selftests/bpf: Factor out get_xlated_program() helper

Both test_verifier and test_progs use get_xlated_program(), so moving
the helper into testing_helpers.h to reuse it.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20240105104819.3916743-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c

@@ -626,50 +626,6 @@ err:
 	return false;
 }
 
-/* Request BPF program instructions after all rewrites are applied,
- * e.g. verifier.c:convert_ctx_access() is done.
- */
-static int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt)
-{
-	struct bpf_prog_info info = {};
-	__u32 info_len = sizeof(info);
-	__u32 xlated_prog_len;
-	__u32 buf_element_size = sizeof(struct bpf_insn);
-
-	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
-		perror("bpf_prog_get_info_by_fd failed");
-		return -1;
-	}
-
-	xlated_prog_len = info.xlated_prog_len;
-	if (xlated_prog_len % buf_element_size) {
-		printf("Program length %d is not multiple of %d\n",
-		       xlated_prog_len, buf_element_size);
-		return -1;
-	}
-
-	*cnt = xlated_prog_len / buf_element_size;
-	*buf = calloc(*cnt, buf_element_size);
-	if (!buf) {
-		perror("can't allocate xlated program buffer");
-		return -ENOMEM;
-	}
-
-	bzero(&info, sizeof(info));
-	info.xlated_prog_len = xlated_prog_len;
-	info.xlated_prog_insns = (__u64)(unsigned long)*buf;
-	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
-		perror("second bpf_prog_get_info_by_fd failed");
-		goto out_free_buf;
-	}
-
-	return 0;
-
-out_free_buf:
-	free(*buf);
-	return -1;
-}
-
 static void print_insn(void *private_data, const char *fmt, ...)
 {
 	va_list args;

tools/testing/selftests/bpf/test_verifier.c

@@ -1341,48 +1341,6 @@ static bool cmp_str_seq(const char *log, const char *exp)
 	return true;
 }
 
-static struct bpf_insn *get_xlated_program(int fd_prog, int *cnt)
-{
-	__u32 buf_element_size = sizeof(struct bpf_insn);
-	struct bpf_prog_info info = {};
-	__u32 info_len = sizeof(info);
-	__u32 xlated_prog_len;
-	struct bpf_insn *buf;
-
-	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
-		perror("bpf_prog_get_info_by_fd failed");
-		return NULL;
-	}
-
-	xlated_prog_len = info.xlated_prog_len;
-	if (xlated_prog_len % buf_element_size) {
-		printf("Program length %d is not multiple of %d\n",
-		       xlated_prog_len, buf_element_size);
-		return NULL;
-	}
-
-	*cnt = xlated_prog_len / buf_element_size;
-	buf = calloc(*cnt, buf_element_size);
-	if (!buf) {
-		perror("can't allocate xlated program buffer");
-		return NULL;
-	}
-
-	bzero(&info, sizeof(info));
-	info.xlated_prog_len = xlated_prog_len;
-	info.xlated_prog_insns = (__u64)(unsigned long)buf;
-	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
-		perror("second bpf_prog_get_info_by_fd failed");
-		goto out_free_buf;
-	}
-
-	return buf;
-
-out_free_buf:
-	free(buf);
-	return NULL;
-}
-
 static bool is_null_insn(struct bpf_insn *insn)
 {
 	struct bpf_insn null_insn = {};
@@ -1505,7 +1463,7 @@ static void print_insn(struct bpf_insn *buf, int cnt)
 static bool check_xlated_program(struct bpf_test *test, int fd_prog)
 {
 	struct bpf_insn *buf;
-	int cnt;
+	unsigned int cnt;
 	bool result = true;
 	bool check_expected = !is_null_insn(test->expected_insns);
 	bool check_unexpected = !is_null_insn(test->unexpected_insns);
@@ -1513,8 +1471,7 @@ static bool check_xlated_program(struct bpf_test *test, int fd_prog)
 	if (!check_expected && !check_unexpected)
 		goto out;
 
-	buf = get_xlated_program(fd_prog, &cnt);
+	if (get_xlated_program(fd_prog, &buf, &cnt)) {
-	if (!buf) {
 		printf("FAIL: can't get xlated program\n");
 		result = false;
 		goto out;

tools/testing/selftests/bpf/testing_helpers.c

@@ -387,3 +387,45 @@ int kern_sync_rcu(void)
 {
 	return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
 }
+
+int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt)
+{
+	__u32 buf_element_size = sizeof(struct bpf_insn);
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
+	__u32 xlated_prog_len;
+
+	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
+		perror("bpf_prog_get_info_by_fd failed");
+		return -1;
+	}
+
+	xlated_prog_len = info.xlated_prog_len;
+	if (xlated_prog_len % buf_element_size) {
+		printf("Program length %u is not multiple of %u\n",
+		       xlated_prog_len, buf_element_size);
+		return -1;
+	}
+
+	*cnt = xlated_prog_len / buf_element_size;
+	*buf = calloc(*cnt, buf_element_size);
+	if (!buf) {
+		perror("can't allocate xlated program buffer");
+		return -ENOMEM;
+	}
+
+	bzero(&info, sizeof(info));
+	info.xlated_prog_len = xlated_prog_len;
+	info.xlated_prog_insns = (__u64)(unsigned long)*buf;
+	if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
+		perror("second bpf_prog_get_info_by_fd failed");
+		goto out_free_buf;
+	}
+
+	return 0;
+
+out_free_buf:
+	free(*buf);
+	*buf = NULL;
+	return -1;
+}

tools/testing/selftests/bpf/testing_helpers.h

@@ -46,4 +46,10 @@ static inline __u64 get_time_ns(void)
 	return (u64)t.tv_sec * 1000000000 + t.tv_nsec;
 }
 
+struct bpf_insn;
+/* Request BPF program instructions after all rewrites are applied,
+ * e.g. verifier.c:convert_ctx_access() is done.
+ */
+int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt);
+
 #endif /* __TESTING_HELPERS_H */