Re: [PATCH] elfclassify tool

[Mark Wielaard <mark@klomp.org>]

On Mon, Jul 29, 2019 at 11:16:31AM +0200, Florian Weimer wrote:
> * Mark Wielaard:
> 
> > +/* Called to process standard input if flag_stdin is not no_stdin.  */
> > +static void
> > +process_stdin (int *status)
> > +{
> > +  char delim;
> > +  if (flag_stdin == do_stdin0)
> > +    delim = '\0';
> > +  else
> > +    delim = '\n';
> > +
> > +  char *buffer = NULL;
> > +  size_t buffer_size = 0;
> > +  while (true)
> > +    {
> > +      ssize_t ret = getdelim (&buffer, &buffer_size, delim, stdin);
> > +      if (ferror (stdin))
> > +	{
> > +	  current_path = NULL;
> > +	  issue (errno, N_("reading from standard input"));
> > +	  break;
> > +	}
> > +      if (feof (stdin))
> > +        break;
> > +      if (ret < 0)
> > +        abort ();           /* Cannot happen due to error checks above.  */
> > +      if (delim != '\0' && ret > 0)
> > +        buffer[ret - 1] = '\0';
> 
> I think this can overwrite the last character of the last line if the
> file does not end with '\n'.

I see.  "The buffer is null-terminated and includes the newline
character, if one was found."

So the test should be:

diff --git a/src/elfclassify.c b/src/elfclassify.c
index ebd42c1d5..b17d14d45 100644
--- a/src/elfclassify.c
+++ b/src/elfclassify.c
@@ -862,7 +862,7 @@ process_stdin (int *status)
         break;
       if (ret < 0)
         abort ();           /* Cannot happen due to error checks above.  */
-      if (delim != '\0' && ret > 0)
+      if (delim != '\0' && ret > 0 && buffer[ret - 1] == '\n')
         buffer[ret - 1] = '\0';
       current_path = buffer;
       process_current_path (status);

Thanks,

Mark