When using `bpftool map dump` with map_of_maps, it is usually
more convenient to show the inner map id instead of raw value.
We are changing the plain print behavior to show inner_map_id
instead of hex value, this would help with quick look up of
inner map with `bpftool map dump id <inner_map_id>`.
To avoid disrupting scripted behavior, we will add a new
`inner_map_id` field to json output instead of replacing value.
plain print:
```
$ bpftool map dump id 138
Without Patch:
key:
fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05
27 16 06 00
value:
8b 00 00 00
Found 1 element
With Patch:
key:
fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05
27 16 06 00
inner_map_id:
139
Found 1 element
```
json print:
```
$ bpftool -p map dump id 567
Without Patch:
[{
"key": ["0xc0","0x00","0x02","0x05","0x27","0x16","0x06","0x00"
],
"value": ["0x38","0x02","0x00","0x00"
]
}
]
With Patch:
[{
"key": ["0xc0","0x00","0x02","0x05","0x27","0x16","0x06","0x00"
],
"value": ["0x38","0x02","0x00","0x00"
],
"inner_map_id": 568
}
]
```
Signed-off-by: Xueming Feng <[email protected]>
---
Changes in v3:
- In plain print, use printf() directly since inner map id is always a 32bit int.
- Remove unused print_uint() function.
- Rename `id` to `inner_map_id` in plain print output for clearness.
- Add a new `inner_map_id` field to json output.
- Add example output to commit message.
Changes in v2:
- Fix commit message grammar.
- Change `print_uint` to only print to stdout, make `arg` const,
and rename `n` to `arg_size`.
- Make `print_uint` able to take any size of argument up to `unsigned long`,
and print it as unsigned decimal.
Sorry for taking this long, my compiling machine is acting weird. And thanks for
the reviews and suggestions!
tools/bpf/bpftool/map.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index aaeb8939e137..afcd8455db74 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -139,6 +139,10 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key,
print_hex_data_json(key, info->key_size);
jsonw_name(json_wtr, "value");
print_hex_data_json(value, info->value_size);
+ if (map_is_map_of_maps(info->type)) {
+ jsonw_uint_field(json_wtr, "inner_map_id",
+ *(unsigned int *)value);
+ }
if (btf) {
struct btf_dumper d = {
.btf = btf,
@@ -259,8 +263,13 @@ 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("inner_map_id:%c", break_names ? '\n' : ' ');
+ printf("%u ", *(unsigned int *)value);
+ } else {
+ printf("value:%c", break_names ? '\n' : ' ');
+ fprint_hex(stdout, value, info->value_size, " ");
+ }
}
printf("\n");
--
2.37.1 (Apple Git-137.1)
On 4/26/23 9:19 PM, Xueming Feng wrote:
> When using `bpftool map dump` with map_of_maps, it is usually
> more convenient to show the inner map id instead of raw value.
>
> We are changing the plain print behavior to show inner_map_id
> instead of hex value, this would help with quick look up of
> inner map with `bpftool map dump id <inner_map_id>`.
> To avoid disrupting scripted behavior, we will add a new
> `inner_map_id` field to json output instead of replacing value.
>
> plain print:
> ```
> $ bpftool map dump id 138
>
> Without Patch:
> key:
> fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05
> 27 16 06 00
> value:
> 8b 00 00 00
> Found 1 element
>
> With Patch:
> key:
> fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05
> 27 16 06 00
> inner_map_id:
> 139
> Found 1 element
> ```
>
> json print:
> ```
> $ bpftool -p map dump id 567
>
> Without Patch:
> [{
> "key": ["0xc0","0x00","0x02","0x05","0x27","0x16","0x06","0x00"
> ],
> "value": ["0x38","0x02","0x00","0x00"
> ]
> }
> ]
>
> With Patch:
> [{
> "key": ["0xc0","0x00","0x02","0x05","0x27","0x16","0x06","0x00"
> ],
> "value": ["0x38","0x02","0x00","0x00"
> ],
> "inner_map_id": 568
> }
> ]
> ```
>
> Signed-off-by: Xueming Feng <[email protected]>
Ack with a small nit below.
Acked-by: Yonghong Song <[email protected]>
> ---
>
> Changes in v3:
> - In plain print, use printf() directly since inner map id is always a 32bit int.
> - Remove unused print_uint() function.
> - Rename `id` to `inner_map_id` in plain print output for clearness.
> - Add a new `inner_map_id` field to json output.
> - Add example output to commit message.
>
> Changes in v2:
> - Fix commit message grammar.
> - Change `print_uint` to only print to stdout, make `arg` const,
> and rename `n` to `arg_size`.
> - Make `print_uint` able to take any size of argument up to `unsigned long`,
> and print it as unsigned decimal.
>
> Sorry for taking this long, my compiling machine is acting weird. And thanks for
> the reviews and suggestions!
>
> tools/bpf/bpftool/map.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index aaeb8939e137..afcd8455db74 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -139,6 +139,10 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key,
> print_hex_data_json(key, info->key_size);
> jsonw_name(json_wtr, "value");
> print_hex_data_json(value, info->value_size);
> + if (map_is_map_of_maps(info->type)) {
> + jsonw_uint_field(json_wtr, "inner_map_id",
> + *(unsigned int *)value);
> + }
There is only statement under 'if' condition. The above
parenthesis ('{}') is not needed.
> if (btf) {
> struct btf_dumper d = {
> .btf = btf,
> @@ -259,8 +263,13 @@ 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("inner_map_id:%c", break_names ? '\n' : ' ');
> + printf("%u ", *(unsigned int *)value);
> + } else {
> + printf("value:%c", break_names ? '\n' : ' ');
> + fprint_hex(stdout, value, info->value_size, " ");
> + }
> }
>
> printf("\n");