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         "io"
  10         "math/big"
  11         "os"
  12         "path"
  13         "path/filepath"
  14         "sort"
  15         "strings"
  16         "time"
  17 )
  18
  19 type HandlerFunc func(*ClientConn, *Transaction) ([]Transaction, error)
  20
  21 type TransactionType struct {
  22         Handler        HandlerFunc // function for handling the transaction type
  23         Name           string      // Name of transaction as it will appear in logging
  24         RequiredFields []requiredField
  25 }
  26
  27 var TransactionHandlers = map[uint16]TransactionType{
  28         // Server initiated
  29         TranChatMsg: {
  30                 Name: "TranChatMsg",
  31         },
  32         // Server initiated
  33         TranNotifyChangeUser: {
  34                 Name: "TranNotifyChangeUser",
  35         },
  36         TranError: {
  37                 Name: "TranError",
  38         },
  39         TranShowAgreement: {
  40                 Name: "TranShowAgreement",
  41         },
  42         TranUserAccess: {
  43                 Name: "TranUserAccess",
  44         },
  45         TranNotifyDeleteUser: {
  46                 Name: "TranNotifyDeleteUser",
  47         },
  48         TranAgreed: {
  49                 Name:    "TranAgreed",
  50                 Handler: HandleTranAgreed,
  51         },
  52         TranChatSend: {
  53                 Name:    "TranChatSend",
  54                 Handler: HandleChatSend,
  55                 RequiredFields: []requiredField{
  56                         {
  57                                 ID:     FieldData,
  58                                 minLen: 0,
  59                         },
  60                 },
  61         },
  62         TranDelNewsArt: {
  63                 Name:    "TranDelNewsArt",
  64                 Handler: HandleDelNewsArt,
  65         },
  66         TranDelNewsItem: {
  67                 Name:    "TranDelNewsItem",
  68                 Handler: HandleDelNewsItem,
  69         },
  70         TranDeleteFile: {
  71                 Name:    "TranDeleteFile",
  72                 Handler: HandleDeleteFile,
  73         },
  74         TranDeleteUser: {
  75                 Name:    "TranDeleteUser",
  76                 Handler: HandleDeleteUser,
  77         },
  78         TranDisconnectUser: {
  79                 Name:    "TranDisconnectUser",
  80                 Handler: HandleDisconnectUser,
  81         },
  82         TranDownloadFile: {
  83                 Name:    "TranDownloadFile",
  84                 Handler: HandleDownloadFile,
  85         },
  86         TranDownloadFldr: {
  87                 Name:    "TranDownloadFldr",
  88                 Handler: HandleDownloadFolder,
  89         },
  90         TranGetClientInfoText: {
  91                 Name:    "TranGetClientInfoText",
  92                 Handler: HandleGetClientInfoText,
  93         },
  94         TranGetFileInfo: {
  95                 Name:    "TranGetFileInfo",
  96                 Handler: HandleGetFileInfo,
  97         },
  98         TranGetFileNameList: {
  99                 Name:    "TranGetFileNameList",
 100                 Handler: HandleGetFileNameList,
 101         },
 102         TranGetMsgs: {
 103                 Name:    "TranGetMsgs",
 104                 Handler: HandleGetMsgs,
 105         },
 106         TranGetNewsArtData: {
 107                 Name:    "TranGetNewsArtData",
 108                 Handler: HandleGetNewsArtData,
 109         },
 110         TranGetNewsArtNameList: {
 111                 Name:    "TranGetNewsArtNameList",
 112                 Handler: HandleGetNewsArtNameList,
 113         },
 114         TranGetNewsCatNameList: {
 115                 Name:    "TranGetNewsCatNameList",
 116                 Handler: HandleGetNewsCatNameList,
 117         },
 118         TranGetUser: {
 119                 Name:    "TranGetUser",
 120                 Handler: HandleGetUser,
 121         },
 122         TranGetUserNameList: {
 123                 Name:    "tranHandleGetUserNameList",
 124                 Handler: HandleGetUserNameList,
 125         },
 126         TranInviteNewChat: {
 127                 Name:    "TranInviteNewChat",
 128                 Handler: HandleInviteNewChat,
 129         },
 130         TranInviteToChat: {
 131                 Name:    "TranInviteToChat",
 132                 Handler: HandleInviteToChat,
 133         },
 134         TranJoinChat: {
 135                 Name:    "TranJoinChat",
 136                 Handler: HandleJoinChat,
 137         },
 138         TranKeepAlive: {
 139                 Name:    "TranKeepAlive",
 140                 Handler: HandleKeepAlive,
 141         },
 142         TranLeaveChat: {
 143                 Name:    "TranJoinChat",
 144                 Handler: HandleLeaveChat,
 145         },
 146         TranListUsers: {
 147                 Name:    "TranListUsers",
 148                 Handler: HandleListUsers,
 149         },
 150         TranMoveFile: {
 151                 Name:    "TranMoveFile",
 152                 Handler: HandleMoveFile,
 153         },
 154         TranNewFolder: {
 155                 Name:    "TranNewFolder",
 156                 Handler: HandleNewFolder,
 157         },
 158         TranNewNewsCat: {
 159                 Name:    "TranNewNewsCat",
 160                 Handler: HandleNewNewsCat,
 161         },
 162         TranNewNewsFldr: {
 163                 Name:    "TranNewNewsFldr",
 164                 Handler: HandleNewNewsFldr,
 165         },
 166         TranNewUser: {
 167                 Name:    "TranNewUser",
 168                 Handler: HandleNewUser,
 169         },
 170         TranUpdateUser: {
 171                 Name:    "TranUpdateUser",
 172                 Handler: HandleUpdateUser,
 173         },
 174         TranOldPostNews: {
 175                 Name:    "TranOldPostNews",
 176                 Handler: HandleTranOldPostNews,
 177         },
 178         TranPostNewsArt: {
 179                 Name:    "TranPostNewsArt",
 180                 Handler: HandlePostNewsArt,
 181         },
 182         TranRejectChatInvite: {
 183                 Name:    "TranRejectChatInvite",
 184                 Handler: HandleRejectChatInvite,
 185         },
 186         TranSendInstantMsg: {
 187                 Name:    "TranSendInstantMsg",
 188                 Handler: HandleSendInstantMsg,
 189                 RequiredFields: []requiredField{
 190                         {
 191                                 ID:     FieldData,
 192                                 minLen: 0,
 193                         },
 194                         {
 195                                 ID: FieldUserID,
 196                         },
 197                 },
 198         },
 199         TranSetChatSubject: {
 200                 Name:    "TranSetChatSubject",
 201                 Handler: HandleSetChatSubject,
 202         },
 203         TranMakeFileAlias: {
 204                 Name:    "TranMakeFileAlias",
 205                 Handler: HandleMakeAlias,
 206                 RequiredFields: []requiredField{
 207                         {ID: FieldFileName, minLen: 1},
 208                         {ID: FieldFilePath, minLen: 1},
 209                         {ID: FieldFileNewPath, minLen: 1},
 210                 },
 211         },
 212         TranSetClientUserInfo: {
 213                 Name:    "TranSetClientUserInfo",
 214                 Handler: HandleSetClientUserInfo,
 215         },
 216         TranSetFileInfo: {
 217                 Name:    "TranSetFileInfo",
 218                 Handler: HandleSetFileInfo,
 219         },
 220         TranSetUser: {
 221                 Name:    "TranSetUser",
 222                 Handler: HandleSetUser,
 223         },
 224         TranUploadFile: {
 225                 Name:    "TranUploadFile",
 226                 Handler: HandleUploadFile,
 227         },
 228         TranUploadFldr: {
 229                 Name:    "TranUploadFldr",
 230                 Handler: HandleUploadFolder,
 231         },
 232         TranUserBroadcast: {
 233                 Name:    "TranUserBroadcast",
 234                 Handler: HandleUserBroadcast,
 235         },
 236         TranDownloadBanner: {
 237                 Name:    "TranDownloadBanner",
 238                 Handler: HandleDownloadBanner,
 239         },
 240 }
 241
 242 func HandleChatSend(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 243         if !cc.Authorize(accessSendChat) {
 244                 res = append(res, cc.NewErrReply(t, "You are not allowed to participate in chat."))
 245                 return res, err
 246         }
 247
 248         // Truncate long usernames
 249         trunc := fmt.Sprintf("%13s", cc.UserName)
 250         formattedMsg := fmt.Sprintf("\r%.14s:  %s", trunc, t.GetField(FieldData).Data)
 251
 252         // By holding the option key, Hotline chat allows users to send /me formatted messages like:
 253         // *** Halcyon does stuff
 254         // This is indicated by the presence of the optional field FieldChatOptions set to a value of 1.
 255         // Most clients do not send this option for normal chat messages.
 256         if t.GetField(FieldChatOptions).Data != nil && bytes.Equal(t.GetField(FieldChatOptions).Data, []byte{0, 1}) {
 257                 formattedMsg = fmt.Sprintf("\r*** %s %s", cc.UserName, t.GetField(FieldData).Data)
 258         }
 259
 260         // The ChatID field is used to identify messages as belonging to a private chat.
 261         // All clients *except* Frogblast omit this field for public chat, but Frogblast sends a value of 00 00 00 00.
 262         chatID := t.GetField(FieldChatID).Data
 263         if chatID != nil && !bytes.Equal([]byte{0, 0, 0, 0}, chatID) {
 264                 chatInt := binary.BigEndian.Uint32(chatID)
 265                 privChat := cc.Server.PrivateChats[chatInt]
 266
 267                 clients := sortedClients(privChat.ClientConn)
 268
 269                 // send the message to all connected clients of the private chat
 270                 for _, c := range clients {
 271                         res = append(res, *NewTransaction(
 272                                 TranChatMsg,
 273                                 c.ID,
 274                                 NewField(FieldChatID, chatID),
 275                                 NewField(FieldData, []byte(formattedMsg)),
 276                         ))
 277                 }
 278                 return res, err
 279         }
 280
 281         for _, c := range sortedClients(cc.Server.Clients) {
 282                 // Filter out clients that do not have the read chat permission
 283                 if c.Authorize(accessReadChat) {
 284                         res = append(res, *NewTransaction(TranChatMsg, c.ID, NewField(FieldData, []byte(formattedMsg))))
 285                 }
 286         }
 287
 288         return res, err
 289 }
 290
 291 // HandleSendInstantMsg sends instant message to the user on the current server.
 292 // Fields used in the request:
 293 //
 294 //      103     User ID
 295 //      113     Options
 296 //              One of the following values:
 297 //              - User message (myOpt_UserMessage = 1)
 298 //              - Refuse message (myOpt_RefuseMessage = 2)
 299 //              - Refuse chat (myOpt_RefuseChat  = 3)
 300 //              - Automatic response (myOpt_AutomaticResponse = 4)"
 301 //      101     Data    Optional
 302 //      214     Quoting message Optional
 303 //
 304 // Fields used in the reply:
 305 // None
 306 func HandleSendInstantMsg(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 307         if !cc.Authorize(accessSendPrivMsg) {
 308                 res = append(res, cc.NewErrReply(t, "You are not allowed to send private messages."))
 309                 return res, errors.New("user is not allowed to send private messages")
 310         }
 311
 312         msg := t.GetField(FieldData)
 313         ID := t.GetField(FieldUserID)
 314
 315         reply := NewTransaction(
 316                 TranServerMsg,
 317                 &ID.Data,
 318                 NewField(FieldData, msg.Data),
 319                 NewField(FieldUserName, cc.UserName),
 320                 NewField(FieldUserID, *cc.ID),
 321                 NewField(FieldOptions, []byte{0, 1}),
 322         )
 323
 324         // Later versions of Hotline include the original message in the FieldQuotingMsg field so
 325         //  the receiving client can display both the received message and what it is in reply to
 326         if t.GetField(FieldQuotingMsg).Data != nil {
 327                 reply.Fields = append(reply.Fields, NewField(FieldQuotingMsg, t.GetField(FieldQuotingMsg).Data))
 328         }
 329
 330         id, err := byteToInt(ID.Data)
 331         if err != nil {
 332                 return res, errors.New("invalid client ID")
 333         }
 334         otherClient, ok := cc.Server.Clients[uint16(id)]
 335         if !ok {
 336                 return res, errors.New("invalid client ID")
 337         }
 338
 339         // Check if target user has "Refuse private messages" flag
 340         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(otherClient.Flags)))
 341         if flagBitmap.Bit(UserFlagRefusePM) == 1 {
 342                 res = append(res,
 343                         *NewTransaction(
 344                                 TranServerMsg,
 345                                 cc.ID,
 346                                 NewField(FieldData, []byte(string(otherClient.UserName)+" does not accept private messages.")),
 347                                 NewField(FieldUserName, otherClient.UserName),
 348                                 NewField(FieldUserID, *otherClient.ID),
 349                                 NewField(FieldOptions, []byte{0, 2}),
 350                         ),
 351                 )
 352         } else {
 353                 res = append(res, *reply)
 354         }
 355
 356         // Respond with auto reply if other client has it enabled
 357         if len(otherClient.AutoReply) > 0 {
 358                 res = append(res,
 359                         *NewTransaction(
 360                                 TranServerMsg,
 361                                 cc.ID,
 362                                 NewField(FieldData, otherClient.AutoReply),
 363                                 NewField(FieldUserName, otherClient.UserName),
 364                                 NewField(FieldUserID, *otherClient.ID),
 365                                 NewField(FieldOptions, []byte{0, 1}),
 366                         ),
 367                 )
 368         }
 369
 370         res = append(res, cc.NewReply(t))
 371
 372         return res, err
 373 }
 374
 375 func HandleGetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 376         fileName := t.GetField(FieldFileName).Data
 377         filePath := t.GetField(FieldFilePath).Data
 378
 379         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 380         if err != nil {
 381                 return res, err
 382         }
 383
 384         fw, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 385         if err != nil {
 386                 return res, err
 387         }
 388
 389         encodedName, err := txtEncoder.String(fw.name)
 390         if err != nil {
 391                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 392         }
 393
 394         fields := []Field{
 395                 NewField(FieldFileName, []byte(encodedName)),
 396                 NewField(FieldFileTypeString, fw.ffo.FlatFileInformationFork.friendlyType()),
 397                 NewField(FieldFileCreatorString, fw.ffo.FlatFileInformationFork.friendlyCreator()),
 398                 NewField(FieldFileType, fw.ffo.FlatFileInformationFork.TypeSignature),
 399                 NewField(FieldFileCreateDate, fw.ffo.FlatFileInformationFork.CreateDate),
 400                 NewField(FieldFileModifyDate, fw.ffo.FlatFileInformationFork.ModifyDate),
 401         }
 402
 403         // Include the optional FileComment field if there is a comment.
 404         if len(fw.ffo.FlatFileInformationFork.Comment) != 0 {
 405                 fields = append(fields, NewField(FieldFileComment, fw.ffo.FlatFileInformationFork.Comment))
 406         }
 407
 408         // Include the FileSize field for files.
 409         if !bytes.Equal(fw.ffo.FlatFileInformationFork.TypeSignature, []byte{0x66, 0x6c, 0x64, 0x72}) {
 410                 fields = append(fields, NewField(FieldFileSize, fw.totalSize()))
 411         }
 412
 413         res = append(res, cc.NewReply(t, fields...))
 414         return res, err
 415 }
 416
 417 // HandleSetFileInfo updates a file or folder name and/or comment from the Get Info window
 418 // Fields used in the request:
 419 // * 201        File name
 420 // * 202        File path       Optional
 421 // * 211        File new name   Optional
 422 // * 210        File comment    Optional
 423 // Fields used in the reply:    None
 424 func HandleSetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 425         fileName := t.GetField(FieldFileName).Data
 426         filePath := t.GetField(FieldFilePath).Data
 427
 428         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 429         if err != nil {
 430                 return res, err
 431         }
 432
 433         fi, err := cc.Server.FS.Stat(fullFilePath)
 434         if err != nil {
 435                 return res, err
 436         }
 437
 438         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 439         if err != nil {
 440                 return res, err
 441         }
 442         if t.GetField(FieldFileComment).Data != nil {
 443                 switch mode := fi.Mode(); {
 444                 case mode.IsDir():
 445                         if !cc.Authorize(accessSetFolderComment) {
 446                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for folders."))
 447                                 return res, err
 448                         }
 449                 case mode.IsRegular():
 450                         if !cc.Authorize(accessSetFileComment) {
 451                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for files."))
 452                                 return res, err
 453                         }
 454                 }
 455
 456                 if err := hlFile.ffo.FlatFileInformationFork.setComment(t.GetField(FieldFileComment).Data); err != nil {
 457                         return res, err
 458                 }
 459                 w, err := hlFile.infoForkWriter()
 460                 if err != nil {
 461                         return res, err
 462                 }
 463                 _, err = io.Copy(w, &hlFile.ffo.FlatFileInformationFork)
 464                 if err != nil {
 465                         return res, err
 466                 }
 467         }
 468
 469         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, t.GetField(FieldFileNewName).Data)
 470         if err != nil {
 471                 return nil, err
 472         }
 473
 474         fileNewName := t.GetField(FieldFileNewName).Data
 475
 476         if fileNewName != nil {
 477                 switch mode := fi.Mode(); {
 478                 case mode.IsDir():
 479                         if !cc.Authorize(accessRenameFolder) {
 480                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename folders."))
 481                                 return res, err
 482                         }
 483                         err = os.Rename(fullFilePath, fullNewFilePath)
 484                         if os.IsNotExist(err) {
 485                                 res = append(res, cc.NewErrReply(t, "Cannot rename folder "+string(fileName)+" because it does not exist or cannot be found."))
 486                                 return res, err
 487                         }
 488                 case mode.IsRegular():
 489                         if !cc.Authorize(accessRenameFile) {
 490                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename files."))
 491                                 return res, err
 492                         }
 493                         fileDir, err := readPath(cc.Server.Config.FileRoot, filePath, []byte{})
 494                         if err != nil {
 495                                 return nil, err
 496                         }
 497                         hlFile.name, err = txtDecoder.String(string(fileNewName))
 498                         if err != nil {
 499                                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 500                         }
 501
 502                         err = hlFile.move(fileDir)
 503                         if os.IsNotExist(err) {
 504                                 res = append(res, cc.NewErrReply(t, "Cannot rename file "+string(fileName)+" because it does not exist or cannot be found."))
 505                                 return res, err
 506                         }
 507                         if err != nil {
 508                                 return res, err
 509                         }
 510                 }
 511         }
 512
 513         res = append(res, cc.NewReply(t))
 514         return res, err
 515 }
 516
 517 // HandleDeleteFile deletes a file or folder
 518 // Fields used in the request:
 519 // * 201        File name
 520 // * 202        File path
 521 // Fields used in the reply: none
 522 func HandleDeleteFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 523         fileName := t.GetField(FieldFileName).Data
 524         filePath := t.GetField(FieldFilePath).Data
 525
 526         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 527         if err != nil {
 528                 return res, err
 529         }
 530
 531         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 532         if err != nil {
 533                 return res, err
 534         }
 535
 536         fi, err := hlFile.dataFile()
 537         if err != nil {
 538                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+string(fileName)+" because it does not exist or cannot be found."))
 539                 return res, nil
 540         }
 541
 542         switch mode := fi.Mode(); {
 543         case mode.IsDir():
 544                 if !cc.Authorize(accessDeleteFolder) {
 545                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete folders."))
 546                         return res, err
 547                 }
 548         case mode.IsRegular():
 549                 if !cc.Authorize(accessDeleteFile) {
 550                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete files."))
 551                         return res, err
 552                 }
 553         }
 554
 555         if err := hlFile.delete(); err != nil {
 556                 return res, err
 557         }
 558
 559         res = append(res, cc.NewReply(t))
 560         return res, err
 561 }
 562
 563 // HandleMoveFile moves files or folders. Note: seemingly not documented
 564 func HandleMoveFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 565         fileName := string(t.GetField(FieldFileName).Data)
 566
 567         filePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFilePath).Data, t.GetField(FieldFileName).Data)
 568         if err != nil {
 569                 return res, err
 570         }
 571
 572         fileNewPath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFileNewPath).Data, nil)
 573         if err != nil {
 574                 return res, err
 575         }
 576
 577         cc.logger.Infow("Move file", "src", filePath+"/"+fileName, "dst", fileNewPath+"/"+fileName)
 578
 579         hlFile, err := newFileWrapper(cc.Server.FS, filePath, 0)
 580         if err != nil {
 581                 return res, err
 582         }
 583
 584         fi, err := hlFile.dataFile()
 585         if err != nil {
 586                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+fileName+" because it does not exist or cannot be found."))
 587                 return res, err
 588         }
 589         switch mode := fi.Mode(); {
 590         case mode.IsDir():
 591                 if !cc.Authorize(accessMoveFolder) {
 592                         res = append(res, cc.NewErrReply(t, "You are not allowed to move folders."))
 593                         return res, err
 594                 }
 595         case mode.IsRegular():
 596                 if !cc.Authorize(accessMoveFile) {
 597                         res = append(res, cc.NewErrReply(t, "You are not allowed to move files."))
 598                         return res, err
 599                 }
 600         }
 601         if err := hlFile.move(fileNewPath); err != nil {
 602                 return res, err
 603         }
 604         // TODO: handle other possible errors; e.g. fileWrapper delete fails due to fileWrapper permission issue
 605
 606         res = append(res, cc.NewReply(t))
 607         return res, err
 608 }
 609
 610 func HandleNewFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 611         if !cc.Authorize(accessCreateFolder) {
 612                 res = append(res, cc.NewErrReply(t, "You are not allowed to create folders."))
 613                 return res, err
 614         }
 615         folderName := string(t.GetField(FieldFileName).Data)
 616
 617         folderName = path.Join("/", folderName)
 618
 619         var subPath string
 620
 621         // FieldFilePath is only present for nested paths
 622         if t.GetField(FieldFilePath).Data != nil {
 623                 var newFp FilePath
 624                 _, err := newFp.Write(t.GetField(FieldFilePath).Data)
 625                 if err != nil {
 626                         return nil, err
 627                 }
 628
 629                 for _, pathItem := range newFp.Items {
 630                         subPath = filepath.Join("/", subPath, string(pathItem.Name))
 631                 }
 632         }
 633         newFolderPath := path.Join(cc.Server.Config.FileRoot, subPath, folderName)
 634         newFolderPath, err = txtDecoder.String(newFolderPath)
 635         if err != nil {
 636                 return res, fmt.Errorf("invalid filepath encoding: %w", err)
 637         }
 638
 639         // TODO: check path and folder name lengths
 640
 641         if _, err := cc.Server.FS.Stat(newFolderPath); !os.IsNotExist(err) {
 642                 msg := fmt.Sprintf("Cannot create folder \"%s\" because there is already a file or folder with that name.", folderName)
 643                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 644         }
 645
 646         if err := cc.Server.FS.Mkdir(newFolderPath, 0777); err != nil {
 647                 msg := fmt.Sprintf("Cannot create folder \"%s\" because an error occurred.", folderName)
 648                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 649         }
 650
 651         res = append(res, cc.NewReply(t))
 652         return res, err
 653 }
 654
 655 func HandleSetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 656         if !cc.Authorize(accessModifyUser) {
 657                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 658                 return res, err
 659         }
 660
 661         login := decodeString(t.GetField(FieldUserLogin).Data)
 662         userName := string(t.GetField(FieldUserName).Data)
 663
 664         newAccessLvl := t.GetField(FieldUserAccess).Data
 665
 666         account := cc.Server.Accounts[login]
 667         if account == nil {
 668                 return append(res, cc.NewErrReply(t, "Account not found.")), nil
 669         }
 670         account.Name = userName
 671         copy(account.Access[:], newAccessLvl)
 672
 673         // If the password field is cleared in the Hotline edit user UI, the SetUser transaction does
 674         // not include FieldUserPassword
 675         if t.GetField(FieldUserPassword).Data == nil {
 676                 account.Password = hashAndSalt([]byte(""))
 677         }
 678
 679         if !bytes.Equal([]byte{0}, t.GetField(FieldUserPassword).Data) {
 680                 account.Password = hashAndSalt(t.GetField(FieldUserPassword).Data)
 681         }
 682
 683         out, err := yaml.Marshal(&account)
 684         if err != nil {
 685                 return res, err
 686         }
 687         if err := os.WriteFile(filepath.Join(cc.Server.ConfigDir, "Users", login+".yaml"), out, 0666); err != nil {
 688                 return res, err
 689         }
 690
 691         // Notify connected clients logged in as the user of the new access level
 692         for _, c := range cc.Server.Clients {
 693                 if c.Account.Login == login {
 694                         // Note: comment out these two lines to test server-side deny messages
 695                         newT := NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, newAccessLvl))
 696                         res = append(res, *newT)
 697
 698                         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 699                         if c.Authorize(accessDisconUser) {
 700                                 flagBitmap.SetBit(flagBitmap, UserFlagAdmin, 1)
 701                         } else {
 702                                 flagBitmap.SetBit(flagBitmap, UserFlagAdmin, 0)
 703                         }
 704                         binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 705
 706                         c.Account.Access = account.Access
 707
 708                         cc.sendAll(
 709                                 TranNotifyChangeUser,
 710                                 NewField(FieldUserID, *c.ID),
 711                                 NewField(FieldUserFlags, c.Flags),
 712                                 NewField(FieldUserName, c.UserName),
 713                                 NewField(FieldUserIconID, c.Icon),
 714                         )
 715                 }
 716         }
 717
 718         res = append(res, cc.NewReply(t))
 719         return res, err
 720 }
 721
 722 func HandleGetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 723         if !cc.Authorize(accessOpenUser) {
 724                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 725                 return res, err
 726         }
 727
 728         account := cc.Server.Accounts[string(t.GetField(FieldUserLogin).Data)]
 729         if account == nil {
 730                 res = append(res, cc.NewErrReply(t, "Account does not exist."))
 731                 return res, err
 732         }
 733
 734         res = append(res, cc.NewReply(t,
 735                 NewField(FieldUserName, []byte(account.Name)),
 736                 NewField(FieldUserLogin, encodeString(t.GetField(FieldUserLogin).Data)),
 737                 NewField(FieldUserPassword, []byte(account.Password)),
 738                 NewField(FieldUserAccess, account.Access[:]),
 739         ))
 740         return res, err
 741 }
 742
 743 func HandleListUsers(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 744         if !cc.Authorize(accessOpenUser) {
 745                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 746                 return res, err
 747         }
 748
 749         var userFields []Field
 750         for _, acc := range cc.Server.Accounts {
 751                 b, err := io.ReadAll(acc)
 752                 if err != nil {
 753                         return res, err
 754                 }
 755
 756                 userFields = append(userFields, NewField(FieldData, b))
 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:     [2]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:     [2]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         b, err := io.ReadAll(&nald)
1262         if err != nil {
1263
1264         }
1265
1266         res = append(res, cc.NewReply(t, NewField(FieldNewsArtListData, b)))
1267         return res, err
1268 }
1269
1270 // HandleGetNewsArtData requests information about the specific news article.
1271 // Fields used in the request:
1272 //
1273 // Request fields
1274 // 325  News path
1275 // 326  News article ID
1276 // 327  News article data flavor
1277 //
1278 // Fields used in the reply:
1279 // 328  News article title
1280 // 329  News article poster
1281 // 330  News article date
1282 // 331  Previous article ID
1283 // 332  Next article ID
1284 // 335  Parent article ID
1285 // 336  First child article ID
1286 // 327  News article data flavor        "Should be “text/plain”
1287 // 333  News article data       Optional (if data flavor is “text/plain”)
1288 func HandleGetNewsArtData(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1289         if !cc.Authorize(accessNewsReadArt) {
1290                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1291                 return res, err
1292         }
1293
1294         var cat NewsCategoryListData15
1295         cats := cc.Server.ThreadedNews.Categories
1296
1297         for _, fp := range ReadNewsPath(t.GetField(FieldNewsPath).Data) {
1298                 cat = cats[fp]
1299                 cats = cats[fp].SubCats
1300         }
1301
1302         // The official Hotline clients will send the article ID as 2 bytes if possible, but
1303         // some third party clients such as Frogblast and Heildrun will always send 4 bytes
1304         convertedID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1305         if err != nil {
1306                 return res, err
1307         }
1308
1309         art := cat.Articles[uint32(convertedID)]
1310         if art == nil {
1311                 res = append(res, cc.NewReply(t))
1312                 return res, err
1313         }
1314
1315         res = append(res, cc.NewReply(t,
1316                 NewField(FieldNewsArtTitle, []byte(art.Title)),
1317                 NewField(FieldNewsArtPoster, []byte(art.Poster)),
1318                 NewField(FieldNewsArtDate, art.Date),
1319                 NewField(FieldNewsArtPrevArt, art.PrevArt),
1320                 NewField(FieldNewsArtNextArt, art.NextArt),
1321                 NewField(FieldNewsArtParentArt, art.ParentArt),
1322                 NewField(FieldNewsArt1stChildArt, art.FirstChildArt),
1323                 NewField(FieldNewsArtDataFlav, []byte("text/plain")),
1324                 NewField(FieldNewsArtData, []byte(art.Data)),
1325         ))
1326         return res, err
1327 }
1328
1329 // HandleDelNewsItem deletes an existing threaded news folder or category from the server.
1330 // Fields used in the request:
1331 // 325  News path
1332 // Fields used in the reply:
1333 // None
1334 func HandleDelNewsItem(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1335         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1336
1337         cats := cc.Server.ThreadedNews.Categories
1338         delName := pathStrs[len(pathStrs)-1]
1339         if len(pathStrs) > 1 {
1340                 for _, fp := range pathStrs[0 : len(pathStrs)-1] {
1341                         cats = cats[fp].SubCats
1342                 }
1343         }
1344
1345         if cats[delName].Type == [2]byte{0, 3} {
1346                 if !cc.Authorize(accessNewsDeleteCat) {
1347                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news categories.")), nil
1348                 }
1349         } else {
1350                 if !cc.Authorize(accessNewsDeleteFldr) {
1351                         return append(res, cc.NewErrReply(t, "You are not allowed to delete news folders.")), nil
1352                 }
1353         }
1354
1355         delete(cats, delName)
1356
1357         if err := cc.Server.writeThreadedNews(); err != nil {
1358                 return res, err
1359         }
1360
1361         return append(res, cc.NewReply(t)), nil
1362 }
1363
1364 func HandleDelNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1365         if !cc.Authorize(accessNewsDeleteArt) {
1366                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete news articles."))
1367                 return res, err
1368         }
1369
1370         // Request Fields
1371         // 325  News path
1372         // 326  News article ID
1373         // 337  News article – recursive delete       Delete child articles (1) or not (0)
1374         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1375         ID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1376         if err != nil {
1377                 return res, err
1378         }
1379
1380         // TODO: Delete recursive
1381         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1382
1383         catName := pathStrs[len(pathStrs)-1]
1384         cat := cats[catName]
1385
1386         delete(cat.Articles, uint32(ID))
1387
1388         cats[catName] = cat
1389         if err := cc.Server.writeThreadedNews(); err != nil {
1390                 return res, err
1391         }
1392
1393         res = append(res, cc.NewReply(t))
1394         return res, err
1395 }
1396
1397 // Request fields
1398 // 325  News path
1399 // 326  News article ID                                                 ID of the parent article?
1400 // 328  News article title
1401 // 334  News article flags
1402 // 327  News article data flavor                Currently “text/plain”
1403 // 333  News article data
1404 func HandlePostNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1405         if !cc.Authorize(accessNewsPostArt) {
1406                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news articles."))
1407                 return res, err
1408         }
1409
1410         pathStrs := ReadNewsPath(t.GetField(FieldNewsPath).Data)
1411         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1412
1413         catName := pathStrs[len(pathStrs)-1]
1414         cat := cats[catName]
1415
1416         artID, err := byteToInt(t.GetField(FieldNewsArtID).Data)
1417         if err != nil {
1418                 return res, err
1419         }
1420         convertedArtID := uint32(artID)
1421         bs := make([]byte, 4)
1422         binary.BigEndian.PutUint32(bs, convertedArtID)
1423
1424         newArt := NewsArtData{
1425                 Title:         string(t.GetField(FieldNewsArtTitle).Data),
1426                 Poster:        string(cc.UserName),
1427                 Date:          toHotlineTime(time.Now()),
1428                 PrevArt:       []byte{0, 0, 0, 0},
1429                 NextArt:       []byte{0, 0, 0, 0},
1430                 ParentArt:     bs,
1431                 FirstChildArt: []byte{0, 0, 0, 0},
1432                 DataFlav:      []byte("text/plain"),
1433                 Data:          string(t.GetField(FieldNewsArtData).Data),
1434         }
1435
1436         var keys []int
1437         for k := range cat.Articles {
1438                 keys = append(keys, int(k))
1439         }
1440
1441         nextID := uint32(1)
1442         if len(keys) > 0 {
1443                 sort.Ints(keys)
1444                 prevID := uint32(keys[len(keys)-1])
1445                 nextID = prevID + 1
1446
1447                 binary.BigEndian.PutUint32(newArt.PrevArt, prevID)
1448
1449                 // Set next article ID
1450                 binary.BigEndian.PutUint32(cat.Articles[prevID].NextArt, nextID)
1451         }
1452
1453         // Update parent article with first child reply
1454         parentID := convertedArtID
1455         if parentID != 0 {
1456                 parentArt := cat.Articles[parentID]
1457
1458                 if bytes.Equal(parentArt.FirstChildArt, []byte{0, 0, 0, 0}) {
1459                         binary.BigEndian.PutUint32(parentArt.FirstChildArt, nextID)
1460                 }
1461         }
1462
1463         cat.Articles[nextID] = &newArt
1464
1465         cats[catName] = cat
1466         if err := cc.Server.writeThreadedNews(); err != nil {
1467                 return res, err
1468         }
1469
1470         res = append(res, cc.NewReply(t))
1471         return res, err
1472 }
1473
1474 // HandleGetMsgs returns the flat news data
1475 func HandleGetMsgs(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1476         if !cc.Authorize(accessNewsReadArt) {
1477                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1478                 return res, err
1479         }
1480
1481         res = append(res, cc.NewReply(t, NewField(FieldData, cc.Server.FlatNews)))
1482
1483         return res, err
1484 }
1485
1486 func HandleDownloadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1487         if !cc.Authorize(accessDownloadFile) {
1488                 res = append(res, cc.NewErrReply(t, "You are not allowed to download files."))
1489                 return res, err
1490         }
1491
1492         fileName := t.GetField(FieldFileName).Data
1493         filePath := t.GetField(FieldFilePath).Data
1494         resumeData := t.GetField(FieldFileResumeData).Data
1495
1496         var dataOffset int64
1497         var frd FileResumeData
1498         if resumeData != nil {
1499                 if err := frd.UnmarshalBinary(t.GetField(FieldFileResumeData).Data); err != nil {
1500                         return res, err
1501                 }
1502                 // TODO: handle rsrc fork offset
1503                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1504         }
1505
1506         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1507         if err != nil {
1508                 return res, err
1509         }
1510
1511         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, dataOffset)
1512         if err != nil {
1513                 return res, err
1514         }
1515
1516         xferSize := hlFile.ffo.TransferSize(0)
1517
1518         ft := cc.newFileTransfer(FileDownload, fileName, filePath, xferSize)
1519
1520         // TODO: refactor to remove this
1521         if resumeData != nil {
1522                 var frd FileResumeData
1523                 if err := frd.UnmarshalBinary(t.GetField(FieldFileResumeData).Data); err != nil {
1524                         return res, err
1525                 }
1526                 ft.fileResumeData = &frd
1527         }
1528
1529         // Optional field for when a HL v1.5+ client requests file preview
1530         // Used only for TEXT, JPEG, GIFF, BMP or PICT files
1531         // The value will always be 2
1532         if t.GetField(FieldFileTransferOptions).Data != nil {
1533                 ft.options = t.GetField(FieldFileTransferOptions).Data
1534                 xferSize = hlFile.ffo.FlatFileDataForkHeader.DataSize[:]
1535         }
1536
1537         res = append(res, cc.NewReply(t,
1538                 NewField(FieldRefNum, ft.refNum[:]),
1539                 NewField(FieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1540                 NewField(FieldTransferSize, xferSize),
1541                 NewField(FieldFileSize, hlFile.ffo.FlatFileDataForkHeader.DataSize[:]),
1542         ))
1543
1544         return res, err
1545 }
1546
1547 // Download all files from the specified folder and sub-folders
1548 func HandleDownloadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1549         if !cc.Authorize(accessDownloadFile) {
1550                 res = append(res, cc.NewErrReply(t, "You are not allowed to download folders."))
1551                 return res, err
1552         }
1553
1554         fullFilePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(FieldFilePath).Data, t.GetField(FieldFileName).Data)
1555         if err != nil {
1556                 return res, err
1557         }
1558
1559         transferSize, err := CalcTotalSize(fullFilePath)
1560         if err != nil {
1561                 return res, err
1562         }
1563         itemCount, err := CalcItemCount(fullFilePath)
1564         if err != nil {
1565                 return res, err
1566         }
1567
1568         fileTransfer := cc.newFileTransfer(FolderDownload, t.GetField(FieldFileName).Data, t.GetField(FieldFilePath).Data, transferSize)
1569
1570         var fp FilePath
1571         _, err = fp.Write(t.GetField(FieldFilePath).Data)
1572         if err != nil {
1573                 return res, err
1574         }
1575
1576         res = append(res, cc.NewReply(t,
1577                 NewField(FieldRefNum, fileTransfer.ReferenceNumber),
1578                 NewField(FieldTransferSize, transferSize),
1579                 NewField(FieldFolderItemCount, itemCount),
1580                 NewField(FieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1581         ))
1582         return res, err
1583 }
1584
1585 // Upload all files from the local folder and its subfolders to the specified path on the server
1586 // Fields used in the request
1587 // 201  File name
1588 // 202  File path
1589 // 108  transfer size   Total size of all items in the folder
1590 // 220  Folder item count
1591 // 204  File transfer options   "Optional Currently set to 1" (TODO: ??)
1592 func HandleUploadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1593         var fp FilePath
1594         if t.GetField(FieldFilePath).Data != nil {
1595                 if _, err = fp.Write(t.GetField(FieldFilePath).Data); err != nil {
1596                         return res, err
1597                 }
1598         }
1599
1600         // Handle special cases for Upload and Drop Box folders
1601         if !cc.Authorize(accessUploadAnywhere) {
1602                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1603                         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))))
1604                         return res, err
1605                 }
1606         }
1607
1608         fileTransfer := cc.newFileTransfer(FolderUpload,
1609                 t.GetField(FieldFileName).Data,
1610                 t.GetField(FieldFilePath).Data,
1611                 t.GetField(FieldTransferSize).Data,
1612         )
1613
1614         fileTransfer.FolderItemCount = t.GetField(FieldFolderItemCount).Data
1615
1616         res = append(res, cc.NewReply(t, NewField(FieldRefNum, fileTransfer.ReferenceNumber)))
1617         return res, err
1618 }
1619
1620 // HandleUploadFile
1621 // Fields used in the request:
1622 // 201  File name
1623 // 202  File path
1624 // 204  File transfer options   "Optional
1625 // Used only to resume download, currently has value 2"
1626 // 108  File transfer size      "Optional used if download is not resumed"
1627 func HandleUploadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1628         if !cc.Authorize(accessUploadFile) {
1629                 res = append(res, cc.NewErrReply(t, "You are not allowed to upload files."))
1630                 return res, err
1631         }
1632
1633         fileName := t.GetField(FieldFileName).Data
1634         filePath := t.GetField(FieldFilePath).Data
1635         transferOptions := t.GetField(FieldFileTransferOptions).Data
1636         transferSize := t.GetField(FieldTransferSize).Data // not sent for resume
1637
1638         var fp FilePath
1639         if filePath != nil {
1640                 if _, err = fp.Write(filePath); err != nil {
1641                         return res, err
1642                 }
1643         }
1644
1645         // Handle special cases for Upload and Drop Box folders
1646         if !cc.Authorize(accessUploadAnywhere) {
1647                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1648                         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))))
1649                         return res, err
1650                 }
1651         }
1652         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1653         if err != nil {
1654                 return res, err
1655         }
1656
1657         if _, err := cc.Server.FS.Stat(fullFilePath); err == nil {
1658                 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))))
1659                 return res, err
1660         }
1661
1662         ft := cc.newFileTransfer(FileUpload, fileName, filePath, transferSize)
1663
1664         replyT := cc.NewReply(t, NewField(FieldRefNum, ft.ReferenceNumber))
1665
1666         // client has requested to resume a partially transferred file
1667         if transferOptions != nil {
1668                 fileInfo, err := cc.Server.FS.Stat(fullFilePath + incompleteFileSuffix)
1669                 if err != nil {
1670                         return res, err
1671                 }
1672
1673                 offset := make([]byte, 4)
1674                 binary.BigEndian.PutUint32(offset, uint32(fileInfo.Size()))
1675
1676                 fileResumeData := NewFileResumeData([]ForkInfoList{
1677                         *NewForkInfoList(offset),
1678                 })
1679
1680                 b, _ := fileResumeData.BinaryMarshal()
1681
1682                 ft.TransferSize = offset
1683
1684                 replyT.Fields = append(replyT.Fields, NewField(FieldFileResumeData, b))
1685         }
1686
1687         res = append(res, replyT)
1688         return res, err
1689 }
1690
1691 func HandleSetClientUserInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1692         if len(t.GetField(FieldUserIconID).Data) == 4 {
1693                 cc.Icon = t.GetField(FieldUserIconID).Data[2:]
1694         } else {
1695                 cc.Icon = t.GetField(FieldUserIconID).Data
1696         }
1697         if cc.Authorize(accessAnyName) {
1698                 cc.UserName = t.GetField(FieldUserName).Data
1699         }
1700
1701         // the options field is only passed by the client versions > 1.2.3.
1702         options := t.GetField(FieldOptions).Data
1703         if options != nil {
1704                 optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1705                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(cc.Flags)))
1706
1707                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePM, optBitmap.Bit(refusePM))
1708                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1709
1710                 flagBitmap.SetBit(flagBitmap, UserFlagRefusePChat, optBitmap.Bit(refuseChat))
1711                 binary.BigEndian.PutUint16(cc.Flags, uint16(flagBitmap.Int64()))
1712
1713                 // Check auto response
1714                 if optBitmap.Bit(autoResponse) == 1 {
1715                         cc.AutoReply = t.GetField(FieldAutomaticResponse).Data
1716                 } else {
1717                         cc.AutoReply = []byte{}
1718                 }
1719         }
1720
1721         for _, c := range sortedClients(cc.Server.Clients) {
1722                 res = append(res, *NewTransaction(
1723                         TranNotifyChangeUser,
1724                         c.ID,
1725                         NewField(FieldUserID, *cc.ID),
1726                         NewField(FieldUserIconID, cc.Icon),
1727                         NewField(FieldUserFlags, cc.Flags),
1728                         NewField(FieldUserName, cc.UserName),
1729                 ))
1730         }
1731
1732         return res, err
1733 }
1734
1735 // HandleKeepAlive responds to keepalive transactions with an empty reply
1736 // * HL 1.9.2 Client sends keepalive msg every 3 minutes
1737 // * HL 1.2.3 Client doesn't send keepalives
1738 func HandleKeepAlive(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1739         res = append(res, cc.NewReply(t))
1740
1741         return res, err
1742 }
1743
1744 func HandleGetFileNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1745         fullPath, err := readPath(
1746                 cc.Server.Config.FileRoot,
1747                 t.GetField(FieldFilePath).Data,
1748                 nil,
1749         )
1750         if err != nil {
1751                 return res, err
1752         }
1753
1754         var fp FilePath
1755         if t.GetField(FieldFilePath).Data != nil {
1756                 if _, err = fp.Write(t.GetField(FieldFilePath).Data); err != nil {
1757                         return res, err
1758                 }
1759         }
1760
1761         // Handle special case for drop box folders
1762         if fp.IsDropbox() && !cc.Authorize(accessViewDropBoxes) {
1763                 res = append(res, cc.NewErrReply(t, "You are not allowed to view drop boxes."))
1764                 return res, err
1765         }
1766
1767         fileNames, err := getFileNameList(fullPath, cc.Server.Config.IgnoreFiles)
1768         if err != nil {
1769                 return res, err
1770         }
1771
1772         res = append(res, cc.NewReply(t, fileNames...))
1773
1774         return res, err
1775 }
1776
1777 // =================================
1778 //     Hotline private chat flow
1779 // =================================
1780 // 1. ClientA sends TranInviteNewChat to server with user ID to invite
1781 // 2. Server creates new ChatID
1782 // 3. Server sends TranInviteToChat to invitee
1783 // 4. Server replies to ClientA with new Chat ID
1784 //
1785 // A dialog box pops up in the invitee client with options to accept or decline the invitation.
1786 // If Accepted is clicked:
1787 // 1. ClientB sends TranJoinChat with FieldChatID
1788
1789 // HandleInviteNewChat invites users to new private chat
1790 func HandleInviteNewChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1791         if !cc.Authorize(accessOpenChat) {
1792                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1793                 return res, err
1794         }
1795
1796         // Client to Invite
1797         targetID := t.GetField(FieldUserID).Data
1798         newChatID := cc.Server.NewPrivateChat(cc)
1799
1800         // Check if target user has "Refuse private chat" flag
1801         binary.BigEndian.Uint16(targetID)
1802         targetClient := cc.Server.Clients[binary.BigEndian.Uint16(targetID)]
1803
1804         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(targetClient.Flags)))
1805         if flagBitmap.Bit(UserFlagRefusePChat) == 1 {
1806                 res = append(res,
1807                         *NewTransaction(
1808                                 TranServerMsg,
1809                                 cc.ID,
1810                                 NewField(FieldData, []byte(string(targetClient.UserName)+" does not accept private chats.")),
1811                                 NewField(FieldUserName, targetClient.UserName),
1812                                 NewField(FieldUserID, *targetClient.ID),
1813                                 NewField(FieldOptions, []byte{0, 2}),
1814                         ),
1815                 )
1816         } else {
1817                 res = append(res,
1818                         *NewTransaction(
1819                                 TranInviteToChat,
1820                                 &targetID,
1821                                 NewField(FieldChatID, newChatID),
1822                                 NewField(FieldUserName, cc.UserName),
1823                                 NewField(FieldUserID, *cc.ID),
1824                         ),
1825                 )
1826         }
1827
1828         res = append(res,
1829                 cc.NewReply(t,
1830                         NewField(FieldChatID, newChatID),
1831                         NewField(FieldUserName, cc.UserName),
1832                         NewField(FieldUserID, *cc.ID),
1833                         NewField(FieldUserIconID, cc.Icon),
1834                         NewField(FieldUserFlags, cc.Flags),
1835                 ),
1836         )
1837
1838         return res, err
1839 }
1840
1841 func HandleInviteToChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1842         if !cc.Authorize(accessOpenChat) {
1843                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1844                 return res, err
1845         }
1846
1847         // Client to Invite
1848         targetID := t.GetField(FieldUserID).Data
1849         chatID := t.GetField(FieldChatID).Data
1850
1851         res = append(res,
1852                 *NewTransaction(
1853                         TranInviteToChat,
1854                         &targetID,
1855                         NewField(FieldChatID, chatID),
1856                         NewField(FieldUserName, cc.UserName),
1857                         NewField(FieldUserID, *cc.ID),
1858                 ),
1859         )
1860         res = append(res,
1861                 cc.NewReply(
1862                         t,
1863                         NewField(FieldChatID, chatID),
1864                         NewField(FieldUserName, cc.UserName),
1865                         NewField(FieldUserID, *cc.ID),
1866                         NewField(FieldUserIconID, cc.Icon),
1867                         NewField(FieldUserFlags, cc.Flags),
1868                 ),
1869         )
1870
1871         return res, err
1872 }
1873
1874 func HandleRejectChatInvite(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1875         chatID := t.GetField(FieldChatID).Data
1876         chatInt := binary.BigEndian.Uint32(chatID)
1877
1878         privChat := cc.Server.PrivateChats[chatInt]
1879
1880         resMsg := append(cc.UserName, []byte(" declined invitation to chat")...)
1881
1882         for _, c := range sortedClients(privChat.ClientConn) {
1883                 res = append(res,
1884                         *NewTransaction(
1885                                 TranChatMsg,
1886                                 c.ID,
1887                                 NewField(FieldChatID, chatID),
1888                                 NewField(FieldData, resMsg),
1889                         ),
1890                 )
1891         }
1892
1893         return res, err
1894 }
1895
1896 // HandleJoinChat is sent from a v1.8+ Hotline client when the joins a private chat
1897 // Fields used in the reply:
1898 // * 115        Chat subject
1899 // * 300        User name with info (Optional)
1900 // * 300        (more user names with info)
1901 func HandleJoinChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1902         chatID := t.GetField(FieldChatID).Data
1903         chatInt := binary.BigEndian.Uint32(chatID)
1904
1905         privChat := cc.Server.PrivateChats[chatInt]
1906
1907         // Send TranNotifyChatChangeUser to current members of the chat to inform of new user
1908         for _, c := range sortedClients(privChat.ClientConn) {
1909                 res = append(res,
1910                         *NewTransaction(
1911                                 TranNotifyChatChangeUser,
1912                                 c.ID,
1913                                 NewField(FieldChatID, chatID),
1914                                 NewField(FieldUserName, cc.UserName),
1915                                 NewField(FieldUserID, *cc.ID),
1916                                 NewField(FieldUserIconID, cc.Icon),
1917                                 NewField(FieldUserFlags, cc.Flags),
1918                         ),
1919                 )
1920         }
1921
1922         privChat.ClientConn[cc.uint16ID()] = cc
1923
1924         replyFields := []Field{NewField(FieldChatSubject, []byte(privChat.Subject))}
1925         for _, c := range sortedClients(privChat.ClientConn) {
1926
1927                 b, err := io.ReadAll(&User{
1928                         ID:    *c.ID,
1929                         Icon:  c.Icon,
1930                         Flags: c.Flags,
1931                         Name:  string(c.UserName),
1932                 })
1933                 if err != nil {
1934                         return res, nil
1935                 }
1936                 replyFields = append(replyFields, NewField(FieldUsernameWithInfo, b))
1937         }
1938
1939         res = append(res, cc.NewReply(t, replyFields...))
1940         return res, err
1941 }
1942
1943 // HandleLeaveChat is sent from a v1.8+ Hotline client when the user exits a private chat
1944 // Fields used in the request:
1945 //   - 114      FieldChatID
1946 //
1947 // Reply is not expected.
1948 func HandleLeaveChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1949         chatID := t.GetField(FieldChatID).Data
1950         chatInt := binary.BigEndian.Uint32(chatID)
1951
1952         privChat, ok := cc.Server.PrivateChats[chatInt]
1953         if !ok {
1954                 return res, nil
1955         }
1956
1957         delete(privChat.ClientConn, cc.uint16ID())
1958
1959         // Notify members of the private chat that the user has left
1960         for _, c := range sortedClients(privChat.ClientConn) {
1961                 res = append(res,
1962                         *NewTransaction(
1963                                 TranNotifyChatDeleteUser,
1964                                 c.ID,
1965                                 NewField(FieldChatID, chatID),
1966                                 NewField(FieldUserID, *cc.ID),
1967                         ),
1968                 )
1969         }
1970
1971         return res, err
1972 }
1973
1974 // HandleSetChatSubject is sent from a v1.8+ Hotline client when the user sets a private chat subject
1975 // Fields used in the request:
1976 // * 114        Chat ID
1977 // * 115        Chat subject
1978 // Reply is not expected.
1979 func HandleSetChatSubject(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1980         chatID := t.GetField(FieldChatID).Data
1981         chatInt := binary.BigEndian.Uint32(chatID)
1982
1983         privChat := cc.Server.PrivateChats[chatInt]
1984         privChat.Subject = string(t.GetField(FieldChatSubject).Data)
1985
1986         for _, c := range sortedClients(privChat.ClientConn) {
1987                 res = append(res,
1988                         *NewTransaction(
1989                                 TranNotifyChatSubject,
1990                                 c.ID,
1991                                 NewField(FieldChatID, chatID),
1992                                 NewField(FieldChatSubject, t.GetField(FieldChatSubject).Data),
1993                         ),
1994                 )
1995         }
1996
1997         return res, err
1998 }
1999
2000 // HandleMakeAlias makes a file alias using the specified path.
2001 // Fields used in the request:
2002 // 201  File name
2003 // 202  File path
2004 // 212  File new path   Destination path
2005 //
2006 // Fields used in the reply:
2007 // None
2008 func HandleMakeAlias(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
2009         if !cc.Authorize(accessMakeAlias) {
2010                 res = append(res, cc.NewErrReply(t, "You are not allowed to make aliases."))
2011                 return res, err
2012         }
2013         fileName := t.GetField(FieldFileName).Data
2014         filePath := t.GetField(FieldFilePath).Data
2015         fileNewPath := t.GetField(FieldFileNewPath).Data
2016
2017         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
2018         if err != nil {
2019                 return res, err
2020         }
2021
2022         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, fileNewPath, fileName)
2023         if err != nil {
2024                 return res, err
2025         }
2026
2027         cc.logger.Debugw("Make alias", "src", fullFilePath, "dst", fullNewFilePath)
2028
2029         if err := cc.Server.FS.Symlink(fullFilePath, fullNewFilePath); err != nil {
2030                 res = append(res, cc.NewErrReply(t, "Error creating alias"))
2031                 return res, nil
2032         }
2033
2034         res = append(res, cc.NewReply(t))
2035         return res, err
2036 }
2037
2038 // HandleDownloadBanner handles requests for a new banner from the server
2039 // Fields used in the request:
2040 // None
2041 // Fields used in the reply:
2042 // 107  FieldRefNum                     Used later for transfer
2043 // 108  FieldTransferSize       Size of data to be downloaded
2044 func HandleDownloadBanner(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
2045         fi, err := cc.Server.FS.Stat(filepath.Join(cc.Server.ConfigDir, cc.Server.Config.BannerFile))
2046         if err != nil {
2047                 return res, err
2048         }
2049
2050         ft := cc.newFileTransfer(bannerDownload, []byte{}, []byte{}, make([]byte, 4))
2051
2052         binary.BigEndian.PutUint32(ft.TransferSize, uint32(fi.Size()))
2053
2054         res = append(res, cc.NewReply(t,
2055                 NewField(FieldRefNum, ft.refNum[:]),
2056                 NewField(FieldTransferSize, ft.TransferSize),
2057         ))
2058
2059         return res, err
2060 }