1 // SPDX-License-Identifier: GPL-2.0-only
2 #define _GNU_SOURCE
3 #include <sched.h>
4 #include <sys/prctl.h>
5 #include <test_progs.h>
6
7 #define MAX_TRAMP_PROGS 38
8
9 struct inst {
10 struct bpf_object *obj;
11 struct bpf_link *link_fentry;
12 struct bpf_link *link_fexit;
13 };
14
test_task_rename(void)15 static int test_task_rename(void)
16 {
17 int fd, duration = 0, err;
18 char buf[] = "test_overhead";
19
20 fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
21 if (CHECK(fd < 0, "open /proc", "err %d", errno))
22 return -1;
23 err = write(fd, buf, sizeof(buf));
24 if (err < 0) {
25 CHECK(err < 0, "task rename", "err %d", errno);
26 close(fd);
27 return -1;
28 }
29 close(fd);
30 return 0;
31 }
32
load(struct bpf_object * obj,const char * name)33 static struct bpf_link *load(struct bpf_object *obj, const char *name)
34 {
35 struct bpf_program *prog;
36 int duration = 0;
37
38 prog = bpf_object__find_program_by_title(obj, name);
39 if (CHECK(!prog, "find_probe", "prog '%s' not found\n", name))
40 return ERR_PTR(-EINVAL);
41 return bpf_program__attach_trace(prog);
42 }
43
44 /* TODO: use different target function to run in concurrent mode */
serial_test_trampoline_count(void)45 void serial_test_trampoline_count(void)
46 {
47 const char *fentry_name = "fentry/__set_task_comm";
48 const char *fexit_name = "fexit/__set_task_comm";
49 const char *object = "test_trampoline_count.o";
50 struct inst inst[MAX_TRAMP_PROGS] = {};
51 int err, i = 0, duration = 0;
52 struct bpf_object *obj;
53 struct bpf_link *link;
54 char comm[16] = {};
55
56 /* attach 'allowed' trampoline programs */
57 for (i = 0; i < MAX_TRAMP_PROGS; i++) {
58 obj = bpf_object__open_file(object, NULL);
59 if (!ASSERT_OK_PTR(obj, "obj_open_file")) {
60 obj = NULL;
61 goto cleanup;
62 }
63
64 err = bpf_object__load(obj);
65 if (CHECK(err, "obj_load", "err %d\n", err))
66 goto cleanup;
67 inst[i].obj = obj;
68 obj = NULL;
69
70 if (rand() % 2) {
71 link = load(inst[i].obj, fentry_name);
72 if (!ASSERT_OK_PTR(link, "attach_prog")) {
73 link = NULL;
74 goto cleanup;
75 }
76 inst[i].link_fentry = link;
77 } else {
78 link = load(inst[i].obj, fexit_name);
79 if (!ASSERT_OK_PTR(link, "attach_prog")) {
80 link = NULL;
81 goto cleanup;
82 }
83 inst[i].link_fexit = link;
84 }
85 }
86
87 /* and try 1 extra.. */
88 obj = bpf_object__open_file(object, NULL);
89 if (!ASSERT_OK_PTR(obj, "obj_open_file")) {
90 obj = NULL;
91 goto cleanup;
92 }
93
94 err = bpf_object__load(obj);
95 if (CHECK(err, "obj_load", "err %d\n", err))
96 goto cleanup_extra;
97
98 /* ..that needs to fail */
99 link = load(obj, fentry_name);
100 err = libbpf_get_error(link);
101 if (!ASSERT_ERR_PTR(link, "cannot attach over the limit")) {
102 bpf_link__destroy(link);
103 goto cleanup_extra;
104 }
105
106 /* with E2BIG error */
107 ASSERT_EQ(err, -E2BIG, "proper error check");
108 ASSERT_EQ(link, NULL, "ptr_is_null");
109
110 /* and finaly execute the probe */
111 if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
112 goto cleanup_extra;
113 CHECK_FAIL(test_task_rename());
114 CHECK_FAIL(prctl(PR_SET_NAME, comm, 0L, 0L, 0L));
115
116 cleanup_extra:
117 bpf_object__close(obj);
118 cleanup:
119 if (i >= MAX_TRAMP_PROGS)
120 i = MAX_TRAMP_PROGS - 1;
121 for (; i >= 0; i--) {
122 bpf_link__destroy(inst[i].link_fentry);
123 bpf_link__destroy(inst[i].link_fexit);
124 bpf_object__close(inst[i].obj);
125 }
126 }
127