// 我们来看一下复制files_struct的函数dup_fs
int
dup_fs(struct files_struct *to, struct files_struct *from) {
// cprintf("[dup_fs]\n");
assert(to != NULL && from != NULL);
assert(files_count(to) == 0 && files_count(from) > 0);
if ((to->pwd = from->pwd) != NULL) {
vop_ref_inc(to->pwd); // 增加引用就可以了
}
int i;
struct file *to_file = to->fd_array, *from_file = from->fd_array;
for (i = 0; i < FILES_STRUCT_NENTRY; i ++, to_file ++, from_file ++) {
if (from_file->status == FD_OPENED) {
/* alloc_fd first */
to_file->status = FD_INIT;
fd_array_dup(to_file, from_file);
}
}
return 0;
}
void
files_closeall(struct files_struct *filesp) {
// cprintf("[files_closeall]\n");
assert(filesp != NULL && files_count(filesp) > 0);
int i;
struct file *file = filesp->fd_array;
//skip the stdin & stdout
for (i = 2, file += 2; i < FILES_STRUCT_NENTRY; i ++, file ++) {
if (file->status == FD_OPENED) {
fd_array_close(file);
}
}
}
//Called when a proc exit
void
files_destroy(struct files_struct *filesp) { // 用于销毁文件
// cprintf("[files_destroy]\n");
assert(filesp != NULL && files_count(filesp) == 0);
if (filesp->pwd != NULL) { // 如果当前目录不为空
vop_ref_dec(filesp->pwd);
}
int i;
struct file *file = filesp->fd_array;
for (i = 0; i < FILES_STRUCT_NENTRY; i ++, file ++) {
if (file->status == FD_OPENED) {
fd_array_close(file); // 关闭每一个文件
}
assert(file->status == FD_NONE);
}
kfree(filesp);
}
// get_fd_array - get current process's open files table
static struct file *
get_fd_array(void) {
struct files_struct *filesp = current->filesp;
assert(filesp != NULL && files_count(filesp) > 0);
return filesp->fd_array;
}
