feat: 实现并测试 newfstatat 系统调用 (#1153)

* feat: 实现并测试 newfstatat 系统调用

新增了 newfstatat 系统调用的实现，并添加了相应的测试应用。

Signed-off-by: longjin <longjin@DragonOS.org>

* feat(loongarch64/riscv64): 添加文件系统模块并实现GenericPosixStat结构

为loongarch64和riscv64架构添加filesystem模块，包含stat子模块，并实现GenericPosixStat结构用于处理文件状态信息。

Signed-off-by: longjin <longjin@DragonOS.org>

---------

Signed-off-by: longjin <longjin@DragonOS.org>

user/apps/test_newfstatat/.gitignore

@@ -0,0 +1 @@
+test_newfstatat

user/apps/test_newfstatat/Makefile

@@ -0,0 +1,20 @@
+ifeq ($(ARCH), x86_64)
+	CROSS_COMPILE=x86_64-linux-musl-
+else ifeq ($(ARCH), riscv64)
+	CROSS_COMPILE=riscv64-linux-musl-
+endif
+
+CC=$(CROSS_COMPILE)gcc
+
+.PHONY: all
+all: main.c
+	$(CC) -static -o test_newfstatat main.c
+
+.PHONY: install clean
+install: all
+	mv test_newfstatat $(DADK_CURRENT_BUILD_DIR)/test_newfstatat
+
+clean:
+	rm test_newfstatat *.o
+
+fmt:

user/apps/test_newfstatat/main.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/syscall.h>
+
+
+
+#define TEST_DIR "test_dir"
+#define TEST_FILE "test_file"
+
+void create_test_files() {
+    mkdir(TEST_DIR, 0755);
+    int fd = open(TEST_FILE, O_CREAT | O_RDWR, 0644);
+    if (fd >= 0) close(fd);
+}
+
+void cleanup_test_files() {
+    unlink(TEST_FILE);
+    rmdir(TEST_DIR);
+}
+
+void run_test(const char *name, int (*test_func)(), int expected) {
+    printf("Testing %s... ", name);
+    int result = test_func();
+    if (result == expected) {
+        printf("[PASS]\n");
+    } else {
+        printf("[FAILED] (expected %d, got %d)\n", expected, result);
+    }
+}
+
+int test_normal_file() {
+    struct stat st;
+    return syscall(__NR_newfstatat, AT_FDCWD, TEST_FILE, &st, 0);
+}
+
+int test_directory() {
+    struct stat st;
+    return syscall(__NR_newfstatat, AT_FDCWD, TEST_DIR, &st, 0);
+}
+
+int test_invalid_fd() {
+    struct stat st;
+    return syscall(__NR_newfstatat, -1, TEST_FILE, &st, 0);
+}
+
+int test_nonexistent_path() {
+    struct stat st;
+    return syscall(__NR_newfstatat, AT_FDCWD, "nonexistent_file", &st, 0);
+}
+
+int main() {
+    create_test_files();
+
+    run_test("normal file stat", test_normal_file, 0);
+    run_test("directory stat", test_directory, 0);
+    run_test("invalid file descriptor", test_invalid_fd, -1);
+    run_test("nonexistent path", test_nonexistent_path, -1);
+
+    cleanup_test_files();
+    return 0;
+}