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

[David Gibson <david@gibson.dropbear.id.au>]

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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().

>  	pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR);
>  	if (pcap_fd == -1) {
>  		perror("open");
> diff --git a/util.c b/util.c
> index 9cb705e..75aee81 100644
> --- a/util.c
> +++ b/util.c
> @@ -419,7 +419,11 @@ int pidfile_open(const char *path)
>  	if (!*path)
>  		return -1;
>  
> +	/* 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
> +	 */
>  	if ((fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC,
> +			     /* NOLINTNEXTLINE(android-cloexec-open) */
>  			     S_IRUSR | S_IWUSR)) < 0) {
>  		perror("PID file open");
>  		exit(EXIT_FAILURE);

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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