/*

 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include <errno.h>

#include "bio_local.h"

#include "internal/cryptlib.h"

#include <openssl/rand.h>

/*

 * BIO_put and BIO_get both add to the digest, BIO_gets returns the digest

 */

static int nbiof_write(BIO *h, const char *buf, int num);

static int nbiof_read(BIO *h, char *buf, int size);

static int nbiof_puts(BIO *h, const char *str);

static int nbiof_gets(BIO *h, char *str, int size);

static long nbiof_ctrl(BIO *h, int cmd, long arg1, void *arg2);

static int nbiof_new(BIO *h);

static int nbiof_free(BIO *data);

static long nbiof_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);

typedef struct nbio_test_st {

    /* only set if we sent a 'should retry' error */

    int lrn;

    int lwn;

} NBIO_TEST;

static const BIO_METHOD methods_nbiof = {

    BIO_TYPE_NBIO_TEST,

    "non-blocking IO test filter",

    bwrite_conv,

    nbiof_write,

    bread_conv,

    nbiof_read,

    nbiof_puts,

    nbiof_gets,

    nbiof_ctrl,

    nbiof_new,

    nbiof_free,

    nbiof_callback_ctrl,

};

const BIO_METHOD *BIO_f_nbio_test(void)

{

    return &methods_nbiof;

}

static int nbiof_new(BIO *bi)

{

    NBIO_TEST *nt;

    if ((nt = OPENSSL_zalloc(sizeof(*nt))) == NULL) {

        ERR_raise(ERR_LIB_BIO, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    nt->lrn = -1;

    nt->lwn = -1;

    bi->ptr = (char *)nt;

    bi->init = 1;

    return 1;

}

static int nbiof_free(BIO *a)

{

    if (a == NULL)

        return 0;

    OPENSSL_free(a->ptr);

    a->ptr = NULL;

    a->init = 0;

    a->flags = 0;

    return 1;

}

static int nbiof_read(BIO *b, char *out, int outl)

{

    int ret = 0;

    int num;

    unsigned char n;

    if (out == NULL)

        return 0;

    if (b->next_bio == NULL)

        return 0;

    BIO_clear_retry_flags(b);

    if (RAND_priv_bytes(&n, 1) <= 0)

        return -1;

    num = (n & 0x07);

    if (outl > num)

        outl = num;

    if (num == 0) {

        ret = -1;

        BIO_set_retry_read(b);

    } else {

        ret = BIO_read(b->next_bio, out, outl);

        if (ret < 0)

            BIO_copy_next_retry(b);

    }

    return ret;

}

static int nbiof_write(BIO *b, const char *in, int inl)

{

    NBIO_TEST *nt;

    int ret = 0;

    int num;

    unsigned char n;

    if ((in == NULL) || (inl <= 0))

        return 0;

    if (b->next_bio == NULL)

        return 0;

    nt = (NBIO_TEST *)b->ptr;

    BIO_clear_retry_flags(b);

    if (nt->lwn > 0) {

        num = nt->lwn;

        nt->lwn = 0;

    } else {

        if (RAND_priv_bytes(&n, 1) <= 0)

            return -1;

        num = (n & 7);

    }

    if (inl > num)

        inl = num;

    if (num == 0) {

        ret = -1;

        BIO_set_retry_write(b);

    } else {

        ret = BIO_write(b->next_bio, in, inl);

        if (ret < 0) {

            BIO_copy_next_retry(b);

            nt->lwn = inl;

        }

    }

    return ret;

}

static long nbiof_ctrl(BIO *b, int cmd, long num, void *ptr)

{

    long ret;

    if (b->next_bio == NULL)

        return 0;

    switch (cmd) {

    case BIO_C_DO_STATE_MACHINE:

        BIO_clear_retry_flags(b);

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        BIO_copy_next_retry(b);

        break;

    case BIO_CTRL_DUP:

        ret = 0L;

        break;

    default:

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    }

    return ret;

}

static long nbiof_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)

{

    if (b->next_bio == NULL)

        return 0;

    return BIO_callback_ctrl(b->next_bio, cmd, fp);

}

static int nbiof_gets(BIO *bp, char *buf, int size)

{

    if (bp->next_bio == NULL)

        return 0;

    return BIO_gets(bp->next_bio, buf, size);

}

static int nbiof_puts(BIO *bp, const char *str)

{

    if (bp->next_bio == NULL)

        return 0;

    return BIO_puts(bp->next_bio, str);

}