[plug] python head+wall issue

[Cameron Patrick]

On Mon, Dec 29, 2003 at 07:53:40PM +0800, Craig Ringer wrote:

| I've been trying to figure out why I can't truncate a file in Python. 
| I'm sure it's obvious, but if someone could supply the appropriate 
| clue-bat that'd be handy.

It looks to me like a screwy glibc/kernel problem with ftruncate64.  Out
of curiosity, are you running Linux 2.6?  I am.  Also, which
distribution and glibc version do you have?  (Debian sid, glibc
2.3.2.ds1-10 in my case.)  I've been meaning to switch back to 2.4 (due
to annoyance with 2.6) so I might reboot soon and see if that affects
anything.

I can confirm your problem, both in Python and with C:

$ cat foo.c
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

int main()
{
        int fd = open("bar", O_RDWR);
        if (fd < 0) perror("open");
        if (ftruncate64(fd, 0) < 0) perror("ftruncate64");
        if (ftruncate(fd, 0) < 0) perror("ftruncate");
        if (close(fd) < 0) perror("close");
}
$ gcc foo.c -o foo
$ echo asdf > bar
$ ./foo
ftruncate64: File too large

The ftruncate following it works fine.  The results are the same when
testing just ftruncate64 or ftruncate on their own.

Cameron.