/*
getdata.c - implementation of the elf_getdata(3) function.
Copyright (C) 1995 Michael Riepe <riepe@ifwsn4.ifw.uni-hannover.de>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include <private.h>

static Elf_Data*
_elf32_cook_scn(Elf *elf, Elf_Scn *scn, Scn_Data *sd) {
    Elf_Data src, dst;
    size_t fsize, msize;
    int flag = 0;

    src = dst = sd->sd_data;
    src.d_version = elf->e_version;
    fsize = _fsize32(src.d_version, src.d_type);
    elf_assert(fsize);
    msize = _msize32(dst.d_version, src.d_type);
    elf_assert(msize);
    if (fsize != msize) {
	dst.d_size = (dst.d_size / fsize) * msize;
    }

    elf_assert(elf->e_data);
    if (elf->e_rawdata != elf->e_data && dst.d_size <= src.d_size) {
	dst.d_buf = elf->e_data + scn->s_offset;
    }
    else if (!(dst.d_buf = malloc(dst.d_size))) {
	seterr(ERROR_MEM_SCNDATA);
	return NULL;
    }
    else {
	flag |= 1;
    }

    if (elf->e_rawdata) {
	src.d_buf = elf->e_rawdata + scn->s_offset;
    }
    else {
	if (src.d_size <= dst.d_size) {
	    src.d_buf = dst.d_buf;
	}
	else if (!(src.d_buf = malloc(src.d_size))) {
	    seterr(ERROR_IO_2BIG);
	    goto fail;
	}
	else {
	    flag |= 2;
	}

	if (!_elf_read(elf, src.d_buf, scn->s_offset, src.d_size)) {
	    goto fail;
	}
    }

    if (elf32_xlatetom(&dst, &src, elf->e_encoding)) {
	sd->sd_memdata = (char*)dst.d_buf;
	sd->sd_data = dst;
	if (flag & 2) {
	    free(src.d_buf);
	}
	if (flag & 1) {
	    sd->sd_free_data = 1;
	}
	else {
	    elf->e_cooked = 1;
	}
	return (Elf_Data*)sd;
    }

fail:
    if (flag & 2) {
	free(src.d_buf);
    }
    if (flag & 1) {
	free(dst.d_buf);
    }
    return NULL;
}

Elf_Data*
elf_getdata(Elf_Scn *scn, Elf_Data *data) {
    Scn_Data *sd = (Scn_Data*)data;
    Elf *elf;

    if (!scn) {
	return NULL;
    }
    elf_assert(scn->s_magic == SCN_MAGIC);
    if (scn->s_index == SHN_UNDEF) {
	seterr(ERROR_NULLSCN);
    }
    else if (sd) {
	if (sd->sd_scn == scn) {
	    /*
	     * sd_link allocated by elf_newdata().
	     */
	    return (Elf_Data*)sd->sd_link;
	}
	seterr(ERROR_SCNDATAMISMATCH);
    }
    else if ((sd = scn->s_data_1)) {
	elf = scn->s_elf;
	elf_assert(elf);
	elf_assert(elf->e_magic == ELF_MAGIC);
	if (sd->sd_freeme) {
	    /* allocated by elf_newdata() */
	    return (Elf_Data*)sd;
	}
	else if (scn->s_type == SHT_NULL) {
	    seterr(ERROR_NULLSCN);
	}
	else if (sd->sd_memdata) {
	    /* already cooked */
	    return (Elf_Data*)sd;
	}
	else if (scn->s_offset < 0 || scn->s_offset > elf->e_size) {
	    seterr(ERROR_OUTSIDE);
	}
	else if (scn->s_type == SHT_NOBITS || !scn->s_size) {
	    /* no data to read */
	    return (Elf_Data*)sd;
	}
	else if (scn->s_offset + scn->s_size > elf->e_size) {
	    seterr(ERROR_TRUNC_SCN);
	}
	else if (elf->e_class == ELFCLASS32) {
	    return _elf32_cook_scn(elf, scn, sd);
	}
	else if (valid_class(elf->e_class)) {
	    seterr(ERROR_UNIMPLEMENTED);
	}
	else {
	    seterr(ERROR_UNKNOWN_CLASS);
	}
    }
    return NULL;
}