/*
 * pgcrypto.c
 *		Various cryptographic stuff for openGauss.
 *
 * Copyright (c) 2001 Marko Kreen
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * contrib/pgcrypto/pgcrypto.c
 */

#include "postgres.h"
#include "knl/knl_variable.h"

#include <ctype.h>

#include "parser/scansup.h"
#include "utils/builtins.h"

#include "px.h"
#include "px-crypt.h"
#include "pgcrypto.h"

PG_MODULE_MAGIC;

/* private stuff */

typedef int (*PFN)(const char* name, void** res);
static void* find_provider(text* name, PFN pf, char* desc, int silent);

/* SQL function: hash(bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_digest);

Datum pg_digest(PG_FUNCTION_ARGS)
{
    bytea* arg = NULL;
    text* name = NULL;
    unsigned len, hlen;
    PX_MD* md = NULL;
    bytea* res = NULL;

    name = PG_GETARG_TEXT_P(1);

    /* will give error if fails */
    md = (PX_MD*)find_provider(name, (PFN)px_find_digest, "Digest", 0);

    hlen = px_md_result_size(md);

    res = (text*)palloc(hlen + VARHDRSZ);
    SET_VARSIZE(res, hlen + VARHDRSZ);

    arg = PG_GETARG_BYTEA_P(0);
    len = VARSIZE(arg) - VARHDRSZ;

    px_md_update(md, (uint8*)VARDATA(arg), len);
    px_md_finish(md, (uint8*)VARDATA(res));
    px_md_free(md);

    PG_FREE_IF_COPY(arg, 0);
    PG_FREE_IF_COPY(name, 1);

    PG_RETURN_BYTEA_P(res);
}

/* SQL function: hmac(data:bytea, key:bytea, type:text) returns bytea */
PG_FUNCTION_INFO_V1(pg_hmac);

Datum pg_hmac(PG_FUNCTION_ARGS)
{
    bytea* arg = NULL;
    bytea* key = NULL;
    text* name = NULL;
    unsigned len, hlen, klen;
    PX_HMAC* h = NULL;
    bytea* res = NULL;

    name = PG_GETARG_TEXT_P(2);

    /* will give error if fails */
    h = (PX_HMAC*)find_provider(name, (PFN)px_find_hmac, "HMAC", 0);

    hlen = px_hmac_result_size(h);

    res = (text*)palloc(hlen + VARHDRSZ);
    SET_VARSIZE(res, hlen + VARHDRSZ);

    arg = PG_GETARG_BYTEA_P(0);
    key = PG_GETARG_BYTEA_P(1);
    len = VARSIZE(arg) - VARHDRSZ;
    klen = VARSIZE(key) - VARHDRSZ;

    px_hmac_init(h, (uint8*)VARDATA(key), klen);
    px_hmac_update(h, (uint8*)VARDATA(arg), len);
    px_hmac_finish(h, (uint8*)VARDATA(res));
    px_hmac_free(h);

    PG_FREE_IF_COPY(arg, 0);
    PG_FREE_IF_COPY(key, 1);
    PG_FREE_IF_COPY(name, 2);

    PG_RETURN_BYTEA_P(res);
}

/* SQL function: pg_gen_salt(text) returns text */
PG_FUNCTION_INFO_V1(pg_gen_salt);

Datum pg_gen_salt(PG_FUNCTION_ARGS)
{
    text* arg0 = PG_GETARG_TEXT_PP(0);
    int len;
    char buf[PX_MAX_SALT_LEN + 1];

    text_to_cstring_buffer(arg0, buf, sizeof(buf));
    len = px_gen_salt(buf, buf, 0);
    if (len < 0)
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("gen_salt: %s", px_strerror(len))));

    PG_FREE_IF_COPY(arg0, 0);

    PG_RETURN_TEXT_P(cstring_to_text_with_len(buf, len));
}

/* SQL function: pg_gen_salt(text, int4) returns text */
PG_FUNCTION_INFO_V1(pg_gen_salt_rounds);

Datum pg_gen_salt_rounds(PG_FUNCTION_ARGS)
{
    text* arg0 = PG_GETARG_TEXT_PP(0);
    int rounds = PG_GETARG_INT32(1);
    int len;
    char buf[PX_MAX_SALT_LEN + 1];

    text_to_cstring_buffer(arg0, buf, sizeof(buf));
    len = px_gen_salt(buf, buf, rounds);
    if (len < 0)
        ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("gen_salt: %s", px_strerror(len))));

    PG_FREE_IF_COPY(arg0, 0);

    PG_RETURN_TEXT_P(cstring_to_text_with_len(buf, len));
}

/* SQL function: pg_crypt(psw:text, salt:text) returns text */
PG_FUNCTION_INFO_V1(pg_crypt);

Datum pg_crypt(PG_FUNCTION_ARGS)
{
    text* arg0 = PG_GETARG_TEXT_PP(0);
    text* arg1 = PG_GETARG_TEXT_PP(1);
    char *buf0, *buf1, *cres, *resbuf;
    text* res = NULL;

    buf0 = text_to_cstring(arg0);
    buf1 = text_to_cstring(arg1);

    resbuf = (char*)palloc0(PX_MAX_CRYPT);

    cres = px_crypt(buf0, buf1, resbuf, PX_MAX_CRYPT);

    pfree(buf0);
    pfree(buf1);

    if (cres == NULL)
        ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("crypt(3) returned NULL")));

    res = cstring_to_text(cres);

    pfree(resbuf);

    PG_FREE_IF_COPY(arg0, 0);
    PG_FREE_IF_COPY(arg1, 1);

    PG_RETURN_TEXT_P(res);
}

/* SQL function: pg_encrypt(bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_encrypt);

Datum pg_encrypt(PG_FUNCTION_ARGS)
{
    int err;
    bytea *data, *key, *res;
    text* type = NULL;
    PX_Combo* c = NULL;
    unsigned dlen, klen, rlen;

    type = PG_GETARG_TEXT_P(2);
    c = (PX_Combo*)find_provider(type, (PFN)px_find_combo, "Cipher", 0);

    data = PG_GETARG_BYTEA_P(0);
    key = PG_GETARG_BYTEA_P(1);
    dlen = VARSIZE(data) - VARHDRSZ;
    klen = VARSIZE(key) - VARHDRSZ;

    rlen = px_combo_encrypt_len(c, dlen);
    res = (bytea*)palloc(VARHDRSZ + rlen);

    err = px_combo_init(c, (uint8*)VARDATA(key), klen, NULL, 0);
    if (!err)
        err = px_combo_encrypt(c, (uint8*)VARDATA(data), dlen, (uint8*)VARDATA(res), &rlen);
    px_combo_free(c);

    PG_FREE_IF_COPY(data, 0);
    PG_FREE_IF_COPY(key, 1);
    PG_FREE_IF_COPY(type, 2);

    if (err) {
        pfree(res);
        ereport(ERROR,
            (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("encrypt error: %s", px_strerror(err))));
    }

    SET_VARSIZE(res, VARHDRSZ + rlen);
    PG_RETURN_BYTEA_P(res);
}

/* SQL function: pg_decrypt(bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_decrypt);

Datum pg_decrypt(PG_FUNCTION_ARGS)
{
    int err;
    bytea *data, *key, *res;
    text* type = NULL;
    PX_Combo* c = NULL;
    unsigned dlen, klen, rlen;

    type = PG_GETARG_TEXT_P(2);
    c = (PX_Combo*)find_provider(type, (PFN)px_find_combo, "Cipher", 0);

    data = PG_GETARG_BYTEA_P(0);
    key = PG_GETARG_BYTEA_P(1);
    dlen = VARSIZE(data) - VARHDRSZ;
    klen = VARSIZE(key) - VARHDRSZ;

    rlen = px_combo_decrypt_len(c, dlen);
    res = (bytea*)palloc(VARHDRSZ + rlen);

    err = px_combo_init(c, (uint8*)VARDATA(key), klen, NULL, 0);
    if (!err)
        err = px_combo_decrypt(c, (uint8*)VARDATA(data), dlen, (uint8*)VARDATA(res), &rlen);

    px_combo_free(c);

    if (err)
        ereport(ERROR,
            (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("decrypt error: %s", px_strerror(err))));

    SET_VARSIZE(res, VARHDRSZ + rlen);

    PG_FREE_IF_COPY(data, 0);
    PG_FREE_IF_COPY(key, 1);
    PG_FREE_IF_COPY(type, 2);

    PG_RETURN_BYTEA_P(res);
}

/* SQL function: pg_encrypt_iv(bytea, bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_encrypt_iv);

Datum pg_encrypt_iv(PG_FUNCTION_ARGS)
{
    int err;
    bytea *data, *key, *iv, *res;
    text* type = NULL;
    PX_Combo* c = NULL;
    unsigned dlen, klen, ivlen, rlen;

    type = PG_GETARG_TEXT_P(3);
    c = (PX_Combo*)find_provider(type, (PFN)px_find_combo, "Cipher", 0);

    data = PG_GETARG_BYTEA_P(0);
    key = PG_GETARG_BYTEA_P(1);
    iv = PG_GETARG_BYTEA_P(2);
    dlen = VARSIZE(data) - VARHDRSZ;
    klen = VARSIZE(key) - VARHDRSZ;
    ivlen = VARSIZE(iv) - VARHDRSZ;

    rlen = px_combo_encrypt_len(c, dlen);
    res = (bytea*)palloc(VARHDRSZ + rlen);

    err = px_combo_init(c, (uint8*)VARDATA(key), klen, (uint8*)VARDATA(iv), ivlen);
    if (!err)
        err = px_combo_encrypt(c, (uint8*)VARDATA(data), dlen, (uint8*)VARDATA(res), &rlen);

    px_combo_free(c);

    if (err)
        ereport(ERROR,
            (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("encrypt_iv error: %s", px_strerror(err))));

    SET_VARSIZE(res, VARHDRSZ + rlen);

    PG_FREE_IF_COPY(data, 0);
    PG_FREE_IF_COPY(key, 1);
    PG_FREE_IF_COPY(iv, 2);
    PG_FREE_IF_COPY(type, 3);

    PG_RETURN_BYTEA_P(res);
}

/* SQL function: pg_decrypt_iv(bytea, bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_decrypt_iv);

Datum pg_decrypt_iv(PG_FUNCTION_ARGS)
{
    int err;
    bytea *data, *key, *iv, *res;
    text* type = NULL;
    PX_Combo* c = NULL;
    unsigned dlen, klen, rlen, ivlen;

    type = PG_GETARG_TEXT_P(3);
    c = (PX_Combo*)find_provider(type, (PFN)px_find_combo, "Cipher", 0);

    data = PG_GETARG_BYTEA_P(0);
    key = PG_GETARG_BYTEA_P(1);
    iv = PG_GETARG_BYTEA_P(2);
    dlen = VARSIZE(data) - VARHDRSZ;
    klen = VARSIZE(key) - VARHDRSZ;
    ivlen = VARSIZE(iv) - VARHDRSZ;

    rlen = px_combo_decrypt_len(c, dlen);
    res = (bytea*)palloc(VARHDRSZ + rlen);

    err = px_combo_init(c, (uint8*)VARDATA(key), klen, (uint8*)VARDATA(iv), ivlen);
    if (!err)
        err = px_combo_decrypt(c, (uint8*)VARDATA(data), dlen, (uint8*)VARDATA(res), &rlen);

    px_combo_free(c);

    if (err)
        ereport(ERROR,
            (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("decrypt_iv error: %s", px_strerror(err))));

    SET_VARSIZE(res, VARHDRSZ + rlen);

    PG_FREE_IF_COPY(data, 0);
    PG_FREE_IF_COPY(key, 1);
    PG_FREE_IF_COPY(iv, 2);
    PG_FREE_IF_COPY(type, 3);

    PG_RETURN_BYTEA_P(res);
}

/* SQL function: pg_random_bytes(int4) returns bytea */
PG_FUNCTION_INFO_V1(pg_random_bytes);

Datum pg_random_bytes(PG_FUNCTION_ARGS)
{
    int err;
    int len = PG_GETARG_INT32(0);
    bytea* res = NULL;

    if (len < 1 || len > 1024)
        ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION), errmsg("Length not in range")));

    res = (bytea*)palloc(VARHDRSZ + len);
    SET_VARSIZE(res, VARHDRSZ + len);

    /* generate result */
    err = px_get_random_bytes((uint8*)VARDATA(res), len);
    if (err < 0)
        ereport(ERROR,
            (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
                errmsg("Random generator error: %s", px_strerror(err))));

    PG_RETURN_BYTEA_P(res);
}

static void* find_provider(text* name, PFN provider_lookup, char* desc, int silent)
{
    void* res = NULL;
    char* buf = NULL;
    int err;

    buf = downcase_truncate_identifier(VARDATA(name), VARSIZE(name) - VARHDRSZ, false);

    err = provider_lookup(buf, &res);

    if (err && !silent)
        ereport(
            ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("Cannot use \"%s\": %s", buf, px_strerror(err))));

    pfree(buf);

    return err ? NULL : res;
}