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authorPrashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>2018-10-09 10:04:52 +0900
committerAlexei Starovoitov <ast@kernel.org>2018-10-09 21:52:20 -0700
commit8ec92dc22e0e3460cfd29263731c6214d283ea28 (patch)
tree598ac0e74a2f3fdfec9df44b45a3da892bb83837 /tools
parent18a781daa93e67b795976353a6b5d120939c50bc (diff)
tools/bpf: bpftool, print strerror when map lookup error occurs
Since map lookup error can be ENOENT or EOPNOTSUPP, let's print strerror() as error message in normal and JSON output. This patch adds helper function print_entry_error() to print entry from lookup error occurs Example: Following example dumps a map which does not support lookup. Output before: root# bpftool map -jp dump id 40 [ "key": ["0x0a","0x00","0x00","0x00" ], "value": { "error": "can\'t lookup element" }, "key": ["0x0b","0x00","0x00","0x00" ], "value": { "error": "can\'t lookup element" } ] root# bpftool map dump id 40 can't lookup element with key: 0a 00 00 00 can't lookup element with key: 0b 00 00 00 Found 0 elements Output after changes: root# bpftool map dump -jp id 45 [ "key": ["0x0a","0x00","0x00","0x00" ], "value": { "error": "Operation not supported" }, "key": ["0x0b","0x00","0x00","0x00" ], "value": { "error": "Operation not supported" } ] root# bpftool map dump id 45 key: 0a 00 00 00 value: Operation not supported key: 0b 00 00 00 value: Operation not supported Found 0 elements Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/bpf/bpftool/map.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 28d365435fea..9f5de48f8a99 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -336,6 +336,25 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key,
jsonw_end_object(json_wtr);
}
+static void print_entry_error(struct bpf_map_info *info, unsigned char *key,
+ const char *value)
+{
+ int value_size = strlen(value);
+ bool single_line, break_names;
+
+ break_names = info->key_size > 16 || value_size > 16;
+ single_line = info->key_size + value_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("\n");
+}
+
static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,
unsigned char *value)
{
@@ -663,6 +682,7 @@ static int dump_map_elem(int fd, void *key, void *value,
json_writer_t *btf_wtr)
{
int num_elems = 0;
+ int lookup_errno;
if (!bpf_map_lookup_elem(fd, key, value)) {
if (json_output) {
@@ -685,6 +705,8 @@ static int dump_map_elem(int fd, void *key, void *value,
}
/* lookup error handling */
+ lookup_errno = errno;
+
if (map_is_map_of_maps(map_info->type) ||
map_is_map_of_progs(map_info->type))
return 0;
@@ -694,13 +716,10 @@ static int dump_map_elem(int fd, void *key, void *value,
print_hex_data_json(key, map_info->key_size);
jsonw_name(json_wtr, "value");
jsonw_start_object(json_wtr);
- jsonw_string_field(json_wtr, "error",
- "can't lookup element");
+ jsonw_string_field(json_wtr, "error", strerror(lookup_errno));
jsonw_end_object(json_wtr);
} else {
- p_info("can't lookup element with key: ");
- fprint_hex(stderr, key, map_info->key_size, " ");
- fprintf(stderr, "\n");
+ print_entry_error(map_info, key, strerror(lookup_errno));
}
return 0;

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