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Code Issues Releases Wiki Activity

Devfs初步实现 (#41)

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* new: 在devfs中使用键盘文件（仍存在bug）

* new:支持dev目录下的readdir
This commit is contained in:
login
2022-09-07 23:27:27 +08:00
committed by GitHub
parent 86a5f25e07
commit 7d44599447
16 changed files with 683 additions and 215 deletions
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330
kernel/filesystem/VFS/VFS.c
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@ -1,4 +1,5 @@
#include "VFS.h"
#include "mount.h"
#include <common/kprint.h>
#include <common/dirent.h>
#include <common/string.h>
@ -8,6 +9,9 @@
#include <process/ptrace.h>
#include <process/process.h>
// todo: devfs完善后，删除这个
extern struct vfs_file_operations_t ps2_keyboard_fops;
// 为filesystem_type_t结构体实例化一个链表头
static struct vfs_filesystem_type_t vfs_fs = {"filesystem", 0};
struct vfs_superblock_t *vfs_root_sb = NULL;
@ -23,6 +27,16 @@ struct vfs_superblock_t *vfs_root_sb = NULL;
struct vfs_superblock_t *vfs_mount_fs(const char *path, char *name, struct block_device *blk)
{
// todo: 选择挂载点
// 判断挂载点是否存在
struct vfs_dir_entry_t *target_dentry = NULL;
// 由于目前还没有rootfs，因此挂载根目录时，不需要path walk
if (strcmp(path, "/") != 0)
{
target_dentry = vfs_path_walk(path, 0);
if (target_dentry == NULL)
return NULL;
}
struct vfs_filesystem_type_t *p = NULL;
for (p = &vfs_fs; p; p = p->next)
{
@ -31,6 +45,17 @@ struct vfs_superblock_t *vfs_mount_fs(const char *path, char *name, struct block
struct vfs_superblock_t *sb = p->read_superblock(blk);
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
vfs_root_sb = sb;
else
{
kdebug("to mount %s", name);
// 调用mount机制，挂载文件系统
struct vfs_dir_entry_t *new_dentry = sb->root;
// 注意，umount的时候需要释放这些内存
new_dentry->name = kzalloc(target_dentry->name_length + 1, 0);
new_dentry->name_length = target_dentry->name_length;
do_mount(target_dentry, new_dentry);
}
return sb;
}
}
@ -76,6 +101,31 @@ uint64_t vfs_unregister_filesystem(struct vfs_filesystem_type_t *fs)
return VFS_E_FS_NOT_EXIST;
}
/**
* @brief 在dentry的sub_dir_list中搜索指定名称的dentry
*
* @param dentry 目录项结构体dentry
* @param name 待搜索的dentry名称
* @return struct vfs_dir_entry_t* 目标dentry （无结果则返回NULL）
*/
static struct vfs_dir_entry_t *vfs_search_dentry_list(struct vfs_dir_entry_t *dentry, const char *name)
{
if (list_empty(&dentry->subdirs_list))
return NULL;
struct List *ptr = &dentry->subdirs_list;
struct vfs_dir_entry_t *d_ptr = NULL;
do
{
ptr = list_next(ptr);
d_ptr = container_of(ptr, struct vfs_dir_entry_t, child_node_list);
if (strcmp(name, d_ptr->name) == 0)
return d_ptr;
} while (list_next(ptr) != (&dentry->subdirs_list));
return NULL;
}
/**
* @brief 按照路径查找文件
*
@ -94,42 +144,56 @@ struct vfs_dir_entry_t *vfs_path_walk(const char *path, uint64_t flags)
if ((!*path) || (*path == '\0'))
return parent;
struct vfs_dir_entry_t *dentry;
struct vfs_dir_entry_t *dentry = NULL;
// kdebug("path before walk:%s", path);
while (true)
{
// 提取出下一级待搜索的目录名或文件名，并保存在dEntry_name中
const char *tmp_path = path;
char *tmp_path = path;
while ((*path && *path != '\0') && (*path != '/'))
++path;
int tmp_path_len = path - tmp_path;
dentry = (struct vfs_dir_entry_t *)kmalloc(sizeof(struct vfs_dir_entry_t), 0);
memset(dentry, 0, sizeof(struct vfs_dir_entry_t));
// 为目录项的名称分配内存
dentry->name = (char *)kmalloc(tmp_path_len + 1, 0);
// 貌似这里不需要memset，因为空间会被覆盖
// memset(dentry->name, 0, tmp_path_len+1);
memcpy(dentry->name, (void *)tmp_path, tmp_path_len);
dentry->name[tmp_path_len] = '\0';
// kdebug("tmp_path_len=%d, dentry->name= %s", tmp_path_len, dentry->name);
dentry->name_length = tmp_path_len;
if (parent->dir_inode->inode_ops->lookup(parent->dir_inode, dentry) == NULL)
// 搜索是否有dentry缓存
{
// 搜索失败
// kerror("cannot find the file/dir : %s", dentry->name);
kfree(dentry->name);
kfree(dentry);
return NULL;
char bk = *(tmp_path + tmp_path_len);
*(tmp_path + tmp_path_len) = '\0';
// kdebug("to search:%s", tmp_path);
dentry = vfs_search_dentry_list(parent, tmp_path);
// kdebug("search done, dentry=%#018lx", dentry);
*(tmp_path + tmp_path_len) = bk;
}
// 如果没有找到dentry缓存，则申请新的dentry
if (dentry == NULL)
{
dentry = (struct vfs_dir_entry_t *)kzalloc(sizeof(struct vfs_dir_entry_t), 0);
// 为目录项的名称分配内存
dentry->name = (char *)kmalloc(tmp_path_len + 1, 0);
// 貌似这里不需要memset，因为空间会被覆盖
// memset(dentry->name, 0, tmp_path_len+1);
memcpy(dentry->name, (void *)tmp_path, tmp_path_len);
dentry->name[tmp_path_len] = '\0';
// kdebug("tmp_path_len=%d, dentry->name= %s", tmp_path_len, dentry->name);
dentry->name_length = tmp_path_len;
if (parent->dir_inode->inode_ops->lookup(parent->dir_inode, dentry) == NULL)
{
// 搜索失败
// kerror("cannot find the file/dir : %s", dentry->name);
kfree(dentry->name);
kfree(dentry);
return NULL;
}
// 找到子目录项
// 初始化子目录项的entry
list_init(&dentry->child_node_list);
list_init(&dentry->subdirs_list);
dentry->parent = parent;
list_add(&parent->subdirs_list, &dentry->child_node_list);
}
// 找到子目录项
// 初始化子目录项的entry
list_init(&dentry->child_node_list);
list_init(&dentry->subdirs_list);
dentry->parent = parent;
list_add(&parent->subdirs_list, &dentry->child_node_list);
while (*path == '/')
++path;
@ -151,7 +215,7 @@ struct vfs_dir_entry_t *vfs_path_walk(const char *path, uint64_t flags)
* @brief 填充dentry
*
*/
int vfs_fill_dentry(void *buf, ino_t d_ino, char *name, int namelen, unsigned char type, off_t offset)
int vfs_fill_dirent(void *buf, ino_t d_ino, char *name, int namelen, unsigned char type, off_t offset)
{
struct dirent *dent = (struct dirent *)buf;
@ -264,4 +328,216 @@ uint64_t sys_mkdir(struct pt_regs *regs)
list_add(&parent_dir->subdirs_list, &subdir_dentry->child_node_list);
// kdebug("retval = %d", retval);
return 0;
}
/**
* @brief 打开文件
*
* @param filename 文件路径
* @param flags 标志位
* @return uint64_t 错误码
*/
uint64_t do_open(const char *filename, int flags)
{
long path_len = strnlen_user(filename, PAGE_4K_SIZE) + 1;
if (path_len <= 0) // 地址空间错误
{
return -EFAULT;
}
else if (path_len >= PAGE_4K_SIZE) // 名称过长
{
return -ENAMETOOLONG;
}
// 为待拷贝文件路径字符串分配内存空间
char *path = (char *)kmalloc(path_len, 0);
if (path == NULL)
return -ENOMEM;
memset(path, 0, path_len);
strncpy_from_user(path, filename, path_len);
// 去除末尾的 '/'
if (path_len >= 2 && path[path_len - 2] == '/')
{
path[path_len - 2] = '\0';
--path_len;
}
// 寻找文件
struct vfs_dir_entry_t *dentry = vfs_path_walk(path, 0);
// if (dentry != NULL)
// 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);
// else
// printk_color(ORANGE, BLACK, "Can`t find file\n");
// kdebug("flags=%#018lx", flags);
if (dentry == NULL && flags & O_CREAT)
{
// 先找到倒数第二级目录
int tmp_index = -1;
for (int i = path_len - 1; i >= 0; --i)
{
if (path[i] == '/')
{
tmp_index = i;
break;
}
}
struct vfs_dir_entry_t *parent_dentry = NULL;
// kdebug("tmp_index=%d", tmp_index);
if (tmp_index > 0)
{
path[tmp_index] = '\0';
dentry = vfs_path_walk(path, 0);
if (dentry == NULL)
{
kfree(path);
return -ENOENT;
}
parent_dentry = dentry;
}
else
parent_dentry = vfs_root_sb->root;
// 创建新的文件
dentry = (struct vfs_dir_entry_t *)kmalloc(sizeof(struct vfs_dir_entry_t), 0);
memset(dentry, 0, sizeof(struct vfs_dir_entry_t));
dentry->name_length = path_len - tmp_index - 1;
dentry->name = (char *)kmalloc(dentry->name_length, 0);
memset(dentry->name, 0, dentry->name_length);
strncpy(dentry->name, path + tmp_index + 1, dentry->name_length);
// kdebug("to create new file:%s namelen=%d", dentry->name, dentry->name_length)
dentry->parent = parent_dentry;
uint64_t retval = parent_dentry->dir_inode->inode_ops->create(parent_dentry->dir_inode, dentry, 0);
if (retval != 0)
{
kfree(dentry->name);
kfree(dentry);
kfree(path);
return retval;
}
list_init(&dentry->child_node_list);
list_init(&dentry->subdirs_list);
list_add(&parent_dentry->subdirs_list, &dentry->child_node_list);
// kdebug("created.");
}
kfree(path);
if (dentry == NULL)
return -ENOENT;
// 要求打开文件夹而目标不是文件夹
if ((flags & O_DIRECTORY) && (dentry->dir_inode->attribute != VFS_ATTR_DIR))
return -ENOTDIR;
// // 要找的目标是文件夹
// if ((flags & O_DIRECTORY) && dentry->dir_inode->attribute == VFS_ATTR_DIR)
// return -EISDIR;
// // todo: 引入devfs后删除这段代码
// // 暂时遇到设备文件的话，就将其first clus设置为特定值
// if (path_len >= 5 && filename[0] == '/' && filename[1] == 'd' && filename[2] == 'e' && filename[3] == 'v' && filename[4] == '/')
// {
// if (dentry->dir_inode->attribute & VFS_ATTR_FILE)
// {
// // 对于fat32文件系统上面的设备文件，设置其起始扇区
// ((struct fat32_inode_info_t *)(dentry->dir_inode->private_inode_info))->first_clus |= 0xf0000000;
// 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;
}