/*      $NetBSD: elf_data.c,v 1.5 2024/03/03 17:37:33 christos Exp $    */

/*-
* Copyright (c) 2006,2008,2011 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 <errno.h>
#include <libelf.h>
#include <stdint.h>
#include <stdlib.h>

#include "_libelf.h"

__RCSID("$NetBSD: elf_data.c,v 1.5 2024/03/03 17:37:33 christos Exp $");
ELFTC_VCSID("Id: elf_data.c 3977 2022-05-01 06:45:34Z jkoshy");

Elf_Data *
elf_getdata(Elf_Scn *s, Elf_Data *ed)
{
       Elf *e;
       unsigned int sh_type;
       int elfclass, elftype;
       size_t count, fsz, msz;
       struct _Libelf_Data *d;
       uint64_t sh_align, sh_offset, sh_size, raw_size;
       _libelf_translator_function *xlate;

       d = (struct _Libelf_Data *) ed;

       if (s == NULL || (e = s->s_elf) == NULL ||
           (d != NULL && s != d->d_scn)) {
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       assert(e->e_kind == ELF_K_ELF);

       if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
               return (&d->d_data);

       if (d != NULL)
               return (STAILQ_NEXT(d, d_next) ?
                   &STAILQ_NEXT(d, d_next)->d_data : NULL);

       if (e->e_rawfile == NULL) {
               /*
                * In the ELF_C_WRITE case, there is no source that
                * can provide data for the section.
                */
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       elfclass = e->e_class;

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

       if (elfclass == ELFCLASS32) {
               sh_type   = s->s_shdr.s_shdr32.sh_type;
               sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
               sh_size   = (uint64_t) s->s_shdr.s_shdr32.sh_size;
               sh_align  = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
       } else {
               sh_type   = s->s_shdr.s_shdr64.sh_type;
               sh_offset = s->s_shdr.s_shdr64.sh_offset;
               sh_size   = s->s_shdr.s_shdr64.sh_size;
               sh_align  = s->s_shdr.s_shdr64.sh_addralign;
       }

       if (sh_type == SHT_NULL) {
               LIBELF_SET_ERROR(SECTION, 0);
               return (NULL);
       }

       raw_size = (uint64_t) e->e_rawsize;
       if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
           elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
           (sh_offset > raw_size || sh_size > raw_size - sh_offset))) {
               LIBELF_SET_ERROR(SECTION, 0);
               return (NULL);
       }

       if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
           (elftype, (size_t) 1, e->e_version)) == 0) {
               LIBELF_SET_ERROR(UNIMPL, 0);
               return (NULL);
       }

       if (sh_size % fsz) {
               LIBELF_SET_ERROR(SECTION, 0);
               return (NULL);
       }

       if (sh_size / fsz > SIZE_MAX) {
               LIBELF_SET_ERROR(RANGE, 0);
               return (NULL);
       }

       count = (size_t) (sh_size / fsz);

       if ((msz = _libelf_msize(elftype, elfclass, e->e_version)) == 0)
               return (NULL);

       if (count > 0 && msz > SIZE_MAX / count) {
               LIBELF_SET_ERROR(RANGE, 0);
               return (NULL);
       }

       assert(msz > 0);
       assert(count <= SIZE_MAX);
       assert(msz * count <= SIZE_MAX);

       if ((d = _libelf_allocate_data(s)) == NULL)
               return (NULL);

       d->d_data.d_buf     = NULL;
       d->d_data.d_off     = 0;
       d->d_data.d_align   = sh_align;
       d->d_data.d_size    = msz * count;
       d->d_data.d_type    = elftype;
       d->d_data.d_version = e->e_version;

       if (sh_type == SHT_NOBITS || sh_size == 0) {
               STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
               return (&d->d_data);
       }

       if ((d->d_data.d_buf = malloc(msz * count)) == NULL) {
               (void) _libelf_release_data(d);
               LIBELF_SET_ERROR(RESOURCE, 0);
               return (NULL);
       }

       d->d_flags  |= LIBELF_F_DATA_MALLOCED;

       xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass,
           _libelf_elfmachine(e));
       if (!(*xlate)(d->d_data.d_buf, (size_t) d->d_data.d_size,
           e->e_rawfile + sh_offset, count,
           e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
               _libelf_release_data(d);
               LIBELF_SET_ERROR(DATA, 0);
               return (NULL);
       }

       STAILQ_INSERT_TAIL(&s->s_data, d, d_next);

       return (&d->d_data);
}

Elf_Data *
elf_newdata(Elf_Scn *s)
{
       Elf *e;
       struct _Libelf_Data *d;

       if (s == NULL || (e = s->s_elf) == NULL) {
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       assert(e->e_kind == ELF_K_ELF);

       /*
        * elf_newdata() has to append a data descriptor, so
        * bring in existing section data if not already present.
        */
       if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
               if (elf_getdata(s, NULL) == NULL)
                       return (NULL);

       if ((d = _libelf_allocate_data(s)) == NULL)
               return (NULL);

       STAILQ_INSERT_TAIL(&s->s_data, d, d_next);

       d->d_data.d_align = 1;
       d->d_data.d_buf = NULL;
       d->d_data.d_off = (uint64_t) ~0;
       d->d_data.d_size = 0;
       d->d_data.d_type = ELF_T_BYTE;
       d->d_data.d_version = LIBELF_PRIVATE(version);

       (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);

       return (&d->d_data);
}

/*
* Retrieve a data descriptor for raw (untranslated) data for section
* `s'.
*/

Elf_Data *
elf_rawdata(Elf_Scn *s, Elf_Data *ed)
{
       Elf *e;
       int elf_class;
       uint32_t sh_type;
       struct _Libelf_Data *d;
       uint64_t sh_align, sh_offset, sh_size, raw_size;

       if (s == NULL || (e = s->s_elf) == NULL || e->e_rawfile == NULL) {
               LIBELF_SET_ERROR(ARGUMENT, 0);
               return (NULL);
       }

       assert(e->e_kind == ELF_K_ELF);

       d = (struct _Libelf_Data *) ed;

       if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
               return (&d->d_data);

       if (d != NULL)
               return (&STAILQ_NEXT(d, d_next)->d_data);

       elf_class = e->e_class;

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

       if (elf_class == ELFCLASS32) {
               sh_type   = s->s_shdr.s_shdr32.sh_type;
               sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
               sh_size   = (uint64_t) s->s_shdr.s_shdr32.sh_size;
               sh_align  = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
       } else {
               sh_type   = s->s_shdr.s_shdr64.sh_type;
               sh_offset = s->s_shdr.s_shdr64.sh_offset;
               sh_size   = s->s_shdr.s_shdr64.sh_size;
               sh_align  = s->s_shdr.s_shdr64.sh_addralign;
       }

       if (sh_type == SHT_NULL) {
               LIBELF_SET_ERROR(SECTION, 0);
               return (NULL);
       }

       raw_size = (uint64_t) e->e_rawsize;
       if (sh_type != SHT_NOBITS &&
           (sh_offset > raw_size || sh_size > raw_size - sh_offset)) {
               LIBELF_SET_ERROR(SECTION, 0);
               return (NULL);
       }

       if ((d = _libelf_allocate_data(s)) == NULL)
               return (NULL);

       d->d_data.d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
           e->e_rawfile + sh_offset;
       d->d_data.d_off     = 0;
       d->d_data.d_align   = sh_align;
       d->d_data.d_size    = sh_size;
       d->d_data.d_type    = ELF_T_BYTE;
       d->d_data.d_version = e->e_version;

       STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);

       return (&d->d_data);
}

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