static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)\n{\n    BIGNUM *kinv = NULL;\n    BIGNUM *m, *blind, *blindm, *tmp;\n    BN_CTX *ctx = NULL;\n    int reason = ERR_R_BN_LIB;\n    DSA_SIG *ret = NULL;\n    int rv = 0;\n    if (dsa->p == NULL || dsa->q == NULL || dsa->g == NULL) {\n        reason = DSA_R_MISSING_PARAMETERS;\n        goto err;\n    }\n    ret = DSA_SIG_new();\n    if (ret == NULL)\n        goto err;\n    ret->r = BN_new();\n    ret->s = BN_new();\n    if (ret->r == NULL || ret->s == NULL)\n        goto err;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n    m = BN_CTX_get(ctx);\n    blind = BN_CTX_get(ctx);\n    blindm = BN_CTX_get(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (tmp == NULL)\n        goto err;\n redo:\n    if (!dsa_sign_setup(dsa, ctx, &kinv, &ret->r, dgst, dlen))\n        goto err;\n    if (dlen > BN_num_bytes(dsa->q))\n        dlen = BN_num_bytes(dsa->q);\n    if (BN_bin2bn(dgst, dlen, m) == NULL)\n        goto err;\n    do {\n        if (!BN_priv_rand(blind, BN_num_bits(dsa->q) - 1,\n                          BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY))\n            goto err;\n    } while (BN_is_zero(blind));\n    BN_set_flags(blind, BN_FLG_CONSTTIME);\n    BN_set_flags(blindm, BN_FLG_CONSTTIME);\n    BN_set_flags(tmp, BN_FLG_CONSTTIME);\n    if (!BN_mod_mul(tmp, blind, dsa->priv_key, dsa->q, ctx))\n        goto err;\n    if (!BN_mod_mul(tmp, tmp, ret->r, dsa->q, ctx))\n        goto err;\n    if (!BN_mod_mul(blindm, blind, m, dsa->q, ctx))\n        goto err;\n    if (!BN_mod_add_quick(ret->s, tmp, blindm, dsa->q))\n        goto err;\n    if (!BN_mod_mul(ret->s, ret->s, kinv, dsa->q, ctx))\n        goto err;\n    if (BN_mod_inverse(blind, blind, dsa->q, ctx) == NULL)\n        goto err;\n    if (!BN_mod_mul(ret->s, ret->s, blind, dsa->q, ctx))\n        goto err;\n    if (BN_is_zero(ret->r) || BN_is_zero(ret->s))\n        goto redo;\n    rv = 1;\n err:\n    if (rv == 0) {\n        DSAerr(DSA_F_DSA_DO_SIGN, reason);\n        DSA_SIG_free(ret);\n        ret = NULL;\n    }\n    BN_CTX_free(ctx);\n    BN_clear_free(kinv);\n    return ret;\n}', 'static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,\n                          BIGNUM **kinvp, BIGNUM **rp,\n                          const unsigned char *dgst, int dlen)\n{\n    BN_CTX *ctx = NULL;\n    BIGNUM *k, *kinv = NULL, *r = *rp;\n    BIGNUM *l, *m;\n    int ret = 0;\n    int q_bits;\n    if (!dsa->p || !dsa->q || !dsa->g) {\n        DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS);\n        return 0;\n    }\n    k = BN_new();\n    l = BN_new();\n    m = BN_new();\n    if (k == NULL || l == NULL || m == NULL)\n        goto err;\n    if (ctx_in == NULL) {\n        if ((ctx = BN_CTX_new()) == NULL)\n            goto err;\n    } else\n        ctx = ctx_in;\n    q_bits = BN_num_bits(dsa->q);\n    if (!BN_set_bit(k, q_bits)\n        || !BN_set_bit(l, q_bits)\n        || !BN_set_bit(m, q_bits))\n        goto err;\n    do {\n        if (dgst != NULL) {\n            if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,\n                                       dlen, ctx))\n                goto err;\n        } else if (!BN_priv_rand_range(k, dsa->q))\n            goto err;\n    } while (BN_is_zero(k));\n    BN_set_flags(k, BN_FLG_CONSTTIME);\n    if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {\n        if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,\n                                    dsa->lock, dsa->p, ctx))\n            goto err;\n    }\n    if (!BN_add(l, k, dsa->q)\n        || !BN_add(m, l, dsa->q)\n        || !BN_copy(k, BN_num_bits(l) > q_bits ? l : m))\n        goto err;\n    if ((dsa)->meth->bn_mod_exp != NULL) {\n            if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, k, dsa->p, ctx,\n                                       dsa->method_mont_p))\n                goto err;\n    } else {\n            if (!BN_mod_exp_mont(r, dsa->g, k, dsa->p, ctx, dsa->method_mont_p))\n                goto err;\n    }\n    if (!BN_mod(r, r, dsa->q, ctx))\n        goto err;\n    if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL)\n        goto err;\n    BN_clear_free(*kinvp);\n    *kinvp = kinv;\n    kinv = NULL;\n    ret = 1;\n err:\n    if (!ret)\n        DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB);\n    if (ctx != ctx_in)\n        BN_CTX_free(ctx);\n    BN_clear_free(k);\n    BN_clear_free(l);\n    BN_clear_free(m);\n    return ret;\n}', 'int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    BIGNUM *t;\n    int ret = 0;\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(m);\n    BN_CTX_start(ctx);\n    if ((t = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (a == b) {\n        if (!BN_sqr(t, a, ctx))\n            goto err;\n    } else {\n        if (!BN_mul(t, a, b, ctx))\n            goto err;\n    }\n    if (!BN_nnmod(r, t, m, ctx))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("BN_CTX_start", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        ctx->err_stack++;\n    else if (!BN_STACK_push(&ctx->stack, ctx->used)) {\n        BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        ctx->err_stack++;\n    }\n    CTXDBG_EXIT(ctx);\n}', 'int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)\n{\n    int max, al;\n    int ret = 0;\n    BIGNUM *tmp, *rr;\n    bn_check_top(a);\n    al = a->top;\n    if (al <= 0) {\n        r->top = 0;\n        r->neg = 0;\n        return 1;\n    }\n    BN_CTX_start(ctx);\n    rr = (a != r) ? r : BN_CTX_get(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (rr == NULL || tmp == NULL)\n        goto err;\n    max = 2 * al;\n    if (bn_wexpand(rr, max) == NULL)\n        goto err;\n    if (al == 4) {\n#ifndef BN_SQR_COMBA\n        BN_ULONG t[8];\n        bn_sqr_normal(rr->d, a->d, 4, t);\n#else\n        bn_sqr_comba4(rr->d, a->d);\n#endif\n    } else if (al == 8) {\n#ifndef BN_SQR_COMBA\n        BN_ULONG t[16];\n        bn_sqr_normal(rr->d, a->d, 8, t);\n#else\n        bn_sqr_comba8(rr->d, a->d);\n#endif\n    } else {\n#if defined(BN_RECURSION)\n        if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) {\n            BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL * 2];\n            bn_sqr_normal(rr->d, a->d, al, t);\n        } else {\n            int j, k;\n            j = BN_num_bits_word((BN_ULONG)al);\n            j = 1 << (j - 1);\n            k = j + j;\n            if (al == j) {\n                if (bn_wexpand(tmp, k * 2) == NULL)\n                    goto err;\n                bn_sqr_recursive(rr->d, a->d, al, tmp->d);\n            } else {\n                if (bn_wexpand(tmp, max) == NULL)\n                    goto err;\n                bn_sqr_normal(rr->d, a->d, al, tmp->d);\n            }\n        }\n#else\n        if (bn_wexpand(tmp, max) == NULL)\n            goto err;\n        bn_sqr_normal(rr->d, a->d, al, tmp->d);\n#endif\n    }\n    rr->neg = 0;\n    if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l))\n        rr->top = max - 1;\n    else\n        rr->top = max;\n    if (r != rr && BN_copy(r, rr) == NULL)\n        goto err;\n    ret = 1;\n err:\n    bn_check_top(rr);\n    bn_check_top(tmp);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("BN_CTX_end", ctx);\n    if (ctx->err_stack)\n        ctx->err_stack--;\n    else {\n        unsigned int fp = BN_STACK_pop(&ctx->stack);\n        if (fp < ctx->used)\n            BN_POOL_release(&ctx->pool, ctx->used - fp);\n        ctx->used = fp;\n        ctx->too_many = 0;\n    }\n    CTXDBG_EXIT(ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']