Re: [PATCH v2 0/2] Fix sockaddr handling in NFSD trace points

[Chuck Lever III <chuck.lever@oracle.com>]

> On Jan 10, 2022, at 6:31 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> On Mon, 10 Jan 2022 11:05:35 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
>>> I haven't quite been able to figure out how to handle the 
>>> TP_printk() part of this equation. `trace-cmd report` displays
>>> something like "addr=ARG TYPE NOT FIELD BUT 7". 
>>> 
>>> Thoughts or advice appreciated.  
>> 
>> I'll take a look into it.
> 
> If you add this to libtraceevent, it will work:

Thank you Steven! I will set up my current test system with
a locally-built trace-cmd and try this out. I can send a
proper patch that introduces the helper macros in my cover
letter's pseudo-code example today or tomorrow.


> diff --git a/src/event-parse.c b/src/event-parse.c
> index 9bd605d..033529c 100644
> --- a/src/event-parse.c
> +++ b/src/event-parse.c
> @@ -5127,6 +5127,8 @@ static int print_ipsa_arg(struct trace_seq *s, const char *ptr, char i,
> 	unsigned char *buf;
> 	struct sockaddr_storage *sa;
> 	bool reverse = false;
> +	unsigned int offset;
> +	unsigned int len;
> 	int rc = 0;
> 	int ret;
> 
> @@ -5152,27 +5154,42 @@ static int print_ipsa_arg(struct trace_seq *s, const char *ptr, char i,
> 		return rc;
> 	}
> 
> -	if (arg->type != TEP_PRINT_FIELD) {
> -		trace_seq_printf(s, "ARG TYPE NOT FIELD BUT %d", arg->type);
> -		return rc;
> -	}
> +	/* evaluate if the arg has a typecast */
> +	while (arg->type == TEP_PRINT_TYPE)
> +		arg = arg->typecast.item;
> +
> +	if (arg->type == TEP_PRINT_FIELD) {
> 
> -	if (!arg->field.field) {
> -		arg->field.field =
> -			tep_find_any_field(event, arg->field.name);
> 		if (!arg->field.field) {
> -			do_warning("%s: field %s not found",
> -				   __func__, arg->field.name);
> -			return rc;
> +			arg->field.field =
> +				tep_find_any_field(event, arg->field.name);
> +			if (!arg->field.field) {
> +				do_warning("%s: field %s not found",
> +					   __func__, arg->field.name);
> +				return rc;
> +			}
> 		}
> +
> +		offset = arg->field.field->offset;
> +		len = arg->field.field->size;
> +
> +	} else if (arg->type == TEP_PRINT_DYNAMIC_ARRAY) {
> +
> +		dynamic_offset_field(event->tep, arg->dynarray.field, data,
> +				     size, &offset, &len);
> +
> +	} else {
> +		trace_seq_printf(s, "ARG NOT FIELD NOR DYNAMIC ARRAY BUT TYPE %d",
> +				 arg->type);
> +		return rc;
> 	}
> 
> -	sa = (struct sockaddr_storage *) (data + arg->field.field->offset);
> +	sa = (struct sockaddr_storage *)(data + offset);
> 
> 	if (sa->ss_family == AF_INET) {
> 		struct sockaddr_in *sa4 = (struct sockaddr_in *) sa;
> 
> -		if (arg->field.field->size < sizeof(struct sockaddr_in)) {
> +		if (len < sizeof(struct sockaddr_in)) {
> 			trace_seq_printf(s, "INVALIDIPv4");
> 			return rc;
> 		}
> @@ -5185,7 +5202,7 @@ static int print_ipsa_arg(struct trace_seq *s, const char *ptr, char i,
> 	} else if (sa->ss_family == AF_INET6) {
> 		struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) sa;
> 
> -		if (arg->field.field->size < sizeof(struct sockaddr_in6)) {
> +		if (len < sizeof(struct sockaddr_in6)) {
> 			trace_seq_printf(s, "INVALIDIPv6");
> 			return rc;
> 		}

--
Chuck Lever