Clara BW How can I test an app built using NickelHook?

[liquido]

I have been learning about reverse engineering and trying to understand the Kobo shared library. I finally figured out what functions I need to hook into to achieve what I want.

I now want to either create a standalone app or provide an interface for it in NickelDBus. In either case, I need to utilize NickelHook. I have several questions with regards to that:

1. What happens if my changes cause segfault? This is the only thing I am worried about. I do not want my device to break because I did not properly assign a variable or something in the handle.
2. How can I test that my changes actually work without worrying about bricking my device?
3. Even if not bricking, how can I check logs etc to ensure that my feature actually works? Do I need SSH access or something?

Overall, I just want to understand the process of compiling and testing the application.

[sherman]

Hi, it's great to see another person having a go at Kobo dev.

1. If the library segfaults, generally the Kobo will reboot.
2. NickelHook has protections included to prevent boot loops. If the Kobo reboots before a timeout is reached, the library will not be loaded for the next boot. Even if a boot loop happens, it is still possible to reset the Kobo using the official recovery script. Unless you are messing with the Bootloader, Kernel or init scripts, it is almost impossible to brick a Kobo.
3. Telnet or SSH access is highly recommended. NickelHook provides functions to log to syslog, which you can read using logread. It is also possible to log to a file somewhere in /mnt/onboard as well.

Note the above is for devices running firmware 4.x ONLY.

EDIT: I see you have a Clara BW, this should be ok to work with, but you might want to check with others running the newest devices to make sure there are no gotchas to be worried about.

Have fun!