/*      $OpenBSD: boot_md.c,v 1.6 2022/01/31 05:43:22 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"

typedef Elf_RelA        RELOC_TYPE;

/*
 * 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;
        const RELOC_TYPE        *rend;
        const RELOC_TYPE        *dt_reloc;      /* DT_RELA */
        Elf_Addr                dt_relocsz;     /* DT_RELASZ */
        Elf_Addr                dt_pltgot;
        Elf_Addr                dt_pltrelsz;
        const Elf_Sym           *dt_symtab;
        const RELOC_TYPE        *dt_jmprel;

        /*
         * 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_pltrelsz = dt_relocsz = dt_pltgot = 0;
        dt_jmprel = dt_reloc = NULL;
        dt_symtab = NULL;
        while (dynp->d_tag != DT_NULL) {
                /* first the tags that are pointers to be relocated */
                if (dynp->d_tag == DT_PLTGOT)
                        dt_pltgot = dynp->d_un.d_ptr + loff;
                else if (dynp->d_tag == DT_SYMTAB)
                        dt_symtab = (void *)(dynp->d_un.d_ptr + loff);
                else if (dynp->d_tag == RELOC_TAG)      /* DT_{RELA,REL} */
                        dt_reloc = (void *)(dynp->d_un.d_ptr + loff);
                else if (dynp->d_tag == DT_JMPREL)
                        dt_jmprel = (void *)(dynp->d_un.d_ptr + loff);

                /* Now for the tags that are just sizes or counts */
                else if (dynp->d_tag == DT_PLTRELSZ)
                        dt_pltrelsz = dynp->d_un.d_val;
                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_jmprel + dt_pltrelsz);
        for (; dt_jmprel < rend; dt_jmprel++) {
                Elf_Addr *ra;
                const Elf_Sym *sp;

                sp = dt_symtab + ELF_R_SYM(dt_jmprel->r_info);
                ra = (Elf_Addr *)(dt_jmprel->r_offset + loff);
                ra[0] = loff + sp->st_value + dt_jmprel->r_addend;
                ra[1] = dt_pltgot;
        }

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

                sp = dt_symtab + ELF_R_SYM(dt_reloc->r_info);
                ra = (Elf_Addr *)(dt_reloc->r_offset + loff);
                *ra = loff + sp->st_value + dt_reloc->r_addend;
        }
}