2 in pairs(v) do
 593                 if k ~= "name" and k ~= "section" and k:sub(1,1) ~= "." then
 594                         if k == "depends" then
 595                                 t.depends = self:_read_dependency( v2, t.depends )
 596                                 if not t.depends then
 597                                         error(scheme:error(so:error(
 598                                                 ERR.SME_BADDEP(to, util.serialize_data(v2))
 599                                         )))
 600                                 end
 601                         elseif k == "validator" then
 602                                 t.validators = self:_read_validator( v2, t.validators )
 603                                 if not t.validators then
 604                                         error(scheme:error(so:error(
 605                                                 ERR.SME_BADVAL(to, util.serialize_data(v2))
 606                                         )))
 607                                 end
 608                         elseif k == "valueof" then
 609                                 local values, err = self:_read_reference( v2 )
 610                                 if err then
 611                                         error(scheme:error(so:error(
 612                                                 ERR.REFERENCE(to, util.serialize_data(v2)):child(err)
 613                                         )))
 614                                 end
 615                                 t.type   = "reference"
 616                                 t.values = values
 617                                 t.valueof = type(v2) == "table" and v2 or {v2}
 618                         elseif k == "required" then
 619                                 t[k] = _bool(v2)
 620                         elseif k == "minlength" or k == "maxlength" or
 621                    k == "minimum" or k == "maximum"
 622             then
 623                                 t[k] = tonumber(v2)
 624                         else
 625                                 t[k] = t[k] or v2
 626                         end
 627                 end
 628         end
 629
 630         t.type     = t.type     or "variable"
 631         t.datatype = t.datatype or "string"
 632         t.required = t.required or false
 633 end
 634
 635 -- Step 3: get all enums
 636 function UVL._parse_enum(self, scheme, k, v)
 637         local ok, err = _req( TYPE_ENUM, k, v, { "value", "variable" } )
 638         if err then error(scheme:error(err)) end
 639
 640         local r, err = _ref( TYPE_ENUM, v )
 641         if err then error(scheme:error(err)) end
 642
 643         local p = self.packages[r[1]]
 644         if not p then
 645                 error(scheme:error(
 646                         ERR.SME_EBADPACK({scheme:sid(), '', '', v.value}, r[1])
 647                 ))
 648         end
 649
 650         local s = p.variables[r[2]]
 651         if not s then
 652                 error(scheme:error(
 653                         ERR.SME_EBADSECT({scheme:sid(), '', '', v.value}, r[2])
 654                 ))
 655         end
 656
 657         local t = s[r[3]]
 658         if not t then
 659                 error(scheme:error(
 660                         ERR.SME_EBADOPT({scheme:sid(), '', '', v.value}, r[3])
 661                 ))
 662         end
 663
 664
 665         local so = scheme:section(r[2])
 666         local oo = so:option(r[3])
 667         local eo = oo:enum(v.value)
 668
 669         if t.type ~= "enum" and t.type ~= "reference" then
 670                 error(scheme:error(ERR.SME_EBADTYPE(eo)))
 671         end
 672
 673         if not t.values then
 674                 t.values = { [v.value] = v.title or v.value }
 675                 t.valuelist = { {value = v.value, title = v.title} }
 676         else
 677                 t.values[v.value] = v.title or v.value
 678                 t.valuelist[#t.valuelist + 1] = {value = v.value, title = v.title}
 679         end
 680
 681         if not t.enum_depends then
 682                 t.enum_depends = { }
 683         end
 684
 685         if v.default then
 686                 if t.default then
 687                         error(scheme:error(ERR.SME_EBADDEF(eo)))
 688                 end
 689                 t.default = v.value
 690         end
 691
 692         if v.depends then
 693                 t.enum_depends[v.value] = self:_read_dependency(
 694                         v.depends, t.enum_depends[v.value]
 695                 )
 696
 697                 if not t.enum_depends[v.value] then
 698                         error(scheme:error(so:error(oo:error(
 699                                 ERR.SME_BADDEP(eo, util.serialize_data(v.depends))
 700                         ))))
 701                 end
 702         end
 703 end
 704
 705 -- Read a dependency specification
 706 function UVL._read_dependency( self, values, deps )
 707         local expr = "%$?[%w_]+"
 708         if values then
 709                 values = ( type(values) == "table" and values or { values } )
 710                 for _, value in ipairs(values) do
 711                         local condition = { }
 712                         for val in value:gmatch("[^,]+") do
 713                                 local k, e, v = val:match("%s*([%w$_.]+)%s*(=?)%s*(.*)")
 714
 715                                 if k and (
 716                                         k:match("^"..expr.."%."..expr.."%."..expr.."$") or
 717                                         k:match("^"..expr.."%."..expr.."$") or
 718                                         k:match("^"..expr.."$")
 719                                 ) then
 720                                         condition[k] = (e == '=') and v or true
 721                                 else
 722                                         return nil
 723                                 end
 724                         end
 725
 726                         if not deps then
 727                                 deps = { condition }
 728                         else
 729                                 deps[#deps+1] = condition
 730                         end
 731                 end
 732         end
 733
 734         return deps
 735 end
 736
 737 -- Read a validator specification
 738 function UVL._read_validator( self, values, validators )
 739         if values then
 740                 values = ( type(values) == "table" and values or { values } )
 741                 for _, value in ipairs(values) do
 742                         local validator
 743
 744                         if value:match("^exec:") then
 745                                 validator = value:gsub("^exec:","")
 746                         elseif value:match("^lua:") then
 747                                 validator = self:_resolve_function( (value:gsub("^lua:","") ) )
 748                         elseif value:match("^regexp:") then
 749                                 local pattern = value:gsub("^regexp:","")
 750                                 validator = function( type, dtype, pack, sect, optn, ... )
 751                                         local values = { ... }
 752                                         for _, v in ipairs(values) do
 753                                                 local ok, match =
 754                                                         pcall( string.match, v, pattern )
 755
 756                                                 if not ok then
 757                                                         return false, match
 758                                                 elseif not match then
 759                                                         return false,
 760                                                                 'Value "%s" does not match pattern "%s"' % {
 761                                                                         v, pattern
 762                                                                 }
 763                                                 end
 764                                         end
 765                                         return true
 766                                 end
 767                         end
 768
 769                         if validator then
 770                                 if not validators then
 771                                         validators = { validator }
 772                                 else
 773                                         validators[#validators+1] = validator
 774                                 end
 775                         else
 776                                 return nil
 777                         end
 778                 end
 779
 780                 return validators
 781         end
 782 end
 783
 784 -- Read a reference specification (XXX: We should validate external configs too...)
 785 function UVL._read_reference( self, values )
 786         local val = { }
 787         values = ( type(values) == "table" and values or { values } )
 788
 789         for _, value in ipairs(values) do
 790                 local ref = util.split(value, ".")
 791
 792                 if #ref == 2 or #ref == 3 then
 793                         local co = config( self, ref[1] )
 794                         if not co:config() then return false, co:errors() end
 795
 796                         for k, v in pairs(co:config()) do
 797                                 if v['.type'] == ref[2] then
 798                                         if #ref == 2 then
 799                                                 if v['.anonymous'] == true then
 800                                                         return false, ERR.SME_INVREF('', value)
 801                                                 end
 802                                                 val[k] = k      -- XXX: title/description would be nice
 803                                         elseif v[ref[3]] then
 804                                                 val[v[ref[3]]] = v[ref[3]]  -- XXX: dito
 805                                         end
 806                                 end
 807                         end
 808                 else
 809                         return false, ERR.SME_BADREF('', value)
 810                 end
 811         end
 812
 813         return val, nil
 814 end
 815
 816 -- Resolve given path
 817 function UVL._resolve_function( self, value )
 818         local path = util.split(value, ".")
 819
 820         for i=1, #path-1 do
 821                 local stat, mod = pcall(
 822                         require, table.concat(path, ".", 1, i)
 823                 )
 824
 825                 if stat and mod then
 826                         for j=i+1, #path-1 do
 827                                 if not type(mod) == "table" then
 828                                         break
 829                                 end
 830                                 mod = mod[path[j]]
 831                                 if not mod then
 832                                         break
 833                                 end
 834                         end
 835                         mod = type(mod) == "table" and mod[path[#path]] or nil
 836                         if type(mod) == "function" then
 837                                 return mod
 838                         end
 839                 end
 840         end
 841 end
 842
 843
 844 --- Object representation of an uvl item - base class.
 845 uvlitem = util.class()
 846
 847 function uvlitem.cid(self)
 848         if #self.cref == 1 then
 849                 return self.cref[1]
 850         else
 851                 local r = { unpack(self.cref) }
 852                 local c = self.c
 853                 if c and c[r[2]] and c[r[2]]['.anonymous'] and c[r[2]]['.index'] then
 854                         r[2] = '@' .. c[r[2]]['.type'] ..
 855                                    '[' .. tostring(c[r[2]]['.index']) .. ']'
 856                 end
 857                 return table.concat( r, '.' )
 858         end
 859 end
 860
 861 function uvlitem.sid(self)
 862         return table.concat( self.sref, '.' )
 863 end
 864
 865 function uvlitem.scheme(self, opt)
 866         local s = self.s and self.s.packages
 867         s = s      and s[self.sref[1]]
 868         if #self.sref == 4 or #self.sref == 3 then
 869                 s = s      and s.variables
 870                 s = s      and s[self.sref[2]]
 871                 s = s      and s[self.sref[3]]
 872         elseif #self.sref == 2 then
 873                 s = s      and s.sections
 874                 s = s      and s[self.sref[2]]
 875         end
 876
 877         if s and opt then
 878                 return s[opt]
 879         elseif s then
 880                 return s
 881         end
 882 end
 883
 884 function uvlitem.config(self, opt)
 885         local c = self.c
 886
 887         if #self.cref >= 2 and #self.cref <= 4 then
 888                 c = c and self.c[self.cref[2]] or nil
 889                 if #self.cref >= 3 then
 890                         c = c and c[self.cref[3]] or nil
 891                 end
 892         end
 893
 894         if c and opt then
 895                 return c[opt]
 896         elseif c then
 897                 return c
 898         end
 899 end
 900
 901 function uvlitem.title(self)
 902         return self:scheme() and self:scheme('title') or
 903                 self.cref[3] or self.cref[2] or self.cref[1]
 904 end
 905
 906 function uvlitem.type(self)
 907         if self.t == TYPE_CONFIG then
 908                 return 'config'
 909         elseif self.t == TYPE_SECTION then
 910                 return 'section'
 911         elseif self.t == TYPE_OPTION then
 912                 return 'option'
 913         elseif self.t == TYPE_ENUM then
 914                 return 'enum'
 915         end
 916 end
 917
 918 function uvlitem.error(self, ...)
 919         if not self.e then
 920                 local errconst = { ERR.CONFIG, ERR.SECTION, ERR.OPTION, ERR.OPTION }
 921                 self.e = errconst[#self.cref]( self )
 922         end
 923
 924         return self.e:child( ... )
 925 end
 926
 927 function uvlitem.errors(self)
 928         return self.e
 929 end
 930
 931 function uvlitem.ok(self)
 932         return not self:errors()
 933 end
 934
 935 function uvlitem.parent(self)
 936         if self.p then
 937                 return self.p
 938         elseif #self.cref == 3 or #self.cref == 4 then
 939                 return section( self.s, self.c, self.cref[1], self.cref[2] )
 940         elseif #self.cref == 2 then
 941                 return config( self.s, self.c, self.cref[1] )
 942         else
 943                 return nil
 944         end
 945 end
 946
 947 function uvlitem._loadconf(self, co, c)
 948         co = co or self._configcache
 949         if not co then
 950                 local err
 951                 co, err = uci.cursor():get_all(c)
 952
 953                 if err then
 954                         self:error(ERR.UCILOAD(self, err))
 955                 end
 956
 957                 self._configcache = co
 958         end
 959         return co
 960 end
 961
 962
 963 --- Object representation of a scheme.
 964 -- @class       scheme
 965 -- @cstyle      instance
 966 -- @name        luci.uvl.scheme
 967
 968 --- Scheme instance constructor.
 969 -- @class                       function
 970 -- @name                        scheme
 971 -- @param scheme        Scheme instance
 972 -- @param co            Configuration data
 973 -- @param c                     Configuration name
 974 -- @return                      Config instance
 975 scheme = util.class(uvlitem)
 976
 977 function scheme.__init__(self, scheme, co, c)
 978         if not c then
 979                 c, co = co, nil
 980         end
 981
 982         self.cref = { c }
 983         self.sref = { c }
 984         self.c    = self:_loadconf(co, c)
 985         self.s    = scheme
 986         self.t    = TYPE_SCHEME
 987 end
 988
 989 --- Add an error to scheme.
 990 -- @return      Scheme error context
 991 function scheme.error(self, ...)
 992         if not self.e then self.e = ERR.SCHEME( self ) end
 993         return self.e:child( ... )
 994 end
 995
 996 --- Get an associated config object.
 997 -- @return      Config instance
 998 function scheme.config(self)
 999         local co = config( self.s, self.cref[1] )
1000               co.p = self
1001
1002         return co
1003 end
1004
1005 --- Get all section objects associated with this scheme.
1006 -- @return      Table containing all associated luci.uvl.section instances
1007 function scheme.sections(self)
1008         local v = { }
1009         if self.s.packages[self.sref[1]].sections then
1010                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
1011                         v[#v+1] = option(
1012                                 self.s, self.c, self.cref[1], self.cref[2], o
1013                         )
1014                 end
1015         end
1016         return v
1017 end
1018
1019 --- Get an associated section object.
1020 -- @param s     Section to select
1021 -- @return      Section instance
1022 function scheme.section(self, s)
1023         local so = section( self.s, self.c, self.cref[1], s )
1024               so.p = self
1025
1026         return so
1027 end
1028
1029
1030 --- Object representation of a config.
1031 -- @class       config
1032 -- @cstyle      instance
1033 -- @name        luci.uvl.config
1034
1035 --- Config instance constructor.
1036 -- @class                       function
1037 -- @name                        config
1038 -- @param scheme        Scheme instance
1039 -- @param co            Configuration data
1040 -- @param c                     Configuration name
1041 -- @return                      Config instance
1042 config = util.class(uvlitem)
1043
1044 function config.__init__(self, scheme, co, c)
1045         if not c then
1046                 c, co = co, nil
1047         end
1048
1049         self.cref = { c }
1050         self.sref = { c }
1051         self.c    = self:_loadconf(co, c)
1052         self.s    = scheme
1053         self.t    = TYPE_CONFIG
1054 end
1055
1056 --- Get all section objects associated with this config.
1057 -- @return      Table containing all associated luci.uvl.section instances
1058 function config.sections(self)
1059         local v = { }
1060         if self.s.packages[self.sref[1]].sections then
1061                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
1062                         v[#v+1] = option(
1063                                 self.s, self.c, self.cref[1], self.cref[2], o
1064                         )
1065                 end
1066         end
1067         return v
1068 end
1069
1070 --- Get an associated section object.
1071 -- @param s     Section to select
1072 -- @return      Section instance
1073 function config.section(self, s)
1074         local so = section( self.s, self.c, self.cref[1], s )
1075               so.p = self
1076
1077         return so
1078 end
1079
1080
1081 --- Object representation of a scheme/config section.
1082 -- @class       module
1083 -- @cstyle      instance
1084 -- @name        luci.uvl.section
1085
1086 --- Section instance constructor.
1087 -- @class                       function
1088 -- @name                        section
1089 -- @param scheme        Scheme instance
1090 -- @param co            Configuration data
1091 -- @param c                     Configuration name
1092 -- @param s                     Section name
1093 -- @return                      Section instance
1094 section = util.class(uvlitem)
1095
1096 function section.__init__(self, scheme, co, c, s)
1097         self.cref = { c, s }
1098         self.sref = { c, co and co[s] and co[s]['.type'] or s }
1099         self.c    = self:_loadconf(co, c)
1100         self.s    = scheme
1101         self.t    = TYPE_SECTION
1102 end
1103
1104 --- Get all option objects associated with this section.
1105 -- @return      Table containing all associated luci.uvl.option instances
1106 function section.variables(self)
1107         local v = { }
1108         if self.s.packages[self.sref[1]].variables[self.sref[2]] then
1109                 for o, _ in pairs(
1110                         self.s.packages[self.sref[1]].variables[self.sref[2]]
1111                 ) do
1112                         v[#v+1] = option(
1113                                 self.s, self.c, self.cref[1], self.cref[2], o
1114                         )
1115                 end
1116         end
1117         return v
1118 end
1119
1120 --- Get an associated option object.
1121 -- @param o     Option to select
1122 -- @return      Option instance
1123 function section.option(self, o)
1124         local oo = option( self.s, self.c, self.cref[1], self.cref[2], o )
1125               oo.p = self
1126
1127         return oo
1128 end
1129
1130
1131 --- Object representation of a scheme/config option.
1132 -- @class       module
1133 -- @cstyle      instance
1134 -- @name        luci.uvl.option
1135
1136 --- Section instance constructor.
1137 -- @class                       function
1138 -- @name                        option
1139 -- @param scheme        Scheme instance
1140 -- @param co            Configuration data
1141 -- @param c                     Configuration name
1142 -- @param s                     Section name
1143 -- @param o                     Option name
1144 -- @return                      Option instance
1145 option = util.class(uvlitem)
1146
1147 function option.__init__(self, scheme, co, c, s, o)
1148         self.cref = { c, s, o }
1149         self.sref = { c, co and co[s] and co[s]['.type'] or s, o }
1150         self.c    = self:_loadconf(co, c)
1151         self.s    = scheme
1152         self.t    = TYPE_OPTION
1153 end
1154
1155 --- Get the value of this option.
1156 -- @return      The associated configuration value
1157 function option.value(self)
1158         local v = self:config() or self:scheme('default')
1159         if v and self:scheme('multival') then
1160                 v = util.split( v, "%s+", nil, true )
1161         end
1162         return v
1163 end
1164
1165 --- Get the associated section information in scheme.
1166 -- @return      Table containing the scheme properties
1167 function option.section(self)
1168         return self.s.packages[self.sref[1]].sections[self.sref[2]]
1169 end
1170
1171 --- Construct an enum object instance from given or default value.
1172 -- @param v     Value to select
1173 -- @return      Enum instance for selected value
1174 function option.enum(self, val)
1175         return enum(
1176                 self.s, self.c,
1177                 self.cref[1], self.cref[2], self.cref[3],
1178                 val or self:value()
1179         )
1180 end
1181
1182
1183 --- Object representation of a enum value.
1184 -- @class       module
1185 -- @cstyle      instance
1186 -- @name        luci.uvl.enum
1187
1188 --- Section instance constructor.
1189 -- @class                       function
1190 -- @name                        enum
1191 -- @param scheme        Scheme instance
1192 -- @param co            Configuration data
1193 -- @param c                     Configuration name
1194 -- @param s                     Section name
1195 -- @param o                     Enum name
1196 -- @param v                     Enum value
1197 -- @return                      Enum value instance
1198 enum = util.class(option)
1199
1200 function enum.__init__(self, scheme, co, c, s, o, v)
1201         self.cref = { c, s, o, v }
1202         self.sref = { c, co and co[s] and co[s]['.type'] or s, o, v }
1203         self.c    = self:_loadconf(co, c)
1204         self.s    = scheme
1205         self.t    = TYPE_ENUM
1206 end