[llvm-dev] Compiling and Linking in Sandboxed app using LLVM binary

Denis Antrushin via llvm-dev llvm-dev at lists.llvm.org
Wed Mar 18 07:45:30 PDT 2020


On 18.03.2020 17:34, Edmund Furse via llvm-dev wrote:
> I am trying to build a sandboxed MacOSX app that can compile and link Objective C files.
> 
> I can succeed in doing this if sandboxing is turned off.
> However, when sandboxing is turned on, the compiling works but linking fails with the error:
> clang-9 xcrun: error: cannot be used within an App Sandbox.
> 
> I have downloaded the LLVM binary and created a Tools folder that contains the folders of the binary, namely bin, include, li, libexec, share.
> 
> My example app uses NSTask to call clang from Tools/bin/clang.
> If you call clang from usr/bin/clang then sandboxing will not allow compilation.
> 
> I do not understand why compiling works but linking fails.

Because it tries to pull something from

-syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk

?

> Is it possible to make the linking work within a sandboxed application?
> 
> My code follows.
> 
> Error Message:
> *2020-03-18 12:31:46.517403+0000 NewClangM21[799:13738] Compilation was successfull.*
> *2020-03-18 12:31:46.585428+0000 NewClangM21[799:13738] There was a linking error: clang version 9.0.0 (git://github.com/llvm/llvm-project.git 0399d5a9682b3cef71c653373e38890c63c4c365)*
> *Target: x86_64-apple-darwin18.7.0*
> *Thread model: posix*
> *InstalledDir: /Users/edmundfurse/Documents/NewClang/NewClangM21/DerivedData/NewClangM21/Build/Products/Debug/NewClangM21.app/Contents/Resources/Tools/bin*
> * "/Applications/Xcode.app/Contents/Developer/usr/bin/ld" -demangle -lto_library /Users/edmundfurse/Documents/NewClang/NewClangM21/DerivedData/NewClangM21/Build/Products/Debug/NewClangM21.app/Contents/Resources/Tools/lib/libLTO.dylib -dynamic -arch x86_64 -bundle -macosx_version_min 10.14.0 -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -o "/Users/edmundfurse/Library/Containers/com.uk.imitation.NewClangM21/Data/Library/Application Support/NewClangM21/ImitateScriptSystem/TemporaryFiles/TestMainTestMain" "/Users/edmundfurse/Library/Containers/com.uk.imitation.NewClangM21/Data/Library/Application Support/NewClangM21/ImitateScriptSystem/TemporaryFiles//TestMain.o" -framework Cocoa -framework Foundation -lSystem /Users/edmundfurse/Documents/NewClang/NewClangM21/DerivedData/NewClangM21/Build/Products/Debug/NewClangM21.app/Contents/Resources/Tools/lib/clang/9.0.0/lib/darwin/libclang_rt.osx.a 
> "-F/Users/edmundfurse/Library/Containers/com.uk.imitation.NewClangM21/Data/Library/Application Support/NewClangM21/ImitateScriptSystem/TemporaryFiles/"*
> *xcrun: error: cannot be used within an App Sandbox.*
> *clang-9: error: linker command failed with exit code 1 (use -v to see invocation)*
> *2020-03-18 12:31:46.586103+0000 NewClangM21[799:13738] CASE 1 LINK ERROR*
> **
> 
> ////
> ///  AppDelegate.m/
> ///  NewClangM21/
> ////
> ///  Created by Edmund Furse on 06/03/2020./
> ///  Copyright © 2020 Imitation Ltd. All rights reserved./
> ////
> 
> #import "AppDelegate.h"
> #import "NSFileManager+DirectoryLocations.h"
> 
> *@interface*AppDelegate()
> 
> *@property*(*weak*) *IBOutlet*NSWindow*window;
> *@end*
> 
> *@implementation*AppDelegate
> 
> - (*void*)applicationDidFinishLaunching:(NSNotification *)aNotification {
> /// Insert code here to initialize your application/
> NSString* compileResult = [*self* compileScriptFile:@"TestMain"];
> *if* ([compileResult isEqualToString:@""])
>      {
> NSLog(@"Compilation was successfull.");
>      }
> *BOOL* linkResult = [*self* linkScriptFiles:@"TestMain"];
> *if* (linkResult)
>      {
> NSLog(@"Linking was successfull.");
>      }
> }
> 
> 
> - (*void*)applicationWillTerminate:(NSNotification *)aNotification {
> /// Insert code here to tear down your application/
> }
> 
> - (NSString*)compileScriptFile:(NSString*)theScriptName
> {
> NSString *applicationSupportDirectoryPath = [[NSFileManager defaultManager] applicationSupportDirectory];
> NSString* temporaryFilesDirectoryName = concatenate(applicationSupportDirectoryPath, @"/ImitateScriptSystem/TemporaryFiles/");
> NSString* result = [*self* compileFile:theScriptName
> inDirectory:temporaryFilesDirectoryName
> toDirectory:temporaryFilesDirectoryName];
> *if* (![result isEqualToString:@""])
>      {
> NSLog(@"There was an error compiling the file");
> *return* result;
>      }
> *return* @"";
> }
> 
> - (NSString*)compileFile:(NSString*)fileName
>               inDirectory:(NSString*)fromDirectoryPath
>               toDirectory:(NSString*)toDirectoryPath
> /// compiles the file using clang/
> {
> NSTask* compileTask = [[NSTask alloc] init];
> NSString* clangPath = [[NSBundlemainBundle] pathForResource:@"clang"ofType:@""inDirectory:@"Tools/bin/"];
>      [compileTask setLaunchPath:clangPath];
>      [compileTask setArguments:[NSArray arrayWithObjects:@"-c",concatenate3(fromDirectoryPath, fileName, @".m"),
> @"-isysroot",
> @"/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk",
> @"-o",
> concatenate3(toDirectoryPath, fileName, @".o"),
> *nil*]];
> NSPipe* errorPipe = [[NSPipe alloc] init];
> NSFileHandle* errorReader = [errorPipe fileHandleForReading];
>      [compileTask setStandardError:errorPipe];
>      [compileTask launch];
>      [compileTask waitUntilExit];
> NSString*  errorString = [[NSString alloc] initWithData:[errorReader readDataToEndOfFile]
> encoding:NSUTF8StringEncoding];
> 
> 
> *if* ([errorString length] != 0)
>      {
> NSLog(@"There was a Compilation error: %@", errorString);
> *return* errorString;
>      }
> *return* @"";
> }
> 
> - (*BOOL*)linkScriptFiles:(NSString*)theScriptName
> {
> NSString *applicationSupportDirectoryPath = [[NSFileManager defaultManager] applicationSupportDirectory];
> NSString* temporaryFilesDirectoryName = concatenate(applicationSupportDirectoryPath, @"/ImitateScriptSystem/TemporaryFiles/");
> 
> NSString* linkResult = [*self* linkTheScriptFilesToScriptName:theScriptName
> intoDirectory:concatenate(temporaryFilesDirectoryName, theScriptName)];
> *if* (![linkResult isEqualToString:@""])
>      {
> *if* (searchOfString(@"error", linkResult) != -1 || searchOfString(@"Error", linkResult) != -1 || searchOfString(@"ERROR", linkResult) != -1)
>          {
> NSLog(@"CASE 1 LINK ERROR");
> *return* *NO*;
>          }
> *else* *if* (searchOfString(@"warning", linkResult) != -1 || searchOfString(@"Warning", linkResult) != -1 || searchOfString(@"WARNING", linkResult) != -1)
>          {
> NSLog(@"CASE 2 LINK WARNING");
> *return* *YES*;
>          }
> *else*
>          {
> NSLog(@"CASE 3 UNKNOWN LINK PROBLEM");
> *return* *NO*;
>          }
> 
> 
>      }
> *return**YES*;
> }
> 
> - (NSString*)linkTheScriptFilesToScriptName:(NSString*)theScriptName intoDirectory:(NSString*)dir
> /// links the file using clang/
> {
> NSString *applicationSupportDirectoryPath = [[NSFileManager defaultManager] applicationSupportDirectory];
> NSString* temporaryFilesDirectoryName = concatenate(applicationSupportDirectoryPath, @"/ImitateScriptSystem/TemporaryFiles/");
> NSTask* linkTask = [[NSTask alloc] init];
> NSString* clangPath = [[NSBundlemainBundle] pathForResource:@"clang"ofType:@""inDirectory:@"Tools/bin/"];
>       [linkTask setLaunchPath:clangPath];
>       [linkTask setArguments:[NSArrayarrayWithObjects:
> concatenate4(temporaryFilesDirectoryName, @"/", theScriptName, @".o"),
> @"-framework",
> @"Cocoa",
> @"-framework",
> @"Foundation",
> concatenate(@"-F", temporaryFilesDirectoryName),
> @"-v",
> @"-isysroot",
> @"/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk",
> @"-bundle",
> @"-o",
> concatenate(dir, theScriptName),
> *nil*]];
> NSPipe* errorPipe = [[NSPipe alloc] init];
> NSFileHandle* errorReader = [errorPipe fileHandleForReading];
>      [linkTask setStandardError:errorPipe];
>      [linkTask launch];
>      [linkTask waitUntilExit];
> NSString*  errorString = [[NSString alloc] initWithData:[errorReader readDataToEndOfFile]
> encoding:NSUTF8StringEncoding];
> *if* ([errorString length] != 0)
>      {
> NSLog(@"There was a linking error: %@", errorString);
> *if* ((searchOfString(@"error", errorString) != -1) ||
>              (searchOfString(@"ERROR", errorString) != -1))
>          {
> *return* errorString;
>          }
> *else*
>          {
> *return*@""; /// ALLOW WARNINGS./
>          }
> *return* errorString;
>      }
> *return* @"";
> }
> 
> NSString* concatenate(NSString* x, NSString* y)
> {
> *if* (!x && !y) *return* @"";
> *else* *if*(!x) *return* y;
> *else* *if* (!y) *return* x;
> *return*[x stringByAppendingString:y];
> }
> 
> NSString* concatenate3(NSString* x, NSString* y, NSString* z)
> {
> *if* (!x) x = @"";
> *if* (!y) y = @"";
> *if* (!z) z = @"";
> *return*[[x stringByAppendingString:y] stringByAppendingString:z];
> }
> 
> NSString* concatenate4(NSString* w, NSString* x, NSString* y, NSString* z)
> {
> *if* (!x) x = @"";
> *if* (!y) y = @"";
> *if* (!z) z = @"";
> *if* (!w) w = @"";
> *return*[[[w stringByAppendingString:x] stringByAppendingString:y] stringByAppendingString:z];
> }
> 
> *int* searchOfString(NSString* x, NSString* str)
> ///searches for x within str, if not found returns -1/
> ///otherwise returns its location./
> {
> *if* ((*int*)[str length] == 0) *return* -1;
> *if* ((*int*)[x length] > (*int*)[str length]) *return* -1;
> NSRange myRange = [str rangeOfString:x];
> *if* (myRange.location != NSNotFound)
> *return* (*int*)myRange.location;
> *else**return*-1;
> }
> 
> *@end*
> *
> *
> 
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