Make debugging easier by printing relevant errors

[ShellCode33]

Hi ! Thanks for this amazing tool ! I came across an error and to be honest, debugging arm_now was an absolute nightmare... I spent almost 2 hours digging into the code just to realize the FS wasn't big enough...
This PR improves errors printing and should help future users to understand what's wrong with their setup

[SakiiR]

Hey @ShellCode33 there is issue with ur PR (Conflicts)

[ShellCode33]

It was indeed in conflict, I included a commit in the PR which shouldn't have been there. Should be ok now.

[SakiiR]

Hey buddy,

It seems to not work on MacOs :) Can u check ?

[SakiiR]

https://stackoverflow.com/questions/55043135/qemu-system-arm-redir-invalid-option

[ShellCode33]

This is not related to this PR but more to this one #36, you are probably using a pretty old version of qemu... Can't you upgrade it ? Otherwise the thing to do is to check qemu's version beforehand and use the appropriate parameter, which is kind of ugly :/

[SakiiR]

Sorry @ShellCode33 I don't understand, what is the new syntax ? --redir or -nic user,hostfwd=tcp::8080-:80

[SakiiR]

Here is my version of qemu-system-arm:

- tmux % qemu-system-arm --version                                                                                                                                                                                                                         
QEMU emulator version 4.1.0
Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers

[ShellCode33]

Oh ok I see ! You are still using the old qemu's -redir, do not clone my repo as is, it only contains this PR, not the other PR I've made about the ports redirection fix. But again, this PR is not about port redirection, it's just an errors printing improvement

Just to be clear :

• -redir is the old qemu's way to redirect a port, it has been removed in qemu 3.1.0
• -nic is the new way to redirect a port
• --redir is the command line parameter to give to arm_now to redirect a port