selftests/bpf: Add tests for symbol versioning for uprobe

This exercises the newly added dynsym symbol versioning logics.
Now we accept symbols in form of func, func@LIB_VERSION or
func@@LIB_VERSION.

The test rely on liburandom_read.so. For liburandom_read.so, we have:

    $ nm -D liburandom_read.so
                     w __cxa_finalize@GLIBC_2.17
                     w __gmon_start__
                     w _ITM_deregisterTMCloneTable
                     w _ITM_registerTMCloneTable
    0000000000000000 A LIBURANDOM_READ_1.0.0
    0000000000000000 A LIBURANDOM_READ_2.0.0
    000000000000081c T urandlib_api@@LIBURANDOM_READ_2.0.0
    0000000000000814 T urandlib_api@LIBURANDOM_READ_1.0.0
    0000000000000824 T urandlib_api_sameoffset@LIBURANDOM_READ_1.0.0
    0000000000000824 T urandlib_api_sameoffset@@LIBURANDOM_READ_2.0.0
    000000000000082c T urandlib_read_without_sema@@LIBURANDOM_READ_1.0.0
    00000000000007c4 T urandlib_read_with_sema@@LIBURANDOM_READ_1.0.0
    0000000000011018 D urandlib_read_with_sema_semaphore@@LIBURANDOM_READ_1.0.0

For `urandlib_api`, specifying `urandlib_api` will cause a conflict because
there are two symbols named urandlib_api and both are global bind.
For `urandlib_api_sameoffset`, there are also two symbols in the .so, but
both are at the same offset and essentially they refer to the same function
so no conflict.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230918024813.237475-4-hengqi.chen@gmail.com

1 files changed, 61 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_uprobe.c b/tools/testing/selftests/bpf/progs/test_uprobe.c
new file mode 100644
index 000000000000..896c88a4960d
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_uprobe.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Hengqi Chen */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+pid_t my_pid = 0;
+
+int test1_result = 0;
+int test2_result = 0;
+int test3_result = 0;
+int test4_result = 0;
+
+SEC("uprobe/./liburandom_read.so:urandlib_api_sameoffset")
+int BPF_UPROBE(test1)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (pid != my_pid)
+		return 0;
+
+	test1_result = 1;
+	return 0;
+}
+
+SEC("uprobe/./liburandom_read.so:urandlib_api_sameoffset@LIBURANDOM_READ_1.0.0")
+int BPF_UPROBE(test2)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (pid != my_pid)
+		return 0;
+
+	test2_result = 1;
+	return 0;
+}
+
+SEC("uretprobe/./liburandom_read.so:urandlib_api_sameoffset@@LIBURANDOM_READ_2.0.0")
+int BPF_URETPROBE(test3, int ret)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (pid != my_pid)
+		return 0;
+
+	test3_result = ret;
+	return 0;
+}
+
+SEC("uprobe")
+int BPF_UPROBE(test4)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (pid != my_pid)
+		return 0;
+
+	test4_result = 1;
+	return 0;
+}