[DTrace-devel] [PATCH 07/22] Supply a default probe_info()

[Kris Van Hees]

Is this still needed after the fix we put in for dealing with argc == -1, i.e.
commit 0e3231a268 "ident: fix unsigned vs signed comparison" ?

On Thu, Aug 29, 2024 at 01:22:04AM -0400, eugene.loh at oracle.com wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
> ---
>  libdtrace/dt_probe.c        |  4 +++-
>  libdtrace/dt_prov_cpc.c     | 11 -----------
>  libdtrace/dt_prov_dtrace.c  | 10 ----------
>  libdtrace/dt_prov_fbt.c     | 10 ----------
>  libdtrace/dt_prov_profile.c | 11 -----------
>  5 files changed, 3 insertions(+), 43 deletions(-)
> 
> diff --git a/libdtrace/dt_probe.c b/libdtrace/dt_probe.c
> index 0b53121a..ab90d2ed 100644
> --- a/libdtrace/dt_probe.c
> +++ b/libdtrace/dt_probe.c
> @@ -892,8 +892,10 @@ dt_probe_args_info(dtrace_hdl_t *dtp, dt_probe_t *prp)
>  	/* Only retrieve probe argument information once per probe. */
>  	if (prp->argc != -1)
>  		return 0;
> -	if (!prp->prov->impl->probe_info)
> +	if (!prp->prov->impl->probe_info) {
> +		prp->argc = 0;
>  		return 0;
> +	}
>  	rc = prp->prov->impl->probe_info(dtp, prp, &argc, &argv);
>  	if (rc == -1)
>  		return rc;
> diff --git a/libdtrace/dt_prov_cpc.c b/libdtrace/dt_prov_cpc.c
> index 08689b35..8f33cf58 100644
> --- a/libdtrace/dt_prov_cpc.c
> +++ b/libdtrace/dt_prov_cpc.c
> @@ -451,16 +451,6 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  	return nattach > 0 ? 0 : -1;
>  }
>  
> -static int probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
> -		      int *argcp, dt_argdesc_t **argvp)
> -{
> -	/* cpc-provider probe arguments are not typed */
> -	*argcp = 0;
> -	*argvp = NULL;
> -
> -	return 0;
> -}
> -
>  static void detach(dtrace_hdl_t *dtp, const dt_probe_t *prp)
>  {
>  	cpc_probe_t	*datap = prp->prv_data;
> @@ -504,7 +494,6 @@ dt_provimpl_t	dt_cpc = {
>  	.load_prog	= &dt_bpf_prog_load,
>  	.trampoline	= &trampoline,
>  	.attach		= &attach,
> -	.probe_info	= &probe_info,
>  	.detach		= &detach,
>  	.probe_destroy	= &probe_destroy,
>  	.destroy	= &destroy,
> diff --git a/libdtrace/dt_prov_dtrace.c b/libdtrace/dt_prov_dtrace.c
> index bf87cb05..a9deccee 100644
> --- a/libdtrace/dt_prov_dtrace.c
> +++ b/libdtrace/dt_prov_dtrace.c
> @@ -273,15 +273,6 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  	return dt_tp_probe_attach(dtp, prp, bpf_fd);
>  }
>  
> -static int probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
> -		      int *argcp, dt_argdesc_t **argvp)
> -{
> -	*argcp = 0;			/* no arguments */
> -	*argvp = NULL;
> -
> -	return 0;
> -}
> -
>  /*
>   * Try to clean up system resources that may have been allocated for this
>   * probe.
> @@ -317,7 +308,6 @@ dt_provimpl_t	dt_dtrace = {
>  	.trampoline	= &trampoline,
>  	.load_prog	= &dt_bpf_prog_load,
>  	.attach		= &attach,
> -	.probe_info	= &probe_info,
>  	.detach		= &detach,
>  	.probe_destroy	= &dt_tp_probe_destroy,
>  };
> diff --git a/libdtrace/dt_prov_fbt.c b/libdtrace/dt_prov_fbt.c
> index 62c568ce..21f63ddf 100644
> --- a/libdtrace/dt_prov_fbt.c
> +++ b/libdtrace/dt_prov_fbt.c
> @@ -411,15 +411,6 @@ static int kprobe_attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  	return dt_tp_probe_attach(dtp, prp, bpf_fd);
>  }
>  
> -static int kprobe_probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
> -			     int *argcp, dt_argdesc_t **argvp)
> -{
> -	*argcp = 0;			/* no arguments by default */
> -	*argvp = NULL;
> -
> -	return 0;
> -}
> -
>  /*
>   * Try to clean up system resources that may have been allocated for this
>   * probe.
> @@ -469,7 +460,6 @@ dt_provimpl_t	dt_fbt_kprobe = {
>  	.load_prog	= &dt_bpf_prog_load,
>  	.trampoline	= &kprobe_trampoline,
>  	.attach		= &kprobe_attach,
> -	.probe_info	= &kprobe_probe_info,
>  	.detach		= &kprobe_detach,
>  	.probe_destroy	= &dt_tp_probe_destroy,
>  };
> diff --git a/libdtrace/dt_prov_profile.c b/libdtrace/dt_prov_profile.c
> index bc224348..e1369ca9 100644
> --- a/libdtrace/dt_prov_profile.c
> +++ b/libdtrace/dt_prov_profile.c
> @@ -299,16 +299,6 @@ static int attach(dtrace_hdl_t *dtp, const dt_probe_t *prp, int bpf_fd)
>  	return nattach > 0 ? 0 : -1;
>  }
>  
> -static int probe_info(dtrace_hdl_t *dtp, const dt_probe_t *prp,
> -		      int *argcp, dt_argdesc_t **argvp)
> -{
> -	/* profile-provider probe arguments are not typed */
> -	*argcp = 0;
> -	*argvp = NULL;
> -
> -	return 0;
> -}
> -
>  static void detach(dtrace_hdl_t *dtp, const dt_probe_t *prp)
>  {
>  	profile_probe_t	*pp = prp->prv_data;
> @@ -337,7 +327,6 @@ dt_provimpl_t	dt_profile = {
>  	.load_prog	= &dt_bpf_prog_load,
>  	.trampoline	= &trampoline,
>  	.attach		= &attach,
> -	.probe_info	= &probe_info,
>  	.detach		= &detach,
>  	.probe_destroy	= &probe_destroy,
>  };
> -- 
> 2.43.5
>