fix, unix socket bind should be only used in passive mode

[cscps]

---

name: Pull request
about: Propose changes to the code
title: ''
labels: ''
assignees: ''

1. Are you opening this pull request for bug-fixes, optimizations or new feature?

bug-fixes

2. Please describe how these code changes achieve your intention.

unix socket bind should be only used in passive mode
When using non-blocking socket as client, we should not close fd for EINPROGRESS error

3. Please link to the relevant issues (if any).

4. Which documentation changes (if any) need to be made/updated because of this PR?

4. Checklist

• I have squashed all insignificant commits.
• I have commented my code for explaining package types, values, functions, and non-obvious lines.
• I have written unit tests and verified that all tests passes (if needed).
• I have documented feature info on the README (only when this PR is adding a new feature).
• (optional) I am willing to help maintain this change if there are issues with it later.

[panjf2000]

Good catch! please also make the same change to tcp_socket.go and udp_socket.go

[panjf2000]

Also, I wonder why the system call - bind() didn't raise an error when it's called by client socket.

[cscps]

the client of gnet is sync using built in net.Dial, it will never call this function. I found it when implementing my own async client code

[panjf2000]

the client of gnet is sync using built in net.Dial, it will never call this function. I found it when implementing my own async client code

You're right, I forgot that. Now please apply the same code changes to the other files.

[cscps]

ok, I foget :(

[panjf2000]

Please take a look at these review comments.

[codecov]

Codecov Report

Merging #373 (4331027) into dev (8d921f9) will decrease coverage by 0.68%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev     #373      +/-   ##
==========================================
- Coverage   72.04%   71.36%   -0.69%     
==========================================
  Files          13       13              
  Lines        1381     1390       +9     
==========================================
- Hits          995      992       -3     
- Misses        318      326       +8     
- Partials       68       72       +4     

Flag	Coverage Δ
unittests	71.36% <ø> (-0.69%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
connection.go	65.61% <0.00%> (-3.00%)	⬇️
client.go	50.65% <0.00%> (+0.32%)	⬆️

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[panjf2000]

Thanks~

[zhu121]

@ccssrryy
There is a question, EINPROGRESS should occur when connect() is called, and when fd is non-blocking; but why the code change is to judge this error when socket() is called

[cscps]

@ccssrryy There is a question, EINPROGRESS should occur when connect() is called, and when fd is non-blocking; but why the code change is to judge this error when socket() is called

The error check is in defer which is checking returned error, not only for socket() call