diff options
Diffstat (limited to 'vfs/ModuleLoader.pas')
| -rw-r--r-- | vfs/ModuleLoader.pas | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/vfs/ModuleLoader.pas b/vfs/ModuleLoader.pas new file mode 100644 index 0000000..51351dd --- /dev/null +++ b/vfs/ModuleLoader.pas @@ -0,0 +1,156 @@ +{******************************************************************} +{ } +{ Project JEDI } +{ OS independent Dynamic Loading Helpers } +{ } +{ The initial developer of the this code is } +{ Robert Marquardt <robert_marquardt@gmx.de) } +{ } +{ Copyright (C) 2000, 2001 Robert Marquardt. } +{ } +{ Obtained through: } +{ Joint Endeavour of Delphi Innovators (Project JEDI) } +{ } +{ You may retrieve the latest version of this file at the Project } +{ JEDI home page, located at http://delphi-jedi.org } +{ } +{ The contents of this file are used with permission, subject to } +{ the Mozilla Public License Version 1.1 (the "License"); you may } +{ not use this file except in compliance with the License. You may } +{ obtain a copy of the License at } +{ http://www.mozilla.org/NPL/NPL-1_1Final.html } +{ } +{ Software distributed under the License is distributed on an } +{ "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or } +{ implied. See the License for the specific language governing } +{ rights and limitations under the License. } +{ } +{******************************************************************} + +unit ModuleLoader; + +interface +{$WEAKPACKAGEUNIT ON} + + +uses + Libc; +type + // Handle to a loaded .so + TModuleHandle = Pointer; + +const + // Value designating an unassigned TModuleHandle od a failed loading + INVALID_MODULEHANDLE_VALUE = TModuleHandle(nil); + +function LoadModule(var Module: TModuleHandle; FileName: string): Boolean; +function LoadModuleEx(var Module: TModuleHandle; FileName: string; Flags: Cardinal): Boolean; +procedure UnloadModule(var Module: TModuleHandle); +function GetModuleSymbol(Module: TModuleHandle; SymbolName: string): Pointer; +function GetModuleSymbolEx(Module: TModuleHandle; SymbolName: string; var Accu: Boolean): Pointer; +function ReadModuleData(Module: TModuleHandle; SymbolName: string; var Buffer; Size: Cardinal): Boolean; +function WriteModuleData(Module: TModuleHandle; SymbolName: string; var Buffer; Size: Cardinal): Boolean; + +implementation + +// load the .so file FileName +// the rules for FileName are those of dlopen() +// Returns: True = success, False = failure to load +// Assigns: the handle of the loaded .so to Module +// Warning: if Module has any other value than INVALID_MODULEHANDLE_VALUE +// on entry the function will do nothing but returning success. + +function LoadModule(var Module: TModuleHandle; FileName: string): Boolean; +begin + Module := dlopen(PChar(FileName), RTLD_LAZY); + Result := Module <> INVALID_MODULEHANDLE_VALUE; +end; + +// load the .so file FileName +// dlopen() with flags is used to get better control of the loading +// for the allowed values for flags see "man dlopen". + +function LoadModuleEx(var Module: TModuleHandle; FileName: string; Flags: Cardinal): Boolean; +begin + Module := dlopen(PChar(FileName), Flags); + Result := Module <> INVALID_MODULEHANDLE_VALUE; +end; + +// unload a .so loaded with LoadModule or LoadModuleEx +// The procedure will not try to unload a handle with +// value INVALID_MODULEHANDLE_VALUE and assigns this value +// to Module after unload. + +procedure UnloadModule(var Module: TModuleHandle); +begin + if Module <> INVALID_MODULEHANDLE_VALUE then + dlclose(Module); + Module := INVALID_MODULEHANDLE_VALUE; +end; + +// returns the pointer to the symbol named SymbolName +// if it is exported from the .so Module +// nil is returned if the symbol is not available + +function GetModuleSymbol(Module: TModuleHandle; SymbolName: string): Pointer; +begin + Result := nil; + if Module <> INVALID_MODULEHANDLE_VALUE then + Result := dlsym(Module, PChar(SymbolName)); +end; + +// returns the pointer to the symbol named SymbolName +// if it is exported from the .so Module +// nil is returned if the symbol is not available. +// as an extra the boolean variable Accu is updated +// by anding in the success of the function. +// This is very handy for rendering a global result +// when accessing a long list of symbols. + +function GetModuleSymbolEx(Module: TModuleHandle; SymbolName: string; var Accu: Boolean): Pointer; +begin + Result := nil; + if Module <> INVALID_MODULEHANDLE_VALUE then + Result := dlsym(Module, PChar(SymbolName)); + Accu := Accu and (Result <> nil); +end; + +// get the value of variables exported from a .so Module +// Delphi cannot access variables in a .so directly, so +// this function allows to copy the data from the .so. +// Beware! You are accessing the .so memory image directly. +// Be sure to access a variable not a function and be sure +// to read the correct amount of data. + +function ReadModuleData(Module: TModuleHandle; SymbolName: string; var Buffer; Size: Cardinal): Boolean; +var + Sym: Pointer; +begin + Result := True; + Sym := GetModuleSymbolEx(Module, SymbolName, Result); + if Result then + Move(Sym^, Buffer, Size); +end; + +// set the value of variables exported from a .so Module +// Delphi cannot access variables in a .so directly, so +// this function allows to copy the data to the .so! +// BEWARE! You are accessing the .so memory image directly. +// Be sure to access a variable not a function and be sure +// to write the correct amount of data. +// The changes are not persistent. They get lost when the +// .so is unloaded. + +function WriteModuleData(Module: TModuleHandle; SymbolName: string; var Buffer; Size: Cardinal): Boolean; +var + Sym: Pointer; +begin + Result := True; + Sym := GetModuleSymbolEx(Module, SymbolName, Result); + if Result then + Move(Buffer, Sym^, Size); +end; +end. + + + |