/*

 * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 <string.h>

#include <errno.h>

#include <openssl/bio.h>

#include "apps.h"

static int prefix_write(BIO *b, const char *out, size_t outl,

                        size_t *numwritten);

static int prefix_read(BIO *b, char *buf, size_t size, size_t *numread);

static int prefix_puts(BIO *b, const char *str);

static int prefix_gets(BIO *b, char *str, int size);

static long prefix_ctrl(BIO *b, int cmd, long arg1, void *arg2);

static int prefix_create(BIO *b);

static int prefix_destroy(BIO *b);

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

static BIO_METHOD *prefix_meth = NULL;

BIO_METHOD *apps_bf_prefix(void)

{

    if (prefix_meth == NULL) {

        if ((prefix_meth =

             BIO_meth_new(BIO_TYPE_FILTER, "Prefix filter")) == NULL

            || !BIO_meth_set_create(prefix_meth, prefix_create)

            || !BIO_meth_set_destroy(prefix_meth, prefix_destroy)

            || !BIO_meth_set_write_ex(prefix_meth, prefix_write)

            || !BIO_meth_set_read_ex(prefix_meth, prefix_read)

            || !BIO_meth_set_puts(prefix_meth, prefix_puts)

            || !BIO_meth_set_gets(prefix_meth, prefix_gets)

            || !BIO_meth_set_ctrl(prefix_meth, prefix_ctrl)

            || !BIO_meth_set_callback_ctrl(prefix_meth, prefix_callback_ctrl)) {

            BIO_meth_free(prefix_meth);

            prefix_meth = NULL;

        }

    }

    return prefix_meth;

}

typedef struct prefix_ctx_st {

    char *prefix;

    int linestart;               /* flag to indicate we're at the line start */

} PREFIX_CTX;

static int prefix_create(BIO *b)

{

    PREFIX_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));

    if (ctx == NULL)

        return 0;

    ctx->prefix = NULL;

    ctx->linestart = 1;

    BIO_set_data(b, ctx);

    BIO_set_init(b, 1);

    return 1;

}

static int prefix_destroy(BIO *b)

{

    PREFIX_CTX *ctx = BIO_get_data(b);

    OPENSSL_free(ctx->prefix);

    OPENSSL_free(ctx);

    return 1;

}

static int prefix_read(BIO *b, char *in, size_t size, size_t *numread)

{

    return BIO_read_ex(BIO_next(b), in, size, numread);

}

static int prefix_write(BIO *b, const char *out, size_t outl,

                        size_t *numwritten)

{

    PREFIX_CTX *ctx = BIO_get_data(b);

    if (ctx == NULL)

        return 0;

    /* If no prefix is set or if it's empty, we've got nothing to do here */

    if (ctx->prefix == NULL || *ctx->prefix == '\0') {

        /* We do note if what comes next will be a new line, though */

        if (outl > 0)

            ctx->linestart = (out[outl-1] == '\n');

        return BIO_write_ex(BIO_next(b), out, outl, numwritten);

    }

    *numwritten = 0;

    while (outl > 0) {

        size_t i;

        char c;

        /* If we know that we're at the start of the line, output the prefix */

        if (ctx->linestart) {

            size_t dontcare;

            if (!BIO_write_ex(BIO_next(b), ctx->prefix, strlen(ctx->prefix),

                              &dontcare))

                return 0;

            ctx->linestart = 0;

        }

        /* Now, go look for the next LF, or the end of the string */

        for (i = 0, c = '\0'; i < outl && (c = out[i]) != '\n'; i++)

            continue;

        if (c == '\n')

            i++;

        /* Output what we found so far */

        while (i > 0) {

            size_t num = 0;

            if (!BIO_write_ex(BIO_next(b), out, i, &num))

                return 0;

            out += num;

            outl -= num;

            *numwritten += num;

            i -= num;

        }

        /* If we found a LF, what follows is a new line, so take note */

        if (c == '\n')

            ctx->linestart = 1;

    }

    return 1;

}

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

{

    long ret = 0;

    switch (cmd) {

    case PREFIX_CTRL_SET_PREFIX:

        {

            PREFIX_CTX *ctx = BIO_get_data(b);

            if (ctx == NULL)

                break;

            OPENSSL_free(ctx->prefix);

            ctx->prefix = OPENSSL_strdup((const char *)ptr);

            ret = ctx->prefix != NULL;

        }

        break;

    default:

        if (BIO_next(b) != NULL)

            ret = BIO_ctrl(BIO_next(b), cmd, num, ptr);

        break;

    }

    return ret;

}

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

{

    return BIO_callback_ctrl(BIO_next(b), cmd, fp);

}

static int prefix_gets(BIO *b, char *buf, int size)

{

    return BIO_gets(BIO_next(b), buf, size);

}

static int prefix_puts(BIO *b, const char *str)

{

    return BIO_write(b, str, strlen(str));

}