[PATCH bpf-next 0/2] bpftool: Fix some json formatting for struct_ops

[PATCH bpf-next 0/2] bpftool: Fix some json formatting for struct_ops

[Manu Bretelle]

When dumping struct_ops with bpftool, the json produced was invalid.
1) pointer values where not printed with surrounding quotes, causing an
invalid json integer to be emitted
2) when bpftool struct_ops dump id <id>, the 2 dictionaries were not
wrapped in a array, here also causing an invalid json payload to be
emitted. 

Manu Bretelle (2):
  bpftool: fix printing of pointer value
  bpftool: wrap struct_ops dump in an array

 tools/bpf/bpftool/btf_dumper.c | 2 +-
 tools/bpf/bpftool/struct_ops.c | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

-- 
2.39.3

[PATCH bpf-next 1/2] bpftool: fix printing of pointer value

[Manu Bretelle]

When printing a pointer value, "%p" will either print the hexadecimal
value of the pointer (e.g `0x1234`), or `(nil)` when NULL.

Both of those are invalid json "integer" values and need to be wrapped
in quotes.

Before:
```
$ sudo bpftool struct_ops dump  name ned_dummy_cca | grep next
                    "next": (nil),
$ sudo bpftool struct_ops dump  name ned_dummy_cca | \
    jq '.[1].bpf_struct_ops_tcp_congestion_ops.data.list.next'
parse error: Invalid numeric literal at line 29, column 34
```

After:
```
$ sudo ./bpftool struct_ops dump  name ned_dummy_cca | grep next
                    "next": "(nil)",
$ sudo ./bpftool struct_ops dump  name ned_dummy_cca | \
    jq '.[1].bpf_struct_ops_tcp_congestion_ops.data.list.next'
"(nil)"
```

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
---
 tools/bpf/bpftool/btf_dumper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index 1b7f69714604..527fe867a8fb 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -127,7 +127,7 @@ static void btf_dumper_ptr(const struct btf_dumper *d,
 
 print_ptr_value:
 	if (d->is_plain_text)
-		jsonw_printf(d->jw, "%p", (void *)value);
+		jsonw_printf(d->jw, "\"%p\"", (void *)value);
 	else
 		jsonw_printf(d->jw, "%lu", value);
 }
-- 
2.39.3

[PATCH bpf-next 2/2] bpftool: wrap struct_ops dump in an array

[Manu Bretelle]

When dumping a struct_ops, 2 dictionaries are emitted.

When using `name`, they were already wrapped in an array, but not when
using `id`. Causing `jq` to fail at parsing the payload as it reached
the comma following the first dict.

This change wraps those dictionaries in an array so valid json is
emitted.

Before, jq fails to parse the output:
```
 $ sudo bpftool struct_ops dump id 1523612 | jq . > /dev/null
parse error: Expected value before ',' at line 19, column 2
```

After, no error parsing the output:
```
sudo ./bpftool  struct_ops dump id 1523612 | jq . > /dev/null
```

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
---
 tools/bpf/bpftool/struct_ops.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c
index 3ebc9fe91e0e..d573f2640d8e 100644
--- a/tools/bpf/bpftool/struct_ops.c
+++ b/tools/bpf/bpftool/struct_ops.c
@@ -276,6 +276,9 @@ static struct res do_one_id(const char *id_str, work_func func, void *data,
 
 	res.nr_maps++;
 
+	if (wtr)
+		jsonw_start_array(wtr);
+
 	if (func(fd, info, data, wtr))
 		res.nr_errs++;
 	else if (!wtr && json_output)
@@ -288,6 +291,9 @@ static struct res do_one_id(const char *id_str, work_func func, void *data,
 		 */
 		jsonw_null(json_wtr);
 
+	if (wtr)
+		jsonw_end_array(wtr);
+
 done:
 	free(info);
 	close(fd);
-- 
2.39.3

Re: [PATCH bpf-next 0/2] bpftool: Fix some json formatting for struct_ops

[Eduard Zingerman]

On Wed, 2023-10-18 at 16:01 -0700, Manu Bretelle wrote:
> When dumping struct_ops with bpftool, the json produced was invalid.
> 1) pointer values where not printed with surrounding quotes, causing an
> invalid json integer to be emitted
> 2) when bpftool struct_ops dump id <id>, the 2 dictionaries were not
> wrapped in a array, here also causing an invalid json payload to be
> emitted. 

Acked-by: Eduard Zingerman <eddyz87@gmail.com>

Hi Manu,

I've tested this patch-set and everything seems to work as expected.

Thanks,
Eduard

> Manu Bretelle (2):
>   bpftool: fix printing of pointer value
>   bpftool: wrap struct_ops dump in an array
> 
>  tools/bpf/bpftool/btf_dumper.c | 2 +-
>  tools/bpf/bpftool/struct_ops.c | 6 ++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 

Re: [PATCH bpf-next 0/2] bpftool: Fix some json formatting for struct_ops

[Quentin Monnet]

On 19/10/2023 00:01, Manu Bretelle wrote:
> When dumping struct_ops with bpftool, the json produced was invalid.
> 1) pointer values where not printed with surrounding quotes, causing an
> invalid json integer to be emitted
> 2) when bpftool struct_ops dump id <id>, the 2 dictionaries were not
> wrapped in a array, here also causing an invalid json payload to be
> emitted. 
> 
> Manu Bretelle (2):
>   bpftool: fix printing of pointer value
>   bpftool: wrap struct_ops dump in an array
> 
>  tools/bpf/bpftool/btf_dumper.c | 2 +-
>  tools/bpf/bpftool/struct_ops.c | 6 ++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 

Acked-by: Quentin Monnet <quentin@isovalent.com>

Thanks a lot for these fixes!

Re: [PATCH bpf-next 0/2] bpftool: Fix some json formatting for struct_ops

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Wed, 18 Oct 2023 16:01:31 -0700 you wrote:
> When dumping struct_ops with bpftool, the json produced was invalid.
> 1) pointer values where not printed with surrounding quotes, causing an
> invalid json integer to be emitted
> 2) when bpftool struct_ops dump id <id>, the 2 dictionaries were not
> wrapped in a array, here also causing an invalid json payload to be
> emitted.
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/2] bpftool: fix printing of pointer value
    https://git.kernel.org/bpf/bpf-next/c/90704b4be0b0
  - [bpf-next,2/2] bpftool: wrap struct_ops dump in an array
    https://git.kernel.org/bpf/bpf-next/c/6bd5e167af2e

You are awesome, thank you!
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