Add error handling for close socket

[maks-mishin]

• Development branch: master

• Issues fixed: add error handling for correct closing of socket s because of return with close socket leads to descriptor leak(CWE-403).

• Brief description of code changes: added goto label with correct exit from function if necessary.

[ProjectMutilation]

@maks-mishin this isn't correct, mark of error_handling must be after return 0, now the function always return -1
probably you should added variable int ret and initialize it 0, and in error cases

    ret = -1;
    goto error_handling;
    ...
    error_handling:
        close(s);
        return ret;

p.s. not memleak, file descriptor leak(CWE-403)

[maks-mishin]

@ProjectMutilation, thanks for comments and advice.
I will fix it in the next commit.

[bmah888]

Thanks for the PR and comments! Plugging this file descriptor leak is definitely a good thing. I'm thinking about the use of the variable ret, it's only defined in one place (and only ever initialized to -1), and we only reference the value of ret in the two error exit cases. I'm not sure that's much better than just returning with the numeric literal -1.

I'm going to approve this for merging as-is, and going to sit on it a little bit to see if we want to iterate this a bit or not. The code change is definitely an improvement.