bpf/prog_tests/attach_probe.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <test_progs.h>
0003 #include "test_attach_probe.skel.h"
0004
0005 /* this is how USDT semaphore is actually defined, except volatile modifier */
0006 volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes")));
0007
0008 /* uprobe attach point */
0009 static void trigger_func(void)
0010 {
0011     asm volatile ("");
0012 }
0013
0014 /* attach point for byname uprobe */
0015 static void trigger_func2(void)
0016 {
0017     asm volatile ("");
0018 }
0019
0020 /* attach point for byname sleepable uprobe */
0021 static void trigger_func3(void)
0022 {
0023     asm volatile ("");
0024 }
0025
0026 static char test_data[] = "test_data";
0027
0028 void test_attach_probe(void)
0029 {
0030     DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
0031     struct bpf_link *kprobe_link, *kretprobe_link;
0032     struct bpf_link *uprobe_link, *uretprobe_link;
0033     struct test_attach_probe* skel;
0034     ssize_t uprobe_offset, ref_ctr_offset;
0035     struct bpf_link *uprobe_err_link;
0036     bool legacy;
0037     char *mem;
0038
0039     /* Check if new-style kprobe/uprobe API is supported.
0040      * Kernels that support new FD-based kprobe and uprobe BPF attachment
0041      * through perf_event_open() syscall expose
0042      * /sys/bus/event_source/devices/kprobe/type and
0043      * /sys/bus/event_source/devices/uprobe/type files, respectively. They
0044      * contain magic numbers that are passed as "type" field of
0045      * perf_event_attr. Lack of such file in the system indicates legacy
0046      * kernel with old-style kprobe/uprobe attach interface through
0047      * creating per-probe event through tracefs. For such cases
0048      * ref_ctr_offset feature is not supported, so we don't test it.
0049      */
0050     legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0;
0051
0052     uprobe_offset = get_uprobe_offset(&trigger_func);
0053     if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset"))
0054         return;
0055
0056     ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
0057     if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
0058         return;
0059
0060     skel = test_attach_probe__open();
0061     if (!ASSERT_OK_PTR(skel, "skel_open"))
0062         return;
0063
0064     /* sleepable kprobe test case needs flags set before loading */
0065     if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable,
0066         BPF_F_SLEEPABLE), "kprobe_sleepable_flags"))
0067         goto cleanup;
0068
0069     if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load"))
0070         goto cleanup;
0071     if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
0072         goto cleanup;
0073
0074     /* manual-attach kprobe/kretprobe */
0075     kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
0076                          false /* retprobe */,
0077                          SYS_NANOSLEEP_KPROBE_NAME);
0078     if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
0079         goto cleanup;
0080     skel->links.handle_kprobe = kprobe_link;
0081
0082     kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe,
0083                             true /* retprobe */,
0084                             SYS_NANOSLEEP_KPROBE_NAME);
0085     if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe"))
0086         goto cleanup;
0087     skel->links.handle_kretprobe = kretprobe_link;
0088
0089     /* auto-attachable kprobe and kretprobe */
0090     skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto);
0091     ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto");
0092
0093     skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto);
0094     ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto");
0095
0096     if (!legacy)
0097         ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before");
0098
0099     uprobe_opts.retprobe = false;
0100     uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
0101     uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe,
0102                               0 /* self pid */,
0103                               "/proc/self/exe",
0104                               uprobe_offset,
0105                               &uprobe_opts);
0106     if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe"))
0107         goto cleanup;
0108     skel->links.handle_uprobe = uprobe_link;
0109
0110     if (!legacy)
0111         ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after");
0112
0113     /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */
0114     uprobe_opts.retprobe = true;
0115     uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
0116     uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe,
0117                              -1 /* any pid */,
0118                              "/proc/self/exe",
0119                              uprobe_offset, &uprobe_opts);
0120     if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe"))
0121         goto cleanup;
0122     skel->links.handle_uretprobe = uretprobe_link;
0123
0124     /* verify auto-attach fails for old-style uprobe definition */
0125     uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);
0126     if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,
0127                "auto-attach should fail for old-style name"))
0128         goto cleanup;
0129
0130     uprobe_opts.func_name = "trigger_func2";
0131     uprobe_opts.retprobe = false;
0132     uprobe_opts.ref_ctr_offset = 0;
0133     skel->links.handle_uprobe_byname =
0134             bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname,
0135                             0 /* this pid */,
0136                             "/proc/self/exe",
0137                             0, &uprobe_opts);
0138     if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname"))
0139         goto cleanup;
0140
0141     /* verify auto-attach works */
0142     skel->links.handle_uretprobe_byname =
0143             bpf_program__attach(skel->progs.handle_uretprobe_byname);
0144     if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname"))
0145         goto cleanup;
0146
0147     /* test attach by name for a library function, using the library
0148      * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo().
0149      */
0150     uprobe_opts.func_name = "malloc";
0151     uprobe_opts.retprobe = false;
0152     skel->links.handle_uprobe_byname2 =
0153             bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2,
0154                             0 /* this pid */,
0155                             "libc.so.6",
0156                             0, &uprobe_opts);
0157     if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2"))
0158         goto cleanup;
0159
0160     uprobe_opts.func_name = "free";
0161     uprobe_opts.retprobe = true;
0162     skel->links.handle_uretprobe_byname2 =
0163             bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2,
0164                             -1 /* any pid */,
0165                             "libc.so.6",
0166                             0, &uprobe_opts);
0167     if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2"))
0168         goto cleanup;
0169
0170     /* sleepable kprobes should not attach successfully */
0171     skel->links.handle_kprobe_sleepable = bpf_program__attach(skel->progs.handle_kprobe_sleepable);
0172     if (!ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable"))
0173         goto cleanup;
0174
0175     /* test sleepable uprobe and uretprobe variants */
0176     skel->links.handle_uprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uprobe_byname3_sleepable);
0177     if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3_sleepable, "attach_uprobe_byname3_sleepable"))
0178         goto cleanup;
0179
0180     skel->links.handle_uprobe_byname3 = bpf_program__attach(skel->progs.handle_uprobe_byname3);
0181     if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3, "attach_uprobe_byname3"))
0182         goto cleanup;
0183
0184     skel->links.handle_uretprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uretprobe_byname3_sleepable);
0185     if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3_sleepable, "attach_uretprobe_byname3_sleepable"))
0186         goto cleanup;
0187
0188     skel->links.handle_uretprobe_byname3 = bpf_program__attach(skel->progs.handle_uretprobe_byname3);
0189     if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3, "attach_uretprobe_byname3"))
0190         goto cleanup;
0191
0192     skel->bss->user_ptr = test_data;
0193
0194     /* trigger & validate kprobe && kretprobe */
0195     usleep(1);
0196
0197     /* trigger & validate shared library u[ret]probes attached by name */
0198     mem = malloc(1);
0199     free(mem);
0200
0201     /* trigger & validate uprobe & uretprobe */
0202     trigger_func();
0203
0204     /* trigger & validate uprobe attached by name */
0205     trigger_func2();
0206
0207     /* trigger & validate sleepable uprobe attached by name */
0208     trigger_func3();
0209
0210     ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
0211     ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res");
0212     ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
0213     ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res");
0214     ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");
0215     ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");
0216     ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");
0217     ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");
0218     ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");
0219     ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");
0220     ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
0221     ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
0222     ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
0223     ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
0224
0225 cleanup:
0226     test_attach_probe__destroy(skel);
0227     ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_cleanup");
0228 }