// SPDX-License-Identifier: GPL-2.0 #include #include "test_attach_probe.skel.h" /* this is how USDT semaphore is actually defined, except volatile modifier */ volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes"))); /* uprobe attach point */ static void trigger_func(void) { asm volatile (""); } /* attach point for byname uprobe */ static void trigger_func2(void) { asm volatile (""); } /* attach point for byname sleepable uprobe */ static void trigger_func3(void) { asm volatile (""); } static char test_data[] = "test_data"; void test_attach_probe(void) { DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); struct bpf_link *kprobe_link, *kretprobe_link; struct bpf_link *uprobe_link, *uretprobe_link; struct test_attach_probe* skel; ssize_t uprobe_offset, ref_ctr_offset; struct bpf_link *uprobe_err_link; bool legacy; char *mem; /* Check if new-style kprobe/uprobe API is supported. * Kernels that support new FD-based kprobe and uprobe BPF attachment * through perf_event_open() syscall expose * /sys/bus/event_source/devices/kprobe/type and * /sys/bus/event_source/devices/uprobe/type files, respectively. They * contain magic numbers that are passed as "type" field of * perf_event_attr. Lack of such file in the system indicates legacy * kernel with old-style kprobe/uprobe attach interface through * creating per-probe event through tracefs. For such cases * ref_ctr_offset feature is not supported, so we don't test it. */ legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0; uprobe_offset = get_uprobe_offset(&trigger_func); if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset")) return; ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr); if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset")) return; skel = test_attach_probe__open(); if (!ASSERT_OK_PTR(skel, "skel_open")) return; /* sleepable kprobe test case needs flags set before loading */ if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable, BPF_F_SLEEPABLE), "kprobe_sleepable_flags")) goto cleanup; if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load")) goto cleanup; if (!ASSERT_OK_PTR(skel->bss, "check_bss")) goto cleanup; /* manual-attach kprobe/kretprobe */ kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe, false /* retprobe */, SYS_NANOSLEEP_KPROBE_NAME); if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe")) goto cleanup; skel->links.handle_kprobe = kprobe_link; kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe, true /* retprobe */, SYS_NANOSLEEP_KPROBE_NAME); if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe")) goto cleanup; skel->links.handle_kretprobe = kretprobe_link; /* auto-attachable kprobe and kretprobe */ skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto); ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto"); skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto); ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto"); if (!legacy) ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before"); uprobe_opts.retprobe = false; uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe, 0 /* self pid */, "/proc/self/exe", uprobe_offset, &uprobe_opts); if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe")) goto cleanup; skel->links.handle_uprobe = uprobe_link; if (!legacy) ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after"); /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */ uprobe_opts.retprobe = true; uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset; uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe, -1 /* any pid */, "/proc/self/exe", uprobe_offset, &uprobe_opts); if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe")) goto cleanup; skel->links.handle_uretprobe = uretprobe_link; /* verify auto-attach fails for old-style uprobe definition */ uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname); if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP, "auto-attach should fail for old-style name")) goto cleanup; uprobe_opts.func_name = "trigger_func2"; uprobe_opts.retprobe = false; uprobe_opts.ref_ctr_offset = 0; skel->links.handle_uprobe_byname = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname, 0 /* this pid */, "/proc/self/exe", 0, &uprobe_opts); if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname")) goto cleanup; /* verify auto-attach works */ skel->links.handle_uretprobe_byname = bpf_program__attach(skel->progs.handle_uretprobe_byname); if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname")) goto cleanup; /* test attach by name for a library function, using the library * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo(). */ uprobe_opts.func_name = "malloc"; uprobe_opts.retprobe = false; skel->links.handle_uprobe_byname2 = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2, 0 /* this pid */, "libc.so.6", 0, &uprobe_opts); if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2")) goto cleanup; uprobe_opts.func_name = "free"; uprobe_opts.retprobe = true; skel->links.handle_uretprobe_byname2 = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2, -1 /* any pid */, "libc.so.6", 0, &uprobe_opts); if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2")) goto cleanup; /* sleepable kprobes should not attach successfully */ skel->links.handle_kprobe_sleepable = bpf_program__attach(skel->progs.handle_kprobe_sleepable); if (!ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable")) goto cleanup; /* test sleepable uprobe and uretprobe variants */ skel->links.handle_uprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uprobe_byname3_sleepable); if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3_sleepable, "attach_uprobe_byname3_sleepable")) goto cleanup; skel->links.handle_uprobe_byname3 = bpf_program__attach(skel->progs.handle_uprobe_byname3); if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3, "attach_uprobe_byname3")) goto cleanup; skel->links.handle_uretprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uretprobe_byname3_sleepable); if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3_sleepable, "attach_uretprobe_byname3_sleepable")) goto cleanup; skel->links.handle_uretprobe_byname3 = bpf_program__attach(skel->progs.handle_uretprobe_byname3); if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3, "attach_uretprobe_byname3")) goto cleanup; skel->bss->user_ptr = test_data; /* trigger & validate kprobe && kretprobe */ usleep(1); /* trigger & validate shared library u[ret]probes attached by name */ mem = malloc(1); free(mem); /* trigger & validate uprobe & uretprobe */ trigger_func(); /* trigger & validate uprobe attached by name */ trigger_func2(); /* trigger & validate sleepable uprobe attached by name */ trigger_func3(); ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res"); ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res"); ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res"); ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res"); ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res"); ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res"); ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res"); ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res"); ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res"); ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res"); ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res"); ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res"); ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res"); ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res"); cleanup: test_attach_probe__destroy(skel); ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_cleanup"); }