/*      $OpenBSD: boot.c,v 1.19 2022/01/08 06:49:41 guenther Exp $ */

/*
 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

/*
 * IMPORTANT: any functions below are NOT protected by SSP.  Please
 * do not add anything except what is required to reach GOT with
 * an adjustment.
 */

#define _DYN_LOADER

#include <sys/exec_elf.h>

#include "util.h"
#include "archdep.h"            /* for RELOC_TAG */

#include "../../lib/csu/os-note-elf.h"

#if RELOC_TAG == DT_RELA
typedef Elf_RelA        RELOC_TYPE;
# define RELOCATE_RELATIVE(w, r, b)     *(w) = (r)->r_addend + (b)
#elif RELOC_TAG == DT_REL
typedef Elf_Rel         RELOC_TYPE;
# define RELOCATE_RELATIVE(w, r, b)     *(w) += (b)
#else
# error "unknown RELOC_TAG"
#endif

/*
 * Local decls.
 */
void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot;

void
_dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp)
{
        AuxInfo         *auxstack;
        long            *stack;
        int             n, argc;
        char            **argv, **envp;
        long            loff;
        RELOC_TYPE      *dt_reloc;      /* DT_RELA   or DT_REL */
        Elf_Word        dt_relocsz;     /* DT_RELASZ or DT_RELSZ */
        RELOC_TYPE      *rend;

        /*
         * Scan argument and environment vectors. Find dynamic
         * data vector put after them.
         */
        stack = (long *)sp;
        argc = *stack++;
        argv = (char **)stack;
        envp = &argv[argc + 1];
        stack = (long *)envp;
        while (*stack++ != 0L)
                ;

        /*
         * Zero out dl_data.
         */
        for (n = 0; n <= AUX_entry; n++)
                dl_data[n] = 0;

        /*
         * Dig out auxiliary data set up by exec call. Move all known
         * tags to an indexed local table for easy access.
         */
        for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null;
            auxstack++) {
                if (auxstack->au_id > AUX_entry)
                        continue;
                dl_data[auxstack->au_id] = auxstack->au_v;
        }
        loff = dl_data[AUX_base];       /* XXX assumes ld.so is linked at 0x0 */

        /*
         * Scan the DYNAMIC section for the loader for the two items we need
         */
        dt_reloc = NULL;
        dt_relocsz = 0;
        while (dynp->d_tag != DT_NULL) {
                if (dynp->d_tag == RELOC_TAG)           /* DT_{RELA,REL} */
                        dt_reloc = (void *)(dynp->d_un.d_ptr + loff);
                else if (dynp->d_tag == RELOC_TAG+1)    /* DT_{RELA,REL}SZ */
                        dt_relocsz = dynp->d_un.d_val;
                dynp++;
        }

        rend = (RELOC_TYPE *)((char *)dt_reloc + dt_relocsz);
        for (; dt_reloc < rend; dt_reloc++) {
                Elf_Addr *ra;

                ra = (Elf_Addr *)(dt_reloc->r_offset + loff);
                RELOCATE_RELATIVE(ra, dt_reloc, loff);
        }
}