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E_BAD_ACCESS with palloc/pfree in base type

From: Michael Glaesemann <grzm(at)seespotcode(dot)net>
To: pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: E_BAD_ACCESS with palloc/pfree in base type
Date: 2007-08-31 05:31:43
Message-ID: 17443B5B-91F4-44CE-930A-0D68915D86FF@seespotcode.net (view raw or flat)
Thread:
Lists: pgsql-general
Hello all!

I'm working on a new base type. It's apparently installing fine via  
PG_XS. I'm using malloc and free for memory management within the  
module code.

x=# select '+1111'::x_type.x_type;
x_type
--------
+1111
(1 row)

x=# select '+111111111111'::x_type.x_type;
     x_type
---------------
+111111111111
(1 row)

It was recommended that I use palloc and pfree instead, so I replaced  
malloc/free with palloc/pfree. However, now I'm getting E_BAD_ACCESS  
errors (determined by stepping through the code with gdb) and  
backends dying on me on input.

x=# select '+1111'::x_type.x_type;
x_type
--------
+1111
(1 row)

x=# select '+111111111111'::x_type.x_type;
server closed the connection unexpectedly
         This probably means the server terminated abnormally
         before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>

I suspect it's something straightforward as not only is this the  
first base type I've worked on, I'm also not very experienced with C.  
It was suggested that perhaps I'm having a problem as I'm not  
defining a memory context. I thought that the memory context of the  
calling code would be used by default. Is this the case? I've  
included portions of the code below. I'd be happy to provide more  
details if it would help.

Any ideas as to what's going on? Any comments or suggestions very  
much appreciated.

Michael Glaesemann
grzm seespotcode net

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

--- x_type_base.c: X_TYPE_BASE_CHECK is not defined when compiling  
with USE_PGXS

#ifndef X_TYPE_BASE_CHECK
#define free pfree
#define malloc palloc
#endif

/*
* xTypeFromString takes a string as its second argument and
* assigns to its first argument the XType value represented
* by the string. If the assignment is successful, xTypeFromString
* returns true, and false otherwise.
*/
static inline
XTypeParseResult xTypeFromString (XType * aNumber, char * aString)
{
     char * theDigits = malloc(sizeof(XTypeMaximumStringLength));
     XTypeCountryCode * countryCode = malloc(sizeof(XTypeCountryCode));
     char * subscriberNumber = malloc(XTypeMaximumStringLength);
     XTypeParseResult xTypeParseResult;

     xTypeParseResult = parseXTypeString(aString, theDigits,
                                       countryCode, subscriberNumber);
     free(subscriberNumber);
     if (XTypeNoParseError == xTypeParseResult)
     {
         XType xTypeResult;
         char *cp;
         initializeXTypeWithCountryCode(&xTypeResult, countryCode);
         xTypeResult = (xTypeResult | strtoll(theDigits, &cp, 10));
         *aNumber = xTypeResult;
     }
     free(countryCode);
     free(theDigits);
     return xTypeParseResult;
}

--- x_type.c includes x_type_base.c

#define DatumGetXTypeP(X) ((XType *) DatumGetPointer(X))
#define XTypePGetDatum(X) PointerGetDatum(X)
#define PG_GETARG_X_TYPE_P(X) DatumGetXTypeP(PG_GETARG_DATUM(X))
#define PG_RETURN_X_TYPE_P(X) return XTypePGetDatum(X)
#define PG_GETARG_X_TYPE(X) PG_GETARG_INT64((int64) X)
#define PG_RETURN_X_TYPE(X) PG_RETURN_INT64((int64) X)

PG_FUNCTION_INFO_V1(x_type_in);
Datum
x_type_in(PG_FUNCTION_ARGS)
{
     char * theString = PG_GETARG_CSTRING(0);
     XType theNumber;
     XTypeParseResult parseResult = xTypeFromString(&theNumber,  
theString);
     if (XTypeNoParseError == parseResult)
     {
         XType * numberResult = palloc(sizeof(XType));
         *numberResult = theNumber;
         PG_RETURN_X_TYPE_P(numberResult);
     }
     else
         handleXTypeParseError(parseResult, theString);
}

PG_FUNCTION_INFO_V1(x_type_out);
Datum
x_type_out(PG_FUNCTION_ARGS)
{
     XType * theNumber = PG_GETARG_X_TYPE_P(0);
     char * theString = palloc(XTypeMaximumStringLength + 1);
     (void) stringFromXType(theString, theNumber,  
XTypeMaximumStringLength);
     PG_RETURN_CSTRING(theString);
}



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