/*      $NetBSD: libelf_phdr.c,v 1.5 2024/03/03 17:37:34 christos Exp $ */

/*-
* Copyright (c) 2006,2008 Joseph Koshy
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/

#if HAVE_NBTOOL_CONFIG_H
# include "nbtool_config.h"
#endif

#include <sys/cdefs.h>

#include <assert.h>
#include <gelf.h>
#include <libelf.h>
#include <stdlib.h>

#include "_libelf.h"

__RCSID("$NetBSD: libelf_phdr.c,v 1.5 2024/03/03 17:37:34 christos Exp $");
ELFTC_VCSID("Id: libelf_phdr.c 3977 2022-05-01 06:45:34Z jkoshy");

void *
_libelf_getphdr(Elf *e, int ec)
{
       size_t phnum;
       size_t fsz, msz;
       uint64_t phoff;
       Elf32_Ehdr *eh32;
       Elf64_Ehdr *eh64;
       void *ehdr, *phdr;
       _libelf_translator_function *xlator;

       assert(ec == ELFCLASS32 || ec == ELFCLASS64);

       if (e == NULL) {
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       if ((phdr = (ec == ELFCLASS32 ?
                (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
                (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
               return (phdr);

       /*
        * Check the PHDR related fields in the EHDR for sanity.
        */

       if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
               return (NULL);

       phnum = e->e_u.e_elf.e_nphdr;

       if (ec == ELFCLASS32) {
               eh32      = (Elf32_Ehdr *) ehdr;
               phoff     = (uint64_t) eh32->e_phoff;
       } else {
               eh64      = (Elf64_Ehdr *) ehdr;
               phoff     = (uint64_t) eh64->e_phoff;
       }

       fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);

       assert(fsz > 0);

       if (phoff + fsz < phoff) {      /* Numeric overflow. */
               LIBELF_SET_ERROR(HEADER, 0);
               return (NULL);
       }

       if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
               LIBELF_SET_ERROR(HEADER, 0);
               return (NULL);
       }

       if ((msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT)) == 0)
               return (NULL);

       if ((phdr = calloc(phnum, msz)) == NULL) {
               LIBELF_SET_ERROR(RESOURCE, 0);
               return (NULL);
       }

       if (ec == ELFCLASS32)
               e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
       else
               e->e_u.e_elf.e_phdr.e_phdr64 = phdr;


       xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec,
           _libelf_elfmachine(e));
       (*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum,
           e->e_byteorder != LIBELF_PRIVATE(byteorder));

       return (phdr);
}

void *
_libelf_newphdr(Elf *e, int ec, size_t count)
{
       void *ehdr, *newphdr, *oldphdr;
       size_t msz;

       if (e == NULL) {
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
               LIBELF_SET_ERROR(SEQUENCE, 0);
               return (NULL);
       }

       assert(e->e_class == ec);
       assert(ec == ELFCLASS32 || ec == ELFCLASS64);
       assert(e->e_version == EV_CURRENT);

       if ((msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version)) == 0)
               return (NULL);

       newphdr = NULL;
       if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
               LIBELF_SET_ERROR(RESOURCE, 0);
               return (NULL);
       }

       if (ec == ELFCLASS32) {
               if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
                       free(oldphdr);
               e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
       } else {
               if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
                       free(oldphdr);
               e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
       }

       e->e_u.e_elf.e_nphdr = count;

       elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);

       return (newphdr);
}