/* $OpenBSD: eng_table.c,v 1.9 2017/01/29 17:49:23 beck Exp $ */
/* ====================================================================
 * Copyright (c) 2001 The OpenSSL Project.  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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/lhash.h>

#include "eng_int.h"

/* The type of the items in the table */
typedef struct st_engine_pile {
        /* The 'nid' of this algorithm/mode */
        int nid;
        /* ENGINEs that implement this algorithm/mode. */
        STACK_OF(ENGINE) *sk;
        /* The default ENGINE to perform this algorithm/mode. */
        ENGINE *funct;
        /* Zero if 'sk' is newer than the cached 'funct', non-zero otherwise */
        int uptodate;
} ENGINE_PILE;

DECLARE_LHASH_OF(ENGINE_PILE);

/* The type exposed in eng_int.h */
struct st_engine_table {
        LHASH_OF(ENGINE_PILE) piles;
}; /* ENGINE_TABLE */

typedef struct st_engine_pile_doall {
        engine_table_doall_cb *cb;
        void *arg;
} ENGINE_PILE_DOALL;

/* Global flags (ENGINE_TABLE_FLAG_***). */
static unsigned int table_flags = 0;

/* API function manipulating 'table_flags' */
unsigned int
ENGINE_get_table_flags(void)
{
        return table_flags;
}

void
ENGINE_set_table_flags(unsigned int flags)
{
        table_flags = flags;
}

/* Internal functions for the "piles" hash table */
static unsigned long
engine_pile_hash(const ENGINE_PILE *c)
{
        return c->nid;
}

static int
engine_pile_cmp(const ENGINE_PILE *a, const ENGINE_PILE *b)
{
        return a->nid - b->nid;
}
static IMPLEMENT_LHASH_HASH_FN(engine_pile, ENGINE_PILE)
static IMPLEMENT_LHASH_COMP_FN(engine_pile, ENGINE_PILE)

static int
int_table_check(ENGINE_TABLE **t, int create)
{
        LHASH_OF(ENGINE_PILE) *lh;

        if (*t)
                return 1;
        if (!create)
                return 0;
        if ((lh = lh_ENGINE_PILE_new()) == NULL)
                return 0;
        *t = (ENGINE_TABLE *)lh;
        return 1;
}

/* Privately exposed (via eng_int.h) functions for adding and/or removing
 * ENGINEs from the implementation table */
int
engine_table_register(ENGINE_TABLE **table, ENGINE_CLEANUP_CB *cleanup,
    ENGINE *e, const int *nids, int num_nids, int setdefault)
{
        int ret = 0, added = 0;
        ENGINE_PILE tmplate, *fnd;

        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        if (!(*table))
                added = 1;
        if (!int_table_check(table, 1))
                goto end;
        if (added)
                /* The cleanup callback needs to be added */
                engine_cleanup_add_first(cleanup);
        while (num_nids--) {
                tmplate.nid = *nids;
                fnd = lh_ENGINE_PILE_retrieve(&(*table)->piles, &tmplate);
                if (!fnd) {
                        fnd = malloc(sizeof(ENGINE_PILE));
                        if (!fnd)
                                goto end;
                        fnd->uptodate = 1;
                        fnd->nid = *nids;
                        fnd->sk = sk_ENGINE_new_null();
                        if (!fnd->sk) {
                                free(fnd);
                                goto end;
                        }
                        fnd->funct = NULL;
                        (void)lh_ENGINE_PILE_insert(&(*table)->piles, fnd);
                }
                /* A registration shouldn't add duplciate entries */
                (void)sk_ENGINE_delete_ptr(fnd->sk, e);
                /* if 'setdefault', this ENGINE goes to the head of the list */
                if (!sk_ENGINE_push(fnd->sk, e))
                        goto end;
                /* "touch" this ENGINE_PILE */
                fnd->uptodate = 0;
                if (setdefault) {
                        if (!engine_unlocked_init(e)) {
                                ENGINEerror(ENGINE_R_INIT_FAILED);
                                goto end;
                        }
                        if (fnd->funct)
                                engine_unlocked_finish(fnd->funct, 0);
                        fnd->funct = e;
                        fnd->uptodate = 1;
                }
                nids++;
        }
        ret = 1;
end:
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        return ret;
}

static void
int_unregister_cb_doall_arg(ENGINE_PILE *pile, ENGINE *e)
{
        int n;

        /* Iterate the 'c->sk' stack removing any occurance of 'e' */
        while ((n = sk_ENGINE_find(pile->sk, e)) >= 0) {
                (void)sk_ENGINE_delete(pile->sk, n);
                pile->uptodate = 0;
        }
        if (pile->funct == e) {
                engine_unlocked_finish(e, 0);
                pile->funct = NULL;
        }
}
static IMPLEMENT_LHASH_DOALL_ARG_FN(int_unregister_cb, ENGINE_PILE, ENGINE)

void
engine_table_unregister(ENGINE_TABLE **table, ENGINE *e)
{
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        if (int_table_check(table, 0))
                lh_ENGINE_PILE_doall_arg(&(*table)->piles,
                    LHASH_DOALL_ARG_FN(int_unregister_cb), ENGINE, e);
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
}

static void
int_cleanup_cb_doall(ENGINE_PILE *p)
{
        sk_ENGINE_free(p->sk);
        if (p->funct)
                engine_unlocked_finish(p->funct, 0);
        free(p);
}
static IMPLEMENT_LHASH_DOALL_FN(int_cleanup_cb, ENGINE_PILE)

void
engine_table_cleanup(ENGINE_TABLE **table)
{
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        if (*table) {
                lh_ENGINE_PILE_doall(&(*table)->piles,
                    LHASH_DOALL_FN(int_cleanup_cb));
                lh_ENGINE_PILE_free(&(*table)->piles);
                *table = NULL;
        }
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
}

/* return a functional reference for a given 'nid' */
#ifndef ENGINE_TABLE_DEBUG
ENGINE *
engine_table_select(ENGINE_TABLE **table, int nid)
#else
ENGINE *
engine_table_select_tmp(ENGINE_TABLE **table, int nid, const char *f, int l)
#endif
{
        ENGINE *ret = NULL;
        ENGINE_PILE tmplate, *fnd = NULL;
        int initres, loop = 0;

        if (!(*table)) {
#ifdef ENGINE_TABLE_DEBUG
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, nothing "
                    "registered!\n", f, l, nid);
#endif
                return NULL;
        }
        ERR_set_mark();
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        /* Check again inside the lock otherwise we could race against cleanup
         * operations. But don't worry about a fprintf(stderr). */
        if (!int_table_check(table, 0))
                goto end;
        tmplate.nid = nid;
        fnd = lh_ENGINE_PILE_retrieve(&(*table)->piles, &tmplate);
        if (!fnd)
                goto end;
        if (fnd->funct && engine_unlocked_init(fnd->funct)) {
#ifdef ENGINE_TABLE_DEBUG
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, using "
                    "ENGINE '%s' cached\n", f, l, nid, fnd->funct->id);
#endif
                ret = fnd->funct;
                goto end;
        }
        if (fnd->uptodate) {
                ret = fnd->funct;
                goto end;
        }
trynext:
        ret = sk_ENGINE_value(fnd->sk, loop++);
        if (!ret) {
#ifdef ENGINE_TABLE_DEBUG
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, no "
                    "registered implementations would initialise\n", f, l, nid);
#endif
                goto end;
        }
        /* Try to initialise the ENGINE? */
        if ((ret->funct_ref > 0) || !(table_flags & ENGINE_TABLE_FLAG_NOINIT))
                initres = engine_unlocked_init(ret);
        else
                initres = 0;
        if (initres) {
                /* Update 'funct' */
                if ((fnd->funct != ret) && engine_unlocked_init(ret)) {
                        /* If there was a previous default we release it. */
                        if (fnd->funct)
                                engine_unlocked_finish(fnd->funct, 0);
                        fnd->funct = ret;
#ifdef ENGINE_TABLE_DEBUG
                        fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, "
                            "setting default to '%s'\n", f, l, nid, ret->id);
#endif
                }
#ifdef ENGINE_TABLE_DEBUG
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, using "
                    "newly initialised '%s'\n", f, l, nid, ret->id);
#endif
                goto end;
        }
        goto trynext;
end:
        /* If it failed, it is unlikely to succeed again until some future
         * registrations have taken place. In all cases, we cache. */
        if (fnd)
                fnd->uptodate = 1;
#ifdef ENGINE_TABLE_DEBUG
        if (ret)
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, caching "
                    "ENGINE '%s'\n", f, l, nid, ret->id);
        else
                fprintf(stderr, "engine_table_dbg: %s:%d, nid=%d, caching "
                    "'no matching ENGINE'\n", f, l, nid);
#endif
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        /* Whatever happened, any failed init()s are not failures in this
         * context, so clear our error state. */
        ERR_pop_to_mark();
        return ret;
}

/* Table enumeration */

static void
int_cb_doall_arg(ENGINE_PILE *pile, ENGINE_PILE_DOALL *dall)
{
        dall->cb(pile->nid, pile->sk, pile->funct, dall->arg);
}
static IMPLEMENT_LHASH_DOALL_ARG_FN(int_cb, ENGINE_PILE, ENGINE_PILE_DOALL)

void
engine_table_doall(ENGINE_TABLE *table, engine_table_doall_cb *cb, void *arg)
{
        ENGINE_PILE_DOALL dall;

        dall.cb = cb;
        dall.arg = arg;
        lh_ENGINE_PILE_doall_arg(&table->piles, LHASH_DOALL_ARG_FN(int_cb),
            ENGINE_PILE_DOALL, &dall);
}