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Merge pull request #351 from Embarcadero/scanlibs
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Scanning loaded libraries looking for Python symbols
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@pyscripter
pyscripter authored Feb 22, 2022
2 parents d271451 + 8252793 commit 2c84d57
Showing 1 changed file with 163 additions and 13 deletions.
176 changes: 163 additions & 13 deletions Source/PythonEngine.pas
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Original file line number Diff line number Diff line change
Expand Up @@ -1197,8 +1197,13 @@ TDynamicDll = class(TComponent)
procedure DoOpenDll(const aDllName : string); virtual;
function GetDllPath : string;

procedure LoadPythonInfoFromModule;
function GetPythonModuleFromProcess(): NativeUInt;
function HasHostSymbols(): boolean;
procedure LoadFromHostSymbols();
//Loading strategies
function TryLoadFromHostSymbols(): boolean;
function TryLoadFromCurrentProcess(): boolean;
public
// Constructors & Destructors
constructor Create(AOwner: TComponent); override;
Expand Down Expand Up @@ -2783,6 +2788,7 @@ implementation
{$ENDIF}
{$IFDEF MSWINDOWS}
Registry,
PsAPI,
{$ENDIF}
Math;

Expand Down Expand Up @@ -3019,6 +3025,123 @@ function TDynamicDll.GetDllPath : string;
end;
end;

function TDynamicDll.GetPythonModuleFromProcess(): NativeUInt;

{$IFNDEF FPC}

function HasSymbols(const AModule: NativeUInt): boolean;
var
LPy_GetBuildInfo: function : PAnsiChar; cdecl;
LPy_IsInitialized: function: integer; cdecl;
begin
FDLLHandle := AModule;
try
LPy_GetBuildInfo := Import('Py_GetBuildInfo', false);
LPy_IsInitialized := Import('Py_IsInitialized', false);
Result := Assigned(LPy_GetBuildInfo) and Assigned(LPy_GetBuildInfo())
and Assigned(LPy_IsInitialized) and (LPy_IsInitialized() <> 0);
finally
FDLLHandle := 0;
end;
end;

{$IFDEF LINUX}
function GetPythonModule: NativeUInt;
type
plink_map = ^link_map;
link_map = record
l_addr: Pointer;
l_name: PAnsiChar;
l_ld: Pointer;
l_next, l_prev: plink_map;
end;
var
LPseudoHandle: NativeUInt;
LPLinkMap: plink_map;
LModuleName: string;
LModuleHandle: NativeUInt;
begin
//In Linux pseudo handle is in fact a pointer to the the corresponding link_map structure
//The dlopen(nil, RTLD_NOW) result is the pseudo handle for the main executable (similar to GetModuleHandle(nil) in Windows).
LPseudoHandle := dlopen(nil, RTLD_NOW);
//Points to the first link_map
LPLinkMap := plink_map(LPseudoHandle).l_next.l_next;
while Assigned(LPLinkMap) do begin
LModuleName := String(LPLinkMap.l_name);
LModuleHandle := LoadLibrary(PChar(LModuleName));
if HasSymbols(LModuleHandle) then
Exit(LModuleHandle);
LPLinkMap := LPLinkMap.l_next;
end;
Result := 0;
end;
{$ENDIF LINUX}

{$IFDEF OSX}
function GetPythonModule: NativeUInt;
var
LIndex: integer;
LName: PAnsiChar;
LModuleName: string;
LModuleHandle: NativeUInt;
begin
LIndex := 0;
LName := _dyld_get_image_name(LIndex);
while (LName <> nil) do begin
LModuleName := String(LName);
LModuleHandle := LoadLibrary(PChar(LModuleName));
if HasSymbols(LModuleHandle) then
Exit(LModuleHandle);
Inc(LIndex);
LName := _dyld_get_image_name(LIndex);
end;
Result := 0;
end;
{$ENDIF OSX}

{$IFDEF MSWINDOWS}
function GetPythonModule: NativeUInt;
var
LHProcess: NativeUInt;
LHModules: array of NativeUInt;
LCbNeeded: Cardinal;
I: Integer;
LModName: array[0..1024] of char;
begin
SetLength(LHModules, 1024);
LHProcess := OpenProcess(PROCESS_QUERY_INFORMATION + PROCESS_VM_READ, false, GetCurrentProcessId());
if LHProcess > 0 then begin
try
if EnumProcessModules(LHProcess, @LHModules[0], 1024 * SizeOf(HMODULE), LCbNeeded) then begin
SetLength(LHModules, LCbNeeded div SizeOf(THandle));
for I := 0 to Length(LHModules) -1 do begin
GetModuleBaseName(LHProcess, LHModules[I], LModName, SizeOf(LModName));
if HasSymbols(LHModules[I]) then begin
Exit(LHModules[I]);
end;
end;
end;
finally
CloseHandle(LHProcess);
end;
end;
Result := 0;
end;
{$ENDIF MSWINDOWS}
{$ENDIF FPC}

begin
{$IF DEFINED(LINUX) OR DEFINED(OSX) OR DEFINED(MSWINDOWS)}
{$IFNDEF FPC}
Result := GetPythonModule();
{$ELSE}
Result := 0;
{$ENDIF}
{$ELSE}
Result := 0;
{$IFEND}
end;

procedure TDynamicDll.OpenDll(const aDllName : string);
var
s : string;
Expand Down Expand Up @@ -3107,15 +3230,42 @@ function TDynamicDll.IsHandleValid : Boolean;
{$ENDIF}
end;

function TDynamicDll.TryLoadFromCurrentProcess: boolean;
begin
FDLLHandle := GetPythonModuleFromProcess();
if not IsHandleValid() then
Exit(false);

BeforeLoad();
LoadPythonInfoFromModule();
AfterLoad();
Result := true;
end;

function TDynamicDll.TryLoadFromHostSymbols: boolean;
begin
//We want to look in for host symbols at first
FDLLHandle := 0;
Result := HasHostSymbols();
if Result then
LoadFromHostSymbols();
end;

procedure TDynamicDll.LoadFromHostSymbols;
begin
BeforeLoad();
LoadPythonInfoFromModule();
AfterLoad();
end;

procedure TDynamicDll.LoadPythonInfoFromModule;
var
LPy_GetVersion: function: PAnsiChar; cdecl;
LPy_GetProgramFullPath: function: PAnsiChar; cdecl;
LVersion: string;
LInfo: TPythonVersionProp;
LFound: boolean;
begin
BeforeLoad();
//According to the doc:
//Return the full program name of the Python executable.
//The value is available to Python code as sys.executable.
Expand Down Expand Up @@ -3143,9 +3293,7 @@ procedure TDynamicDll.LoadFromHostSymbols;
end;

if not LFound then
raise EDLLLoadError.Create('Undetermined Python version from host symbols.');

AfterLoad();
raise EDLLLoadError.Create('Undetermined Python version from loaded module.');
end;

procedure TDynamicDll.LoadDll;
Expand All @@ -3155,14 +3303,18 @@ procedure TDynamicDll.LoadDll;

procedure TDynamicDll.LoadDllInExtensionModule;
begin
//We want to look in for host symbols at first
FDLLHandle := 0;
if not ModuleIsLib then
Exit;

FInExtensionModule := True;
if HasHostSymbols() then
LoadFromHostSymbols()
else
LoadDLL;

if TryLoadFromHostSymbols() then
Exit;

if TryLoadFromCurrentProcess() then
Exit;

LoadDLL();
end;

procedure TDynamicDll.UnloadDll;
Expand Down Expand Up @@ -3201,9 +3353,6 @@ function TDynamicDll.HasHostSymbols: boolean;
var
LPy_IsInitialized: function: integer; cdecl;
begin
if not ModuleIsLib then
Exit(false);

LPy_IsInitialized := Import('Py_IsInitialized', false);
Result := Assigned(LPy_IsInitialized) and (LPy_IsInitialized() <> 0);
end;
Expand Down Expand Up @@ -9241,6 +9390,7 @@ function IsPythonVersionRegistered(PythonVersion : string;
except
end;
end;

{$ENDIF}

procedure PythonVersionFromDLLName(LibName: string; out MajorVersion, MinorVersion: integer);
Expand Down

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