File: dwarf_global.c

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dwarfutils 20180809-1
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/*

  Copyright (C) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
  Portions Copyright (C) 2007-2011 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>
#include "dwarf_incl.h"
#include "dwarf_alloc.h"
#include "dwarf_error.h"
#include "dwarf_util.h"
#include "dwarf_global.h"


#ifdef __sgi  /* __sgi should only be defined for IRIX/MIPS. */
/* The 'fixup' here intended for IRIX targets only.
   With a  2+GB Elf64 IRIX executable (under 4GB in size),
   some DIE offsets wrongly
   got the 32bit upper bit sign extended.  For the cu-header
   offset in the .debug_pubnames section  and in the
   .debug_aranges section.
   the 'varp' here is a pointer to an offset into .debug_info.
   We fix up the offset here if it seems advisable..

   As of June 2005 we have identified a series of mistakes
   in ldx64 that can cause this (64 bit values getting passed
   thru 32-bit signed knothole).
*/
void
_dwarf_fix_up_offset_irix(Dwarf_Debug dbg,
    Dwarf_Unsigned * varp, char *caller_site_name)
{

    Dwarf_Unsigned var = *varp;

#define UPPER33 0xffffffff80000000LL
#define LOWER32         0xffffffffLL
    /*  Restrict the hack to the known case. Upper 32 bits erroneously
        sign extended from lower 32 upper bit. */
    if ((var & UPPER33) == UPPER33) {
        var &= LOWER32;
        /* Apply the fix. Dreadful hack. */
        *varp = var;
    }
#undef UPPER33
#undef LOWER32
    return;
}
#endif  /* __sgi */


int
dwarf_get_globals(Dwarf_Debug dbg,
    Dwarf_Global ** globals,
    Dwarf_Signed * return_count, Dwarf_Error * error)
{
    int res = _dwarf_load_section(dbg, &dbg->de_debug_pubnames,error);
    if (res != DW_DLV_OK) {
        return res = 0;
    }
    if (!dbg->de_debug_pubnames.dss_size) {
        return (DW_DLV_NO_ENTRY);
    }


    return _dwarf_internal_get_pubnames_like_data(dbg,
        dbg->de_debug_pubnames.dss_data,
        dbg->de_debug_pubnames.dss_size,
        globals,
        return_count,
        error,
        DW_DLA_GLOBAL_CONTEXT,
        DW_DLA_GLOBAL,
        DW_DLE_PUBNAMES_LENGTH_BAD,
        DW_DLE_PUBNAMES_VERSION_ERROR);

}

/* Deallocating fully requires deallocating the list
   and all entries.  But some internal data is
   not exposed, so we need a function with internal knowledge.
*/

void
dwarf_globals_dealloc(Dwarf_Debug dbg, Dwarf_Global * dwgl,
    Dwarf_Signed count)
{
    _dwarf_internal_globals_dealloc(dbg, dwgl,
        count,
        DW_DLA_GLOBAL_CONTEXT,
        DW_DLA_GLOBAL, DW_DLA_LIST);
    return;
}

void
_dwarf_internal_globals_dealloc(Dwarf_Debug dbg, Dwarf_Global * dwgl,
    Dwarf_Signed count,
    int context_code,
    int global_code, int list_code)
{
    Dwarf_Signed i;
    struct Dwarf_Global_Context_s *gcp = 0;
    struct Dwarf_Global_Context_s *lastgcp = 0;

    for (i = 0; i < count; i++) {
        Dwarf_Global dgb = dwgl[i];

        gcp = dgb->gl_context;

        if (lastgcp != gcp) {
            lastgcp = gcp;
            dwarf_dealloc(dbg, gcp, context_code);
        }
        dwarf_dealloc(dbg, dgb, global_code);
    }
    dwarf_dealloc(dbg, dwgl, list_code);
    return;
}


/* Sweeps the complete  section.  */
int
_dwarf_internal_get_pubnames_like_data(Dwarf_Debug dbg,
    Dwarf_Small * section_data_ptr,
    Dwarf_Unsigned section_length,
    Dwarf_Global ** globals,
    Dwarf_Signed * return_count,
    Dwarf_Error * error,
    int context_code,
    int global_code,
    int length_err_num,
    int version_err_num)
{
    Dwarf_Small *pubnames_like_ptr = 0;
    Dwarf_Small *section_end_ptr = section_data_ptr +section_length;

    /*  Points to the context for the current set of global names, and
        contains information to identify the compilation-unit that the
        set refers to. */
    Dwarf_Global_Context pubnames_context = 0;

    Dwarf_Half version = 0;

    /*  Offset from the start of compilation-unit for the current
        global. */
    Dwarf_Off die_offset_in_cu = 0;

    Dwarf_Unsigned global_count = 0;

    /* Points to the current global read. */
    Dwarf_Global global = 0;

    /*  Used to chain the Dwarf_Global_s structs for creating contiguous
        list of pointers to the structs. */
    Dwarf_Chain curr_chain = 0;
    Dwarf_Chain prev_chain = 0;
    Dwarf_Chain head_chain = 0;

    /* Points to contiguous block of Dwarf_Global's to be returned. */
    Dwarf_Global *ret_globals = 0;

    /* Temporary counter. */
    Dwarf_Unsigned i = 0;

    if (dbg == NULL) {
        _dwarf_error(NULL, error, DW_DLE_DBG_NULL);
        return (DW_DLV_ERROR);
    }
    /* We will eventually need the .debug_info data. Load it now. */
    if (!dbg->de_debug_info.dss_data) {
        int res = _dwarf_load_debug_info(dbg, error);

        if (res != DW_DLV_OK) {
            return res;
        }
    }
    if (section_data_ptr == NULL) {
        return (DW_DLV_NO_ENTRY);
    }
    pubnames_like_ptr = section_data_ptr;
    do {
        Dwarf_Unsigned length = 0;
        int local_extension_size = 0;
        int local_length_size = 0;

        /*  Some compilers emit padding at the end of each cu's area.
            pubnames_ptr_past_end_cu records the true area end for the
            pubnames(like) content of a cu.
            Essentially the length in the header and the 0
            terminator of the data are redundant information. The
            dwarf2/3 spec does not mention what to do if the length is
            past the 0 terminator. So we take any bytes left after the 0
            as padding and ignore them. */
        Dwarf_Small *pubnames_ptr_past_end_cu = 0;


        pubnames_context = (Dwarf_Global_Context)
            _dwarf_get_alloc(dbg, context_code, 1);
        if (pubnames_context == NULL) {
            _dwarf_error(dbg, error, DW_DLE_ALLOC_FAIL);
        return (DW_DLV_ERROR);
        }
        /*  READ_AREA_LENGTH updates pubnames_like_ptr for consumed
            bytes. */
        READ_AREA_LENGTH_CK(dbg, length, Dwarf_Unsigned,
            pubnames_like_ptr, local_length_size,
            local_extension_size,error,section_length,section_end_ptr);
        pubnames_context->pu_length_size = local_length_size;
        pubnames_context->pu_extension_size = local_extension_size;
        pubnames_context->pu_dbg = dbg;

        pubnames_ptr_past_end_cu = pubnames_like_ptr + length;

        READ_UNALIGNED_CK(dbg, version, Dwarf_Half,
            pubnames_like_ptr, DWARF_HALF_SIZE,
            error,section_end_ptr);
        pubnames_like_ptr += DWARF_HALF_SIZE;
        /* ASSERT: DW_PUBNAMES_VERSION2 == DW_PUBTYPES_VERSION2 */
        if (version != DW_PUBNAMES_VERSION2) {
            _dwarf_error(dbg, error, version_err_num);
            return (DW_DLV_ERROR);
        }

        /* Offset of CU header in debug section. */
        READ_UNALIGNED_CK(dbg, pubnames_context->pu_offset_of_cu_header,
            Dwarf_Off, pubnames_like_ptr,
            pubnames_context->pu_length_size,
            error,section_end_ptr);
        pubnames_like_ptr += pubnames_context->pu_length_size;

        FIX_UP_OFFSET_IRIX_BUG(dbg,
            pubnames_context->pu_offset_of_cu_header,
            "pubnames cu header offset");


        READ_UNALIGNED_CK(dbg, pubnames_context->pu_info_length,
            Dwarf_Unsigned, pubnames_like_ptr,
            pubnames_context->pu_length_size,
            error,section_end_ptr);
        pubnames_like_ptr += pubnames_context->pu_length_size;

        if (pubnames_like_ptr > (section_data_ptr + section_length)) {
            _dwarf_error(dbg, error, length_err_num);
            return (DW_DLV_ERROR);
        }

        /*  Read initial offset (of DIE within CU) of a pubname, final
            entry is not a pair, just a zero offset. */
        READ_UNALIGNED_CK(dbg, die_offset_in_cu, Dwarf_Off,
            pubnames_like_ptr,
            pubnames_context->pu_length_size,
            error,section_end_ptr);
        pubnames_like_ptr += pubnames_context->pu_length_size;
        FIX_UP_OFFSET_IRIX_BUG(dbg,
            die_offset_in_cu, "offset of die in cu");

        /* Loop thru pairs. DIE off with CU followed by string. */
        while (die_offset_in_cu != 0) {
            int res;

            /*  Already read offset, pubnames_like_ptr now points to the
                string. */
            global =
                (Dwarf_Global) _dwarf_get_alloc(dbg, global_code, 1);
            if (global == NULL) {
                _dwarf_error(dbg, error, DW_DLE_ALLOC_FAIL);
                return (DW_DLV_ERROR);
            }
            global_count++;

            global->gl_context = pubnames_context;

            global->gl_named_die_offset_within_cu = die_offset_in_cu;

            global->gl_name = pubnames_like_ptr;

            res = _dwarf_check_string_valid(dbg,section_data_ptr,
                pubnames_like_ptr,section_end_ptr,
                DW_DLE_STRING_OFF_END_PUBNAMES_LIKE,error);
            if (res != DW_DLV_OK) {
                return res;
            }
            pubnames_like_ptr = pubnames_like_ptr +
                strlen((char *) pubnames_like_ptr) + 1;

            /* Finish off current entry chain */
            curr_chain =
                (Dwarf_Chain) _dwarf_get_alloc(dbg, DW_DLA_CHAIN, 1);
            if (curr_chain == NULL) {
                _dwarf_error(dbg, error, DW_DLE_ALLOC_FAIL);
                return (DW_DLV_ERROR);
            }

            /* Put current global on singly_linked list. */
            curr_chain->ch_item = (Dwarf_Global) global;

            if (head_chain == NULL)
                head_chain = prev_chain = curr_chain;
            else {
                prev_chain->ch_next = curr_chain;
                prev_chain = curr_chain;
            }

            /* Fead offset for the *next* entry */
            READ_UNALIGNED_CK(dbg, die_offset_in_cu, Dwarf_Off,
                pubnames_like_ptr, pubnames_context->pu_length_size,
                error,section_end_ptr);
            pubnames_like_ptr += pubnames_context->pu_length_size;
            FIX_UP_OFFSET_IRIX_BUG(dbg,
                die_offset_in_cu, "offset of next die in cu");
            if (pubnames_like_ptr > (section_data_ptr + section_length)) {
                _dwarf_error(dbg, error, length_err_num);
                return (DW_DLV_ERROR);
            }
        }
        /* ASSERT: die_offset_in_cu == 0 */
        if (pubnames_like_ptr > pubnames_ptr_past_end_cu) {
            /* This is some kind of error. This simply cannot happen.
            The encoding is wrong or the length in the header for
            this cu's contribution is wrong. */
            _dwarf_error(dbg, error, length_err_num);
            return (DW_DLV_ERROR);
        }
        /*  If there is some kind of padding at the end of the section,
            as emitted by some compilers, skip over that padding and
            simply ignore the bytes thus passed-over.  With most
            compilers, pubnames_like_ptr == pubnames_ptr_past_end_cu at
            this point */
        pubnames_like_ptr = pubnames_ptr_past_end_cu;

    } while (pubnames_like_ptr < (section_data_ptr + section_length));

    /* Points to contiguous block of Dwarf_Global's. */
    ret_globals = (Dwarf_Global *)
        _dwarf_get_alloc(dbg, DW_DLA_LIST, global_count);
    if (ret_globals == NULL) {
        _dwarf_error(dbg, error, DW_DLE_ALLOC_FAIL);
        return (DW_DLV_ERROR);
    }

    /*  Store pointers to Dwarf_Global_s structs in contiguous block,
        and deallocate the chain. */
    curr_chain = head_chain;
    for (i = 0; i < global_count; i++) {
        *(ret_globals + i) = curr_chain->ch_item;
        prev_chain = curr_chain;
        curr_chain = curr_chain->ch_next;
        dwarf_dealloc(dbg, prev_chain, DW_DLA_CHAIN);
    }

    *globals = ret_globals;
    *return_count = (Dwarf_Signed) global_count;
    return DW_DLV_OK;
}


/*  Given a pubnames entry (or other like section entry)
    return thru the ret_name pointer
    a pointer to the string which is the entry name.  */
int
dwarf_globname(Dwarf_Global glob, char **ret_name, Dwarf_Error * error)
{
    if (glob == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_NULL);
        return (DW_DLV_ERROR);
    }

    *ret_name = (char *) (glob->gl_name);
    return DW_DLV_OK;
}


/*  Given a pubnames entry (or other like section entry)
    return thru the ret_off pointer the
    global offset of the DIE for this entry.
    The global offset is the offset within the .debug_info
    section as a whole.  */
int
dwarf_global_die_offset(Dwarf_Global global,
    Dwarf_Off * ret_off, Dwarf_Error * error)
{
    if (global == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_NULL);
        return (DW_DLV_ERROR);
    }

    if (global->gl_context == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_CONTEXT_NULL);
        return (DW_DLV_ERROR);
    }

    *ret_off = (global->gl_named_die_offset_within_cu +
        global->gl_context->pu_offset_of_cu_header);
    return DW_DLV_OK;
}

/*  Given a pubnames entry (or other like section entry)
    return thru the ret_off pointer the
    offset of the compilation unit header of the
    compilation unit the global is part of.

    In early versions of this, the value returned was
    the offset of the compilation unit die, and
    other cu-local die offsets were faked so adding this to
    such a cu-local offset got a true section offset.
    Now things do as they say (adding *cu_header_offset to
    a cu-local offset gets the section offset).  */
int
dwarf_global_cu_offset(Dwarf_Global global,
    Dwarf_Off * cu_header_offset,
    Dwarf_Error * error)
{
    Dwarf_Global_Context con = 0;

    if (global == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_NULL);
        return (DW_DLV_ERROR);
    }

    con = global->gl_context;

    if (con == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_CONTEXT_NULL);
        return (DW_DLV_ERROR);
    }

    /*  In early libdwarf, this incorrectly returned the offset of the
        CU DIE. Now correctly returns the header offset. */
    *cu_header_offset = con->pu_offset_of_cu_header;

    return DW_DLV_OK;
}

/*
  Give back the pubnames entry (or any other like section)
  name, symbol DIE offset, and the cu-DIE offset.

  Various errors are possible.

  The string pointer returned thru ret_name is not
  dwarf_get_alloc()ed, so no dwarf_dealloc()
  DW_DLA_STRING should be applied to it.

*/
int
dwarf_global_name_offsets(Dwarf_Global global,
    char **ret_name,
    Dwarf_Off * die_offset,
    Dwarf_Off * cu_die_offset,
    Dwarf_Error * error)
{
    Dwarf_Global_Context con = 0;
    Dwarf_Debug dbg = 0;
    Dwarf_Off off = 0;

    if (global == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_NULL);
        return (DW_DLV_ERROR);
    }

    con = global->gl_context;

    if (con == NULL) {
        _dwarf_error(NULL, error, DW_DLE_GLOBAL_CONTEXT_NULL);
        return (DW_DLV_ERROR);
    }

    off = con->pu_offset_of_cu_header;
    /*  The offset had better not be too close to the end. If it is,
        _dwarf_length_of_cu_header() will step off the end and therefore
        must not be used. 10 is a meaningless heuristic, but no CU
        header is that small so it is safe. An erroneous offset is due
        to a bug in the tool chain. A bug like this has been seen on
        IRIX with MIPSpro 7.3.1.3 and an executable > 2GB in size and
        with 2 million pubnames entries. */
#define MIN_CU_HDR_SIZE 10
    dbg = con->pu_dbg;
    if (dbg == NULL) {
        _dwarf_error(NULL, error, DW_DLE_DBG_NULL);
        return (DW_DLV_ERROR);
    }
    /* Cannot refer to debug_types */
    if (dbg->de_debug_info.dss_size &&
        ((off + MIN_CU_HDR_SIZE) >= dbg->de_debug_info.dss_size)) {
        _dwarf_error(NULL, error, DW_DLE_OFFSET_BAD);
        return (DW_DLV_ERROR);
    }
#undef MIN_CU_HDR_SIZE
    if (die_offset != NULL) {
        *die_offset = global->gl_named_die_offset_within_cu + off;
    }

    *ret_name = (char *) global->gl_name;

    if (cu_die_offset != NULL) {
        /* Globals cannot refer to debug_types */
        int cres = 0;
        Dwarf_Unsigned headerlen = 0;
        int res = _dwarf_load_debug_info(dbg, error);

        if (res != DW_DLV_OK) {
            return res;
        }
        /*  The offset had better not be too close to the end. If it is,
            _dwarf_length_of_cu_header() will step off the end and
            therefore must not be used. 10 is a meaningless heuristic,
            but no CU header is that small so it is safe. */
        /* Globals cannot refer to debug_types */
        if ((off + 10) >= dbg->de_debug_info.dss_size) {
            _dwarf_error(NULL, error, DW_DLE_OFFSET_BAD);
            return (DW_DLV_ERROR);
        }
        cres = _dwarf_length_of_cu_header(dbg, off,true,
            &headerlen,error);
        if(cres != DW_DLV_OK) {
            return cres;
        }
        *cu_die_offset = off + headerlen;
    }
    return DW_DLV_OK;
}

/*  We have the offset to a CU header.
    Return thru outFileOffset the offset of the CU DIE.

    New June, 2001.
    Used by SGI IRIX debuggers.
    No error used to be possible.
    As of May 2016 an error is possible if the DWARF is
    corrupted! (IRIX debuggers are no longer built ...)

    See also dwarf_CU_dieoffset_given_die().

    This is assumed to never apply to data in .debug_types, it
    only refers to .debug_info.

*/

/* ARGSUSED */
int
dwarf_get_cu_die_offset_given_cu_header_offset(Dwarf_Debug dbg,
    Dwarf_Off in_cu_header_offset,
    Dwarf_Off * out_cu_die_offset,
    UNUSEDARG Dwarf_Error * err)
{
    Dwarf_Off headerlen = 0;
    int cres = 0;

    cres = _dwarf_length_of_cu_header(dbg, in_cu_header_offset,true,
        &headerlen,err);
    if (cres != DW_DLV_OK) {
        return cres;
    }
    *out_cu_die_offset = in_cu_header_offset + headerlen;
    return DW_DLV_OK;
}

/*  The following version new in October 2011, does allow finding
    the offset if one knows whether debug_info or debug_types.

    However, it is not accurate in DWARF5 because
    there are two different header lengths (CU and TU)
    in DWARF5 .debug_info.  In that case, pretend
    that it's .debug_types (here) and pass is_info zero for
    a TU (as if it was in .debug_types).
    */
int
dwarf_get_cu_die_offset_given_cu_header_offset_b(Dwarf_Debug dbg,
    Dwarf_Off in_cu_header_offset,
    Dwarf_Bool is_info,
    Dwarf_Off * out_cu_die_offset,
    UNUSEDARG Dwarf_Error * err)
{
    Dwarf_Off headerlen = 0;
    int cres = 0;

    cres = _dwarf_length_of_cu_header(dbg, in_cu_header_offset,is_info,
        &headerlen,err);
    if (cres != DW_DLV_OK) {
        return cres;
    }
    *out_cu_die_offset = in_cu_header_offset + headerlen;
    return DW_DLV_OK;
}
/*  dwarf_CU_dieoffset_given_die returns
    the global debug_info section offset of the CU die
    that is the CU containing the given (passed-in) die.
    This information makes it possible for a consumer to
    find and print context information for any die.

    Use dwarf_offdie() passing in the offset this returns
    to get a die pointer to the CU die.  */
int
dwarf_CU_dieoffset_given_die(Dwarf_Die die,
    Dwarf_Off*       return_offset,
    Dwarf_Error*     error)
{
    Dwarf_Off  dieoff = 0;
    Dwarf_CU_Context cucontext = 0;

    CHECK_DIE(die, DW_DLV_ERROR);
    cucontext = die->di_cu_context;
    dieoff =  cucontext->cc_debug_offset;
    /*  The following call cannot fail, so no error check. */
    dwarf_get_cu_die_offset_given_cu_header_offset_b(
        cucontext->cc_dbg, dieoff,
        die->di_is_info, return_offset,error);
    return DW_DLV_OK;
}