Re: [PATCH v2 5/8] treewide: Suppress clang-tidy warning if we already use O_CLOEXEC or if we can't

[Stefano Brivio <sbrivio@redhat.com>]

On Mon, 28 Oct 2024 12:00:53 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Fri, Oct 25, 2024 at 02:08:11PM +0200, Stefano Brivio wrote:
> > In pcap_init(), we open the packet capture file with O_CLOEXEC only
> > when possible.
> > 
> > In logfile_init() and pidfile_open(), the fact that we pass a third
> > 'mode' argument to open() seems to confuse the android-cloexec-open
> > checker in LLVM versions from 16 to 19 (at least).
> > 
> > The checker is suggesting to add O_CLOEXEC to 'mode', and not in
> > 'flags', where we already have it.
> > 
> > Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
> > ---
> >  log.c  | 4 ++++
> >  pcap.c | 1 +
> >  util.c | 4 ++++
> >  3 files changed, 9 insertions(+)
> > 
> > diff --git a/log.c b/log.c
> > index 6932885..154466f 100644
> > --- a/log.c
> > +++ b/log.c
> > @@ -416,7 +416,11 @@ void logfile_init(const char *name, const char *path, size_t size)
> >  	if (readlink("/proc/self/exe", exe, PATH_MAX - 1) < 0)
> >  		die_perror("Failed to read own /proc/self/exe link");
> >  
> > +	/* We use O_CLOEXEC here, but clang-tidy as of LLVM 16 to 19 looks for
> > +	 * it in the 'mode' argument if we have one, so...
> > +	 */
> >  	log_file = open(path, O_CREAT | O_TRUNC | O_APPEND | O_RDWR | O_CLOEXEC,
> > +			/* NOLINTNEXTLINE(android-cloexec-open) */
> >  			S_IRUSR | S_IWUSR);
> >  	if (log_file == -1)
> >  		die_perror("Couldn't open log file %s", path);
> > diff --git a/pcap.c b/pcap.c
> > index 6ee6cdf..6753cfb 100644
> > --- a/pcap.c
> > +++ b/pcap.c
> > @@ -167,6 +167,7 @@ void pcap_init(struct ctx *c)
> >  		return;
> >  
> >  	flags |= c->foreground ? O_CLOEXEC : 0;
> > +	/* NOLINTNEXTLINE(android-cloexec-open): ...only where possible */  
> 
> Hmm... why do we need the conditional on c->foreground?  It's
> close-on-exec(), not close-on-fork() or close-on-daemonize().

Oops, see also 20220823063151.854034-4-david@gibson.dropbear.id.au, I
never learn. Fixing.

-- 
Stefano