I use NSTask to run my helper application. On 99% one my customer systems this works fine, but two got back to me letting me know it doesn't. One of them was nice enough to let me look into the issue per remote desktop.
I tried a lot of different NSPipe/NSFileHandle combination for StandardOutput/StandardError to make sure the problem is not related filling up these buffers. Example 1 and 2. My guess is that it is not related because it works fine on so many systems and _dyld_start is too early on in the application lifecycle to fill up StandardOutput/StandardError.
Other notes about the problem:
Launching the helper app from the terminal works fine.
Attaching and detaching the gdb on the stuck process and after-worth it works fine and when it finished NSTask picks up work after -waitUntilExit.
Using fork(2) and execv(3) instead of NSTask is able to launch and run the helper fine.
The parent process is sandboxed but I think previous reports where non-sandboxed on Mac OS X 10.6/10.7.
Screenshot of the process Sample from Activity Monitor:
Any clues or debugging tips to figure out why the helper is stuck in _dyld_start are welcome!
Since nobody answered, I am throwing a few ideas. Maybe one of them is the answer – only guessing – but since clues and tips are welcome, you could take a look at:
the list of the loaded libraries in the crash dump (there may be a clue there)
any error that would happen in the child process (after the fork). However, I see why it could be difficult to get back any post-fork error.
If I recall correctly, NSTask calls posix_spawn(2). This may be a clue, since using fork(2) and execv(3) seems working, you could focus on the differences between NSTask and the non-blocking alternative. Clearly, something is happening at the very beginning that prevents the child from executing properly.
Are you sure it is stuck and not crashed? As far as the user could tell, your app your app wouldn't look like it crashed. Only the child process would crash.
As a last resort, you could try to look for any Mach exception occuring (if
any, that would mean an error, which you wouldn't be able to
recover anyway. But it would provide valuable clues nonetheless).
You can tell willing custommers to send you their sysdiagnose. To this goal, ask them to hit Command + Option + Control + . + Shift to wait a few minutes. Soon after, their finder should pop a window to reveal a file named: sysdiagnose_timestamp_.tar.gz. Kindly ask them to mail it to you. Mine is around 5 MB. More details on the sysdiagnose man page.
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I'm trying to troubleshoot an issue on watchOS.
I'm not sure how to reproduce the problem I'm seeing, but I do encounter it occasionally during testing on a real device in the wild, so I'm trying to use os_log in order to diagnose the problem after the fact.
As a first step, to make sure I understand how how to write to the log and access it later, I've attempted to log an event any time the app first loads.
In the ExtensionDelegate.swift file for my app, I added this:
import os.log
extension OSLog {
private static var subsystem = Bundle.main.bundleIdentifier!
static let health = OSLog(subsystem: subsystem,
category: "health")
}
Then, I updated the applicationDidBecomeActive delegate function with this:
func applicationDidBecomeActive() {
os_log("App Started",
log: OSLog.health,
type: .error)
}
I know it's not really an error message, but from what I've read, messages that are not .error are not written to saved to the log for later. I want to make sure it gets written to the log like a real error would.
I installed the sysdiagnose profile, then installed the the most recent version of my app.
After testing the app for the day, I attempted to export the file. Following the instructions I've found elsewhere, I produced a sysdiagnose on Apple Watch by holding the Digital Crown and Side button for two seconds (and felt the haptic feedback when I released).
Then, I put the watch on the charger for a few minutes per the instructions here, which recommended 15 minutes.
I opened the Watch app on my paired iPhone, then went to General > Diagnostic Logs and downloaded the sysdiagnose from Apple Watch, and sent it to my computer with AirDrop.
This gave me a tarball file (for example, sysdiagnose_2021.03.05_17-01-57-0700_Watch-OS_Watch_18S801.tar.gz). Once I decompressed that, I had a folder of lots of files and subfolders.
After poking around in this folder, I figured my best bet was to look in the system_logs.logarchive file. I opened that in the macOS Console app, set the Showing dropdown to All Messages, and looked around the time I opened the app. I didn't see any log output from my app.
I also filtered for "App Started" (the log message from my app) and didn't find anything.
Then, I filtered by category for "health" and didn't find the event I had logged.
Is system_logs.logarchive the correct place to be looking for the log output from my app?
If not, where should I be looking? Or what am I doing wrong?
I really want a better understanding of how I can log messages on Apple Watch so I can view them later so I can make my Apple Watch apps more robust, but I'm at a dead end.
Am I looking in the wrong place? Or am I setting up the logging wrong? Or is it something else? I would appreciate any guidance about this!
According to the Apple Dev Forms, sysdiagnose allows you to view the logs on your apple watch.
It has been a little while, let's say 3 weeks, that the initial line of my prompt is b0:2a:43:7d:d1:3d:~ eduardoj$ instead of passatempo:~ eduardoj$. It has been like this, for every new sessions, even after rebooting.
But just new, a few of the sessions showed passatempo:~ eduardoj$. After noticing it again I decided to search what would that be. Having both tabs of my terminal still opened I ran
echo $HOSTNAME, which returned, respectively b0:2a:43:7d:d1:3d.hitronhub.home and
passatempo.local.
I tried to google hitronbub.home and nothing made sense. I also saw some results here on stackoverflow that somehow related it to docker. Then I stoped all my containers and killed my daemon. After that, the new sessions I opened were still presenting the same b0:2a:43:7d:d1:3d.hitronhub.home.
Does anyone know what is it? Or, how could I track where it is causing it?
Currently i'm working on a security monitoring app that continuously monitor new processes created.
For that im using wim and event watcher, witch works fine in VB.NET.
But there are 2 features that im missing.
I need to monitor process API calls, and I've been searching the web like mad, and come up empty.
Basically i need to monitor process WaitForSingleObject, LoadLibraryA, CreateProcessW and WriteProcessMemory. And registry access/changes as well.
Im hoping this can be done without a system wide hook, but form what i can find, it cannot be done via WMI.
So the question is, how to, and what can i do with managed code.
I'm gonna focus on the second point as i don't have experience on your first.
For checking if a process is signed i am using the sigcheck.exe from Mark Russinovich, because of the various methods it uses to verify files. Some are catalogsigned, some have the key embedded, there is iirc another weird method. There is no easy way to do it yourself. Had weird false detections with trying self-built methods to cover all possibilities. Hope that info helps
I envisage I'll run into problems as i haven't done this before.
I'm thinking that I can either define a date at the start of the method or initialise a class.
Then at the end of the method, call the commit method, which will write the time taken about with some sort of code to determine where the measurement was made.
Since you're crashing before the app finishes launching, so no code is going to fix this. If TestFlightApp isn't working, any other code-based solutions are likely to have the same problem.
As #dasblinkenlight noted, NSLog timestamps, so that's a really easy first step. Then you need to get the logs.
If possible, have your user install and run the iPhone Configuration Utility. Have her connect her device and select it from the Devices list. Then select Console and "Save Console As..." She can then mail it to you.
I am working on Objective C to develop an app in I Pad. When I run the program its getting executed in Simulator of IPad. When I do the same connecting the device then I am facing an Error as GDB:Data Formatters temporarily unavailable,will re-try after a 'continue'.
Someone guide how to solve this issue.
Regards,
Vani.
This can be because of several reasons:
Memory issue. Try running your app with instruments to check
When it is unable to find a linked in shared library at launch time.
Also you can try running in a different target xcode and check if that works
Check all you breakpoints. In the Debugger window, click on "Show Breakpoints" and see if there are any unusually placed breakpoints
I also got the same problem in cocoa application.
Take a look at Data Formatters temporarily unavailable, will re-try after a 'continue'.
"Data Formatters temporarily unavailable, will re-try after a
'continue'." means that something has gone so horribly wrong in your
code that even the debugger bailed. As dragyn said, this usually
involves some form of rapid object creation or recursion calling. Add
a few NSLog lines into your code to help you see how far your code is
getting and where it might be looping/calling itself.