Only register `WSACleanup` if `WSAStartup` is actually ever called #85595

CDirkx · 2021-05-23T02:40:17Z

Fix for #85441.

Because WSACleanup appears in cleanup currently WS2_32.dll is always linked, even if no network functionality is ever used.
To prevent this, WSACleanup has to only appear in init, hence the workaround of registering it in a static.

If anyone knows a cleaner solution, let me know.

rust-highfive · 2021-05-23T02:40:20Z

r? @joshtriplett

(rust-highfive has picked a reviewer for you, use r? to override)

nagisa · 2021-05-23T11:58:50Z

library/std/src/sys/windows/net.rs

@@ -28,6 +28,10 @@ pub struct Socket(c::SOCKET);

 static INIT: Once = Once::new();

+// Workaround to prevent linking to `WS2_32.dll` when no network functionality is used.
+// See issue #85441.
+static mut CLEANUP: Option<unsafe extern "system" fn() -> i32> = None;


Consider using SyncLazy/SyncOnceCell for the INIT.

I combined the two statics in a SyncOnceCell.

nagisa · 2021-05-23T14:05:24Z

This seems okay to me. Is there any way a test could be written for this?

klensy · 2021-05-23T14:36:06Z

This seems okay to me. Is there any way a test could be written for this?

dumpbin.exe /dependents empty.exe

For example from issue, output will be:

Microsoft (R) COFF/PE Dumper Version 14.28.29914.0
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file empty.exe

File Type: EXECUTABLE IMAGE

  Image has the following dependencies:

    WS2_32.dll
    KERNEL32.dll
    VCRUNTIME140.dll
    api-ms-win-crt-runtime-l1-1-0.dll
    api-ms-win-crt-math-l1-1-0.dll
    api-ms-win-crt-stdio-l1-1-0.dll
    api-ms-win-crt-locale-l1-1-0.dll
    api-ms-win-crt-heap-l1-1-0.dll

  Summary

        1000 .data
        1000 .pdata
        7000 .rdata
        1000 .reloc
       19000 .text

we can grep output, but this is ugly.

CDirkx · 2021-05-23T14:57:39Z

I could add a run-make test to inspect a produced binary, however I don't know what tool to do that with: Is dumbbin.exe available on CI? Is there an already available tool that can show loaded dlls?

klensy · 2021-05-23T15:01:06Z

dumpbin is visual studio component, which included in github runner, i guess, but maybe there already some tools used for checking linked libraries\symbols in tests.

klensy · 2021-05-23T15:11:20Z

Test no-dllimport-w-cross-lang-lto looks promising, perhaps we can check that ws2_32 symbols not exist in exe.

CDirkx · 2021-05-24T22:08:15Z

I added a run-make test using objdump which I believe should be available on CI as well.

klensy · 2021-06-06T04:45:50Z

Works, at least under x86_64-pc-windows-msvc.

nagisa · 2021-06-06T15:06:58Z

r? @nagisa
@bors r+

Thanks!

bors · 2021-06-06T15:07:00Z

📌 Commit f798596 has been approved by nagisa

Only register `WSACleanup` if `WSAStartup` is actually ever called Fix for rust-lang#85441. Because `WSACleanup` appears in `cleanup` currently `WS2_32.dll` is always linked, even if no network functionality is ever used. To prevent this, `WSACleanup` has to only appear in `init`, hence the workaround of registering it in a static. If anyone knows a cleaner solution, let me know.

GuillaumeGomez · 2021-06-06T23:05:44Z

Failed in #86079.

@bors: r-

CDirkx · 2021-06-07T00:14:31Z

Good news, using objdump works on CI. Still figuring out how to reproduce the failure under x86_64-pc-windows-gnu.

crlf0710 · 2021-07-09T11:07:26Z

@CDirkx Ping from triage, any updates on this?

CDirkx · 2021-07-09T12:25:29Z

I had trouble getting the tests to run under x86_64-pc-windows-gnu on my machine in order to debug the problem on that platform. I'll try again this weekend though.

eddyb · 2021-08-08T12:20:50Z

library/std/src/sys/windows/net.rs

@@ -26,26 +26,31 @@ pub mod netc {

 pub struct Socket(c::SOCKET);

-static INIT: Once = Once::new();
+static WSA: SyncOnceCell<unsafe extern "system" fn() -> i32> = SyncOnceCell::new();


Could this be named WSA_CLEANUP? Or otherwise wrap the fn pointer in a struct - as it stands, the WSA name doesn't make it obvious what the fn pointer is supposed to be.

JohnCSimon · 2021-09-13T02:00:33Z

Ping from triage:
@CDirkx Can you please post your status on this PR?

nagisa · 2021-10-02T18:39:03Z

I looked at the build failure. I believe this is likely related to the fact that the gnu targets have function_sections disabled

rust/compiler/rustc_target/src/spec/windows_gnu_base.rs

Lines 66 to 67 in 21e1cd9

    
           // FIXME(#13846) this should be enabled for windows 
        
           function_sections: false,

thus preventing the linker from removing the references to various networking calls, which then pull in the undesirable dll.

I don't think re-enabling the function sections is going to be feasible, so we should only run that test on -msvc targets...

Since Christiaan seems to be away since at least July, I'm going to close this and open a fixed PR.

mati865 · 2021-10-02T20:40:17Z

FWIW I think it's not an issue with -ffunction-sections but rather issue with -Wl,--gc-sections which is buggy in binutils when targetting MinGW.
function_sections: true works fine when using LLVM toolchain for MinGW.

Only register `WSACleanup` if `WSAStartup` is actually ever called See rust-lang#85595 Fixes rust-lang#85441

rust-highfive assigned joshtriplett May 23, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 23, 2021

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CDirkx force-pushed the win-linkage branch from fb56643 to b469f20 Compare May 23, 2021 13:59

CDirkx added 2 commits May 24, 2021 23:58

Only register WSACleanup if WSAStartup is actually ever called

c3140e7

Add test for checking if WS2_32.dll is linked

f798596

CDirkx force-pushed the win-linkage branch from b469f20 to f798596 Compare May 24, 2021 22:06

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 6, 2021

GuillaumeGomez mentioned this pull request Jun 6, 2021

Rollup of 7 pull requests #86079

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nagisa closed this Oct 2, 2021

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Only register WSACleanup if WSAStartup is actually ever called #89472

Merged

Manishearth added a commit to Manishearth/rust that referenced this pull request Oct 4, 2021

Rollup merge of rust-lang#89472 - nagisa:nagisa/wsa-cleanup, r=dtolnay

43c4355

Only register `WSACleanup` if `WSAStartup` is actually ever called See rust-lang#85595 Fixes rust-lang#85441

Manishearth added a commit to Manishearth/rust that referenced this pull request Oct 4, 2021

Rollup merge of rust-lang#89472 - nagisa:nagisa/wsa-cleanup, r=dtolnay

e021a10

Only register `WSACleanup` if `WSAStartup` is actually ever called See rust-lang#85595 Fixes rust-lang#85441

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Only register `WSACleanup` if `WSAStartup` is actually ever called #85595

Only register `WSACleanup` if `WSAStartup` is actually ever called #85595

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Only register WSACleanup if WSAStartup is actually ever called #85595

Only register WSACleanup if WSAStartup is actually ever called #85595

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Only register `WSACleanup` if `WSAStartup` is actually ever called #85595

Only register `WSACleanup` if `WSAStartup` is actually ever called #85595

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