/*

  Copyright (C) 2014-2020 David Anderson. All Rights Reserved.

  This program is free software; you can redistribute it
  and/or modify it under the terms of version 2.1 of the
  GNU Lesser General Public License as published by the Free
  Software Foundation.

  This program is distributed in the hope that it would be
  useful, but WITHOUT ANY WARRANTY; without even the implied
  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.

  Further, this software is distributed without any warranty
  that it is free of the rightful claim of any third person
  regarding infringement or the like.  Any license provided
  herein, whether implied or otherwise, applies only to this
  software file.  Patent licenses, if any, provided herein
  do not apply to combinations of this program with other
  software, or any other product whatsoever.

  You should have received a copy of the GNU Lesser General
  Public License along with this program; if not, write the
  Free Software Foundation, Inc., 51 Franklin Street - Fifth
  Floor, Boston MA 02110-1301, USA.
*/

#include "config.h"
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif /* HAVE_STDLIB_H */
#ifdef HAVE_STDINT_H
#include <stdint.h> /* For uintptr_t */
#endif /* HAVE_STDINT_H */
#include "dwarf_incl.h"
#include "dwarf_alloc.h"
#include "dwarf_error.h"
#include "dwarf_util.h"
#include "dwarfstring.h"
#include "memcpy_swap.h"
#include "dwarf_gdbindex.h"

#define TRUE 1
#define FALSE 0

/*  The dwarf_util macro READ_UNALIGNED
    cannot be directly used because
    gdb defines the section contents of
    .gdb_index as little-endian always.
*/

#if WORDS_BIGENDIAN   /* meaning on this host */
#define READ_GDBINDEX(dest,desttype, source, length)                     \
    do {                                                                 \
        BIGGEST_UINT _ltmp = 0;                                          \
        _dwarf_memcpy_swap_bytes((((char *)(&_ltmp)) + sizeof(_ltmp) - length), \
            source, length) ;                                            \
        dest = (desttype)_ltmp;                                          \
    } while (0)
#else /* little-endian on this host */
#define READ_GDBINDEX(dest,desttype, source, length)                     \
    do {                                                                 \
        BIGGEST_UINT _ltmp = 0;                                          \
        memcpy(((char *)(&_ltmp)) ,            \
            source, length) ;                                            \
        dest = (desttype)_ltmp;                                          \
    } while (0)

#endif


struct gi_fileheader_s {
    char gfs [4][6];
};

struct dwarf_64bitpair {
    gdbindex_64 offset;
    gdbindex_64 length;
};

static int
set_base(Dwarf_Debug dbg,
    struct Dwarf_Gdbindex_array_instance_s * hdr,
    Dwarf_Small *start,
    Dwarf_Small *end,
    /* entrylen is the length of a single struct as seen in the object. */
    Dwarf_Unsigned entrylen,
    /* The size of each field in the struct in the object. */
    Dwarf_Unsigned fieldlen,
    enum gdbindex_type_e type,
    Dwarf_Error * err)
{

    if (type == git_std || type == git_cuvec) {
        /*  cuvec is sort of a fake as a simple
            section, but a useful one. */
        Dwarf_Unsigned count = 0;
        if( end < start) {
            _dwarf_error(dbg, err,DW_DLE_GDB_INDEX_COUNT_ERROR);
            return DW_DLV_ERROR;
        }
        count = end - start;
        count = count / entrylen;
        hdr->dg_type = type;
        hdr->dg_base = start;
        hdr->dg_count = count;
        hdr->dg_entry_length = entrylen;
        hdr->dg_fieldlen = fieldlen;
    } else {
        /* address area. */
        /* 64bit, 64bit, offset. Then 32bit pad. */
        Dwarf_Unsigned count = 0;
        hdr->dg_base = start;
        if( end < start) {
            _dwarf_error(dbg, err,DW_DLE_GDB_INDEX_COUNT_ADDR_ERROR);
            return DW_DLV_ERROR;
        }
        /* entry length includes pad. */
        hdr->dg_entry_length = 2*sizeof(gdbindex_64) +
            DWARF_32BIT_SIZE;
        count = end - start;
        count = count / hdr->dg_entry_length;
        hdr->dg_count = count;
        /*  The dg_fieldlen is a fake, the fields are not
            all the same length. */
        hdr->dg_fieldlen = DWARF_32BIT_SIZE;
        hdr->dg_type = type;
    }
    return DW_DLV_OK;
}

int
dwarf_gdbindex_header(Dwarf_Debug dbg,
    Dwarf_Gdbindex * gdbindexptr,
    Dwarf_Unsigned * version,
    Dwarf_Unsigned * cu_list_offset,
    Dwarf_Unsigned * types_cu_list_offset,
    Dwarf_Unsigned * address_area_offset,
    Dwarf_Unsigned * symbol_table_offset,
    Dwarf_Unsigned * constant_pool_offset,
    Dwarf_Unsigned * section_size,
    Dwarf_Unsigned * unused_reserved,
    const char    ** section_name,
    Dwarf_Error    * error)
{

    struct gi_fileheader_s header;
    Dwarf_Gdbindex indexptr = 0;
    int res = DW_DLV_ERROR;

    if (!dbg->de_debug_gdbindex.dss_size) {
        return DW_DLV_NO_ENTRY;
    }
    if (!dbg->de_debug_gdbindex.dss_data) {
        res = _dwarf_load_section(dbg, &dbg->de_debug_gdbindex,error);
        if (res != DW_DLV_OK) {
            return res;
        }
    }

    if (dbg->de_debug_gdbindex.dss_size <
        sizeof(struct gi_fileheader_s) ) {
        _dwarf_error(dbg, error, DW_DLE_ERRONEOUS_GDB_INDEX_SECTION);
        return (DW_DLV_ERROR);
    }
    memcpy(&header,dbg->de_debug_gdbindex.dss_data,
        sizeof(struct gi_fileheader_s));
    indexptr = (Dwarf_Gdbindex)_dwarf_get_alloc(dbg,DW_DLA_GDBINDEX,1);
    if (indexptr == NULL) {
        _dwarf_error(dbg, error, DW_DLE_ALLOC_FAIL);
        return (DW_DLV_ERROR);
    }

    indexptr->gi_dbg = dbg;
    indexptr->gi_section_data = dbg->de_debug_gdbindex.dss_data;
    indexptr->gi_section_length = dbg->de_debug_gdbindex.dss_size;
    READ_GDBINDEX(indexptr->gi_version ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data,
        DWARF_32BIT_SIZE);
    READ_GDBINDEX(indexptr->gi_cu_list_offset ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data + DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE);
    READ_GDBINDEX(indexptr->gi_types_cu_list_offset ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data + 2*DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE);
    READ_GDBINDEX(indexptr->gi_address_area_offset ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data + 3*DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE);
    READ_GDBINDEX(indexptr->gi_symbol_table_offset ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data + 4*DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE);
    READ_GDBINDEX(indexptr->gi_constant_pool_offset ,Dwarf_Unsigned,
        dbg->de_debug_gdbindex.dss_data + 5*DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE);

    res = set_base(dbg,&indexptr->gi_culisthdr,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_cu_list_offset,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_types_cu_list_offset,
        2*sizeof(gdbindex_64),
        sizeof(gdbindex_64),
        git_std,error);
    if (res == DW_DLV_ERROR) {
        return res;
    }
    res = set_base(dbg,&indexptr->gi_typesculisthdr,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_types_cu_list_offset,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_address_area_offset,
        3*sizeof(gdbindex_64),
        sizeof(gdbindex_64),
        git_std,error);
    if (res == DW_DLV_ERROR) {
        return res;
    }
    res = set_base(dbg,&indexptr->gi_addressareahdr,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_address_area_offset,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_symbol_table_offset,
        3*sizeof(gdbindex_64),
        sizeof(gdbindex_64),
        git_address,error);
    if (res == DW_DLV_ERROR) {
        return res;
    }
    res = set_base(dbg,&indexptr->gi_symboltablehdr,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_symbol_table_offset,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_constant_pool_offset,
        2*DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE,
        git_std,error);
    if (res == DW_DLV_ERROR) {
        return res;
    }
    res = set_base(dbg,&indexptr->gi_cuvectorhdr,
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_constant_pool_offset,
        /*  There is no real single vector size.
            but we'll use the entire rest as if there was. */
        dbg->de_debug_gdbindex.dss_data + indexptr->gi_section_length,
        DWARF_32BIT_SIZE,
        DWARF_32BIT_SIZE,
        git_cuvec,error);
    if (res == DW_DLV_ERROR) {
        return res;
    }

    /* Really just pointing to constant pool area. */
    indexptr->gi_string_pool = dbg->de_debug_gdbindex.dss_data +
        indexptr->gi_constant_pool_offset;
    *gdbindexptr          = indexptr;
    *version              = indexptr->gi_version;
    *cu_list_offset       = indexptr->gi_cu_list_offset;
    *types_cu_list_offset = indexptr->gi_types_cu_list_offset;
    *address_area_offset  = indexptr->gi_address_area_offset;
    *symbol_table_offset  = indexptr->gi_symbol_table_offset;
    *constant_pool_offset = indexptr->gi_constant_pool_offset;
    *section_size         = indexptr->gi_section_length;
    *unused_reserved = 0;
    *section_name  =        dbg->de_debug_gdbindex.dss_name;
    return DW_DLV_OK;


}


int
dwarf_gdbindex_culist_array(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned       * list_length,
    UNUSEDARG Dwarf_Error          * error)
{
    *list_length = gdbindexptr->gi_culisthdr.dg_count;
    return DW_DLV_OK;
}

/*  entryindex: 0 to list_length-1 */
int
dwarf_gdbindex_culist_entry(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned   entryindex,
    Dwarf_Unsigned * cu_offset,
    Dwarf_Unsigned * cu_length,
    Dwarf_Error    * error)
{
    Dwarf_Unsigned max =  gdbindexptr->gi_culisthdr.dg_count;
    Dwarf_Small * base = 0;
    Dwarf_Unsigned offset = 0;
    Dwarf_Unsigned length = 0;
    unsigned fieldlen = gdbindexptr->gi_culisthdr.dg_fieldlen;

    if (entryindex >= max) {
        _dwarf_error(gdbindexptr->gi_dbg, error,DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }
    base = gdbindexptr->gi_culisthdr.dg_base;
    base += entryindex*gdbindexptr->gi_culisthdr.dg_entry_length;

    READ_GDBINDEX(offset ,Dwarf_Unsigned,
        base,
        fieldlen);
    READ_GDBINDEX(length ,Dwarf_Unsigned,
        base+ fieldlen,
        fieldlen);
    *cu_offset = offset;
    *cu_length = length;
    return DW_DLV_OK;
}

int
dwarf_gdbindex_types_culist_array(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned       * list_length,
    UNUSEDARG Dwarf_Error          * error)
{
    *list_length = gdbindexptr->gi_typesculisthdr.dg_count;
    return DW_DLV_OK;
}

/*  entryindex: 0 to list_length-1 */
int
dwarf_gdbindex_types_culist_entry(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned   entryindex,
    Dwarf_Unsigned * t_offset,
    Dwarf_Unsigned * t_length,
    Dwarf_Unsigned * t_signature,
    Dwarf_Error    * error)
{
    Dwarf_Unsigned max =  gdbindexptr->gi_typesculisthdr.dg_count;
    Dwarf_Small * base = 0;
    Dwarf_Unsigned offset = 0;
    Dwarf_Unsigned length = 0;
    Dwarf_Unsigned signature = 0;
    unsigned fieldlen = gdbindexptr->gi_typesculisthdr.dg_fieldlen;

    if (entryindex >= max) {
        _dwarf_error(gdbindexptr->gi_dbg, error,DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }
    base = gdbindexptr->gi_typesculisthdr.dg_base;
    base += entryindex*gdbindexptr->gi_typesculisthdr.dg_entry_length;

    READ_GDBINDEX(offset ,Dwarf_Unsigned,
        base,
        fieldlen);
    READ_GDBINDEX(length ,Dwarf_Unsigned,
        base+ (1*fieldlen),
        fieldlen);
    READ_GDBINDEX(signature ,Dwarf_Unsigned,
        base+ (2*fieldlen),
        fieldlen);
    *t_offset = offset;
    *t_length = length;
    *t_signature = signature;
    return DW_DLV_OK;
}

int
dwarf_gdbindex_addressarea(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned            * list_length,
    UNUSEDARG Dwarf_Error               * error)
{
    *list_length = gdbindexptr->gi_addressareahdr.dg_count;
    return DW_DLV_OK;
}

/*    entryindex: 0 to addressarea_list_length-1 */
int
dwarf_gdbindex_addressarea_entry(
    Dwarf_Gdbindex   gdbindexptr,
    Dwarf_Unsigned   entryindex,
    Dwarf_Unsigned * low_address,
    Dwarf_Unsigned * high_address,
    Dwarf_Unsigned * cu_index,
    Dwarf_Error    * error)
{
    Dwarf_Unsigned max =  gdbindexptr->gi_addressareahdr.dg_count;
    Dwarf_Small * base = 0;
    Dwarf_Unsigned lowaddr = 0;
    Dwarf_Unsigned highaddr = 0;
    Dwarf_Unsigned cuindex = 0;

    if (entryindex >= max) {
        _dwarf_error(gdbindexptr->gi_dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }
    base = gdbindexptr->gi_addressareahdr.dg_base;
    base += entryindex*gdbindexptr->gi_addressareahdr.dg_entry_length;

    READ_GDBINDEX(lowaddr ,Dwarf_Unsigned,
        base,
        sizeof(gdbindex_64));
    READ_GDBINDEX(highaddr ,Dwarf_Unsigned,
        base+ (1*sizeof(gdbindex_64)),
        sizeof(gdbindex_64));
    READ_GDBINDEX(cuindex ,Dwarf_Unsigned,
        base+ (2*sizeof(gdbindex_64)),
        DWARF_32BIT_SIZE);
    *low_address = lowaddr;
    *high_address = highaddr;
    *cu_index = cuindex;
    return DW_DLV_OK;
}

int
dwarf_gdbindex_symboltable_array(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned            * list_length,
    UNUSEDARG Dwarf_Error               * error)
{
    *list_length = gdbindexptr->gi_symboltablehdr.dg_count;
    return DW_DLV_OK;
}

/*  entryindex: 0 to symtab_list_length-1 */
int
dwarf_gdbindex_symboltable_entry(
    Dwarf_Gdbindex   gdbindexptr,
    Dwarf_Unsigned   entryindex,
    Dwarf_Unsigned * string_offset,
    Dwarf_Unsigned * cu_vector_offset,
    Dwarf_Error    * error)
{
    Dwarf_Unsigned max =  gdbindexptr->gi_symboltablehdr.dg_count;
    Dwarf_Small * base = 0;
    Dwarf_Unsigned symoffset = 0;
    Dwarf_Unsigned cuoffset = 0;
    unsigned fieldlen = gdbindexptr->gi_symboltablehdr.dg_fieldlen;

    if (entryindex >= max) {
        _dwarf_error(gdbindexptr->gi_dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }
    base = gdbindexptr->gi_symboltablehdr.dg_base;
    base += entryindex*gdbindexptr->gi_symboltablehdr.dg_entry_length;

    READ_GDBINDEX(symoffset ,Dwarf_Unsigned,
        base,
        fieldlen);
    READ_GDBINDEX(cuoffset ,Dwarf_Unsigned,
        base + fieldlen,
        fieldlen);
    *string_offset = symoffset;
    *cu_vector_offset = cuoffset;
    return DW_DLV_OK;
}

int
dwarf_gdbindex_cuvector_length(Dwarf_Gdbindex gdbindex,
    Dwarf_Unsigned   cuvector_offset,
    Dwarf_Unsigned * innercount,
    Dwarf_Error    * error)
{
    Dwarf_Small *base = gdbindex->gi_cuvectorhdr.dg_base;
    Dwarf_Small *end = gdbindex->gi_section_data + gdbindex->gi_section_length;
    Dwarf_Unsigned val = 0;
    unsigned fieldlen =  gdbindex->gi_cuvectorhdr.dg_entry_length;

    base += cuvector_offset;
    if ((base + fieldlen) >= end) {
        _dwarf_error(gdbindex->gi_dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }

    READ_GDBINDEX(val,Dwarf_Unsigned,
        base,
        fieldlen);
    *innercount = val;
    return DW_DLV_OK;
}

int
dwarf_gdbindex_cuvector_inner_attributes(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned   cuvector_offset,
    Dwarf_Unsigned   innerindex,
    /* The attr_value is a field of bits. For expanded version
        use  dwarf_gdbindex_instance_expand_value() */
    Dwarf_Unsigned * attributes,
    Dwarf_Error    * error)
{
    Dwarf_Small *base = gdbindexptr->gi_cuvectorhdr.dg_base;
    Dwarf_Small *end = gdbindexptr->gi_section_data +
        gdbindexptr->gi_section_length;
    Dwarf_Unsigned val = 0;
    unsigned fieldlen = gdbindexptr->gi_cuvectorhdr.dg_entry_length;

    base += cuvector_offset;
    if ((base+fieldlen) >= end) {
        _dwarf_error(gdbindexptr->gi_dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR);
        return DW_DLV_ERROR;
    }
    base += fieldlen;
    base += innerindex*fieldlen;

    READ_GDBINDEX(val ,Dwarf_Unsigned,
        base,
        fieldlen);
    *attributes = val;
    return DW_DLV_OK;
}


int
dwarf_gdbindex_cuvector_instance_expand_value(
    UNUSEDARG Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned   value,
    Dwarf_Unsigned * cu_index,
    Dwarf_Unsigned * reserved1,
    Dwarf_Unsigned * symbol_kind,
    Dwarf_Unsigned * is_static,
    UNUSEDARG Dwarf_Error    * error)
{
    *cu_index =    value         & 0xffffff;
    *reserved1 =   (value >> 24) & 0xf;
    *symbol_kind = (value >> 28) & 0x7;
    *is_static =   (value >> 31) & 1;
    return DW_DLV_OK;
}


/*  The strings in the pool follow (in memory) the cu index
    set and are NUL terminated. */
int
dwarf_gdbindex_string_by_offset(Dwarf_Gdbindex gdbindexptr,
    Dwarf_Unsigned   stringoffsetinpool,
    const char    ** string_ptr,
    Dwarf_Error   *  error)
{
    Dwarf_Small *pooldata = 0;
    Dwarf_Small *section_end = 0;
    Dwarf_Small *stringitself = 0;
    Dwarf_Debug dbg = 0;
    int res = 0;

    if (!gdbindexptr) {
        dwarfstring m;

        dwarfstring_constructor(&m);
        dwarfstring_append(&m,"DW_DLE_GDB_INDEX_INDEX_ERROR: "
            "The gdbindex pointer to "
            "dwarf_gdbindex_string_by_offset()"
            " is NULL");
        _dwarf_error_string(gdbindexptr->gi_dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR,
            dwarfstring_string(&m));
        dwarfstring_destructor(&m);
        return DW_DLV_ERROR;
    }
    dbg = gdbindexptr->gi_dbg;
    if (!dbg) {
        dwarfstring m;

        dwarfstring_constructor(&m);
        dwarfstring_append(&m,"DW_DLE_GDB_INDEX_INDEX_ERROR: "
            "The gdbindex Dwarf_Debug in"
            "dwarf_gdbindex_string_by_offset()"
            " is NULL");
        _dwarf_error_string(dbg, error,
            DW_DLE_GDB_INDEX_INDEX_ERROR,
            dwarfstring_string(&m));
        dwarfstring_destructor(&m);
        return DW_DLV_ERROR;
    }
    pooldata = gdbindexptr->gi_section_data +
        gdbindexptr->gi_constant_pool_offset;
    section_end = gdbindexptr->gi_section_data +
        gdbindexptr->gi_section_length;
    stringitself = pooldata + stringoffsetinpool;
    if (stringitself > section_end) {
        dwarfstring m;

        dwarfstring_constructor(&m);
        dwarfstring_append_printf_u(&m,
            "DW_DLE_GDBINDEX_STRING_ERROR: "
            "The dwarf_gdbindex_string_by_offset() "
            "string starts past the end of the "
            "section at section_offset 0x%"
            DW_PR_XZEROS DW_PR_DUx  ".",
            (Dwarf_Unsigned)(uintptr_t)
            (stringitself -gdbindexptr->gi_section_data));
        _dwarf_error_string(dbg, error,
            DW_DLE_GDBINDEX_STRING_ERROR,
            dwarfstring_string(&m));
        dwarfstring_destructor(&m);
        return DW_DLV_ERROR;
    }
    res = _dwarf_check_string_valid(dbg,pooldata,
        stringitself, section_end,
        DW_DLE_GDBINDEX_STRING_ERROR,
        error);
    if (res != DW_DLV_OK) {
        return res;
    }
    *string_ptr = (const char *)stringitself;
    return DW_DLV_OK;
}




void
dwarf_gdbindex_free(Dwarf_Gdbindex indexptr)
{
    if(indexptr) {
        Dwarf_Debug dbg = indexptr->gi_dbg;
        dwarf_dealloc(dbg,indexptr,DW_DLA_GDBINDEX);
    }
}