[PATCH 2/2] printrusage: Correctly print the long types from the rusage struct

[Alistair Francis]

On Wed, Mar 4, 2020 at 6:04 PM Dmitry V. Levin <ldv at altlinux.org> wrote:
>
> On Wed, Mar 04, 2020 at 05:30:34PM -0800, Alistair Francis wrote:
> > The kernel's rusage struct uses the kernel's __kernel_old_timeval which
> > means that even for 32-bit archs with 64-bit time_t (like RV32) the time
> > values are 32-bit.
> >
> > There are two possible options here:
> >  1. Use the glibc getrusage() function. Which takes a struct rusage with
> >     a 64-bit time_t but does a syscall with a 32-bit time_t and handles
> >     the conversion internally.
> >  2. Specify our own rusage struct that uses a long for the time.
> >
> > This patch fixes the failure useing option 2 above as we then get to
> > call the raw syscall.
> >
> > Signed-off-by: Alistair Francis <alistair.francis at wdc.com>
> > ---
> >  print_timeval.c   | 16 ++++++++++++++++
> >  printrusage.c     |  4 ++--
> >  tests/getrusage.c | 28 ++++++++++++++++++++++++++--
> >  3 files changed, 44 insertions(+), 4 deletions(-)
> >
> > diff --git a/print_timeval.c b/print_timeval.c
> > index ff87b27b..36bc843e 100644
> > --- a/print_timeval.c
> > +++ b/print_timeval.c
> > @@ -11,6 +11,10 @@
> >  #include DEF_MPERS_TYPE(timeval_t)
> >
> >  typedef struct timeval timeval_t;
> > +typedef struct old_timeval_t {
> > +     long tv_sec;
> > +     long tv_usec;
> > +} old_timeval_t;
>
> Sorry but this definition doesn't match the definition of struct
> __kernel_old_timeval in include/uapi/linux/time_types.h and
> arch/sparc/include/uapi/asm/posix_types.h files.

Do you mean it should be __kernel_long_t [1]? I can change it to
__kernel_long_t .

I'm not sure what to do to handle the space difference [2] though. I
think it ends up being long but I don't see a nice way to handle it.

Would you prefer the fist option mentioned in my commit message of
just using the glibc call?

1: https://github.com/torvalds/linux/blob/master/include/uapi/linux/time_types.h#L25
2: https://github.com/torvalds/linux/blob/master/arch/sparc/include/uapi/asm/posix_types.h#L26

Alistair

>
>
> --
> ldv