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 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 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 void test_trampoline_count(void) 45 { 46 const char *fentry_name = "fentry/__set_task_comm"; 47 const char *fexit_name = "fexit/__set_task_comm"; 48 const char *object = "test_trampoline_count.o"; 49 struct inst inst[MAX_TRAMP_PROGS] = {}; 50 int err, i = 0, duration = 0; 51 struct bpf_object *obj; 52 struct bpf_link *link; 53 char comm[16] = {}; 54 55 /* attach 'allowed' trampoline programs */ 56 for (i = 0; i < MAX_TRAMP_PROGS; i++) { 57 obj = bpf_object__open_file(object, NULL); 58 if (!ASSERT_OK_PTR(obj, "obj_open_file")) { 59 obj = NULL; 60 goto cleanup; 61 } 62 63 err = bpf_object__load(obj); 64 if (CHECK(err, "obj_load", "err %d\n", err)) 65 goto cleanup; 66 inst[i].obj = obj; 67 obj = NULL; 68 69 if (rand() % 2) { 70 link = load(inst[i].obj, fentry_name); 71 if (!ASSERT_OK_PTR(link, "attach_prog")) { 72 link = NULL; 73 goto cleanup; 74 } 75 inst[i].link_fentry = link; 76 } else { 77 link = load(inst[i].obj, fexit_name); 78 if (!ASSERT_OK_PTR(link, "attach_prog")) { 79 link = NULL; 80 goto cleanup; 81 } 82 inst[i].link_fexit = link; 83 } 84 } 85 86 /* and try 1 extra.. */ 87 obj = bpf_object__open_file(object, NULL); 88 if (!ASSERT_OK_PTR(obj, "obj_open_file")) { 89 obj = NULL; 90 goto cleanup; 91 } 92 93 err = bpf_object__load(obj); 94 if (CHECK(err, "obj_load", "err %d\n", err)) 95 goto cleanup_extra; 96 97 /* ..that needs to fail */ 98 link = load(obj, fentry_name); 99 err = libbpf_get_error(link); 100 if (!ASSERT_ERR_PTR(link, "cannot attach over the limit")) { 101 bpf_link__destroy(link); 102 goto cleanup_extra; 103 } 104 105 /* with E2BIG error */ 106 ASSERT_EQ(err, -E2BIG, "proper error check"); 107 ASSERT_EQ(link, NULL, "ptr_is_null"); 108 109 /* and finaly execute the probe */ 110 if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L))) 111 goto cleanup_extra; 112 CHECK_FAIL(test_task_rename()); 113 CHECK_FAIL(prctl(PR_SET_NAME, comm, 0L, 0L, 0L)); 114 115 cleanup_extra: 116 bpf_object__close(obj); 117 cleanup: 118 if (i >= MAX_TRAMP_PROGS) 119 i = MAX_TRAMP_PROGS - 1; 120 for (; i >= 0; i--) { 121 bpf_link__destroy(inst[i].link_fentry); 122 bpf_link__destroy(inst[i].link_fexit); 123 bpf_object__close(inst[i].obj); 124 } 125 } 126