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Hi,

this is on NetBSD-current/i386, from Oct 2, 1999.

When using dlsym() to find a symbol in an object loaded by dlopen(),
the chain of all loaded objects is checked for the symbol instead
of the object passed to dlsym(). IMHO, this is broken. The module
passed to dlsym() should be checked first.

Attached you find a project that loads dynamic modules using dlopen().
All of those modules have an "info()" function that needs to be
called. The trouble is, with the current ld.so implementation the
info() function of the first dynamically loaded module is always
returned by dlsym().

A workaround is to use the -Bsymbolic linker flag, but this can't be
the right solution???

The following patch would fix the problem from my perspective, but
probably breaks lots of other things?

cvs diff: Diffing /usr/src/libexec/ld.elf_so/
Index: /usr/src/libexec/ld.elf_so//symbol.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /home/cvs/netbsd/src/libexec/ld.elf_so/symbol.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 symbol.c
--- symbol.c	1999/06/14 20:19:21	1.1.1.1
+++ symbol.c	1999/10/13 14:58:40
@@ -143,7 +143,7 @@
 	}
 	hash =3D _rtld_elf_hash(name);
=20
-	if (refobj->symbolic) {	/* Look first in the referencing object */
+	if (1) {	/* Look first in the referencing object */
 		const Elf_Sym *def;
=20
 		def =3D _rtld_symlook_obj(name, hash, refobj, in_plt);


cu Jo

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PROG =		ldsotest
CLEANFILES +=	m1.so m2.so
DPADD +=	m1.so m2.so

.ifdef WORKS
SYMBOLIC =	-Wl,-Bsymbolic
.endif

.SUFFIXES: .so

.c.so:
	$(CC) $(SYMBOLIC) -shared -o ${.TARGET} ${.IMPSRC}

.include <bsd.prog.mk>

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#include <dlfcn.h>
#include <stdio.h>

static void modinfo(const char *);

int
main(void)
{
	modinfo("./m1.so");
	modinfo("./m2.so");

	return 0;
}

void
modinfo(const char *name)
{
	void *h;
	void (*info)(void);

	if ((h = dlopen(name, DL_LAZY)) == NULL) {
		fprintf(stderr, "%s: %s\n", name, dlerror());
		return;
	}

	if ((info = dlsym(h, "info")) != NULL)
		info();
	else
		fprintf(stderr, "%s: %s\n", name, dlerror());
}

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#include <stdio.h>

void
info(void)
{
	printf("m1\n");
}

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#include <stdio.h>

void
info(void)
{
	printf("m2\n");
}

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