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.
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>
---
tools/testing/selftests/bpf/Makefile | 5 +-
.../testing/selftests/bpf/liburandom_read.map | 15 +++
.../testing/selftests/bpf/prog_tests/uprobe.c | 95 +++++++++++++++++++
.../testing/selftests/bpf/progs/test_uprobe.c | 61 ++++++++++++
tools/testing/selftests/bpf/urandom_read.c | 9 ++
.../testing/selftests/bpf/urandom_read_lib1.c | 41 ++++++++
6 files changed, 224 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/bpf/liburandom_read.map
create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe.c
create mode 100644 tools/testing/selftests/bpf/progs/test_uprobe.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index caede9b574cb..47365161b6fc 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -196,11 +196,12 @@ endif
# Filter out -static for liburandom_read.so and its dependent targets so that static builds
# do not fail. Static builds leave urandom_read relying on system-wide shared libraries.
-$(OUTPUT)/liburandom_read.so: urandom_read_lib1.c urandom_read_lib2.c
+$(OUTPUT)/liburandom_read.so: urandom_read_lib1.c urandom_read_lib2.c liburandom_read.map
$(call msg,LIB,,$@)
$(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) \
- $^ $(filter-out -static,$(LDLIBS)) \
+ $(filter %.c,$^) $(filter-out -static,$(LDLIBS)) \
-fuse-ld=$(LLD) -Wl,-znoseparate-code -Wl,--build-id=sha1 \
+ -Wl,--version-script=liburandom_read.map \
-fPIC -shared -o $@
$(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c $(OUTPUT)/liburandom_read.so
diff --git a/tools/testing/selftests/bpf/liburandom_read.map b/tools/testing/selftests/bpf/liburandom_read.map
new file mode 100644
index 000000000000..38a97a419a04
--- /dev/null
+++ b/tools/testing/selftests/bpf/liburandom_read.map
@@ -0,0 +1,15 @@
+LIBURANDOM_READ_1.0.0 {
+ global:
+ urandlib_api;
+ urandlib_api_sameoffset;
+ urandlib_read_without_sema;
+ urandlib_read_with_sema;
+ urandlib_read_with_sema_semaphore;
+ local:
+ *;
+};
+
+LIBURANDOM_READ_2.0.0 {
+ global:
+ urandlib_api;
+} LIBURANDOM_READ_1.0.0;
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe.c b/tools/testing/selftests/bpf/prog_tests/uprobe.c
new file mode 100644
index 000000000000..cf3e0e7a64fa
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Hengqi Chen */
+
+#include <test_progs.h>
+#include "test_uprobe.skel.h"
+
+static FILE *urand_spawn(int *pid)
+{
+ FILE *f;
+
+ /* urandom_read's stdout is wired into f */
+ f = popen("./urandom_read 1 report-pid", "r");
+ if (!f)
+ return NULL;
+
+ if (fscanf(f, "%d", pid) != 1) {
+ pclose(f);
+ errno = EINVAL;
+ return NULL;
+ }
+
+ return f;
+}
+
+static int urand_trigger(FILE **urand_pipe)
+{
+ int exit_code;
+
+ /* pclose() waits for child process to exit and returns their exit code */
+ exit_code = pclose(*urand_pipe);
+ *urand_pipe = NULL;
+
+ return exit_code;
+}
+
+void test_uprobe(void)
+{
+ LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
+ struct test_uprobe *skel;
+ FILE *urand_pipe = NULL;
+ int urand_pid = 0, err;
+
+ skel = test_uprobe__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ urand_pipe = urand_spawn(&urand_pid);
+ if (!ASSERT_OK_PTR(urand_pipe, "urand_spawn"))
+ goto cleanup;
+
+ skel->bss->my_pid = urand_pid;
+
+ /* Manual attach uprobe to urandlib_api
+ * There are two `urandlib_api` symbols in .dynsym section:
+ * - urandlib_api@LIBURANDOM_READ_1.0.0
+ * - urandlib_api@@LIBURANDOM_READ_2.0.0
+ * Both are global bind and would cause a conflict if user
+ * specify the symbol name without a version suffix
+ */
+ uprobe_opts.func_name = "urandlib_api";
+ skel->links.test4 = bpf_program__attach_uprobe_opts(skel->progs.test4,
+ urand_pid,
+ "./liburandom_read.so",
+ 0 /* offset */,
+ &uprobe_opts);
+ if (!ASSERT_ERR_PTR(skel->links.test4, "urandlib_api_attach_conflict"))
+ goto cleanup;
+
+ uprobe_opts.func_name = "urandlib_api@LIBURANDOM_READ_1.0.0";
+ skel->links.test4 = bpf_program__attach_uprobe_opts(skel->progs.test4,
+ urand_pid,
+ "./liburandom_read.so",
+ 0 /* offset */,
+ &uprobe_opts);
+ if (!ASSERT_OK_PTR(skel->links.test4, "urandlib_api_attach_ok"))
+ goto cleanup;
+
+ /* Auto attach 3 u[ret]probes to urandlib_api_sameoffset */
+ err = test_uprobe__attach(skel);
+ if (!ASSERT_OK(err, "skel_attach"))
+ goto cleanup;
+
+ /* trigger urandom_read */
+ ASSERT_OK(urand_trigger(&urand_pipe), "urand_exit_code");
+
+ ASSERT_EQ(skel->bss->test1_result, 1, "urandlib_api_sameoffset");
+ ASSERT_EQ(skel->bss->test2_result, 1, "urandlib_api_sameoffset@v1");
+ ASSERT_EQ(skel->bss->test3_result, 3, "urandlib_api_sameoffset@@v2");
+ ASSERT_EQ(skel->bss->test4_result, 1, "urandlib_api");
+
+cleanup:
+ if (urand_pipe)
+ pclose(urand_pipe);
+ test_uprobe__destroy(skel);
+}
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;
+}
diff --git a/tools/testing/selftests/bpf/urandom_read.c b/tools/testing/selftests/bpf/urandom_read.c
index e92644d0fa75..b28e910a8fbb 100644
--- a/tools/testing/selftests/bpf/urandom_read.c
+++ b/tools/testing/selftests/bpf/urandom_read.c
@@ -21,6 +21,11 @@ void urand_read_without_sema(int iter_num, int iter_cnt, int read_sz);
void urandlib_read_with_sema(int iter_num, int iter_cnt, int read_sz);
void urandlib_read_without_sema(int iter_num, int iter_cnt, int read_sz);
+int urandlib_api(void);
+__asm__(".symver urandlib_api_old,urandlib_api@LIBURANDOM_READ_1.0.0");
+int urandlib_api_old(void);
+int urandlib_api_sameoffset(void);
+
unsigned short urand_read_with_sema_semaphore SEC(".probes");
static __attribute__((noinline))
@@ -83,6 +88,10 @@ int main(int argc, char *argv[])
urandom_read(fd, count);
+ urandlib_api();
+ urandlib_api_old();
+ urandlib_api_sameoffset();
+
close(fd);
return 0;
}
diff --git a/tools/testing/selftests/bpf/urandom_read_lib1.c b/tools/testing/selftests/bpf/urandom_read_lib1.c
index 86186e24b740..403b0735e223 100644
--- a/tools/testing/selftests/bpf/urandom_read_lib1.c
+++ b/tools/testing/selftests/bpf/urandom_read_lib1.c
@@ -11,3 +11,44 @@ void urandlib_read_with_sema(int iter_num, int iter_cnt, int read_sz)
{
STAP_PROBE3(urandlib, read_with_sema, iter_num, iter_cnt, read_sz);
}
+
+/* Symbol versioning is different between static and shared library.
+ * Properly versioned symbols are needed for shared library, but
+ * only the symbol of the new version is needed for static library.
+ * Starting with GNU C 10, use symver attribute instead of .symver assembler
+ * directive, which works better with GCC LTO builds.
+ */
+#if defined(__GNUC__) && __GNUC__ >= 10
+
+#define DEFAULT_VERSION(internal_name, api_name, version) \
+ __attribute__((symver(#api_name "@@" #version)))
+#define COMPAT_VERSION(internal_name, api_name, version) \
+ __attribute__((symver(#api_name "@" #version)))
+
+#else
+
+#define COMPAT_VERSION(internal_name, api_name, version) \
+ asm(".symver " #internal_name "," #api_name "@" #version);
+#define DEFAULT_VERSION(internal_name, api_name, version) \
+ asm(".symver " #internal_name "," #api_name "@@" #version);
+
+#endif
+
+COMPAT_VERSION(urandlib_api_v1, urandlib_api, LIBURANDOM_READ_1.0.0)
+int urandlib_api_v1(void)
+{
+ return 1;
+}
+
+DEFAULT_VERSION(urandlib_api_v2, urandlib_api, LIBURANDOM_READ_2.0.0)
+int urandlib_api_v2(void)
+{
+ return 2;
+}
+
+COMPAT_VERSION(urandlib_api_sameoffset, urandlib_api_sameoffset, LIBURANDOM_READ_1.0.0)
+DEFAULT_VERSION(urandlib_api_sameoffset, urandlib_api_sameoffset, LIBURANDOM_READ_2.0.0)
+int urandlib_api_sameoffset(void)
+{
+ return 3;
+}
--
2.34.1
