Thread: Segmentation fault with lo_export
Hello, this problem appeared quite frequently in the last two years: the libpq-function lo_export gives a segmentation fault. This happend with the current snapshot (I don't remember the date, it was begin of June, filesize: 3980592) on Linux-2.0.34. It worked with Postgresql-6.3.2. Edmund -- Edmund Mergl mailto:E.Mergl@bawue.de Im Haldenhau 9 http://www.bawue.de/~mergl 70565 Stuttgart fon: +49 711 747503 Germany
Edmund, has this been fixed? > Hello, > > this problem appeared quite frequently in the last two years: > the libpq-function lo_export gives a segmentation fault. > > This happend with the current snapshot (I don't remember the > date, it was begin of June, filesize: 3980592) on Linux-2.0.34. > It worked with Postgresql-6.3.2. > > Edmund > -- > Edmund Mergl mailto:E.Mergl@bawue.de > Im Haldenhau 9 http://www.bawue.de/~mergl > 70565 Stuttgart fon: +49 711 747503 > Germany > > -- Bruce Momjian | 830 Blythe Avenue maillist@candle.pha.pa.us | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (610) 353-9879(w) + Christ can be your backup. | (610) 853-3000(h)
Bruce Momjian wrote:
>
> Edmund, has this been fixed?
>
> > Hello,
> >
> > this problem appeared quite frequently in the last two years:
> > the libpq-function lo_export gives a segmentation fault.
> >
> > This happend with the current snapshot (I don't remember the
> > date, it was begin of June, filesize: 3980592) on Linux-2.0.34.
> > It worked with Postgresql-6.3.2.
> >
> > Edmund
Hi Bruce,
it looks like the last time I tested lo_export it worked
just by chance.
The bug seems to be in interfaces/libpq/fe-lobj.c line 424.
The two functions lo_import and lo_export are somehow
similar when exchanging the read/write for Unix file
and inv file. But whereas read() reads exactly BUFSIZ
bytes, lo_read() appends a '\0' after having read
BUFSIZ bytes. So line 424 should be:
char buf[LO_BUFSIZE+1];
instead of:
char buf[LO_BUFSIZE];
Could you please apply this bug-fix ?
Also the code example in the man page for
large-objects needs to be corrected.
I can't do it by myself because I am on
vacation on a Greek island, and the only
message I'm seeing frequently is
'modem hangup, no CARRIER' ...
thanks
Edmund
--
Edmund Mergl mailto:E.Mergl@bawue.de
Im Haldenhau 9 http://www.bawue.de/~mergl
70565 Stuttgart fon: +49 711 747503
Germany
> Hi Bruce, > > it looks like the last time I tested lo_export it worked > just by chance. > > The bug seems to be in interfaces/libpq/fe-lobj.c line 424. > The two functions lo_import and lo_export are somehow > similar when exchanging the read/write for Unix file > and inv file. But whereas read() reads exactly BUFSIZ > bytes, lo_read() appends a '\0' after having read > BUFSIZ bytes. So line 424 should be: > > char buf[LO_BUFSIZE+1]; > > instead of: > > char buf[LO_BUFSIZE]; > > Could you please apply this bug-fix ? > Also the code example in the man page for > large-objects needs to be corrected. > > I can't do it by myself because I am on > vacation on a Greek island, and the only > message I'm seeing frequently is > 'modem hangup, no CARRIER' ... I am going to fix lo_read(). I see no reason not to have it function like read(). -- Bruce Momjian | 830 Blythe Avenue maillist@candle.pha.pa.us | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (610) 353-9879(w) + Christ can be your backup. | (610) 853-3000(h)
> > Hi Bruce, > > > > it looks like the last time I tested lo_export it worked > > just by chance. > > > > The bug seems to be in interfaces/libpq/fe-lobj.c line 424. > > The two functions lo_import and lo_export are somehow > > similar when exchanging the read/write for Unix file > > and inv file. But whereas read() reads exactly BUFSIZ > > bytes, lo_read() appends a '\0' after having read > > BUFSIZ bytes. So line 424 should be: > > > > char buf[LO_BUFSIZE+1]; > > > > instead of: > > > > char buf[LO_BUFSIZE]; > > > > Could you please apply this bug-fix ? > > Also the code example in the man page for > > large-objects needs to be corrected. > > > > I can't do it by myself because I am on > > vacation on a Greek island, and the only > > message I'm seeing frequently is > > 'modem hangup, no CARRIER' ... > > I am going to fix lo_read(). I see no reason not to have it function > like read(). OK. It was actually libpq that was placing the NULL, through PQfn() and pqGetnchar(). Shouldn't have. Fixed now. -- Bruce Momjian | 830 Blythe Avenue maillist@candle.pha.pa.us | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (610) 353-9879(w) + Christ can be your backup. | (610) 853-3000(h)
> Hello, > > this problem appeared quite frequently in the last two years: > the libpq-function lo_export gives a segmentation fault. > > This happend with the current snapshot (I don't remember the > date, it was begin of June, filesize: 3980592) on Linux-2.0.34. > It worked with Postgresql-6.3.2. I suspect my large objects change have fix it. -- Bruce Momjian | 830 Blythe Avenue maillist@candle.pha.pa.us | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (610) 353-9879(w) + Christ can be your backup. | (610) 853-3000(h)
> Bruce Momjian wrote: > > > > Edmund, has this been fixed? > > > > > Hello, > > > > > > this problem appeared quite frequently in the last two years: > > > the libpq-function lo_export gives a segmentation fault. > > > > > > This happend with the current snapshot (I don't remember the > > > date, it was begin of June, filesize: 3980592) on Linux-2.0.34. > > > It worked with Postgresql-6.3.2. > > > > > > Edmund > > > Hi Bruce, > > it looks like the last time I tested lo_export it worked > just by chance. > > The bug seems to be in interfaces/libpq/fe-lobj.c line 424. > The two functions lo_import and lo_export are somehow > similar when exchanging the read/write for Unix file > and inv file. But whereas read() reads exactly BUFSIZ > bytes, lo_read() appends a '\0' after having read > BUFSIZ bytes. So line 424 should be: > > char buf[LO_BUFSIZE+1]; > > instead of: > > char buf[LO_BUFSIZE]; > > Could you please apply this bug-fix ? > Also the code example in the man page for > large-objects needs to be corrected. > > I can't do it by myself because I am on > vacation on a Greek island, and the only > message I'm seeing frequently is > 'modem hangup, no CARRIER' ... Extra null removed. -- Bruce Momjian | 830 Blythe Avenue maillist@candle.pha.pa.us | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (610) 353-9879(w) + Christ can be your backup. | (610) 853-3000(h)