/*      $NetBSD: libdwarf_info.c,v 1.5 2024/03/03 17:37:32 christos Exp $       */

/*-
* Copyright (c) 2007 John Birrell ([email protected])
* Copyright (c) 2010,2011,2014,2023 Kai Wang
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include "_libdwarf.h"

__RCSID("$NetBSD: libdwarf_info.c,v 1.5 2024/03/03 17:37:32 christos Exp $");
ELFTC_VCSID("Id: libdwarf_info.c 4013 2023-10-14 22:40:50Z kaiwang27");

int
_dwarf_info_first_cu(Dwarf_Debug dbg, Dwarf_Error *error)
{
       Dwarf_CU cu;
       int ret;

       assert(dbg->dbg_cu_current == NULL);
       cu = STAILQ_FIRST(&dbg->dbg_cu);
       if (cu != NULL) {
               dbg->dbg_cu_current = cu;
               return (DW_DLE_NONE);
       }

       if (dbg->dbg_info_loaded)
               return (DW_DLE_NO_ENTRY);

       dbg->dbg_info_off = 0;
       ret = _dwarf_info_load(dbg, 0, 1, error);
       if (ret != DW_DLE_NONE)
               return (ret);

       dbg->dbg_cu_current = STAILQ_FIRST(&dbg->dbg_cu);

       return (DW_DLE_NONE);
}

int
_dwarf_info_first_tu(Dwarf_Debug dbg, Dwarf_Error *error)
{
       Dwarf_CU tu;
       int ret;

       assert(dbg->dbg_tu_current == NULL);
       tu = STAILQ_FIRST(&dbg->dbg_tu);
       if (tu != NULL) {
               dbg->dbg_tu_current = tu;
               return (DW_DLE_NONE);
       }

       if (dbg->dbg_types_loaded)
               return (DW_DLE_NO_ENTRY);

       dbg->dbg_types_off = 0;
       ret = _dwarf_info_load(dbg, 0, 0, error);
       if (ret != DW_DLE_NONE)
               return (ret);

       dbg->dbg_tu_current = STAILQ_FIRST(&dbg->dbg_tu);

       return (DW_DLE_NONE);
}

int
_dwarf_info_next_cu(Dwarf_Debug dbg, Dwarf_Error *error)
{
       Dwarf_CU cu;
       int ret;

       assert(dbg->dbg_cu_current != NULL);
       cu = STAILQ_NEXT(dbg->dbg_cu_current, cu_next);
       if (cu != NULL) {
               dbg->dbg_cu_current = cu;
               return (DW_DLE_NONE);
       }

       if (dbg->dbg_info_loaded) {
               dbg->dbg_cu_current = NULL;
               return (DW_DLE_NO_ENTRY);
       }

       ret = _dwarf_info_load(dbg, 0, 1, error);
       if (ret != DW_DLE_NONE)
               return (ret);

       dbg->dbg_cu_current = STAILQ_NEXT(dbg->dbg_cu_current, cu_next);

       return (DW_DLE_NONE);
}

int
_dwarf_info_next_tu(Dwarf_Debug dbg, Dwarf_Error *error)
{
       Dwarf_CU cu;
       int ret;

       assert(dbg->dbg_tu_current != NULL);
       cu = STAILQ_NEXT(dbg->dbg_tu_current, cu_next);
       if (cu != NULL) {
               dbg->dbg_tu_current = cu;
               return (DW_DLE_NONE);
       }

       if (dbg->dbg_types_loaded) {
               dbg->dbg_tu_current = NULL;
               return (DW_DLE_NO_ENTRY);
       }

       ret = _dwarf_info_load(dbg, 0, 0, error);
       if (ret != DW_DLE_NONE)
               return (ret);

       dbg->dbg_tu_current = STAILQ_NEXT(dbg->dbg_tu_current, cu_next);

       return (DW_DLE_NONE);
}

int
_dwarf_info_load(Dwarf_Debug dbg, Dwarf_Bool load_all, Dwarf_Bool is_info,
   Dwarf_Error *error)
{
       Dwarf_CU cu;
       Dwarf_Section *ds;
       int dwarf_size, ret;
       uint64_t length;
       uint64_t next_offset;
       uint64_t offset;

       ret = DW_DLE_NONE;

       if (is_info) {
               if (dbg->dbg_info_loaded)
                       return (ret);
               offset = dbg->dbg_info_off;
               ds = dbg->dbg_info_sec;
               if (ds == NULL)
                       return (DW_DLE_NO_ENTRY);
       } else {
               if (dbg->dbg_types_loaded)
                       return (ret);
               offset = dbg->dbg_types_off;
               ds = dbg->dbg_types_sec;
               if (ds == NULL)
                       return (DW_DLE_NO_ENTRY);
       }

       while (offset < ds->ds_size) {
               if ((cu = calloc(1, sizeof(struct _Dwarf_CU))) == NULL) {
                       DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
                       return (DW_DLE_MEMORY);
               }

               cu->cu_dbg = dbg;
               cu->cu_is_info = is_info;
               cu->cu_offset = offset;

               length = dbg->read(ds->ds_data, &offset, 4);
               if (length == 0xffffffff) {
                       length = dbg->read(ds->ds_data, &offset, 8);
                       dwarf_size = 8;
               } else
                       dwarf_size = 4;
               cu->cu_dwarf_size = dwarf_size;

               /*
                * Check if there is enough ELF data for this CU. This assumes
                * that libelf gives us the entire section in one Elf_Data
                * object.
                */
               if (length > ds->ds_size - offset) {
                       free(cu);
                       DWARF_SET_ERROR(dbg, error, DW_DLE_CU_LENGTH_ERROR);
                       return (DW_DLE_CU_LENGTH_ERROR);
               }

               /* Compute the offset to the next compilation unit: */
               next_offset = offset + length;
               if (is_info)
                       dbg->dbg_info_off = next_offset;
               else
                       dbg->dbg_types_off = next_offset;

               /* Initialise the compilation unit. */
               cu->cu_length = length;
               cu->cu_length_size = (dwarf_size == 4 ? 4 : 12);
               cu->cu_version = dbg->read(ds->ds_data, &offset, 2);

               /* Verify the DWARF version is supported. */
               if (cu->cu_version < 2 || cu->cu_version > 5) {
                       DWARF_SET_ERROR(dbg, error, DW_DLE_VERSION_STAMP_ERROR);
                       ret = DW_DLE_VERSION_STAMP_ERROR;
                       break;
               }

               if (cu->cu_version == 5) {
                       /*
                        * DWARF5 has unit_type, abbrev_offset and pointer_size
                        * fields are reordered.
                        */
                       cu->cu_unit_type = dbg->read(ds->ds_data, &offset, 1);
                       cu->cu_pointer_size = dbg->read(ds->ds_data, &offset,
                           1);
                       cu->cu_abbrev_offset = dbg->read(ds->ds_data, &offset,
                           dwarf_size);
               } else {
                       /* DWARF4 or lower. */
                       cu->cu_unit_type = is_info ? DW_UT_compile : DW_UT_type;
                       cu->cu_abbrev_offset = dbg->read(ds->ds_data, &offset,
                           dwarf_size);
                       cu->cu_pointer_size = dbg->read(ds->ds_data, &offset,
                           1);
               }

               cu->cu_abbrev_offset_cur = cu->cu_abbrev_offset;
               cu->cu_next_offset = next_offset;

               /* DWARF5 Section 7.5.1.2 defines the dwo_id field. */
               if (cu->cu_unit_type == DW_UT_skeleton ||
                   cu->cu_unit_type == DW_UT_split_compile) {
                       /* TODO: the ID is implementation defined. */
                       cu->cu_dwo_id = dbg->read(ds->ds_data, &offset, 8);
               }

               /* .debug_types extra fields. */
               if (!is_info || cu->cu_unit_type == DW_UT_type ||
                   cu->cu_unit_type == DW_UT_split_type) {
                       memcpy(cu->cu_type_sig.signature,
                           (char *) ds->ds_data + offset, 8);
                       offset += 8;
                       cu->cu_type_offset = dbg->read(ds->ds_data, &offset,
                           dwarf_size);
               }

               /* Add the compilation unit to the list. */
               if (is_info)
                       STAILQ_INSERT_TAIL(&dbg->dbg_cu, cu, cu_next);
               else
                       STAILQ_INSERT_TAIL(&dbg->dbg_tu, cu, cu_next);

               cu->cu_1st_offset = offset;

               offset = next_offset;

               if (!load_all)
                       break;
       }

       if (is_info) {
               if ((Dwarf_Unsigned) dbg->dbg_info_off >= ds->ds_size)
                       dbg->dbg_info_loaded = 1;
       } else {
               if ((Dwarf_Unsigned) dbg->dbg_types_off >= ds->ds_size)
                       dbg->dbg_types_loaded = 1;
       }

       return (ret);
}

void
_dwarf_info_cleanup(Dwarf_Debug dbg)
{
       Dwarf_CU cu, tcu;

       assert(dbg != NULL && dbg->dbg_mode == DW_DLC_READ);

       STAILQ_FOREACH_SAFE(cu, &dbg->dbg_cu, cu_next, tcu) {
               STAILQ_REMOVE(&dbg->dbg_cu, cu, _Dwarf_CU, cu_next);
               _dwarf_abbrev_cleanup(cu);
               if (cu->cu_lineinfo != NULL) {
                       _dwarf_lineno_cleanup(cu->cu_lineinfo);
                       cu->cu_lineinfo = NULL;
               }
               free(cu);
       }

       _dwarf_type_unit_cleanup(dbg);
}

void
_dwarf_type_unit_cleanup(Dwarf_Debug dbg)
{
       Dwarf_CU cu, tcu;

       assert(dbg != NULL && dbg->dbg_mode == DW_DLC_READ);

       STAILQ_FOREACH_SAFE(cu, &dbg->dbg_tu, cu_next, tcu) {
               STAILQ_REMOVE(&dbg->dbg_tu, cu, _Dwarf_CU, cu_next);
               _dwarf_abbrev_cleanup(cu);
               free(cu);
       }
}

int
_dwarf_info_gen(Dwarf_P_Debug dbg, Dwarf_Error *error)
{
       Dwarf_P_Section ds;
       Dwarf_Rel_Section drs;
       Dwarf_Unsigned offset;
       Dwarf_CU cu;
       int ret;

       assert(dbg != NULL && dbg->write_alloc != NULL);

       if (dbg->dbgp_root_die == NULL)
               return (DW_DLE_NONE);

       /* Create the single CU for this debugging object. */
       if ((cu = calloc(1, sizeof(struct _Dwarf_CU))) == NULL) {
               DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
               return (DW_DLE_MEMORY);
       }
       cu->cu_dbg = dbg;
       cu->cu_version = 2;     /* DWARF2 */
       cu->cu_pointer_size = dbg->dbg_pointer_size;
       STAILQ_INSERT_TAIL(&dbg->dbg_cu, cu, cu_next);

       /* Create .debug_info section. */
       if ((ret = _dwarf_section_init(dbg, &dbg->dbgp_info, ".debug_info", 0,
           error)) != DW_DLE_NONE)
               goto gen_fail1;
       ds = dbg->dbgp_info;

       /* Create relocation section for .debug_init */
       if ((ret = _dwarf_reloc_section_init(dbg, &drs, ds, error)) !=
           DW_DLE_NONE)
               goto gen_fail0;

       /* Length placeholder. (We only use 32-bit DWARF format) */
       RCHECK(WRITE_VALUE(cu->cu_length, 4));

       /* Write CU version */
       RCHECK(WRITE_VALUE(cu->cu_version, 2));

       /*
        * Write abbrev offset. (always 0, we only support single CU)
        * Also generate a relocation entry for this offset.
        */
       RCHECK(_dwarf_reloc_entry_add(dbg, drs, ds, dwarf_drt_data_reloc, 4,
           ds->ds_size, 0, cu->cu_abbrev_offset, ".debug_abbrev", error));

       /* Pointer size. */
       RCHECK(WRITE_VALUE(cu->cu_pointer_size, 1));

       /* Transform the DIE(s) of this CU. */
       RCHECK(_dwarf_die_gen(dbg, cu, drs, error));

       /* Now we can fill in the length of this CU. */
       cu->cu_length = ds->ds_size - 4;
       offset = 0;
       dbg->write(ds->ds_data, &offset, cu->cu_length, 4);

       /* Inform application the creation of .debug_info ELF section. */
       RCHECK(_dwarf_section_callback(dbg, ds, SHT_PROGBITS, 0, 0, 0, error));

       /*
        * Inform application the creation of relocation section for
        * .debug_info.
        */
       RCHECK(_dwarf_reloc_section_finalize(dbg, drs, error));

       return (DW_DLE_NONE);

gen_fail:
       _dwarf_reloc_section_free(dbg, &drs);

gen_fail0:
       _dwarf_section_free(dbg, &dbg->dbgp_info);

gen_fail1:
       STAILQ_REMOVE(&dbg->dbg_cu, cu, _Dwarf_CU, cu_next);
       free(cu);

       return (ret);
}

void
_dwarf_info_pro_cleanup(Dwarf_P_Debug dbg)
{
       Dwarf_CU cu;

       assert(dbg != NULL && dbg->dbg_mode == DW_DLC_WRITE);

       cu = STAILQ_FIRST(&dbg->dbg_cu);
       if (cu != NULL) {
               STAILQ_REMOVE(&dbg->dbg_cu, cu, _Dwarf_CU, cu_next);
               _dwarf_abbrev_cleanup(cu);
               free(cu);
       }
}

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