Re: [PATCH v2] linux-user: Improve strace output of pread64() and pwrite64()

[Helge Deller <deller@gmx.de>]

On 1/30/23 10:26, Laurent Vivier wrote:
> Le 27/01/2023 à 21:58, Helge Deller a écrit :
>> Make the strace look nicer for those two syscalls.
>>
>> Signed-off-by: Helge Deller <deller@gmx.de>
>> ---
>> v2: Use regpairs_aligned() and target_offset64(), noticed by Laurent Vivier
>>
>> diff --git a/linux-user/strace.c b/linux-user/strace.c
>> index 82dc1a1e20..379536f5c9 100644
>> --- a/linux-user/strace.c
>> +++ b/linux-user/strace.c
>> @@ -3824,6 +3824,25 @@ print_rlimit64(abi_ulong rlim_addr, int last)
>>       }
>>   }
>>
>> +#if defined(TARGET_NR_pread64) || defined(TARGET_NR_pwrite64)
>> +static void
>> +print_preadwrite64(CPUArchState *cpu_env, const struct syscallname *name,
>> +           abi_long arg0, abi_long arg1, abi_long arg2,
>> +           abi_long arg3, abi_long arg4, abi_long arg5)
>> +{
>> +    if (regpairs_aligned(cpu_env, TARGET_NR_pread64)) {
>> +        arg3 = arg4;
>> +        arg4 = arg5;
>> +    }
>> +    print_syscall_prologue(name);
>> +    print_raw_param("%d", arg0, 0);
>> +    print_pointer(arg1, 0);
>> +    print_raw_param("%d", arg2, 0);
>> +    qemu_log("%lld", (long long)target_offset64(arg3, arg4));
>
> better to use:
>
> print_raw_param("%" PRIu64, target_offset64(arg3, arg4), 1);

I thought of that as well, but that won't work, as print_raw_param()
takes an "abi_long" value, which is just a 32-bit value on 32-bit targets.
See print_rlimit64(), it's used there with qemu_log() as well.

Helge