Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/syscalls.h | 2 ++
2 files changed, 47 insertions(+), 0 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 9c8d4cc..1259721 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2695,6 +2695,51 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
+SYSCALL_DEFINE4(handle_link, int, mountdirfd, struct file_handle __user *, uofh,
+ int, newdfd, const char __user *, newname)
+{
+ char *to;
+ int error;
+ struct dentry *new_dentry;
+ struct nameidata nd;
+ struct path old_path;
+
+ error = handle_to_path(mountdirfd, uofh, &old_path);
+ if (error)
+ return error;
+
+ error = user_path_parent(newdfd, newname, &nd, &to);
+ if (error)
+ goto out;
+ error = -EXDEV;
+ if (old_path.mnt != nd.path.mnt)
+ goto out_release;
+ new_dentry = lookup_create(&nd, 0);
+ error = PTR_ERR(new_dentry);
+ if (IS_ERR(new_dentry))
+ goto out_unlock;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto out_dput;
+ error = security_path_link(old_path.dentry, &nd.path, new_dentry);
+ if (error)
+ goto out_drop_write;
+ error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
+out_drop_write:
+ mnt_drop_write(nd.path.mnt);
+out_dput:
+ dput(new_dentry);
+out_unlock:
+ mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+out_release:
+ path_put(&nd.path);
+ putname(to);
+out:
+ path_put(&old_path);
+
+ return error;
+}
+
/*
* The worst of all namespace operations - renaming directory. "Perverted"
* doesn't even start to describe it. Somebody in UCB had a heck of a trip...
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index dd1d994..7d4e6a4 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -851,4 +851,6 @@ asmlinkage long sys_handle_stat(int mountdirfd,
struct file_handle __user *ufh,
struct stat __user *statbuf);
#endif
+asmlinkage long sys_handle_link(int mountdirfd, struct file_handle __user *uofh,
+ int newfd, const char __user *newname);
#endif
--
1.7.1
--
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