BlueZ hci_le_set_scan_parameters() function fails in VC++ code - raspberry-pi3

I am running some well-known C++ sample code on Raspberry Pi 3 (running as a client on the latest Raspbian version) for communication with BLE devices (running as servers) from VS2017 C++ for Linux project in debug mode. My project compiles without errors and even warnings. I use the BlueZ library's HCI finctions. Please advise me why the call to the BlueZ hci_le_set_scan_parameters() function fails (returns -1). From
Here is the link to the original C++ code I use without any changes:https://github.com/carsonmcdonald/bluez-experiments/blob/master/experiments/scantest.c
Thank you in advance.

Besides requiring elevated privileges, there's also the possibility that your bluetooth controller is in an odd state. There are two ways to fix it:
Just wait
Use bluetoothctl
Run bluetoothctl as root (sudo bluetoothctl), then execute the following commands
agent on
default-agent
scan on
scan off
agent off
exit
That should be enough to kick your controller and get the HCI functions working again. But remember, you most likely have to have elevated privileges to execute those commands.

Related

Prevent custom windows kernel driver backup from running

I have a custom windows kernel driver I have compiled. I sign it with a test cert, create the cat file from the cdf, stamp the inx into a inf file, then load it with pnputil. I then create a software device with SwDeviceCreate so the OS will pair my driver and the driver. This works fine.
The problem is if i screw up something in the compilation and get something like an error code 39 (viewable in device manager), I do not see that error. Instead the OS seems to try to fix the error by loading the previously working version of the driver. In order to see that error, I have to purge the driver and device using pnputil /d oem42.inf along with a pnputil /remove-device, then restart my PC, that seems to fix the issue. This is difficult because it means i have to restart my PC every time i run a test. I know crashing a kernel driver can cause a panic anyway and cause me to restart, but there seems to be instances where this is not the case and the OS tries to rectify the issue without me (as it probably should).
So my question is this. Is there a way to completely purge my driver without a complete restart in-between installations/tests so I can correctly break it. I know I am suppose to use another machine and remote debug kernel drivers, but i do not have access to another machine right now that can support windows 11.

Applescript "mixed credentials" error

I asked this question over on the Apple Communities and got a grand total of ZERO responses. You guys seem a whole lot smarter, so thought I would ask here to see what you think.
An error has started occuring when I attempt to trigger an Applescript via an external process. The console error is as follows:
12/09/2012 11:01:39.205 osascript[269]: Scripting addition loading restricted to system domains because this process has mixed credentials (issetugid=0 r/e uid=501/0 gid=20/20)
When I run the script locally on the Mac(Mini - Mountain Lion 10.8.1) it works perfectly.
What is happening is as follows.
I have a MacMini as a music server in a home automation environment powered by a Crestron processor. The MacMini is connected to two zones, one via the Optical output and another to a DAC from one of the USB ports. When I selected "Listen to iTunes" in one of the two zones the controller sends a command via UDP to a program running on the MacMini which triggers the scripts to change to the appropriate audio out.
All was working well until yesterday when all of a sudden the program triggering the script, whilst reporting that it has executed the correct script correctly, isn't switching the output and the above message is appearing on the console.
I have read what I can on here and as such have reset the PRAM and SMC (all three dongs...) and deleted the script triggering program, run Clean My Mac and rebooted, all to no avail.
Can anyone help me with this, it has to be something simple given that it was working...surely? I haven't run an update or changed anything else that I can think of.....
Any and all thoughts and input would be greatly appreciated.
Thanks
Marc
From the error it seems that you have an add-on to applescript called a "Scripting addition" installed, and that's causing the error. Most likely you do not need this add-on to perform your applescript code. So I would remove all scripting additions from my system and see if the applescript still works.
Search your system for scripting additions... ~/Library/ScriptingAdditions and /Library/ScriptingAdditions.
If you do need to do something that the scripting addition is doing for you, then there's probably other ways to perform the same task without the add-on.

WFP kernel-mode driver's DriverEntry getting called differently on some machines?

I've added some code to the Windows Filtering Platform MSNMNTR sample for my own application, but it still has the same structure. I've compiled the driver and the application for Win8 64-bit and production-signed the driver. On the (virtual) machine that I built the code on, the sample works fine and monitors correctly. When I copy the inf, sys and exe to another machine, the sample does NOT monitor. Through traceview output, I can see that on the second machine, DriverEntry() is not called, therefore the flow controls are never set up. The two machines are running the release version of Win8. It doesn't appear to be an issue with my new code, since the driver works fine on machine #1, and it doesn't appear to be a signature problem because when I turn off signature enforcement on machine #2 I still have the problem. Both the release and debug versions of the code have the same issue. The steps I use to set up and run the code are below. What are some things that might cause this behavior?
Copy driver .pdbs to a folder for traceview.
Right-click .inf and choose "Install"
Run "net start msnmntr" from an elevated command prompt.
Start traceview as administrator.
Run "monitor monitor "C:\Program Files\Internet Explorer\iexplore.exe"" from an elevated command prompt.
P.S. I haven't put windbg on this yet, but I will update the question with the results as soon as I try it.
Edited to add: OK, I ran the kernel-mode debugger on both machines and saw a difference in behavior. First of all, DriverEntry does get called on both machines. I was mistaken about that. However, on the machine where the code works (i.e. monitors web traffic) DriverEntry gets called when monitor.exe is run (step 5 above), and on the machine where the code does not work DriverEntry gets called when "net start msnmntr" (step 3 above) is executed.
The problem was that I had not installed the callouts via "monitor addcallouts" on the second machine. Since this is a one-time step, I had forgotten I did it weeks ago on the original machine.

encounter 'Broken pipe' error only while using step-by-step debug with GDB

There is unix-socket server written on PHP (but I don't think it has something to with it). Client side is written on c++ and based on boost::asio library. When I launch program normally - everything works fine, except one (not related to socket communication) bug that I obviously want to debug. But when I start step-by-step debugging it I immediately receive 'Broken Pipe' error on the steps which perform write operations on sockets. If breakpoint is set up after socket write operation - everything work fine until the next attempt to step over the write func.
Spent whole day trying to solve this problem, but unsuccessfully...
Had anyone met the same trouble?
using GDB bundled with xCode 3.2.5 (64-bit) under OS X 10.6.7
GDB uses signals aggressively. If you want to install signal handlers, check out the following example:
https://github.com/sean-/Boost.Examples/blob/master/asio/timer/timer.cc#L106

Automating Win32 Driver Testing

Does anyone know ways of partially or fully automating driver test installation?
I am new to driver development and am used to more of a test-driven approach in higher level languages, so moving to the kind of environment where I can't easily test as I go has been a step up for me. I am using Virtual PC for my test environment and currently have to reset it, open device manager, choose the device, click through a bunch of "Are you really sure you wouldn't rather install one of these system drivers" type dialogs, then finally reset the test environment while restarting WinDbg in the host machine just as the test environment is booting up... argh.
After repeating this process many, many times already, surely there has to be a be a better way of doing this? What tools/methods/tricks do commercial driver developers use to run up their driver in a test environment?
Note, this isn't about unit testing drivers, I haven't got to that stage yet or know if it is even possible. This is just about firing up a test environment with WinDbg attached to make sure that some small change I may have done is doing what I expect.
It seems to me that a virtualization software + a "mock objects" (layering) approach (as suggested by Aaron Digulla) + scripts (as suggested by Sergius) can simplify device driver development.
But if you use Visual Studio to develop user-level applications, you can use it for kernel device driver development too with VisualDDK (+ VirtualKD to debug over a named pipe, which is faster than over a virtual COM port), which addresses specifically the annoyances that you mention; from its home page:
... This project brings the simplicity and
convenience of Windows application
development to the driver development
world. No more manual creation of
build scripts, copying of driver
files, installing drivers from INFs,
switching between WinDbg and the
source editor or waiting for seconds
after each step due to the extra-slow
virtual COM port. Just create a driver
project using a convenient Driver
Wizard, select a virtual machine, and
enjoy debugging your driver directly
from Visual Studio. Want to test a
change? Just normally press Shift-F5,
modify your driver, rebuild it and
launch again. VisualDDK will unload
the old driver, install the new one
and load it automatically and quickly.
Bored with WinDbg loading symbol files
for minutes and looking up symbols for
seconds? Just let VisualDDK optimize
this for you using its own DIA-based
symbol engine. Using C++/STLPort in
your drivers? VisualDDK will natively
visualize all STL containers and
strings, as good as Visual Studio does
for user-mode applications. ...
You can write some shell scripts (using sc.exe and devcon.exe) to automate deployment tasks (no opening device manager, clicking on buttons, etc). And make snapshot of the system ready to debug (needn't wait for system boot).
Don't forget to check your driver with DriverVerifier!
Example of my own script :)
sc create FsFilter type= filesys binPath= c:\FSFilterDrv.sys
sc start FsFilter
pause
sc stop FsFilter
sc delete FsFilter
Follow the advice I gave here. Basically, test as little as possible with the real system.
In your case, I've got another tip: Virtual PC is using a virtual hard disk (that's probably a file on your real hard disk).
You don't need to install your driver, you can simply replace the new files in the virtual hard disk. This is often not possible in the running system but in a virtual system, you can open the virtual disk file and change it (since Windows isn't locking the files in it).
I'm not sure about Virtual PC but other emulators come with tools to work with virtual disk images. If VPC can't do it, check out VirtualBox.
It all depends a little on what kind of driver you are writing. But in many cases, writing an appropriate makefile (or something similar) that handles driver installation, start/stop, and launching of a test harness can already be good enough.
I also configure all of my test machines to automatically logon (AutoAdminLogon), map net drives, and launch an appropriate command prompt after startup. Running a specific test is then a matter of typing in a single command only.
One word concerning VirtualPC: VirtualPC is very handy for kernel mode development, but do not forget that it emulates a uniprocessor machine only -- so be sure to regularly test the code on a multiprocessor machine as well. That said, the VHD trick may seem handy, but it somewhat ties you to Virtual PC -- writing appropriate scripts that equally work on VirtualPC as on a real machine therefore seems a better approach to me.
Finally, consider it a shameless plug, but if you are looking for a unit testing framework for Windows kernel mode code, I have written one: cfix.
I think the DevCon utility (described in this OSR Online article) will help you. You should be able to setup batch files that do the job on one click.
It's free to sign up with osronline.com, and you'll probably have to sign up to get to that article. And if you are writing drivers, you WANT to sign up. These guys have been doing this for a long time, and there's a LOT of really good info on that web site.

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