add directory kernel

kernel/0.95/linux-0.95/fs/read_write.c

@@ -0,0 +1,97 @@
+/*
+ *  linux/fs/read_write.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#include <sys/stat.h>
+#include <errno.h>
+#include <sys/types.h>
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <asm/segment.h>
+
+int sys_lseek(unsigned int fd,off_t offset, unsigned int origin)
+{
+	struct file * file;
+	int tmp;
+
+	if (fd >= NR_OPEN || !(file=current->filp[fd]) || !(file->f_inode))
+		return -EBADF;
+	if (origin > 2)
+		return -EINVAL;
+	if (file->f_inode->i_pipe)
+		return -ESPIPE;
+	if (file->f_op && file->f_op->lseek)
+		return file->f_op->lseek(file->f_inode,file,offset,origin);
+/* this is the default handler if no lseek handler is present */
+	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;
+	}
+	return file->f_pos;
+}
+
+int sys_read(unsigned int fd,char * buf,unsigned int count)
+{
+	struct file * file;
+	struct inode * inode;
+
+	if (fd>=NR_OPEN || !(file=current->filp[fd]) || !(inode=file->f_inode))
+		return -EBADF;
+	if (!(file->f_mode & 1))
+		return -EBADF;
+	if (!count)
+		return 0;
+	verify_area(buf,count);
+	if (file->f_op && file->f_op->read)
+		return file->f_op->read(inode,file,buf,count);
+/* these are the default read-functions */
+	if (inode->i_pipe)
+		return pipe_read(inode,file,buf,count);
+	if (S_ISCHR(inode->i_mode))
+		return char_read(inode,file,buf,count);
+	if (S_ISBLK(inode->i_mode))
+		return block_read(inode,file,buf,count);
+	if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode))
+		return minix_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,unsigned int count)
+{
+	struct file * file;
+	struct inode * inode;
+	
+	if (fd>=NR_OPEN || !(file=current->filp[fd]) || !(inode=file->f_inode))
+		return -EBADF;
+	if (!(file->f_mode&2))
+		return -EBADF;
+	if (!count)
+		return 0;
+	if (file->f_op && file->f_op->write)
+		return file->f_op->write(inode,file,buf,count);
+/* these are the default read-functions */
+	if (inode->i_pipe)
+		return pipe_write(inode,file,buf,count);
+	if (S_ISCHR(inode->i_mode))
+		return char_write(inode,file,buf,count);
+	if (S_ISBLK(inode->i_mode))
+		return block_write(inode,file,buf,count);
+	if (S_ISREG(inode->i_mode))
+		return minix_file_write(inode,file,buf,count);
+	printk("(Write)inode->i_mode=%06o\n\r",inode->i_mode);
+	return -EINVAL;
+}