Re: Problems with a C function, pg_uname(), and String concatenation.

[Rafael Martinez <r.m.guerrero@xxxxxxxxxxx>]

Pavel Stehule wrote:
> 2008/7/1 Rafael Martinez <r.m.guerrero@xxxxxxxxxxx>:
> > Pavel Stehule wrote:
> > > hello
> > > try
> > >
> > >
> > > memcpy(VARDATA(result),uname_pointer.release,strlen(uname_pointer.release));
> > > SET_VARSIZE(result, strlen(uname_pointer.release) + VARHDRSZ);
> > [.........]
> >
> > This a 8.2.x system. SET_VARSIZE is not available.
>
> VARATT_SIZEP(result) = strlen(uname_pointer.release) + VARHDRSZ;

Hello and thank you for your help.

Everything works perfect now with the new version of the function. Here 
it is just in case somebody wants to use it:

-------------------------------------------------------
#include "postgres.h"
#include <string.h>
#include "fmgr.h"
#include <sys/utsname.h>


#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif


PG_FUNCTION_INFO_V1(pg_uname);

Datum
pg_uname(PG_FUNCTION_ARGS)
{
    text *argument = PG_GETARG_TEXT_P(0);
    size_t argumentlen = VARSIZE(argument)-VARHDRSZ;

    text *result = (text *) palloc(256);
    char *option = (char *) palloc(argumentlen+1);

    char sysname[] = "sysname";
    char nodename[] = "nodename";
    char release[] = "release";
    char version[] = "version";
    char machine[] = "machine";
    char null[] = "null";

    struct utsname uname_pointer;
    uname(&uname_pointer);

    memcpy(option,VARDATA(argument),argumentlen);
    option[argumentlen] = '\0';

    if (strcmp(option,sysname) == 0){
      VARATT_SIZEP(result) = strlen(uname_pointer.sysname) + VARHDRSZ;

memcpy(VARDATA(result),uname_pointer.sysname,strlen(uname_pointer.sysname));
    }
    else if (strcmp(option,nodename) == 0){
      VARATT_SIZEP(result) = strlen(uname_pointer.nodename) + VARHDRSZ;

memcpy(VARDATA(result),uname_pointer.nodename,strlen(uname_pointer.nodename));
    }
    else if (strcmp(option,release) == 0){
      VARATT_SIZEP(result) = strlen(uname_pointer.release) + VARHDRSZ;

memcpy(VARDATA(result),uname_pointer.release,strlen(uname_pointer.release));
    }
    else if (strcmp(option,version) == 0){
      VARATT_SIZEP(result) = strlen(uname_pointer.version) + VARHDRSZ;

memcpy(VARDATA(result),uname_pointer.version,strlen(uname_pointer.version));
    }
    else if (strcmp(option,machine) == 0){
      VARATT_SIZEP(result) = strlen(uname_pointer.machine) + VARHDRSZ;

memcpy(VARDATA(result),uname_pointer.machine,strlen(uname_pointer.machine));
    }
    else{
      memcpy(VARDATA(result),null,sizeof(null));
    }

    pfree(option);
    PG_RETURN_TEXT_P(result);
}

-------------------------------------------------------


--
 Rafael Martinez, <r.m.guerrero@xxxxxxxxxxx>
 Center for Information Technology Services
 University of Oslo, Norway

 PGP Public Key: http://folk.uio.no/rafael/