Re: Using substr with user defined types

Thus spake Tom Lane
> darcy(at)druid(dot)net (D'Arcy J.M. Cain) writes:
> > Any ideas?
>
> Not with that much info. Sooner or later you're going to have to
> show us your C code...

Oh, sure. I was going to submit it to contrib when it was finished and
as I said, the fprintf test I added pretty much assures me that it isn't
in the code but just in case I am wrong, here it is.

/*
* PostgreSQL type definitions for chkpass
* Written by D'Arcy J.M. Cain
* darcy(at)druid(dot)net
* http://www.druid.net/darcy/
*
* $Id$
* best viewed with tabs set to 4
*/

#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <postgres.h>
#include <utils/palloc.h>

/*
* This type encrypts it's input unless the first character is a colon.
* The output is the encrypted form with a leading colon. The output
* format is designed to allow dump and reload operations to work as
* expected without doing special tricks.
*/

/*
* This is the internal storage format for CHKPASSs.
* 15 is all I need but add a little buffer
*/

typedef struct chkpass
{
char password[16];
} chkpass;

/*
* Various forward declarations:
*/

chkpass *chkpass_in(char *str);
char *chkpass_out(chkpass * addr);
char *chkpass_rout(chkpass * addr);

/* Only equal or not equal make sense */
bool chkpass_eq(chkpass * a1, text * a2);
bool chkpass_ne(chkpass * a1, text * a2);

/* This function checks that the password is a good one
* It's just a placeholder for now */
static int
verify_pass(const char *str)
{
return 0;
}

/*
* CHKPASS reader.
*/
chkpass *
chkpass_in(char *str)
{
chkpass *result;
char mysalt[4];
static bool random_initialized = false;
static char salt_chars[] =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

/* special case to let us enter encrypted passwords */
if (*str == ':')
{
result = (chkpass *) palloc(sizeof(chkpass));
strncpy(result->password, str + 1, 13);
result->password[13] = 0;
return (result);
}

if (verify_pass(str) != 0)
{
elog(ERROR, "chkpass_in: purported CHKPASS \"%s\" is a weak password",
str);
return NULL;
}

result = (chkpass *) palloc(sizeof(chkpass));

if (!random_initialized)
{
srandom((unsigned int) time(NULL));
random_initialized = true;
}

mysalt[0] = salt_chars[random() & 0x3f];
mysalt[1] = salt_chars[random() & 0x3f];
mysalt[2] = 0; /* technically the terminator is not
* necessary but I like to play safe */
strcpy(result->password, crypt(str, mysalt));
return (result);
}

/*
* CHKPASS output function.
* Just like any string but we know it is max 15 (13 plus colon and terminator.)
*/

char *
chkpass_out(chkpass * password)
{
char *result;

if (password == NULL)
return (NULL);

if ((result = (char *) palloc(16)) != NULL)
{
result[0] = ':';
strcpy(result + 1, password->password);
}

return (result);
}

/*
* special output function that doesn't output the colon
*/

char *
chkpass_rout(chkpass *password)
{
char *result;

if (password == NULL)
return (NULL);

if ((result = (char *) palloc(16)) != NULL)
strcpy(result, password->password);

return (result);
}

/*
* Boolean tests
*/

bool
chkpass_eq(chkpass * a1, text *a2)
{
char str[10];
int sz = 8;

if (a2->vl_len < 8) sz = a2->vl_len;
if (!a1 || !a2) return 0;
strncpy(str, a2->vl_dat, sz);
str[sz] = 0;
return (strcmp(a1->password, crypt(str, a1->password)) == 0);
}

bool
chkpass_ne(chkpass * a1, text *a2)
{
char str[10];
int sz = 8;

if (!a1 || !a2) return 0;
if (a2->vl_len < 8) sz = a2->vl_len;
strncpy(str, a2->vl_dat, sz);
str[sz] = 0;
return (strcmp(a1->password, crypt(str, a1->password)) != 0);
}

--
D'Arcy J.M. Cain <darcy(at){druid|vex}.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.