Re: 11.0_BETA: glxinfo crashes with Segmentation fault

[RVP <rvp%SDF.ORG@localhost>]

On Sat, 20 Dec 2025, RVP wrote:

> Shared libs. should use __cxa_atexit() with a non-NULL `dso' parameter.

This works on FreeBSD, OpenBSD, Linux and even OpenIndiana. (Anything which
supports C++ would be my bet.)

-RVP

---START---
==> dl-atexit.c <==
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>

static void
diemain(void)
{
	printf("%s: atexit handler\n", __func__);
}

int
main(void)
{
	extern const void* const __dso_handle;
	printf("__dso_handle = %p\n", __dso_handle);

	atexit(diemain);

	void *h = dlopen("libfoo.so", RTLD_LOCAL | RTLD_LAZY);
	if (h == NULL) {
		fprintf(stderr, "dlopen(): %s\n", dlerror());
		return 1;
	}
	void (*foo)(void) = dlsym(h, "foo");
	if (foo == NULL) {
		fprintf(stderr, "dlsym(foo): %s\n", dlerror());
		return 1;
	}
	printf("%s: calling foo()\n", __func__);
	foo();
	printf("%s: calling dlclose()\n", __func__);
	dlclose(h);
	printf("%s: exiting...\n", __func__);
	return 0;
}

==> libfoo.c <==
#include <stdio.h>
#include <stdlib.h>

extern int __cxa_atexit(void (*)(void*), void*, const void*);
extern const void* const __dso_handle;

static void
// die(void)
die(void* v)
{
	printf("%s: atexit handler\n", __func__);
}

void
foo(void)
{
	printf("__dso_handle = %p\n", __dso_handle);
	// atexit(die);
	__cxa_atexit(die, NULL, __dso_handle);
	printf("%s: atexit handler die() @ %p\n", __func__, die);
}

==> Makefile <==
LDFLAGS= -fuse-linker-plugin -Wl,--enable-new-dtags,-z,relro,-z,now

dl-atexit: dl-atexit.c libfoo.so
	cc -pie -fPIE -o dl-atexit dl-atexit.c -Wl,-rpath=$$(pwd) ${LDFLAGS}

libfoo.so: libfoo.c
	cc -shared -DPIC -fPIC -o libfoo.so libfoo.c ${LDFLAGS}

run: dl-atexit
	./dl-atexit

clean:
	rm -f dl-atexit *.so *.core
---END---