On Fri, 21 Apr 2023 at 11:12, Xueming Feng <kuro@xxxxxxxx> wrote:
>
> When using `bpftool map dump` in plain format, it is usually
> more convenient to show the inner map id instead of raw value.
> Changing this behavior would help with quick debugging with
> `bpftool`, without disruption scripted behavior. Since user
s/disruption/disrupting/ ?
> could dump the inner map with id, but need to convert value.
>
> Signed-off-by: Xueming Feng <kuro@xxxxxxxx>
Thanks for this patch! It looks good, with some minor comments below.
> ---
> tools/bpf/bpftool/main.c | 16 ++++++++++++++++
> tools/bpf/bpftool/main.h | 1 +
> tools/bpf/bpftool/map.c | 9 +++++++--
> 3 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
> index 08d0ac543c67..d297200c91f7 100644
> --- a/tools/bpf/bpftool/main.c
> +++ b/tools/bpf/bpftool/main.c
> @@ -251,6 +251,22 @@ int detect_common_prefix(const char *arg, ...)
> return 0;
> }
>
> +void fprint_uint(FILE *f, void *arg, unsigned int n)
I suppose you based this function on fprint_hex(). But for your
function, let's remove the first argument? We always print to stdout.
We can always turn it to a "fprint" version again if we need to print
elsewhere in the future.
Also, "arg" should probably be a "const"?
Can you please rename "n" to "arg_size" or something similar?
> +{
> + unsigned char *data = arg;
> + unsigned int data_uint = 0;
> +
> + for (unsigned int i = 0; i < n && i < 4; i++) {
Please move the declaration for "i" to the top of the function, for consistency.
Also, why stop at i == 4? Couldn't this function be used for 8-byte
long integers too? It should be up to the caller function to set "n"
correctly.
> + #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> + data_uint |= data[i] << (i * 8);
> + #else
> + data_uint |= data[i] << ((n - i - 1) * 8);
> + #endif
> + }
> +
> + fprintf(f, "%d", data_uint);
> +}
> +
> void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep)
> {
> unsigned char *data = arg;
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> index 0ef373cef4c7..7488ef38e7a9 100644
> --- a/tools/bpf/bpftool/main.h
> +++ b/tools/bpf/bpftool/main.h
> @@ -90,6 +90,7 @@ void __printf(1, 2) p_info(const char *fmt, ...);
>
> bool is_prefix(const char *pfx, const char *str);
> int detect_common_prefix(const char *arg, ...);
> +void fprint_uint(FILE *f, void *arg, unsigned int n);
> void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep);
> void usage(void) __noreturn;
>
> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index aaeb8939e137..638bd8de8135 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -259,8 +259,13 @@ static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,
> }
>
> if (info->value_size) {
> - printf("value:%c", break_names ? '\n' : ' ');
> - fprint_hex(stdout, value, info->value_size, " ");
> + if (map_is_map_of_maps(info->type)) {
> + printf("id:%c", break_names ? '\n' : ' ');
> + fprint_uint(stdout, value, info->value_size);
> + } else {
> + printf("value:%c", break_names ? '\n' : ' ');
> + fprint_hex(stdout, value, info->value_size, " ");
> + }
> }
>
> printf("\n");
> --
> 2.37.1 (Apple Git-137.1)
>
