graphene/Pal/src/do-rel.h

/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */

/* Copyright (C) 2014 OSCAR lab, Stony Brook University
   This file is part of Graphene Library OS.

   Graphene Library OS is free software: you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation, either version 3 of the
   License, or (at your option) any later version.

   Graphene Library OS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/*
 * do-rel.h
 *
 * This files contain architecture-independent macros of ELF dynamic
 * relocation function.
 * The source code is imported and modified from the GNU C Library.
 */

#include <pal_rtld.h>

#include "dl-machine-x86_64.h"

#define elf_dynamic_do_rel          elf_dynamic_do_rela
#define RELCOUNT_IDX                VERSYMIDX (DT_RELACOUNT)
#define Rel                         Rela
#define elf_machine_rel             elf_machine_rela
#define elf_machine_rel_relative    elf_machine_rela_relative

#ifndef DO_ELF_MACHINE_REL_RELATIVE
# define DO_ELF_MACHINE_REL_RELATIVE(l_addr, relative)     \
    elf_machine_rel_relative (l_addr, relative,            \
                              (void *) (l_addr + relative->r_offset))
#endif

static void __attribute__((unused))
elf_dynamic_do_rel (ElfW(Dyn) **l_info, ElfW(Addr) l_addr,
                    ElfW(Addr) reladdr, ElfW(Addr) relsize,
                    bool do_rel, bool do_rel_relative)
{
    ElfW(Rel) *r = (void *) reladdr;
    ElfW(Rel) *end = (void *) (reladdr + relsize);

    if (!l_info[DT_SYMTAB])
        return;

    {
        ElfW(Sym) *symtab = (void *) D_PTR (l_info[DT_SYMTAB]);
        ElfW(Word) nrelative = (l_info[RELCOUNT_IDX] == NULL
                                ? 0 : l_info[RELCOUNT_IDX]->d_un.d_val);
        ElfW(Rel) *relative = r;
        r = r + MIN (nrelative, relsize / sizeof (ElfW(Rel)));

        if (do_rel_relative)
#ifndef RTLD_BOOTSTRAP
            /* This is defined in rtld.c, but nowhere in the static libc.a; make
               the reference weak so static programs can still link.  This
               declaration cannot be done when compiling rtld.c (i.e. #ifdef
               RTLD_BOOTSTRAP) because rtld.c contains the common defn for
               _dl_rtld_map, which is incompatible with a weak decl in the same
               file.  */
# if !defined DO_RELA || defined ELF_MACHINE_REL_RELATIVE
            /* Rela platforms get the offset from r_addend and this must
               be copied in the relocation address.  Therefore we can skip
               the relative relocations only if this is for rel
               relocations or rela relocations if they are computed as
               memory_loc += l_addr...  */
            if (l_addr != 0)
# else
            /* ...or we know the object has been prelinked.  */
            if (l_addr != 0 || !l_info[VALIDX(DT_GNU_PRELINKED)])
# endif
#endif
                for (; relative < r; ++relative)
                    DO_ELF_MACHINE_REL_RELATIVE (l_addr, relative);

        for (; r < end; ++r)
            elf_machine_rel (l_info, l_addr, r,
                             &symtab[ELFW(R_SYM) (r->r_info)],
                             (void *) (l_addr + r->r_offset),
                             do_rel, do_rel_relative);
    }
}

#undef elf_dynamic_do_rel
#undef Rel
#undef elf_machine_rel
#undef elf_machine_rel_relative
#undef DO_ELF_MACHINE_REL_RELATIVE
#undef RELCOUNT_IDX