Android abstract unix domain sockets AddressKind correction

[NickAtAccuPS]

The prior check causes abstract unix domain sockets to return AddressKind::Unnamed instead of AddressKind::Abstract on Android.

Other than the immediately proceeding comment "macOS seems to return a len of 16 and a zeroed sun_path for unnamed addresses" the check as-implemented does not seem to have alternative explanation. I couldn't find an alternative explanation while stepping though git blame. I suspect the AddressKind::Unnamed nonzero check should instead be if macos, length 16, and zeroed array. @sfackler could you comment on this, the code as-is is the same from your initial addition of abstract uds support.

[rust-highfive]

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

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[00:05:07] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:05:08] tidy error: /checkout/src/libstd/sys/unix/ext/net.rs:217: line longer than 100 chars
[00:05:09] some tidy checks failed
[00:05:09] 
[00:05:09] 
[00:05:09] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:05:09] 
[00:05:09] 
[00:05:09] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:05:09] Build completed unsuccessfully in 0:02:04
[00:05:09] Build completed unsuccessfully in 0:02:04
[00:05:09] make: *** [tidy] Error 1
[00:05:09] Makefile:79: recipe for target 'tidy' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0c135dd7
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

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[NickAtAccuPS]

r? @sfackler

[sfackler]

Why are you looking for an alternative explanation? The check is for not Linux because BSDs share OSX's behavior.

[sfackler]

We have checks that addresses are unnamed as appropriate, and those should be running on Android as well: https://github.com/NickAtAccuPS/rust/blob/da6142c81057342d8d6686ae4078995aab73b5bc/src/libstd/sys/unix/ext/net.rs#L1747

Did you see this not working in practice? Maybe this behavior changed at some point in Android releases?

[pietroalbini]

Thanks for this PR! Changed the title to WIP so bors actually prevents merging until the prefix is removed from the title :) (also, highfive is down, assigned label+reviewer)

[NickAtAccuPS]

The check is for not Linux because BSDs share OSX's behavior.

That's the context I was missing.

The problem I'm seeing in the wild is that while libstd doesn't handle creating/pairing an abstract UDS, it does handle them correctly if UnixStream et al. are manually constructed with from_raw_fd() with an abstract namespaced socket fd on Linux. This is how mio_uds is currently implemented.

self.address() is used for the fmt::Debug and checks for abstract sockets correctly on Linux but incorrectly returns that the socket is unnamed on Android. This PR fixes that issue specifically.

Sorry that this wasn't clear from the first comment; I had forgotten that libstd doesn't support abstract socket creation.

I don't think the test_connect_unix_datagram() test is relevant to this PR; @sfackler did you mean to link to the abstract_namespace_not_allowed() test? Still that's just checking for connecting to an abstract UDS via libstd functions, not manually populating a UnixStream with a connected abstract socket fd as mio_uds demonstrates.

[sfackler]

Ah, I was thinking that the issue was failing to detect unnamed addresses, not abstract addresses.

[sfackler]

@bors r+

[bors]

📋 Looks like this PR is still in progress, ignoring approval

[pietroalbini]

@sfackler you need to r+ this again.

[kennytm]

@bors r=sfackler

[bors]

📌 Commit da6142c has been approved by sfackler

[bors]

⌛ Testing commit da6142c with merge 38e251b...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: sfackler
Pushing 38e251b to master...