ext/libelf/gelf_sym.c

/*-
 * Copyright (c) 2006 Joseph Koshy
 * 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 <limits.h>

#include <assert.h>
#include "gelf.h"

#include "_libelf.h"

GElf_Sym *
gelf_getsym(Elf_Data *d, int ndx, GElf_Sym *dst)
{
        int ec;
        Elf *e;
        Elf_Scn *scn;
        Elf32_Sym *sym32;
        Elf64_Sym *sym64;
        size_t msz;
        uint32_t sh_type;

        if (d == NULL || ndx < 0 || dst == NULL ||
            (scn = d->d_scn) == NULL ||
            (e = scn->s_elf) == NULL) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        ec = e->e_class;
        assert(ec == ELFCLASS32 || ec == ELFCLASS64);

        if (ec == ELFCLASS32)
                sh_type = scn->s_shdr.s_shdr32.sh_type;
        else
                sh_type = scn->s_shdr.s_shdr64.sh_type;

        if (_libelf_xlate_shtype(sh_type) != ELF_T_SYM) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        msz = _libelf_msize(ELF_T_SYM, ec, e->e_version);

        assert(msz > 0);

        if (msz * ndx >= d->d_size) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (NULL);
        }

        if (ec == ELFCLASS32) {

                sym32 = (Elf32_Sym *) d->d_buf + ndx;

                dst->st_name  = sym32->st_name;
                dst->st_value = (Elf64_Addr) sym32->st_value;
                dst->st_size  = (Elf64_Xword) sym32->st_size;
                dst->st_info  = ELF64_ST_INFO(ELF32_ST_BIND(sym32->st_info),
                    ELF32_ST_TYPE(sym32->st_info));
                dst->st_other = sym32->st_other;
                dst->st_shndx = sym32->st_shndx;
        } else {

                sym64 = (Elf64_Sym *) d->d_buf + ndx;

                *dst = *sym64;
        }

        return (dst);
}

int
gelf_update_sym(Elf_Data *d, int ndx, GElf_Sym *gs)
{
        int ec;
        Elf *e;
        Elf_Scn *scn;
        Elf32_Sym *sym32;
        Elf64_Sym *sym64;
        size_t msz;
        uint32_t sh_type;

        if (d == NULL || ndx < 0 || gs == NULL ||
            (scn = d->d_scn) == NULL ||
            (e = scn->s_elf) == NULL) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        ec = e->e_class;
        assert(ec == ELFCLASS32 || ec == ELFCLASS64);

        if (ec == ELFCLASS32)
                sh_type = scn->s_shdr.s_shdr32.sh_type;
        else
                sh_type = scn->s_shdr.s_shdr64.sh_type;

        if (_libelf_xlate_shtype(sh_type) != ELF_T_SYM) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        msz = _libelf_msize(ELF_T_SYM, ec, e->e_version);
        assert(msz > 0);

        if (msz * ndx >= d->d_size) {
                LIBELF_SET_ERROR(ARGUMENT, 0);
                return (0);
        }

        if (ec == ELFCLASS32) {
                sym32 = (Elf32_Sym *) d->d_buf + ndx;

                sym32->st_name  = gs->st_name;
                sym32->st_info  = gs->st_info;
                sym32->st_other = gs->st_other;
                sym32->st_shndx = gs->st_shndx;

                LIBELF_COPY_U32(sym32, gs, st_value);
                LIBELF_COPY_U32(sym32, gs, st_size);
        } else {
                sym64 = (Elf64_Sym *) d->d_buf + ndx;

                *sym64 = *gs;
        }

        return (1);
}