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/* $OpenBSD: boot.c,v 1.5 2015/01/16 16:18:07 deraadt 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/types.h>
#include <sys/mman.h>
#include <sys/exec.h>
#include <sys/sysctl.h>
#include <nlist.h>
#include <link.h>
#include <dlfcn.h>
#include "syscall.h"
#include "archdep.h"
#include "path.h"
#include "resolve.h"
#include "sod.h"
#include "stdlib.h"
#include "dl_prebind.h"
#include "../../lib/csu/os-note-elf.h"
/*
* Local decls.
*/
void _dl_boot_bind(const long, long *, Elf_Dyn *);
void
_dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynamicp)
{
struct elf_object dynld; /* Resolver data for the loader */
AuxInfo *auxstack;
long *stack;
Elf_Dyn *dynp;
int n, argc;
char **argv, **envp;
long loff;
/*
* 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 */
/*
* We need to do 'selfreloc' in case the code weren't
* loaded at the address it was linked to.
*
* Scan the DYNAMIC section for the loader.
* Cache the data for easier access.
*/
#if defined(__alpha__)
dynp = (Elf_Dyn *)((long)_DYNAMIC);
#elif defined(__sparc__) || defined(__sparc64__) || defined(__powerpc__) || \
defined(__hppa__) || defined(__sh__)
dynp = dynamicp;
#else
dynp = (Elf_Dyn *)((long)_DYNAMIC + loff);
#endif
_dl_memset(dynld.Dyn.info, 0, sizeof(dynld.Dyn.info));
while (dynp != NULL && dynp->d_tag != DT_NULL) {
if (dynp->d_tag < DT_NUM)
dynld.Dyn.info[dynp->d_tag] = dynp->d_un.d_val;
else if (dynp->d_tag >= DT_LOPROC &&
dynp->d_tag < DT_LOPROC + DT_PROCNUM)
dynld.Dyn.info[dynp->d_tag - DT_LOPROC + DT_NUM] =
dynp->d_un.d_val;
if (dynp->d_tag == DT_TEXTREL)
dynld.dyn.textrel = 1;
dynp++;
}
/*
* Do the 'bootstrap relocation'. This is really only needed if
* the code was loaded at another location than it was linked to.
* We don't do undefined symbols resolving (to difficult..)
*/
/* "relocate" dyn.X values if they represent addresses */
{
int i, val;
/* must be code, not pic data */
int table[20];
i = 0;
table[i++] = DT_PLTGOT;
table[i++] = DT_HASH;
table[i++] = DT_STRTAB;
table[i++] = DT_SYMTAB;
table[i++] = DT_RELA;
table[i++] = DT_INIT;
table[i++] = DT_FINI;
table[i++] = DT_REL;
table[i++] = DT_JMPREL;
/* other processors insert their extras here */
table[i++] = DT_NULL;
for (i = 0; table[i] != DT_NULL; i++) {
val = table[i];
if (val >= DT_LOPROC && val < DT_LOPROC + DT_PROCNUM)
val = val - DT_LOPROC + DT_NUM;
else if (val >= DT_NUM)
continue;
if (dynld.Dyn.info[val] != 0)
dynld.Dyn.info[val] += loff;
}
}
{
u_int32_t rs;
Elf_Rel *rp;
int i;
rp = (Elf_Rel *)(dynld.Dyn.info[DT_REL]);
rs = dynld.dyn.relsz;
for (i = 0; i < rs; i += sizeof (Elf_Rel)) {
Elf_Addr *ra;
const Elf_Sym *sp;
sp = dynld.dyn.symtab;
sp += ELF_R_SYM(rp->r_info);
if (ELF_R_SYM(rp->r_info) && sp->st_value == 0) {
#if 0
/* cannot printf in this function */
_dl_wrstderr("Dynamic loader failure: self bootstrapping impossible.\n");
_dl_wrstderr("Undefined symbol: ");
_dl_wrstderr((char *)dynld.dyn.strtab +
sp->st_name);
#endif
_dl_exit(5);
}
ra = (Elf_Addr *)(rp->r_offset + loff);
RELOC_REL(rp, sp, ra, loff);
rp++;
}
}
for (n = 0; n < 2; n++) {
unsigned long rs;
Elf_RelA *rp;
int i;
switch (n) {
case 0:
rp = (Elf_RelA *)(dynld.Dyn.info[DT_JMPREL]);
rs = dynld.dyn.pltrelsz;
break;
case 1:
rp = (Elf_RelA *)(dynld.Dyn.info[DT_RELA]);
rs = dynld.dyn.relasz;
break;
default:
rp = NULL;
rs = 0;
}
for (i = 0; i < rs; i += sizeof (Elf_RelA)) {
Elf_Addr *ra;
const Elf_Sym *sp;
sp = dynld.dyn.symtab;
sp += ELF_R_SYM(rp->r_info);
if (ELF_R_SYM(rp->r_info) && sp->st_value == 0) {
#if 0
_dl_wrstderr("Dynamic loader failure: self bootstrapping impossible.\n");
_dl_wrstderr("Undefined symbol: ");
_dl_wrstderr((char *)dynld.dyn.strtab +
sp->st_name);
#endif
_dl_exit(6);
}
ra = (Elf_Addr *)(rp->r_offset + loff);
RELOC_RELA(rp, sp, ra, loff, dynld.dyn.pltgot);
rp++;
}
}
RELOC_GOT(&dynld, loff);
/*
* we have been fully relocated here, so most things no longer
* need the loff adjustment
*/
}
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