sys/compat/cloudabi/cloudabi_fd.c

   1 /*-
   2  * Copyright (c) 2015 Nuxi, https://nuxi.nl/
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  */
  25
  26 #include <sys/cdefs.h>
  27 __FBSDID("$FreeBSD$");
  28
  29 #include <sys/param.h>
  30 #include <sys/capsicum.h>
  31 #include <sys/filedesc.h>
  32 #include <sys/proc.h>
  33 #include <sys/mman.h>
  34 #include <sys/socketvar.h>
  35 #include <sys/syscallsubr.h>
  36 #include <sys/sysproto.h>
  37 #include <sys/systm.h>
  38 #include <sys/unistd.h>
  39 #include <sys/vnode.h>
  40
  41 #include <contrib/cloudabi/cloudabi_types_common.h>
  42
  43 #include <compat/cloudabi/cloudabi_proto.h>
  44 #include <compat/cloudabi/cloudabi_util.h>
  45
  46 /* Translation between CloudABI and Capsicum rights. */
  47 #define RIGHTS_MAPPINGS \
  48         MAPPING(CLOUDABI_RIGHT_FD_DATASYNC, CAP_FSYNC)                  \
  49         MAPPING(CLOUDABI_RIGHT_FD_READ, CAP_READ)                       \
  50         MAPPING(CLOUDABI_RIGHT_FD_SEEK, CAP_SEEK)                       \
  51         MAPPING(CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS, CAP_FCNTL)            \
  52         MAPPING(CLOUDABI_RIGHT_FD_SYNC, CAP_FSYNC)                      \
  53         MAPPING(CLOUDABI_RIGHT_FD_TELL, CAP_SEEK_TELL)                  \
  54         MAPPING(CLOUDABI_RIGHT_FD_WRITE, CAP_WRITE)                     \
  55         MAPPING(CLOUDABI_RIGHT_FILE_ADVISE)                             \
  56         MAPPING(CLOUDABI_RIGHT_FILE_ALLOCATE, CAP_WRITE)                \
  57         MAPPING(CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY, CAP_MKDIRAT)      \
  58         MAPPING(CLOUDABI_RIGHT_FILE_CREATE_FILE, CAP_CREATE)            \
  59         MAPPING(CLOUDABI_RIGHT_FILE_LINK_SOURCE, CAP_LINKAT_SOURCE)     \
  60         MAPPING(CLOUDABI_RIGHT_FILE_LINK_TARGET, CAP_LINKAT_TARGET)     \
  61         MAPPING(CLOUDABI_RIGHT_FILE_OPEN, CAP_LOOKUP)                   \
  62         MAPPING(CLOUDABI_RIGHT_FILE_READDIR, CAP_READ)                  \
  63         MAPPING(CLOUDABI_RIGHT_FILE_READLINK, CAP_LOOKUP)               \
  64         MAPPING(CLOUDABI_RIGHT_FILE_RENAME_SOURCE, CAP_RENAMEAT_SOURCE) \
  65         MAPPING(CLOUDABI_RIGHT_FILE_RENAME_TARGET, CAP_RENAMEAT_TARGET) \
  66         MAPPING(CLOUDABI_RIGHT_FILE_STAT_FGET, CAP_FSTAT)               \
  67         MAPPING(CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE, CAP_FTRUNCATE)      \
  68         MAPPING(CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES, CAP_FUTIMES)       \
  69         MAPPING(CLOUDABI_RIGHT_FILE_STAT_GET, CAP_FSTATAT)              \
  70         MAPPING(CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES, CAP_FUTIMESAT)      \
  71         MAPPING(CLOUDABI_RIGHT_FILE_SYMLINK, CAP_SYMLINKAT)             \
  72         MAPPING(CLOUDABI_RIGHT_FILE_UNLINK, CAP_UNLINKAT)               \
  73         MAPPING(CLOUDABI_RIGHT_MEM_MAP, CAP_MMAP)                       \
  74         MAPPING(CLOUDABI_RIGHT_MEM_MAP_EXEC, CAP_MMAP_X)                \
  75         MAPPING(CLOUDABI_RIGHT_POLL_FD_READWRITE, CAP_EVENT)            \
  76         MAPPING(CLOUDABI_RIGHT_POLL_PROC_TERMINATE, CAP_EVENT)          \
  77         MAPPING(CLOUDABI_RIGHT_PROC_EXEC, CAP_FEXECVE)                  \
  78         MAPPING(CLOUDABI_RIGHT_SOCK_SHUTDOWN, CAP_SHUTDOWN)             \
  79
  80 int
  81 cloudabi_sys_fd_close(struct thread *td, struct cloudabi_sys_fd_close_args *uap)
  82 {
  83
  84         return (kern_close(td, uap->fd));
  85 }
  86
  87 int
  88 cloudabi_sys_fd_create1(struct thread *td,
  89     struct cloudabi_sys_fd_create1_args *uap)
  90 {
  91         struct filecaps fcaps = {};
  92
  93         switch (uap->type) {
  94         case CLOUDABI_FILETYPE_SHARED_MEMORY:
  95                 cap_rights_init(&fcaps.fc_rights, CAP_FSTAT, CAP_FTRUNCATE,
  96                     CAP_MMAP_RWX);
  97                 return (kern_shm_open(td, SHM_ANON, O_RDWR, 0, &fcaps));
  98         default:
  99                 return (EINVAL);
 100         }
 101 }
 102
 103 int
 104 cloudabi_sys_fd_create2(struct thread *td,
 105     struct cloudabi_sys_fd_create2_args *uap)
 106 {
 107         int fds[2];
 108         int error, type;
 109
 110         switch (uap->type) {
 111         case CLOUDABI_FILETYPE_SOCKET_DGRAM:
 112                 type = SOCK_DGRAM;
 113                 break;
 114         case CLOUDABI_FILETYPE_SOCKET_STREAM:
 115                 type = SOCK_STREAM;
 116                 break;
 117         default:
 118                 return (EINVAL);
 119         }
 120
 121         error = kern_socketpair(td, AF_UNIX, type, 0, fds);
 122         if (error == 0) {
 123                 td->td_retval[0] = fds[0];
 124                 td->td_retval[1] = fds[1];
 125         }
 126         return (0);
 127 }
 128
 129 int
 130 cloudabi_sys_fd_datasync(struct thread *td,
 131     struct cloudabi_sys_fd_datasync_args *uap)
 132 {
 133
 134         return (kern_fsync(td, uap->fd, false));
 135 }
 136
 137 int
 138 cloudabi_sys_fd_dup(struct thread *td, struct cloudabi_sys_fd_dup_args *uap)
 139 {
 140
 141         return (kern_dup(td, FDDUP_NORMAL, 0, uap->from, 0));
 142 }
 143
 144 int
 145 cloudabi_sys_fd_replace(struct thread *td,
 146     struct cloudabi_sys_fd_replace_args *uap)
 147 {
 148         int error;
 149
 150         /*
 151          * CloudABI's equivalent to dup2(). CloudABI processes should
 152          * not depend on hardcoded file descriptor layouts, but simply
 153          * use the file descriptor numbers that are allocated by the
 154          * kernel. Duplicating file descriptors to arbitrary numbers
 155          * should not be done.
 156          *
 157          * Invoke kern_dup() with FDDUP_MUSTREPLACE, so that we return
 158          * EBADF when duplicating to a nonexistent file descriptor. Also
 159          * clear the return value, as this system call yields no return
 160          * value.
 161          */
 162         error = kern_dup(td, FDDUP_MUSTREPLACE, 0, uap->from, uap->to);
 163         td->td_retval[0] = 0;
 164         return (error);
 165 }
 166
 167 int
 168 cloudabi_sys_fd_seek(struct thread *td, struct cloudabi_sys_fd_seek_args *uap)
 169 {
 170         int whence;
 171
 172         switch (uap->whence) {
 173         case CLOUDABI_WHENCE_CUR:
 174                 whence = SEEK_CUR;
 175                 break;
 176         case CLOUDABI_WHENCE_END:
 177                 whence = SEEK_END;
 178                 break;
 179         case CLOUDABI_WHENCE_SET:
 180                 whence = SEEK_SET;
 181                 break;
 182         default:
 183                 return (EINVAL);
 184         }
 185
 186         return (kern_lseek(td, uap->fd, uap->offset, whence));
 187 }
 188
 189 /* Converts a file descriptor to a CloudABI file descriptor type. */
 190 cloudabi_filetype_t
 191 cloudabi_convert_filetype(const struct file *fp)
 192 {
 193         struct socket *so;
 194         struct vnode *vp;
 195
 196         switch (fp->f_type) {
 197         case DTYPE_FIFO:
 198                 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
 199         case DTYPE_PIPE:
 200                 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
 201         case DTYPE_PROCDESC:
 202                 return (CLOUDABI_FILETYPE_PROCESS);
 203         case DTYPE_SHM:
 204                 return (CLOUDABI_FILETYPE_SHARED_MEMORY);
 205         case DTYPE_SOCKET:
 206                 so = fp->f_data;
 207                 switch (so->so_type) {
 208                 case SOCK_DGRAM:
 209                         return (CLOUDABI_FILETYPE_SOCKET_DGRAM);
 210                 case SOCK_STREAM:
 211                         return (CLOUDABI_FILETYPE_SOCKET_STREAM);
 212                 default:
 213                         return (CLOUDABI_FILETYPE_UNKNOWN);
 214                 }
 215         case DTYPE_VNODE:
 216                 vp = fp->f_vnode;
 217                 switch (vp->v_type) {
 218                 case VBLK:
 219                         return (CLOUDABI_FILETYPE_BLOCK_DEVICE);
 220                 case VCHR:
 221                         return (CLOUDABI_FILETYPE_CHARACTER_DEVICE);
 222                 case VDIR:
 223                         return (CLOUDABI_FILETYPE_DIRECTORY);
 224                 case VFIFO:
 225                         return (CLOUDABI_FILETYPE_SOCKET_STREAM);
 226                 case VLNK:
 227                         return (CLOUDABI_FILETYPE_SYMBOLIC_LINK);
 228                 case VREG:
 229                         return (CLOUDABI_FILETYPE_REGULAR_FILE);
 230                 case VSOCK:
 231                         return (CLOUDABI_FILETYPE_SOCKET_STREAM);
 232                 default:
 233                         return (CLOUDABI_FILETYPE_UNKNOWN);
 234                 }
 235         default:
 236                 return (CLOUDABI_FILETYPE_UNKNOWN);
 237         }
 238 }
 239
 240 /* Removes rights that conflict with the file descriptor type. */
 241 void
 242 cloudabi_remove_conflicting_rights(cloudabi_filetype_t filetype,
 243     cloudabi_rights_t *base, cloudabi_rights_t *inheriting)
 244 {
 245
 246         /*
 247          * CloudABI has a small number of additional rights bits to
 248          * disambiguate between multiple purposes. Remove the bits that
 249          * don't apply to the type of the file descriptor.
 250          *
 251          * As file descriptor access modes (O_ACCMODE) has been fully
 252          * replaced by rights bits, CloudABI distinguishes between
 253          * rights that apply to the file descriptor itself (base) versus
 254          * rights of new file descriptors derived from them
 255          * (inheriting). The code below approximates the pair by
 256          * decomposing depending on the file descriptor type.
 257          *
 258          * We need to be somewhat accurate about which actions can
 259          * actually be performed on the file descriptor, as functions
 260          * like fcntl(fd, F_GETFL) are emulated on top of this.
 261          */
 262         switch (filetype) {
 263         case CLOUDABI_FILETYPE_DIRECTORY:
 264                 *base &= CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
 265                     CLOUDABI_RIGHT_FD_SYNC | CLOUDABI_RIGHT_FILE_ADVISE |
 266                     CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY |
 267                     CLOUDABI_RIGHT_FILE_CREATE_FILE |
 268                     CLOUDABI_RIGHT_FILE_LINK_SOURCE |
 269                     CLOUDABI_RIGHT_FILE_LINK_TARGET |
 270                     CLOUDABI_RIGHT_FILE_OPEN |
 271                     CLOUDABI_RIGHT_FILE_READDIR |
 272                     CLOUDABI_RIGHT_FILE_READLINK |
 273                     CLOUDABI_RIGHT_FILE_RENAME_SOURCE |
 274                     CLOUDABI_RIGHT_FILE_RENAME_TARGET |
 275                     CLOUDABI_RIGHT_FILE_STAT_FGET |
 276                     CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
 277                     CLOUDABI_RIGHT_FILE_STAT_GET |
 278                     CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES |
 279                     CLOUDABI_RIGHT_FILE_SYMLINK |
 280                     CLOUDABI_RIGHT_FILE_UNLINK |
 281                     CLOUDABI_RIGHT_POLL_FD_READWRITE;
 282                 *inheriting &= CLOUDABI_RIGHT_FD_DATASYNC |
 283                     CLOUDABI_RIGHT_FD_READ |
 284                     CLOUDABI_RIGHT_FD_SEEK |
 285                     CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
 286                     CLOUDABI_RIGHT_FD_SYNC |
 287                     CLOUDABI_RIGHT_FD_TELL |
 288                     CLOUDABI_RIGHT_FD_WRITE |
 289                     CLOUDABI_RIGHT_FILE_ADVISE |
 290                     CLOUDABI_RIGHT_FILE_ALLOCATE |
 291                     CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY |
 292                     CLOUDABI_RIGHT_FILE_CREATE_FILE |
 293                     CLOUDABI_RIGHT_FILE_LINK_SOURCE |
 294                     CLOUDABI_RIGHT_FILE_LINK_TARGET |
 295                     CLOUDABI_RIGHT_FILE_OPEN |
 296                     CLOUDABI_RIGHT_FILE_READDIR |
 297                     CLOUDABI_RIGHT_FILE_READLINK |
 298                     CLOUDABI_RIGHT_FILE_RENAME_SOURCE |
 299                     CLOUDABI_RIGHT_FILE_RENAME_TARGET |
 300                     CLOUDABI_RIGHT_FILE_STAT_FGET |
 301                     CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE |
 302                     CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
 303                     CLOUDABI_RIGHT_FILE_STAT_GET |
 304                     CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES |
 305                     CLOUDABI_RIGHT_FILE_SYMLINK |
 306                     CLOUDABI_RIGHT_FILE_UNLINK |
 307                     CLOUDABI_RIGHT_MEM_MAP |
 308                     CLOUDABI_RIGHT_MEM_MAP_EXEC |
 309                     CLOUDABI_RIGHT_POLL_FD_READWRITE |
 310                     CLOUDABI_RIGHT_PROC_EXEC;
 311                 break;
 312         case CLOUDABI_FILETYPE_PROCESS:
 313                 *base &= ~(CLOUDABI_RIGHT_FILE_ADVISE |
 314                     CLOUDABI_RIGHT_POLL_FD_READWRITE);
 315                 *inheriting = 0;
 316                 break;
 317         case CLOUDABI_FILETYPE_REGULAR_FILE:
 318                 *base &= CLOUDABI_RIGHT_FD_DATASYNC |
 319                     CLOUDABI_RIGHT_FD_READ |
 320                     CLOUDABI_RIGHT_FD_SEEK |
 321                     CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
 322                     CLOUDABI_RIGHT_FD_SYNC |
 323                     CLOUDABI_RIGHT_FD_TELL |
 324                     CLOUDABI_RIGHT_FD_WRITE |
 325                     CLOUDABI_RIGHT_FILE_ADVISE |
 326                     CLOUDABI_RIGHT_FILE_ALLOCATE |
 327                     CLOUDABI_RIGHT_FILE_STAT_FGET |
 328                     CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE |
 329                     CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
 330                     CLOUDABI_RIGHT_MEM_MAP |
 331                     CLOUDABI_RIGHT_MEM_MAP_EXEC |
 332                     CLOUDABI_RIGHT_POLL_FD_READWRITE |
 333                     CLOUDABI_RIGHT_PROC_EXEC;
 334                 *inheriting = 0;
 335                 break;
 336         case CLOUDABI_FILETYPE_SHARED_MEMORY:
 337                 *base &= ~(CLOUDABI_RIGHT_FD_SEEK |
 338                     CLOUDABI_RIGHT_FD_TELL |
 339                     CLOUDABI_RIGHT_FILE_ADVISE |
 340                     CLOUDABI_RIGHT_FILE_ALLOCATE |
 341                     CLOUDABI_RIGHT_FILE_READDIR);
 342                 *inheriting = 0;
 343                 break;
 344         case CLOUDABI_FILETYPE_SOCKET_DGRAM:
 345         case CLOUDABI_FILETYPE_SOCKET_STREAM:
 346                 *base &= CLOUDABI_RIGHT_FD_READ |
 347                     CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
 348                     CLOUDABI_RIGHT_FD_WRITE |
 349                     CLOUDABI_RIGHT_FILE_STAT_FGET |
 350                     CLOUDABI_RIGHT_POLL_FD_READWRITE |
 351                     CLOUDABI_RIGHT_SOCK_SHUTDOWN;
 352                 break;
 353         default:
 354                 *inheriting = 0;
 355                 break;
 356         }
 357 }
 358
 359 /* Converts FreeBSD's Capsicum rights to CloudABI's set of rights. */
 360 static void
 361 convert_capabilities(const cap_rights_t *capabilities,
 362     cloudabi_filetype_t filetype, cloudabi_rights_t *base,
 363     cloudabi_rights_t *inheriting)
 364 {
 365         cloudabi_rights_t rights;
 366
 367         /* Convert FreeBSD bits to CloudABI bits. */
 368         rights = 0;
 369 #define MAPPING(cloudabi, ...) do {                             \
 370         if (cap_rights_is_set(capabilities, ##__VA_ARGS__))     \
 371                 rights |= (cloudabi);                           \
 372 } while (0);
 373         RIGHTS_MAPPINGS
 374 #undef MAPPING
 375
 376         *base = rights;
 377         *inheriting = rights;
 378         cloudabi_remove_conflicting_rights(filetype, base, inheriting);
 379 }
 380
 381 int
 382 cloudabi_sys_fd_stat_get(struct thread *td,
 383     struct cloudabi_sys_fd_stat_get_args *uap)
 384 {
 385         cloudabi_fdstat_t fsb = {0};
 386         struct file *fp;
 387         cap_rights_t rights;
 388         struct filecaps fcaps;
 389         int error, oflags;
 390
 391         /* Obtain file descriptor properties. */
 392         error = fget_cap(td, uap->fd, cap_rights_init(&rights), &fp,
 393             &fcaps);
 394         if (error != 0)
 395                 return (error);
 396         oflags = OFLAGS(fp->f_flag);
 397         fsb.fs_filetype = cloudabi_convert_filetype(fp);
 398         fdrop(fp, td);
 399
 400         /* Convert file descriptor flags. */
 401         if (oflags & O_APPEND)
 402                 fsb.fs_flags |= CLOUDABI_FDFLAG_APPEND;
 403         if (oflags & O_NONBLOCK)
 404                 fsb.fs_flags |= CLOUDABI_FDFLAG_NONBLOCK;
 405         if (oflags & O_SYNC)
 406                 fsb.fs_flags |= CLOUDABI_FDFLAG_SYNC;
 407
 408         /* Convert capabilities to CloudABI rights. */
 409         convert_capabilities(&fcaps.fc_rights, fsb.fs_filetype,
 410             &fsb.fs_rights_base, &fsb.fs_rights_inheriting);
 411         filecaps_free(&fcaps);
 412         return (copyout(&fsb, (void *)uap->buf, sizeof(fsb)));
 413 }
 414
 415 /* Converts CloudABI rights to a set of Capsicum capabilities. */
 416 int
 417 cloudabi_convert_rights(cloudabi_rights_t in, cap_rights_t *out)
 418 {
 419
 420         cap_rights_init(out);
 421 #define MAPPING(cloudabi, ...) do {                     \
 422         if (in & (cloudabi)) {                          \
 423                 cap_rights_set(out, ##__VA_ARGS__);     \
 424                 in &= ~(cloudabi);                      \
 425         }                                               \
 426 } while (0);
 427         RIGHTS_MAPPINGS
 428 #undef MAPPING
 429         if (in != 0)
 430                 return (ENOTCAPABLE);
 431         return (0);
 432 }
 433
 434 int
 435 cloudabi_sys_fd_stat_put(struct thread *td,
 436     struct cloudabi_sys_fd_stat_put_args *uap)
 437 {
 438         cloudabi_fdstat_t fsb;
 439         cap_rights_t rights;
 440         int error, oflags;
 441
 442         error = copyin(uap->buf, &fsb, sizeof(fsb));
 443         if (error != 0)
 444                 return (error);
 445
 446         if (uap->flags == CLOUDABI_FDSTAT_FLAGS) {
 447                 /* Convert flags. */
 448                 oflags = 0;
 449                 if (fsb.fs_flags & CLOUDABI_FDFLAG_APPEND)
 450                         oflags |= O_APPEND;
 451                 if (fsb.fs_flags & CLOUDABI_FDFLAG_NONBLOCK)
 452                         oflags |= O_NONBLOCK;
 453                 if (fsb.fs_flags & (CLOUDABI_FDFLAG_SYNC |
 454                     CLOUDABI_FDFLAG_DSYNC | CLOUDABI_FDFLAG_RSYNC))
 455                         oflags |= O_SYNC;
 456                 return (kern_fcntl(td, uap->fd, F_SETFL, oflags));
 457         } else if (uap->flags == CLOUDABI_FDSTAT_RIGHTS) {
 458                 /* Convert rights. */
 459                 error = cloudabi_convert_rights(
 460                     fsb.fs_rights_base | fsb.fs_rights_inheriting, &rights);
 461                 if (error != 0)
 462                         return (error);
 463                 return (kern_cap_rights_limit(td, uap->fd, &rights));
 464         }
 465         return (EINVAL);
 466 }
 467
 468 int
 469 cloudabi_sys_fd_sync(struct thread *td, struct cloudabi_sys_fd_sync_args *uap)
 470 {
 471
 472         return (kern_fsync(td, uap->fd, true));
 473 }