/*
  Copyright (C) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
  Portions Copyright (C) 2007-2020 David Anderson. All Rights Reserved.
  Portions Copyright 2012 SN Systems Ltd. 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 <limits.h> /* ULONG_MAX */
#include <string.h> /* memcpy() strlen() */

#if defined(_WIN32) && defined(HAVE_STDAFX_H)
#include "stdafx.h"
#endif /* HAVE_STDAFX_H */

#include "dwarf.h"
#include "libdwarf.h"
#include "libdwarf_private.h"
#include "dwarf_base_types.h"
#include "dwarf_safe_strcpy.h"
#include "dwarf_opaque.h"
#include "dwarf_alloc.h"
#include "dwarf_error.h"
#include "dwarf_util.h"
#include "dwarf_macro.h"

#define LEFTPAREN '('
#define RIGHTPAREN ')'
#define SPACE ' '

/*  Given the dwarf macro string, return a pointer to
    the value.  Returns pointer to 0 byte at end of string
    if no value found (meaning the value is the empty string).

    Only understands well-formed dwarf macinfo strings.
*/
char *
dwarf_find_macro_value_start(char *str)
{
    char *lcp;
    int funclike = 0;

    for (lcp = str; *lcp; ++lcp) {
        switch (*lcp) {
        case LEFTPAREN:
            funclike = 1;
            break;
        case RIGHTPAREN:
            /*  lcp+1 must be a space, and following
                char is the value */
            return lcp + 2;
        case SPACE:
            /*  We allow extraneous spaces inside macro parameter **
                list, just in case... This is not really needed. */
            if (!funclike) {
                return lcp + 1;
            }
            break;
        default:
            break;
        }
    }
    /*  Never found value: returns pointer to the 0 byte at end of
        string. */
    return lcp;

}

/*
   Try to keep fileindex correct in every Macro_Details
   record by tracking file starts and ends.
   Uses high water mark: space reused, not freed.
   Presumption is that this makes sense for most uses.
   STARTERMAX is set so that the array need not be expanded for
   most files: it is the initial include file depth.
*/
struct macro_stack_s {
    Dwarf_Signed *st_base;
    long st_max;
    long st_next_to_use;
    int  st_was_fault;
};

static void _dwarf_reset_index_macro_stack(struct macro_stack_s *ms);
static void
free_macro_stack(Dwarf_Debug dbg, struct macro_stack_s *ms)
{
    dwarf_dealloc(dbg,ms->st_base,DW_DLA_STRING);
    _dwarf_reset_index_macro_stack(ms);
}

#define STARTERMAX 10
static void
_dwarf_reset_index_macro_stack(struct macro_stack_s *ms)
{
    ms->st_base = 0;
    ms->st_max = 0;
    ms->st_next_to_use = 0;
    ms->st_was_fault = 0;
}
static int
_dwarf_macro_stack_push_index(Dwarf_Debug dbg, Dwarf_Signed indx,
    struct macro_stack_s *ms)
{

    if (!ms->st_max || ms->st_next_to_use >= ms->st_max) {
        long new_size = ms->st_max;
        Dwarf_Signed *newbase = 0;

        if (!new_size) {
            new_size = STARTERMAX;
        }
        new_size = new_size * 2;
        newbase =
            (Dwarf_Signed *)_dwarf_get_alloc(dbg, DW_DLA_STRING,
                new_size * sizeof(Dwarf_Signed));
        if (!newbase) {
            /* just leave the old array in place */
            ms->st_was_fault = 1;
            return DW_DLV_ERROR;
        }
        if (ms->st_base) {
            memcpy(newbase, ms->st_base,
                ms->st_next_to_use * sizeof(*newbase));
            dwarf_dealloc(dbg, ms->st_base, DW_DLA_STRING);
        }
        ms->st_base = newbase;
        ms->st_max = new_size;
    }
    ms->st_base[ms->st_next_to_use] = indx;
    ++ms->st_next_to_use;
    return DW_DLV_OK;
}

static Dwarf_Signed
_dwarf_macro_stack_pop_index(struct macro_stack_s *ms)
{
    if (ms->st_was_fault) {
        return -1;
    }
    if (ms->st_next_to_use > 0) {
        ms->st_next_to_use--;
        return (ms->st_base[ms->st_next_to_use]);
    } else {
        ms->st_was_fault = 1;
    }
    return -1;
}

/*  Starting at macro_offset in .debug_macinfo,
    if maximum_count is 0, treat as if it is infinite.
    get macro data up thru
    maximum_count entries or the end of a compilation
    unit's entries (whichever comes first).

    .debug_macinfo never appears in a .dwp Package File.
    So offset adjustment for such is not needed.
*/

int
dwarf_get_macro_details(Dwarf_Debug dbg,
    Dwarf_Off macro_offset,
    Dwarf_Unsigned maximum_count,
    Dwarf_Signed * entry_count,
    Dwarf_Macro_Details ** details,
    Dwarf_Error * error)
{
    Dwarf_Small *macro_base = 0;
    Dwarf_Small *macro_end = 0;
    Dwarf_Small *pnext = 0;
    Dwarf_Unsigned endloc = 0;
    unsigned char uc = 0;
    unsigned long depth = 0;
        /* By section 6.3.2 Dwarf3 draft 8/9,
        the base file should appear as
        DW_MACINFO_start_file. See
        http://gcc.gnu.org/ml/gcc-bugs/2005-02/msg03442.html
        on "[Bug debug/20253] New: [3.4/4.0 regression]:
        Macro debug info broken due to lexer change" for how
        gcc is broken in some versions. We no longer use
        depth as a stopping point, it's not needed as a
        stopping point anyway.  */
    int res = 0;
    /* count space used by strings */
    unsigned long str_space = 0;
    int done = 0;
    unsigned long space_needed = 0;
    unsigned long space_used = 0;
    unsigned long string_offset = 0;
    Dwarf_Small *return_data = 0;
    Dwarf_Small *pdata = 0;
    unsigned long final_count = 0;
    Dwarf_Signed fileindex = -1;
    Dwarf_Small *latest_str_loc = 0;
    struct macro_stack_s msdata;

    unsigned long count = 0;
    unsigned long max_count = (unsigned long) maximum_count;
    _dwarf_reset_index_macro_stack(&msdata);
    if (!dbg || dbg->de_magic != DBG_IS_VALID) {
        _dwarf_error_string(NULL, error, DW_DLE_DBG_NULL,
            "DW_DLE_DBG_NULL: Either null or it contains"
            "a stale Dwarf_Debug pointer");
        free_macro_stack(dbg,&msdata);
        return DW_DLV_ERROR;
    }

    res = _dwarf_load_section(dbg, &dbg->de_debug_macinfo,error);
    if (res != DW_DLV_OK) {
        free_macro_stack(dbg,&msdata);
        return res;
    }
    if (!dbg->de_debug_abbrev.dss_size) {
        free_macro_stack(dbg,&msdata);
        return DW_DLV_NO_ENTRY;
    }

    macro_base = dbg->de_debug_macinfo.dss_data;
    if (macro_base == NULL) {
        free_macro_stack(dbg,&msdata);
        return DW_DLV_NO_ENTRY;
    }
    if (macro_offset >= dbg->de_debug_macinfo.dss_size) {
        free_macro_stack(dbg,&msdata);
        return DW_DLV_NO_ENTRY;
    }
    macro_end = macro_base + dbg->de_debug_macinfo.dss_size;
    /*   FIXME debugfission is NOT handled here.  */

    pnext = macro_base + macro_offset;
    if (maximum_count == 0) {
        max_count = ULONG_MAX;
    }

    /* how many entries and how much space will they take? */
    endloc = (pnext - macro_base);
    if (endloc >= dbg->de_debug_macinfo.dss_size) {
        if (endloc == dbg->de_debug_macinfo.dss_size) {
            /* normal: found last entry */
            free_macro_stack(dbg,&msdata);
            return DW_DLV_NO_ENTRY;
        }
        _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_LENGTH_BAD);
        free_macro_stack(dbg,&msdata);
        return DW_DLV_ERROR;
    }
    for (count = 0; !done && count < max_count; ++count) {
        unsigned long slen = 0;

        uc = *pnext;
        ++pnext;                /* get past the type code */
        switch (uc) {
        case DW_MACINFO_define:
        case DW_MACINFO_undef:
            /* line, string */
        case DW_MACINFO_vendor_ext:
            /* number, string */
            SKIP_LEB128_CK(pnext,dbg,error,
                macro_end);
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            res = _dwarf_check_string_valid(dbg,
                macro_base,pnext,macro_end,
                DW_DLE_MACINFO_STRING_BAD,error);
            if (res != DW_DLV_OK) {
                return res;
            }
            slen = strlen((char *) pnext) + 1;
            pnext += slen;
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            str_space += slen;
            break;
        case DW_MACINFO_start_file:
            /* line, file index */
            SKIP_LEB128_CK(pnext,dbg,error,
                macro_end);
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            SKIP_LEB128_CK(pnext,dbg,error,
                macro_end);
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            ++depth;
            break;

        case DW_MACINFO_end_file:
            if (--depth == 0) {
                /*  done = 1; no, do not stop here,
                    at least one gcc had
                    the wrong depth settings in the
                    gcc 3.4 timeframe. */
            }
            /* no string or number here */
            break;
        case 0:
            /* end of cu's entries */
            done = 1;
            break;
        default:
            free_macro_stack(dbg,&msdata);
            _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_INCONSISTENT);
            return DW_DLV_ERROR;
            /* bogus macinfo! */
        }

        endloc = (pnext - macro_base);
        if (endloc == dbg->de_debug_macinfo.dss_size) {
            done = 1;
        } else if (endloc > dbg->de_debug_macinfo.dss_size) {
            _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_LENGTH_BAD);
            free_macro_stack(dbg,&msdata);
            return DW_DLV_ERROR;
        }
    }
    /*  ASSERT: The above loop will never let us get here
        with count < 1. No need to test for a zero count.

        We have 'count' array entries to allocate and
        str_space bytes of string space to provide for. */

    string_offset = count * sizeof(Dwarf_Macro_Details);

    /* extra 2 not really needed */
    space_needed = string_offset + str_space + 2;
    space_used = 0;
    return_data = pdata = (Dwarf_Small *)_dwarf_get_alloc(
        dbg, DW_DLA_STRING, space_needed);
    latest_str_loc = pdata + string_offset;
    if (pdata == 0) {
        free_macro_stack(dbg,&msdata);
        _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_MALLOC_SPACE);
        return DW_DLV_ERROR;
    }
    pnext = macro_base + macro_offset;

    done = 0;

    /* A series ends with a type code of 0. */

    for (final_count = 0; !done && final_count < count;
        ++final_count) {
        unsigned long slen = 0;
        Dwarf_Unsigned v1 = 0;
        Dwarf_Macro_Details *pdmd = (Dwarf_Macro_Details *) (pdata +
            (final_count * sizeof (Dwarf_Macro_Details)));

        endloc = (pnext - macro_base);
        if (endloc > dbg->de_debug_macinfo.dss_size) {
            dwarf_dealloc(dbg,return_data,DW_DLA_STRING);
            free_macro_stack(dbg,&msdata);
            _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_LENGTH_BAD);
            return DW_DLV_ERROR;
        }
        uc = *pnext;
        pdmd->dmd_offset = (pnext - macro_base);
        pdmd->dmd_type = uc;
        pdmd->dmd_fileindex = fileindex;
        pdmd->dmd_lineno = 0;
        pdmd->dmd_macro = 0;
        ++pnext;                /* get past the type code */
        switch (uc) {
        case DW_MACINFO_define:
        case DW_MACINFO_undef:
            /* line, string */
        case DW_MACINFO_vendor_ext:
            /* number, string */
            res = _dwarf_leb128_uword_wrapper(dbg,&pnext,
                macro_end,&v1,error);
            if (res != DW_DLV_OK) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                return res;
            }
            pdmd->dmd_lineno = v1;

            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            res = _dwarf_check_string_valid(dbg,
                macro_base,pnext,macro_end,
                DW_DLE_MACINFO_STRING_BAD,error);
            if (res != DW_DLV_OK) {
                dwarf_dealloc(dbg,return_data,DW_DLA_STRING);
                return res;
            }
            slen = strlen((char *) pnext) + 1;

            _dwarf_safe_strcpy((char *)latest_str_loc,
                space_needed - space_used,
                (const char *)pnext,slen-1);
            pdmd->dmd_macro = (char *) latest_str_loc;
            latest_str_loc += slen;
            space_used +=slen;
            pnext += slen;
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            break;
        case DW_MACINFO_start_file:
            /* Line, file index */
            res = _dwarf_leb128_uword_wrapper(dbg,&pnext,
                macro_end,&v1,error);
            if (res != DW_DLV_OK) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                return res;
            }
            pdmd->dmd_lineno = v1;
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            res = _dwarf_leb128_uword_wrapper(dbg,&pnext,
                macro_end,&v1,error);
            if (res != DW_DLV_OK) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                return res;
            }
            pdmd->dmd_fileindex = v1;
            (void) _dwarf_macro_stack_push_index(dbg, fileindex,
                &msdata);
            /*  We ignore the error, we just let
                fileindex ** be -1 when
                we pop this one. */
            fileindex = v1;
            if (((Dwarf_Unsigned)(pnext - macro_base)) >=
                dbg->de_debug_macinfo.dss_size) {
                free_macro_stack(dbg,&msdata);
                dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
                _dwarf_error(dbg, error,
                    DW_DLE_DEBUG_MACRO_INCONSISTENT);
                return DW_DLV_ERROR;
            }
            break;

        case DW_MACINFO_end_file:
            fileindex = _dwarf_macro_stack_pop_index(&msdata);
            break;              /* no string or number here */
        case 0:
            /* Type code of 0 means the end of cu's entries. */
            done = 1;
            break;
        default:
            /* Bogus macinfo! */
            dwarf_dealloc(dbg, return_data, DW_DLA_STRING);
            free_macro_stack(dbg,&msdata);
            _dwarf_error(dbg, error, DW_DLE_DEBUG_MACRO_INCONSISTENT);
            return DW_DLV_ERROR;
        }
    }
    *entry_count = count;
    *details = (Dwarf_Macro_Details *) return_data;
    free_macro_stack(dbg,&msdata);
    return DW_DLV_OK;
}
