need binutils-gold for crowdsec package (GO)

[erdoukki]

I need binutils-gold for building Crowdsec for OpenWrt !

I already get it on OpenWrt host, for POC ;
https://discourse.crowdsec.net/t/usr-bin-ld-cannot-find-ldl/143

root@ultra:~/binutils-2.36# ldd.gold --version
GNU gold (GNU Binutils 2.36) 1.16
Copyright (C) 2021 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.

now I try to crossbuild a Package (before PR) on an Ubuntu host...

Any one can help me on this, please ?

References :
http://llvm.org/docs/GoldPlugin.html

Edit ; https://forum.openwrt.org/t/usr-bin-ld-cannot-find-ldl/90987/6

[erdoukki]

I get the cross build to work with :

[*] Advanced configuration options (for developers)  --->
[*]   Toolchain Options  ---> 
Binutils Version (Binutils 2.34)  --->
(--enable-gold --enable-plugins) Additional binutils configure options

which gives me (with grep .config) :

CONFIG_EXTRA_BINUTILS_CONFIG_OPTIONS="--enable-gold --enable-plugins"

But I cannot get it in predefined value of my Makefile !
something like :
#16244 (comment)

  PKG_CONFIG_DEPENDS:= \
  	@CONFIG_EXTRA_BINUTILS_CONFIG_OPTIONS="--enable-gold --enable-plugins"

How can I tell my Makefile to add this extra binutils config options ?

It's a requirement for ARM build of GO SQLITE3 included in CrowdSec !
https://discourse.crowdsec.net/t/usr-bin-ld-cannot-find-ldl/143/37

[erdoukki]

May be something more like:

PKG_BUILD_DEPENDS:= \
 	BINUTILS:CONFIG_EXTRA_BINUTILS_CONFIG_OPTIONS=\"--enable-gold --enable-plugins\"

[erdoukki]

Stuck on this !
I have tried some differents possible tweaks…
Is it only possible to modify .config from a package Makefile ?
Are the CONFIG sections checks at build only time ?

[erdoukki]

I need to use this commit openwrt/openwrt@19a6b0f

I want to use and configure from the package Makefile

[erdoukki]

From https://github.com/mwarning/openwrt-examples

HOST_CONFIGURE_ARGS: Similar to CONFIGURE_ARGS, but used when build for the host system architecture. This is needed for building the build tools.

so, setting HOST_CONFIGURE_ARGS would be sufficient ?

HOST_CONFIGURE_ARGS += \
	--enable-gold \
	--enable-plugins

[erdoukki]

I suppose that I need to do something like the select for a boolean value, but for a string I do not get success !

[erdoukki]

@jefferyto
Do you have advice about gold linker support for CGO requirements on ARM64 ?
I will wrote a patch for binutils to support gold-linker and make a PR on OpenWrt ToolChain…

[jefferyto]

Many Go programs here are compiled with CGO enabled and for all supported platforms (including arm64). Can you point to where you specifically need the gold linker?

[erdoukki]

The problem is with the link, only on arm architecture, of go-sqlite3 with crowdsec.
https://github.com/mattn/go-sqlite3
This make a run error without CGO

root@ultra:~# cd go-sqlite3/
root@ultra:~/go-sqlite3# CGO_ENABLED=1 GOOS=linux GOARCH=arm64 go build
root@ultra:~/go-sqlite3# cscli -c /etc/crowdsec/config.yaml machines add auto
FATA[16-07-2021 07:22:49 PM] unable to create new database client: failed creating schema resources: Binary was compiled with 'CGO_ENABLED=0', go-sqlite3 requires cgo to work. This is a stub

and this make a link error with CGO

root@ultra:~/crowdsec# CGO_ENABLED=1 GOOS=linux GOARCH=arm64 make release
/root/crowdsec/platform/linux.mk:5: Building for linux
rm -f crowdsec
go build -ldflags "-s -w -X github.com/crowdsecurity/crowdsec/pkg/cwversion.Version="v1.1.1" -X github.com/crowdsecurity/crowdsec/pkg/cwversion.System=linux -X github.com/crowdsecurity/crowdsec/pkg/cwversion.BuildDate=2021-07-17_10:16:25 -X github.com/crowdsecurity/crowdsec/pkg/cwversion.Codename=alphaga -X github.com/crowdsecurity/crowdsec/pkg/cwversion.Tag="1610255cbdbb901435d399f8fd533d7267a24adf" -X github.com/crowdsecurity/crowdsec/pkg/cwversion.GoVersion="1.16.5"" -o crowdsec -v
# github.com/crowdsecurity/crowdsec/cmd/crowdsec
/usr/lib/go-1.16/pkg/tool/linux_arm64/link: running gcc failed: exit status 1
collect2: fatal error: cannot find 'ld'
compilation terminated.

make[1]: *** [Makefile:20: build] Error 2
make: *** [Makefile:91: crowdsec] Error 2

[jefferyto]

If the issue really is go/gcc is wanting to use the gold linker but cannot find it, then I am reasonably sure there is a way to tell go/gcc not to use the gold linker. (I doubt this package is doing anything that really requires the gold linker.)

But instead of spending tons of time debugging this for you, I am going to suggest you change your makefiles to use the default Go package build mechanism provided by golang-package.mk instead of using crowdsec's makefile build. Most Go packages in this repo use this default build mechanism (and there are comments at the top of golang-package.mk that explain all the configuration variables). I consider not using this default build mechanism to be for advanced users only.

[erdoukki]

I will give a try to better enhancing the usage of goland-pacakage.mk for building crowdsec package...

but the problem is not the linker is not found, but that without gold linker, the linking just not works on arms !

I will try to debug (again) this issue.

[jefferyto]

I found one case where the Go compiler will switch to the gold linker for arm, when it is building code for dynamic linking. The Go compiler will do dynamic linking if -buildmode=shared or -buildmode=plugin (or -linkshared) is specified on the command line, or if it thinks the program it is compiling will (dynamically) load plugins. And I believe it figures out if the program will load plugins by looking to see if the plugin package is used.

In crowdsec I found one place where the plugin package is used, but from the code (and code comments) it appears that it is not doing real plugin loading. I believe if you patch that code to remove references to the plugin package, then the Go compiler will not switch to the gold linker for arm.

[erdoukki]

@jefferyto, thanks for your analysis, I am not a Go expert... ;-)
I have removed the 2 references to plugin, and the compilation still works !
Some small tests give the tools look also to still works !
I have pushed the modified sources with a new patch to see if the toolchain will get it compile on GITHUB-CI...
I will give also an issue at CrowdSec GITHUB.