bpf: add selftest for stackmap with BPF_F_STACK_BUILD_ID

test_stacktrace_build_id() is added. It accesses tracepoint urandom_read
with "dd" and "urandom_read" and gathers stack traces. Then it reads the
stack traces from the stackmap.

urandom_read is a statically link binary that reads from /dev/urandom.
test_stacktrace_build_id() calls readelf to read build ID of urandom_read
and compares it with build ID from the stackmap.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Song Liu
2018-03-14 10:23:22 -07:00
committed by Daniel Borkmann
parent 615755a77b
commit 81f77fd0de
5 changed files with 278 additions and 2 deletions

View File

@@ -231,6 +231,28 @@ enum bpf_attach_type {
#define BPF_F_RDONLY (1U << 3)
#define BPF_F_WRONLY (1U << 4)
/* Flag for stack_map, store build_id+offset instead of pointer */
#define BPF_F_STACK_BUILD_ID (1U << 5)
enum bpf_stack_build_id_status {
/* user space need an empty entry to identify end of a trace */
BPF_STACK_BUILD_ID_EMPTY = 0,
/* with valid build_id and offset */
BPF_STACK_BUILD_ID_VALID = 1,
/* couldn't get build_id, fallback to ip */
BPF_STACK_BUILD_ID_IP = 2,
};
#define BPF_BUILD_ID_SIZE 20
struct bpf_stack_build_id {
__s32 status;
unsigned char build_id[BPF_BUILD_ID_SIZE];
union {
__u64 offset;
__u64 ip;
};
};
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */