1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
 3#include <vmlinux.h>
 4#include <bpf/bpf_helpers.h>
 5#include <bpf/bpf_tracing.h>
 6#include <bpf/usdt.bpf.h>
 7
 8char _license[] SEC("license") = "GPL";
 9
10__u64 entry_stack1[32], exit_stack1[32];
11__u64 entry_stack1_recur[32], exit_stack1_recur[32];
12__u64 entry_stack2[32];
13__u64 entry_stack3[32];
14__u64 entry_stack4[32], exit_stack4[32];
15__u64 usdt_stack[32];
16
17int entry1_len, exit1_len;
18int entry1_recur_len, exit1_recur_len;
19int entry2_len, exit2_len;
20int entry3_len, exit3_len;
21int entry4_len, exit4_len;
22int usdt_len;
23
24#define SZ sizeof(usdt_stack)
25
26SEC("uprobe//proc/self/exe:target_1")
27int BPF_UPROBE(uprobe_1)
28{
29	/* target_1 is recursive wit depth of 2, so we capture two separate
30	 * stack traces, depending on which occurence it is
31	 */
32	static bool recur = false;
33
34	if (!recur)
35		entry1_len = bpf_get_stack(ctx, &entry_stack1, SZ, BPF_F_USER_STACK);
36	else
37		entry1_recur_len = bpf_get_stack(ctx, &entry_stack1_recur, SZ, BPF_F_USER_STACK);
38
39	recur = true;
40	return 0;
41}
42
43SEC("uretprobe//proc/self/exe:target_1")
44int BPF_URETPROBE(uretprobe_1)
45{
46	/* see above, target_1 is recursive */
47	static bool recur = false;
48
49	/* NOTE: order of returns is reversed to order of entries */
50	if (!recur)
51		exit1_recur_len = bpf_get_stack(ctx, &exit_stack1_recur, SZ, BPF_F_USER_STACK);
52	else
53		exit1_len = bpf_get_stack(ctx, &exit_stack1, SZ, BPF_F_USER_STACK);
54
55	recur = true;
56	return 0;
57}
58
59SEC("uprobe//proc/self/exe:target_2")
60int BPF_UPROBE(uprobe_2)
61{
62	entry2_len = bpf_get_stack(ctx, &entry_stack2, SZ, BPF_F_USER_STACK);
63	return 0;
64}
65
66/* no uretprobe for target_2 */
67
68SEC("uprobe//proc/self/exe:target_3")
69int BPF_UPROBE(uprobe_3)
70{
71	entry3_len = bpf_get_stack(ctx, &entry_stack3, SZ, BPF_F_USER_STACK);
72	return 0;
73}
74
75/* no uretprobe for target_3 */
76
77SEC("uprobe//proc/self/exe:target_4")
78int BPF_UPROBE(uprobe_4)
79{
80	entry4_len = bpf_get_stack(ctx, &entry_stack4, SZ, BPF_F_USER_STACK);
81	return 0;
82}
83
84SEC("uretprobe//proc/self/exe:target_4")
85int BPF_URETPROBE(uretprobe_4)
86{
87	exit4_len = bpf_get_stack(ctx, &exit_stack4, SZ, BPF_F_USER_STACK);
88	return 0;
89}
90
91SEC("usdt//proc/self/exe:uretprobe_stack:target")
92int BPF_USDT(usdt_probe)
93{
94	usdt_len = bpf_get_stack(ctx, &usdt_stack, SZ, BPF_F_USER_STACK);
95	return 0;
96}