passing function's output into C function

[Kamil Kukura]

I have table with column of type "inet". Then I have my own function
resolveip(text). It works okay when I store IP addres into column typed
as text or varchar. But with type of inet I run into this problem:
select host(acc_ip), resolveip(host(acc_ip)) from access_test limit 15

host | resolveip
----------------+-----------------------------------
212.80.81.141 | Bad IP address: '212.80.81.141.'
212.80.81.141 | Bad IP address: '212.80.81.141'
212.80.81.141 | Bad IP address: '212.80.81.141'
212.80.81.141 | Bad IP address: '212.80.81.141'
80.139.171.208 | Bad IP address: '80.139.171.208*'
212.80.81.141 | Bad IP address: '212.80.81.1418'
212.80.81.141 | Bad IP address: '212.80.81.1418'
211.22.169.82 | Bad IP address: '211.22.169.828'
81.0.234.52 |
62.24.89.106 | Bad IP address: '62.24.89.106`'
81.0.234.52 | Bad IP address: '81.0.234.526'
212.80.81.141 | Bad IP address: '212.80.81.1415'
62.84.131.161 | Bad IP address: '62.84.131.1615'
212.80.81.141 | Bad IP address: '212.80.81.1415'
195.122.204.15 | e0-a11.b1.lan.prg.vol.cz

Is there something I'm missing when data are passed from function to
function?

--
Kamil Kukura

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[Joe Conway]

Kamil Kukura wrote:

Is there something I'm missing when data are passed from function to
function?

It is difficult to know what you might be missing when you haven't shown
us the function. Post the code.

Joe
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[Tom Lane]

Kamil Kukura <ka**@volny.cz> writes:

Is there something I'm missing when data are passed from function to
function?

I get the impression your function is expecting the contents of a text
datum to be null-terminated. It's not.

regards, tom lane

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[Kamil Kukura]

It was problem with allocating needed space, now it's okay. Anyway, the
code of function is being attached..

--
Kamil Kukura

#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>

#include "postgres.h"
#include "fmgr.h"
#include "utils/palloc.h"
text *create_text(char *data) {
unsigned long r_size;
text *result;

r_size = strlen(data);
result = palloc(r_size + VARHDRSZ);
VARATT_SIZEP(result) = r_size + VARHDRSZ;
memcpy(VARDATA(result), data, r_size);
return(result);
}
PG_FUNCTION_INFO_V1(resolveip);

Datum resolveip(PG_FUNCTION_ARGS) {
struct hostent *host;
struct in_addr addr;
text *ipaddress = (text *)PG_GETARG_TEXT_P(0);
const char *bad_ip_txt = "Bad IP address: '";
char *message;

unsigned long r_size, a_size = VARSIZE(ipaddress) - VARHDRSZ;
char *saddress = (char *)palloc(a_size + 1);

memcpy(saddress, VARDATA(ipaddress), a_size);
saddress[a_size] = 0; /* terminate string */

if (! inet_aton(saddress, &addr)) {
message = palloc(strlen(bad_ip_txt) + a_size + 2);
message[0] = 0;
strcat(message, bad_ip_txt);
strcat(message, saddress);
strcat(message, "'");

PG_RETURN_TEXT_P(create_text(message));
}
host = gethostbyaddr(&addr, sizeof addr, AF_INET);

if (! host) {
PG_RETURN_NULL();
}

PG_RETURN_TEXT_P(create_text(host->h_name));
}
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