On 11-10-16 03:21 PM, Jan Kratochvil wrote:
> On Fri, 30 Sep 2011 21:31:33 +0200, Aleksandar Ristovski wrote:
>>      * solib-svr4.c (read_program_header): If PT_PHDR is present, use it
>>      to calculate correct address in case of PIE.
>
> FSF ChangeLog should describe the changes, not their reason.  Therefore:
> 	* solib-svr4.c (read_program_header): New variable pt_phdr, initialize
> 	it from target PT_PHDR p_vaddr, relocate sect_addr by it.


Change log changed (see below).


>>
>> +  pt_phdr = (CORE_ADDR)-1; /* Address of the first entry. If not PIE,
>> +			      this will be zero.
>> +			      For PIE, it will be unrelocated at_phdr. */
>
> There is CORE_ADDR_MAX.  But I would prefer new `int pt_phdr_p' as "predicate"
> boolean flag for valid pt_phdr value, these special values are fragile and one
> has to think whether they can happen.


pt_phdr_p introduced. Also, pt_phdr initialized to 0 even though not 
strictly necessary, but gcc complained about possible uninitialized use.


>
>
>> +
>>     /* Find the requested segment.  */
>>     if (type == -1)
>>       {
>> @@ -427,6 +431,11 @@ read_program_header (int type, int *p_se
>>   	    return 0;
>>
>>   	  if (extract_unsigned_integer ((gdb_byte *)phdr.p_type,
>> +					4, byte_order) == PT_PHDR)
>> +	    pt_phdr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
>> +						4, byte_order);
>> +
>> +	  if (extract_unsigned_integer ((gdb_byte *)phdr.p_type,
>>   					4, byte_order) == type)
>
> That p_type could be decoded only once.  Also any casta are `(type) val' with
> a space accoridng to GCS (GNU Coding Standards).

Cast fixed, p_type decoded only once.

>>     if (target_read_memory (sect_addr, buf, sect_size))
>
>
> Just about the style, I do not see any problems of the patch, thanks.
>
> Wrote the testcase, it is probably GNU/Linux-specific.

I was contemplating a testcase but I couldn't think of a trick to "make" 
gdb not find the executable... Thanks for the test.


>
> I would like to review yet the changes.

Revised patch attached.



Thanks,

Aleksandar


New change log:

<date>  Aleksandar Ristovski  <aristovski@qnx.com>

         * solib-svr4.c (read_program_header): New variable pt_phdr, 
initialize
         it from target PT_PHDR p_vaddr, relocate sect_addr by it.