1 #include <linux/blkdev.h>
2 #include <uapi/linux/ptrace.h>
3
4 /**
5 * @brief Helper method to filter based on the specified inputString.
6 * @param inputString The operation input string to check against the filter.
7 * @return True if the specified inputString starts with the hard-coded FILTER_STRING; otherwise, false.
8 */
filter(char const * inputString)9 static inline bool filter(char const* inputString)
10 {
11 char needle[] = "FILTER_STRING"; ///< The FILTER STRING is replaced by python code.
12 char haystack[sizeof(needle)] = {};
13 bpf_probe_read(&haystack, sizeof(haystack), (void*)inputString);
14 for (int i = 0; i < sizeof(needle) - 1; ++i) {
15 if (needle[i] != haystack[i]) {
16 return false;
17 }
18 }
19 return true;
20 }
21
22 /**
23 * @brief Contains the operation start data to trace.
24 */
25 struct start_data_t
26 {
27 u64 operation_id; ///< The id of the operation.
28 char input[64]; ///< The input string of the request.
29 u64 start; ///< Timestamp of the start operation (start timestamp).
30 };
31
32 /**
33 * @brief Contains the operation start data.
34 * key: the operation id.
35 * value: The operation start latency data.
36 */
37 BPF_HASH(start_hash, u64, struct start_data_t);
38
39 /**
40 * @brief Reads the operation request arguments and stores the start data in the hash.
41 * @param ctx The BPF context.
42 */
trace_operation_start(struct pt_regs * ctx)43 int trace_operation_start(struct pt_regs* ctx)
44 {
45 struct start_data_t start_data = {};
46 bpf_usdt_readarg_p(2, ctx, &start_data.input, sizeof(start_data.input));
47
48 FILTER ///< Replaced by python code.
49
50 bpf_usdt_readarg(1, ctx, &start_data.operation_id);
51
52 start_data.start = bpf_ktime_get_ns();
53 start_hash.update(&start_data.operation_id, &start_data);
54 return 0;
55 }
56