mirror of
https://github.com/DragonOS-Community/DragonOS.git
synced 2025-06-09 02:46:47 +00:00
556 lines
16 KiB
C
556 lines
16 KiB
C
#include "VFS.h"
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#include "mount.h"
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#include <common/kprint.h>
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#include <common/dirent.h>
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#include <common/string.h>
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#include <common/errno.h>
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#include <mm/mm.h>
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#include <mm/slab.h>
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#include <process/ptrace.h>
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#include <process/process.h>
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// todo: devfs完善后，删除这个
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extern struct vfs_file_operations_t ps2_keyboard_fops;
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// 为filesystem_type_t结构体实例化一个链表头
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static struct vfs_filesystem_type_t vfs_fs = {"filesystem", 0};
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struct vfs_superblock_t *vfs_root_sb = NULL;
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struct vfs_dir_entry_t *vfs_alloc_dentry(const int name_size);
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/**
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* @brief 挂载文件系统
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*
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* @param path 要挂载到的路径
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* @param name 文件系统名
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* @param blk 块设备结构体
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* @return struct vfs_superblock_t* 挂载后，文件系统的超级块
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*/
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struct vfs_superblock_t *vfs_mount_fs(const char *path, char *name, struct block_device *blk)
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{
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// todo: 选择挂载点
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// 判断挂载点是否存在
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struct vfs_dir_entry_t *target_dentry = NULL;
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// 由于目前还没有rootfs，因此挂载根目录时，不需要path walk
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if (strcmp(path, "/") != 0)
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{
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target_dentry = vfs_path_walk(path, 0);
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if (target_dentry == NULL)
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return NULL;
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}
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struct vfs_filesystem_type_t *p = NULL;
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for (p = &vfs_fs; p; p = p->next)
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{
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if (!strcmp(p->name, name)) // 存在符合的文件系统
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{
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struct vfs_superblock_t *sb = p->read_superblock(blk);
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if (strcmp(path, "/") == 0) // 如果挂载到的是'/'挂载点，则让其成为最顶层的文件系统
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vfs_root_sb = sb;
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else
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{
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kdebug("to mount %s", name);
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// 调用mount机制，挂载文件系统
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struct vfs_dir_entry_t *new_dentry = sb->root;
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// 注意，umount的时候需要释放这些内存
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new_dentry->name = kzalloc(target_dentry->name_length + 1, 0);
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new_dentry->name_length = target_dentry->name_length;
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do_mount(target_dentry, new_dentry);
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}
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return sb;
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}
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}
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kdebug("unsupported fs: %s", name);
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return NULL;
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}
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/**
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* @brief 在VFS中注册文件系统
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*
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* @param fs 文件系统类型结构体
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* @return uint64_t
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*/
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uint64_t vfs_register_filesystem(struct vfs_filesystem_type_t *fs)
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{
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struct vfs_filesystem_type_t *p = NULL;
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for (p = &vfs_fs; p; p = p->next)
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{
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if (!strcmp(p->name, fs->name)) // 已经注册相同名称的文件系统
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return VFS_E_FS_EXISTED;
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}
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fs->next = vfs_fs.next;
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vfs_fs.next = fs;
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return VFS_SUCCESS;
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}
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uint64_t vfs_unregister_filesystem(struct vfs_filesystem_type_t *fs)
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{
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struct vfs_filesystem_type_t *p = &vfs_fs;
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while (p->next)
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{
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if (p->next == fs)
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{
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p->next = p->next->next;
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fs->next = NULL;
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return VFS_SUCCESS;
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}
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else
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p = p->next;
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}
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return VFS_E_FS_NOT_EXIST;
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}
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/**
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* @brief 在dentry的sub_dir_list中搜索指定名称的dentry
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*
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* @param dentry 目录项结构体dentry
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* @param name 待搜索的dentry名称
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* @return struct vfs_dir_entry_t* 目标dentry （无结果则返回NULL）
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*/
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static struct vfs_dir_entry_t *vfs_search_dentry_list(struct vfs_dir_entry_t *dentry, const char *name)
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{
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if (list_empty(&dentry->subdirs_list))
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return NULL;
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struct List *ptr = &dentry->subdirs_list;
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struct vfs_dir_entry_t *d_ptr = NULL;
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do
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{
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ptr = list_next(ptr);
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d_ptr = container_of(ptr, struct vfs_dir_entry_t, child_node_list);
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if (strcmp(name, d_ptr->name) == 0)
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return d_ptr;
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} while (list_next(ptr) != (&dentry->subdirs_list));
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return NULL;
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}
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/**
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* @brief 按照路径查找文件
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*
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* @param path 路径
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* @param flags 1：返回父目录项， 0：返回结果目录项
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* @return struct vfs_dir_entry_t* 目录项
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*/
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struct vfs_dir_entry_t *vfs_path_walk(const char *path, uint64_t flags)
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{
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struct vfs_dir_entry_t *parent = vfs_root_sb->root;
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// 去除路径前的斜杠
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while (*path == '/')
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++path;
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if ((!*path) || (*path == '\0'))
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return parent;
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struct vfs_dir_entry_t *dentry = NULL;
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// kdebug("path before walk:%s", path);
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while (true)
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{
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// 提取出下一级待搜索的目录名或文件名，并保存在dEntry_name中
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char *tmp_path = path;
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while ((*path && *path != '\0') && (*path != '/'))
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++path;
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int tmp_path_len = path - tmp_path;
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// 搜索是否有dentry缓存
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{
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char bk = *(tmp_path + tmp_path_len);
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*(tmp_path + tmp_path_len) = '\0';
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// kdebug("to search:%s", tmp_path);
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dentry = vfs_search_dentry_list(parent, tmp_path);
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// kdebug("search done, dentry=%#018lx", dentry);
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*(tmp_path + tmp_path_len) = bk;
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}
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// 如果没有找到dentry缓存，则申请新的dentry
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if (dentry == NULL)
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{
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dentry = vfs_alloc_dentry(tmp_path_len+1);
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memcpy(dentry->name, (void *)tmp_path, tmp_path_len);
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dentry->name[tmp_path_len] = '\0';
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// kdebug("tmp_path_len=%d, dentry->name= %s", tmp_path_len, dentry->name);
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dentry->name_length = tmp_path_len;
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if (parent->dir_inode->inode_ops->lookup(parent->dir_inode, dentry) == NULL)
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{
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// 搜索失败
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// kerror("cannot find the file/dir : %s", dentry->name);
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kfree(dentry->name);
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kfree(dentry);
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return NULL;
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}
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// 找到子目录项
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dentry->parent = parent;
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list_add(&parent->subdirs_list, &dentry->child_node_list);
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}
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while (*path == '/')
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++path;
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if ((!*path) || (*path == '\0')) // 已经到达末尾
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{
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if (flags & 1) // 返回父目录
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{
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return parent;
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}
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return dentry;
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}
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parent = dentry;
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}
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}
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/**
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* @brief 填充dentry
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*
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* @return dirent的总大小
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*/
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int vfs_fill_dirent(void *buf, ino_t d_ino, char *name, int namelen, unsigned char type, off_t offset)
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{
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struct dirent *dent = (struct dirent *)buf;
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// 如果尝试访问内核空间，则返回错误
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if (!(verify_area((uint64_t)buf, sizeof(struct dirent) + namelen)))
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return -EFAULT;
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// ====== 填充dirent结构体 =====
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memset(buf, 0, sizeof(struct dirent) + namelen);
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memcpy(dent->d_name, name, namelen);
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dent->d_name[namelen] = '\0';
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// 暂时不显示目录下的记录数
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dent->d_reclen = 0;
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dent->d_ino = d_ino;
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dent->d_off = offset;
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dent->d_type = type;
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// 返回dirent的总大小
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return sizeof(struct dirent) + namelen;
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}
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/**
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* @brief 创建文件夹
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*
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* @param path 文件夹路径
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* @param mode 创建模式
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* @param from_userland 该创建请求是否来自用户态
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* @return int64_t 错误码
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*/
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int64_t vfs_mkdir(const char* path, mode_t mode, bool from_userland)
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{
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uint32_t pathlen;
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if (from_userland)
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pathlen = strnlen_user(path, PAGE_4K_SIZE - 1);
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else
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pathlen = strnlen(path, PAGE_4K_SIZE - 1);
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if (pathlen == 0)
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return -ENOENT;
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int last_slash = -1;
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// 查找最后一个'/'，忽略路径末尾的'/'
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for (int i = pathlen - 2; i >= 0; --i)
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{
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if (path[i] == '/')
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{
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last_slash = i;
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break;
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}
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}
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// 路径格式不合法（必须使用绝对路径）
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if (last_slash < 0)
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return ENOTDIR;
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char *buf = (char *)kmalloc(last_slash + 1, 0);
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memset(buf, 0, pathlen + 1);
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// 拷贝字符串（不包含要被创建的部分）
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if (from_userland)
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strncpy_from_user(buf, path, last_slash);
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else
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strncpy(buf, path, last_slash);
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buf[last_slash + 1] = '\0';
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// kdebug("to walk: %s", buf);
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// 查找父目录
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struct vfs_dir_entry_t *parent_dir = vfs_path_walk(buf, 0);
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if (parent_dir == NULL)
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{
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kwarn("parent dir is NULL.");
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kfree(buf);
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return -ENOENT;
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}
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kfree(buf);
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// 检查父目录中是否已经有相同的目录项
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if (vfs_path_walk((const char *)path, 0) != NULL)
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{
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// 目录中已有对应的文件夹
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kwarn("Dir '%s' aleardy exists.", path);
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return -EEXIST;
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}
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struct vfs_dir_entry_t *subdir_dentry = (struct vfs_dir_entry_t *)kmalloc(sizeof(struct vfs_dir_entry_t), 0);
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memset((void *)subdir_dentry, 0, sizeof(struct vfs_dir_entry_t));
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list_init(&subdir_dentry->subdirs_list);
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list_init(&subdir_dentry->child_node_list);
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if (path[pathlen - 1] == '/')
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subdir_dentry->name_length = pathlen - last_slash - 2;
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else
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subdir_dentry->name_length = pathlen - last_slash - 1;
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subdir_dentry->name = (char *)kmalloc(subdir_dentry->name_length + 1, 0);
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memset((void *)subdir_dentry->name, 0, subdir_dentry->name_length + 1);
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for (int i = last_slash + 1, cnt = 0; i < pathlen && cnt < subdir_dentry->name_length; ++i, ++cnt)
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{
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subdir_dentry->name[cnt] = path[i];
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}
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++subdir_dentry->name_length;
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// kdebug("last_slash=%d", last_slash);
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// kdebug("name=%s", path + last_slash + 1);
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subdir_dentry->parent = parent_dir;
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// kdebug("to mkdir, parent name=%s", parent_dir->name);
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int retval = parent_dir->dir_inode->inode_ops->mkdir(parent_dir->dir_inode, subdir_dentry, 0);
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list_append(&parent_dir->subdirs_list, &subdir_dentry->child_node_list);
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// kdebug("retval = %d", retval);
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return 0;
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}
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/**
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* @brief 创建文件夹
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*
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* @param path(r8) 路径
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* @param mode(r9) 模式
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* @return uint64_t
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*/
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uint64_t sys_mkdir(struct pt_regs *regs)
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{
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const char *path = (const char *)regs->r8;
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// kdebug("path = %s", path);
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mode_t mode = (mode_t)regs->r9;
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if (regs->cs & USER_CS)
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return vfs_mkdir(path, mode, true);
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else
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return vfs_mkdir(path, mode, false);
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}
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/**
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* @brief 打开文件
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*
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* @param filename 文件路径
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* @param flags 标志位
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* @return uint64_t 错误码
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*/
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uint64_t do_open(const char *filename, int flags)
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{
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long path_len = strnlen_user(filename, PAGE_4K_SIZE) + 1;
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if (path_len <= 0) // 地址空间错误
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{
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return -EFAULT;
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}
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else if (path_len >= PAGE_4K_SIZE) // 名称过长
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{
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return -ENAMETOOLONG;
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}
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// 为待拷贝文件路径字符串分配内存空间
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char *path = (char *)kmalloc(path_len, 0);
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if (path == NULL)
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return -ENOMEM;
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memset(path, 0, path_len);
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strncpy_from_user(path, filename, path_len);
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// 去除末尾的 '/'
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if (path_len >= 2 && path[path_len - 2] == '/')
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{
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path[path_len - 2] = '\0';
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--path_len;
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}
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// 寻找文件
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struct vfs_dir_entry_t *dentry = vfs_path_walk(path, 0);
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// if (dentry != NULL)
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// printk_color(ORANGE, BLACK, "Found %s\nDIR_FstClus:%#018lx\tDIR_FileSize:%#018lx\n", path, ((struct fat32_inode_info_t *)(dentry->dir_inode->private_inode_info))->first_clus, dentry->dir_inode->file_size);
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// else
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// printk_color(ORANGE, BLACK, "Can`t find file\n");
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// kdebug("flags=%#018lx", flags);
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if (dentry == NULL && flags & O_CREAT)
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{
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// 先找到倒数第二级目录
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int tmp_index = -1;
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for (int i = path_len - 1; i >= 0; --i)
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{
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if (path[i] == '/')
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{
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tmp_index = i;
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break;
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}
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}
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struct vfs_dir_entry_t *parent_dentry = NULL;
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// kdebug("tmp_index=%d", tmp_index);
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if (tmp_index > 0)
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{
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path[tmp_index] = '\0';
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dentry = vfs_path_walk(path, 0);
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if (dentry == NULL)
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{
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kfree(path);
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return -ENOENT;
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}
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parent_dentry = dentry;
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}
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else
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parent_dentry = vfs_root_sb->root;
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// 创建新的文件
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dentry = (struct vfs_dir_entry_t *)kmalloc(sizeof(struct vfs_dir_entry_t), 0);
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memset(dentry, 0, sizeof(struct vfs_dir_entry_t));
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dentry->name_length = path_len - tmp_index - 1;
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dentry->name = (char *)kmalloc(dentry->name_length, 0);
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memset(dentry->name, 0, dentry->name_length);
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strncpy(dentry->name, path + tmp_index + 1, dentry->name_length);
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// kdebug("to create new file:%s namelen=%d", dentry->name, dentry->name_length)
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dentry->parent = parent_dentry;
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uint64_t retval = parent_dentry->dir_inode->inode_ops->create(parent_dentry->dir_inode, dentry, 0);
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if (retval != 0)
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{
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kfree(dentry->name);
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kfree(dentry);
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kfree(path);
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return retval;
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}
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list_init(&dentry->child_node_list);
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list_init(&dentry->subdirs_list);
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list_add(&parent_dentry->subdirs_list, &dentry->child_node_list);
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// kdebug("created.");
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}
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kfree(path);
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if (dentry == NULL)
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return -ENOENT;
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// 要求打开文件夹而目标不是文件夹
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if ((flags & O_DIRECTORY) && (dentry->dir_inode->attribute != VFS_ATTR_DIR))
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return -ENOTDIR;
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// // 要找的目标是文件夹
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// if ((flags & O_DIRECTORY) && dentry->dir_inode->attribute == VFS_ATTR_DIR)
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// return -EISDIR;
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// // todo: 引入devfs后删除这段代码
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// // 暂时遇到设备文件的话，就将其first clus设置为特定值
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// if (path_len >= 5 && filename[0] == '/' && filename[1] == 'd' && filename[2] == 'e' && filename[3] == 'v' && filename[4] == '/')
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// {
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// if (dentry->dir_inode->attribute & VFS_ATTR_FILE)
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// {
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// // 对于fat32文件系统上面的设备文件，设置其起始扇区
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// ((struct fat32_inode_info_t *)(dentry->dir_inode->private_inode_info))->first_clus |= 0xf0000000;
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||
// dentry->dir_inode->sb->sb_ops->write_inode(dentry->dir_inode);
|
||
// dentry->dir_inode->attribute |= VFS_ATTR_DEVICE;
|
||
// }
|
||
// }
|
||
|
||
// 创建文件描述符
|
||
struct vfs_file_t *file_ptr = (struct vfs_file_t *)kzalloc(sizeof(struct vfs_file_t), 0);
|
||
|
||
int errcode = -1;
|
||
|
||
file_ptr->dEntry = dentry;
|
||
file_ptr->mode = flags;
|
||
|
||
file_ptr->file_ops = dentry->dir_inode->file_ops;
|
||
|
||
// 如果文件系统实现了打开文件的函数
|
||
if (file_ptr->file_ops && file_ptr->file_ops->open)
|
||
errcode = file_ptr->file_ops->open(dentry->dir_inode, file_ptr);
|
||
|
||
if (errcode != VFS_SUCCESS)
|
||
{
|
||
kfree(file_ptr);
|
||
return -EFAULT;
|
||
}
|
||
|
||
if (file_ptr->mode & O_TRUNC) // 清空文件
|
||
file_ptr->dEntry->dir_inode->file_size = 0;
|
||
|
||
if (file_ptr->mode & O_APPEND)
|
||
file_ptr->position = file_ptr->dEntry->dir_inode->file_size;
|
||
else
|
||
file_ptr->position = 0;
|
||
|
||
struct vfs_file_t **f = current_pcb->fds;
|
||
|
||
int fd_num = -1;
|
||
|
||
// 在指针数组中寻找空位
|
||
// todo: 当pcb中的指针数组改为动态指针数组之后，需要更改这里（目前还是静态指针数组）
|
||
for (int i = 0; i < PROC_MAX_FD_NUM; ++i)
|
||
{
|
||
if (f[i] == NULL) // 找到指针数组中的空位
|
||
{
|
||
fd_num = i;
|
||
break;
|
||
}
|
||
}
|
||
|
||
// 指针数组没有空位了
|
||
if (fd_num == -1)
|
||
{
|
||
kfree(file_ptr);
|
||
return -EMFILE;
|
||
}
|
||
// 保存文件描述符
|
||
f[fd_num] = file_ptr;
|
||
return fd_num;
|
||
}
|
||
|
||
uint64_t sys_open(struct pt_regs *regs)
|
||
{
|
||
char *filename = (char *)(regs->r8);
|
||
int flags = (int)(regs->r9);
|
||
|
||
return do_open(filename, flags);
|
||
}
|
||
|
||
/**
|
||
* @brief 动态分配dentry以及路径字符串名称
|
||
*
|
||
* @param name_size 名称字符串大小（字节）(注意考虑字符串最后需要有一个‘\0’作为结尾)
|
||
* @return struct vfs_dir_entry_t* 创建好的dentry
|
||
*/
|
||
struct vfs_dir_entry_t *vfs_alloc_dentry(const int name_size)
|
||
{
|
||
if (unlikely(name_size > VFS_MAX_PATHLEN))
|
||
return NULL;
|
||
struct vfs_dir_entry_t *dentry = (struct vfs_dir_entry_t *)kzalloc(sizeof(struct vfs_dir_entry_t), 0);
|
||
dentry->name = (char *)kzalloc(name_size, 0);
|
||
list_init(&dentry->child_node_list);
|
||
list_init(&dentry->subdirs_list);
|
||
return dentry;
|
||
}
|
||
|
||
/**
|
||
* @brief 初始化vfs
|
||
*
|
||
* @return int 错误码
|
||
*/
|
||
int vfs_init()
|
||
{
|
||
mount_init();
|
||
return 0;
|
||
} |