Re: [PATCH v2 6/6] linux-user: Add strace support for printing arguments of fallocate()

[Laurent Vivier <laurent@vivier.eu>]

Le 08/06/2020 à 18:43, Filip Bozuta a écrit :
> From: Filip Bozuta <Filip.Bozuta@syrmia.com>
> 
> This patch implements strace argument printing functionality for following syscall:
> 
>     *fallocate - manipulate file space
> 
>         int fallocate(int fd, int mode, off_t offset, off_t len)
>         man page: https://www.man7.org/linux/man-pages/man2/fallocate.2.html
> 
> Implementation notes:
> 
>     This syscall's second argument "mode" is composed of predefined values
>     which represent flags that determine the type of operation that is
>     to be performed on the file space. For that reason, a printing
>     function "print_fallocate" was stated in file "strace.list". This printing
>     function uses an already existing function "print_flags()" to print flags of
>     the "mode" argument. These flags are stated inside an array "falloc_flags"
>     that contains values of type "struct flags". These values are instantiated
>     using an existing macro "FLAG_GENERIC()". Most of these flags are defined
>     after kernel version 3.0 which is why they are enwrapped in an #ifdef
>     directive.
>     The syscall's third ant fourth argument are of type "off_t" which can
>     cause variations between 32/64-bit architectures. To handle this variation,
>     function "target_offset64()" was copied from file "strace.c" and used in
>     "print_fallocate" to print "off_t" arguments for 32-bit architectures.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/qemu.h      | 16 ++++++++++++++++
>  linux-user/strace.c    | 40 ++++++++++++++++++++++++++++++++++++++++
>  linux-user/strace.list |  2 +-
>  linux-user/syscall.c   | 16 ----------------
>  4 files changed, 57 insertions(+), 17 deletions(-)
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>