Re: [PATCH v4 05/15] xenctx: Add command line option -D (--decode-as-ascii)

[Don Slutz <dslutz@verizon.com>]

On 03/19/14 12:09, George Dunlap wrote:
> On 03/18/2014 10:15 PM, Don Slutz wrote:
>> If specified, output ascii version of stack also.
>>
>> Here is an example:
>>
>> Stack:
>>   ffffffff80048d19 0000000000200800 ffffffff803e7801 
>> 0000000000086800  .......... ......x>......h......
>>   0000000000000000 ffffffff80430720 ffffffff803e722f 
>> 80008e000010019c  ........ .C...../r>.............
>>   00000000ffffffff 0000000000000000 0000000000000000 
>> 0000000000200000  .......................... .....
>>   0000000000000000 0000000000000000 ................
>>
>> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
>> ---
>>   tools/xentrace/xenctx.c | 35 ++++++++++++++++++++++++++++++++++-
>>   1 file changed, 34 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
>> index 62a8519..850e091 100644
>> --- a/tools/xentrace/xenctx.c
>> +++ b/tools/xentrace/xenctx.c
>> @@ -38,6 +38,7 @@ static struct xenctx {
>>       int multiple_pages;
>>       int bytes_per_line;
>>       int lines;
>> +    int decode_as_ascii;
>>       int all_vcpus;
>>       int self_paused;
>>       xc_dominfo_t dominfo;
>> @@ -665,6 +666,7 @@ static int print_stack(vcpu_guest_context_any_t 
>> *ctx, int vcpu, int width)
>>       guest_word_t frame;
>>       guest_word_t word;
>>       guest_word_t *p;
>> +    guest_word_t ascii[MAX_BYTES_PER_LINE/4];
>>       int i;
>>         if ( width )
>> @@ -679,6 +681,9 @@ static int print_stack(vcpu_guest_context_any_t 
>> *ctx, int vcpu, int width)
>>           printf("Stack:\n");
>>           for (i = 1; i < xenctx.lines + 1 && stack < stack_limit; i++)
>>           {
>> +            int j = 0;
>> +            int k;
>> +
>>               while ( stack < stack_limit &&
>>                       stack < stack_pointer(ctx) + i * 
>> xenctx.bytes_per_line )
>>               {
>> @@ -686,10 +691,32 @@ static int print_stack(vcpu_guest_context_any_t 
>> *ctx, int vcpu, int width)
>>                   if ( !p )
>>                       return -1;
>>                   word = read_stack_word(p, width);
>> +                if ( xenctx.decode_as_ascii )
>> +                    ascii[j++] = word;
>>                   printf(" ");
>>                   print_stack_word(word, width);
>>                   stack += width;
>>               }
>> +            printf("  ");
>> +            if ( xenctx.decode_as_ascii )
>> +            {
>> +                for (k = j; k < xenctx.bytes_per_line / width; k++)
>> +                    printf(" %*s", width*2, "");
>
> It might be nice to have a comment here explaining what this is doing: 
> maybe, "Line up ascii output if less than bytes_per_line were printed."
>

Ok.

> Also, the printf("  ") line above should probably go under this for 
> loop.  It goes here logically, and it avoids printing trailing 
> whitespace if decode_as_ascii is false.
>

Will do.  Thanks,
     -Don Slutz

>  -George
>