File: [local] / src / libexec / ld.so / dlfcn.c (download)
Revision 1.2, Sun Sep 17 17:50:57 2000 UTC (23 years, 8 months ago) by deraadt
Branch: MAIN
CVS Tags: OPENBSD_2_8_BASE, OPENBSD_2_8 Changes since 1.1: +17 -8 lines
activate ldd, and indent some ld.so messages to make it easier to see what is going on
|
/* $OpenBSD: dlfcn.c,v 1.2 2000/09/17 17:50:57 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.
* 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 <dlfcn.h>
#include "syscall.h"
#include "archdep.h"
#include "resolve.h"
int _dl_errno;
void _dl_show_objects(void);
static int _dl_real_close(void *handle);
static void _dl_unload_deps(elf_object_t *object);
extern char *_dl_debug;
void *
dlopen(const char *libname, int how)
{
elf_object_t *object;
elf_object_t *dynobj;
Elf32_Dyn *dynp;
if (_dl_debug) {
_dl_printf("loading: %s\n", libname);
}
object = _dl_load_shlib(libname, _dl_objects, OBJTYPE_DLO);
if(object == 0) {
return((void *)0);
}
if(object->refcount > 1) {
return((void *)object); /* Already loaded */
}
/*
* Check for 'needed' objects. For each 'needed' object we
* create a 'shadow' object and add it to a list attached to
* the object so we know our dependencies. This list should
* also be used to determine the library search order when
* resolving undefined symbols. This is not yet done. XXX
*/
dynobj = object;
while(dynobj) {
elf_object_t *tmpobj = dynobj;
for(dynp = dynobj->load_dyn; dynp->d_tag; dynp++) {
const char *libname;
elf_object_t *depobj;
if(dynp->d_tag != DT_NEEDED) {
continue;
}
libname = dynobj->dyn.strtab + dynp->d_un.d_val;
depobj = _dl_load_shlib(libname, dynobj, OBJTYPE_DLO);
if(!depobj) {
_dl_exit(4);
}
tmpobj->dep_next = _dl_malloc(sizeof(elf_object_t));
tmpobj->dep_next->next = depobj;
tmpobj = tmpobj->dep_next;
}
dynobj = dynobj->next;
}
_dl_rtld(object);
_dl_call_init(object);
#ifdef __mips__
if(_dl_debug_map->r_brk) {
_dl_debug_map->r_state = RT_ADD;
(*((void (*)())_dl_debug_map->r_brk))();
_dl_debug_map->r_state = RT_CONSISTENT;
(*((void (*)())_dl_debug_map->r_brk))();
}
#endif /* __mips__ */
return((void *)object);
}
void *
dlsym(void *handle, const char *name)
{
elf_object_t *object;
elf_object_t *dynobj;
void *retval;
const Elf32_Sym *sym = 0;
object = (elf_object_t *)handle;
dynobj = _dl_objects;
while(dynobj && dynobj != object) {
dynobj = dynobj->next;
}
if(!dynobj || object != dynobj) {
_dl_errno = DL_INVALID_HANDLE;
return(0);
}
retval = (void *)_dl_find_symbol(name, object, &sym, 1, 1);
if(retval) {
retval += sym->st_value;
}
else {
_dl_errno = DL_NO_SYMBOL;
}
return(retval);
}
int
dlctl(void *handle, int command, void *data)
{
switch(command) {
#ifdef __mips__
case DL_DUMP_MAP:
_dl_show_objects();
return(0);
#endif /* __mips__ */
default:
_dl_errno = DL_INVALID_CTL;
break;
}
return(-1);
}
int
dlclose(void *handle)
{
int retval;
retval = _dl_real_close(handle);
#ifdef __mips__
if(_dl_debug_map->r_brk) {
_dl_debug_map->r_state = RT_DELETE;
(*((void (*)())_dl_debug_map->r_brk))();
_dl_debug_map->r_state = RT_CONSISTENT;
(*((void (*)())_dl_debug_map->r_brk))();
}
#endif /* __mips__ */
return(retval);
}
static int
_dl_real_close(void *handle)
{
elf_object_t *object;
elf_object_t *dynobj;
object = (elf_object_t *)handle;
dynobj = _dl_objects;
while(dynobj && dynobj != object) {
dynobj = dynobj->next;
}
if(!dynobj || object != dynobj) {
_dl_errno = DL_INVALID_HANDLE;
return(1);
}
if(object->refcount == 1) {
if(dynobj->dep_next) {
_dl_unload_deps(dynobj);
}
}
_dl_unload_shlib(object);
return(0);
}
/*
* Scan through the shadow dep list and 'unload' every library
* we depend upon. Shadow objects are removed when removing ourself.
*/
static void
_dl_unload_deps(elf_object_t *object)
{
elf_object_t *depobj;
depobj = object->dep_next;
while(depobj) {
if(depobj->next->refcount == 1) { /* This object will go away */
if(depobj->next->dep_next) {
_dl_unload_deps(depobj->next);
}
_dl_unload_shlib(depobj->next);
}
depobj = depobj->dep_next;
}
}
/*
* dlerror()
*
* Return a character string describing the last dl... error occured.
*/
const char *
dlerror()
{
switch(_dl_errno) {
case DL_NOT_FOUND:
return("File not found");
case DL_CANT_OPEN:
return("Can't open file");
case DL_NOT_ELF:
return("File not an ELF object");
case DL_CANT_OPEN_REF:
return("Can't open referenced object");
case DL_CANT_MMAP:
return("Can't map ELF object");
case DL_INVALID_HANDLE:
return("Invalid handle");
case DL_NO_SYMBOL:
return("Unable to resolve symbol");
case DL_INVALID_CTL:
return("Invalid dlctl() command");
default:
return("Unknown error");
}
}
void
_dl_show_objects()
{
elf_object_t *object;
static char *otyp[] = {
"none", "rtld", "exe ", "rlib", "dlib"
};
object = _dl_objects;
_dl_printf("\tStart End Type Ref Name\n");
while(object) {
_dl_printf("\t%X %X %s %d %s\n", object->load_addr,
object->load_size, otyp[object->obj_type],
object->refcount, object->load_name);
object = object->next;
}
}