Fix msg client

[fbrausse]

Hi,

this set of changes does the following:

• fix message_client.c does not compile #5 by basically duplicating the session setup code from test/test_client.c

  axc/test/test_client.c

  Line 89 in 206bf43

  int client_setup_sessions(void ** state) {

  (2cafb15, 4187e64 and 54e8c17)
• fix various memory leaks in src/message_client (2cafb15) ...
• ... as well as in the main library (960429c)
• simplify the message_client's code (c77b01c)
• fix running into an endless loop in message_client on EOF of stdin (5e4abed)

Especially regarding items 1 and 3 I am not completely certain that this is the intended use of the API axc provides. I am relatively new to the Signal protocol itself, however, the message client en- and decryption now works between Alice and Bob.

Wrt. to the memory fixes on the library side (item 3 above), my assumption was that the library functions allocate this memory and therefore should also free it in order for user-code to be agnostic to future changes in the internals.

Please check carefully. I'm happy to reorder / squash or make other changes to this set of patches. Thank you!

[gkdr]

Hi, and thank you for your contribution!

Regarding the message_client.c: It was just a first POC for myself for when I had nothing that actually uses this library yet and was broken for a long time since I didn't think it's worth the time to repair it (and in general this repository is probably only useful as an implementation example to others). So if it works, I'm sure it's good!

I have recently noticed some potential memory management issues myself while working on something else, so you might have uncovered some of the same things. From a first glance, you found even more, and I'll have to have a closer look. I'm going to do this once I get to the computer I use for working on these projects, which unfortunately might take a little while, so sorry in advance.

[Neustradamus]

@fbrausse: What is the status of your PR?

[gkdr]

@Neustradamus, please stop commenting on every open pr. i understand you want to help, and let me tell you that this is the opposite of helpful. if you don't, i will have to find out how to prevent you from commenting. this goes for all repositories.

@fbrausse sorry, it's been such a long time that i forgot you made some very important contributions and did not in fact just fix the demo, like i thought i remembered from the title. be sure that i'm on it, though.

[gkdr]

i finally got to look at it, and the merging wasn't as bad as i feared 😬 it was a manual merge, and it looks like i have to close the PR manually too. thanks again for the contribution, @fbrausse!

[hartwork]

For anyone interested, this PR is included with commit 1c60f49 on branch dev by now.

[fbrausse]

Many thanks!