Re: stat64 on mips

[Justin Cormack <justin@specialbusservice.com>]

On Mon, Dec 30, 2013 at 9:29 PM, Rich Felker <dalias@aerifal.cx> wrote:
> On Mon, Dec 30, 2013 at 06:20:46PM +0000, Justin Cormack wrote:
>> MIPS is the most confusing architecture, but as far as I can make out,
>> the definition of struct stat64 that Musl has is probably the right
>> one for mips n32 but wrong for mips o32 which should be
>>
>> struct stat {
>>   unsigned long   st_dev;
>>   unsigned long   __st_pad0[3];
>>   unsigned long long      st_ino;
>>   mode_t          st_mode;
>>   nlink_t         st_nlink;
>>   uid_t           st_uid;
>>   gid_t           st_gid;
>>   unsigned long   st_rdev;
>>   unsigned long   __st_pad1[3];
>>   long long       st_size;
>>   time_t          st_atime;
>>   unsigned long   st_atime_nsec;
>>   time_t          st_mtime;
>>   unsigned long   st_mtime_nsec;
>>   time_t          st_ctime;
>>   unsigned long   st_ctime_nsec;
>>   unsigned long   st_blksize;
>>   unsigned long   __st_pad2;
>>   long long       st_blocks;
>> };
>>
>> It does appear that the syscalls for the two ABIs differ in this...
>
> This structure is identical to the one in musl except that it has
> 32-bit dev_t plus padding in place of 64-bit dev_t, and the musl
> version has reserved space at the end. Can you check whether the dev_t
> issue is actually a problem (it might be, based on endianness, and if
> so I think it would require ugly fixups in userspace)?

Ah no, my mistake, you are right, the padding seems correct and I was
getting confused as usual by dev_t. However the 64 bit dev_t is a
problem on bigendian mips.

(Whats the reason for Musl using 64 bit dev_t? glibc compatibility?)

justin