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Merged
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Mar 25, 2021
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Try libdl.so.2 on Linux before libdl.so #1425

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try libdl.so.2 on Linux before libdl.so 
also refactored LibraryLoader to share code between Linux and Mac

fixes #1422
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@lostmsu
lostmsu committed Mar 25, 2021
commit 483f1922fda4b477b6dfa549b65e068183c7700c
109 changes: 109 additions & 0 deletions src/runtime/platform/LibDL.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,109 @@
#pragma warning disable IDE1006 // Naming Styles (interface for native functions)
using System;
using System.Runtime.InteropServices;

namespace Python.Runtime.Platform
{
interface ILibDL
{
IntPtr dlopen(string fileName, int flags);
IntPtr dlsym(IntPtr handle, string symbol);
int dlclose(IntPtr handle);
IntPtr dlerror();

int RTLD_NOW { get; }
int RTLD_GLOBAL { get; }
IntPtr RTLD_DEFAULT { get; }
}

class LinuxLibDL : ILibDL
{
private const string NativeDll = "libdl.so";

public int RTLD_NOW => 0x2;
public int RTLD_GLOBAL => 0x100;
public IntPtr RTLD_DEFAULT => IntPtr.Zero;

public static ILibDL GetInstance()
{
try
{
ILibDL libdl2 = new LinuxLibDL2();
// call dlerror to ensure library is resolved
libdl2.dlerror();
return libdl2;
} catch (DllNotFoundException)
{
return new LinuxLibDL();
}
}

IntPtr ILibDL.dlopen(string fileName, int flags) => dlopen(fileName, flags);
IntPtr ILibDL.dlsym(IntPtr handle, string symbol) => dlsym(handle, symbol);
int ILibDL.dlclose(IntPtr handle) => dlclose(handle);
IntPtr ILibDL.dlerror() => dlerror();

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlopen(string fileName, int flags);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlsym(IntPtr handle, string symbol);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern int dlclose(IntPtr handle);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr dlerror();
}

class LinuxLibDL2 : ILibDL
{
private const string NativeDll = "libdl.so.2";

public int RTLD_NOW => 0x2;
public int RTLD_GLOBAL => 0x100;
public IntPtr RTLD_DEFAULT => IntPtr.Zero;

IntPtr ILibDL.dlopen(string fileName, int flags) => dlopen(fileName, flags);
IntPtr ILibDL.dlsym(IntPtr handle, string symbol) => dlsym(handle, symbol);
int ILibDL.dlclose(IntPtr handle) => dlclose(handle);
IntPtr ILibDL.dlerror() => dlerror();

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlopen(string fileName, int flags);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlsym(IntPtr handle, string symbol);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern int dlclose(IntPtr handle);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr dlerror();
}

class MacLibDL : ILibDL
{
public int RTLD_NOW => 0x2;
public int RTLD_GLOBAL => 0x8;
const string NativeDll = "/usr/lib/libSystem.dylib";
public IntPtr RTLD_DEFAULT => new(-2);

IntPtr ILibDL.dlopen(string fileName, int flags) => dlopen(fileName, flags);
IntPtr ILibDL.dlsym(IntPtr handle, string symbol) => dlsym(handle, symbol);
int ILibDL.dlclose(IntPtr handle) => dlclose(handle);
IntPtr ILibDL.dlerror() => dlerror();

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlopen(string fileName, int flags);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlsym(IntPtr handle, string symbol);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern int dlclose(IntPtr handle);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr dlerror();
}
}
104 changes: 12 additions & 92 deletions src/runtime/platform/LibraryLoader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,9 +28,9 @@ public static ILibraryLoader Instance
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
_instance = new WindowsLoader();
else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
_instance = new LinuxLoader();
_instance = new PosixLoader(LinuxLibDL.GetInstance());
else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
_instance = new DarwinLoader();
_instance = new PosixLoader(new MacLibDL());
else
throw new PlatformNotSupportedException(
"This operating system is not supported"
Expand All @@ -42,87 +42,19 @@ public static ILibraryLoader Instance
}
}

class LinuxLoader : ILibraryLoader
class PosixLoader : ILibraryLoader
{
private static int RTLD_NOW = 0x2;
private static int RTLD_GLOBAL = 0x100;
private static IntPtr RTLD_DEFAULT = IntPtr.Zero;
private const string NativeDll = "libdl.so";
private readonly ILibDL libDL;

public IntPtr Load(string dllToLoad)
{
ClearError();
var res = dlopen(dllToLoad, RTLD_NOW | RTLD_GLOBAL);
if (res == IntPtr.Zero)
{
var err = GetError();
throw new DllNotFoundException($"Could not load {dllToLoad} with flags RTLD_NOW | RTLD_GLOBAL: {err}");
}

return res;
}

public void Free(IntPtr handle)
{
dlclose(handle);
}

public IntPtr GetFunction(IntPtr dllHandle, string name)
{
// look in the exe if dllHandle is NULL
if (dllHandle == IntPtr.Zero)
{
dllHandle = RTLD_DEFAULT;
}

ClearError();
IntPtr res = dlsym(dllHandle, name);
if (res == IntPtr.Zero)
{
var err = GetError();
throw new MissingMethodException($"Failed to load symbol {name}: {err}");
}
return res;
}

void ClearError()
public PosixLoader(ILibDL libDL)
{
dlerror();
}

string GetError()
{
var res = dlerror();
if (res != IntPtr.Zero)
return Marshal.PtrToStringAnsi(res);
else
return null;
this.libDL = libDL ?? throw new ArgumentNullException(nameof(libDL));
}

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
public static extern IntPtr dlopen(string fileName, int flags);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlsym(IntPtr handle, string symbol);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern int dlclose(IntPtr handle);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr dlerror();
}

class DarwinLoader : ILibraryLoader
{
private static int RTLD_NOW = 0x2;
private static int RTLD_GLOBAL = 0x8;
private const string NativeDll = "/usr/lib/libSystem.dylib";
private static IntPtr RTLD_DEFAULT = new IntPtr(-2);

public IntPtr Load(string dllToLoad)
{
ClearError();
var res = dlopen(dllToLoad, RTLD_NOW | RTLD_GLOBAL);
var res = libDL.dlopen(dllToLoad, libDL.RTLD_NOW | libDL.RTLD_GLOBAL);
if (res == IntPtr.Zero)
{
var err = GetError();
Expand All @@ -134,19 +66,19 @@ public IntPtr Load(string dllToLoad)

public void Free(IntPtr handle)
{
dlclose(handle);
libDL.dlclose(handle);
}

public IntPtr GetFunction(IntPtr dllHandle, string name)
{
// look in the exe if dllHandle is NULL
if (dllHandle == IntPtr.Zero)
{
dllHandle = RTLD_DEFAULT;
dllHandle = libDL.RTLD_DEFAULT;
}

ClearError();
IntPtr res = dlsym(dllHandle, name);
IntPtr res = libDL.dlsym(dllHandle, name);
if (res == IntPtr.Zero)
{
var err = GetError();
Expand All @@ -157,29 +89,17 @@ public IntPtr GetFunction(IntPtr dllHandle, string name)

void ClearError()
{
dlerror();
libDL.dlerror();
}

string GetError()
{
var res = dlerror();
var res = libDL.dlerror();
if (res != IntPtr.Zero)
return Marshal.PtrToStringAnsi(res);
else
return null;
}

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
public static extern IntPtr dlopen(String fileName, int flags);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr dlsym(IntPtr handle, String symbol);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern int dlclose(IntPtr handle);

[DllImport(NativeDll, CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr dlerror();
}

class WindowsLoader : ILibraryLoader
Expand Down