From 8fe45924387be6b5c1be59a7eb330790c61d5d10 Mon Sep 17 00:00:00 2001 From: Teng Qin Date: Mon, 24 Apr 2017 19:00:37 -0700 Subject: 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 Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- include/trace/events/bpf.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'include/trace') 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 ? " ..." : "") ); -- cgit v1.2.3