From ba7499bc9d52f7ea93301a48c05caa370c68b213 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Wed, 30 Mar 2022 16:26:39 +0100 Subject: [PATCH] selftests/bpf: Add tests for u[ret]probe attach by name add tests that verify attaching by name for 1. local functions in a program 2. library functions in a shared object ...succeed for uprobe and uretprobes using new "func_name" option for bpf_program__attach_uprobe_opts(). Also verify auto-attach works where uprobe, path to binary and function name are specified, but fails with -EOPNOTSUPP with a SEC name that does not specify binary path/function. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1648654000-21758-5-git-send-email-alan.maguire@oracle.com --- .../selftests/bpf/prog_tests/attach_probe.c | 85 +++++++++++++++---- .../selftests/bpf/progs/test_attach_probe.c | 41 ++++++++- 2 files changed, 109 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c index d48f6e533e1e..c0c6d410751d 100644 --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c @@ -11,15 +11,22 @@ static void trigger_func(void) asm volatile (""); } +/* attach point for byname uprobe */ +static void trigger_func2(void) +{ + asm volatile (""); +} + void test_attach_probe(void) { DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); - int duration = 0; 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 @@ -43,9 +50,9 @@ void test_attach_probe(void) return; skel = test_attach_probe__open_and_load(); - if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + if (!ASSERT_OK_PTR(skel, "skel_open")) return; - if (CHECK(!skel->bss, "check_bss", ".bss wasn't mmap()-ed\n")) + if (!ASSERT_OK_PTR(skel->bss, "check_bss")) goto cleanup; kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe, @@ -90,25 +97,73 @@ void test_attach_probe(void) goto cleanup; skel->links.handle_uretprobe = uretprobe_link; - /* trigger & validate kprobe && kretprobe */ - usleep(1); + /* 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; - if (CHECK(skel->bss->kprobe_res != 1, "check_kprobe_res", - "wrong kprobe res: %d\n", skel->bss->kprobe_res)) + /* 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; - if (CHECK(skel->bss->kretprobe_res != 2, "check_kretprobe_res", - "wrong kretprobe res: %d\n", skel->bss->kretprobe_res)) + + 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; + /* 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(); - if (CHECK(skel->bss->uprobe_res != 3, "check_uprobe_res", - "wrong uprobe res: %d\n", skel->bss->uprobe_res)) - goto cleanup; - if (CHECK(skel->bss->uretprobe_res != 4, "check_uretprobe_res", - "wrong uretprobe res: %d\n", skel->bss->uretprobe_res)) - goto cleanup; + /* trigger & validate uprobe attached by name */ + trigger_func2(); + + ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res"); + ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_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"); cleanup: test_attach_probe__destroy(skel); diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c index 8056a4c6d918..af994d16bb10 100644 --- a/tools/testing/selftests/bpf/progs/test_attach_probe.c +++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c @@ -10,6 +10,10 @@ int kprobe_res = 0; int kretprobe_res = 0; int uprobe_res = 0; int uretprobe_res = 0; +int uprobe_byname_res = 0; +int uretprobe_byname_res = 0; +int uprobe_byname2_res = 0; +int uretprobe_byname2_res = 0; SEC("kprobe/sys_nanosleep") int handle_kprobe(struct pt_regs *ctx) @@ -25,18 +29,51 @@ int BPF_KRETPROBE(handle_kretprobe) return 0; } -SEC("uprobe/trigger_func") +SEC("uprobe") int handle_uprobe(struct pt_regs *ctx) { uprobe_res = 3; return 0; } -SEC("uretprobe/trigger_func") +SEC("uretprobe") int handle_uretprobe(struct pt_regs *ctx) { uretprobe_res = 4; return 0; } +SEC("uprobe") +int handle_uprobe_byname(struct pt_regs *ctx) +{ + uprobe_byname_res = 5; + return 0; +} + +/* use auto-attach format for section definition. */ +SEC("uretprobe//proc/self/exe:trigger_func2") +int handle_uretprobe_byname(struct pt_regs *ctx) +{ + uretprobe_byname_res = 6; + return 0; +} + +SEC("uprobe") +int handle_uprobe_byname2(struct pt_regs *ctx) +{ + unsigned int size = PT_REGS_PARM1(ctx); + + /* verify malloc size */ + if (size == 1) + uprobe_byname2_res = 7; + return 0; +} + +SEC("uretprobe") +int handle_uretprobe_byname2(struct pt_regs *ctx) +{ + uretprobe_byname2_res = 8; + return 0; +} + char _license[] SEC("license") = "GPL"; -- 2.34.1