eng_table.c

Go to the documentation of this file.

/* ====================================================================
 * 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include "cryptlib.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 = OPENSSL_malloc(sizeof(ENGINE_PILE));
            if(!fnd) goto end;
            fnd->uptodate = 1;
            fnd->nid = *nids;
            fnd->sk = sk_ENGINE_new_null();
            if(!fnd->sk)
                {
                OPENSSL_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))
                {
                ENGINEerr(ENGINE_F_ENGINE_TABLE_REGISTER,
                        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);
    OPENSSL_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);
    }