[PATCH 1/1] statfs64 should be weak-aliased to statfs on mips64/n64 as on X86-64

[Rongqing Li]

Could anyone give any comments about this fix?
Thanks

-Roy

On 08/20/2011 09:06 AM, Rongqing Li wrote:
> The below is analysis for this patch. All the test is done on mips64
>
> ==================================
> #This program works well
>
> main()
> {
> statfs("/tmp", sfbuf);
> }
> ==================================
> #This program does not work
>
> main()
> {
> statfs64("/tmp", sfbuf);
> }
> ==================================
> #This program does not work if we define _FILE_OFFSET_BITS=64
> #since statfs would be linked to statfs64 on this condition
>
> #define _FILE_OFFSET_BITS=64
> #include <*.h>
> main()
> {
> statfs("/tmp", sfbuf);
> }
> ==================================
> #The below is elf information
>
> -bash-3.2$ readelf -h ./mabi_64/libc.so
> ELF Header:
> Magic: 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00
> Class: ELF64
> Data: 2's complement, big endian
> OS/ABI: UNIX - System V
> ABI Version: 0
> Type: DYN (Shared object file)
> Machine: MIPS R3000
> Flags: 0x60000007, noreorder, pic, cpic, mips64
> ....
>
>
> -bash-3.2$ readelf -s ./mabi_64/libc.so |grep statfs
> 6746: 00000000000ee39c 28 FUNC GLOBAL DEFAULT 11 __statfs
> 6806: 00000000000ee400 8 FUNC WEAK DEFAULT 11 statfs64
> 6821: 00000000000ee39c 28 FUNC WEAK DEFAULT 11 statfs
>
>
> -bash-3.2$ objdump -dS ./mabi_64/libc.so
>
> 00000000000ee39c <__statfs>:
> ee39c: 2402140e li v0,5134
> ee3a0: 0000000c syscall
> ee3a4: 14e0fff6 bnez a3,ee380 <__fxstatat64+0xb0>
> ee3a8: 00000000 nop
> ee3ac: 03e00008 jr ra
> ee3b0: 00000000 nop
> ...
> ee3c0: 0380082d move at,gp
> ee3c4: 3c1c000a lui gp,0xa
> ee3c8: 279c6b14 addiu gp,gp,27412
> ee3cc: 0399e02d daddu gp,gp,t9
> ee3d0: df998588 ld t9,-31352(gp)
> ee3d4: 03200008 jr t9
> ee3d8: 0020e02d move gp,at
>
> 00000000000ee400 <statfs64>:
> ee400: 03e00008 jr ra
> ee404: 00000000 nop
> ...
>
> =========================================================
> The statfs64 in libc does not any work and is dummy function
> since the linux kernel does not implement the statfs64 syscall
> when define _MIPS_SIM_ABI64,
>
> the reason why statfs64 syscall is not implemented is that statfs
> has equal function to statfs64 on mips64, I think.
>
> =========================================================
>
> On x86-64, statfs64 in libc has its true implementation since
> the statfs64 syscall exists in kernel.
>
> But statfs64 is weak-aliased to statfs at last, not call the true
> statfs64 syscall on x86_64.
>
> The below information comes from common_pc_64.
>
> readelf -s libc-2.11.1.so |grep statfs
> 1241: 00000000000c2350 37 FUNC GLOBAL DEFAULT 11 __statfs@@GLIBC_2.2.5
> 1564: 00000000000c2350 37 FUNC WEAK DEFAULT 11 statfs@@GLIBC_2.2.5
> 1761: 00000000000c2350 37 FUNC WEAK DEFAULT 11 statfs64@@GLIBC_2.2.5
>
> ====================================================
> So I think the mips64 should have the same result.
>
> ====================================================
>
>
> On 08/19/2011 05:50 PM, rongqing.li@windriver.com wrote:
>> From: Roy.Li<rongqing.li@windriver.com>
>>
>> statfs64 is null function since __NR_statfs64 is not defined when gcc
>> uses _MIPS_SIM_ABI64.
>>
>> When macro _FILE_OFFSET_BITS=64, statfs function becomes statfs64,
>> the result is these two functions can not work.
>>
>> Signed-off-by: Roy.Li<rongqing.li@windriver.com>
>> ---
>> .../unix/sysv/linux/mips/mips64/n64/syscalls.list | 1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list
>> b/sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list
>> index 8d70e45..a93943d 100644
>> --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list
>> +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list
>> @@ -5,3 +5,4 @@ sync_file_range - sync_file_range Ci:iiii sync_file_range
>> prlimit EXTRA prlimit64 i:iipp prlimit prlimit64
>>
>> fanotify_mark EXTRA fanotify_mark i:iiiis fanotify_mark
>> +statfs - statfs i:sp __statfs statfs statfs64
>
>
>

-- 
Best Reagrds,
Roy | RongQing Li