446 lines
11 KiB
C
446 lines
11 KiB
C
/*-
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* Copyright (c) 1997 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: link_aout.c,v 1.4 1997/11/07 08:52:59 phk Exp $
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/namei.h>
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#include <sys/fcntl.h>
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#include <sys/vnode.h>
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#include <sys/linker.h>
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#include <a.out.h>
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#include <link.h>
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static int link_aout_load_file(const char*, linker_file_t*);
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static int link_aout_lookup_symbol(linker_file_t, const char*,
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caddr_t*, size_t*);
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static void link_aout_unload(linker_file_t);
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/*
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* The file representing the currently running kernel. This contains
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* the global symbol table.
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*/
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static linker_file_t linker_kernel_file;
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static struct linker_class_ops link_aout_class_ops = {
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link_aout_load_file,
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};
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static struct linker_file_ops link_aout_file_ops = {
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link_aout_lookup_symbol,
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link_aout_unload,
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};
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typedef struct aout_file {
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char* address; /* Load address */
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struct _dynamic* dynamic; /* Symbol table etc. */
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} *aout_file_t;
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static int load_dependancies(linker_file_t lf);
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static int relocate_file(linker_file_t lf);
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/*
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* The kernel symbol table starts here.
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*/
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extern struct _dynamic _DYNAMIC;
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static void
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link_aout_init(void* arg)
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{
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struct _dynamic* dp = &_DYNAMIC;
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linker_add_class("a.out", NULL, &link_aout_class_ops);
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if (dp) {
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aout_file_t af;
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af = malloc(sizeof(struct aout_file), M_LINKER, M_NOWAIT);
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if (af == NULL)
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panic("link_aout_init: Can't create linker structures for kernel");
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af->address = 0;
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af->dynamic = dp;
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linker_kernel_file =
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linker_make_file(kernelname, af, &link_aout_file_ops);
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if (linker_kernel_file == NULL)
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panic("link_aout_init: Can't create linker structures for kernel");
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/*
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* XXX there must be a better way of getting these constants.
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*/
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linker_kernel_file->address = (caddr_t) 0xf0100000;
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linker_kernel_file->size = -0xf0100000;
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linker_current_file = linker_kernel_file;
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}
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}
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SYSINIT(link_aout, SI_SUB_KMEM, SI_ORDER_THIRD, link_aout_init, 0);
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static int
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link_aout_load_file(const char* filename, linker_file_t* result)
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{
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struct nameidata nd;
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struct proc* p = curproc; /* XXX */
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int error = 0;
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int resid;
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struct exec header;
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aout_file_t af;
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linker_file_t lf;
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
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error = vn_open(&nd, FREAD, 0);
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if (error)
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return error;
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/*
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* Read the a.out header from the file.
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*/
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error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) &header, sizeof header, 0,
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UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
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if (error)
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goto out;
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if (N_BADMAG(header) || !(N_GETFLAG(header) & EX_DYNAMIC))
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goto out;
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/*
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* We have an a.out file, so make some space to read it in.
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*/
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af = malloc(sizeof(struct aout_file), M_LINKER, M_WAITOK);
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af->address = malloc(header.a_text + header.a_data + header.a_bss,
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M_LINKER, M_WAITOK);
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/*
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* Read the text and data sections and zero the bss.
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*/
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error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) af->address,
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header.a_text + header.a_data, 0,
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UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
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if (error)
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goto out;
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bzero(af->address + header.a_text + header.a_data, header.a_bss);
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/*
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* Assume _DYNAMIC is the first data item.
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*/
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af->dynamic = (struct _dynamic*) (af->address + header.a_text);
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if (af->dynamic->d_version != LD_VERSION_BSD) {
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free(af->address, M_LINKER);
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free(af, M_LINKER);
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goto out;
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}
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(long) af->dynamic->d_un.d_sdt += af->address;
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lf = linker_make_file(filename, af, &link_aout_file_ops);
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if (lf == NULL) {
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free(af->address, M_LINKER);
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free(af, M_LINKER);
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error = ENOMEM;
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goto out;
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}
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lf->address = af->address;
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lf->size = header.a_text + header.a_data + header.a_bss;
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if ((error = load_dependancies(lf)) != 0
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|| (error = relocate_file(lf)) != 0) {
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linker_file_unload(lf);
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goto out;
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}
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*result = lf;
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out:
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VOP_UNLOCK(nd.ni_vp, 0, p);
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vn_close(nd.ni_vp, FREAD, p->p_ucred, p);
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return error;
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}
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static void
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link_aout_unload(linker_file_t file)
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{
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aout_file_t af = file->priv;
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if (af) {
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if (af->address)
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free(af->address, M_LINKER);
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free(af, M_LINKER);
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}
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}
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#define AOUT_RELOC(af, type, off) (type*) ((af)->address + (off))
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static int
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load_dependancies(linker_file_t lf)
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{
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aout_file_t af = lf->priv;
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linker_file_t lfdep;
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long off;
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struct sod* sodp;
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char* name;
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char* filename = 0;
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int error = 0;
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/*
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* All files are dependant on /kernel.
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*/
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linker_kernel_file->refs++;
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linker_file_add_dependancy(lf, linker_kernel_file);
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off = LD_NEED(af->dynamic);
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/*
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* Load the dependancies.
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*/
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while (off != 0) {
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sodp = AOUT_RELOC(af, struct sod, off);
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name = AOUT_RELOC(af, char, sodp->sod_name);
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/*
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* Prepend pathname if dep is not an absolute filename.
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*/
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if (name[0] != '/') {
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char* p;
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filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
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p = lf->filename + strlen(lf->filename) - 1;
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while (p >= lf->filename && *p != '/')
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p--;
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if (p >= lf->filename) {
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strncpy(filename, lf->filename, p - lf->filename);
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filename[p - lf->filename] = '\0';
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strcat(filename, "/");
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strcat(filename, name);
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name = filename;
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}
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}
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error = linker_load_file(name, &lfdep);
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if (error)
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goto out;
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error = linker_file_add_dependancy(lf, lfdep);
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if (error)
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goto out;
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off = sodp->sod_next;
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}
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out:
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if (filename)
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free(filename, M_TEMP);
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return error;
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}
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/*
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* XXX i386 dependant.
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*/
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static long
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read_relocation(struct relocation_info* r, char* addr)
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{
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int length = r->r_length;
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if (length == 0)
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return *(u_char*) addr;
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else if (length == 1)
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return *(u_short*) addr;
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else if (length == 2)
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return *(u_int*) addr;
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else
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printf("link_aout: unsupported relocation size %d\n", r->r_length);
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return 0;
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}
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static void
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write_relocation(struct relocation_info* r, char* addr, long value)
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{
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int length = r->r_length;
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if (length == 0)
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*(u_char*) addr = value;
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else if (length == 1)
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*(u_short*) addr = value;
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else if (length == 2)
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*(u_int*) addr = value;
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else
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printf("link_aout: unsupported relocation size %d\n", r->r_length);
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}
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static int
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relocate_file(linker_file_t lf)
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{
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aout_file_t af = lf->priv;
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struct relocation_info* rel;
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struct relocation_info* erel;
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struct relocation_info* r;
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struct nzlist* symbolbase;
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char* stringbase;
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struct nzlist* np;
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char* sym;
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long relocation;
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rel = AOUT_RELOC(af, struct relocation_info, LD_REL(af->dynamic));
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erel = AOUT_RELOC(af, struct relocation_info,
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LD_REL(af->dynamic) + LD_RELSZ(af->dynamic));
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symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
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stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
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for (r = rel; r < erel; r++) {
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char* addr;
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if (r->r_address == 0)
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break;
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addr = AOUT_RELOC(af, char, r->r_address);
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if (r->r_extern) {
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np = &symbolbase[r->r_symbolnum];
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sym = &stringbase[np->nz_strx];
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if (sym[0] != '_') {
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printf("link_aout: bad symbol name %s\n", sym);
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relocation = 0;
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} else
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relocation = (long)
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linker_file_lookup_symbol(lf, sym + 1,
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np->nz_type != (N_SETV+N_EXT));
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if (!relocation) {
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printf("link_aout: symbol %s not found\n", sym);
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return ENOENT;
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}
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relocation += read_relocation(r, addr);
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if (r->r_jmptable) {
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printf("link_aout: can't cope with jump table relocations\n");
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continue;
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}
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if (r->r_pcrel)
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relocation -= (long) af->address;
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if (r->r_copy) {
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printf("link_aout: can't cope with copy relocations\n");
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continue;
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}
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write_relocation(r, addr, relocation);
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} else {
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write_relocation(r, addr,
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(long)(read_relocation(r, addr) + af->address));
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}
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}
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return 0;
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}
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static long
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symbol_hash_value(aout_file_t af, const char* name)
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{
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long hashval;
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const char* p;
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hashval = '_'; /* fake a starting '_' for C symbols */
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for (p = name; *p; p++)
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hashval = (hashval << 1) + *p;
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return (hashval & 0x7fffffff) % LD_BUCKETS(af->dynamic);
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}
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int
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link_aout_lookup_symbol(linker_file_t file, const char* name,
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caddr_t* address, size_t* size)
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{
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aout_file_t af = file->priv;
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long hashval;
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struct rrs_hash* hashbase;
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struct nzlist* symbolbase;
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char* stringbase;
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struct rrs_hash* hp;
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struct nzlist* np;
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char* cp;
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if (LD_BUCKETS(af->dynamic) == 0)
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return NULL;
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hashbase = AOUT_RELOC(af, struct rrs_hash, LD_HASH(af->dynamic));
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symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
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stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
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restart:
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hashval = symbol_hash_value(af, name);
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hp = &hashbase[hashval];
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if (hp->rh_symbolnum == -1)
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return ENOENT;
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while (hp) {
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np = (struct nzlist *) &symbolbase[hp->rh_symbolnum];
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cp = stringbase + np->nz_strx;
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/*
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* Note: we fake the leading '_' for C symbols.
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*/
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if (cp[0] == '_' && !strcmp(cp + 1, name))
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break;
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if (hp->rh_next == 0)
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hp = NULL;
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else
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hp = &hashbase[hp->rh_next];
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}
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if (hp == NULL)
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/*
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* Not found.
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*/
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return ENOENT;
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/*
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* Check for an aliased symbol, whatever that is.
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*/
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if (np->nz_type == N_INDR+N_EXT) {
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name = stringbase + (++np)->nz_strx + 1; /* +1 for '_' */
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goto restart;
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}
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/*
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* Check this is an actual definition of the symbol.
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*/
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if (np->nz_value == 0)
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return ENOENT;
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if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
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if (np->nz_other == AUX_FUNC)
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/* weak function */
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return ENOENT;
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*address = 0;
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*size = np->nz_value;
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} else {
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*address = AOUT_RELOC(af, char, np->nz_value);
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*size = np->nz_size;
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}
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return 0;
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}
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