NetBSD/libexec/ld.elf_so/headers.c

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1998-03-25 07:12:32 +03:00
/* $NetBSD: headers.c,v 1.2 1998/03/25 04:13:01 mhitch Exp $ */
/*
* Copyright 1996 John D. Polstra.
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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.
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <dirent.h>
#include "debug.h"
#include "rtld.h"
/*
* Process a shared object's DYNAMIC section, and save the important
* information in its Obj_Entry structure.
*/
void
_rtld_digest_dynamic(
Obj_Entry *obj)
{
Elf_Dyn *dynp;
Needed_Entry **needed_tail = &obj->needed;
const Elf_Dyn *dyn_rpath = NULL;
enum Elf_e_dynamic_type plttype = Elf_edt_rel;
Elf_Word relsize = 0, relasize = 0, pltrelsize = 0, pltrelasize = 0;
for (dynp = obj->dynamic; dynp->d_tag != Elf_edt_null; ++dynp) {
switch(dynp->d_tag) {
case Elf_edt_rel:
obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_relsz:
relsize = dynp->d_un.d_val;
break;
case Elf_edt_relent:
assert(dynp->d_un.d_val == sizeof(Elf_Rel));
break;
case Elf_edt_jmprel:
if (plttype == Elf_edt_rel) {
obj->pltrel = (const Elf_Rel *)
(obj->relocbase + dynp->d_un.d_ptr);
} else {
obj->pltrela = (const Elf_RelA *)
(obj->relocbase + dynp->d_un.d_ptr);
}
break;
case Elf_edt_pltrelsz:
if (plttype == Elf_edt_rel) {
pltrelsize = dynp->d_un.d_val;
} else {
pltrelasize = dynp->d_un.d_val;
}
break;
case Elf_edt_rela:
obj->rela = (const Elf_RelA *) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_relasz:
relasize = dynp->d_un.d_val;
break;
case Elf_edt_relaent:
assert(dynp->d_un.d_val == sizeof(Elf_RelA));
break;
case Elf_edt_pltrel:
plttype = dynp->d_un.d_val;
assert(plttype == Elf_edt_rel || plttype == Elf_edt_rela);
if (plttype == Elf_edt_rela) {
obj->pltrela = (const Elf_RelA *) obj->pltrel;
obj->pltrel = NULL;
pltrelasize = pltrelsize;
pltrelsize = 0;
}
break;
case Elf_edt_symtab:
obj->symtab = (const Elf_Sym *)
(obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_syment:
assert(dynp->d_un.d_val == sizeof(Elf_Sym));
break;
case Elf_edt_strtab:
obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_strsz:
obj->strsize = dynp->d_un.d_val;
break;
case Elf_edt_hash:
{
const Elf_Word *hashtab = (const Elf_Word *)
(obj->relocbase + dynp->d_un.d_ptr);
obj->nbuckets = hashtab[0];
obj->nchains = hashtab[1];
obj->buckets = hashtab + 2;
obj->chains = obj->buckets + obj->nbuckets;
}
break;
case Elf_edt_needed:
assert(!obj->rtld);
{
Needed_Entry *nep = NEW(Needed_Entry);
nep->name = dynp->d_un.d_val;
nep->obj = NULL;
nep->next = NULL;
*needed_tail = nep;
needed_tail = &nep->next;
}
break;
case Elf_edt_pltgot:
obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_textrel:
obj->textrel = true;
break;
case Elf_edt_symbolic:
obj->symbolic = true;
break;
case Elf_edt_rpath:
/*
* We have to wait until later to process this, because we
* might not have gotten the address of the string table yet.
*/
dyn_rpath = dynp;
break;
case Elf_edt_soname:
/* Not used by the dynamic linker. */
break;
case Elf_edt_init:
obj->init = (void (*)(void)) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_fini:
obj->fini = (void (*)(void)) (obj->relocbase + dynp->d_un.d_ptr);
break;
case Elf_edt_debug:
#ifdef RTLD_LOADER
dynp->d_un.d_ptr = (Elf_Addr) &_rtld_debug;
#endif
break;
1998-03-25 07:12:32 +03:00
#if defined(__mips__)
case DT_MIPS_LOCAL_GOTNO:
obj->local_gotno = dynp->d_un.d_val;
break;
case DT_MIPS_SYMTABNO:
obj->symtabno = dynp->d_un.d_val;
break;
case DT_MIPS_GOTSYM:
obj->gotsym = dynp->d_un.d_val;
break;
case DT_MIPS_RLD_MAP:
#ifdef RTLD_LOADER
*((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &_rtld_debug;
#endif
break;
#endif
}
}
obj->rellim = (const Elf_Rel *) ((caddr_t) obj->rel + relsize);
obj->relalim = (const Elf_RelA *) ((caddr_t) obj->rela + relasize);
obj->pltrellim = (const Elf_Rel *) ((caddr_t) obj->pltrel + pltrelsize);
obj->pltrelalim = (const Elf_RelA *) ((caddr_t) obj->pltrela + pltrelasize);
if (dyn_rpath != NULL) {
_rtld_add_paths(&obj->rpaths, obj->strtab + dyn_rpath->d_un.d_val);
}
}
/*
* Process a shared object's program header. This is used only for the
* main program, when the kernel has already loaded the main program
* into memory before calling the dynamic linker. It creates and
* returns an Obj_Entry structure.
*/
Obj_Entry *
_rtld_digest_phdr(
const Elf_Phdr *phdr,
int phnum,
caddr_t entry)
{
Obj_Entry *obj = CNEW(Obj_Entry);
const Elf_Phdr *phlimit = phdr + phnum;
const Elf_Phdr *ph;
int nsegs = 0;
for (ph = phdr; ph < phlimit; ++ph) {
switch(ph->p_type) {
case Elf_pt_phdr:
assert((const Elf_Phdr *) ph->p_vaddr == phdr);
obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
obj->phsize = ph->p_memsz;
break;
case Elf_pt_load:
assert(nsegs < 2);
if (nsegs == 0) { /* First load segment */
obj->vaddrbase = round_down(ph->p_vaddr);
obj->mapbase = (caddr_t) obj->vaddrbase;
obj->relocbase = obj->mapbase - obj->vaddrbase;
obj->textsize = round_up(ph->p_vaddr + ph->p_memsz) -
obj->vaddrbase;
} else { /* Last load segment */
obj->mapsize = round_up(ph->p_vaddr + ph->p_memsz) -
obj->vaddrbase;
}
++nsegs;
break;
case Elf_pt_dynamic:
obj->dynamic = (Elf_Dyn *) ph->p_vaddr;
break;
}
}
assert(nsegs == 2);
obj->entry = entry;
return obj;
}