Re: segfault in stat

[Andries . Brouwer]

On Fri, Sep 29, 2000 at 04:45:56PM -0500, Nathan Straz wrote:
> On Fri, Sep 29, 2000 at 11:07:23PM +0200, address@hidden wrote:
> >     >>>>> Nathan Straz writes:
> > 
> >      > I was doing some negative testing of stat(2) on Linux with glibc 
> > 2.1.3
> >      > and I was able to provoke a segfault.  Here is the code:
> 
> Okay, it seems that everyone seemed to miss the point that is was doing
> "negative testing."  That means I MEANT to send a bad pointer to see
> that the results are correct.  

You evoke undefined behaviour.
So *any* result you find would be correct, including reformatting your disk 
drive.

Prescribed error returns:
---------------------------------------------------------------------------
The stat( ) function shall fail if:
[EACCES]        Search permission is denied for a component of the path prefix.
[EIO]           An error occurred while reading from the file system.
[ELOOP]         A loop exists in symbolic links encountered during resolution
                of the path argument.
[ENAMETOOLONG]  The length of the path argument exceeds PATH_MAX or a path name
                component is longer than NAME_MAX.
[ENOENT]        A component of path does not name an existing file or path is
                an empty string.
[ENOTDIR]       A component of the path prefix is not a directory.
[EOVERFLOW]     The file size in bytes or the number of blocks allocated to
                the file or the file serial number cannot be represented
                correctly in the structure pointed to by buf.
---------------------------------------------------------------------------

Allowed error returns:
---------------------------------------------------------------------------
The stat( ) function may fail if:
[ELOOP]         More than SYMLOOP_MAX symbolic links were encountered during
                resolution of the path argument.
[ENAMETOOLONG]  As a result of encountering a symbolic link in resolution
                of the path argument, the length of the substituted path name
                string exceeded PATH_MAX.
[EOVERFLOW]     A value to be stored would overflow one of the members
                of the stat structure.
---------------------------------------------------------------------------

General errors include:

[EFAULT]        Bad address. The system detected an invalid address
                in attempting to use an argument of a call. The reliable
                detection of this error cannot be guaranteed, and when not
                detected may result in the generation of a signal, indicating
                an address violation, which is sent to the process.

Andries