ospp project (feature) add namespace overlayfs cgroup (#949)

## 开发进展： ## namespace - pid_namespace 基本实现，基于pid_struct等数据结构实现隔离 - mnt_namespace 基本实现，挂载点的隔离通过不同的挂载树来实现 - usernamespace 作为支持性的namespace，目前受限实现全局静态 ## overlayfs - 实现若干个文件系统的叠加，在mount中传入多个路径作为多个fs的mount路径以及最后merge层的fs路径 - copy-up机制的，除最上层外其他层为只读层，满足写时拷贝，需要修改的时候copy到上层修改 - whiteout特殊文件，用于标记在下层需要被删除的文件用来掩盖需要删除的文件 ## cgroups - 目前cgroups还处于框架阶段，之后具体实现具体的内存、CPU等子系统
2025-06-18 12:16:31 +00:00 · 2024-10-31 00:50:34 +08:00
parent 84c528f53d
commit f5b2038871
43 changed files with 2279 additions and 56 deletions
--- a/user/apps/test_overlayfs/main.c
+++ b/user/apps/test_overlayfs/main.c
@ -0,0 +1,92 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+
+// #define LOWERDIR "/tmp/overlayfs/lower"
+// #define UPPERDIR "/tmp/overlayfs/upper"
+// #define WORKDIR "/tmp/overlayfs/work"
+// #define MERGEDDIR "/tmp/overlayfs/merged"
+
+// void create_directories()
+// {
+//     mkdir(LOWERDIR, 0755);
+//     mkdir(UPPERDIR, 0755);
+//     mkdir(WORKDIR, 0755);
+//     mkdir(MERGEDDIR, 0755);
+// }
+#define TMPDIR "/tmp"
+#define OVERLAYFSDIR "/tmp/overlayfs"
+#define LOWERDIR "/tmp/overlayfs/lower"
+#define UPPERDIR "/tmp/overlayfs/upper"
+#define WORKDIR "/tmp/overlayfs/work"
+#define MERGEDDIR "/tmp/overlayfs/merged"
+
+void create_directories()
+{
+    mkdir(TMPDIR, 0755);
+    mkdir(OVERLAYFSDIR, 0755);
+    mkdir(LOWERDIR, 0755);
+    mkdir(UPPERDIR, 0755);
+    mkdir(WORKDIR, 0755);
+    mkdir(MERGEDDIR, 0755);
+    printf("step1 : success\n");
+}
+
+void create_lower_file()
+{
+    char filepath[256];
+    snprintf(filepath, sizeof(filepath), "%s/lowerfile.txt", LOWERDIR);
+
+    int fd = open(filepath, O_CREAT | O_WRONLY, 0644);
+    if (fd < 0)
+    {
+        perror("Failed to create file in lowerdir");
+        exit(EXIT_FAILURE);
+    }
+    write(fd, "This is a lower layer file.\n", 28);
+    close(fd);
+    printf("step2 : success\n");
+}
+
+void mount_overlayfs()
+{
+    char options[1024];
+    snprintf(options, sizeof(options),
+             "lowerdir=%s,upperdir=%s,workdir=%s",
+             LOWERDIR, UPPERDIR, WORKDIR);
+
+    if (mount("overlay", MERGEDDIR, "overlay", 0, options) != 0)
+    {
+        perror("Mount failed");
+        exit(EXIT_FAILURE);
+    }
+    printf("OverlayFS mounted successfully.\n");
+    printf("step3 : success\n");
+}
+
+void create_directory_in_merged()
+{
+    char dirpath[256];
+    snprintf(dirpath, sizeof(dirpath), "%s/newdir", UPPERDIR);
+
+    if (mkdir(dirpath, 0755) != 0)
+    {
+        perror("Failed to create directory in merged dir");
+        exit(EXIT_FAILURE);
+    }
+    printf("Directory created in merged: %s\n", dirpath);
+    printf("step4 : success\n");
+}
+
+int main()
+{
+    create_directories();
+    mount_overlayfs();
+    create_directory_in_merged();
+    return 0;
+}