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/* $OpenBSD: resolve.c,v 1.16 2003/01/30 03:46:46 drahn 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed under OpenBSD by
* Per Fogelstrom, Opsycon AB, Sweden.
* 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.
*
*/
#define _DYN_LOADER
#include <sys/types.h>
#include <nlist.h>
#include <link.h>
#include "syscall.h"
#include "archdep.h"
#include "resolve.h"
elf_object_t *_dl_objects;
elf_object_t *_dl_last_object;
/*
* Initialize and add a new dynamic object to the object list.
* Perform necessary relocations of pointers.
*/
elf_object_t *
_dl_add_object(const char *objname, Elf_Dyn *dynp, const u_long *dl_data,
const int objtype, const long laddr, const long loff)
{
elf_object_t *object;
#if 0
_dl_printf("objname [%s], dynp %p, dl_data %p, objtype %x laddr %lx, loff %lx\n",
objname, dynp, dl_data, objtype, laddr, loff);
#endif
object = _dl_malloc(sizeof(elf_object_t));
object->next = NULL;
if (_dl_objects == 0) { /* First object ? */
_dl_last_object = _dl_objects = object;
} else {
_dl_last_object->next = object;
object->prev = _dl_last_object;
_dl_last_object = object;
}
object->load_dyn = dynp;
while (dynp->d_tag != DT_NULL) {
if (dynp->d_tag < DT_NUM)
object->Dyn.info[dynp->d_tag] = dynp->d_un.d_val;
else if (dynp->d_tag >= DT_LOPROC &&
dynp->d_tag < DT_LOPROC + DT_NUM)
object->Dyn.info[dynp->d_tag + DT_NUM - DT_LOPROC] =
dynp->d_un.d_val;
if (dynp->d_tag == DT_TEXTREL)
object->dyn.textrel = 1;
if (dynp->d_tag == DT_SYMBOLIC)
object->dyn.symbolic = 1;
if (dynp->d_tag == DT_BIND_NOW)
object->dyn.bind_now = 1;
dynp++;
}
/*
* Now relocate all pointer to dynamic info, but only
* the ones which have pointer values.
*/
if (object->Dyn.info[DT_PLTGOT])
object->Dyn.info[DT_PLTGOT] += loff;
if (object->Dyn.info[DT_HASH])
object->Dyn.info[DT_HASH] += loff;
if (object->Dyn.info[DT_STRTAB])
object->Dyn.info[DT_STRTAB] += loff;
if (object->Dyn.info[DT_SYMTAB])
object->Dyn.info[DT_SYMTAB] += loff;
if (object->Dyn.info[DT_RELA])
object->Dyn.info[DT_RELA] += loff;
if (object->Dyn.info[DT_SONAME])
object->Dyn.info[DT_SONAME] += loff;
if (object->Dyn.info[DT_RPATH])
object->Dyn.info[DT_RPATH] += object->Dyn.info[DT_STRTAB];
if (object->Dyn.info[DT_REL])
object->Dyn.info[DT_REL] += loff;
if (object->Dyn.info[DT_INIT])
object->Dyn.info[DT_INIT] += loff;
if (object->Dyn.info[DT_FINI])
object->Dyn.info[DT_FINI] += loff;
if (object->Dyn.info[DT_JMPREL])
object->Dyn.info[DT_JMPREL] += loff;
if (object->Dyn.info[DT_HASH] != 0) {
Elf_Word *hashtab = (Elf_Word *)object->Dyn.info[DT_HASH];
object->nbuckets = hashtab[0];
object->nchains = hashtab[1];
object->buckets = hashtab + 2;
object->chains = object->buckets + object->nbuckets;
}
if (dl_data) {
object->phdrp = (Elf_Phdr *) dl_data[AUX_phdr];
object->phdrc = dl_data[AUX_phnum];
}
object->obj_type = objtype;
object->load_addr = laddr;
object->load_offs = loff;
object->load_name = _dl_strdup(objname);
object->refcount = 1;
object->first_child = NULL;
object->last_child = NULL;
return(object);
}
void
_dl_remove_object(elf_object_t *object)
{
elf_object_t *depobj;
object->prev->next = object->next;
if (object->next)
object->next->prev = object->prev;
if (_dl_last_object == object)
_dl_last_object = object->prev;
if (object->load_name)
_dl_free(object->load_name);
while ((depobj = object->dep_next)) {
object->dep_next = object->dep_next->dep_next;
_dl_free(depobj);
}
_dl_free(object);
}
elf_object_t *
_dl_lookup_object(const char *name)
{
elf_object_t *object;
object = _dl_objects;
while (object) {
if (_dl_strcmp(name, object->load_name) == 0)
return(object);
object = object->next;
}
return(0);
}
Elf_Addr
_dl_find_symbol(const char *name, elf_object_t *startlook,
const Elf_Sym **ref, int flags, int req_size, const char *module_name)
{
const Elf_Sym *weak_sym = NULL;
const char *weak_symn = NULL; /* remove warning */
Elf_Addr weak_offs = 0;
unsigned long h = 0;
const char *p = name;
elf_object_t *object, *weak_object = NULL;
while (*p) {
unsigned long g;
h = (h << 4) + *p++;
if ((g = h & 0xf0000000))
h ^= g >> 24;
h &= ~g;
}
for (object = startlook;
object;
object = ((flags & SYM_SEARCH_SELF) ? 0 : object->next)) {
const Elf_Sym *symt = object->dyn.symtab;
const char *strt = object->dyn.strtab;
long si;
const char *symn;
for (si = object->buckets[h % object->nbuckets];
si != STN_UNDEF; si = object->chains[si]) {
const Elf_Sym *sym = symt + si;
if (sym->st_value == 0)
continue;
if (ELF_ST_TYPE(sym->st_info) != STT_NOTYPE &&
ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
ELF_ST_TYPE(sym->st_info) != STT_FUNC)
continue;
symn = strt + sym->st_name;
if (sym != *ref &&
_dl_strcmp(symn, name))
continue;
/* allow this symbol if we are referring to a function
* which has a value, even if section is UNDEF.
* this allows &func to refer to PLT as per the
* ELF spec. st_value is checked above.
* if flags has SYM_PLT set, we must have actual
* symbol, so this symbol is skipped.
*/
if (sym->st_shndx == SHN_UNDEF) {
if ((flags & SYM_PLT) || sym->st_value == 0 ||
ELF_ST_TYPE(sym->st_info) != STT_FUNC) {
continue;
}
}
if (ELF_ST_BIND(sym->st_info) == STB_GLOBAL) {
*ref = sym;
if (req_size != sym->st_size &&
req_size != 0 &&
(ELF_ST_TYPE(sym->st_info) != STT_FUNC)) {
_dl_printf("%s: %s : WARNING: "
"symbol(%s) size mismatch ",
_dl_progname, object->load_name,
symn);
_dl_printf("relink your program\n");
}
return(object->load_offs);
} else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
if (!weak_sym) {
weak_sym = sym;
weak_symn = symn;
weak_offs = object->load_offs;
weak_object = object;
}
}
}
}
if (flags & SYM_WARNNOTFOUND && weak_sym == NULL) {
_dl_printf("%s:%s: undefined symbol '%s'\n",
_dl_progname, module_name, name);
}
*ref = weak_sym;
if (weak_sym != NULL && req_size != weak_sym->st_size &&
req_size != 0 && (ELF_ST_TYPE(weak_sym->st_info) != STT_FUNC)) {
_dl_printf("%s:%s: %s : WARNING: "
"symbol(%s) size mismatch ",
_dl_progname, module_name, weak_object->load_name,
weak_symn);
_dl_printf("relink your program\n");
}
return(weak_offs);
}
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