[C++知识库]c语言开发postgres自定义函数

#include<stdio.h>
#include <stdlib.h>
#include<string.h>

#include "postgres.h"
#include "fmgr.h"


PG_MODULE_MAGIC;


PG_FUNCTION_INFO_V1(decrypt_data);


Datum decrypt_data(PG_FUNCTION_ARGS)
{
	text		*cipherdata = PG_GETARG_TEXT_P(0);
	text		*keyid = PG_GETARG_TEXT_P(1);
	text		*metadata = PG_GETARG_TEXT_P(2);
	text		*ivhex = PG_GETARG_TEXT_P(3);
	
	int32		cipherdata_len = VARSIZE(cipherdata) - VARHDRSZ;
	int32		keyid_len = VARSIZE(keyid) - VARHDRSZ;
	int32		metadata_len = VARSIZE(metadata) - VARHDRSZ;
	int32		ivhex_len = VARSIZE(ivhex) - VARHDRSZ;
	
	int32		new_text_size = cipherdata_len + VARHDRSZ;
	text		*new_text = (text *) palloc(new_text_size);
	
	SET_VARSIZE(new_text, new_text_size);

	char *ch_plain = NULL;
	unsigned char *ch_cipher = NULL;
	char ch_keyid[128] = {0};
	char ch_metadata[128] = {0};
	char ch_ivhex[128] = {0};

    char ch_end[1+1] = {0};
	int i_ret = 0;
	
	ch_plain = (char *)malloc(cipherdata_len + 64);
	if (ch_plain == NULL)
	{
		memcpy(VARDATA(new_text), VARDATA(cipherdata), cipherdata_len);
		PG_RETURN_TEXT_P(new_text);
	}
	ch_cipher = (char *)malloc(cipherdata_len + 64);
	if (ch_cipher == NULL)
	{
		free(ch_plain);
		memcpy(VARDATA(new_text), VARDATA(cipherdata), cipherdata_len);
		PG_RETURN_TEXT_P(new_text);
	}
	
	memset(ch_plain,0,cipherdata_len + 64);
	memset(ch_cipher,0,cipherdata_len + 64);
	
	memcpy(ch_cipher,VARDATA(cipherdata), cipherdata_len);
	memcpy(ch_keyid,VARDATA(keyid), keyid_len);
	memcpy(ch_metadata,VARDATA(metadata), metadata_len);
	memcpy(ch_ivhex,VARDATA(ivhex), ivhex_len);
	
	i_ret = Sm4GcmDecryptData(ch_cipher,ch_plain,ch_keyid,ch_metadata,ch_ivhex);
	if ( i_ret != 0 )
	{
		free(ch_plain);
		free(ch_cipher);
		memcpy(VARDATA(new_text), VARDATA(cipherdata), cipherdata_len);
		PG_RETURN_TEXT_P(new_text);
	}
	else
	{
		memcpy(VARDATA(new_text),ch_plain, strlen(ch_plain));
		memcpy(VARDATA(new_text) + strlen(ch_plain),ch_end, 1);
        free(ch_plain);
		free(ch_cipher);
		PG_RETURN_TEXT_P(new_text);
	}
}

编译生成动态库；

创建函数

create function decryptdata(varchar(256),varchar(64),varchar(64),varchar(64)) RETURNs VARCHAR(256)
AS 'libpostgresudf_Sdk.so', 'decrypt_data'
LANGUAGE C STRICT;

select name from AAA;

select decryptaoedata(name,'131798494913716','d4bcf051406dda1832b15a91fc652fb8','5b45197f108bb6ef18963796c394175b') from AAA;

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