io_uring/openclose.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kernel.h>
   3 #include <linux/errno.h>
   4 #include <linux/fs.h>
   5 #include <linux/file.h>
   6 #include <linux/fdtable.h>
   7 #include <linux/fsnotify.h>
   8 #include <linux/namei.h>
   9 #include <linux/io_uring.h>
  10
  11 #include <uapi/linux/io_uring.h>
  12
  13 #include "../fs/internal.h"
  14
  15 #include "io_uring.h"
  16 #include "rsrc.h"
  17 #include "openclose.h"
  18
  19 struct io_open {
  20         struct file                     *file;
  21         int                             dfd;
  22         u32                             file_slot;
  23         struct filename                 *filename;
  24         struct open_how                 how;
  25         unsigned long                   nofile;
  26 };
  27
  28 struct io_close {
  29         struct file                     *file;
  30         int                             fd;
  31         u32                             file_slot;
  32 };
  33
  34 static bool io_openat_force_async(struct io_open *open)
  35 {
  36         /*
  37          * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
  38          * it'll always -EAGAIN
  39          */
  40         return open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE);
  41 }
  42
  43 static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  44 {
  45         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  46         const char __user *fname;
  47         int ret;
  48
  49         if (unlikely(sqe->buf_index))
  50                 return -EINVAL;
  51         if (unlikely(req->flags & REQ_F_FIXED_FILE))
  52                 return -EBADF;
  53
  54         /* open.how should be already initialised */
  55         if (!(open->how.flags & O_PATH) && force_o_largefile())
  56                 open->how.flags |= O_LARGEFILE;
  57
  58         open->dfd = READ_ONCE(sqe->fd);
  59         fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
  60         open->filename = getname(fname);
  61         if (IS_ERR(open->filename)) {
  62                 ret = PTR_ERR(open->filename);
  63                 open->filename = NULL;
  64                 return ret;
  65         }
  66
  67         open->file_slot = READ_ONCE(sqe->file_index);
  68         if (open->file_slot && (open->how.flags & O_CLOEXEC))
  69                 return -EINVAL;
  70
  71         open->nofile = rlimit(RLIMIT_NOFILE);
  72         req->flags |= REQ_F_NEED_CLEANUP;
  73         if (io_openat_force_async(open))
  74                 req->flags |= REQ_F_FORCE_ASYNC;
  75         return 0;
  76 }
  77
  78 int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  79 {
  80         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  81         u64 mode = READ_ONCE(sqe->len);
  82         u64 flags = READ_ONCE(sqe->open_flags);
  83
  84         open->how = build_open_how(flags, mode);
  85         return __io_openat_prep(req, sqe);
  86 }
  87
  88 int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  89 {
  90         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  91         struct open_how __user *how;
  92         size_t len;
  93         int ret;
  94
  95         how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
  96         len = READ_ONCE(sqe->len);
  97         if (len < OPEN_HOW_SIZE_VER0)
  98                 return -EINVAL;
  99
 100         ret = copy_struct_from_user(&open->how, sizeof(open->how), how, len);
 101         if (ret)
 102                 return ret;
 103
 104         return __io_openat_prep(req, sqe);
 105 }
 106
 107 int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
 108 {
 109         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
 110         struct open_flags op;
 111         struct file *file;
 112         bool resolve_nonblock, nonblock_set;
 113         bool fixed = !!open->file_slot;
 114         int ret;
 115
 116         ret = build_open_flags(&open->how, &op);
 117         if (ret)
 118                 goto err;
 119         nonblock_set = op.open_flag & O_NONBLOCK;
 120         resolve_nonblock = open->how.resolve & RESOLVE_CACHED;
 121         if (issue_flags & IO_URING_F_NONBLOCK) {
 122                 WARN_ON_ONCE(io_openat_force_async(open));
 123                 op.lookup_flags |= LOOKUP_CACHED;
 124                 op.open_flag |= O_NONBLOCK;
 125         }
 126
 127         if (!fixed) {
 128                 ret = __get_unused_fd_flags(open->how.flags, open->nofile);
 129                 if (ret < 0)
 130                         goto err;
 131         }
 132
 133         file = do_filp_open(open->dfd, open->filename, &op);
 134         if (IS_ERR(file)) {
 135                 /*
 136                  * We could hang on to this 'fd' on retrying, but seems like
 137                  * marginal gain for something that is now known to be a slower
 138                  * path. So just put it, and we'll get a new one when we retry.
 139                  */
 140                 if (!fixed)
 141                         put_unused_fd(ret);
 142
 143                 ret = PTR_ERR(file);
 144                 /* only retry if RESOLVE_CACHED wasn't already set by application */
 145                 if (ret == -EAGAIN &&
 146                     (!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)))
 147                         return -EAGAIN;
 148                 goto err;
 149         }
 150
 151         if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
 152                 file->f_flags &= ~O_NONBLOCK;
 153
 154         if (!fixed)
 155                 fd_install(ret, file);
 156         else
 157                 ret = io_fixed_fd_install(req, issue_flags, file,
 158                                                 open->file_slot);
 159 err:
 160         putname(open->filename);
 161         req->flags &= ~REQ_F_NEED_CLEANUP;
 162         if (ret < 0)
 163                 req_set_fail(req);
 164         io_req_set_res(req, ret, 0);
 165         return IOU_OK;
 166 }
 167
 168 int io_openat(struct io_kiocb *req, unsigned int issue_flags)
 169 {
 170         return io_openat2(req, issue_flags);
 171 }
 172
 173 void io_open_cleanup(struct io_kiocb *req)
 174 {
 175         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
 176
 177         if (open->filename)
 178                 putname(open->filename);
 179 }
 180
 181 int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
 182                      unsigned int offset)
 183 {
 184         int ret;
 185
 186         io_ring_submit_lock(ctx, issue_flags);
 187         ret = io_fixed_fd_remove(ctx, offset);
 188         io_ring_submit_unlock(ctx, issue_flags);
 189
 190         return ret;
 191 }
 192
 193 static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
 194 {
 195         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 196
 197         return __io_close_fixed(req->ctx, issue_flags, close->file_slot - 1);
 198 }
 199
 200 int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 201 {
 202         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 203
 204         if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
 205                 return -EINVAL;
 206         if (req->flags & REQ_F_FIXED_FILE)
 207                 return -EBADF;
 208
 209         close->fd = READ_ONCE(sqe->fd);
 210         close->file_slot = READ_ONCE(sqe->file_index);
 211         if (close->file_slot && close->fd)
 212                 return -EINVAL;
 213
 214         return 0;
 215 }
 216
 217 int io_close(struct io_kiocb *req, unsigned int issue_flags)
 218 {
 219         struct files_struct *files = current->files;
 220         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 221         struct fdtable *fdt;
 222         struct file *file;
 223         int ret = -EBADF;
 224
 225         if (close->file_slot) {
 226                 ret = io_close_fixed(req, issue_flags);
 227                 goto err;
 228         }
 229
 230         spin_lock(&files->file_lock);
 231         fdt = files_fdtable(files);
 232         if (close->fd >= fdt->max_fds) {
 233                 spin_unlock(&files->file_lock);
 234                 goto err;
 235         }
 236         file = rcu_dereference_protected(fdt->fd[close->fd],
 237                         lockdep_is_held(&files->file_lock));
 238         if (!file || io_is_uring_fops(file)) {
 239                 spin_unlock(&files->file_lock);
 240                 goto err;
 241         }
 242
 243         /* if the file has a flush method, be safe and punt to async */
 244         if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
 245                 spin_unlock(&files->file_lock);
 246                 return -EAGAIN;
 247         }
 248
 249         file = __close_fd_get_file(close->fd);
 250         spin_unlock(&files->file_lock);
 251         if (!file)
 252                 goto err;
 253
 254         /* No ->flush() or already async, safely close from here */
 255         ret = filp_close(file, current->files);
 256 err:
 257         if (ret < 0)
 258                 req_set_fail(req);
 259         io_req_set_res(req, ret, 0);
 260         return IOU_OK;
 261 }