// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>

#include <uapi/linux/io_uring.h>

#include "../fs/internal.h"

#include "io_uring.h"
#include "fs.h"

struct io_rename {
        struct file                     *file;
        int                             old_dfd;
        int                             new_dfd;
        struct delayed_filename         oldpath;
        struct delayed_filename         newpath;
        int                             flags;
};

struct io_unlink {
        struct file                     *file;
        int                             dfd;
        int                             flags;
        struct delayed_filename         filename;
};

struct io_mkdir {
        struct file                     *file;
        int                             dfd;
        umode_t                         mode;
        struct delayed_filename         filename;
};

struct io_link {
        struct file                     *file;
        int                             old_dfd;
        int                             new_dfd;
        struct delayed_filename         oldpath;
        struct delayed_filename         newpath;
        int                             flags;
};

int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
        const char __user *oldf, *newf;
        int err;

        if (sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
        if (unlikely(req->flags & REQ_F_FIXED_FILE))
                return -EBADF;

        ren->old_dfd = READ_ONCE(sqe->fd);
        oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
        newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
        ren->new_dfd = READ_ONCE(sqe->len);
        ren->flags = READ_ONCE(sqe->rename_flags);

        err = delayed_getname(&ren->oldpath, oldf);
        if (unlikely(err))
                return err;

        err = delayed_getname(&ren->newpath, newf);
        if (unlikely(err)) {
                dismiss_delayed_filename(&ren->oldpath);
                return err;
        }

        req->flags |= REQ_F_NEED_CLEANUP;
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
}

int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
        CLASS(filename_complete_delayed, old)(&ren->oldpath);
        CLASS(filename_complete_delayed, new)(&ren->newpath);
        int ret;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

        ret = filename_renameat2(ren->old_dfd, old,
                                 ren->new_dfd, new, ren->flags);

        req->flags &= ~REQ_F_NEED_CLEANUP;
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

void io_renameat_cleanup(struct io_kiocb *req)
{
        struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);

        dismiss_delayed_filename(&ren->oldpath);
        dismiss_delayed_filename(&ren->newpath);
}

int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
        const char __user *fname;
        int err;

        if (sqe->off || sqe->len || sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
        if (unlikely(req->flags & REQ_F_FIXED_FILE))
                return -EBADF;

        un->dfd = READ_ONCE(sqe->fd);

        un->flags = READ_ONCE(sqe->unlink_flags);
        if (un->flags & ~AT_REMOVEDIR)
                return -EINVAL;

        fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
        err = delayed_getname(&un->filename, fname);
        if (unlikely(err))
                return err;

        req->flags |= REQ_F_NEED_CLEANUP;
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
}

int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
        CLASS(filename_complete_delayed, name)(&un->filename);
        int ret;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

        if (un->flags & AT_REMOVEDIR)
                ret = filename_rmdir(un->dfd, name);
        else
                ret = filename_unlinkat(un->dfd, name);

        req->flags &= ~REQ_F_NEED_CLEANUP;
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

void io_unlinkat_cleanup(struct io_kiocb *req)
{
        struct io_unlink *ul = io_kiocb_to_cmd(req, struct io_unlink);

        dismiss_delayed_filename(&ul->filename);
}

int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
        const char __user *fname;
        int err;

        if (sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
        if (unlikely(req->flags & REQ_F_FIXED_FILE))
                return -EBADF;

        mkd->dfd = READ_ONCE(sqe->fd);
        mkd->mode = READ_ONCE(sqe->len);

        fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
        err = delayed_getname(&mkd->filename, fname);
        if (unlikely(err))
                return err;

        req->flags |= REQ_F_NEED_CLEANUP;
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
}

int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
        CLASS(filename_complete_delayed, name)(&mkd->filename);
        int ret;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

        ret = filename_mkdirat(mkd->dfd, name, mkd->mode);

        req->flags &= ~REQ_F_NEED_CLEANUP;
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

void io_mkdirat_cleanup(struct io_kiocb *req)
{
        struct io_mkdir *md = io_kiocb_to_cmd(req, struct io_mkdir);

        dismiss_delayed_filename(&md->filename);
}

int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
        const char __user *oldpath, *newpath;
        int err;

        if (sqe->len || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
        if (unlikely(req->flags & REQ_F_FIXED_FILE))
                return -EBADF;

        sl->new_dfd = READ_ONCE(sqe->fd);
        oldpath = u64_to_user_ptr(READ_ONCE(sqe->addr));
        newpath = u64_to_user_ptr(READ_ONCE(sqe->addr2));

        err = delayed_getname(&sl->oldpath, oldpath);
        if (unlikely(err))
                return err;

        err = delayed_getname(&sl->newpath, newpath);
        if (unlikely(err)) {
                dismiss_delayed_filename(&sl->oldpath);
                return err;
        }

        req->flags |= REQ_F_NEED_CLEANUP;
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
}

int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
        CLASS(filename_complete_delayed, old)(&sl->oldpath);
        CLASS(filename_complete_delayed, new)(&sl->newpath);
        int ret;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

        ret = filename_symlinkat(old, sl->new_dfd, new);

        req->flags &= ~REQ_F_NEED_CLEANUP;
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
        const char __user *oldf, *newf;
        int err;

        if (sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
        if (unlikely(req->flags & REQ_F_FIXED_FILE))
                return -EBADF;

        lnk->old_dfd = READ_ONCE(sqe->fd);
        lnk->new_dfd = READ_ONCE(sqe->len);
        oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
        newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
        lnk->flags = READ_ONCE(sqe->hardlink_flags);

        err = delayed_getname_uflags(&lnk->oldpath, oldf, lnk->flags);
        if (unlikely(err))
                return err;

        err = delayed_getname(&lnk->newpath, newf);
        if (unlikely(err)) {
                dismiss_delayed_filename(&lnk->oldpath);
                return err;
        }

        req->flags |= REQ_F_NEED_CLEANUP;
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
}

int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
        CLASS(filename_complete_delayed, old)(&lnk->oldpath);
        CLASS(filename_complete_delayed, new)(&lnk->newpath);
        int ret;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

        ret = filename_linkat(lnk->old_dfd, old, lnk->new_dfd, new, lnk->flags);

        req->flags &= ~REQ_F_NEED_CLEANUP;
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

void io_link_cleanup(struct io_kiocb *req)
{
        struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);

        dismiss_delayed_filename(&sl->oldpath);
        dismiss_delayed_filename(&sl->newpath);
}