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Code Issues Releases Wiki Activity

🆕 lseek系统调用

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This commit is contained in:
fslongjin
2022-05-03 15:40:23 +08:00
parent f99179014a
commit 2ed8bdcfd2
6 changed files with 120 additions and 10 deletions
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46
kernel/filesystem/fat32/fat32.c
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@ -5,6 +5,7 @@
#include <process/spinlock.h>
#include <mm/slab.h>
#include <common/errno.h>
#include <common/stdio.h>
struct vfs_super_block_operations_t fat32_sb_ops;
struct vfs_dir_entry_operations_t fat32_dEntry_ops;
@ -484,8 +485,7 @@ void fat32_write_inode(struct vfs_index_node_t *inode)
// 计算目标inode对应数据区的LBA地址
uint64_t fLBA = fsbi->first_data_sector + (finode->dEntry_location_clus - 2) * fsbi->sec_per_clus;
kdebug("fLBA=%d", fLBA);
kdebug("fsbi->first_data_sector=%d", fsbi->first_data_sector);
struct fat32_Directory_t *buf = (struct fat32_Directory_t *)kmalloc(fsbi->bytes_per_clus, 0);
memset(buf, 0, fsbi->bytes_per_clus);
@ -495,13 +495,11 @@ void fat32_write_inode(struct vfs_index_node_t *inode)
struct fat32_Directory_t *fdEntry = buf + finode->dEntry_location_clus_offset;
// 写入fat32文件系统的dir_entry
kdebug("inode->file_size=%#018lx", inode->file_size);
kdebug("before fdEntry->DIR_FileSize=%d", fdEntry->DIR_FileSize);
fdEntry->DIR_FileSize = inode->file_size;
fdEntry->DIR_FstClusLO = finode->first_clus & 0xffff;
fdEntry->DIR_FstClusHI = (finode->first_clus >> 16) | (fdEntry->DIR_FstClusHI & 0xf000);
kdebug("middle fdEntry->DIR_FileSize=%d", fdEntry->DIR_FileSize);
// 将dir entry写回磁盘
ahci_operation.transfer(AHCI_CMD_WRITE_DMA_EXT, fLBA, fsbi->sec_per_clus, (uint64_t)buf, fsbi->ahci_ctrl_num, fsbi->ahci_port_num);
@ -812,9 +810,43 @@ long fat32_write(struct vfs_file_t *file_ptr, char *buf, int64_t count, long *po
// kdebug("retval=%lld", retval);
return retval;
}
// todo: lseek
long fat32_lseek(struct vfs_file_t *file_ptr, long offset, long origin)
/**
* @brief 调整文件的当前访问位置
*
* @param file_ptr vfs文件指针
* @param offset 调整的偏移量
* @param whence 调整方法
* @return long 更新后的指针位置
*/
long fat32_lseek(struct vfs_file_t *file_ptr, long offset, long whence)
{
struct vfs_index_node_t *inode = file_ptr->dEntry->dir_inode;
long pos = 0;
switch (whence)
{
case SEEK_SET: // 相对于文件头
pos = offset;
break;
case SEEK_CUR: // 相对于当前位置
pos = file_ptr->position + offset;
break;
case SEEK_END: // 相对于文件末尾
pos = file_ptr->dEntry->dir_inode->file_size + offset;
break;
default:
return -EINVAL;
break;
}
if(pos<0||pos>file_ptr->dEntry->dir_inode->file_size)
return -EOVERFLOW;
file_ptr->position = pos;
kdebug("fat32 lseek -> position=%d", file_ptr->position);
return pos;
}
// todo: ioctl
long fat32_ioctl(struct vfs_index_node_t *inode, struct vfs_file_t *file_ptr, uint64_t cmd, uint64_t arg)