Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres ASP ADO - Problem)

#1

"Dave Page" <dpage (AT) vale-housing (DOT) co.uk> writes:

Quote:

Forwarded to -bugs in case it gets missed.
This looks like it might be an issue to me, though I may well have
overlooked something in my brief look at the code.

There's nothing wrong with that code. The only modifiable values in the
record are the "val" pointers, which are handled correctly. See the
comment:

* PQconninfoOptions[] is a constant static array that we use to initialize
* a dynamically allocated working copy. All the "val" fields in
* PQconninfoOptions[] *must* be NULL. In a working copy, non-null "val"
* fields point to malloc'd strings that should be freed when the working
* array is freed (see PQconninfoFree).

regards, tom lane

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#2

Marko Ristola <Marko.Ristola (AT) kolumbus (DOT) fi> writes:

Quote:

I don't know the reason, but that seems to be the problem, that I have
found.

isql crashes under conninfo_parse() on line "free(buf)".

In my experience, this is probably a symptom of some code scribbling
past the end of a malloc'd chunk of memory. What is usually right after
the end of a malloc'd chunk is a portion of malloc's own data
structures, and clobbering that data structure is highly likely to
result in a crash in a later call to malloc, free, or related routines.

You might try running the code under something like Electric Fence.

regards, tom lane

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#3

=20

Quote:

-----Original Message-----
From: Tom Lane [mailto:tgl (AT) sss (DOT) pgh.pa.us]=20
Sent: 02 August 2005 00:36
To: Dave Page
Cc: pgsql-bugs (AT) postgresql (DOT) org; pgsql-odbc (AT) postgresql (DOT) org
Subject: Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres=20
ASP ADO - Problem)=20
=20
"Dave Page" <dpage (AT) vale-housing (DOT) co.uk> writes:
Forwarded to -bugs in case it gets missed.
This looks like it might be an issue to me, though I may well have
overlooked something in my brief look at the code.=20
=20
There's nothing wrong with that code. The only modifiable=20
values in the
record are the "val" pointers, which are handled correctly. See the
comment:
=20
* PQconninfoOptions[] is a constant static array that we use=20
to initialize
* a dynamically allocated working copy. All the "val" fields in
* PQconninfoOptions[] *must* be NULL. In a working=20
copy, non-null "val"
* fields point to malloc'd strings that should be freed when=20
the working
* array is freed (see PQconninfoFree).

Ahh, missed that. Thanks Tom.

Regards, Dave

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Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres ASP ADO - Problem)

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Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres ASP ADO - Problem) - 08-01-2005 , 06:36 PM

Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres ASP ADO - Problem) - 08-01-2005 , 06:51 PM

Re: [BUGS] Libpq free bug? (Was: [ODBC] IIS Postgres ASP ADO - Problem) - 08-02-2005 , 02:15 AM