[lxc-devel] [PATCH 2/6] Delete string from array Add function to delete a string from a non-null terminated buffer

[Serge Hallyn]

Quoting Christian Brauner (christianvanbrauner at gmail.com):
> On Mon, Sep 07, 2015 at 05:03:37PM +0000, Serge Hallyn wrote:
> > Quoting Serge Hallyn (serge.hallyn at ubuntu.com):
> > > Quoting Christian Brauner (christianvanbrauner at gmail.com):
> > > 
> > > I'm probably wrong, but
> > > 
> > > 1. if the buffer is non-null-terminated, then can't the memmove of
> > > 	strlen(del) - needlelen + 1 end up in a segv?
> > > 2. the comment should probably mention newlines.  If needle doesn't
> > > 	include newline, and the string is a policy, we'll end up
> > > 	with extra newlines.  Which may not matter, unless we do
> > > 	thousands of operations on a container...
> > 
> > In fact, if it is not null-terminated, you can't do the strlen(del)
> > safely, can you?
> 
> Right, I would change
>         memmove(del, del + needlelen, strlen(del) - needlelen + 1);
> to
>         memmove(del, del + needlelen, strnlen(del, haystacklen) - needlelen);

Should probably be somethin glike

         memmove(del, del + needlelen, strnlen(del, haystacklen-del) - needlelen);
	 del[needlelen] = '\0';

I'm not convinced eventhat is right.  We may need to either always assume it is
null-terminated, or always track the current valid length of the string.  (and/or
keep extra state showing whether null-terminated or not)

> The Current master relies on the same idea in mod_rdep(), I'll send a patch for
> the current master in a few minutes, unless you're on it right now.

I'm not.  Thanks.