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authorTeng Qin <qinteng@fb.com>2017-04-24 19:00:37 -0700
committerDavid S. Miller <davem@davemloft.net>2017-04-25 11:57:45 -0400
commit8fe45924387be6b5c1be59a7eb330790c61d5d10 (patch)
tree1879f4fd4d14907155b1ebb2fd85ff26aa89ebbe /include/trace
parent472ecf084a7687347f79720c83881c07407bfd8b (diff)
downloadlinux-8fe45924387be6b5c1be59a7eb330790c61d5d10.tar.bz2
bpf: map_get_next_key to return first key on NULL
When iterating through a map, we need to find a key that does not exist in the map so map_get_next_key will give us the first key of the map. This often requires a lot of guessing in production systems. This patch makes map_get_next_key return the first key when the key pointer in the parameter is NULL. Signed-off-by: Teng Qin <qinteng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/bpf.h10
1 files changed, 7 insertions, 3 deletions
diff --git a/include/trace/events/bpf.h b/include/trace/events/bpf.h
index c3a53fd47ff1..52c8425d144b 100644
--- a/include/trace/events/bpf.h
+++ b/include/trace/events/bpf.h
@@ -321,11 +321,14 @@ TRACE_EVENT(bpf_map_next_key,
__dynamic_array(u8, key, map->key_size)
__dynamic_array(u8, nxt, map->key_size)
__field(bool, key_trunc)
+ __field(bool, key_null)
__field(int, ufd)
),
TP_fast_assign(
- memcpy(__get_dynamic_array(key), key, map->key_size);
+ if (key)
+ memcpy(__get_dynamic_array(key), key, map->key_size);
+ __entry->key_null = !key;
memcpy(__get_dynamic_array(nxt), key_next, map->key_size);
__entry->type = map->map_type;
__entry->key_len = min(map->key_size, 16U);
@@ -336,8 +339,9 @@ TRACE_EVENT(bpf_map_next_key,
TP_printk("map type=%s ufd=%d key=[%s%s] next=[%s%s]",
__print_symbolic(__entry->type, __MAP_TYPE_SYM_TAB),
__entry->ufd,
- __print_hex(__get_dynamic_array(key), __entry->key_len),
- __entry->key_trunc ? " ..." : "",
+ __entry->key_null ? "NULL" : __print_hex(__get_dynamic_array(key),
+ __entry->key_len),
+ __entry->key_trunc && !__entry->key_null ? " ..." : "",
__print_hex(__get_dynamic_array(nxt), __entry->key_len),
__entry->key_trunc ? " ..." : "")
);