linux/io_uring/openclose.c
Stefan Metzmacher f2ccb5aed7 io_uring: make io_kiocb_to_cmd() typesafe
We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-12 17:01:00 -06:00

257 lines
6.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fsnotify.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 "rsrc.h"
#include "openclose.h"
struct io_open {
struct file *file;
int dfd;
u32 file_slot;
struct filename *filename;
struct open_how how;
unsigned long nofile;
};
struct io_close {
struct file *file;
int fd;
u32 file_slot;
};
static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
const char __user *fname;
int ret;
if (unlikely(sqe->buf_index))
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
/* open.how should be already initialised */
if (!(open->how.flags & O_PATH) && force_o_largefile())
open->how.flags |= O_LARGEFILE;
open->dfd = READ_ONCE(sqe->fd);
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
open->filename = getname(fname);
if (IS_ERR(open->filename)) {
ret = PTR_ERR(open->filename);
open->filename = NULL;
return ret;
}
open->file_slot = READ_ONCE(sqe->file_index);
if (open->file_slot && (open->how.flags & O_CLOEXEC))
return -EINVAL;
open->nofile = rlimit(RLIMIT_NOFILE);
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
u64 mode = READ_ONCE(sqe->len);
u64 flags = READ_ONCE(sqe->open_flags);
open->how = build_open_how(flags, mode);
return __io_openat_prep(req, sqe);
}
int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
struct open_how __user *how;
size_t len;
int ret;
how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
len = READ_ONCE(sqe->len);
if (len < OPEN_HOW_SIZE_VER0)
return -EINVAL;
ret = copy_struct_from_user(&open->how, sizeof(open->how), how, len);
if (ret)
return ret;
return __io_openat_prep(req, sqe);
}
int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
struct open_flags op;
struct file *file;
bool resolve_nonblock, nonblock_set;
bool fixed = !!open->file_slot;
int ret;
ret = build_open_flags(&open->how, &op);
if (ret)
goto err;
nonblock_set = op.open_flag & O_NONBLOCK;
resolve_nonblock = open->how.resolve & RESOLVE_CACHED;
if (issue_flags & IO_URING_F_NONBLOCK) {
/*
* Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
* it'll always -EAGAIN
*/
if (open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE))
return -EAGAIN;
op.lookup_flags |= LOOKUP_CACHED;
op.open_flag |= O_NONBLOCK;
}
if (!fixed) {
ret = __get_unused_fd_flags(open->how.flags, open->nofile);
if (ret < 0)
goto err;
}
file = do_filp_open(open->dfd, open->filename, &op);
if (IS_ERR(file)) {
/*
* We could hang on to this 'fd' on retrying, but seems like
* marginal gain for something that is now known to be a slower
* path. So just put it, and we'll get a new one when we retry.
*/
if (!fixed)
put_unused_fd(ret);
ret = PTR_ERR(file);
/* only retry if RESOLVE_CACHED wasn't already set by application */
if (ret == -EAGAIN &&
(!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)))
return -EAGAIN;
goto err;
}
if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
file->f_flags &= ~O_NONBLOCK;
fsnotify_open(file);
if (!fixed)
fd_install(ret, file);
else
ret = io_fixed_fd_install(req, issue_flags, file,
open->file_slot);
err:
putname(open->filename);
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_openat(struct io_kiocb *req, unsigned int issue_flags)
{
return io_openat2(req, issue_flags);
}
void io_open_cleanup(struct io_kiocb *req)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
if (open->filename)
putname(open->filename);
}
int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
unsigned int offset)
{
int ret;
io_ring_submit_lock(ctx, issue_flags);
ret = io_fixed_fd_remove(ctx, offset);
io_ring_submit_unlock(ctx, issue_flags);
return ret;
}
static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
return __io_close_fixed(req->ctx, issue_flags, close->file_slot - 1);
}
int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
return -EINVAL;
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
close->fd = READ_ONCE(sqe->fd);
close->file_slot = READ_ONCE(sqe->file_index);
if (close->file_slot && close->fd)
return -EINVAL;
return 0;
}
int io_close(struct io_kiocb *req, unsigned int issue_flags)
{
struct files_struct *files = current->files;
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
struct fdtable *fdt;
struct file *file;
int ret = -EBADF;
if (close->file_slot) {
ret = io_close_fixed(req, issue_flags);
goto err;
}
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if (close->fd >= fdt->max_fds) {
spin_unlock(&files->file_lock);
goto err;
}
file = rcu_dereference_protected(fdt->fd[close->fd],
lockdep_is_held(&files->file_lock));
if (!file || io_is_uring_fops(file)) {
spin_unlock(&files->file_lock);
goto err;
}
/* if the file has a flush method, be safe and punt to async */
if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
spin_unlock(&files->file_lock);
return -EAGAIN;
}
file = __close_fd_get_file(close->fd);
spin_unlock(&files->file_lock);
if (!file)
goto err;
/* No ->flush() or already async, safely close from here */
ret = filp_close(file, current->files);
err:
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}