dtrace discuss - Apr 2009 - Best way to deal with casting of undefined kernel structures

I''m trying to probe the ssfcp_transport function, to dig out the 
following...

   9481 fcp_transport(opaque_t port_handle, fc_packet_t *fpkt, int 
internal)
...
   9554         } else {
   9555             struct fcp_pkt *cmd;
   9556             struct fcp_port *pptr;
   9557
*   9558             cmd = (struct fcp_pkt *)fpkt->pkt_ulp_private;*
   9559             cmd->cmd_state = FCP_PKT_IDLE;
*   9560             pptr = ADDR2FCP(&cmd->cmd_pkt->pkt_address); *

fbt::ssfcp_transport:entry
{
  this->pkt=(fc_packet_t *)arg1;
  this->frame=(fc_frame_hdr_t )this->pkt->pkt_cmd_fhdr;

*  this->cmd=(fcp_pkt *)this->pkt->pkg_cmd_fhdr;*
  this->port=(fcp_port 
*)this->cmd->cmd_pkt->pkt_address->a_hba_tran->tran_hba_private;
}

# ./fcp.d
dtrace: failed to compile script ./fcp.d: line 55: syntax error near
")"

This suggests that dtrace doesn''t know what fcp_pkt type is.  I
followed
this up with...

BEGIN
{
  printf("%d %d",sizeof(fcp_pkt),offsetof(fcp_pkt,cmd_pkt));
}

...and confirmed that dtrace doesn''t have fcp_pkt or fcp_port defined
as
types.  I''ve tried including all of the "*.h" files...

#include <sys/mutex.h>
#include "/var/tmp/fc_types.h"
#include "/var/tmp/fc_appif.h"
#include "/var/tmp/fcpvar.h"

...but then get this error...

dtrace: failed to compile script ./fcp.d: "/var/tmp/fcpvar.h", line
343:
incomplete struct/union/enum struct modlinkage: port_fp_modlinkage

Is there a better way to do this?

Jim









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On Tue, Apr 28, 2009 at 02:28:45PM -0500, Jim Nissen
wrote:
> I''m trying to probe the ssfcp_transport function, to dig out the 
> following...
>
>   9555             struct fcp_pkt *cmd;
>
> *  this->cmd=(fcp_pkt *)this->pkt->pkg_cmd_fhdr;*
>
> # ./fcp.d
> dtrace: failed to compile script ./fcp.d: line 55: syntax error near
")"
>
> This suggests that dtrace doesn''t know what fcp_pkt type is.  I
followed
> this up with...
I think you want to do ''(struct fcp_pkt *)'' rather than
''(fcp_pkt *)'' just
as you would in C.

Adam

-- 
Adam Leventhal, Fishworks                     http://blogs.sun.com/ahl

Adam,
Thanks for responding.  I forgot to mention that I went the (struct...) 
route, to begin with.  I recreated that script w/meat of...

fbt::ssfcp_transport:entry
{
  this->pkt=(fc_packet_t *)arg1;
  this->frame=(fc_frame_hdr_t )this->pkt->pkt_cmd_fhdr;

  this->cmd=(struct fcp_pkt *)this->pkt->pkt_ulp_private;
*  this->scsipkt=(struct scsi_pkt *)this->cmd->cmd_pkt;    *
  this->scsiaddr=(struct scsi_address) this->scsipkt.pkt_address;
  this->hbatran=(struct scsi_hba_tran *)this->scsiaddr->a_hba_tran;
  this->port=(struct fcp_port *) this->hbatran->tran_hba_private;
/*  All the above is long for this...
  this->port=(struct fcp_port 
*)this->cmd->cmd_pkt->pkt_address->a_hba_tran->tran_hba_private;
*/
}

# ./fcp.d
dtrace: failed to compile script ./fcp.d: line 56: operator -> cannot be 
applied to a forward declaration: no struct fcp_pkt definition is available.

This is without the #includes.  fcp_pkt is defined as a structure in 
fcpvar.h  However, when I start the process of #includes ...

#include <sys/mutex.h>
#include <sys/modctl.h>
#include <sys/dditypes.h>
#include <sys/ddidmareq.h>
#include "/var/tmp/fc_types.h"
#include "/var/tmp/fc_appif.h"
#include "/var/tmp/fcpvar.h"

... I still end up getting ...

# ./fcp.d   
dtrace: failed to compile script ./fcp.d: "/var/tmp/fcpvar.h", line
350:
syntax error near "ddi_device_acc_attr_t"

The only definition of ddi_device_acc_attr_t, in fcpvar.h, is here...

struct fcp_port {
...
        ddi_dma_attr_t          port_data_dma_attr;
        ddi_dma_attr_t          port_cmd_dma_attr;
        ddi_dma_attr_t          port_resp_dma_attr;
*        ddi_device_acc_attr_t   port_dma_acc_attr;*
        /*
         * Field containing the hba_tran structure registered with SCSA.
         */
        struct scsi_hba_tran    *port_tran;
...
}

So, again, I''m left with what the best way to handle this.

Any clues?  I''m trying to get this script working for a case I am 
working on.

Thanks,
Jim


Adam Leventhal wrote:
> On Tue, Apr 28, 2009 at 02:28:45PM -0500, Jim Nissen wrote:
>   
>> I''m trying to probe the ssfcp_transport function, to dig out
the
>> following...
>>
>>   9555             struct fcp_pkt *cmd;
>>
>> *  this->cmd=(fcp_pkt *)this->pkt->pkg_cmd_fhdr;*
>>
>> # ./fcp.d
>> dtrace: failed to compile script ./fcp.d: line 55: syntax error near
")"
>>
>> This suggests that dtrace doesn''t know what fcp_pkt type is. 
I followed
>> this up with...
>>     
>
> I think you want to do ''(struct fcp_pkt *)'' rather than
''(fcp_pkt *)'' just
> as you would in C.
>
> Adam
>
>   
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On Wed, Apr 29, 2009 at 10:29:41AM -0500, Jim Nissen
wrote:
> Adam,
> Thanks for responding.  I forgot to mention that I went the (struct...) 
> route, to begin with.  I recreated that script w/meat of...
> 
> fbt::ssfcp_transport:entry
> {
>  this->pkt=(fc_packet_t *)arg1;
>  this->frame=(fc_frame_hdr_t )this->pkt->pkt_cmd_fhdr;
> 
>  this->cmd=(struct fcp_pkt *)this->pkt->pkt_ulp_private;
> *  this->scsipkt=(struct scsi_pkt *)this->cmd->cmd_pkt;    *
>  this->scsiaddr=(struct scsi_address) this->scsipkt.pkt_address;
>  this->hbatran=(struct scsi_hba_tran *)this->scsiaddr->a_hba_tran;
>  this->port=(struct fcp_port *) this->hbatran->tran_hba_private;
> /*  All the above is long for this...
>  this->port=(struct fcp_port 
>
*)this->cmd->cmd_pkt->pkt_address->a_hba_tran->tran_hba_private;
> */
> }
> 
> # ./fcp.d
> dtrace: failed to compile script ./fcp.d: line 56: operator -> cannot be
> applied to a forward declaration: no struct fcp_pkt definition is
available.
Try "struct fcp`fcp_pkt".  I assume the fcp module is loaded?

Cheers,
- jonathan

Jonathan Adams wrote:
> On Wed, Apr 29, 2009 at 10:29:41AM -0500, Jim Nissen wrote:
>   
>> Adam,
>> Thanks for responding.  I forgot to mention that I went the (struct...)
>> route, to begin with.  I recreated that script w/meat of...
>>
>> fbt::ssfcp_transport:entry
>> {
>>  this->pkt=(fc_packet_t *)arg1;
>>  this->frame=(fc_frame_hdr_t )this->pkt->pkt_cmd_fhdr;
>>
>>  this->cmd=(struct fcp_pkt *)this->pkt->pkt_ulp_private;
>> *  this->scsipkt=(struct scsi_pkt *)this->cmd->cmd_pkt;    *
>>  this->scsiaddr=(struct scsi_address) this->scsipkt.pkt_address;
>>  this->hbatran=(struct scsi_hba_tran
*)this->scsiaddr->a_hba_tran;
>>  this->port=(struct fcp_port *)
this->hbatran->tran_hba_private;
>> /*  All the above is long for this...
>>  this->port=(struct fcp_port 
>>
*)this->cmd->cmd_pkt->pkt_address->a_hba_tran->tran_hba_private;
>> */
>> }
>>
>> # ./fcp.d
>> dtrace: failed to compile script ./fcp.d: line 56: operator ->
cannot be
>> applied to a forward declaration: no struct fcp_pkt definition is
available.
>>     
>
> Try "struct fcp`fcp_pkt".  I assume the fcp module is loaded?
>   
Yes, fcp is loaded...

# modinfo | grep fcp
 35  133e4e0   3300   -   1  fcpci (FCode pci bus functions 1.9)
116 7bb26000  19350 294   1  fcp (SunFC FCP v20090122-1.132)

With fcp`fcp_pkt, I get the same error...

# ./fcp.d
dtrace: failed to compile script ./fcp.d: line 59: operator -> cannot be 
applied to a forward declaration: no struct fcp`fcp_pkt definition is 
available

Any other ideas?

Jim
> Cheers,
> - jonathan
>
>   
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