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bpftool: Use print_entry_error() in case of ENOENT when dumping 

Commit bf598a8f0f ("bpftool: Improve handling of ENOENT on map dumps")
used print_entry_plain() in case of ENOENT. However, that commit 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. Use print_entry_error() to
output the desired message. That function's "value" parameter is also
renamed to indicate that we never use it for an actual map value.

The output format is unchanged.

Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Benjamin Poirier 2019-04-15 16:15:35 +09:00 committed by Daniel Borkmann
parent 25df480def
commit 0478c3bf81
1 changed files with 14 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
tools/bpf/bpftool/map.c
View File

@ -261,20 +261,20 @@ 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 *error_msg)
{
int value_size = strlen(value);
int msg_size = strlen(error_msg);
bool single_line, 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 || msg_size > 16;
single_line = info->key_size + msg_size <= 24 && !break_names;
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", break_names ? '\n' : ' ', error_msg);
printf("\n");
}
@ -298,11 +298,7 @@ static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,
if (info->value_size) {
printf("value:%c", break_names ? '\n' : ' ');
if (value)
fprint_hex(stdout, value, info->value_size,
" ");
else
printf("<no entry>");
fprint_hex(stdout, value, info->value_size, " ");
}
printf("\n");
@ -321,11 +317,8 @@ static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,
for (i = 0; i < n; i++) {
printf("value (CPU %02d):%c",
i, info->value_size > 16 ? '\n' : ' ');
if (value)
fprint_hex(stdout, value + i * step,
info->value_size, " ");
else
printf("<no entry>");
fprint_hex(stdout, value + i * step,
info->value_size, " ");
printf("\n");
}
}
@ -722,11 +715,13 @@ static int dump_map_elem(int fd, void *key, void *value,
jsonw_string_field(json_wtr, "error", strerror(lookup_errno));
jsonw_end_object(json_wtr);
} else {
const char *msg = NULL;
if (errno == ENOENT)
print_entry_plain(map_info, key, NULL);
else
print_entry_error(map_info, key,
strerror(lookup_errno));
msg = "<no entry>";
print_entry_error(map_info, key,
msg ? : strerror(lookup_errno));
}
return 0;