diff --git a/read_write.c b/read_write.c new file mode 100644 index 0000000..3b437ac --- /dev/null +++ b/read_write.c @@ -0,0 +1,152 @@ +/* + * linux/fs/read_write.c + * + * (C) 1991 Linus Torvalds + */ + +#include +#include +#include + +#include +#include +#include +#include +extern int rw_char(int rw,int dev, char * buf, int count, off_t * pos); +extern int read_pipe(struct m_inode * inode, char * buf, int count); +extern int write_pipe(struct m_inode * inode, char * buf, int count); +extern int block_read(int dev, off_t * pos, char * buf, int count); +extern int block_write(int dev, off_t * pos, char * buf, int count); +extern int file_read(struct m_inode * inode, struct file * filp, + char * buf, int count); +extern int file_write(struct m_inode * inode, struct file * filp, + char * buf, int count); + +int sys_lseek(unsigned int fd,off_t offset, int origin) +{ + struct file * file; + int tmp; + + if (fd >= NR_OPEN || !(file=current->filp[fd]) || !(file->f_inode) + || !IS_SEEKABLE(MAJOR(file->f_inode->i_dev))) + return -EBADF; + if (file->f_inode->i_pipe) + return -ESPIPE; + switch (origin) { + case 0: + if (offset<0) return -EINVAL; + file->f_pos=offset; + break; + case 1: + if (file->f_pos+offset<0) return -EINVAL; + file->f_pos += offset; + break; + case 2: + if ((tmp=file->f_inode->i_size+offset) < 0) + return -EINVAL; + file->f_pos = tmp; + break; + default: + return -EINVAL; + } + return file->f_pos; +} + +int sys_read(unsigned int fd,char * buf,int count) +{ + struct file * file; + struct m_inode * inode; + + if (fd>=NR_OPEN || count<0 || !(file=current->filp[fd])) + return -EINVAL; + if (!count) + return 0; + verify_area(buf,count); + inode = file->f_inode; + if (inode->i_pipe) + return (file->f_mode&1)?read_pipe(inode,buf,count):-EIO; + if (S_ISCHR(inode->i_mode)) + return rw_char(READ,inode->i_zone[0],buf,count,&file->f_pos); + if (S_ISBLK(inode->i_mode)) + return block_read(inode->i_zone[0],&file->f_pos,buf,count); + if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode)) { + if (count+file->f_pos > inode->i_size) + count = inode->i_size - file->f_pos; + if (count<=0) + return 0; + return file_read(inode,file,buf,count); + } + printk("(Read)inode->i_mode=%06o\n\r",inode->i_mode); + return -EINVAL; +} +int k_read(unsigned int fd,char * buf,int count) +{ + struct file * file; + struct m_inode * inode; + + if (fd>=NR_OPEN || count<0 || !(file=current->filp[fd])) + return -EINVAL; + if (!count) + return 0; + verify_area(buf,count); + inode = file->f_inode; + if (inode->i_pipe) + return (file->f_mode&1)?read_pipe(inode,buf,count):-EIO; + if (S_ISCHR(inode->i_mode)) + return rw_char(READ,inode->i_zone[0],buf,count,&file->f_pos); + if (S_ISBLK(inode->i_mode)) + return block_read(inode->i_zone[0],&file->f_pos,buf,count); + if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode)) { + if (count+file->f_pos > inode->i_size) + count = inode->i_size - file->f_pos; + if (count<=0) + return 0; + return k_file_read(inode,file,buf,count); + } + printk("(Read)inode->i_mode=%06o\n\r",inode->i_mode); + return -EINVAL; +} +int sys_write(unsigned int fd,char * buf,int count) +{ + struct file * file; + struct m_inode * inode; + + if (fd>=NR_OPEN || count <0 || !(file=current->filp[fd])) + return -EINVAL; + if (!count) + return 0; + inode=file->f_inode; + if (inode->i_pipe) + return (file->f_mode&2)?write_pipe(inode,buf,count):-EIO; + if (S_ISCHR(inode->i_mode)) + return rw_char(WRITE,inode->i_zone[0],buf,count,&file->f_pos); + if (S_ISBLK(inode->i_mode)) + return block_write(inode->i_zone[0],&file->f_pos,buf,count); + if (S_ISREG(inode->i_mode)) + return file_write(inode,file,buf,count); + printk("(Write)inode->i_mode=%06o\n\r",inode->i_mode); + return -EINVAL; +} +int sys_getdents(unsigned int fd, struct linux_dirent *dirp, unsigned long count) +{ + char name[16]; + int i=0,j=0; + int rst=count; + + while(k_read(fd,name,16)>0 && name[0] && count-32>0) + { + put_fs_long(name, &(dirp->d_ino)); + i++; + put_fs_long(i,&(dirp->d_off)); + put_fs_word(32,&(dirp->d_reclen)); + + for(j=0;j<14;j++) + { + put_fs_byte(name[j+2],dirp->d_name+j); + } + count-=32; + dirp=(struct linux_dirent*)((char *)dirp+32); + } + return rst-count; +} +