1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
3 #include "test_attach_probe.skel.h"
4 
5 /* this is how USDT semaphore is actually defined, except volatile modifier */
6 volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes")));
7 
8 /* uprobe attach point */
9 static noinline void trigger_func(void)
10 {
11 	asm volatile ("");
12 }
13 
14 /* attach point for byname uprobe */
15 static noinline void trigger_func2(void)
16 {
17 	asm volatile ("");
18 }
19 
20 /* attach point for byname sleepable uprobe */
21 static noinline void trigger_func3(void)
22 {
23 	asm volatile ("");
24 }
25 
26 static char test_data[] = "test_data";
27 
28 void test_attach_probe(void)
29 {
30 	DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
31 	struct bpf_link *kprobe_link, *kretprobe_link;
32 	struct bpf_link *uprobe_link, *uretprobe_link;
33 	struct test_attach_probe* skel;
34 	ssize_t uprobe_offset, ref_ctr_offset;
35 	struct bpf_link *uprobe_err_link;
36 	bool legacy;
37 	char *mem;
38 
39 	/* Check if new-style kprobe/uprobe API is supported.
40 	 * Kernels that support new FD-based kprobe and uprobe BPF attachment
41 	 * through perf_event_open() syscall expose
42 	 * /sys/bus/event_source/devices/kprobe/type and
43 	 * /sys/bus/event_source/devices/uprobe/type files, respectively. They
44 	 * contain magic numbers that are passed as "type" field of
45 	 * perf_event_attr. Lack of such file in the system indicates legacy
46 	 * kernel with old-style kprobe/uprobe attach interface through
47 	 * creating per-probe event through tracefs. For such cases
48 	 * ref_ctr_offset feature is not supported, so we don't test it.
49 	 */
50 	legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0;
51 
52 	uprobe_offset = get_uprobe_offset(&trigger_func);
53 	if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset"))
54 		return;
55 
56 	ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
57 	if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
58 		return;
59 
60 	skel = test_attach_probe__open();
61 	if (!ASSERT_OK_PTR(skel, "skel_open"))
62 		return;
63 
64 	/* sleepable kprobe test case needs flags set before loading */
65 	if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable,
66 		BPF_F_SLEEPABLE), "kprobe_sleepable_flags"))
67 		goto cleanup;
68 
69 	if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load"))
70 		goto cleanup;
71 	if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
72 		goto cleanup;
73 
74 	/* manual-attach kprobe/kretprobe */
75 	kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
76 						 false /* retprobe */,
77 						 SYS_NANOSLEEP_KPROBE_NAME);
78 	if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
79 		goto cleanup;
80 	skel->links.handle_kprobe = kprobe_link;
81 
82 	kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe,
83 						    true /* retprobe */,
84 						    SYS_NANOSLEEP_KPROBE_NAME);
85 	if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe"))
86 		goto cleanup;
87 	skel->links.handle_kretprobe = kretprobe_link;
88 
89 	/* auto-attachable kprobe and kretprobe */
90 	skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto);
91 	ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto");
92 
93 	skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto);
94 	ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto");
95 
96 	if (!legacy)
97 		ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before");
98 
99 	uprobe_opts.retprobe = false;
100 	uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
101 	uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe,
102 						      0 /* self pid */,
103 						      "/proc/self/exe",
104 						      uprobe_offset,
105 						      &uprobe_opts);
106 	if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe"))
107 		goto cleanup;
108 	skel->links.handle_uprobe = uprobe_link;
109 
110 	if (!legacy)
111 		ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after");
112 
113 	/* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */
114 	uprobe_opts.retprobe = true;
115 	uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
116 	uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe,
117 							 -1 /* any pid */,
118 							 "/proc/self/exe",
119 							 uprobe_offset, &uprobe_opts);
120 	if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe"))
121 		goto cleanup;
122 	skel->links.handle_uretprobe = uretprobe_link;
123 
124 	/* verify auto-attach fails for old-style uprobe definition */
125 	uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);
126 	if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,
127 		       "auto-attach should fail for old-style name"))
128 		goto cleanup;
129 
130 	uprobe_opts.func_name = "trigger_func2";
131 	uprobe_opts.retprobe = false;
132 	uprobe_opts.ref_ctr_offset = 0;
133 	skel->links.handle_uprobe_byname =
134 			bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname,
135 							0 /* this pid */,
136 							"/proc/self/exe",
137 							0, &uprobe_opts);
138 	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname"))
139 		goto cleanup;
140 
141 	/* verify auto-attach works */
142 	skel->links.handle_uretprobe_byname =
143 			bpf_program__attach(skel->progs.handle_uretprobe_byname);
144 	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname"))
145 		goto cleanup;
146 
147 	/* test attach by name for a library function, using the library
148 	 * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo().
149 	 */
150 	uprobe_opts.func_name = "malloc";
151 	uprobe_opts.retprobe = false;
152 	skel->links.handle_uprobe_byname2 =
153 			bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2,
154 							0 /* this pid */,
155 							"libc.so.6",
156 							0, &uprobe_opts);
157 	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2"))
158 		goto cleanup;
159 
160 	uprobe_opts.func_name = "free";
161 	uprobe_opts.retprobe = true;
162 	skel->links.handle_uretprobe_byname2 =
163 			bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2,
164 							-1 /* any pid */,
165 							"libc.so.6",
166 							0, &uprobe_opts);
167 	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2"))
168 		goto cleanup;
169 
170 	/* sleepable kprobes should not attach successfully */
171 	skel->links.handle_kprobe_sleepable = bpf_program__attach(skel->progs.handle_kprobe_sleepable);
172 	if (!ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable"))
173 		goto cleanup;
174 
175 	/* test sleepable uprobe and uretprobe variants */
176 	skel->links.handle_uprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uprobe_byname3_sleepable);
177 	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3_sleepable, "attach_uprobe_byname3_sleepable"))
178 		goto cleanup;
179 
180 	skel->links.handle_uprobe_byname3 = bpf_program__attach(skel->progs.handle_uprobe_byname3);
181 	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3, "attach_uprobe_byname3"))
182 		goto cleanup;
183 
184 	skel->links.handle_uretprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uretprobe_byname3_sleepable);
185 	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3_sleepable, "attach_uretprobe_byname3_sleepable"))
186 		goto cleanup;
187 
188 	skel->links.handle_uretprobe_byname3 = bpf_program__attach(skel->progs.handle_uretprobe_byname3);
189 	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3, "attach_uretprobe_byname3"))
190 		goto cleanup;
191 
192 	skel->bss->user_ptr = test_data;
193 
194 	/* trigger & validate kprobe && kretprobe */
195 	usleep(1);
196 
197 	/* trigger & validate shared library u[ret]probes attached by name */
198 	mem = malloc(1);
199 	free(mem);
200 
201 	/* trigger & validate uprobe & uretprobe */
202 	trigger_func();
203 
204 	/* trigger & validate uprobe attached by name */
205 	trigger_func2();
206 
207 	/* trigger & validate sleepable uprobe attached by name */
208 	trigger_func3();
209 
210 	ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
211 	ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res");
212 	ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
213 	ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res");
214 	ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");
215 	ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");
216 	ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");
217 	ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");
218 	ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");
219 	ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");
220 	ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
221 	ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
222 	ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
223 	ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
224 
225 cleanup:
226 	test_attach_probe__destroy(skel);
227 	ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_cleanup");
228 }
229