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Subject[RFC PATCH 01/13] bpf tools: Add map related BPF helper
Date
Add BPF map helpers so user can read from bpf map in user space.
Following commits will introduce user space BPF, bpf_map will be
used to pass information between kernel and user BPF programs.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
---
tools/lib/bpf/bpf.c | 24 ++++++++++++++++++++++++
tools/lib/bpf/bpf.h | 2 ++
2 files changed, 26 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 1f91cc9..337d9dc 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -97,3 +97,27 @@ int bpf_map_update_elem(int fd, void *key, void *value,

return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}
+
+int bpf_map_lookup_elem(int fd, void *key, void *value)
+{
+ union bpf_attr attr;
+
+ bzero(&attr, sizeof(attr));
+ attr.map_fd = fd;
+ attr.key = ptr_to_u64(key);
+ attr.value = ptr_to_u64(value);
+
+ return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+}
+
+int bpf_map_get_next_key(int fd, void *key, void *next_key)
+{
+ union bpf_attr attr;
+
+ bzero(&attr, sizeof(attr));
+ attr.map_fd = fd;
+ attr.key = ptr_to_u64(key);
+ attr.next_key = ptr_to_u64(next_key);
+
+ return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index a764655..c06ea21 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -22,4 +22,6 @@ int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,

int bpf_map_update_elem(int fd, void *key, void *value,
u64 flags);
+int bpf_map_lookup_elem(int fd, void *key, void *value);
+int bpf_map_get_next_key(int fd, void *key, void *next_key);
#endif
--
1.8.3.4
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