Sender: rich AT phekda DOT freeserve DOT co DOT uk
Message-ID: <3E02432B.EF550904@phekda.freeserve.co.uk>
Date: Thu, 19 Dec 2002 22:07:39 +0000
From: Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
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To: djgpp-workers AT delorie DOT com
Subject: Re: Bugs in __solve_symlinks
References: <200212192013 DOT gBJKDm125557 AT brother DOT ludd DOT luth DOT se>
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Reply-To: djgpp-workers AT delorie DOT com

Hello.

Martin Str|mberg wrote:
> 
> According to Richard Dawe:
> > * It doesn't cope with symlinks that point to themselves. For instance:
> >
> >     ln -s a a
> >
> > Try to stat the file 'a'. It fails with ELOOP, but it should return
> > information about the file 'a'.
> 
> Are you sure?

From the description of stat in draft D7 of the new POSIX standard by the
Austin Group:

"If the named file is a symbolic link, the stat( ) function shall continue
pathname resolution using the contents of the symbolic link, and shall return
information pertaining to the resulting file if the file exists."

So if I stat 'a' above, I would expect it to resolve the symlink to 'a' and
then return information about the symlink 'a', e.g.: the st_mode field would
have the S_IFLNK bit set.

Hmmm, it doesn't work that on Linux. Test program:

---Start teststat.c---
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>

int
main (int argc, char *argv[])
{
  struct stat sbuf;
  int ret, i;

  for (i = 1; i < argc; i++) {
    ret = stat(argv[i], &sbuf);
    if (ret < 0)
      perror(argv[0]);
  }

  return(EXIT_SUCCESS);
}
---End teststat.c---

iolanthe:~ =] ln -nsf a a
iolanthe:~ =] ls -l a 
lrwxrwxrwx    1 rich     rich            1 Dec 19 22:05 a -> a
iolanthe:~ =] ./src/tmp/teststat a
./src/tmp/teststat: Too many levels of symbolic links

I guess I read the standard wrong. Sorry.

The left 'a' in 'a -> a' above is bright blue, to indicate that the link is
satisfied. An equivalent test with DJGPP shows the left 'a' in black on a red
background, indicating that the link is broken. I wonder why that is.

Bye, Rich =]

-- 
Richard Dawe [ http://www.phekda.freeserve.co.uk/richdawe/ ]