git.r.bdr.sh - rbdr/mobius/blob - hotline/transaction_handlers.go

   1 package hotline
   2
   3 import (
   4         "bytes"
   5         "encoding/binary"
   6         "errors"
   7         "fmt"
   8         "gopkg.in/yaml.v3"
   9         "math/big"
  10         "os"
  11         "path"
  12         "path/filepath"
  13         "sort"
  14         "strings"
  15         "time"
  16 )
  17
  18 type TransactionType struct {
  19         Handler        func(*ClientConn, *Transaction) ([]Transaction, error) // function for handling the transaction type
  20         Name           string                                                 // Name of transaction as it will appear in logging
  21         RequiredFields []requiredField
  22 }
  23
  24 var TransactionHandlers = map[uint16]TransactionType{
  25         // Server initiated
  26         tranChatMsg: {
  27                 Name: "tranChatMsg",
  28         },
  29         // Server initiated
  30         tranNotifyChangeUser: {
  31                 Name: "tranNotifyChangeUser",
  32         },
  33         tranError: {
  34                 Name: "tranError",
  35         },
  36         tranShowAgreement: {
  37                 Name: "tranShowAgreement",
  38         },
  39         tranUserAccess: {
  40                 Name: "tranUserAccess",
  41         },
  42         tranNotifyDeleteUser: {
  43                 Name: "tranNotifyDeleteUser",
  44         },
  45         tranAgreed: {
  46                 Name:    "tranAgreed",
  47                 Handler: HandleTranAgreed,
  48         },
  49         tranChatSend: {
  50                 Name:    "tranChatSend",
  51                 Handler: HandleChatSend,
  52                 RequiredFields: []requiredField{
  53                         {
  54                                 ID:     fieldData,
  55                                 minLen: 0,
  56                         },
  57                 },
  58         },
  59         tranDelNewsArt: {
  60                 Name:    "tranDelNewsArt",
  61                 Handler: HandleDelNewsArt,
  62         },
  63         tranDelNewsItem: {
  64                 Name:    "tranDelNewsItem",
  65                 Handler: HandleDelNewsItem,
  66         },
  67         tranDeleteFile: {
  68                 Name:    "tranDeleteFile",
  69                 Handler: HandleDeleteFile,
  70         },
  71         tranDeleteUser: {
  72                 Name:    "tranDeleteUser",
  73                 Handler: HandleDeleteUser,
  74         },
  75         tranDisconnectUser: {
  76                 Name:    "tranDisconnectUser",
  77                 Handler: HandleDisconnectUser,
  78         },
  79         tranDownloadFile: {
  80                 Name:    "tranDownloadFile",
  81                 Handler: HandleDownloadFile,
  82         },
  83         tranDownloadFldr: {
  84                 Name:    "tranDownloadFldr",
  85                 Handler: HandleDownloadFolder,
  86         },
  87         tranGetClientInfoText: {
  88                 Name:    "tranGetClientInfoText",
  89                 Handler: HandleGetClientInfoText,
  90         },
  91         tranGetFileInfo: {
  92                 Name:    "tranGetFileInfo",
  93                 Handler: HandleGetFileInfo,
  94         },
  95         tranGetFileNameList: {
  96                 Name:    "tranGetFileNameList",
  97                 Handler: HandleGetFileNameList,
  98         },
  99         tranGetMsgs: {
 100                 Name:    "tranGetMsgs",
 101                 Handler: HandleGetMsgs,
 102         },
 103         tranGetNewsArtData: {
 104                 Name:    "tranGetNewsArtData",
 105                 Handler: HandleGetNewsArtData,
 106         },
 107         tranGetNewsArtNameList: {
 108                 Name:    "tranGetNewsArtNameList",
 109                 Handler: HandleGetNewsArtNameList,
 110         },
 111         tranGetNewsCatNameList: {
 112                 Name:    "tranGetNewsCatNameList",
 113                 Handler: HandleGetNewsCatNameList,
 114         },
 115         tranGetUser: {
 116                 Name:    "tranGetUser",
 117                 Handler: HandleGetUser,
 118         },
 119         tranGetUserNameList: {
 120                 Name:    "tranHandleGetUserNameList",
 121                 Handler: HandleGetUserNameList,
 122         },
 123         tranInviteNewChat: {
 124                 Name:    "tranInviteNewChat",
 125                 Handler: HandleInviteNewChat,
 126         },
 127         tranInviteToChat: {
 128                 Name:    "tranInviteToChat",
 129                 Handler: HandleInviteToChat,
 130         },
 131         tranJoinChat: {
 132                 Name:    "tranJoinChat",
 133                 Handler: HandleJoinChat,
 134         },
 135         tranKeepAlive: {
 136                 Name:    "tranKeepAlive",
 137                 Handler: HandleKeepAlive,
 138         },
 139         tranLeaveChat: {
 140                 Name:    "tranJoinChat",
 141                 Handler: HandleLeaveChat,
 142         },
 143         tranListUsers: {
 144                 Name:    "tranListUsers",
 145                 Handler: HandleListUsers,
 146         },
 147         tranMoveFile: {
 148                 Name:    "tranMoveFile",
 149                 Handler: HandleMoveFile,
 150         },
 151         tranNewFolder: {
 152                 Name:    "tranNewFolder",
 153                 Handler: HandleNewFolder,
 154         },
 155         tranNewNewsCat: {
 156                 Name:    "tranNewNewsCat",
 157                 Handler: HandleNewNewsCat,
 158         },
 159         tranNewNewsFldr: {
 160                 Name:    "tranNewNewsFldr",
 161                 Handler: HandleNewNewsFldr,
 162         },
 163         tranNewUser: {
 164                 Name:    "tranNewUser",
 165                 Handler: HandleNewUser,
 166         },
 167         tranUpdateUser: {
 168                 Name:    "tranUpdateUser",
 169                 Handler: HandleUpdateUser,
 170         },
 171         tranOldPostNews: {
 172                 Name:    "tranOldPostNews",
 173                 Handler: HandleTranOldPostNews,
 174         },
 175         tranPostNewsArt: {
 176                 Name:    "tranPostNewsArt",
 177                 Handler: HandlePostNewsArt,
 178         },
 179         tranRejectChatInvite: {
 180                 Name:    "tranRejectChatInvite",
 181                 Handler: HandleRejectChatInvite,
 182         },
 183         tranSendInstantMsg: {
 184                 Name:    "tranSendInstantMsg",
 185                 Handler: HandleSendInstantMsg,
 186                 RequiredFields: []requiredField{
 187                         {
 188                                 ID:     fieldData,
 189                                 minLen: 0,
 190                         },
 191                         {
 192                                 ID: fieldUserID,
 193                         },
 194                 },
 195         },
 196         tranSetChatSubject: {
 197                 Name:    "tranSetChatSubject",
 198                 Handler: HandleSetChatSubject,
 199         },
 200         tranMakeFileAlias: {
 201                 Name:    "tranMakeFileAlias",
 202                 Handler: HandleMakeAlias,
 203                 RequiredFields: []requiredField{
 204                         {ID: fieldFileName, minLen: 1},
 205                         {ID: fieldFilePath, minLen: 1},
 206                         {ID: fieldFileNewPath, minLen: 1},
 207                 },
 208         },
 209         tranSetClientUserInfo: {
 210                 Name:    "tranSetClientUserInfo",
 211                 Handler: HandleSetClientUserInfo,
 212         },
 213         tranSetFileInfo: {
 214                 Name:    "tranSetFileInfo",
 215                 Handler: HandleSetFileInfo,
 216         },
 217         tranSetUser: {
 218                 Name:    "tranSetUser",
 219                 Handler: HandleSetUser,
 220         },
 221         tranUploadFile: {
 222                 Name:    "tranUploadFile",
 223                 Handler: HandleUploadFile,
 224         },
 225         tranUploadFldr: {
 226                 Name:    "tranUploadFldr",
 227                 Handler: HandleUploadFolder,
 228         },
 229         tranUserBroadcast: {
 230                 Name:    "tranUserBroadcast",
 231                 Handler: HandleUserBroadcast,
 232         },
 233         tranDownloadBanner: {
 234                 Name:    "tranDownloadBanner",
 235                 Handler: HandleDownloadBanner,
 236         },
 237 }
 238
 239 func HandleChatSend(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 240         if !cc.Authorize(accessSendChat) {
 241                 res = append(res, cc.NewErrReply(t, "You are not allowed to participate in chat."))
 242                 return res, err
 243         }
 244
 245         // Truncate long usernames
 246         trunc := fmt.Sprintf("%13s", cc.UserName)
 247         formattedMsg := fmt.Sprintf("\r%.14s:  %s", trunc, t.GetField(fieldData).Data)
 248
 249         // By holding the option key, Hotline chat allows users to send /me formatted messages like:
 250         // *** Halcyon does stuff
 251         // This is indicated by the presence of the optional field fieldChatOptions set to a value of 1.
 252         // Most clients do not send this option for normal chat messages.
 253         if t.GetField(fieldChatOptions).Data != nil && bytes.Equal(t.GetField(fieldChatOptions).Data, []byte{0, 1}) {
 254                 formattedMsg = fmt.Sprintf("\r*** %s %s", cc.UserName, t.GetField(fieldData).Data)
 255         }
 256
 257         // The ChatID field is used to identify messages as belonging to a private chat.
 258         // All clients *except* Frogblast omit this field for public chat, but Frogblast sends a value of 00 00 00 00.
 259         chatID := t.GetField(fieldChatID).Data
 260         if chatID != nil && !bytes.Equal([]byte{0, 0, 0, 0}, chatID) {
 261                 chatInt := binary.BigEndian.Uint32(chatID)
 262                 privChat := cc.Server.PrivateChats[chatInt]
 263
 264                 clients := sortedClients(privChat.ClientConn)
 265
 266                 // send the message to all connected clients of the private chat
 267                 for _, c := range clients {
 268                         res = append(res, *NewTransaction(
 269                                 tranChatMsg,
 270                                 c.ID,
 271                                 NewField(fieldChatID, chatID),
 272                                 NewField(fieldData, []byte(formattedMsg)),
 273                         ))
 274                 }
 275                 return res, err
 276         }
 277
 278         for _, c := range sortedClients(cc.Server.Clients) {
 279                 // Filter out clients that do not have the read chat permission
 280                 if c.Authorize(accessReadChat) {
 281                         res = append(res, *NewTransaction(tranChatMsg, c.ID, NewField(fieldData, []byte(formattedMsg))))
 282                 }
 283         }
 284
 285         return res, err
 286 }
 287
 288 // HandleSendInstantMsg sends instant message to the user on the current server.
 289 // Fields used in the request:
 290 //
 291 //      103     User ID
 292 //      113     Options
 293 //              One of the following values:
 294 //              - User message (myOpt_UserMessage = 1)
 295 //              - Refuse message (myOpt_RefuseMessage = 2)
 296 //              - Refuse chat (myOpt_RefuseChat  = 3)
 297 //              - Automatic response (myOpt_AutomaticResponse = 4)"
 298 //      101     Data    Optional
 299 //      214     Quoting message Optional
 300 //
 301 // Fields used in the reply:
 302 // None
 303 func HandleSendInstantMsg(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 304         if !cc.Authorize(accessSendPrivMsg) {
 305                 res = append(res, cc.NewErrReply(t, "You are not allowed to send private messages."))
 306                 return res, err
 307         }
 308
 309         msg := t.GetField(fieldData)
 310         ID := t.GetField(fieldUserID)
 311
 312         reply := NewTransaction(
 313                 tranServerMsg,
 314                 &ID.Data,
 315                 NewField(fieldData, msg.Data),
 316                 NewField(fieldUserName, cc.UserName),
 317                 NewField(fieldUserID, *cc.ID),
 318                 NewField(fieldOptions, []byte{0, 1}),
 319         )
 320
 321         // Later versions of Hotline include the original message in the fieldQuotingMsg field so
 322         //  the receiving client can display both the received message and what it is in reply to
 323         if t.GetField(fieldQuotingMsg).Data != nil {
 324                 reply.Fields = append(reply.Fields, NewField(fieldQuotingMsg, t.GetField(fieldQuotingMsg).Data))
 325         }
 326
 327         id, _ := byteToInt(ID.Data)
 328         otherClient, ok := cc.Server.Clients[uint16(id)]
 329         if !ok {
 330                 return res, errors.New("invalid client ID")
 331         }
 332
 333         // Check if target user has "Refuse private messages" flag
 334         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(otherClient.Flags)))
 335         if flagBitmap.Bit(userFLagRefusePChat) == 1 {
 336                 res = append(res,
 337                         *NewTransaction(
 338                                 tranServerMsg,
 339                                 cc.ID,
 340                                 NewField(fieldData, []byte(string(otherClient.UserName)+" does not accept private messages.")),
 341                                 NewField(fieldUserName, otherClient.UserName),
 342                                 NewField(fieldUserID, *otherClient.ID),
 343                                 NewField(fieldOptions, []byte{0, 2}),
 344                         ),
 345                 )
 346         } else {
 347                 res = append(res, *reply)
 348         }
 349
 350         // Respond with auto reply if other client has it enabled
 351         if len(otherClient.AutoReply) > 0 {
 352                 res = append(res,
 353                         *NewTransaction(
 354                                 tranServerMsg,
 355                                 cc.ID,
 356                                 NewField(fieldData, otherClient.AutoReply),
 357                                 NewField(fieldUserName, otherClient.UserName),
 358                                 NewField(fieldUserID, *otherClient.ID),
 359                                 NewField(fieldOptions, []byte{0, 1}),
 360                         ),
 361                 )
 362         }
 363
 364         res = append(res, cc.NewReply(t))
 365
 366         return res, err
 367 }
 368
 369 func HandleGetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 370         fileName := t.GetField(fieldFileName).Data
 371         filePath := t.GetField(fieldFilePath).Data
 372
 373         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 374         if err != nil {
 375                 return res, err
 376         }
 377
 378         fw, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 379         if err != nil {
 380                 return res, err
 381         }
 382
 383         res = append(res, cc.NewReply(t,
 384                 NewField(fieldFileName, []byte(fw.name)),
 385                 NewField(fieldFileTypeString, fw.ffo.FlatFileInformationFork.friendlyType()),
 386                 NewField(fieldFileCreatorString, fw.ffo.FlatFileInformationFork.friendlyCreator()),
 387                 NewField(fieldFileComment, fw.ffo.FlatFileInformationFork.Comment),
 388                 NewField(fieldFileType, fw.ffo.FlatFileInformationFork.TypeSignature),
 389                 NewField(fieldFileCreateDate, fw.ffo.FlatFileInformationFork.CreateDate),
 390                 NewField(fieldFileModifyDate, fw.ffo.FlatFileInformationFork.ModifyDate),
 391                 NewField(fieldFileSize, fw.totalSize()),
 392         ))
 393         return res, err
 394 }
 395
 396 // HandleSetFileInfo updates a file or folder name and/or comment from the Get Info window
 397 // Fields used in the request:
 398 // * 201        File name
 399 // * 202        File path       Optional
 400 // * 211        File new name   Optional
 401 // * 210        File comment    Optional
 402 // Fields used in the reply:    None
 403 func HandleSetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 404         fileName := t.GetField(fieldFileName).Data
 405         filePath := t.GetField(fieldFilePath).Data
 406
 407         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 408         if err != nil {
 409                 return res, err
 410         }
 411
 412         fi, err := cc.Server.FS.Stat(fullFilePath)
 413         if err != nil {
 414                 return res, err
 415         }
 416
 417         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 418         if err != nil {
 419                 return res, err
 420         }
 421         if t.GetField(fieldFileComment).Data != nil {
 422                 switch mode := fi.Mode(); {
 423                 case mode.IsDir():
 424                         if !cc.Authorize(accessSetFolderComment) {
 425                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for folders."))
 426                                 return res, err
 427                         }
 428                 case mode.IsRegular():
 429                         if !cc.Authorize(accessSetFileComment) {
 430                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for files."))
 431                                 return res, err
 432                         }
 433                 }
 434
 435                 if err := hlFile.ffo.FlatFileInformationFork.setComment(t.GetField(fieldFileComment).Data); err != nil {
 436                         return res, err
 437                 }
 438                 w, err := hlFile.infoForkWriter()
 439                 if err != nil {
 440                         return res, err
 441                 }
 442                 _, err = w.Write(hlFile.ffo.FlatFileInformationFork.MarshalBinary())
 443                 if err != nil {
 444                         return res, err
 445                 }
 446         }
 447
 448         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, t.GetField(fieldFileNewName).Data)
 449         if err != nil {
 450                 return nil, err
 451         }
 452
 453         fileNewName := t.GetField(fieldFileNewName).Data
 454
 455         if fileNewName != nil {
 456                 switch mode := fi.Mode(); {
 457                 case mode.IsDir():
 458                         if !cc.Authorize(accessRenameFolder) {
 459                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename folders."))
 460                                 return res, err
 461                         }
 462                         err = os.Rename(fullFilePath, fullNewFilePath)
 463                         if os.IsNotExist(err) {
 464                                 res = append(res, cc.NewErrReply(t, "Cannot rename folder "+string(fileName)+" because it does not exist or cannot be found."))
 465                                 return res, err
 466                         }
 467                 case mode.IsRegular():
 468                         if !cc.Authorize(accessRenameFile) {
 469                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename files."))
 470                                 return res, err
 471                         }
 472                         fileDir, err := readPath(cc.Server.Config.FileRoot, filePath, []byte{})
 473                         if err != nil {
 474                                 return nil, err
 475                         }
 476                         hlFile.name = string(fileNewName)
 477                         err = hlFile.move(fileDir)
 478                         if os.IsNotExist(err) {
 479                                 res = append(res, cc.NewErrReply(t, "Cannot rename file "+string(fileName)+" because it does not exist or cannot be found."))
 480                                 return res, err
 481                         }
 482                         if err != nil {
 483                                 return res, err
 484                         }
 485                 }
 486         }
 487
 488         res = append(res, cc.NewReply(t))
 489         return res, err
 490 }
 491
 492 // HandleDeleteFile deletes a file or folder
 493 // Fields used in the request:
 494 // * 201        File name
 495 // * 202        File path
 496 // Fields used in the reply: none
 497 func HandleDeleteFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 498         fileName := t.GetField(fieldFileName).Data
 499         filePath := t.GetField(fieldFilePath).Data
 500
 501         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 502         if err != nil {
 503                 return res, err
 504         }
 505
 506         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 507         if err != nil {
 508                 return res, err
 509         }
 510
 511         fi, err := hlFile.dataFile()
 512         if err != nil {
 513                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+string(fileName)+" because it does not exist or cannot be found."))
 514                 return res, nil
 515         }
 516
 517         switch mode := fi.Mode(); {
 518         case mode.IsDir():
 519                 if !cc.Authorize(accessDeleteFolder) {
 520                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete folders."))
 521                         return res, err
 522                 }
 523         case mode.IsRegular():
 524                 if !cc.Authorize(accessDeleteFile) {
 525                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete files."))
 526                         return res, err
 527                 }
 528         }
 529
 530         if err := hlFile.delete(); err != nil {
 531                 return res, err
 532         }
 533
 534         res = append(res, cc.NewReply(t))
 535         return res, err
 536 }
 537
 538 // HandleMoveFile moves files or folders. Note: seemingly not documented
 539 func HandleMoveFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 540         fileName := string(t.GetField(fieldFileName).Data)
 541
 542         filePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
 543         if err != nil {
 544                 return res, err
 545         }
 546
 547         fileNewPath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFileNewPath).Data, nil)
 548         if err != nil {
 549                 return res, err
 550         }
 551
 552         cc.logger.Infow("Move file", "src", filePath+"/"+fileName, "dst", fileNewPath+"/"+fileName)
 553
 554         hlFile, err := newFileWrapper(cc.Server.FS, filePath, 0)
 555         if err != nil {
 556                 return res, err
 557         }
 558
 559         fi, err := hlFile.dataFile()
 560         if err != nil {
 561                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+fileName+" because it does not exist or cannot be found."))
 562                 return res, err
 563         }
 564         if err != nil {
 565                 return res, err
 566         }
 567         switch mode := fi.Mode(); {
 568         case mode.IsDir():
 569                 if !cc.Authorize(accessMoveFolder) {
 570                         res = append(res, cc.NewErrReply(t, "You are not allowed to move folders."))
 571                         return res, err
 572                 }
 573         case mode.IsRegular():
 574                 if !cc.Authorize(accessMoveFile) {
 575                         res = append(res, cc.NewErrReply(t, "You are not allowed to move files."))
 576                         return res, err
 577                 }
 578         }
 579         if err := hlFile.move(fileNewPath); err != nil {
 580                 return res, err
 581         }
 582         // TODO: handle other possible errors; e.g. fileWrapper delete fails due to fileWrapper permission issue
 583
 584         res = append(res, cc.NewReply(t))
 585         return res, err
 586 }
 587
 588 func HandleNewFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 589         if !cc.Authorize(accessCreateFolder) {
 590                 res = append(res, cc.NewErrReply(t, "You are not allowed to create folders."))
 591                 return res, err
 592         }
 593         folderName := string(t.GetField(fieldFileName).Data)
 594
 595         folderName = path.Join("/", folderName)
 596
 597         var subPath string
 598
 599         // fieldFilePath is only present for nested paths
 600         if t.GetField(fieldFilePath).Data != nil {
 601                 var newFp FilePath
 602                 _, err := newFp.Write(t.GetField(fieldFilePath).Data)
 603                 if err != nil {
 604                         return nil, err
 605                 }
 606
 607                 for _, pathItem := range newFp.Items {
 608                         subPath = filepath.Join("/", subPath, string(pathItem.Name))
 609                 }
 610         }
 611         newFolderPath := path.Join(cc.Server.Config.FileRoot, subPath, folderName)
 612
 613         // TODO: check path and folder name lengths
 614
 615         if _, err := cc.Server.FS.Stat(newFolderPath); !os.IsNotExist(err) {
 616                 msg := fmt.Sprintf("Cannot create folder \"%s\" because there is already a file or folder with that name.", folderName)
 617                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 618         }
 619
 620         // TODO: check for disallowed characters to maintain compatibility for original client
 621
 622         if err := cc.Server.FS.Mkdir(newFolderPath, 0777); err != nil {
 623                 msg := fmt.Sprintf("Cannot create folder \"%s\" because an error occurred.", folderName)
 624                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 625         }
 626
 627         res = append(res, cc.NewReply(t))
 628         return res, err
 629 }
 630
 631 func HandleSetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 632         if !cc.Authorize(accessModifyUser) {
 633                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 634                 return res, err
 635         }
 636
 637         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 638         userName := string(t.GetField(fieldUserName).Data)
 639
 640         newAccessLvl := t.GetField(fieldUserAccess).Data
 641
 642         account := cc.Server.Accounts[login]
 643         account.Name = userName
 644         copy(account.Access[:], newAccessLvl)
 645
 646         // If the password field is cleared in the Hotline edit user UI, the SetUser transaction does
 647         // not include fieldUserPassword
 648         if t.GetField(fieldUserPassword).Data == nil {
 649                 account.Password = hashAndSalt([]byte(""))
 650         }
 651         if len(t.GetField(fieldUserPassword).Data) > 1 {
 652                 account.Password = hashAndSalt(t.GetField(fieldUserPassword).Data)
 653         }
 654
 655         out, err := yaml.Marshal(&account)
 656         if err != nil {
 657                 return res, err
 658         }
 659         if err := os.WriteFile(filepath.Join(cc.Server.ConfigDir, "Users", login+".yaml"), out, 0666); err != nil {
 660                 return res, err
 661         }
 662
 663         // Notify connected clients logged in as the user of the new access level
 664         for _, c := range cc.Server.Clients {
 665                 if c.Account.Login == login {
 666                         // Note: comment out these two lines to test server-side deny messages
 667                         newT := NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, newAccessLvl))
 668                         res = append(res, *newT)
 669
 670                         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 671                         if c.Authorize(accessDisconUser) {
 672                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 1)
 673                         } else {
 674                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 0)
 675                         }
 676                         binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 677
 678                         c.Account.Access = account.Access
 679
 680                         cc.sendAll(
 681                                 tranNotifyChangeUser,
 682                                 NewField(fieldUserID, *c.ID),
 683                                 NewField(fieldUserFlags, c.Flags),
 684                                 NewField(fieldUserName, c.UserName),
 685                                 NewField(fieldUserIconID, c.Icon),
 686                         )
 687                 }
 688         }
 689
 690         res = append(res, cc.NewReply(t))
 691         return res, err
 692 }
 693
 694 func HandleGetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 695         if !cc.Authorize(accessOpenUser) {
 696                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 697                 return res, err
 698         }
 699
 700         account := cc.Server.Accounts[string(t.GetField(fieldUserLogin).Data)]
 701         if account == nil {
 702                 res = append(res, cc.NewErrReply(t, "Account does not exist."))
 703                 return res, err
 704         }
 705
 706         res = append(res, cc.NewReply(t,
 707                 NewField(fieldUserName, []byte(account.Name)),
 708                 NewField(fieldUserLogin, negateString(t.GetField(fieldUserLogin).Data)),
 709                 NewField(fieldUserPassword, []byte(account.Password)),
 710                 NewField(fieldUserAccess, account.Access[:]),
 711         ))
 712         return res, err
 713 }
 714
 715 func HandleListUsers(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 716         if !cc.Authorize(accessOpenUser) {
 717                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 718                 return res, err
 719         }
 720
 721         var userFields []Field
 722         for _, acc := range cc.Server.Accounts {
 723                 b := make([]byte, 0, 100)
 724                 n, err := acc.Read(b)
 725                 if err != nil {
 726                         return res, err
 727                 }
 728
 729                 userFields = append(userFields, NewField(fieldData, b[:n]))
 730         }
 731
 732         res = append(res, cc.NewReply(t, userFields...))
 733         return res, err
 734 }
 735
 736 // HandleUpdateUser is used by the v1.5+ multi-user editor to perform account editing for multiple users at a time.
 737 // An update can be a mix of these actions:
 738 // * Create user
 739 // * Delete user
 740 // * Modify user (including renaming the account login)
 741 //
 742 // The Transaction sent by the client includes one data field per user that was modified.  This data field in turn
 743 // contains another data field encoded in its payload with a varying number of sub fields depending on which action is
 744 // performed.  This seems to be the only place in the Hotline protocol where a data field contains another data field.
 745 func HandleUpdateUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 746         for _, field := range t.Fields {
 747                 subFields, err := ReadFields(field.Data[0:2], field.Data[2:])
 748                 if err != nil {
 749                         return res, err
 750                 }
 751
 752                 if len(subFields) == 1 {
 753                         login := DecodeUserString(getField(fieldData, &subFields).Data)
 754                         cc.logger.Infow("DeleteUser", "login", login)
 755
 756                         if !cc.Authorize(accessDeleteUser) {
 757                                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 758                                 return res, err
 759                         }
 760
 761                         if err := cc.Server.DeleteUser(login); err != nil {
 762                                 return res, err
 763                         }
 764                         continue
 765                 }
 766
 767                 login := DecodeUserString(getField(fieldUserLogin, &subFields).Data)
 768
 769                 // check if the login dataFile; if so, we know we are updating an existing user
 770                 if acc, ok := cc.Server.Accounts[login]; ok {
 771                         cc.logger.Infow("UpdateUser", "login", login)
 772
 773                         // account dataFile, so this is an update action
 774                         if !cc.Authorize(accessModifyUser) {
 775                                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 776                                 return res, err
 777                         }
 778
 779                         if getField(fieldUserPassword, &subFields) != nil {
 780                                 newPass := getField(fieldUserPassword, &subFields).Data
 781                                 acc.Password = hashAndSalt(newPass)
 782                         } else {
 783                                 acc.Password = hashAndSalt([]byte(""))
 784                         }
 785
 786                         if getField(fieldUserAccess, &subFields) != nil {
 787                                 copy(acc.Access[:], getField(fieldUserAccess, &subFields).Data)
 788                         }
 789
 790                         err = cc.Server.UpdateUser(
 791                                 DecodeUserString(getField(fieldData, &subFields).Data),
 792                                 DecodeUserString(getField(fieldUserLogin, &subFields).Data),
 793                                 string(getField(fieldUserName, &subFields).Data),
 794                                 acc.Password,
 795                                 acc.Access,
 796                         )
 797                         if err != nil {
 798                                 return res, err
 799                         }
 800                 } else {
 801                         cc.logger.Infow("CreateUser", "login", login)
 802
 803                         if !cc.Authorize(accessCreateUser) {
 804                                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 805                                 return res, err
 806                         }
 807
 808                         newAccess := accessBitmap{}
 809                         copy(newAccess[:], getField(fieldUserAccess, &subFields).Data[:])
 810
 811                         // Prevent account from creating new account with greater permission
 812                         for i := 0; i < 64; i++ {
 813                                 if newAccess.IsSet(i) {
 814                                         if !cc.Authorize(i) {
 815                                                 return append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself.")), err
 816                                         }
 817                                 }
 818                         }
 819
 820                         err := cc.Server.NewUser(login, string(getField(fieldUserName, &subFields).Data), string(getField(fieldUserPassword, &subFields).Data), newAccess)
 821                         if err != nil {
 822                                 return []Transaction{}, err
 823                         }
 824                 }
 825         }
 826
 827         res = append(res, cc.NewReply(t))
 828         return res, err
 829 }
 830
 831 // HandleNewUser creates a new user account
 832 func HandleNewUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 833         if !cc.Authorize(accessCreateUser) {
 834                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 835                 return res, err
 836         }
 837
 838         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 839
 840         // If the account already dataFile, reply with an error
 841         if _, ok := cc.Server.Accounts[login]; ok {
 842                 res = append(res, cc.NewErrReply(t, "Cannot create account "+login+" because there is already an account with that login."))
 843                 return res, err
 844         }
 845
 846         newAccess := accessBitmap{}
 847         copy(newAccess[:], t.GetField(fieldUserAccess).Data[:])
 848
 849         // Prevent account from creating new account with greater permission
 850         for i := 0; i < 64; i++ {
 851                 if newAccess.IsSet(i) {
 852                         if !cc.Authorize(i) {
 853                                 res = append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself."))
 854                                 return res, err
 855                         }
 856                 }
 857         }
 858
 859         if err := cc.Server.NewUser(login, string(t.GetField(fieldUserName).Data), string(t.GetField(fieldUserPassword).Data), newAccess); err != nil {
 860                 return []Transaction{}, err
 861         }
 862
 863         res = append(res, cc.NewReply(t))
 864         return res, err
 865 }
 866
 867 func HandleDeleteUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 868         if !cc.Authorize(accessDeleteUser) {
 869                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 870                 return res, err
 871         }
 872
 873         // TODO: Handle case where account doesn't exist; e.g. delete race condition
 874         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 875
 876         if err := cc.Server.DeleteUser(login); err != nil {
 877                 return res, err
 878         }
 879
 880         res = append(res, cc.NewReply(t))
 881         return res, err
 882 }
 883
 884 // HandleUserBroadcast sends an Administrator Message to all connected clients of the server
 885 func HandleUserBroadcast(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 886         if !cc.Authorize(accessBroadcast) {
 887                 res = append(res, cc.NewErrReply(t, "You are not allowed to send broadcast messages."))
 888                 return res, err
 889         }
 890
 891         cc.sendAll(
 892                 tranServerMsg,
 893                 NewField(fieldData, t.GetField(tranGetMsgs).Data),
 894                 NewField(fieldChatOptions, []byte{0}),
 895         )
 896
 897         res = append(res, cc.NewReply(t))
 898         return res, err
 899 }
 900
 901 // HandleGetClientInfoText returns user information for the specific user.
 902 //
 903 // Fields used in the request:
 904 // 103  User ID
 905 //
 906 // Fields used in the reply:
 907 // 102  User name
 908 // 101  Data            User info text string
 909 func HandleGetClientInfoText(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 910         if !cc.Authorize(accessGetClientInfo) {
 911                 res = append(res, cc.NewErrReply(t, "You are not allowed to get client info."))
 912                 return res, err
 913         }
 914
 915         clientID, _ := byteToInt(t.GetField(fieldUserID).Data)
 916
 917         clientConn := cc.Server.Clients[uint16(clientID)]
 918         if clientConn == nil {
 919                 return append(res, cc.NewErrReply(t, "User not found.")), err
 920         }
 921
 922         res = append(res, cc.NewReply(t,
 923                 NewField(fieldData, []byte(clientConn.String())),
 924                 NewField(fieldUserName, clientConn.UserName),
 925         ))
 926         return res, err
 927 }
 928
 929 func HandleGetUserNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 930         res = append(res, cc.NewReply(t, cc.Server.connectedUsers()...))
 931
 932         return res, err
 933 }
 934
 935 func HandleTranAgreed(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 936         if t.GetField(fieldUserName).Data != nil {
 937                 if cc.Authorize(accessAnyName) {
 938                         cc.UserName = t.GetField(fieldUserName).Data
 939                 } else {
 940                         cc.UserName = []byte(cc.Account.Name)
 941                 }
 942         }
 943
 944         cc.Icon = t.GetField(fieldUserIconID).Data
 945
 946         cc.logger = cc.logger.With("name", string(cc.UserName))
 947         cc.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(cc.Version); return i }()))
 948
 949         options := t.GetField(fieldOptions).Data
 950         optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
 951
 952         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
 953
 954         // Check refuse private PM option
 955         if optBitmap.Bit(refusePM) == 1 {
 956                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, 1)
 957                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
 958         }
 959
 960         // Check refuse private chat option
 961         if optBitmap.Bit(refuseChat) == 1 {
 962                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, 1)
 963                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
 964         }
 965
 966         // Check auto response
 967         if optBitmap.Bit(autoResponse) == 1 {
 968                 cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
 969         } else {
 970                 cc.AutoReply = []byte{}
 971         }
 972
 973         trans := cc.notifyOthers(
 974                 *NewTransaction(
 975                         tranNotifyChangeUser, nil,
 976                         NewField(fieldUserName, cc.UserName),
 977                         NewField(fieldUserID, *cc.ID),
 978                         NewField(fieldUserIconID, cc.Icon),
 979                         NewField(fieldUserFlags, cc.Flags),
 980                 ),
 981         )
 982         res = append(res, trans...)
 983
 984         if cc.Server.Config.BannerFile != "" {
 985                 res = append(res, *NewTransaction(tranServerBanner, cc.ID, NewField(fieldBannerType, []byte("JPEG"))))
 986         }
 987
 988         res = append(res, cc.NewReply(t))
 989
 990         return res, err
 991 }
 992
 993 const defaultNewsDateFormat = "Jan02 15:04" // Jun23 20:49
 994 //  "Mon, 02 Jan 2006 15:04:05 MST"
 995
 996 const defaultNewsTemplate = `From %s (%s):
 997
 998 %s
 999
1000 __________________________________________________________`
1001
1002 // HandleTranOldPostNews updates the flat news
1003 // Fields used in this request:
1004 // 101  Data
1005 func HandleTranOldPostNews(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1006         if !cc.Authorize(accessNewsPostArt) {
1007                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news."))
1008                 return res, err
1009         }
1010
1011         cc.Server.flatNewsMux.Lock()
1012         defer cc.Server.flatNewsMux.Unlock()
1013
1014         newsDateTemplate := defaultNewsDateFormat
1015         if cc.Server.Config.NewsDateFormat != "" {
1016                 newsDateTemplate = cc.Server.Config.NewsDateFormat
1017         }
1018
1019         newsTemplate := defaultNewsTemplate
1020         if cc.Server.Config.NewsDelimiter != "" {
1021                 newsTemplate = cc.Server.Config.NewsDelimiter
1022         }
1023
1024         newsPost := fmt.Sprintf(newsTemplate+"\r", cc.UserName, time.Now().Format(newsDateTemplate), t.GetField(fieldData).Data)
1025         newsPost = strings.Replace(newsPost, "\n", "\r", -1)
1026
1027         // update news in memory
1028         cc.Server.FlatNews = append([]byte(newsPost), cc.Server.FlatNews...)
1029
1030         // update news on disk
1031         if err := cc.Server.FS.WriteFile(filepath.Join(cc.Server.ConfigDir, "MessageBoard.txt"), cc.Server.FlatNews, 0644); err != nil {
1032                 return res, err
1033         }
1034
1035         // Notify all clients of updated news
1036         cc.sendAll(
1037                 tranNewMsg,
1038                 NewField(fieldData, []byte(newsPost)),
1039         )
1040
1041         res = append(res, cc.NewReply(t))
1042         return res, err
1043 }
1044
1045 func HandleDisconnectUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1046         if !cc.Authorize(accessDisconUser) {
1047                 res = append(res, cc.NewErrReply(t, "You are not allowed to disconnect users."))
1048                 return res, err
1049         }
1050
1051         clientConn := cc.Server.Clients[binary.BigEndian.Uint16(t.GetField(fieldUserID).Data)]
1052
1053         if clientConn.Authorize(accessCannotBeDiscon) {
1054                 res = append(res, cc.NewErrReply(t, clientConn.Account.Login+" is not allowed to be disconnected."))
1055                 return res, err
1056         }
1057
1058         // If fieldOptions is set, then the client IP is banned in addition to disconnected.
1059         // 00 01 = temporary ban
1060         // 00 02 = permanent ban
1061         if t.GetField(fieldOptions).Data != nil {
1062                 switch t.GetField(fieldOptions).Data[1] {
1063                 case 1:
1064                         // send message: "You are temporarily banned on this server"
1065                         cc.logger.Infow("Disconnect & temporarily ban " + string(clientConn.UserName))
1066
1067                         res = append(res, *NewTransaction(
1068                                 tranServerMsg,
1069                                 clientConn.ID,
1070                                 NewField(fieldData, []byte("You are temporarily banned on this server")),
1071                                 NewField(fieldChatOptions, []byte{0, 0}),
1072                         ))
1073
1074                         banUntil := time.Now().Add(tempBanDuration)
1075                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = &banUntil
1076                         cc.Server.writeBanList()
1077                 case 2:
1078                         // send message: "You are permanently banned on this server"
1079                         cc.logger.Infow("Disconnect & ban " + string(clientConn.UserName))
1080
1081                         res = append(res, *NewTransaction(
1082                                 tranServerMsg,
1083                                 clientConn.ID,
1084                                 NewField(fieldData, []byte("You are permanently banned on this server")),
1085                                 NewField(fieldChatOptions, []byte{0, 0}),
1086                         ))
1087
1088                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = nil
1089                         cc.Server.writeBanList()
1090                 }
1091         }
1092
1093         // TODO: remove this awful hack
1094         go func() {
1095                 time.Sleep(1 * time.Second)
1096                 clientConn.Disconnect()
1097         }()
1098
1099         return append(res, cc.NewReply(t)), err
1100 }
1101
1102 // HandleGetNewsCatNameList returns a list of news categories for a path
1103 // Fields used in the request:
1104 // 325  News path       (Optional)
1105 func HandleGetNewsCatNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1106         if !cc.Authorize(accessNewsReadArt) {
1107                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1108                 return res, err
1109         }
1110
1111         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1112         cats := cc.Server.GetNewsCatByPath(pathStrs)
1113
1114         // To store the keys in slice in sorted order
1115         keys := make([]string, len(cats))
1116         i := 0
1117         for k := range cats {
1118                 keys[i] = k
1119                 i++
1120         }
1121         sort.Strings(keys)
1122
1123         var fieldData []Field
1124         for _, k := range keys {
1125                 cat := cats[k]
1126                 b, _ := cat.MarshalBinary()
1127                 fieldData = append(fieldData, NewField(
1128                         fieldNewsCatListData15,
1129                         b,
1130                 ))
1131         }
1132
1133         res = append(res, cc.NewReply(t, fieldData...))
1134         return res, err
1135 }
1136
1137 func HandleNewNewsCat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1138         if !cc.Authorize(accessNewsCreateCat) {
1139                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news categories."))
1140                 return res, err
1141         }
1142
1143         name := string(t.GetField(fieldNewsCatName).Data)
1144         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1145
1146         cats := cc.Server.GetNewsCatByPath(pathStrs)
1147         cats[name] = NewsCategoryListData15{
1148                 Name:     name,
1149                 Type:     []byte{0, 3},
1150                 Articles: map[uint32]*NewsArtData{},
1151                 SubCats:  make(map[string]NewsCategoryListData15),
1152         }
1153
1154         if err := cc.Server.writeThreadedNews(); err != nil {
1155                 return res, err
1156         }
1157         res = append(res, cc.NewReply(t))
1158         return res, err
1159 }
1160
1161 // Fields used in the request:
1162 // 322  News category name
1163 // 325  News path
1164 func HandleNewNewsFldr(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1165         if !cc.Authorize(accessNewsCreateFldr) {
1166                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news folders."))
1167                 return res, err
1168         }
1169
1170         name := string(t.GetField(fieldFileName).Data)
1171         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1172
1173         cc.logger.Infof("Creating new news folder %s", name)
1174
1175         cats := cc.Server.GetNewsCatByPath(pathStrs)
1176         cats[name] = NewsCategoryListData15{
1177                 Name:     name,
1178                 Type:     []byte{0, 2},
1179                 Articles: map[uint32]*NewsArtData{},
1180                 SubCats:  make(map[string]NewsCategoryListData15),
1181         }
1182         if err := cc.Server.writeThreadedNews(); err != nil {
1183                 return res, err
1184         }
1185         res = append(res, cc.NewReply(t))
1186         return res, err
1187 }
1188
1189 // HandleGetNewsArtData gets the list of article names at the specified news path.
1190
1191 // Fields used in the request:
1192 // 325  News path       Optional
1193
1194 // Fields used in the reply:
1195 // 321  News article list data  Optional
1196 func HandleGetNewsArtNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1197         if !cc.Authorize(accessNewsReadArt) {
1198                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1199                 return res, err
1200         }
1201         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1202
1203         var cat NewsCategoryListData15
1204         cats := cc.Server.ThreadedNews.Categories
1205
1206         for _, fp := range pathStrs {
1207                 cat = cats[fp]
1208                 cats = cats[fp].SubCats
1209         }
1210
1211         nald := cat.GetNewsArtListData()
1212
1213         res = append(res, cc.NewReply(t, NewField(fieldNewsArtListData, nald.Payload())))
1214         return res, err
1215 }
1216
1217 // HandleGetNewsArtData requests information about the specific news article.
1218 // Fields used in the request:
1219 //
1220 // Request fields
1221 // 325  News path
1222 // 326  News article ID
1223 // 327  News article data flavor
1224 //
1225 // Fields used in the reply:
1226 // 328  News article title
1227 // 329  News article poster
1228 // 330  News article date
1229 // 331  Previous article ID
1230 // 332  Next article ID
1231 // 335  Parent article ID
1232 // 336  First child article ID
1233 // 327  News article data flavor        "Should be “text/plain”
1234 // 333  News article data       Optional (if data flavor is “text/plain”)
1235 func HandleGetNewsArtData(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1236         if !cc.Authorize(accessNewsReadArt) {
1237                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1238                 return res, err
1239         }
1240
1241         var cat NewsCategoryListData15
1242         cats := cc.Server.ThreadedNews.Categories
1243
1244         for _, fp := range ReadNewsPath(t.GetField(fieldNewsPath).Data) {
1245                 cat = cats[fp]
1246                 cats = cats[fp].SubCats
1247         }
1248
1249         // The official Hotline clients will send the article ID as 2 bytes if possible, but
1250         // some third party clients such as Frogblast and Heildrun will always send 4 bytes
1251         convertedID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1252         if err != nil {
1253                 return res, err
1254         }
1255
1256         art := cat.Articles[uint32(convertedID)]
1257         if art == nil {
1258                 res = append(res, cc.NewReply(t))
1259                 return res, err
1260         }
1261
1262         res = append(res, cc.NewReply(t,
1263                 NewField(fieldNewsArtTitle, []byte(art.Title)),
1264                 NewField(fieldNewsArtPoster, []byte(art.Poster)),
1265                 NewField(fieldNewsArtDate, art.Date),
1266                 NewField(fieldNewsArtPrevArt, art.PrevArt),
1267                 NewField(fieldNewsArtNextArt, art.NextArt),
1268                 NewField(fieldNewsArtParentArt, art.ParentArt),
1269                 NewField(fieldNewsArt1stChildArt, art.FirstChildArt),
1270                 NewField(fieldNewsArtDataFlav, []byte("text/plain")),
1271                 NewField(fieldNewsArtData, []byte(art.Data)),
1272         ))
1273         return res, err
1274 }
1275
1276 // HandleDelNewsItem deletes an existing threaded news folder or category from the server.
1277 // Fields used in the request:
1278 // 325  News path
1279 // Fields used in the reply:
1280 // None
1281 func HandleDelNewsItem(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1282         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1283
1284         cats := cc.Server.ThreadedNews.Categories
1285         delName := pathStrs[len(pathStrs)-1]
1286         if len(pathStrs) > 1 {
1287                 for _, fp := range pathStrs[0 : len(pathStrs)-1] {
1288                         cats = cats[fp].SubCats
1289                 }
1290         }
1291
1292         if bytes.Equal(cats[delName].Type, []byte{0, 3}) {
1293                 if !cc.Authorize(accessNewsDeleteCat) {
1294                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news categories.")), nil
1295                 }
1296         } else {
1297                 if !cc.Authorize(accessNewsDeleteFldr) {
1298                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news folders.")), nil
1299                 }
1300         }
1301
1302         delete(cats, delName)
1303
1304         if err := cc.Server.writeThreadedNews(); err != nil {
1305                 return res, err
1306         }
1307
1308         return append(res, cc.NewReply(t)), nil
1309 }
1310
1311 func HandleDelNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1312         if !cc.Authorize(accessNewsDeleteArt) {
1313                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete news articles."))
1314                 return res, err
1315         }
1316
1317         // Request Fields
1318         // 325  News path
1319         // 326  News article ID
1320         // 337  News article – recursive delete       Delete child articles (1) or not (0)
1321         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1322         ID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1323         if err != nil {
1324                 return res, err
1325         }
1326
1327         // TODO: Delete recursive
1328         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1329
1330         catName := pathStrs[len(pathStrs)-1]
1331         cat := cats[catName]
1332
1333         delete(cat.Articles, uint32(ID))
1334
1335         cats[catName] = cat
1336         if err := cc.Server.writeThreadedNews(); err != nil {
1337                 return res, err
1338         }
1339
1340         res = append(res, cc.NewReply(t))
1341         return res, err
1342 }
1343
1344 // Request fields
1345 // 325  News path
1346 // 326  News article ID                                                 ID of the parent article?
1347 // 328  News article title
1348 // 334  News article flags
1349 // 327  News article data flavor                Currently “text/plain”
1350 // 333  News article data
1351 func HandlePostNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1352         if !cc.Authorize(accessNewsPostArt) {
1353                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news articles."))
1354                 return res, err
1355         }
1356
1357         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1358         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1359
1360         catName := pathStrs[len(pathStrs)-1]
1361         cat := cats[catName]
1362
1363         artID, err := byteToInt(t.GetField(fieldNewsArtID).Data)
1364         if err != nil {
1365                 return res, err
1366         }
1367         convertedArtID := uint32(artID)
1368         bs := make([]byte, 4)
1369         binary.LittleEndian.PutUint32(bs, convertedArtID)
1370
1371         newArt := NewsArtData{
1372                 Title:         string(t.GetField(fieldNewsArtTitle).Data),
1373                 Poster:        string(cc.UserName),
1374                 Date:          toHotlineTime(time.Now()),
1375                 PrevArt:       []byte{0, 0, 0, 0},
1376                 NextArt:       []byte{0, 0, 0, 0},
1377                 ParentArt:     bs,
1378                 FirstChildArt: []byte{0, 0, 0, 0},
1379                 DataFlav:      []byte("text/plain"),
1380                 Data:          string(t.GetField(fieldNewsArtData).Data),
1381         }
1382
1383         var keys []int
1384         for k := range cat.Articles {
1385                 keys = append(keys, int(k))
1386         }
1387
1388         nextID := uint32(1)
1389         if len(keys) > 0 {
1390                 sort.Ints(keys)
1391                 prevID := uint32(keys[len(keys)-1])
1392                 nextID = prevID + 1
1393
1394                 binary.BigEndian.PutUint32(newArt.PrevArt, prevID)
1395
1396                 // Set next article ID
1397                 binary.BigEndian.PutUint32(cat.Articles[prevID].NextArt, nextID)
1398         }
1399
1400         // Update parent article with first child reply
1401         parentID := convertedArtID
1402         if parentID != 0 {
1403                 parentArt := cat.Articles[parentID]
1404
1405                 if bytes.Equal(parentArt.FirstChildArt, []byte{0, 0, 0, 0}) {
1406                         binary.BigEndian.PutUint32(parentArt.FirstChildArt, nextID)
1407                 }
1408         }
1409
1410         cat.Articles[nextID] = &newArt
1411
1412         cats[catName] = cat
1413         if err := cc.Server.writeThreadedNews(); err != nil {
1414                 return res, err
1415         }
1416
1417         res = append(res, cc.NewReply(t))
1418         return res, err
1419 }
1420
1421 // HandleGetMsgs returns the flat news data
1422 func HandleGetMsgs(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1423         if !cc.Authorize(accessNewsReadArt) {
1424                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1425                 return res, err
1426         }
1427
1428         res = append(res, cc.NewReply(t, NewField(fieldData, cc.Server.FlatNews)))
1429
1430         return res, err
1431 }
1432
1433 func HandleDownloadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1434         if !cc.Authorize(accessDownloadFile) {
1435                 res = append(res, cc.NewErrReply(t, "You are not allowed to download files."))
1436                 return res, err
1437         }
1438
1439         fileName := t.GetField(fieldFileName).Data
1440         filePath := t.GetField(fieldFilePath).Data
1441         resumeData := t.GetField(fieldFileResumeData).Data
1442
1443         var dataOffset int64
1444         var frd FileResumeData
1445         if resumeData != nil {
1446                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1447                         return res, err
1448                 }
1449                 // TODO: handle rsrc fork offset
1450                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1451         }
1452
1453         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1454         if err != nil {
1455                 return res, err
1456         }
1457
1458         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, dataOffset)
1459         if err != nil {
1460                 return res, err
1461         }
1462
1463         xferSize := hlFile.ffo.TransferSize(0)
1464
1465         ft := cc.newFileTransfer(FileDownload, fileName, filePath, xferSize)
1466
1467         // TODO: refactor to remove this
1468         if resumeData != nil {
1469                 var frd FileResumeData
1470                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1471                         return res, err
1472                 }
1473                 ft.fileResumeData = &frd
1474         }
1475
1476         // Optional field for when a HL v1.5+ client requests file preview
1477         // Used only for TEXT, JPEG, GIFF, BMP or PICT files
1478         // The value will always be 2
1479         if t.GetField(fieldFileTransferOptions).Data != nil {
1480                 ft.options = t.GetField(fieldFileTransferOptions).Data
1481                 xferSize = hlFile.ffo.FlatFileDataForkHeader.DataSize[:]
1482         }
1483
1484         res = append(res, cc.NewReply(t,
1485                 NewField(fieldRefNum, ft.refNum[:]),
1486                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1487                 NewField(fieldTransferSize, xferSize),
1488                 NewField(fieldFileSize, hlFile.ffo.FlatFileDataForkHeader.DataSize[:]),
1489         ))
1490
1491         return res, err
1492 }
1493
1494 // Download all files from the specified folder and sub-folders
1495 func HandleDownloadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1496         if !cc.Authorize(accessDownloadFile) {
1497                 res = append(res, cc.NewErrReply(t, "You are not allowed to download folders."))
1498                 return res, err
1499         }
1500
1501         fullFilePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
1502         if err != nil {
1503                 return res, err
1504         }
1505
1506         transferSize, err := CalcTotalSize(fullFilePath)
1507         if err != nil {
1508                 return res, err
1509         }
1510         itemCount, err := CalcItemCount(fullFilePath)
1511         if err != nil {
1512                 return res, err
1513         }
1514
1515         fileTransfer := cc.newFileTransfer(FolderDownload, t.GetField(fieldFileName).Data, t.GetField(fieldFilePath).Data, transferSize)
1516
1517         var fp FilePath
1518         _, err = fp.Write(t.GetField(fieldFilePath).Data)
1519         if err != nil {
1520                 return res, err
1521         }
1522
1523         res = append(res, cc.NewReply(t,
1524                 NewField(fieldRefNum, fileTransfer.ReferenceNumber),
1525                 NewField(fieldTransferSize, transferSize),
1526                 NewField(fieldFolderItemCount, itemCount),
1527                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1528         ))
1529         return res, err
1530 }
1531
1532 // Upload all files from the local folder and its subfolders to the specified path on the server
1533 // Fields used in the request
1534 // 201  File name
1535 // 202  File path
1536 // 108  transfer size   Total size of all items in the folder
1537 // 220  Folder item count
1538 // 204  File transfer options   "Optional Currently set to 1" (TODO: ??)
1539 func HandleUploadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1540         var fp FilePath
1541         if t.GetField(fieldFilePath).Data != nil {
1542                 if _, err = fp.Write(t.GetField(fieldFilePath).Data); err != nil {
1543                         return res, err
1544                 }
1545         }
1546
1547         // Handle special cases for Upload and Drop Box folders
1548         if !cc.Authorize(accessUploadAnywhere) {
1549                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1550                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the folder \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(t.GetField(fieldFileName).Data))))
1551                         return res, err
1552                 }
1553         }
1554
1555         fileTransfer := cc.newFileTransfer(FolderUpload,
1556                 t.GetField(fieldFileName).Data,
1557                 t.GetField(fieldFilePath).Data,
1558                 t.GetField(fieldTransferSize).Data,
1559         )
1560
1561         fileTransfer.FolderItemCount = t.GetField(fieldFolderItemCount).Data
1562
1563         res = append(res, cc.NewReply(t, NewField(fieldRefNum, fileTransfer.ReferenceNumber)))
1564         return res, err
1565 }
1566
1567 // HandleUploadFile
1568 // Fields used in the request:
1569 // 201  File name
1570 // 202  File path
1571 // 204  File transfer options   "Optional
1572 // Used only to resume download, currently has value 2"
1573 // 108  File transfer size      "Optional used if download is not resumed"
1574 func HandleUploadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1575         if !cc.Authorize(accessUploadFile) {
1576                 res = append(res, cc.NewErrReply(t, "You are not allowed to upload files."))
1577                 return res, err
1578         }
1579
1580         fileName := t.GetField(fieldFileName).Data
1581         filePath := t.GetField(fieldFilePath).Data
1582         transferOptions := t.GetField(fieldFileTransferOptions).Data
1583         transferSize := t.GetField(fieldTransferSize).Data // not sent for resume
1584
1585         var fp FilePath
1586         if filePath != nil {
1587                 if _, err = fp.Write(filePath); err != nil {
1588                         return res, err
1589                 }
1590         }
1591
1592         // Handle special cases for Upload and Drop Box folders
1593         if !cc.Authorize(accessUploadAnywhere) {
1594                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1595                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the file \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(fileName))))
1596                         return res, err
1597                 }
1598         }
1599         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1600         if err != nil {
1601                 return res, err
1602         }
1603
1604         if _, err := cc.Server.FS.Stat(fullFilePath); err == nil {
1605                 res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload because there is already a file named \"%v\".  Try choosing a different name.", string(fileName))))
1606                 return res, err
1607         }
1608
1609         ft := cc.newFileTransfer(FileUpload, fileName, filePath, transferSize)
1610
1611         replyT := cc.NewReply(t, NewField(fieldRefNum, ft.ReferenceNumber))
1612
1613         // client has requested to resume a partially transferred file
1614         if transferOptions != nil {
1615
1616                 fileInfo, err := cc.Server.FS.Stat(fullFilePath + incompleteFileSuffix)
1617                 if err != nil {
1618                         return res, err
1619                 }
1620
1621                 offset := make([]byte, 4)
1622                 binary.BigEndian.PutUint32(offset, uint32(fileInfo.Size()))
1623
1624                 fileResumeData := NewFileResumeData([]ForkInfoList{
1625                         *NewForkInfoList(offset),
1626                 })
1627
1628                 b, _ := fileResumeData.BinaryMarshal()
1629
1630                 ft.TransferSize = offset
1631
1632                 replyT.Fields = append(replyT.Fields, NewField(fieldFileResumeData, b))
1633         }
1634
1635         res = append(res, replyT)
1636         return res, err
1637 }
1638
1639 func HandleSetClientUserInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1640         if len(t.GetField(fieldUserIconID).Data) == 4 {
1641                 cc.Icon = t.GetField(fieldUserIconID).Data[2:]
1642         } else {
1643                 cc.Icon = t.GetField(fieldUserIconID).Data
1644         }
1645         if cc.Authorize(accessAnyName) {
1646                 cc.UserName = t.GetField(fieldUserName).Data
1647         }
1648
1649         // the options field is only passed by the client versions > 1.2.3.
1650         options := t.GetField(fieldOptions).Data
1651         if options != nil {
1652                 optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1653                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
1654
1655                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, optBitmap.Bit(refusePM))
1656                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1657
1658                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, optBitmap.Bit(refuseChat))
1659                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1660
1661                 // Check auto response
1662                 if optBitmap.Bit(autoResponse) == 1 {
1663                         cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
1664                 } else {
1665                         cc.AutoReply = []byte{}
1666                 }
1667         }
1668
1669         for _, c := range sortedClients(cc.Server.Clients) {
1670                 res = append(res, *NewTransaction(
1671                         tranNotifyChangeUser,
1672                         c.ID,
1673                         NewField(fieldUserID, *cc.ID),
1674                         NewField(fieldUserIconID, cc.Icon),
1675                         NewField(fieldUserFlags, cc.Flags),
1676                         NewField(fieldUserName, cc.UserName),
1677                 ))
1678         }
1679
1680         return res, err
1681 }
1682
1683 // HandleKeepAlive responds to keepalive transactions with an empty reply
1684 // * HL 1.9.2 Client sends keepalive msg every 3 minutes
1685 // * HL 1.2.3 Client doesn't send keepalives
1686 func HandleKeepAlive(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1687         res = append(res, cc.NewReply(t))
1688
1689         return res, err
1690 }
1691
1692 func HandleGetFileNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1693         fullPath, err := readPath(
1694                 cc.Server.Config.FileRoot,
1695                 t.GetField(fieldFilePath).Data,
1696                 nil,
1697         )
1698         if err != nil {
1699                 return res, err
1700         }
1701
1702         var fp FilePath
1703         if t.GetField(fieldFilePath).Data != nil {
1704                 if _, err = fp.Write(t.GetField(fieldFilePath).Data); err != nil {
1705                         return res, err
1706                 }
1707         }
1708
1709         // Handle special case for drop box folders
1710         if fp.IsDropbox() && !cc.Authorize(accessViewDropBoxes) {
1711                 res = append(res, cc.NewErrReply(t, "You are not allowed to view drop boxes."))
1712                 return res, err
1713         }
1714
1715         fileNames, err := getFileNameList(fullPath, cc.Server.Config.IgnoreFiles)
1716         if err != nil {
1717                 return res, err
1718         }
1719
1720         res = append(res, cc.NewReply(t, fileNames...))
1721
1722         return res, err
1723 }
1724
1725 // =================================
1726 //     Hotline private chat flow
1727 // =================================
1728 // 1. ClientA sends tranInviteNewChat to server with user ID to invite
1729 // 2. Server creates new ChatID
1730 // 3. Server sends tranInviteToChat to invitee
1731 // 4. Server replies to ClientA with new Chat ID
1732 //
1733 // A dialog box pops up in the invitee client with options to accept or decline the invitation.
1734 // If Accepted is clicked:
1735 // 1. ClientB sends tranJoinChat with fieldChatID
1736
1737 // HandleInviteNewChat invites users to new private chat
1738 func HandleInviteNewChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1739         if !cc.Authorize(accessOpenChat) {
1740                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1741                 return res, err
1742         }
1743
1744         // Client to Invite
1745         targetID := t.GetField(fieldUserID).Data
1746         newChatID := cc.Server.NewPrivateChat(cc)
1747
1748         // Check if target user has "Refuse private chat" flag
1749         binary.BigEndian.Uint16(targetID)
1750         targetClient := cc.Server.Clients[binary.BigEndian.Uint16(targetID)]
1751
1752         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(targetClient.Flags)))
1753         if flagBitmap.Bit(userFLagRefusePChat) == 1 {
1754                 res = append(res,
1755                         *NewTransaction(
1756                                 tranServerMsg,
1757                                 cc.ID,
1758                                 NewField(fieldData, []byte(string(targetClient.UserName)+" does not accept private chats.")),
1759                                 NewField(fieldUserName, targetClient.UserName),
1760                                 NewField(fieldUserID, *targetClient.ID),
1761                                 NewField(fieldOptions, []byte{0, 2}),
1762                         ),
1763                 )
1764         } else {
1765                 res = append(res,
1766                         *NewTransaction(
1767                                 tranInviteToChat,
1768                                 &targetID,
1769                                 NewField(fieldChatID, newChatID),
1770                                 NewField(fieldUserName, cc.UserName),
1771                                 NewField(fieldUserID, *cc.ID),
1772                         ),
1773                 )
1774         }
1775
1776         res = append(res,
1777                 cc.NewReply(t,
1778                         NewField(fieldChatID, newChatID),
1779                         NewField(fieldUserName, cc.UserName),
1780                         NewField(fieldUserID, *cc.ID),
1781                         NewField(fieldUserIconID, cc.Icon),
1782                         NewField(fieldUserFlags, cc.Flags),
1783                 ),
1784         )
1785
1786         return res, err
1787 }
1788
1789 func HandleInviteToChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1790         if !cc.Authorize(accessOpenChat) {
1791                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1792                 return res, err
1793         }
1794
1795         // Client to Invite
1796         targetID := t.GetField(fieldUserID).Data
1797         chatID := t.GetField(fieldChatID).Data
1798
1799         res = append(res,
1800                 *NewTransaction(
1801                         tranInviteToChat,
1802                         &targetID,
1803                         NewField(fieldChatID, chatID),
1804                         NewField(fieldUserName, cc.UserName),
1805                         NewField(fieldUserID, *cc.ID),
1806                 ),
1807         )
1808         res = append(res,
1809                 cc.NewReply(
1810                         t,
1811                         NewField(fieldChatID, chatID),
1812                         NewField(fieldUserName, cc.UserName),
1813                         NewField(fieldUserID, *cc.ID),
1814                         NewField(fieldUserIconID, cc.Icon),
1815                         NewField(fieldUserFlags, cc.Flags),
1816                 ),
1817         )
1818
1819         return res, err
1820 }
1821
1822 func HandleRejectChatInvite(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1823         chatID := t.GetField(fieldChatID).Data
1824         chatInt := binary.BigEndian.Uint32(chatID)
1825
1826         privChat := cc.Server.PrivateChats[chatInt]
1827
1828         resMsg := append(cc.UserName, []byte(" declined invitation to chat")...)
1829
1830         for _, c := range sortedClients(privChat.ClientConn) {
1831                 res = append(res,
1832                         *NewTransaction(
1833                                 tranChatMsg,
1834                                 c.ID,
1835                                 NewField(fieldChatID, chatID),
1836                                 NewField(fieldData, resMsg),
1837                         ),
1838                 )
1839         }
1840
1841         return res, err
1842 }
1843
1844 // HandleJoinChat is sent from a v1.8+ Hotline client when the joins a private chat
1845 // Fields used in the reply:
1846 // * 115        Chat subject
1847 // * 300        User name with info (Optional)
1848 // * 300        (more user names with info)
1849 func HandleJoinChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1850         chatID := t.GetField(fieldChatID).Data
1851         chatInt := binary.BigEndian.Uint32(chatID)
1852
1853         privChat := cc.Server.PrivateChats[chatInt]
1854
1855         // Send tranNotifyChatChangeUser to current members of the chat to inform of new user
1856         for _, c := range sortedClients(privChat.ClientConn) {
1857                 res = append(res,
1858                         *NewTransaction(
1859                                 tranNotifyChatChangeUser,
1860                                 c.ID,
1861                                 NewField(fieldChatID, chatID),
1862                                 NewField(fieldUserName, cc.UserName),
1863                                 NewField(fieldUserID, *cc.ID),
1864                                 NewField(fieldUserIconID, cc.Icon),
1865                                 NewField(fieldUserFlags, cc.Flags),
1866                         ),
1867                 )
1868         }
1869
1870         privChat.ClientConn[cc.uint16ID()] = cc
1871
1872         replyFields := []Field{NewField(fieldChatSubject, []byte(privChat.Subject))}
1873         for _, c := range sortedClients(privChat.ClientConn) {
1874                 user := User{
1875                         ID:    *c.ID,
1876                         Icon:  c.Icon,
1877                         Flags: c.Flags,
1878                         Name:  string(c.UserName),
1879                 }
1880
1881                 replyFields = append(replyFields, NewField(fieldUsernameWithInfo, user.Payload()))
1882         }
1883
1884         res = append(res, cc.NewReply(t, replyFields...))
1885         return res, err
1886 }
1887
1888 // HandleLeaveChat is sent from a v1.8+ Hotline client when the user exits a private chat
1889 // Fields used in the request:
1890 //   - 114      fieldChatID
1891 //
1892 // Reply is not expected.
1893 func HandleLeaveChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1894         chatID := t.GetField(fieldChatID).Data
1895         chatInt := binary.BigEndian.Uint32(chatID)
1896
1897         privChat, ok := cc.Server.PrivateChats[chatInt]
1898         if !ok {
1899                 return res, nil
1900         }
1901
1902         delete(privChat.ClientConn, cc.uint16ID())
1903
1904         // Notify members of the private chat that the user has left
1905         for _, c := range sortedClients(privChat.ClientConn) {
1906                 res = append(res,
1907                         *NewTransaction(
1908                                 tranNotifyChatDeleteUser,
1909                                 c.ID,
1910                                 NewField(fieldChatID, chatID),
1911                                 NewField(fieldUserID, *cc.ID),
1912                         ),
1913                 )
1914         }
1915
1916         return res, err
1917 }
1918
1919 // HandleSetChatSubject is sent from a v1.8+ Hotline client when the user sets a private chat subject
1920 // Fields used in the request:
1921 // * 114        Chat ID
1922 // * 115        Chat subject    Chat subject string
1923 // Reply is not expected.
1924 func HandleSetChatSubject(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1925         chatID := t.GetField(fieldChatID).Data
1926         chatInt := binary.BigEndian.Uint32(chatID)
1927
1928         privChat := cc.Server.PrivateChats[chatInt]
1929         privChat.Subject = string(t.GetField(fieldChatSubject).Data)
1930
1931         for _, c := range sortedClients(privChat.ClientConn) {
1932                 res = append(res,
1933                         *NewTransaction(
1934                                 tranNotifyChatSubject,
1935                                 c.ID,
1936                                 NewField(fieldChatID, chatID),
1937                                 NewField(fieldChatSubject, t.GetField(fieldChatSubject).Data),
1938                         ),
1939                 )
1940         }
1941
1942         return res, err
1943 }
1944
1945 // HandleMakeAlias makes a filer alias using the specified path.
1946 // Fields used in the request:
1947 // 201  File name
1948 // 202  File path
1949 // 212  File new path   Destination path
1950 //
1951 // Fields used in the reply:
1952 // None
1953 func HandleMakeAlias(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1954         if !cc.Authorize(accessMakeAlias) {
1955                 res = append(res, cc.NewErrReply(t, "You are not allowed to make aliases."))
1956                 return res, err
1957         }
1958         fileName := t.GetField(fieldFileName).Data
1959         filePath := t.GetField(fieldFilePath).Data
1960         fileNewPath := t.GetField(fieldFileNewPath).Data
1961
1962         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1963         if err != nil {
1964                 return res, err
1965         }
1966
1967         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, fileNewPath, fileName)
1968         if err != nil {
1969                 return res, err
1970         }
1971
1972         cc.logger.Debugw("Make alias", "src", fullFilePath, "dst", fullNewFilePath)
1973
1974         if err := cc.Server.FS.Symlink(fullFilePath, fullNewFilePath); err != nil {
1975                 res = append(res, cc.NewErrReply(t, "Error creating alias"))
1976                 return res, nil
1977         }
1978
1979         res = append(res, cc.NewReply(t))
1980         return res, err
1981 }
1982
1983 // HandleDownloadBanner handles requests for a new banner from the server
1984 // Fields used in the request:
1985 // None
1986 // Fields used in the reply:
1987 // 107  fieldRefNum                     Used later for transfer
1988 // 108  fieldTransferSize       Size of data to be downloaded
1989 func HandleDownloadBanner(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1990         fi, err := cc.Server.FS.Stat(filepath.Join(cc.Server.ConfigDir, cc.Server.Config.BannerFile))
1991         if err != nil {
1992                 return res, err
1993         }
1994
1995         ft := cc.newFileTransfer(bannerDownload, []byte{}, []byte{}, make([]byte, 4))
1996
1997         binary.BigEndian.PutUint32(ft.TransferSize, uint32(fi.Size()))
1998
1999         res = append(res, cc.NewReply(t,
2000                 NewField(fieldRefNum, ft.refNum[:]),
2001                 NewField(fieldTransferSize, ft.TransferSize),
2002         ))
2003
2004         return res, err
2005 }