[INPUT] Fix NUL skipping in preadbuffer

On Sun, Sep 25, 2005 at 07:50:54PM +0000, Gerrit Pape wrote:
> On Sat, Sep 03, 2005 at 02:56:00PM +0200, Martin Dickopp wrote:
> > When analysing the bug I came to the following conclusion: The loop
> > beginning at input.c:302 overwrites a single input line with itself,
> > skipping NUL characters. Therefore, after the loop the line buffer
> > has less characters than originally read if and only if the input line
> > contains NUL characters.
>
> yes.  Thanks a lot for the details and patch.
>
> > The pointer that is used to read from the buffer, 'parsenextc' (cf.
> > input.h:66), is also used as the beginning of the next line in
> > input.c:296. This fails if the buffer contains less characters
> > than originally read into it due to NUL characters.
> >
> > The proposed patch (attached) keeps track of the number of skipped
> > characters and advances 'parsenextc' accordingly before processing
> > the next input line.
>
> Hi Herbert, please see
>  http://bugs.debian.org/317516

Instead of moving the characters in the loop, we will do memmove every
time we see a NUL character.  This hurts if there are a lot of NUL
characters, but should be a win in normal situations.

1 files changed, 4 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index a01503a..e7253d1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2005-10-01  Herbert Xu <herbert@gondor.apana.org.au>
+
+	* Skip NUL characters properly in input.c
+
 2005-03-28  Herbert Xu <herbert@gondor.apana.org.au>
 
 	* Removed some unnecessary inclusions of input.h.