Hi,
I have managed to do few things. @Jim and @Mathew inputs were helpful. Thanks
So i have
[root@vcssx247-ldm7 ~]#dtrace -lvn fbt:my_mod:msg_recv1:entry
ID PROVIDER MODULE FUNCTION NAME
7090 fbt mymod msg_recv1 entry
Probe Description Attributes
Identifier Names: Private
Data Semantics: Private
Dependency Class: Unknown
Argument Attributes
Identifier Names: Private
Data Semantics: Private
Dependency Class: ISA
Argument Types
args[0]: mblk_t *
args[1]: uint_t
args[2]: uchar_t *
args[3]: ulong_t
And my probe then becomes:
dtrace -n 'msg_recv1:entry { printf("msg_recv1: %x, %x\n",
*(uchar_t*)args[0]->b_rptr, *((uchar_t*)args[0]->b_rptr + 1)); }'
Now, the args[0]->b_rptr points to my custom structure pkt_hdr_t { }.
Is is possible to typecast this args[0]->b_rptr to struct pkt_hdr_t *
in the dtrace script for better readable access of the private
structure variables instead of using offsets to b_rptr:
Something like this:
struct pkt_hdr_t* ppkt = (struct pkt_hdr_t*)args[0]->b_rptr;
Then printf("%d\n", ppkt->member1);
Regards
On Wed, Sep 20, 2017 at 12:13 AM, jim mauro <[email protected]> wrote:
> It's been a while (2+ years), but...
>
> The fbt provider makes function args available at entry probes via
> args[0] ... args[n]. This are typed.
>
> So you should be able to dereference structure members of sk_buff
> doing 'args[0]->structure_member', etc, when fbt:mymod:msg_recv:entry
> fires....
>
> args[1] will be the link value
> args[2] will be the src pointer.
>
> (jeez...I hope I'm remember this correctly. There was a book....).
>
> Thanks
> Jim
>
>
> On Tue, Sep 19, 2017 at 6:00 AM, Nayan Gadre <[email protected]> wrote:
>>
>> Hi,
>>
>> I am new to solaris dtrace debugging tool, but I have prior experience
>> with Linux SystemTap.
>>
>> I need to debug my Solaris kernel module particularly extract the data
>> in a structure passed by reference to my kernel function.
>>
>> msg_recv(struct sk_buff *skbp, uint_t link, uchar_t* src)
>> {
>> pkt_hdr_t *pkt;
>> pkt = (pkt_hdr_t *)skbp->data;
>> port = pkt->port;
>> }
>>
>> I have written a systemtap script in linux to access the argument and
>> extract data.
>>
>> How can I do this using DTRACE for solaris modules.
>>
>> I tried looking into the system and trying few commands, but thats all
>> i know about dtrace:
>>
>> [root@vcssx247-ldm7 ~]#dtrace -l | grep msg_recv
>> 7090 fbt mymod msg_recv1 entry
>> 7091 fbt mymod msg_recv1 return
>> 7548 fbt mymod msg_recv entry
>> 7549 fbt mymod msg_recv return
>>
>> Any pointers to correct, to the point documentation would be appreciated.
>>
>> Thanks
>> Nayan
>>
>
>
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