xref: /illumos-gate/usr/src/lib/libdwarf/common/pro_reloc.c (revision 4d9fdb46)

/*
  Copyright (C) 2000,2004 Silicon Graphics, Inc.  All Rights Reserved.
  Portions Copyright 2008-2016 David Anderson, Inc. 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 "libdwarfdefs.h"
#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STDDEF_H
#include <stddef.h>
#endif /* HAVE_STDDEF_H */
#include "pro_incl.h"
#include "dwarf.h"
#include "libdwarf.h"
#include "pro_opaque.h"
#include "pro_error.h"
#include "pro_alloc.h"
#include "pro_reloc.h"


/*  Do initial alloc of newslots slots.
    Fails only if malloc fails.

    Supposed to be called before any relocs allocated.
    Ignored if after any allocated.

    Part of an optimization, so that for a known 'newslots'
    relocations count we can preallocate the right size block.
    Called from just 2 places.

    We use 'slots' so we don't have to do a new
    allocation for every relocation, just a new
    allocation every n slots. slots_in_block.

    returns DW_DLV_OK or  DW_DLV_ERROR
*/
int
_dwarf_pro_pre_alloc_specific_reloc_slots(Dwarf_P_Debug dbg,
    Dwarf_P_Per_Reloc_Sect prel,
    Dwarf_Unsigned newslots)
{
    unsigned long len = 0;
    struct Dwarf_P_Relocation_Block_s *data = 0;
    unsigned long slots_in_blk = (unsigned long) newslots;
    unsigned long rel_rec_size = dbg->de_relocation_record_size;

    if (prel->pr_first_block) {
        return DW_DLV_OK;       /* do nothing */
    }

    len = sizeof(struct Dwarf_P_Relocation_Block_s) +
        slots_in_blk * rel_rec_size;
    data = (struct Dwarf_P_Relocation_Block_s *)
        _dwarf_p_get_alloc(dbg, len);
    if (!data) {
        return DW_DLV_ERROR;
    }
    data->rb_slots_in_block = slots_in_blk;     /* could use default
        here, as fallback in case our origininal
        estimate wrong. When we call this we
        presumably know what we are doing, so
        keep this count for now */
    data->rb_next_slot_to_use = 0;
    data->rb_where_to_add_next =
        ((char *) data) + sizeof(struct Dwarf_P_Relocation_Block_s);
    data->rb_data = data->rb_where_to_add_next;

    prel->pr_first_block = data;
    prel->pr_last_block = data;
    prel->pr_block_count = 1;
    return DW_DLV_OK;
}


/*Do alloc of slots.
  Fails only if malloc fails.

  Only allocator used.

  returns DW_DLV_OK or  DW_DLV_ERROR
*/
int
_dwarf_pro_alloc_reloc_slots(Dwarf_P_Debug dbg, int rel_sec_index)
{
    unsigned long len = 0;
    struct Dwarf_P_Relocation_Block_s *data = 0;
    Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[rel_sec_index];
    unsigned long slots_in_blk = prel->pr_slots_per_block_to_alloc;
    unsigned long rel_rec_size = dbg->de_relocation_record_size;

    len = sizeof(struct Dwarf_P_Relocation_Block_s) +
        slots_in_blk * rel_rec_size;

    data = (struct Dwarf_P_Relocation_Block_s *)
        _dwarf_p_get_alloc(dbg, len);
    if (!data) {
        return DW_DLV_ERROR;
    }

    if (prel->pr_first_block) {
        prel->pr_last_block->rb_next = data;
        prel->pr_last_block = data;
        prel->pr_block_count += 1;
    } else {
        prel->pr_first_block = data;
        prel->pr_last_block = data;
        prel->pr_block_count = 1;
    }
    data->rb_slots_in_block = slots_in_blk;
    data->rb_next_slot_to_use = 0;
    data->rb_where_to_add_next =
        ((char *) data) + sizeof(struct Dwarf_P_Relocation_Block_s);
    data->rb_data = data->rb_where_to_add_next;
    return DW_DLV_OK;

}

/*  Reserve a slot. return DW_DLV_OK if succeeds.

    Return DW_DLV_ERROR if fails (malloc error).

    Use the relrec_to_fill to pass back a pointer to
    a slot space to use.  */
int
_dwarf_pro_reloc_get_a_slot(Dwarf_P_Debug dbg,
    int base_sec_index, void **relrec_to_fill)
{
    struct Dwarf_P_Relocation_Block_s *data = 0;
    Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[base_sec_index];
    unsigned long rel_rec_size = dbg->de_relocation_record_size;

    char *ret_addr = 0;

    data = prel->pr_last_block;
    if ((data == 0) ||
        (data->rb_next_slot_to_use >= data->rb_slots_in_block)) {
        int res;

        res = _dwarf_pro_alloc_reloc_slots(dbg, base_sec_index);
        if (res != DW_DLV_OK) {
            return res;
        }
    }

    data = prel->pr_last_block;
    /* now we have an empty slot */
    ret_addr = data->rb_where_to_add_next;
    data->rb_where_to_add_next += rel_rec_size;
    data->rb_next_slot_to_use += 1;
    prel->pr_reloc_total_count += 1;
    *relrec_to_fill = (void *) ret_addr;
    return DW_DLV_OK;

}

/*
    On success  returns count of
    .rel.* sections that are symbolic
    thru count_of_relocation_sections.

    On success, returns DW_DLV_OK.

    If this is not a 'symbolic' run, returns
    DW_DLV_NO_ENTRY.

    No errors are possible.
*/
/*ARGSUSED*/
int
dwarf_get_relocation_info_count(Dwarf_P_Debug dbg,
    Dwarf_Unsigned *
    count_of_relocation_sections,
    int *drd_buffer_version,
    UNUSEDARG Dwarf_Error * error)
{
    if (dbg->de_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
        int i = 0;
        unsigned int count = 0;

        for (i = 0; i < NUM_DEBUG_SECTIONS; ++i) {
            if (dbg->de_reloc_sect[i].pr_reloc_total_count > 0) {
                ++count;
            }
        }
        *count_of_relocation_sections = (Dwarf_Unsigned) count;
        *drd_buffer_version = DWARF_DRD_BUFFER_VERSION;
        return DW_DLV_OK;
    }
    /*  Reset to start at beginning of reloc groups. */
    dbg->de_reloc_next_to_return = 0;
    return DW_DLV_NO_ENTRY;
}

int
dwarf_get_relocation_info(Dwarf_P_Debug dbg,
    Dwarf_Signed * elf_section_index,
    Dwarf_Signed * elf_section_index_link,
    Dwarf_Unsigned * relocation_buffer_count,
    Dwarf_Relocation_Data * reldata_buffer,
    Dwarf_Error * error)
{
    int next = dbg->de_reloc_next_to_return;

    if (dbg->de_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
        int i = 0;

        for (i = next; i < NUM_DEBUG_SECTIONS; ++i) {
            /*  de_reloc_sect[] and de_elf_sects[] are
                in direct parallel. */
            Dwarf_P_Per_Reloc_Sect prel = &dbg->de_reloc_sect[i];
            int elf_sect_num =  dbg->de_elf_sects[i];

            if (prel->pr_reloc_total_count > 0) {
                /*  Set up 'next' for subsequent call to
                    dwarf_get_relocation_info(). */
                dbg->de_reloc_next_to_return = i + 1;

                /* ASSERT: prel->pr_block_count == 1 */
                *elf_section_index = prel->pr_sect_num_of_reloc_sect;

                /*  Elf sec num in generated elf */
                *elf_section_index_link = elf_sect_num;

                *relocation_buffer_count = prel->pr_reloc_total_count;
                *reldata_buffer = (Dwarf_Relocation_Data)
                    (prel->pr_first_block->rb_data);
                return DW_DLV_OK;
            }
        }
        DWARF_P_DBG_ERROR(dbg, DW_DLE_REL_ALLOC, DW_DLV_ERROR);
    }
    return DW_DLV_NO_ENTRY;
}