[CRIU] [PATCH] kdat: Don't open /run/criu.kdat if doesn't exists

[Dmitry Safonov]

2018-07-01 19:13 GMT+01:00 Radostin Stoyanov <rstoyanov1 at gmail.com>:
> When CRIU is called for a first time and the /run/criu.kdat file does
> not exists, the following warning is shown:
>         Warn  (criu/kerndat.c:847): Can't load /run/criu.kdat
>
> This patch is replacing this warning with a more appropriate debug message.
>         File /run/criu.kdat does not exist
>
> Signed-off-by: Radostin Stoyanov <rstoyanov1 at gmail.com>
> ---
>  criu/kerndat.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/criu/kerndat.c b/criu/kerndat.c
> index 9b93487c..57a97886 100644
> --- a/criu/kerndat.c
> +++ b/criu/kerndat.c
> @@ -842,6 +842,11 @@ static int kerndat_try_load_cache(void)
>  {
>         int fd, ret;
>
> +       if(access(KERNDAT_CACHE_FILE, F_OK) == -1) {
> +               pr_debug("File %s does not exist\n", KERNDAT_CACHE_FILE);
> +               return 1;
> +       }
> +
>         fd = open(KERNDAT_CACHE_FILE, O_RDONLY);
>         if (fd < 0) {
>                 pr_warn("Can't load %s\n", KERNDAT_CACHE_FILE);

I don't quite mind, but why do you need access() syscall?
Will checking (ENOENT == fd) work here?

It's not critical, but it's another syscall we'll be doing each time criu
is launched, so maybe makes sense not adding more calls there,
until necessary?

Thanks,
             Dmitry