《操作系统》的实验代码。
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#include <defs.h>
#include <string.h>
#include <vfs.h>
#include <inode.h>
#include <unistd.h>
#include <error.h>
#include <assert.h>
// open file in vfs, get/create inode for file with filename path.
int
vfs_open(char *path, uint32_t open_flags, struct inode **node_store) {
bool can_write = 0;
switch (open_flags & O_ACCMODE) {
case O_RDONLY:
break;
case O_WRONLY:
case O_RDWR:
can_write = 1;
break;
default:
return -E_INVAL;
}
if (open_flags & O_TRUNC) {
if (!can_write) {
return -E_INVAL;
}
}
int ret;
struct inode *node;
bool excl = (open_flags & O_EXCL) != 0;
bool create = (open_flags & O_CREAT) != 0;
ret = vfs_lookup(path, &node);
if (ret != 0) {
if (ret == -16 && (create)) {
char *name;
struct inode *dir;
if ((ret = vfs_lookup_parent(path, &dir, &name)) != 0) {
return ret;
}
ret = vop_create(dir, name, excl, &node);
} else return ret;
} else if (excl && create) {
return -E_EXISTS;
}
assert(node != NULL);
if ((ret = vop_open(node, open_flags)) != 0) {
vop_ref_dec(node);
return ret;
}
vop_open_inc(node);
if (open_flags & O_TRUNC || create) {
if ((ret = vop_truncate(node, 0)) != 0) {
vop_open_dec(node);
vop_ref_dec(node);
return ret;
}
}
*node_store = node;
return 0;
}
// close file in vfs
int
vfs_close(struct inode *node) {
vop_open_dec(node);
vop_ref_dec(node);
return 0;
}
// unimplement
int
vfs_unlink(char *path) {
return -E_UNIMP;
}
// unimplement
int
vfs_rename(char *old_path, char *new_path) {
return -E_UNIMP;
}
// unimplement
int
vfs_link(char *old_path, char *new_path) {
return -E_UNIMP;
}
// unimplement
int
vfs_symlink(char *old_path, char *new_path) {
return -E_UNIMP;
}
// unimplement
int
vfs_readlink(char *path, struct iobuf *iob) {
return -E_UNIMP;
}
// unimplement
int
vfs_mkdir(char *path){
return -E_UNIMP;
}