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 struct io_fixed_install {
  35         struct file                     *file;
  36         unsigned int                    o_flags;
  37 };
  38
  39 static bool io_openat_force_async(struct io_open *open)
  40 {
  41         /*
  42          * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
  43          * it'll always -EAGAIN. Note that we test for __O_TMPFILE because
  44          * O_TMPFILE includes O_DIRECTORY, which isn't a flag we need to force
  45          * async for.
  46          */
  47         return open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE);
  48 }
  49
  50 static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  51 {
  52         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  53         const char __user *fname;
  54         int ret;
  55
  56         if (unlikely(sqe->buf_index))
  57                 return -EINVAL;
  58         if (unlikely(req->flags & REQ_F_FIXED_FILE))
  59                 return -EBADF;
  60
  61         /* open.how should be already initialised */
  62         if (!(open->how.flags & O_PATH) && force_o_largefile())
  63                 open->how.flags |= O_LARGEFILE;
  64
  65         open->dfd = READ_ONCE(sqe->fd);
  66         fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
  67         open->filename = getname(fname);
  68         if (IS_ERR(open->filename)) {
  69                 ret = PTR_ERR(open->filename);
  70                 open->filename = NULL;
  71                 return ret;
  72         }
  73
  74         open->file_slot = READ_ONCE(sqe->file_index);
  75         if (open->file_slot && (open->how.flags & O_CLOEXEC))
  76                 return -EINVAL;
  77
  78         open->nofile = rlimit(RLIMIT_NOFILE);
  79         req->flags |= REQ_F_NEED_CLEANUP;
  80         if (io_openat_force_async(open))
  81                 req->flags |= REQ_F_FORCE_ASYNC;
  82         return 0;
  83 }
  84
  85 int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  86 {
  87         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  88         u64 mode = READ_ONCE(sqe->len);
  89         u64 flags = READ_ONCE(sqe->open_flags);
  90
  91         open->how = build_open_how(flags, mode);
  92         return __io_openat_prep(req, sqe);
  93 }
  94
  95 int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
  96 {
  97         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
  98         struct open_how __user *how;
  99         size_t len;
 100         int ret;
 101
 102         how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 103         len = READ_ONCE(sqe->len);
 104         if (len < OPEN_HOW_SIZE_VER0)
 105                 return -EINVAL;
 106
 107         ret = copy_struct_from_user(&open->how, sizeof(open->how), how, len);
 108         if (ret)
 109                 return ret;
 110
 111         return __io_openat_prep(req, sqe);
 112 }
 113
 114 int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
 115 {
 116         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
 117         struct open_flags op;
 118         struct file *file;
 119         bool resolve_nonblock, nonblock_set;
 120         bool fixed = !!open->file_slot;
 121         int ret;
 122
 123         ret = build_open_flags(&open->how, &op);
 124         if (ret)
 125                 goto err;
 126         nonblock_set = op.open_flag & O_NONBLOCK;
 127         resolve_nonblock = open->how.resolve & RESOLVE_CACHED;
 128         if (issue_flags & IO_URING_F_NONBLOCK) {
 129                 WARN_ON_ONCE(io_openat_force_async(open));
 130                 op.lookup_flags |= LOOKUP_CACHED;
 131                 op.open_flag |= O_NONBLOCK;
 132         }
 133
 134         if (!fixed) {
 135                 ret = __get_unused_fd_flags(open->how.flags, open->nofile);
 136                 if (ret < 0)
 137                         goto err;
 138         }
 139
 140         file = do_filp_open(open->dfd, open->filename, &op);
 141         if (IS_ERR(file)) {
 142                 /*
 143                  * We could hang on to this 'fd' on retrying, but seems like
 144                  * marginal gain for something that is now known to be a slower
 145                  * path. So just put it, and we'll get a new one when we retry.
 146                  */
 147                 if (!fixed)
 148                         put_unused_fd(ret);
 149
 150                 ret = PTR_ERR(file);
 151                 /* only retry if RESOLVE_CACHED wasn't already set by application */
 152                 if (ret == -EAGAIN &&
 153                     (!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)))
 154                         return -EAGAIN;
 155                 goto err;
 156         }
 157
 158         if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
 159                 file->f_flags &= ~O_NONBLOCK;
 160
 161         if (!fixed)
 162                 fd_install(ret, file);
 163         else
 164                 ret = io_fixed_fd_install(req, issue_flags, file,
 165                                                 open->file_slot);
 166 err:
 167         putname(open->filename);
 168         req->flags &= ~REQ_F_NEED_CLEANUP;
 169         if (ret < 0)
 170                 req_set_fail(req);
 171         io_req_set_res(req, ret, 0);
 172         return IOU_OK;
 173 }
 174
 175 int io_openat(struct io_kiocb *req, unsigned int issue_flags)
 176 {
 177         return io_openat2(req, issue_flags);
 178 }
 179
 180 void io_open_cleanup(struct io_kiocb *req)
 181 {
 182         struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
 183
 184         if (open->filename)
 185                 putname(open->filename);
 186 }
 187
 188 int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
 189                      unsigned int offset)
 190 {
 191         int ret;
 192
 193         io_ring_submit_lock(ctx, issue_flags);
 194         ret = io_fixed_fd_remove(ctx, offset);
 195         io_ring_submit_unlock(ctx, issue_flags);
 196
 197         return ret;
 198 }
 199
 200 static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
 201 {
 202         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 203
 204         return __io_close_fixed(req->ctx, issue_flags, close->file_slot - 1);
 205 }
 206
 207 int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 208 {
 209         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 210
 211         if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
 212                 return -EINVAL;
 213         if (req->flags & REQ_F_FIXED_FILE)
 214                 return -EBADF;
 215
 216         close->fd = READ_ONCE(sqe->fd);
 217         close->file_slot = READ_ONCE(sqe->file_index);
 218         if (close->file_slot && close->fd)
 219                 return -EINVAL;
 220
 221         return 0;
 222 }
 223
 224 int io_close(struct io_kiocb *req, unsigned int issue_flags)
 225 {
 226         struct files_struct *files = current->files;
 227         struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
 228         struct file *file;
 229         int ret = -EBADF;
 230
 231         if (close->file_slot) {
 232                 ret = io_close_fixed(req, issue_flags);
 233                 goto err;
 234         }
 235
 236         spin_lock(&files->file_lock);
 237         file = files_lookup_fd_locked(files, close->fd);
 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 = file_close_fd_locked(files, 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 }
 262
 263 int io_install_fixed_fd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 264 {
 265         struct io_fixed_install *ifi;
 266         unsigned int flags;
 267
 268         if (sqe->off || sqe->addr || sqe->len || sqe->buf_index ||
 269             sqe->splice_fd_in || sqe->addr3)
 270                 return -EINVAL;
 271
 272         /* must be a fixed file */
 273         if (!(req->flags & REQ_F_FIXED_FILE))
 274                 return -EBADF;
 275
 276         flags = READ_ONCE(sqe->install_fd_flags);
 277         if (flags & ~IORING_FIXED_FD_NO_CLOEXEC)
 278                 return -EINVAL;
 279
 280         /* ensure the task's creds are used when installing/receiving fds */
 281         if (req->flags & REQ_F_CREDS)
 282                 return -EPERM;
 283
 284         /* default to O_CLOEXEC, disable if IORING_FIXED_FD_NO_CLOEXEC is set */
 285         ifi = io_kiocb_to_cmd(req, struct io_fixed_install);
 286         ifi->o_flags = O_CLOEXEC;
 287         if (flags & IORING_FIXED_FD_NO_CLOEXEC)
 288                 ifi->o_flags = 0;
 289
 290         return 0;
 291 }
 292
 293 int io_install_fixed_fd(struct io_kiocb *req, unsigned int issue_flags)
 294 {
 295         struct io_fixed_install *ifi;
 296         int ret;
 297
 298         ifi = io_kiocb_to_cmd(req, struct io_fixed_install);
 299         ret = receive_fd(req->file, NULL, ifi->o_flags);
 300         if (ret < 0)
 301                 req_set_fail(req);
 302         io_req_set_res(req, ret, 0);
 303         return IOU_OK;
 304 }