Buffer overflow in toggly code sample

[loicpoulain]

In the Linux User Guide for Dragon Board (P22/26):
https://github.com/96boards/documentation/blob/master/ConsumerEdition/DragonBoard-410c/Guides/LinuxUserGuide_DragonBoard.pdf

The toggly src code define MAX_BUF as 10 bytes.
However this define is used to allocate buffers which need more memory in Write_GPIO and Read_GPIO functions. (snprintf).

This leads to stack corruption for the sample but also for users who base their own code on this sample.
https://discuss.96boards.org/t/bus-error-working-with-gpios/2704/6

A quick fix would be to define MAX_BUF as 100.
#define MAX_BUF 100

[Mani-Sadhasivam]

@loicpoulain Agree with you. Probably that was due to bad coding practice I'd say.

Thanks for pointing out.

@sdrobertw Any way to update the doc?

[fixxxxxxer]

@loicpoulain

This user guide was written by a third party and provided to us by a partner. This is the exact reason why I do not like static documentation as we do no own the raw doc. If you feel like having some doc fun 😃 , it would be really cool to turn that small section of the user guide into an individual doc (markdown) within the DB410c "guides" section.

https://github.com/96boards/documentation/tree/master/ConsumerEdition/DragonBoard-410c/Guides

Feel free to fork, create the new guide, and submit a PR. Much appreciated for noting this!

[loicpoulain]

@sdrobertw

I agree, but what about updating the pdf value as a short term fix.
#127

[fixxxxxxer]

@loicpoulain

I have accepted your PR, can we please close this issue if you feel it has been resolved.

Thanks!