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 HandlerFunc func(*ClientConn, *Transaction) ([]Transaction, error)
  19
  20 type TransactionType struct {
  21         Handler        HandlerFunc // function for handling the transaction type
  22         Name           string      // Name of transaction as it will appear in logging
  23         RequiredFields []requiredField
  24 }
  25
  26 var TransactionHandlers = map[uint16]TransactionType{
  27         // Server initiated
  28         TranChatMsg: {
  29                 Name: "TranChatMsg",
  30         },
  31         // Server initiated
  32         TranNotifyChangeUser: {
  33                 Name: "TranNotifyChangeUser",
  34         },
  35         TranError: {
  36                 Name: "TranError",
  37         },
  38         TranShowAgreement: {
  39                 Name: "TranShowAgreement",
  40         },
  41         TranUserAccess: {
  42                 Name: "TranUserAccess",
  43         },
  44         TranNotifyDeleteUser: {
  45                 Name: "TranNotifyDeleteUser",
  46         },
  47         TranAgreed: {
  48                 Name:    "TranAgreed",
  49                 Handler: HandleTranAgreed,
  50         },
  51         TranChatSend: {
  52                 Name:    "TranChatSend",
  53                 Handler: HandleChatSend,
  54                 RequiredFields: []requiredField{
  55                         {
  56                                 ID:     FieldData,
  57                                 minLen: 0,
  58                         },
  59                 },
  60         },
  61         TranDelNewsArt: {
  62                 Name:    "TranDelNewsArt",
  63                 Handler: HandleDelNewsArt,
  64         },
  65         TranDelNewsItem: {
  66                 Name:    "TranDelNewsItem",
  67                 Handler: HandleDelNewsItem,
  68         },
  69         TranDeleteFile: {
  70                 Name:    "TranDeleteFile",
  71                 Handler: HandleDeleteFile,
  72         },
  73         TranDeleteUser: {
  74                 Name:    "TranDeleteUser",
  75                 Handler: HandleDeleteUser,
  76         },
  77         TranDisconnectUser: {
  78                 Name:    "TranDisconnectUser",
  79                 Handler: HandleDisconnectUser,
  80         },
  81         TranDownloadFile: {
  82                 Name:    "TranDownloadFile",
  83                 Handler: HandleDownloadFile,
  84         },
  85         TranDownloadFldr: {
  86                 Name:    "TranDownloadFldr",
  87                 Handler: HandleDownloadFolder,
  88         },
  89         TranGetClientInfoText: {
  90                 Name:    "TranGetClientInfoText",
  91                 Handler: HandleGetClientInfoText,
  92         },
  93         TranGetFileInfo: {
  94                 Name:    "TranGetFileInfo",
  95                 Handler: HandleGetFileInfo,
  96         },
  97         TranGetFileNameList: {
  98                 Name:    "TranGetFileNameList",
  99                 Handler: HandleGetFileNameList,
 100         },
 101         TranGetMsgs: {
 102                 Name:    "TranGetMsgs",
 103                 Handler: HandleGetMsgs,
 104         },
 105         TranGetNewsArtData: {
 106                 Name:    "TranGetNewsArtData",
 107                 Handler: HandleGetNewsArtData,
 108         },
 109         TranGetNewsArtNameList: {
 110                 Name:    "TranGetNewsArtNameList",
 111                 Handler: HandleGetNewsArtNameList,
 112         },
 113         TranGetNewsCatNameList: {
 114                 Name:    "TranGetNewsCatNameList",
 115                 Handler: HandleGetNewsCatNameList,
 116         },
 117         TranGetUser: {
 118                 Name:    "TranGetUser",
 119                 Handler: HandleGetUser,
 120         },
 121         TranGetUserNameList: {
 122                 Name:    "tranHandleGetUserNameList",
 123                 Handler: HandleGetUserNameList,
 124         },
 125         TranInviteNewChat: {
 126                 Name:    "TranInviteNewChat",
 127                 Handler: HandleInviteNewChat,
 128         },
 129         TranInviteToChat: {
 130                 Name:    "TranInviteToChat",
 131                 Handler: HandleInviteToChat,
 132         },
 133         TranJoinChat: {
 134                 Name:    "TranJoinChat",
 135                 Handler: HandleJoinChat,
 136         },
 137         TranKeepAlive: {
 138                 Name:    "TranKeepAlive",
 139                 Handler: HandleKeepAlive,
 140         },
 141         TranLeaveChat: {
 142                 Name:    "TranJoinChat",
 143                 Handler: HandleLeaveChat,
 144         },
 145         TranListUsers: {
 146                 Name:    "TranListUsers",
 147                 Handler: HandleListUsers,
 148         },
 149         TranMoveFile: {
 150                 Name:    "TranMoveFile",
 151                 Handler: HandleMoveFile,
 152         },
 153         TranNewFolder: {
 154                 Name:    "TranNewFolder",
 155                 Handler: HandleNewFolder,
 156         },
 157         TranNewNewsCat: {
 158                 Name:    "TranNewNewsCat",
 159                 Handler: HandleNewNewsCat,
 160         },
 161         TranNewNewsFldr: {
 162                 Name:    "TranNewNewsFldr",
 163                 Handler: HandleNewNewsFldr,
 164         },
 165         TranNewUser: {
 166                 Name:    "TranNewUser",
 167                 Handler: HandleNewUser,
 168         },
 169         TranUpdateUser: {
 170                 Name:    "TranUpdateUser",
 171                 Handler: HandleUpdateUser,
 172         },
 173         TranOldPostNews: {
 174                 Name:    "TranOldPostNews",
 175                 Handler: HandleTranOldPostNews,
 176         },
 177         TranPostNewsArt: {
 178                 Name:    "TranPostNewsArt",
 179                 Handler: HandlePostNewsArt,
 180         },
 181         TranRejectChatInvite: {
 182                 Name:    "TranRejectChatInvite",
 183                 Handler: HandleRejectChatInvite,
 184         },
 185         TranSendInstantMsg: {
 186                 Name:    "TranSendInstantMsg",
 187                 Handler: HandleSendInstantMsg,
 188                 RequiredFields: []requiredField{
 189                         {
 190                                 ID:     FieldData,
 191                                 minLen: 0,
 192                         },
 193                         {
 194                                 ID: FieldUserID,
 195                         },
 196                 },
 197         },
 198         TranSetChatSubject: {
 199                 Name:    "TranSetChatSubject",
 200                 Handler: HandleSetChatSubject,
 201         },
 202         TranMakeFileAlias: {
 203                 Name:    "TranMakeFileAlias",
 204                 Handler: HandleMakeAlias,
 205                 RequiredFields: []requiredField{
 206                         {ID: FieldFileName, minLen: 1},
 207                         {ID: FieldFilePath, minLen: 1},
 208                         {ID: FieldFileNewPath, minLen: 1},
 209                 },
 210         },
 211         TranSetClientUserInfo: {
 212                 Name:    "TranSetClientUserInfo",
 213                 Handler: HandleSetClientUserInfo,
 214         },
 215         TranSetFileInfo: {
 216                 Name:    "TranSetFileInfo",
 217                 Handler: HandleSetFileInfo,
 218         },
 219         TranSetUser: {
 220                 Name:    "TranSetUser",
 221                 Handler: HandleSetUser,
 222         },
 223         TranUploadFile: {
 224                 Name:    "TranUploadFile",
 225                 Handler: HandleUploadFile,
 226         },
 227         TranUploadFldr: {
 228                 Name:    "TranUploadFldr",
 229                 Handler: HandleUploadFolder,
 230         },
 231         TranUserBroadcast: {
 232                 Name:    "TranUserBroadcast",
 233                 Handler: HandleUserBroadcast,
 234         },
 235         TranDownloadBanner: {
 236                 Name:    "TranDownloadBanner",
 237                 Handler: HandleDownloadBanner,
 238         },
 239 }
 240
 241 func HandleChatSend(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 242         if !cc.Authorize(accessSendChat) {
 243                 res = append(res, cc.NewErrReply(t, "You are not allowed to participate in chat."))
 244                 return res, err
 245         }
 246
 247         // Truncate long usernames
 248         trunc := fmt.Sprintf("%13s", cc.UserName)
 249         formattedMsg := fmt.Sprintf("\r%.14s:  %s", trunc, t.GetField(FieldData).Data)
 250
 251         // By holding the option key, Hotline chat allows users to send /me formatted messages like:
 252         // *** Halcyon does stuff
 253         // This is indicated by the presence of the optional field FieldChatOptions set to a value of 1.
 254         // Most clients do not send this option for normal chat messages.
 255         if t.GetField(FieldChatOptions).Data != nil && bytes.Equal(t.GetField(FieldChatOptions).Data, []byte{0, 1}) {
 256                 formattedMsg = fmt.Sprintf("\r*** %s %s", cc.UserName, t.GetField(FieldData).Data)
 257         }
 258
 259         // The ChatID field is used to identify messages as belonging to a private chat.
 260         // All clients *except* Frogblast omit this field for public chat, but Frogblast sends a value of 00 00 00 00.
 261         chatID := t.GetField(FieldChatID).Data
 262         if chatID != nil && !bytes.Equal([]byte{0, 0, 0, 0}, chatID) {
 263                 chatInt := binary.BigEndian.Uint32(chatID)
 264                 privChat := cc.Server.PrivateChats[chatInt]
 265
 266                 clients := sortedClients(privChat.ClientConn)
 267
 268                 // send the message to all connected clients of the private chat
 269                 for _, c := range clients {
 270                         res = append(res, *NewTransaction(
 271                                 TranChatMsg,
 272                                 c.ID,
 273                                 NewField(FieldChatID, chatID),
 274                                 NewField(FieldData, []byte(formattedMsg)),
 275                         ))
 276                 }
 277                 return res, err
 278         }
 279
 280         for _, c := range sortedClients(cc.Server.Clients) {
 281                 // Filter out clients that do not have the read chat permission
 282                 if c.Authorize(accessReadChat) {
 283                         res = append(res, *NewTransaction(TranChatMsg, c.ID, NewField(FieldData, []byte(formattedMsg))))
 284                 }
 285         }
 286
 287         return res, err
 288 }
 289
 290 // HandleSendInstantMsg sends instant message to the user on the current server.
 291 // Fields used in the request:
 292 //
 293 //      103     User ID
 294 //      113     Options
 295 //              One of the following values:
 296 //              - User message (myOpt_UserMessage = 1)
 297 //              - Refuse message (myOpt_RefuseMessage = 2)
 298 //              - Refuse chat (myOpt_RefuseChat  = 3)
 299 //              - Automatic response (myOpt_AutomaticResponse = 4)"
 300 //      101     Data    Optional
 301 //      214     Quoting message Optional
 302 //
 303 // Fields used in the reply:
 304 // None
 305 func HandleSendInstantMsg(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 306         if !cc.Authorize(accessSendPrivMsg) {
 307                 res = append(res, cc.NewErrReply(t, "You are not allowed to send private messages."))
 308                 return res, errors.New("user is not allowed to send private messages")
 309         }
 310
 311         msg := t.GetField(FieldData)
 312         ID := t.GetField(FieldUserID)
 313
 314         reply := NewTransaction(
 315                 TranServerMsg,
 316                 &ID.Data,
 317                 NewField(FieldData, msg.Data),
 318                 NewField(FieldUserName, cc.UserName),
 319                 NewField(FieldUserID, *cc.ID),
 320                 NewField(FieldOptions, []byte{0, 1}),
 321         )
 322
 323         // Later versions of Hotline include the original message in the FieldQuotingMsg field so
 324         //  the receiving client can display both the received message and what it is in reply to
 325         if t.GetField(FieldQuotingMsg).Data != nil {
 326                 reply.Fields = append(reply.Fields, NewField(FieldQuotingMsg, t.GetField(FieldQuotingMsg).Data))
 327         }
 328
 329         id, err := byteToInt(ID.Data)
 330         if err != nil {
 331                 return res, errors.New("invalid client ID")
 332         }
 333         otherClient, ok := cc.Server.Clients[uint16(id)]
 334         if !ok {
 335                 return res, errors.New("invalid client ID")
 336         }
 337
 338         // Check if target user has "Refuse private messages" flag
 339         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(otherClient.Flags)))
 340         if flagBitmap.Bit(UserFlagRefusePM) == 1 {
 341                 res = append(res,
 342                         *NewTransaction(
 343                                 TranServerMsg,
 344                                 cc.ID,
 345                                 NewField(FieldData, []byte(string(otherClient.UserName)+" does not accept private messages.")),
 346                                 NewField(FieldUserName, otherClient.UserName),
 347                                 NewField(FieldUserID, *otherClient.ID),
 348                                 NewField(FieldOptions, []byte{0, 2}),
 349                         ),
 350                 )
 351         } else {
 352                 res = append(res, *reply)
 353         }
 354
 355         // Respond with auto reply if other client has it enabled
 356         if len(otherClient.AutoReply) > 0 {
 357                 res = append(res,
 358                         *NewTransaction(
 359                                 TranServerMsg,
 360                                 cc.ID,
 361                                 NewField(FieldData, otherClient.AutoReply),
 362                                 NewField(FieldUserName, otherClient.UserName),
 363                                 NewField(FieldUserID, *otherClient.ID),
 364                                 NewField(FieldOptions, []byte{0, 1}),
 365                         ),
 366                 )
 367         }
 368
 369         res = append(res, cc.NewReply(t))
 370
 371         return res, err
 372 }
 373
 374 func HandleGetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 375         fileName := t.GetField(FieldFileName).Data
 376         filePath := t.GetField(FieldFilePath).Data
 377
 378         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 379         if err != nil {
 380                 return res, err
 381         }
 382
 383         fw, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 384         if err != nil {
 385                 return res, err
 386         }
 387
 388         encodedName, err := txtEncoder.String(fw.name)
 389         if err != nil {
 390                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 391         }
 392
 393         fields := []Field{
 394                 NewField(FieldFileName, []byte(encodedName)),
 395                 NewField(FieldFileTypeString, fw.ffo.FlatFileInformationFork.friendlyType()),
 396                 NewField(FieldFileCreatorString, fw.ffo.FlatFileInformationFork.friendlyCreator()),
 397                 NewField(FieldFileType, fw.ffo.FlatFileInformationFork.TypeSignature),
 398                 NewField(FieldFileCreateDate, fw.ffo.FlatFileInformationFork.CreateDate),
 399                 NewField(FieldFileModifyDate, fw.ffo.FlatFileInformationFork.ModifyDate),
 400         }
 401
 402         // Include the optional FileComment field if there is a comment.
 403         if len(fw.ffo.FlatFileInformationFork.Comment) != 0 {
 404                 fields = append(fields, NewField(FieldFileComment, fw.ffo.FlatFileInformationFork.Comment))
 405         }
 406
 407         // Include the FileSize field for files.
 408         if !bytes.Equal(fw.ffo.FlatFileInformationFork.TypeSignature, []byte{0x66, 0x6c, 0x64, 0x72}) {
 409                 fields = append(fields, NewField(FieldFileSize, fw.totalSize()))
 410         }
 411
 412         res = append(res, cc.NewReply(t, fields...))
 413         return res, err
 414 }
 415
 416 // HandleSetFileInfo updates a file or folder name and/or comment from the Get Info window
 417 // Fields used in the request:
 418 // * 201        File name
 419 // * 202        File path       Optional
 420 // * 211        File new name   Optional
 421 // * 210        File comment    Optional
 422 // Fields used in the reply:    None
 423 func HandleSetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 424         fileName := t.GetField(FieldFileName).Data
 425         filePath := t.GetField(FieldFilePath).Data
 426
 427         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 428         if err != nil {
 429                 return res, err
 430         }
 431
 432         fi, err := cc.Server.FS.Stat(fullFilePath)
 433         if err != nil {
 434                 return res, err
 435         }
 436
 437         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 438         if err != nil {
 439                 return res, err
 440         }
 441         if t.GetField(FieldFileComment).Data != nil {
 442                 switch mode := fi.Mode(); {
 443                 case mode.IsDir():
 444                         if !cc.Authorize(accessSetFolderComment) {
 445                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for folders."))
 446                                 return res, err
 447                         }
 448                 case mode.IsRegular():
 449                         if !cc.Authorize(accessSetFileComment) {
 450                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for files."))
 451                                 return res, err
 452                         }
 453                 }
 454
 455                 if err := hlFile.ffo.FlatFileInformationFork.setComment(t.GetField(FieldFileComment).Data); err != nil {
 456                         return res, err
 457                 }
 458                 w, err := hlFile.infoForkWriter()
 459                 if err != nil {
 460                         return res, err
 461                 }
 462                 _, err = w.Write(hlFile.ffo.FlatFileInformationFork.MarshalBinary())
 463                 if err != nil {
 464                         return res, err
 465                 }
 466         }
 467
 468         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, t.GetField(FieldFileNewName).Data)
 469         if err != nil {
 470                 return nil, err
 471         }
 472
 473         fileNewName := t.GetField(FieldFileNewName).Data
 474
 475         if fileNewName != nil {
 476                 switch mode := fi.Mode(); {
 477                 case mode.IsDir():
 478                         if !cc.Authorize(accessRenameFolder) {
 479                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename folders."))
 480                                 return res, err
 481                         }
 482                         err = os.Rename(fullFilePath, fullNewFilePath)
 483                         if os.IsNotExist(err) {
 484                                 res = append(res, cc.NewErrReply(t, "Cannot rename folder "+string(fileName)+" because it does not exist or cannot be found."))
 485                                 return res, err
 486                         }
 487                 case mode.IsRegular():
 488                         if !cc.Authorize(accessRenameFile) {
 489                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename files."))
 490                                 return res, err
 491                         }
 492                         fileDir, err := readPath(cc.Server.Config.FileRoot, filePath, []byte{})
 493                         if err != nil {
 494                                 return nil, err
 495                         }
 496                         hlFile.name, err = txtDecoder.String(string(fileNewName))
 497                         if err != nil {
 498                                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 499                         }
 500
 501                         err = hlFile.move(fileDir)
 502                         if os.IsNotExist(err) {
 503                                 res = append(res, cc.NewErrReply(t, "Cannot rename file "+string(fileName)+" because it does not exist or cannot be found."))
 504                                 return res, err
 505                         }
 506                         if err != nil {
 507                                 return res, err
 508                         }
 509                 }
 510         }
 511
 512         res = append(res, cc.NewReply(t))
 513         return res, err
 514 }
 515
 516 // HandleDeleteFile deletes a file or folder
 517 // Fields used in the request:
 518 // * 201        File name
 519 // * 202        File path
 520 // Fields used in the reply: none
 521 func HandleDeleteFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 522         fileName := t.GetField(FieldFileName).Data
 523         filePath := t.GetField(FieldFilePath).Data
 524
 525         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 526         if err != nil {
 527                 return res, err
 528         }
 529
 530         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 531         if err != nil {
 532                 return res, err
 533         }
 534
 535         fi, err := hlFile.dataFile()
 536         if err != nil {
 537                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+string(fileName)+" because it does not exist or cannot be found."))
 538                 return res, nil
 539         }
 540
 541         switch mode := fi.Mode(); {
 542         case mode.IsDir():
 543                 if !cc.Authorize(accessDeleteFolder) {
 544                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete folders."))
 545                         return res, err
 546                 }
 547         case mode.IsRegular():
 548                 if !cc.Authorize(accessDeleteFile) {
 549                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete files."))
 550                         return res, err
 551                 }
 552         }
 553
 554         if err := hlFile.delete(); err != nil {
 555                 return res, err
 556         }
 557
 558         res = append(res, cc.NewReply(t))
 559         return res, err
 560 }
 561
 562 // HandleMoveFile moves files or folders. Note: seemingly not documented
 563 func HandleMoveFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 564         fileName := string(t.GetField(FieldFileName).Data)
 565
 566         filePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFilePath).Data, t.GetField(FieldFileName).Data)
 567         if err != nil {
 568                 return res, err
 569         }
 570
 571         fileNewPath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFileNewPath).Data, nil)
 572         if err != nil {
 573                 return res, err
 574         }
 575
 576         cc.logger.Infow("Move file", "src", filePath+"/"+fileName, "dst", fileNewPath+"/"+fileName)
 577
 578         hlFile, err := newFileWrapper(cc.Server.FS, filePath, 0)
 579         if err != nil {
 580                 return res, err
 581         }
 582
 583         fi, err := hlFile.dataFile()
 584         if err != nil {
 585                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+fileName+" because it does not exist or cannot be found."))
 586                 return res, err
 587         }
 588         switch mode := fi.Mode(); {
 589         case mode.IsDir():
 590                 if !cc.Authorize(accessMoveFolder) {
 591                         res = append(res, cc.NewErrReply(t, "You are not allowed to move folders."))
 592                         return res, err
 593                 }
 594         case mode.IsRegular():
 595                 if !cc.Authorize(accessMoveFile) {
 596                         res = append(res, cc.NewErrReply(t, "You are not allowed to move files."))
 597                         return res, err
 598                 }
 599         }
 600         if err := hlFile.move(fileNewPath); err != nil {
 601                 return res, err
 602         }
 603         // TODO: handle other possible errors; e.g. fileWrapper delete fails due to fileWrapper permission issue
 604
 605         res = append(res, cc.NewReply(t))
 606         return res, err
 607 }
 608
 609 func HandleNewFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 610         if !cc.Authorize(accessCreateFolder) {
 611                 res = append(res, cc.NewErrReply(t, "You are not allowed to create folders."))
 612                 return res, err
 613         }
 614         folderName := string(t.GetField(FieldFileName).Data)
 615
 616         folderName = path.Join("/", folderName)
 617
 618         var subPath string
 619
 620         // FieldFilePath is only present for nested paths
 621         if t.GetField(FieldFilePath).Data != nil {
 622                 var newFp FilePath
 623                 _, err := newFp.Write(t.GetField(FieldFilePath).Data)
 624                 if err != nil {
 625                         return nil, err
 626                 }
 627
 628                 for _, pathItem := range newFp.Items {
 629                         subPath = filepath.Join("/", subPath, string(pathItem.Name))
 630                 }
 631         }
 632         newFolderPath := path.Join(cc.Server.Config.FileRoot, subPath, folderName)
 633         newFolderPath, err = txtDecoder.String(newFolderPath)
 634         if err != nil {
 635                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 636         }
 637
 638         // TODO: check path and folder name lengths
 639
 640         if _, err := cc.Server.FS.Stat(newFolderPath); !os.IsNotExist(err) {
 641                 msg := fmt.Sprintf("Cannot create folder \"%s\" because there is already a file or folder with that name.", folderName)
 642                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 643         }
 644
 645         if err := cc.Server.FS.Mkdir(newFolderPath, 0777); err != nil {
 646                 msg := fmt.Sprintf("Cannot create folder \"%s\" because an error occurred.", folderName)
 647                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 648         }
 649
 650         res = append(res, cc.NewReply(t))
 651         return res, err
 652 }
 653
 654 func HandleSetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 655         if !cc.Authorize(accessModifyUser) {
 656                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 657                 return res, err
 658         }
 659
 660         login := decodeString(t.GetField(FieldUserLogin).Data)
 661         userName := string(t.GetField(FieldUserName).Data)
 662
 663         newAccessLvl := t.GetField(FieldUserAccess).Data
 664
 665         account := cc.Server.Accounts[login]
 666         if account == nil {
 667                 return append(res, cc.NewErrReply(t, "Account not found.")), nil
 668         }
 669         account.Name = userName
 670         copy(account.Access[:], newAccessLvl)
 671
 672         // If the password field is cleared in the Hotline edit user UI, the SetUser transaction does
 673         // not include FieldUserPassword
 674         if t.GetField(FieldUserPassword).Data == nil {
 675                 account.Password = hashAndSalt([]byte(""))
 676         }
 677
 678         if !bytes.Equal([]byte{0}, t.GetField(FieldUserPassword).Data) {
 679                 account.Password = hashAndSalt(t.GetField(FieldUserPassword).Data)
 680         }
 681
 682         out, err := yaml.Marshal(&account)
 683         if err != nil {
 684                 return res, err
 685         }
 686         if err := os.WriteFile(filepath.Join(cc.Server.ConfigDir, "Users", login+".yaml"), out, 0666); err != nil {
 687                 return res, err
 688         }
 689
 690         // Notify connected clients logged in as the user of the new access level
 691         for _, c := range cc.Server.Clients {
 692                 if c.Account.Login == login {
 693                         // Note: comment out these two lines to test server-side deny messages
 694                         newT := NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, newAccessLvl))
 695                         res = append(res, *newT)
 696
 697                         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 698                         if c.Authorize(accessDisconUser) {
 699                                 flagBitmap.SetBit(flagBitmap, UserFlagAdmin, 1)
 700                         } else {
 701                                 flagBitmap.SetBit(flagBitmap, UserFlagAdmin, 0)
 702                         }
 703                         binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 704
 705                         c.Account.Access = account.Access
 706
 707                         cc.sendAll(
 708                                 TranNotifyChangeUser,
 709                                 NewField(FieldUserID, *c.ID),
 710                                 NewField(FieldUserFlags, c.Flags),
 711                                 NewField(FieldUserName, c.UserName),
 712                                 NewField(FieldUserIconID, c.Icon),
 713                         )
 714                 }
 715         }
 716
 717         res = append(res, cc.NewReply(t))
 718         return res, err
 719 }
 720
 721 func HandleGetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 722         if !cc.Authorize(accessOpenUser) {
 723                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 724                 return res, err
 725         }
 726
 727         account := cc.Server.Accounts[string(t.GetField(FieldUserLogin).Data)]
 728         if account == nil {
 729                 res = append(res, cc.NewErrReply(t, "Account does not exist."))
 730                 return res, err
 731         }
 732
 733         res = append(res, cc.NewReply(t,
 734                 NewField(FieldUserName, []byte(account.Name)),
 735                 NewField(FieldUserLogin, encodeString(t.GetField(FieldUserLogin).Data)),
 736                 NewField(FieldUserPassword, []byte(account.Password)),
 737                 NewField(FieldUserAccess, account.Access[:]),
 738         ))
 739         return res, err
 740 }
 741
 742 func HandleListUsers(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 743         if !cc.Authorize(accessOpenUser) {
 744                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 745                 return res, err
 746         }
 747
 748         var userFields []Field
 749         for _, acc := range cc.Server.Accounts {
 750                 b := make([]byte, 0, 100)
 751                 n, err := acc.Read(b)
 752                 if err != nil {
 753                         return res, err
 754                 }
 755
 756                 userFields = append(userFields, NewField(FieldData, b[:n]))
 757         }
 758
 759         res = append(res, cc.NewReply(t, userFields...))
 760         return res, err
 761 }
 762
 763 // HandleUpdateUser is used by the v1.5+ multi-user editor to perform account editing for multiple users at a time.
 764 // An update can be a mix of these actions:
 765 // * Create user
 766 // * Delete user
 767 // * Modify user (including renaming the account login)
 768 //
 769 // The Transaction sent by the client includes one data field per user that was modified.  This data field in turn
 770 // contains another data field encoded in its payload with a varying number of sub fields depending on which action is
 771 // performed.  This seems to be the only place in the Hotline protocol where a data field contains another data field.
 772 func HandleUpdateUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 773         for _, field := range t.Fields {
 774                 subFields, err := ReadFields(field.Data[0:2], field.Data[2:])
 775                 if err != nil {
 776                         return res, err
 777                 }
 778
 779                 // If there's only one subfield, that indicates this is a delete operation for the login in FieldData
 780                 if len(subFields) == 1 {
 781                         if !cc.Authorize(accessDeleteUser) {
 782                                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 783                                 return res, err
 784                         }
 785
 786                         login := decodeString(getField(FieldData, &subFields).Data)
 787                         cc.logger.Infow("DeleteUser", "login", login)
 788
 789                         if err := cc.Server.DeleteUser(login); err != nil {
 790                                 return res, err
 791                         }
 792                         continue
 793                 }
 794
 795                 // login of the account to update
 796                 var accountToUpdate, loginToRename string
 797
 798                 // If FieldData is included, this is a rename operation where FieldData contains the login of the existing
 799                 // account and FieldUserLogin contains the new login.
 800                 if getField(FieldData, &subFields) != nil {
 801                         loginToRename = decodeString(getField(FieldData, &subFields).Data)
 802                 }
 803                 userLogin := decodeString(getField(FieldUserLogin, &subFields).Data)
 804                 if loginToRename != "" {
 805                         accountToUpdate = loginToRename
 806                 } else {
 807                         accountToUpdate = userLogin
 808                 }
 809
 810                 // Check if accountToUpdate has an existing account.  If so, we know we are updating an existing user.
 811                 if acc, ok := cc.Server.Accounts[accountToUpdate]; ok {
 812                         if loginToRename != "" {
 813                                 cc.logger.Infow("RenameUser", "prevLogin", accountToUpdate, "newLogin", userLogin)
 814                         } else {
 815                                 cc.logger.Infow("UpdateUser", "login", accountToUpdate)
 816                         }
 817
 818                         // account exists, so this is an update action
 819                         if !cc.Authorize(accessModifyUser) {
 820                                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 821                                 return res, nil
 822                         }
 823
 824                         // This part is a bit tricky. There are three possibilities:
 825                         // 1) The transaction is intended to update the password.
 826                         //        In this case, FieldUserPassword is sent with the new password.
 827                         // 2) The transaction is intended to remove the password.
 828                         //    In this case, FieldUserPassword is not sent.
 829                         // 3) The transaction updates the users access bits, but not the password.
 830                         //    In this case, FieldUserPassword is sent with zero as the only byte.
 831                         if getField(FieldUserPassword, &subFields) != nil {
 832                                 newPass := getField(FieldUserPassword, &subFields).Data
 833                                 if !bytes.Equal([]byte{0}, newPass) {
 834                                         acc.Password = hashAndSalt(newPass)
 835                                 }
 836                         } else {
 837                                 acc.Password = hashAndSalt([]byte(""))
 838                         }
 839
 840                         if getField(FieldUserAccess, &subFields) != nil {
 841                                 copy(acc.Access[:], getField(FieldUserAccess, &subFields).Data)
 842                         }
 843
 844                         err = cc.Server.UpdateUser(
 845                                 decodeString(getField(FieldData, &subFields).Data),
 846                                 decodeString(getField(FieldUserLogin, &subFields).Data),
 847                                 string(getField(FieldUserName, &subFields).Data),
 848                                 acc.Password,
 849                                 acc.Access,
 850                         )
 851                         if err != nil {
 852                                 return res, err
 853                         }
 854                 } else {
 855                         if !cc.Authorize(accessCreateUser) {
 856                                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 857                                 return res, nil
 858                         }
 859
 860                         cc.logger.Infow("CreateUser", "login", userLogin)
 861
 862                         newAccess := accessBitmap{}
 863                         copy(newAccess[:], getField(FieldUserAccess, &subFields).Data)
 864
 865                         // Prevent account from creating new account with greater permission
 866                         for i := 0; i < 64; i++ {
 867                                 if newAccess.IsSet(i) {
 868                                         if !cc.Authorize(i) {
 869                                                 return append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself.")), nil
 870                                         }
 871                                 }
 872                         }
 873
 874                         err = cc.Server.NewUser(userLogin, string(getField(FieldUserName, &subFields).Data), string(getField(FieldUserPassword, &subFields).Data), newAccess)
 875                         if err != nil {
 876                                 return append(res, cc.NewErrReply(t, "Cannot create account because there is already an account with that login.")), nil
 877                         }
 878                 }
 879         }
 880
 881         res = append(res, cc.NewReply(t))
 882         return res, err
 883 }
 884
 885 // HandleNewUser creates a new user account
 886 func HandleNewUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 887         if !cc.Authorize(accessCreateUser) {
 888                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 889                 return res, err
 890         }
 891
 892         login := decodeString(t.GetField(FieldUserLogin).Data)
 893
 894         // If the account already dataFile, reply with an error
 895         if _, ok := cc.Server.Accounts[login]; ok {
 896                 res = append(res, cc.NewErrReply(t, "Cannot create account "+login+" because there is already an account with that login."))
 897                 return res, err
 898         }
 899
 900         newAccess := accessBitmap{}
 901         copy(newAccess[:], t.GetField(FieldUserAccess).Data)
 902
 903         // Prevent account from creating new account with greater permission
 904         for i := 0; i < 64; i++ {
 905                 if newAccess.IsSet(i) {
 906                         if !cc.Authorize(i) {
 907                                 res = append(res, cc.NewErrReply(t, "Cannot create account with more access than yourself."))
 908                                 return res, err
 909                         }
 910                 }
 911         }
 912
 913         if err := cc.Server.NewUser(login, string(t.GetField(FieldUserName).Data), string(t.GetField(FieldUserPassword).Data), newAccess); err != nil {
 914                 res = append(res, cc.NewErrReply(t, "Cannot create account because there is already an account with that login."))
 915                 return res, err
 916         }
 917
 918         res = append(res, cc.NewReply(t))
 919         return res, err
 920 }
 921
 922 func HandleDeleteUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 923         if !cc.Authorize(accessDeleteUser) {
 924                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 925                 return res, nil
 926         }
 927
 928         login := decodeString(t.GetField(FieldUserLogin).Data)
 929
 930         if err := cc.Server.DeleteUser(login); err != nil {
 931                 return res, err
 932         }
 933
 934         res = append(res, cc.NewReply(t))
 935         return res, err
 936 }
 937
 938 // HandleUserBroadcast sends an Administrator Message to all connected clients of the server
 939 func HandleUserBroadcast(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 940         if !cc.Authorize(accessBroadcast) {
 941                 res = append(res, cc.NewErrReply(t, "You are not allowed to send broadcast messages."))
 942                 return res, err
 943         }
 944
 945         cc.sendAll(
 946                 TranServerMsg,
 947                 NewField(FieldData, t.GetField(TranGetMsgs).Data),
 948                 NewField(FieldChatOptions, []byte{0}),
 949         )
 950
 951         res = append(res, cc.NewReply(t))
 952         return res, err
 953 }
 954
 955 // HandleGetClientInfoText returns user information for the specific user.
 956 //
 957 // Fields used in the request:
 958 // 103  User ID
 959 //
 960 // Fields used in the reply:
 961 // 102  User name
 962 // 101  Data            User info text string
 963 func HandleGetClientInfoText(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 964         if !cc.Authorize(accessGetClientInfo) {
 965                 res = append(res, cc.NewErrReply(t, "You are not allowed to get client info."))
 966                 return res, err
 967         }
 968
 969         clientID, _ := byteToInt(t.GetField(FieldUserID).Data)
 970
 971         clientConn := cc.Server.Clients[uint16(clientID)]
 972         if clientConn == nil {
 973                 return append(res, cc.NewErrReply(t, "User not found.")), err
 974         }
 975
 976         res = append(res, cc.NewReply(t,
 977                 NewField(FieldData, []byte(clientConn.String())),
 978                 NewField(FieldUserName, clientConn.UserName),
 979         ))
 980         return res, err
 981 }
 982
 983 func HandleGetUserNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 984         res = append(res, cc.NewReply(t, cc.Server.connectedUsers()...))
 985
 986         return res, err
 987 }
 988
 989 func HandleTranAgreed(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 990         if t.GetField(FieldUserName).Data != nil {
 991                 if cc.Authorize(accessAnyName) {
 992                         cc.UserName = t.GetField(FieldUserName).Data
 993                 } else {
 994                         cc.UserName = []byte(cc.Account.Name)
 995                 }
 996         }
 997
 998         cc.Icon = t.GetField(FieldUserIconID).Data
 999
1000         cc.logger = cc.logger.With("name", string(cc.UserName))
1001         cc.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(cc.Version); return i }()))
1002
1003         options := t.GetField(FieldOptions).Data
1004         optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1005
1006         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
1007
1008         // Check refuse private PM option
1009         if optBitmap.Bit(refusePM) == 1 {
1010                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePM, 1)
1011                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1012         }
1013
1014         // Check refuse private chat option
1015         if optBitmap.Bit(refuseChat) == 1 {
1016                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePChat, 1)
1017                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1018         }
1019
1020         // Check auto response
1021         if optBitmap.Bit(autoResponse) == 1 {
1022                 cc.AutoReply = t.GetField(FieldAutomaticResponse).Data
1023         } else {
1024                 cc.AutoReply = []byte{}
1025         }
1026
1027         trans := cc.notifyOthers(
1028                 *NewTransaction(
1029                         TranNotifyChangeUser, nil,
1030                         NewField(FieldUserName, cc.UserName),
1031                         NewField(FieldUserID, *cc.ID),
1032                         NewField(FieldUserIconID, cc.Icon),
1033                         NewField(FieldUserFlags, cc.Flags),
1034                 ),
1035         )
1036         res = append(res, trans...)
1037
1038         if cc.Server.Config.BannerFile != "" {
1039                 res = append(res, *NewTransaction(TranServerBanner, cc.ID, NewField(FieldBannerType, []byte("JPEG"))))
1040         }
1041
1042         res = append(res, cc.NewReply(t))
1043
1044         return res, err
1045 }
1046
1047 // HandleTranOldPostNews updates the flat news
1048 // Fields used in this request:
1049 // 101  Data
1050 func HandleTranOldPostNews(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1051         if !cc.Authorize(accessNewsPostArt) {
1052                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news."))
1053                 return res, err
1054         }
1055
1056         cc.Server.flatNewsMux.Lock()
1057         defer cc.Server.flatNewsMux.Unlock()
1058
1059         newsDateTemplate := defaultNewsDateFormat
1060         if cc.Server.Config.NewsDateFormat != "" {
1061                 newsDateTemplate = cc.Server.Config.NewsDateFormat
1062         }
1063
1064         newsTemplate := defaultNewsTemplate
1065         if cc.Server.Config.NewsDelimiter != "" {
1066                 newsTemplate = cc.Server.Config.NewsDelimiter
1067         }
1068
1069         newsPost := fmt.Sprintf(newsTemplate+"\r", cc.UserName, time.Now().Format(newsDateTemplate), t.GetField(FieldData).Data)
1070         newsPost = strings.ReplaceAll(newsPost, "\n", "\r")
1071
1072         // update news in memory
1073         cc.Server.FlatNews = append([]byte(newsPost), cc.Server.FlatNews...)
1074
1075         // update news on disk
1076         if err := cc.Server.FS.WriteFile(filepath.Join(cc.Server.ConfigDir, "MessageBoard.txt"), cc.Server.FlatNews, 0644); err != nil {
1077                 return res, err
1078         }
1079
1080         // Notify all clients of updated news
1081         cc.sendAll(
1082                 TranNewMsg,
1083                 NewField(FieldData, []byte(newsPost)),
1084         )
1085
1086         res = append(res, cc.NewReply(t))
1087         return res, err
1088 }
1089
1090 func HandleDisconnectUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1091         if !cc.Authorize(accessDisconUser) {
1092                 res = append(res, cc.NewErrReply(t, "You are not allowed to disconnect users."))
1093                 return res, err
1094         }
1095
1096         clientConn := cc.Server.Clients[binary.BigEndian.Uint16(t.GetField(FieldUserID).Data)]
1097
1098         if clientConn.Authorize(accessCannotBeDiscon) {
1099                 res = append(res, cc.NewErrReply(t, clientConn.Account.Login+" is not allowed to be disconnected."))
1100                 return res, err
1101         }
1102
1103         // If FieldOptions is set, then the client IP is banned in addition to disconnected.
1104         // 00 01 = temporary ban
1105         // 00 02 = permanent ban
1106         if t.GetField(FieldOptions).Data != nil {
1107                 switch t.GetField(FieldOptions).Data[1] {
1108                 case 1:
1109                         // send message: "You are temporarily banned on this server"
1110                         cc.logger.Infow("Disconnect & temporarily ban " + string(clientConn.UserName))
1111
1112                         res = append(res, *NewTransaction(
1113                                 TranServerMsg,
1114                                 clientConn.ID,
1115                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
1116                                 NewField(FieldChatOptions, []byte{0, 0}),
1117                         ))
1118
1119                         banUntil := time.Now().Add(tempBanDuration)
1120                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = &banUntil
1121                 case 2:
1122                         // send message: "You are permanently banned on this server"
1123                         cc.logger.Infow("Disconnect & ban " + string(clientConn.UserName))
1124
1125                         res = append(res, *NewTransaction(
1126                                 TranServerMsg,
1127                                 clientConn.ID,
1128                                 NewField(FieldData, []byte("You are permanently banned on this server")),
1129                                 NewField(FieldChatOptions, []byte{0, 0}),
1130                         ))
1131
1132                         cc.Server.banList[strings.Split(clientConn.RemoteAddr, ":")[0]] = nil
1133                 }
1134
1135                 err := cc.Server.writeBanList()
1136                 if err != nil {
1137                         return res, err
1138                 }
1139         }
1140
1141         // TODO: remove this awful hack
1142         go func() {
1143                 time.Sleep(1 * time.Second)
1144                 clientConn.Disconnect()
1145         }()
1146
1147         return append(res, cc.NewReply(t)), err
1148 }
1149
1150 // HandleGetNewsCatNameList returns a list of news categories for a path
1151 // Fields used in the request:
1152 // 325  News path       (Optional)
1153 func HandleGetNewsCatNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1154         if !cc.Authorize(accessNewsReadArt) {
1155                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1156                 return res, err
1157         }
1158
1159         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1160         cats := cc.Server.GetNewsCatByPath(pathStrs)
1161
1162         // To store the keys in slice in sorted order
1163         keys := make([]string, len(cats))
1164         i := 0
1165         for k := range cats {
1166                 keys[i] = k
1167                 i++
1168         }
1169         sort.Strings(keys)
1170
1171         var fieldData []Field
1172         for _, k := range keys {
1173                 cat := cats[k]
1174                 b, _ := cat.MarshalBinary()
1175                 fieldData = append(fieldData, NewField(
1176                         FieldNewsCatListData15,
1177                         b,
1178                 ))
1179         }
1180
1181         res = append(res, cc.NewReply(t, fieldData...))
1182         return res, err
1183 }
1184
1185 func HandleNewNewsCat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1186         if !cc.Authorize(accessNewsCreateCat) {
1187                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news categories."))
1188                 return res, err
1189         }
1190
1191         name := string(t.GetField(FieldNewsCatName).Data)
1192         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1193
1194         cats := cc.Server.GetNewsCatByPath(pathStrs)
1195         cats[name] = NewsCategoryListData15{
1196                 Name:     name,
1197                 Type:     []byte{0, 3},
1198                 Articles: map[uint32]*NewsArtData{},
1199                 SubCats:  make(map[string]NewsCategoryListData15),
1200         }
1201
1202         if err := cc.Server.writeThreadedNews(); err != nil {
1203                 return res, err
1204         }
1205         res = append(res, cc.NewReply(t))
1206         return res, err
1207 }
1208
1209 // Fields used in the request:
1210 // 322  News category name
1211 // 325  News path
1212 func HandleNewNewsFldr(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1213         if !cc.Authorize(accessNewsCreateFldr) {
1214                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news folders."))
1215                 return res, err
1216         }
1217
1218         name := string(t.GetField(FieldFileName).Data)
1219         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1220
1221         cc.logger.Infof("Creating new news folder %s", name)
1222
1223         cats := cc.Server.GetNewsCatByPath(pathStrs)
1224         cats[name] = NewsCategoryListData15{
1225                 Name:     name,
1226                 Type:     []byte{0, 2},
1227                 Articles: map[uint32]*NewsArtData{},
1228                 SubCats:  make(map[string]NewsCategoryListData15),
1229         }
1230         if err := cc.Server.writeThreadedNews(); err != nil {
1231                 return res, err
1232         }
1233         res = append(res, cc.NewReply(t))
1234         return res, err
1235 }
1236
1237 // HandleGetNewsArtData gets the list of article names at the specified news path.
1238
1239 // Fields used in the request:
1240 // 325  News path       Optional
1241
1242 // Fields used in the reply:
1243 // 321  News article list data  Optional
1244 func HandleGetNewsArtNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1245         if !cc.Authorize(accessNewsReadArt) {
1246                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1247                 return res, err
1248         }
1249         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1250
1251         var cat NewsCategoryListData15
1252         cats := cc.Server.ThreadedNews.Categories
1253
1254         for _, fp := range pathStrs {
1255                 cat = cats[fp]
1256                 cats = cats[fp].SubCats
1257         }
1258
1259         nald := cat.GetNewsArtListData()
1260
1261         res = append(res, cc.NewReply(t, NewField(FieldNewsArtListData, nald.Payload())))
1262         return res, err
1263 }
1264
1265 // HandleGetNewsArtData requests information about the specific news article.
1266 // Fields used in the request:
1267 //
1268 // Request fields
1269 // 325  News path
1270 // 326  News article ID
1271 // 327  News article data flavor
1272 //
1273 // Fields used in the reply:
1274 // 328  News article title
1275 // 329  News article poster
1276 // 330  News article date
1277 // 331  Previous article ID
1278 // 332  Next article ID
1279 // 335  Parent article ID
1280 // 336  First child article ID
1281 // 327  News article data flavor        "Should be “text/plain”
1282 // 333  News article data       Optional (if data flavor is “text/plain”)
1283 func HandleGetNewsArtData(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1284         if !cc.Authorize(accessNewsReadArt) {
1285                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1286                 return res, err
1287         }
1288
1289         var cat NewsCategoryListData15
1290         cats := cc.Server.ThreadedNews.Categories
1291
1292         for _, fp := range ReadNewsPath(t.GetField(FieldNewsPath).Data) {
1293                 cat = cats[fp]
1294                 cats = cats[fp].SubCats
1295         }
1296
1297         // The official Hotline clients will send the article ID as 2 bytes if possible, but
1298         // some third party clients such as Frogblast and Heildrun will always send 4 bytes
1299         convertedID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1300         if err != nil {
1301                 return res, err
1302         }
1303
1304         art := cat.Articles[uint32(convertedID)]
1305         if art == nil {
1306                 res = append(res, cc.NewReply(t))
1307                 return res, err
1308         }
1309
1310         res = append(res, cc.NewReply(t,
1311                 NewField(FieldNewsArtTitle, []byte(art.Title)),
1312                 NewField(FieldNewsArtPoster, []byte(art.Poster)),
1313                 NewField(FieldNewsArtDate, art.Date),
1314                 NewField(FieldNewsArtPrevArt, art.PrevArt),
1315                 NewField(FieldNewsArtNextArt, art.NextArt),
1316                 NewField(FieldNewsArtParentArt, art.ParentArt),
1317                 NewField(FieldNewsArt1stChildArt, art.FirstChildArt),
1318                 NewField(FieldNewsArtDataFlav, []byte("text/plain")),
1319                 NewField(FieldNewsArtData, []byte(art.Data)),
1320         ))
1321         return res, err
1322 }
1323
1324 // HandleDelNewsItem deletes an existing threaded news folder or category from the server.
1325 // Fields used in the request:
1326 // 325  News path
1327 // Fields used in the reply:
1328 // None
1329 func HandleDelNewsItem(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1330         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1331
1332         cats := cc.Server.ThreadedNews.Categories
1333         delName := pathStrs[len(pathStrs)-1]
1334         if len(pathStrs) > 1 {
1335                 for _, fp := range pathStrs[0 : len(pathStrs)-1] {
1336                         cats = cats[fp].SubCats
1337                 }
1338         }
1339
1340         if bytes.Equal(cats[delName].Type, []byte{0, 3}) {
1341                 if !cc.Authorize(accessNewsDeleteCat) {
1342                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news categories.")), nil
1343                 }
1344         } else {
1345                 if !cc.Authorize(accessNewsDeleteFldr) {
1346                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news folders.")), nil
1347                 }
1348         }
1349
1350         delete(cats, delName)
1351
1352         if err := cc.Server.writeThreadedNews(); err != nil {
1353                 return res, err
1354         }
1355
1356         return append(res, cc.NewReply(t)), nil
1357 }
1358
1359 func HandleDelNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1360         if !cc.Authorize(accessNewsDeleteArt) {
1361                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete news articles."))
1362                 return res, err
1363         }
1364
1365         // Request Fields
1366         // 325  News path
1367         // 326  News article ID
1368         // 337  News article – recursive delete       Delete child articles (1) or not (0)
1369         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1370         ID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1371         if err != nil {
1372                 return res, err
1373         }
1374
1375         // TODO: Delete recursive
1376         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1377
1378         catName := pathStrs[len(pathStrs)-1]
1379         cat := cats[catName]
1380
1381         delete(cat.Articles, uint32(ID))
1382
1383         cats[catName] = cat
1384         if err := cc.Server.writeThreadedNews(); err != nil {
1385                 return res, err
1386         }
1387
1388         res = append(res, cc.NewReply(t))
1389         return res, err
1390 }
1391
1392 // Request fields
1393 // 325  News path
1394 // 326  News article ID                                                 ID of the parent article?
1395 // 328  News article title
1396 // 334  News article flags
1397 // 327  News article data flavor                Currently “text/plain”
1398 // 333  News article data
1399 func HandlePostNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1400         if !cc.Authorize(accessNewsPostArt) {
1401                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news articles."))
1402                 return res, err
1403         }
1404
1405         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1406         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1407
1408         catName := pathStrs[len(pathStrs)-1]
1409         cat := cats[catName]
1410
1411         artID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1412         if err != nil {
1413                 return res, err
1414         }
1415         convertedArtID := uint32(artID)
1416         bs := make([]byte, 4)
1417         binary.BigEndian.PutUint32(bs, convertedArtID)
1418
1419         newArt := NewsArtData{
1420                 Title:         string(t.GetField(FieldNewsArtTitle).Data),
1421                 Poster:        string(cc.UserName),
1422                 Date:          toHotlineTime(time.Now()),
1423                 PrevArt:       []byte{0, 0, 0, 0},
1424                 NextArt:       []byte{0, 0, 0, 0},
1425                 ParentArt:     bs,
1426                 FirstChildArt: []byte{0, 0, 0, 0},
1427                 DataFlav:      []byte("text/plain"),
1428                 Data:          string(t.GetField(FieldNewsArtData).Data),
1429         }
1430
1431         var keys []int
1432         for k := range cat.Articles {
1433                 keys = append(keys, int(k))
1434         }
1435
1436         nextID := uint32(1)
1437         if len(keys) > 0 {
1438                 sort.Ints(keys)
1439                 prevID := uint32(keys[len(keys)-1])
1440                 nextID = prevID + 1
1441
1442                 binary.BigEndian.PutUint32(newArt.PrevArt, prevID)
1443
1444                 // Set next article ID
1445                 binary.BigEndian.PutUint32(cat.Articles[prevID].NextArt, nextID)
1446         }
1447
1448         // Update parent article with first child reply
1449         parentID := convertedArtID
1450         if parentID != 0 {
1451                 parentArt := cat.Articles[parentID]
1452
1453                 if bytes.Equal(parentArt.FirstChildArt, []byte{0, 0, 0, 0}) {
1454                         binary.BigEndian.PutUint32(parentArt.FirstChildArt, nextID)
1455                 }
1456         }
1457
1458         cat.Articles[nextID] = &newArt
1459
1460         cats[catName] = cat
1461         if err := cc.Server.writeThreadedNews(); err != nil {
1462                 return res, err
1463         }
1464
1465         res = append(res, cc.NewReply(t))
1466         return res, err
1467 }
1468
1469 // HandleGetMsgs returns the flat news data
1470 func HandleGetMsgs(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1471         if !cc.Authorize(accessNewsReadArt) {
1472                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1473                 return res, err
1474         }
1475
1476         res = append(res, cc.NewReply(t, NewField(FieldData, cc.Server.FlatNews)))
1477
1478         return res, err
1479 }
1480
1481 func HandleDownloadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1482         if !cc.Authorize(accessDownloadFile) {
1483                 res = append(res, cc.NewErrReply(t, "You are not allowed to download files."))
1484                 return res, err
1485         }
1486
1487         fileName := t.GetField(FieldFileName).Data
1488         filePath := t.GetField(FieldFilePath).Data
1489         resumeData := t.GetField(FieldFileResumeData).Data
1490
1491         var dataOffset int64
1492         var frd FileResumeData
1493         if resumeData != nil {
1494                 if err := frd.UnmarshalBinary(t.GetField(FieldFileResumeData).Data); err != nil {
1495                         return res, err
1496                 }
1497                 // TODO: handle rsrc fork offset
1498                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1499         }
1500
1501         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1502         if err != nil {
1503                 return res, err
1504         }
1505
1506         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, dataOffset)
1507         if err != nil {
1508                 return res, err
1509         }
1510
1511         xferSize := hlFile.ffo.TransferSize(0)
1512
1513         ft := cc.newFileTransfer(FileDownload, fileName, filePath, xferSize)
1514
1515         // TODO: refactor to remove this
1516         if resumeData != nil {
1517                 var frd FileResumeData
1518                 if err := frd.UnmarshalBinary(t.GetField(FieldFileResumeData).Data); err != nil {
1519                         return res, err
1520                 }
1521                 ft.fileResumeData = &frd
1522         }
1523
1524         // Optional field for when a HL v1.5+ client requests file preview
1525         // Used only for TEXT, JPEG, GIFF, BMP or PICT files
1526         // The value will always be 2
1527         if t.GetField(FieldFileTransferOptions).Data != nil {
1528                 ft.options = t.GetField(FieldFileTransferOptions).Data
1529                 xferSize = hlFile.ffo.FlatFileDataForkHeader.DataSize[:]
1530         }
1531
1532         res = append(res, cc.NewReply(t,
1533                 NewField(FieldRefNum, ft.refNum[:]),
1534                 NewField(FieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1535                 NewField(FieldTransferSize, xferSize),
1536                 NewField(FieldFileSize, hlFile.ffo.FlatFileDataForkHeader.DataSize[:]),
1537         ))
1538
1539         return res, err
1540 }
1541
1542 // Download all files from the specified folder and sub-folders
1543 func HandleDownloadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1544         if !cc.Authorize(accessDownloadFile) {
1545                 res = append(res, cc.NewErrReply(t, "You are not allowed to download folders."))
1546                 return res, err
1547         }
1548
1549         fullFilePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFilePath).Data, t.GetField(FieldFileName).Data)
1550         if err != nil {
1551                 return res, err
1552         }
1553
1554         transferSize, err := CalcTotalSize(fullFilePath)
1555         if err != nil {
1556                 return res, err
1557         }
1558         itemCount, err := CalcItemCount(fullFilePath)
1559         if err != nil {
1560                 return res, err
1561         }
1562
1563         fileTransfer := cc.newFileTransfer(FolderDownload, t.GetField(FieldFileName).Data, t.GetField(FieldFilePath).Data, transferSize)
1564
1565         var fp FilePath
1566         _, err = fp.Write(t.GetField(FieldFilePath).Data)
1567         if err != nil {
1568                 return res, err
1569         }
1570
1571         res = append(res, cc.NewReply(t,
1572                 NewField(FieldRefNum, fileTransfer.ReferenceNumber),
1573                 NewField(FieldTransferSize, transferSize),
1574                 NewField(FieldFolderItemCount, itemCount),
1575                 NewField(FieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1576         ))
1577         return res, err
1578 }
1579
1580 // Upload all files from the local folder and its subfolders to the specified path on the server
1581 // Fields used in the request
1582 // 201  File name
1583 // 202  File path
1584 // 108  transfer size   Total size of all items in the folder
1585 // 220  Folder item count
1586 // 204  File transfer options   "Optional Currently set to 1" (TODO: ??)
1587 func HandleUploadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1588         var fp FilePath
1589         if t.GetField(FieldFilePath).Data != nil {
1590                 if _, err = fp.Write(t.GetField(FieldFilePath).Data); err != nil {
1591                         return res, err
1592                 }
1593         }
1594
1595         // Handle special cases for Upload and Drop Box folders
1596         if !cc.Authorize(accessUploadAnywhere) {
1597                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1598                         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))))
1599                         return res, err
1600                 }
1601         }
1602
1603         fileTransfer := cc.newFileTransfer(FolderUpload,
1604                 t.GetField(FieldFileName).Data,
1605                 t.GetField(FieldFilePath).Data,
1606                 t.GetField(FieldTransferSize).Data,
1607         )
1608
1609         fileTransfer.FolderItemCount = t.GetField(FieldFolderItemCount).Data
1610
1611         res = append(res, cc.NewReply(t, NewField(FieldRefNum, fileTransfer.ReferenceNumber)))
1612         return res, err
1613 }
1614
1615 // HandleUploadFile
1616 // Fields used in the request:
1617 // 201  File name
1618 // 202  File path
1619 // 204  File transfer options   "Optional
1620 // Used only to resume download, currently has value 2"
1621 // 108  File transfer size      "Optional used if download is not resumed"
1622 func HandleUploadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1623         if !cc.Authorize(accessUploadFile) {
1624                 res = append(res, cc.NewErrReply(t, "You are not allowed to upload files."))
1625                 return res, err
1626         }
1627
1628         fileName := t.GetField(FieldFileName).Data
1629         filePath := t.GetField(FieldFilePath).Data
1630         transferOptions := t.GetField(FieldFileTransferOptions).Data
1631         transferSize := t.GetField(FieldTransferSize).Data // not sent for resume
1632
1633         var fp FilePath
1634         if filePath != nil {
1635                 if _, err = fp.Write(filePath); err != nil {
1636                         return res, err
1637                 }
1638         }
1639
1640         // Handle special cases for Upload and Drop Box folders
1641         if !cc.Authorize(accessUploadAnywhere) {
1642                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1643                         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))))
1644                         return res, err
1645                 }
1646         }
1647         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1648         if err != nil {
1649                 return res, err
1650         }
1651
1652         if _, err := cc.Server.FS.Stat(fullFilePath); err == nil {
1653                 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))))
1654                 return res, err
1655         }
1656
1657         ft := cc.newFileTransfer(FileUpload, fileName, filePath, transferSize)
1658
1659         replyT := cc.NewReply(t, NewField(FieldRefNum, ft.ReferenceNumber))
1660
1661         // client has requested to resume a partially transferred file
1662         if transferOptions != nil {
1663                 fileInfo, err := cc.Server.FS.Stat(fullFilePath + incompleteFileSuffix)
1664                 if err != nil {
1665                         return res, err
1666                 }
1667
1668                 offset := make([]byte, 4)
1669                 binary.BigEndian.PutUint32(offset, uint32(fileInfo.Size()))
1670
1671                 fileResumeData := NewFileResumeData([]ForkInfoList{
1672                         *NewForkInfoList(offset),
1673                 })
1674
1675                 b, _ := fileResumeData.BinaryMarshal()
1676
1677                 ft.TransferSize = offset
1678
1679                 replyT.Fields = append(replyT.Fields, NewField(FieldFileResumeData, b))
1680         }
1681
1682         res = append(res, replyT)
1683         return res, err
1684 }
1685
1686 func HandleSetClientUserInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1687         if len(t.GetField(FieldUserIconID).Data) == 4 {
1688                 cc.Icon = t.GetField(FieldUserIconID).Data[2:]
1689         } else {
1690                 cc.Icon = t.GetField(FieldUserIconID).Data
1691         }
1692         if cc.Authorize(accessAnyName) {
1693                 cc.UserName = t.GetField(FieldUserName).Data
1694         }
1695
1696         // the options field is only passed by the client versions > 1.2.3.
1697         options := t.GetField(FieldOptions).Data
1698         if options != nil {
1699                 optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1700                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
1701
1702                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePM, optBitmap.Bit(refusePM))
1703                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1704
1705                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePChat, optBitmap.Bit(refuseChat))
1706                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1707
1708                 // Check auto response
1709                 if optBitmap.Bit(autoResponse) == 1 {
1710                         cc.AutoReply = t.GetField(FieldAutomaticResponse).Data
1711                 } else {
1712                         cc.AutoReply = []byte{}
1713                 }
1714         }
1715
1716         for _, c := range sortedClients(cc.Server.Clients) {
1717                 res = append(res, *NewTransaction(
1718                         TranNotifyChangeUser,
1719                         c.ID,
1720                         NewField(FieldUserID, *cc.ID),
1721                         NewField(FieldUserIconID, cc.Icon),
1722                         NewField(FieldUserFlags, cc.Flags),
1723                         NewField(FieldUserName, cc.UserName),
1724                 ))
1725         }
1726
1727         return res, err
1728 }
1729
1730 // HandleKeepAlive responds to keepalive transactions with an empty reply
1731 // * HL 1.9.2 Client sends keepalive msg every 3 minutes
1732 // * HL 1.2.3 Client doesn't send keepalives
1733 func HandleKeepAlive(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1734         res = append(res, cc.NewReply(t))
1735
1736         return res, err
1737 }
1738
1739 func HandleGetFileNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1740         fullPath, err := readPath(
1741                 cc.Server.Config.FileRoot,
1742                 t.GetField(FieldFilePath).Data,
1743                 nil,
1744         )
1745         if err != nil {
1746                 return res, err
1747         }
1748
1749         var fp FilePath
1750         if t.GetField(FieldFilePath).Data != nil {
1751                 if _, err = fp.Write(t.GetField(FieldFilePath).Data); err != nil {
1752                         return res, err
1753                 }
1754         }
1755
1756         // Handle special case for drop box folders
1757         if fp.IsDropbox() && !cc.Authorize(accessViewDropBoxes) {
1758                 res = append(res, cc.NewErrReply(t, "You are not allowed to view drop boxes."))
1759                 return res, err
1760         }
1761
1762         fileNames, err := getFileNameList(fullPath, cc.Server.Config.IgnoreFiles)
1763         if err != nil {
1764                 return res, err
1765         }
1766
1767         res = append(res, cc.NewReply(t, fileNames...))
1768
1769         return res, err
1770 }
1771
1772 // =================================
1773 //     Hotline private chat flow
1774 // =================================
1775 // 1. ClientA sends TranInviteNewChat to server with user ID to invite
1776 // 2. Server creates new ChatID
1777 // 3. Server sends TranInviteToChat to invitee
1778 // 4. Server replies to ClientA with new Chat ID
1779 //
1780 // A dialog box pops up in the invitee client with options to accept or decline the invitation.
1781 // If Accepted is clicked:
1782 // 1. ClientB sends TranJoinChat with FieldChatID
1783
1784 // HandleInviteNewChat invites users to new private chat
1785 func HandleInviteNewChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1786         if !cc.Authorize(accessOpenChat) {
1787                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1788                 return res, err
1789         }
1790
1791         // Client to Invite
1792         targetID := t.GetField(FieldUserID).Data
1793         newChatID := cc.Server.NewPrivateChat(cc)
1794
1795         // Check if target user has "Refuse private chat" flag
1796         binary.BigEndian.Uint16(targetID)
1797         targetClient := cc.Server.Clients[binary.BigEndian.Uint16(targetID)]
1798
1799         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(targetClient.Flags)))
1800         if flagBitmap.Bit(UserFlagRefusePChat) == 1 {
1801                 res = append(res,
1802                         *NewTransaction(
1803                                 TranServerMsg,
1804                                 cc.ID,
1805                                 NewField(FieldData, []byte(string(targetClient.UserName)+" does not accept private chats.")),
1806                                 NewField(FieldUserName, targetClient.UserName),
1807                                 NewField(FieldUserID, *targetClient.ID),
1808                                 NewField(FieldOptions, []byte{0, 2}),
1809                         ),
1810                 )
1811         } else {
1812                 res = append(res,
1813                         *NewTransaction(
1814                                 TranInviteToChat,
1815                                 &targetID,
1816                                 NewField(FieldChatID, newChatID),
1817                                 NewField(FieldUserName, cc.UserName),
1818                                 NewField(FieldUserID, *cc.ID),
1819                         ),
1820                 )
1821         }
1822
1823         res = append(res,
1824                 cc.NewReply(t,
1825                         NewField(FieldChatID, newChatID),
1826                         NewField(FieldUserName, cc.UserName),
1827                         NewField(FieldUserID, *cc.ID),
1828                         NewField(FieldUserIconID, cc.Icon),
1829                         NewField(FieldUserFlags, cc.Flags),
1830                 ),
1831         )
1832
1833         return res, err
1834 }
1835
1836 func HandleInviteToChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1837         if !cc.Authorize(accessOpenChat) {
1838                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1839                 return res, err
1840         }
1841
1842         // Client to Invite
1843         targetID := t.GetField(FieldUserID).Data
1844         chatID := t.GetField(FieldChatID).Data
1845
1846         res = append(res,
1847                 *NewTransaction(
1848                         TranInviteToChat,
1849                         &targetID,
1850                         NewField(FieldChatID, chatID),
1851                         NewField(FieldUserName, cc.UserName),
1852                         NewField(FieldUserID, *cc.ID),
1853                 ),
1854         )
1855         res = append(res,
1856                 cc.NewReply(
1857                         t,
1858                         NewField(FieldChatID, chatID),
1859                         NewField(FieldUserName, cc.UserName),
1860                         NewField(FieldUserID, *cc.ID),
1861                         NewField(FieldUserIconID, cc.Icon),
1862                         NewField(FieldUserFlags, cc.Flags),
1863                 ),
1864         )
1865
1866         return res, err
1867 }
1868
1869 func HandleRejectChatInvite(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1870         chatID := t.GetField(FieldChatID).Data
1871         chatInt := binary.BigEndian.Uint32(chatID)
1872
1873         privChat := cc.Server.PrivateChats[chatInt]
1874
1875         resMsg := append(cc.UserName, []byte(" declined invitation to chat")...)
1876
1877         for _, c := range sortedClients(privChat.ClientConn) {
1878                 res = append(res,
1879                         *NewTransaction(
1880                                 TranChatMsg,
1881                                 c.ID,
1882                                 NewField(FieldChatID, chatID),
1883                                 NewField(FieldData, resMsg),
1884                         ),
1885                 )
1886         }
1887
1888         return res, err
1889 }
1890
1891 // HandleJoinChat is sent from a v1.8+ Hotline client when the joins a private chat
1892 // Fields used in the reply:
1893 // * 115        Chat subject
1894 // * 300        User name with info (Optional)
1895 // * 300        (more user names with info)
1896 func HandleJoinChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1897         chatID := t.GetField(FieldChatID).Data
1898         chatInt := binary.BigEndian.Uint32(chatID)
1899
1900         privChat := cc.Server.PrivateChats[chatInt]
1901
1902         // Send TranNotifyChatChangeUser to current members of the chat to inform of new user
1903         for _, c := range sortedClients(privChat.ClientConn) {
1904                 res = append(res,
1905                         *NewTransaction(
1906                                 TranNotifyChatChangeUser,
1907                                 c.ID,
1908                                 NewField(FieldChatID, chatID),
1909                                 NewField(FieldUserName, cc.UserName),
1910                                 NewField(FieldUserID, *cc.ID),
1911                                 NewField(FieldUserIconID, cc.Icon),
1912                                 NewField(FieldUserFlags, cc.Flags),
1913                         ),
1914                 )
1915         }
1916
1917         privChat.ClientConn[cc.uint16ID()] = cc
1918
1919         replyFields := []Field{NewField(FieldChatSubject, []byte(privChat.Subject))}
1920         for _, c := range sortedClients(privChat.ClientConn) {
1921                 user := User{
1922                         ID:    *c.ID,
1923                         Icon:  c.Icon,
1924                         Flags: c.Flags,
1925                         Name:  string(c.UserName),
1926                 }
1927
1928                 replyFields = append(replyFields, NewField(FieldUsernameWithInfo, user.Payload()))
1929         }
1930
1931         res = append(res, cc.NewReply(t, replyFields...))
1932         return res, err
1933 }
1934
1935 // HandleLeaveChat is sent from a v1.8+ Hotline client when the user exits a private chat
1936 // Fields used in the request:
1937 //   - 114      FieldChatID
1938 //
1939 // Reply is not expected.
1940 func HandleLeaveChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1941         chatID := t.GetField(FieldChatID).Data
1942         chatInt := binary.BigEndian.Uint32(chatID)
1943
1944         privChat, ok := cc.Server.PrivateChats[chatInt]
1945         if !ok {
1946                 return res, nil
1947         }
1948
1949         delete(privChat.ClientConn, cc.uint16ID())
1950
1951         // Notify members of the private chat that the user has left
1952         for _, c := range sortedClients(privChat.ClientConn) {
1953                 res = append(res,
1954                         *NewTransaction(
1955                                 TranNotifyChatDeleteUser,
1956                                 c.ID,
1957                                 NewField(FieldChatID, chatID),
1958                                 NewField(FieldUserID, *cc.ID),
1959                         ),
1960                 )
1961         }
1962
1963         return res, err
1964 }
1965
1966 // HandleSetChatSubject is sent from a v1.8+ Hotline client when the user sets a private chat subject
1967 // Fields used in the request:
1968 // * 114        Chat ID
1969 // * 115        Chat subject
1970 // Reply is not expected.
1971 func HandleSetChatSubject(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1972         chatID := t.GetField(FieldChatID).Data
1973         chatInt := binary.BigEndian.Uint32(chatID)
1974
1975         privChat := cc.Server.PrivateChats[chatInt]
1976         privChat.Subject = string(t.GetField(FieldChatSubject).Data)
1977
1978         for _, c := range sortedClients(privChat.ClientConn) {
1979                 res = append(res,
1980                         *NewTransaction(
1981                                 TranNotifyChatSubject,
1982                                 c.ID,
1983                                 NewField(FieldChatID, chatID),
1984                                 NewField(FieldChatSubject, t.GetField(FieldChatSubject).Data),
1985                         ),
1986                 )
1987         }
1988
1989         return res, err
1990 }
1991
1992 // HandleMakeAlias makes a file alias using the specified path.
1993 // Fields used in the request:
1994 // 201  File name
1995 // 202  File path
1996 // 212  File new path   Destination path
1997 //
1998 // Fields used in the reply:
1999 // None
2000 func HandleMakeAlias(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
2001         if !cc.Authorize(accessMakeAlias) {
2002                 res = append(res, cc.NewErrReply(t, "You are not allowed to make aliases."))
2003                 return res, err
2004         }
2005         fileName := t.GetField(FieldFileName).Data
2006         filePath := t.GetField(FieldFilePath).Data
2007         fileNewPath := t.GetField(FieldFileNewPath).Data
2008
2009         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
2010         if err != nil {
2011                 return res, err
2012         }
2013
2014         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, fileNewPath, fileName)
2015         if err != nil {
2016                 return res, err
2017         }
2018
2019         cc.logger.Debugw("Make alias", "src", fullFilePath, "dst", fullNewFilePath)
2020
2021         if err := cc.Server.FS.Symlink(fullFilePath, fullNewFilePath); err != nil {
2022                 res = append(res, cc.NewErrReply(t, "Error creating alias"))
2023                 return res, nil
2024         }
2025
2026         res = append(res, cc.NewReply(t))
2027         return res, err
2028 }
2029
2030 // HandleDownloadBanner handles requests for a new banner from the server
2031 // Fields used in the request:
2032 // None
2033 // Fields used in the reply:
2034 // 107  FieldRefNum                     Used later for transfer
2035 // 108  FieldTransferSize       Size of data to be downloaded
2036 func HandleDownloadBanner(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
2037         fi, err := cc.Server.FS.Stat(filepath.Join(cc.Server.ConfigDir, cc.Server.Config.BannerFile))
2038         if err != nil {
2039                 return res, err
2040         }
2041
2042         ft := cc.newFileTransfer(bannerDownload, []byte{}, []byte{}, make([]byte, 4))
2043
2044         binary.BigEndian.PutUint32(ft.TransferSize, uint32(fi.Size()))
2045
2046         res = append(res, cc.NewReply(t,
2047                 NewField(FieldRefNum, ft.refNum[:]),
2048                 NewField(FieldTransferSize, ft.TransferSize),
2049         ))
2050
2051         return res, err
2052 }