2019-04-12 12:03 UTC+0900 ~ Benjamin Poirier <bpoirier@xxxxxxxx>
Commit bf598a8f0f77 ("bpftool: Improve handling of ENOENT on map dumps")
used print_entry_plain() in case of ENOENT because that function provided
the desired formatting. However, that commit actually introduces dead code.
Per-cpu maps are zero-filled. When reading them, it's all or nothing. There
will never be a case where some cpus have an entry and others don't.
The truth is that ENOENT is an error case. So rework print_entry_error() to
provide the desired formatting.
Note that this commit changes the output format in case of errors other
than ENOENT.
example before:
key:
00 00 00 00
value:
No space left on device
[...]
example after:
key: 00 00 00 00
value:
No space left on device
[...]
The ENOENT case is unchanged:
key: 00 00 00 00 value: 14 5b 00 00 00 00 00 00
key: 01 00 00 00 value: <no entry>
[...]
Signed-off-by: Benjamin Poirier <bpoirier@xxxxxxxx>
---
tools/bpf/bpftool/map.c | 34 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 20 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index e96903078991..71840faaeab5 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -261,20 +261,19 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key,
}
static void print_entry_error(struct bpf_map_info *info, unsigned char *key,
- const char *value)
+ const char *value, bool single_line)
Nit: if you respin the series, could you rename "value" into "error_msg"
or something like this to better indicate we never pass an actual map
value to the function?
{
- int value_size = strlen(value);
- bool single_line, break_names;
+ bool break_names;
- break_names = info->key_size > 16 || value_size > 16;
- single_line = info->key_size + value_size <= 24 && !break_names;
+ break_names = info->key_size > 16;
+ single_line = single_line && !break_names;
If I understand correctly, this will also change formatting when error
message is short (shorter than 16 characters: the "value" line will now
be unconditionally split, even for short error messages (other than "<no
entry>")). Why removing the condition on value_size > 16? (This is just
a remark, I am not against changing it.)
printf("key:%c", break_names ? '\n' : ' ');
fprint_hex(stdout, key, info->key_size, " ");
printf(single_line ? " " : "\n");
- printf("value:%c%s", break_names ? '\n' : ' ', value);
+ printf("value:%c%s", single_line ? ' ' : '\n', value);
printf("\n");
}
[...]
