/*      $NetBSD: symver.c,v 1.4 2013/05/09 15:38:14 christos Exp $      */

/*-
 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
 * 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 ``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 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.
 *
 * $FreeBSD: head/libexec/rtld-elf/rtld.c 220004 2011-03-25 18:23:10Z avg $
 */

/*-
 * Copyright (c) 2011 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by NONAKA Kimihiro.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <sys/cdefs.h>
__RCSID("$NetBSD: symver.c,v 1.4 2013/05/09 15:38:14 christos Exp $");

#include <sys/param.h>
#include <sys/exec_elf.h>
#include <string.h>

#include "debug.h"
#include "rtld.h"

void
_rtld_object_add_name(Obj_Entry *obj, const char *name)
{
    Name_Entry *entry;
    size_t len;

    len = strlen(name);
    entry = xmalloc(sizeof(Name_Entry) + len);

    if (entry != NULL) {
        strcpy(entry->name, name);
        SIMPLEQ_INSERT_TAIL(&obj->names, entry, link);
    }
}

int
_rtld_object_match_name(const Obj_Entry *obj, const char *name)
{
        Name_Entry *entry;

        SIMPLEQ_FOREACH(entry, &obj->names, link) {
                dbg(("name: %s, entry->name: %s", name, entry->name));
                if (strcmp(name, entry->name) == 0)
                        return 1;
        }
        return 0;
}

#ifdef RTLD_LOADER
static Obj_Entry *
locate_dependency(const Obj_Entry *obj, const char *name)
{
        const Objlist_Entry *entry;
        const Needed_Entry *needed;

        SIMPLEQ_FOREACH(entry, &_rtld_list_main, link) {
                if (_rtld_object_match_name(entry->obj, name))
                        return entry->obj;
        }

        for (needed = obj->needed; needed != NULL; needed = needed->next) {
                dbg(("needed: name: %s, str: %s", name,
                    &obj->strtab[needed->name]));
                if (strcmp(name, &obj->strtab[needed->name]) == 0 ||
                    (needed->obj != NULL && _rtld_object_match_name(needed->obj, name))) {
                        /*
                         * If there is DT_NEEDED for the name we are looking
                         * for, we are all set.  Note that object might not be
                         * found if dependency was not loaded yet, so the
                         * function can return NULL here.  This is expected
                         * and handled properly by the caller.
                         */
                        return needed->obj;
                }
        }

        _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
            obj->path, name);
        return NULL;
}

static int
check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
    const Elf_Vernaux *vna)
{
        const char *vername = &refobj->strtab[vna->vna_name];
        const char *depstrtab = depobj->strtab;
        const Elf_Verdef *vd = depobj->verdef;
        const Elf_Word hash = vna->vna_hash;

        if (vd == NULL) {
                _rtld_error("%s: version %s required by %s not defined",
                    depobj->path, vername, refobj->path);
                return -1;
        }

        for (;; vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {
                if (vd->vd_version != VER_DEF_CURRENT) {
                        _rtld_error(
                            "%s: Unsupported version %d of Elf_Verdef entry",
                            depobj->path, vd->vd_version);
                        return -1;
                }
                dbg(("hash: 0x%x, vd_hash: 0x%x", hash, vd->vd_hash));
                if (hash == vd->vd_hash) {
                        const Elf_Verdaux *vda = (const Elf_Verdaux *)
                            ((const char *)vd + vd->vd_aux);
                        dbg(("vername: %s, str: %s", vername,
                            &depstrtab[vda->vda_name]));
                        if (strcmp(vername, &depstrtab[vda->vda_name]) == 0)
                                return 0;
                }
                if (vd->vd_next == 0)
                        break;
        }
        if (vna->vna_flags & VER_FLG_WEAK)
                return 0;

        _rtld_error("%s: version %s required by %s not found", depobj->path,
            vername, refobj->path);
        return -1;
}

int
_rtld_verify_object_versions(Obj_Entry *obj)
{
        const char *strtab = obj->strtab;
        const Elf_Verneed *vn;
        const Elf_Vernaux *vna;
        const Elf_Verdef *vd;
        const Elf_Verdaux *vda;
        const Obj_Entry *depobj;
        int maxvertab, vernum;

        dbg(("obj->path: %s", obj->path));

        /*
         * If we don't have string table or objects that have their version
         * requirements already checked, we must be ok.
         */
        if (strtab == NULL || obj->vertab != NULL)
                return 0;

        maxvertab = 0;

        /*
         * Walk over defined and required version records and figure out
         * max index used by any of them. Do very basic sanity checking
         * while there.
         */
        for (vn = obj->verneed;
             vn != NULL;
             vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next)) {

                if (vn->vn_version != VER_NEED_CURRENT) {
                        _rtld_error(
                            "%s: Unsupported version %d of Elf_Verneed entry",
                            obj->path, vn->vn_version);
                        return -1;
                }

                dbg(("verneed: vn_file: %d, str: %s",
                    vn->vn_file, &strtab[vn->vn_file]));
                depobj = locate_dependency(obj, &strtab[vn->vn_file]);
                assert(depobj != NULL);

                for (vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
                     /*CONSTCOND*/1;
                     vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next)) {

                        if (check_object_provided_version(obj, depobj, vna) == -1)
                                return -1;

                        vernum = VER_NEED_IDX(vna->vna_other);
                        if (vernum > maxvertab)
                                maxvertab = vernum;

                        if (vna->vna_next == 0) {
                                /* No more symbols. */
                                break;
                        }
                }

                if (vn->vn_next == 0) {
                        /* No more dependencies. */
                        break;
                }
        }

        for (vd = obj->verdef;
             vd != NULL;
             vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {

                if (vd->vd_version != VER_DEF_CURRENT) {
                        _rtld_error(
                            "%s: Unsupported version %d of Elf_Verdef entry",
                            obj->path, vd->vd_version);
                        return -1;
                }

                dbg(("verdef: vn_ndx: 0x%x", vd->vd_ndx));
                vernum = VER_DEF_IDX(vd->vd_ndx);
                if (vernum > maxvertab)
                        maxvertab = vernum;

                if (vd->vd_next == 0) {
                        /* No more definitions. */
                        break;
                }
        }

        dbg(("maxvertab: %d", maxvertab));
        if (maxvertab == 0)
                return 0;

        /*
         * Store version information in array indexable by version index.
         * Verify that object version requirements are satisfied along the
         * way.
         */
        obj->vertabnum = maxvertab + 1;
        obj->vertab = (Ver_Entry *)xcalloc(obj->vertabnum * sizeof(Ver_Entry));

        for (vn = obj->verneed;
             vn != NULL;
             vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next)) {

                for (vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
                     /*CONSTCOND*/1;
                     vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next)) {

                        vernum = VER_NEED_IDX(vna->vna_other);
                        assert(vernum <= maxvertab);
                        obj->vertab[vernum].hash = vna->vna_hash;
                        obj->vertab[vernum].name = &strtab[vna->vna_name];
                        obj->vertab[vernum].file = &strtab[vn->vn_file];
                        obj->vertab[vernum].flags =
                            (vna->vna_other & VER_NEED_HIDDEN)
                              ? VER_INFO_HIDDEN : 0;
                        dbg(("verneed: vernum: %d, hash: 0x%x, name: %s, "
                            "file: %s, flags: 0x%x", vernum,
                            obj->vertab[vernum].hash, obj->vertab[vernum].name,
                            obj->vertab[vernum].file,
                            obj->vertab[vernum].flags));

                        if (vna->vna_next == 0) {
                                /* No more symbols. */
                                break;
                        }
                }
                if (vn->vn_next == 0) {
                        /* No more dependencies. */
                        break;
                }
        }

        for (vd = obj->verdef;
             vd != NULL;
             vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {

                if ((vd->vd_flags & VER_FLG_BASE) == 0) {
                        vernum = VER_DEF_IDX(vd->vd_ndx);
                        assert(vernum <= maxvertab);
                        vda = (const Elf_Verdaux *)
                            ((const char *)vd + vd->vd_aux);
                        obj->vertab[vernum].hash = vd->vd_hash;
                        obj->vertab[vernum].name = &strtab[vda->vda_name];
                        obj->vertab[vernum].file = NULL;
                        obj->vertab[vernum].flags = 0;
                        dbg(("verdef: vernum: %d, hash: 0x%x, name: %s",
                            vernum, obj->vertab[vernum].hash,
                            obj->vertab[vernum].name));
                }

                if (vd->vd_next == 0) {
                        /* No more definitions. */
                        break;
                }
        }

        return 0;
}
#endif