NSTask from sandboxed helper app fails with "Could not set sandbox profile data"

Question

I’m working on a Mac OS app composed of a main app and a helper :

Backup.app/
└── Contents
    ├── Library
    │   └── LoginItems
    │       └── BackupHelper.app
    ├── MacOS
    │   └── Backup

Backup.app: ask the user to select a path and save an app-scoped security bookmark. BackupHelper.app: Backup this path.

both Backup.app and BackupHelper.app are sandboxed.
The backupHelper app is registered to start at login using SMLoginItemSetEnabled.

When BackupHelper.app needs to access the bookmark saved by Backup.app,
I want it to call Backup.app (with some parameters) to get the final NSURL (the one with the applesecurityscope parameter)

One I try to start Backup.app using NSTask, It terminates with NSTaskTerminationReasonUncaughtSignal and I got this stacktrace :

Process:         Backup [18095]
Path:            /Applications/Backup.app/Contents/MacOS/Backup
Identifier:      Backup
Version:         1.0 (1)
Code Type:       X86-64 (Native)
Parent Process:  BackupHelper [18093]
Responsible:     BackupHelper [18093]
User ID:         501

Date/Time:       2013-11-04 10:23:06.016 +0100
OS Version:      Mac OS X 10.9 (13A603)
Report Version:  11
Anonymous UUID:  84A150C3-31C4-BE29-AAC9-338910633B1C

Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Exception Type:  EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes: 0x0000000000000001, 0x0000000000000000

Application Specific Information:
Could not set sandbox profile data: Operation not permitted (1)

Application Specific Signatures:
SYSCALL_SET_PROFILE

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libxpc.dylib                       0x00007fff9079c5a1 _xpc_runtime_init_once + 2482
1   libdispatch.dylib                  0x00007fff8e59c2ad _dispatch_client_callout + 8
2   libdispatch.dylib                  0x00007fff8e59c21c dispatch_once_f + 79 

When I try to start Backup.app directly it works fine and when I try to start another app with the same NSTask it works as well. Do you have any idea why it's not working specifically with Backup.app ?

Thanks !

Adamo

My app is sandboxed and runs (bundled) sub-processes using posix_spawn() talking to them over a text-based protocol. If you try and run one of these sub-processes on their own from the command line you get the same error. This relates to lack of a sandboxed environment on the command line. Perhaps you need to be using XPC? – Aun

As I understand, XPC requires Backup.app to be started, in my case that might not be the case. I read somewhere that posix_spawn() is not working well with sandboxed apps and the AppStore, any thoughts on this ? (I'll still try with it, thanks). Could it be an issue with the app signature ? (as it works for other apps than Backup.app) – Adamo

The reason I am using posix_spawn() is because that functionality is implemented in a cross-platform C++ library, and if it was Objective-C I would probably use NSTask. I haven't had a problem with it, per-se, as it works just fine, but it's surprising that these bundled sub-process executable then become unusable from the command line. I'm sure it's related to your issue and it might be the app signature that's causing the issue. – Aun

Does anyone have an update on this ? I am running against the same issue of "Could not set sandbox profile data: Operation not permitted (1)". Any pointer very welcome. – Confucianism