attach_probe.c (6569B)
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 */ 6volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes"))); 7 8/* uprobe attach point */ 9static void trigger_func(void) 10{ 11 asm volatile (""); 12} 13 14/* attach point for byname uprobe */ 15static void trigger_func2(void) 16{ 17 asm volatile (""); 18} 19 20void test_attach_probe(void) 21{ 22 DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); 23 struct bpf_link *kprobe_link, *kretprobe_link; 24 struct bpf_link *uprobe_link, *uretprobe_link; 25 struct test_attach_probe* skel; 26 ssize_t uprobe_offset, ref_ctr_offset; 27 struct bpf_link *uprobe_err_link; 28 bool legacy; 29 char *mem; 30 31 /* Check if new-style kprobe/uprobe API is supported. 32 * Kernels that support new FD-based kprobe and uprobe BPF attachment 33 * through perf_event_open() syscall expose 34 * /sys/bus/event_source/devices/kprobe/type and 35 * /sys/bus/event_source/devices/uprobe/type files, respectively. They 36 * contain magic numbers that are passed as "type" field of 37 * perf_event_attr. Lack of such file in the system indicates legacy 38 * kernel with old-style kprobe/uprobe attach interface through 39 * creating per-probe event through tracefs. For such cases 40 * ref_ctr_offset feature is not supported, so we don't test it. 41 */ 42 legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0; 43 44 uprobe_offset = get_uprobe_offset(&trigger_func); 45 if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset")) 46 return; 47 48 ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr); 49 if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset")) 50 return; 51 52 skel = test_attach_probe__open_and_load(); 53 if (!ASSERT_OK_PTR(skel, "skel_open")) 54 return; 55 if (!ASSERT_OK_PTR(skel->bss, "check_bss")) 56 goto cleanup; 57 58 /* manual-attach kprobe/kretprobe */ 59 kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe, 60 false /* retprobe */, 61 SYS_NANOSLEEP_KPROBE_NAME); 62 if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe")) 63 goto cleanup; 64 skel->links.handle_kprobe = kprobe_link; 65 66 kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe, 67 true /* retprobe */, 68 SYS_NANOSLEEP_KPROBE_NAME); 69 if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe")) 70 goto cleanup; 71 skel->links.handle_kretprobe = kretprobe_link; 72 73 /* auto-attachable kprobe and kretprobe */ 74 skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto); 75 ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto"); 76 77 skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto); 78 ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto"); 79 80 if (!legacy) 81 ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before"); 82 83 uprobe_opts.retprobe = false; 84 uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; 85 uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe, 86 0 /* self pid */, 87 "/proc/self/exe", 88 uprobe_offset, 89 &uprobe_opts); 90 if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe")) 91 goto cleanup; 92 skel->links.handle_uprobe = uprobe_link; 93 94 if (!legacy) 95 ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after"); 96 97 /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */ 98 uprobe_opts.retprobe = true; 99 uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; 100 uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe, 101 -1 /* any pid */, 102 "/proc/self/exe", 103 uprobe_offset, &uprobe_opts); 104 if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe")) 105 goto cleanup; 106 skel->links.handle_uretprobe = uretprobe_link; 107 108 /* verify auto-attach fails for old-style uprobe definition */ 109 uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname); 110 if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP, 111 "auto-attach should fail for old-style name")) 112 goto cleanup; 113 114 uprobe_opts.func_name = "trigger_func2"; 115 uprobe_opts.retprobe = false; 116 uprobe_opts.ref_ctr_offset = 0; 117 skel->links.handle_uprobe_byname = 118 bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname, 119 0 /* this pid */, 120 "/proc/self/exe", 121 0, &uprobe_opts); 122 if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname")) 123 goto cleanup; 124 125 /* verify auto-attach works */ 126 skel->links.handle_uretprobe_byname = 127 bpf_program__attach(skel->progs.handle_uretprobe_byname); 128 if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname")) 129 goto cleanup; 130 131 /* test attach by name for a library function, using the library 132 * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo(). 133 */ 134 uprobe_opts.func_name = "malloc"; 135 uprobe_opts.retprobe = false; 136 skel->links.handle_uprobe_byname2 = 137 bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2, 138 0 /* this pid */, 139 "libc.so.6", 140 0, &uprobe_opts); 141 if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2")) 142 goto cleanup; 143 144 uprobe_opts.func_name = "free"; 145 uprobe_opts.retprobe = true; 146 skel->links.handle_uretprobe_byname2 = 147 bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2, 148 -1 /* any pid */, 149 "libc.so.6", 150 0, &uprobe_opts); 151 if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2")) 152 goto cleanup; 153 154 /* trigger & validate kprobe && kretprobe */ 155 usleep(1); 156 157 /* trigger & validate shared library u[ret]probes attached by name */ 158 mem = malloc(1); 159 free(mem); 160 161 /* trigger & validate uprobe & uretprobe */ 162 trigger_func(); 163 164 /* trigger & validate uprobe attached by name */ 165 trigger_func2(); 166 167 ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res"); 168 ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res"); 169 ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res"); 170 ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res"); 171 ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res"); 172 ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res"); 173 ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res"); 174 ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res"); 175 ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res"); 176 ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res"); 177 178cleanup: 179 test_attach_probe__destroy(skel); 180 ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_cleanup"); 181}