305 lines
7.4 KiB
C
305 lines
7.4 KiB
C
/* $NetBSD: headers.c,v 1.6 1999/11/07 00:21:12 mycroft Exp $ */
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/*
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* Copyright 1996 John D. Polstra.
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* Copyright 1996 Matt Thomas <matt@3am-software.com>
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Polstra.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Dynamic linker for ELF.
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*
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* John Polstra <jdp@polstra.com>.
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*/
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <dirent.h>
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#include "debug.h"
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#include "rtld.h"
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/*
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* Process a shared object's DYNAMIC section, and save the important
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* information in its Obj_Entry structure.
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*/
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void
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_rtld_digest_dynamic(obj)
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Obj_Entry *obj;
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{
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Elf_Dyn *dynp;
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Needed_Entry **needed_tail = &obj->needed;
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const Elf_Dyn *dyn_rpath = NULL;
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Elf_Sword plttype = DT_REL;
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Elf_Word relsz = 0, relasz = 0;
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Elf_Word pltrelsz = 0, pltrelasz = 0;
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for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; ++dynp) {
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switch (dynp->d_tag) {
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case DT_REL:
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obj->rel = (const Elf_Rel *)
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_RELSZ:
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relsz = dynp->d_un.d_val;
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break;
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case DT_RELENT:
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assert(dynp->d_un.d_val == sizeof(Elf_Rel));
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break;
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case DT_JMPREL:
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if (plttype == DT_REL) {
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obj->pltrel = (const Elf_Rel *)
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(obj->relocbase + dynp->d_un.d_ptr);
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} else {
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obj->pltrela = (const Elf_RelA *)
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(obj->relocbase + dynp->d_un.d_ptr);
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}
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break;
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case DT_PLTRELSZ:
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if (plttype == DT_REL) {
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pltrelsz = dynp->d_un.d_val;
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} else {
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pltrelasz = dynp->d_un.d_val;
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}
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break;
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case DT_RELA:
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obj->rela = (const Elf_RelA *)
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_RELASZ:
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relasz = dynp->d_un.d_val;
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break;
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case DT_RELAENT:
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assert(dynp->d_un.d_val == sizeof(Elf_RelA));
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break;
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case DT_PLTREL:
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plttype = dynp->d_un.d_val;
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assert(plttype == DT_REL ||
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plttype == DT_RELA);
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if (plttype == DT_RELA) {
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obj->pltrela = (const Elf_RelA *) obj->pltrel;
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obj->pltrel = NULL;
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pltrelasz = pltrelsz;
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pltrelsz = 0;
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}
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break;
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case DT_SYMTAB:
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obj->symtab = (const Elf_Sym *)
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_SYMENT:
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assert(dynp->d_un.d_val == sizeof(Elf_Sym));
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break;
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case DT_STRTAB:
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obj->strtab = (const char *)
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_STRSZ:
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obj->strsize = dynp->d_un.d_val;
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break;
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case DT_HASH:
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{
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const Elf_Word *hashtab = (const Elf_Word *)
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(obj->relocbase + dynp->d_un.d_ptr);
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obj->nbuckets = hashtab[0];
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obj->nchains = hashtab[1];
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obj->buckets = hashtab + 2;
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obj->chains = obj->buckets + obj->nbuckets;
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}
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break;
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case DT_NEEDED:
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assert(!obj->rtld);
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{
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Needed_Entry *nep = NEW(Needed_Entry);
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nep->name = dynp->d_un.d_val;
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nep->obj = NULL;
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nep->next = NULL;
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*needed_tail = nep;
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needed_tail = &nep->next;
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}
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break;
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case DT_PLTGOT:
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obj->pltgot = (Elf_Addr *)
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_TEXTREL:
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obj->textrel = true;
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break;
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case DT_SYMBOLIC:
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obj->symbolic = true;
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break;
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case DT_RPATH:
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/*
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* We have to wait until later to process this, because
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* we might not have gotten the address of the string
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* table yet.
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*/
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dyn_rpath = dynp;
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break;
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case DT_SONAME:
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/* Not used by the dynamic linker. */
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break;
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case DT_INIT:
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obj->init = (void (*) __P((void)))
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_FINI:
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obj->fini = (void (*) __P((void)))
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(obj->relocbase + dynp->d_un.d_ptr);
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break;
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case DT_DEBUG:
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#ifdef RTLD_LOADER
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dynp->d_un.d_ptr = (Elf_Addr)&_rtld_debug;
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#endif
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break;
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#if defined(__mips__)
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case DT_MIPS_LOCAL_GOTNO:
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obj->local_gotno = dynp->d_un.d_val;
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break;
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case DT_MIPS_SYMTABNO:
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obj->symtabno = dynp->d_un.d_val;
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break;
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case DT_MIPS_GOTSYM:
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obj->gotsym = dynp->d_un.d_val;
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break;
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case DT_MIPS_RLD_MAP:
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#ifdef RTLD_LOADER
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*((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr)
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&_rtld_debug;
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#endif
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break;
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#endif
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}
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}
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obj->rellim = (const Elf_Rel *)((caddr_t)obj->rel + relsz);
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obj->relalim = (const Elf_RelA *)((caddr_t)obj->rela + relasz);
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obj->pltrellim = (const Elf_Rel *)((caddr_t)obj->pltrel + pltrelsz);
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obj->pltrelalim = (const Elf_RelA *)((caddr_t)obj->pltrela + pltrelasz);
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if (dyn_rpath != NULL) {
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_rtld_add_paths(&obj->rpaths, obj->strtab +
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dyn_rpath->d_un.d_val, true);
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}
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}
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/*
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* Process a shared object's program header. This is used only for the
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* main program, when the kernel has already loaded the main program
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* into memory before calling the dynamic linker. It creates and
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* returns an Obj_Entry structure.
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*/
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Obj_Entry *
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_rtld_digest_phdr(phdr, phnum, entry)
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const Elf_Phdr *phdr;
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int phnum;
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caddr_t entry;
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{
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Obj_Entry *obj;
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const Elf_Phdr *phlimit = phdr + phnum;
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const Elf_Phdr *ph;
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int nsegs = 0;
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obj = _rtld_obj_new();
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for (ph = phdr; ph < phlimit; ++ph) {
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switch (ph->p_type) {
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case PT_PHDR:
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assert((const Elf_Phdr *) ph->p_vaddr == phdr);
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obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
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obj->phsize = ph->p_memsz;
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break;
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case PT_INTERP:
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obj->interp = (const char *) ph->p_vaddr;
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break;
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case PT_LOAD:
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assert(nsegs < 2);
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if (nsegs == 0) { /* First load segment */
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obj->vaddrbase = round_down(ph->p_vaddr);
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obj->mapbase = (caddr_t) obj->vaddrbase;
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obj->relocbase = obj->mapbase - obj->vaddrbase;
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obj->textsize = round_up(ph->p_vaddr +
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ph->p_memsz) - obj->vaddrbase;
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} else { /* Last load segment */
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obj->mapsize = round_up(ph->p_vaddr +
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ph->p_memsz) - obj->vaddrbase;
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}
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++nsegs;
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break;
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case PT_DYNAMIC:
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obj->dynamic = (Elf_Dyn *) ph->p_vaddr;
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break;
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}
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}
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assert(nsegs == 2);
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obj->entry = entry;
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return obj;
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}
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