NetBSD/libexec/ld.elf_so/load.c
cgd 41fe218b25 First cut at an ELF shared loader. Originally from John Polstra's FreeBSD elf
kit, then hacked on by Matt Thomas <matt@3am-software.com>, then by me (to
make it work with new versions of the toolchain, etc.).  This runs, but it's
in serious need of cleaning and/or a fair bit of reworking.  See the README
file for more information, and a list of things to do.
1996-12-16 20:37:55 +00:00

142 lines
4.0 KiB
C

/* $NetBSD: load.c,v 1.1 1996/12/16 20:37:59 cgd 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"
/*
* Load a shared object into memory, if it is not already loaded. The
* argument must be a string allocated on the heap. This function assumes
* responsibility for freeing it when necessary.
*
* Returns a pointer to the Obj_Entry for the object. Returns NULL
* on failure.
*/
Obj_Entry *
_rtld_load_object(
char *filepath)
{
Obj_Entry *obj;
for (obj = _rtld_objlist->next; obj != NULL; obj = obj->next)
if (strcmp(obj->path, filepath) == 0)
break;
if (obj == NULL) { /* First use of this object, so we must map it in */
int fd;
if ((fd = open(filepath, O_RDONLY)) == -1) {
_rtld_error("Cannot open \"%s\"", filepath);
return NULL;
}
obj = _rtld_map_object(filepath, fd);
close(fd);
if (obj == NULL) {
free(filepath);
return NULL;
}
obj->path = filepath;
_rtld_digest_dynamic(obj);
*_rtld_objtail = obj;
_rtld_objtail = &obj->next;
#ifdef RTLD_LOADER
_rtld_linkmap_add(obj); /* for GDB */
#endif
dbg(" %p .. %p: %s", obj->mapbase,
obj->mapbase + obj->mapsize - 1, obj->path);
if (obj->textrel)
dbg(" WARNING: %s has impure text", obj->path);
} else
free(filepath);
++obj->refcount;
return obj;
}
/*
* Given a shared object, traverse its list of needed objects, and load
* each of them. Returns 0 on success. Generates an error message and
* returns -1 on failure.
*/
int
_rtld_load_needed_objects(
Obj_Entry *first)
{
Obj_Entry *obj;
int status = 0;
for (obj = first; obj != NULL; obj = obj->next) {
Needed_Entry *needed;
for (needed = obj->needed; needed != NULL; needed = needed->next) {
const char *name = obj->strtab + needed->name;
char *libpath = _rtld_find_library(name, obj);
if (libpath == NULL) {
status = -1;
} else {
needed->obj = _rtld_load_object(libpath);
if (needed->obj == NULL)
status = -1; /* FIXME - cleanup */
}
#ifdef RTLD_LOADER
if (status == -1)
return status;
#endif
}
}
return status;
}