Support for relocation type 10 in ld.elf_so

[Allen Briggs <briggs%wasabisystems.com@localhost>]

I was looking at PR pkg/13771 which complains that Apache's mod_perl is
not usable because:

# apachectl configtest
Syntax error on line 1220 of /usr/pkg/etc/httpd/httpd.conf:
Cannot load /usr/pkg/lib/httpd/mod_perl.so into server: 
/usr/pkg/lib/httpd/mod_perl.so: Unsupported relocation type 10 in non-PLT 
relocations

I'm not sure how we're getting the R_PPC_REL24 relocations in
mod_perl.so, but that's really kind of unacceptable behavior.
Todd V. mentioned that, well, ld.elf_so could always be taught
about this relocation type, and I think the following patch
does this.

This allows apache+mod_perl to start and use a simple perl script.  I
don't know if the relocation is 100% correct or not, though, and I'm
not sure the best way to test.

Comments?

========================================================================
Index: reloc.c
===================================================================
RCS file: /cvsroot/basesrc/libexec/ld.elf_so/reloc.c,v
retrieving revision 1.51
diff -u -r1.51 reloc.c
--- reloc.c     2002/02/03 23:34:42     1.51
+++ reloc.c     2002/06/16 03:22:25
@@ -507,6 +507,40 @@
                rdbg(dodebug, ("16_HA in %s --> %p", obj->path,
                    (void *)*where));
                break;
+
+       case R_TYPE(REL24): {   /* S + A - P >> 2 */
+                Elf32_Sword addend;
+                
+                /*      
+                 * Extract addend and sign-extend if needed.
+                 */ 
+                addend = *where & 0x03fffffc;
+                if (addend & 0x04000000)
+                        addend |= 0xfc000000; 
+
+               def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
+                   &defobj, false);
+               if (def == NULL)
+                       return -1;
+
+               tmp = (Elf_Addr)obj->relocbase + def->st_value + addend
+                   - (Elf_Addr)where;
+               if ((tmp & 0xfc000000) != 0xfc000000 &&
+                   (tmp & 0xfc000000) != 0) {
+                       _rtld_error(
+                       "%s: R_PPC_REL24 relocation @ %p to %s failed "
+                       "(displacement %ld (%#lx) out of range)",
+                           obj->path, where, defobj->strtab + def->st_name,
+                           (long) tmp, (long) tmp);
+                       return -1;
+               }
+
+               *where = (*where & 0xfc000003) | (tmp & 0x03fffffc);
+               rdbg(dodebug, ("REL24 %s in %s --> %p @ %p in %s",
+                   defobj->strtab + def->st_name, obj->path,
+                   (void *)*where, where, defobj->path));
+               }
+               break;
 #endif /* __powerpc__ */
 
 #if defined(__arm__)
========================================================================

-allen

-- 
 Allen Briggs                     briggs%wasabisystems.com@localhost
 http://www.wasabisystems.com/    Quality NetBSD CDs, Sales, Support, Service
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