On Tue, Jan 7, 2020 at 7:10 AM Karthik Krishnamurthy <karthik3...@gmail.com> wrote: > > I did some more digging on the web and landed on this Go issue where you had > a comment: https://github.com/golang/go/issues/18123#issuecomment-264590075. > > The original issue is related c-archive buildmode, but reading further on > that thread, I am guessing that even for Go shared libraries built with > c-shared buildmode, invoking a plugin doesn't work due to multiple Go > runtimes being loaded. > > This comment: > https://github.com/golang/go/issues/18123#issuecomment-469111906 has a demo > that resembles my situation. > > Given all this, I am thinking that native C shared library -> Go shared > library -> Go plugin is an unsupported situation. Am I missing something?
I doubt it. Sorry for not being clear in my earlier reply: it's definitely unsupported. I was speculating as to whether it might be possible to make it work if you wanted to dig into the linker. Ian > On Tuesday, January 7, 2020 at 6:20:50 AM UTC-8, Ian Lance Taylor wrote: >> >> On Mon, Jan 6, 2020 at 11:54 PM Karthik Krishnamurthy >> <karth...@gmail.com> wrote: >> > >> > This is probably an unusual situation, but I am working on a product that >> > has the following chain of invocation. >> > >> > C (native shared library libfoo.so) -> Go (c-shared libbar.so) >> > >> > So basically, a native C shared library invokes a -buildmode=c-shared type >> > Go shared library. This interaction works just fine. >> > >> > However, we are augmenting libbar.so (Go shared library) to invoke a >> > Go-style plugin (libplugin.so) using Go's plugin package. The very first >> > attempt of this, failed like this: >> > >> > fatal error: runtime: no plugin module data >> > >> > >> > goroutine 17 [running, locked to thread]: >> > runtime.throw(0xf72b5cc4, 0x1e) >> > /usr/local/go/src/runtime/panic.go:774 +0x70 fp=0xc64d1b48 >> > sp=0xc64d1b34 pc=0xf71bfdd0 >> > plugin.lastmoduleinit(0xc648e5e0, 0x1001, 0x1001, 0xc64823e8, 0x95b9588) >> > /usr/local/go/src/runtime/plugin.go:20 +0xa50 fp=0xc64d1bd4 >> > sp=0xc64d1b48 pc=0xf71c1420 >> > plugin.open(0xc64a60c0, 0x26, 0x29, 0xc64a6060, 0x2a) >> > /usr/local/go/src/plugin/plugin_dlopen.go:77 +0x388 fp=0xc64d1d2c >> > sp=0xc64d1bd4 pc=0xf7275ad8 >> > plugin.Open(...) >> > /usr/local/go/src/plugin/plugin.go:32 >> > zero/base/interfaces.glob..func1(0xc64a60c0, 0x29, 0xf72b2610, 0x11, 0x29, >> > 0x0, 0xf719e2e5, 0xf71d958c) >> > /app/base/interfaces/plugin.go:12 +0x2e fp=0xc64d1d68 sp=0xc64d1d2c >> > pc=0xf7276cbe >> > zero/base.glob..func4(0xf7759c60, 0x21, 0xf7357f80, 0xc64823e0, >> > 0xc64a8445, 0x5, 0xf, 0xe, 0xd, 0xd) >> > /app/base/zl_helper.go:28 +0xb4 fp=0xc64d1d9c sp=0xc64d1d68 >> > pc=0xf72ac554 >> > main.glob..func10(0xffa1e800, 0x2, 0x2, 0xf7759c60, 0x21, 0xf775ac60, >> > 0x1b, 0x15, 0xc648e5c0, 0x5, ...) >> > /app/dec/dec.go:328 +0x7a fp=0xc64d1dd8 sp=0xc64d1d9c pc=0xf72aeb0a >> > main.glob..func11(0xffa1e800, 0x2, 0x2, 0xf7759c60, 0x21, 0xf775ac60, >> > 0x1b, 0x15, 0xc6496040, 0x5, ...) >> > /app/dec/dec.go:368 +0xa3 fp=0xc64d1e34 sp=0xc64d1dd8 pc=0xf72aee13 >> > main.Decorate(0xffa1e800, 0x2, 0x2, 0xf7759c60, 0x21, 0xf775ac60, 0x1b, >> > 0x15, 0xc6436000) >> > /app/dec/dec.go:98 +0x1f3 fp=0xc64d1eac sp=0xc64d1e34 pc=0xf72ad0b3 >> > main._cgoexpwrap_079f3b2ec7da_Decorate(0xffa1e800, 0x2, 0x2, 0xf7759c60, >> > 0x21, 0xf775ac60, 0x1b, 0x15, 0x0) >> > _cgo_gotypes.go:79 +0x95 fp=0xc64d1ef4 sp=0xc64d1eac pc=0xf72ace15 >> > runtime.call64(0x0, 0xffa1e72c, 0xffa1e79c, 0x24, 0x0) >> > /usr/local/go/src/runtime/asm_386.s:571 +0x31 fp=0xc64d1f38 >> > sp=0xc64d1ef4 pc=0xf71e9ad1 >> > runtime.cgocallbackg1(0x0) >> > /usr/local/go/src/runtime/cgocall.go:314 +0x162 fp=0xc64d1fb0 >> > sp=0xc64d1f38 pc=0xf71966f2 >> > runtime.cgocallbackg(0x0) >> > /usr/local/go/src/runtime/cgocall.go:191 +0x9d fp=0xc64d1fe0 >> > sp=0xc64d1fb0 pc=0xf719650d >> > runtime.cgocallback_gofunc(0x0, 0x0, 0x0, 0x0) >> > /usr/local/go/src/runtime/asm_386.s:810 +0x79 fp=0xc64d1ff0 >> > sp=0xc64d1fe0 pc=0xf71eab79 >> > runtime.goexit() >> > /usr/local/go/src/runtime/asm_386.s:1325 +0x1 fp=0xc64d1ff4 >> > sp=0xc64d1ff0 pc=0xf71eb081 >> > Aborted >> > >> > >> > What is the error indicative of? >> > >> > Is invoking go plugin from go shared library supported? >> > >> > I know Go plugins have a few restrictions. I have verified that all the >> > above libraries are built on the same machine with the same gcc/go toolkit. >> >> I wouldn't be surprised if you are the first person to try this. I'm >> not surprised that it doesn't work. I can't think of any fundamental >> reason why it wouldn't work, so it may be relatively easy to fix if >> you want to dig into the linker. I'm not sure. >> >> Ian > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/82032f0b-5458-42a3-be21-81c00fd253a8%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAOyqgcV_xc-ESwDgkmXxL%2BV6cngN1EtLxVwX_m9d2k-MifXhgA%40mail.gmail.com.
