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From: Jakub Kicinski <jakub.kicinski@netronome.com>
To: Paul Chaignon <paul.chaignon@orange.com>
Cc: bpf@vger.kernel.org,
	Quentin Monnet <quentin.monnet@netronome.com>,
	paul.chaignon@gmail.com, netdev@vger.kernel.org,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>
Subject: Re: [PATCH bpf-next 2/3] bpftool: match programs by name
Date: Fri, 13 Dec 2019 09:56:59 -0800	[thread overview]
Message-ID: <20191213095659.2782ca57@cakuba.netronome.com> (raw)
In-Reply-To: <20191213124038.GB6538@Omicron>

On Fri, 13 Dec 2019 13:40:38 +0100, Paul Chaignon wrote:
> > > @@ -176,7 +177,20 @@ prog_parse_fds(int *argc, char ***argv, int *fds)
> > >  		}
> > >  		NEXT_ARGP();
> > >  
> > > -		return prog_fd_by_tag(tag, fds);
> > > +		return prog_fd_by_nametag(tag, fds, true);
> > > +	} else if (is_prefix(**argv, "name")) {
> > > +		char *name;
> > > +
> > > +		NEXT_ARGP();
> > > +
> > > +		name = **argv;
> > > +		if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {  
> > 
> > Is this needed? strncmp will simply never match, is it preferred to
> > hard error?  
> 
> I tried to follow the fail-early pattern of lookups by tag above.  

Right although tag does a scanf and if we didn't scan all letters 
we'd use uninit memory.

> I do like that there's a different error message for a longer than
> expected name.  Since libbpf silently truncates names, typing a
> longer name is not uncommon.

Ugh, I didn't realize libbpf truncates names. Okay, let's keep the
error for now so we can switch to truncation if users complain.

  reply	other threads:[~2019-12-13 20:40 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-10 16:05 [PATCH bpf-next 0/3] bpftool: match programs and maps by names Paul Chaignon
2019-12-10 16:06 ` [PATCH bpf-next 1/3] bpftool: match several programs with same tag Paul Chaignon
2019-12-10 17:29   ` Quentin Monnet
2019-12-13 18:10     ` Paul Chaignon
2019-12-10 20:36   ` Jakub Kicinski
2019-12-13 12:39     ` Paul Chaignon
2019-12-10 16:06 ` [PATCH bpf-next 2/3] bpftool: match programs by name Paul Chaignon
2019-12-10 17:29   ` Quentin Monnet
2019-12-10 21:04   ` Jakub Kicinski
2019-12-13 12:40     ` Paul Chaignon
2019-12-13 17:56       ` Jakub Kicinski [this message]
2019-12-10 16:06 ` [PATCH bpf-next 3/3] bpftool: match maps " Paul Chaignon
2019-12-10 17:29   ` Quentin Monnet

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