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/fcntl.h>
32 #include <sys/filedesc.h>
33 #include <sys/proc.h>
34 #include <sys/mman.h>
35 #include <sys/socketvar.h>
36 #include <sys/syscallsubr.h>
37 #include <sys/sysproto.h>
38 #include <sys/systm.h>
39 #include <sys/unistd.h>
40 #include <sys/vnode.h>
41
42 #include <contrib/cloudabi/cloudabi_types_common.h>
43
44 #include <compat/cloudabi/cloudabi_proto.h>
45 #include <compat/cloudabi/cloudabi_util.h>
46
47 /* Translation between CloudABI and Capsicum rights. */
48 #define RIGHTS_MAPPINGS \
49 MAPPING(CLOUDABI_RIGHT_FD_DATASYNC, CAP_FSYNC) \
50 MAPPING(CLOUDABI_RIGHT_FD_READ, CAP_READ) \
51 MAPPING(CLOUDABI_RIGHT_FD_SEEK, CAP_SEEK) \
52 MAPPING(CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS, CAP_FCNTL) \
53 MAPPING(CLOUDABI_RIGHT_FD_SYNC, CAP_FSYNC) \
54 MAPPING(CLOUDABI_RIGHT_FD_TELL, CAP_SEEK_TELL) \
55 MAPPING(CLOUDABI_RIGHT_FD_WRITE, CAP_WRITE) \
56 MAPPING(CLOUDABI_RIGHT_FILE_ADVISE) \
57 MAPPING(CLOUDABI_RIGHT_FILE_ALLOCATE, CAP_WRITE) \
58 MAPPING(CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY, CAP_MKDIRAT) \
59 MAPPING(CLOUDABI_RIGHT_FILE_CREATE_FILE, CAP_CREATE) \
60 MAPPING(CLOUDABI_RIGHT_FILE_LINK_SOURCE, CAP_LINKAT_SOURCE) \
61 MAPPING(CLOUDABI_RIGHT_FILE_LINK_TARGET, CAP_LINKAT_TARGET) \
62 MAPPING(CLOUDABI_RIGHT_FILE_OPEN, CAP_LOOKUP) \
63 MAPPING(CLOUDABI_RIGHT_FILE_READDIR, CAP_READ) \
64 MAPPING(CLOUDABI_RIGHT_FILE_READLINK, CAP_LOOKUP) \
65 MAPPING(CLOUDABI_RIGHT_FILE_RENAME_SOURCE, CAP_RENAMEAT_SOURCE) \
66 MAPPING(CLOUDABI_RIGHT_FILE_RENAME_TARGET, CAP_RENAMEAT_TARGET) \
67 MAPPING(CLOUDABI_RIGHT_FILE_STAT_FGET, CAP_FSTAT) \
68 MAPPING(CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE, CAP_FTRUNCATE) \
69 MAPPING(CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES, CAP_FUTIMES) \
70 MAPPING(CLOUDABI_RIGHT_FILE_STAT_GET, CAP_FSTATAT) \
71 MAPPING(CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES, CAP_FUTIMESAT) \
72 MAPPING(CLOUDABI_RIGHT_FILE_SYMLINK, CAP_SYMLINKAT) \
73 MAPPING(CLOUDABI_RIGHT_FILE_UNLINK, CAP_UNLINKAT) \
74 MAPPING(CLOUDABI_RIGHT_MEM_MAP, CAP_MMAP) \
75 MAPPING(CLOUDABI_RIGHT_MEM_MAP_EXEC, CAP_MMAP_X) \
76 MAPPING(CLOUDABI_RIGHT_POLL_FD_READWRITE, CAP_EVENT) \
77 MAPPING(CLOUDABI_RIGHT_POLL_PROC_TERMINATE, CAP_EVENT) \
78 MAPPING(CLOUDABI_RIGHT_PROC_EXEC, CAP_FEXECVE) \
79 MAPPING(CLOUDABI_RIGHT_SOCK_SHUTDOWN, CAP_SHUTDOWN) \
80
81 int
cloudabi_sys_fd_close(struct thread * td,struct cloudabi_sys_fd_close_args * uap)82 cloudabi_sys_fd_close(struct thread *td, struct cloudabi_sys_fd_close_args *uap)
83 {
84
85 return (kern_close(td, uap->fd));
86 }
87
88 int
cloudabi_sys_fd_create1(struct thread * td,struct cloudabi_sys_fd_create1_args * uap)89 cloudabi_sys_fd_create1(struct thread *td,
90 struct cloudabi_sys_fd_create1_args *uap)
91 {
92 struct filecaps fcaps = {};
93
94 switch (uap->type) {
95 case CLOUDABI_FILETYPE_SHARED_MEMORY:
96 cap_rights_init(&fcaps.fc_rights, CAP_FSTAT, CAP_FTRUNCATE,
97 CAP_MMAP_RWX);
98 return (kern_shm_open(td, SHM_ANON, O_RDWR | O_CLOEXEC, 0,
99 &fcaps));
100 default:
101 return (EINVAL);
102 }
103 }
104
105 int
cloudabi_sys_fd_create2(struct thread * td,struct cloudabi_sys_fd_create2_args * uap)106 cloudabi_sys_fd_create2(struct thread *td,
107 struct cloudabi_sys_fd_create2_args *uap)
108 {
109 int fds[2];
110 int error, type;
111
112 switch (uap->type) {
113 case CLOUDABI_FILETYPE_SOCKET_DGRAM:
114 type = SOCK_DGRAM;
115 break;
116 case CLOUDABI_FILETYPE_SOCKET_STREAM:
117 type = SOCK_STREAM;
118 break;
119 default:
120 return (EINVAL);
121 }
122
123 error = kern_socketpair(td, AF_UNIX, type, 0, fds);
124 if (error == 0) {
125 td->td_retval[0] = fds[0];
126 td->td_retval[1] = fds[1];
127 }
128 return (0);
129 }
130
131 int
cloudabi_sys_fd_datasync(struct thread * td,struct cloudabi_sys_fd_datasync_args * uap)132 cloudabi_sys_fd_datasync(struct thread *td,
133 struct cloudabi_sys_fd_datasync_args *uap)
134 {
135
136 return (kern_fsync(td, uap->fd, false));
137 }
138
139 int
cloudabi_sys_fd_dup(struct thread * td,struct cloudabi_sys_fd_dup_args * uap)140 cloudabi_sys_fd_dup(struct thread *td, struct cloudabi_sys_fd_dup_args *uap)
141 {
142
143 return (kern_dup(td, FDDUP_NORMAL, 0, uap->from, 0));
144 }
145
146 int
cloudabi_sys_fd_replace(struct thread * td,struct cloudabi_sys_fd_replace_args * uap)147 cloudabi_sys_fd_replace(struct thread *td,
148 struct cloudabi_sys_fd_replace_args *uap)
149 {
150 int error;
151
152 /*
153 * CloudABI's equivalent to dup2(). CloudABI processes should
154 * not depend on hardcoded file descriptor layouts, but simply
155 * use the file descriptor numbers that are allocated by the
156 * kernel. Duplicating file descriptors to arbitrary numbers
157 * should not be done.
158 *
159 * Invoke kern_dup() with FDDUP_MUSTREPLACE, so that we return
160 * EBADF when duplicating to a nonexistent file descriptor. Also
161 * clear the return value, as this system call yields no return
162 * value.
163 */
164 error = kern_dup(td, FDDUP_MUSTREPLACE, 0, uap->from, uap->to);
165 td->td_retval[0] = 0;
166 return (error);
167 }
168
169 int
cloudabi_sys_fd_seek(struct thread * td,struct cloudabi_sys_fd_seek_args * uap)170 cloudabi_sys_fd_seek(struct thread *td, struct cloudabi_sys_fd_seek_args *uap)
171 {
172 int whence;
173
174 switch (uap->whence) {
175 case CLOUDABI_WHENCE_CUR:
176 whence = SEEK_CUR;
177 break;
178 case CLOUDABI_WHENCE_END:
179 whence = SEEK_END;
180 break;
181 case CLOUDABI_WHENCE_SET:
182 whence = SEEK_SET;
183 break;
184 default:
185 return (EINVAL);
186 }
187
188 return (kern_lseek(td, uap->fd, uap->offset, whence));
189 }
190
191 /* Converts a file descriptor to a CloudABI file descriptor type. */
192 cloudabi_filetype_t
cloudabi_convert_filetype(const struct file * fp)193 cloudabi_convert_filetype(const struct file *fp)
194 {
195 struct socket *so;
196 struct vnode *vp;
197
198 switch (fp->f_type) {
199 case DTYPE_FIFO:
200 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
201 case DTYPE_PIPE:
202 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
203 case DTYPE_PROCDESC:
204 return (CLOUDABI_FILETYPE_PROCESS);
205 case DTYPE_SHM:
206 return (CLOUDABI_FILETYPE_SHARED_MEMORY);
207 case DTYPE_SOCKET:
208 so = fp->f_data;
209 switch (so->so_type) {
210 case SOCK_DGRAM:
211 return (CLOUDABI_FILETYPE_SOCKET_DGRAM);
212 case SOCK_STREAM:
213 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
214 default:
215 return (CLOUDABI_FILETYPE_UNKNOWN);
216 }
217 case DTYPE_VNODE:
218 vp = fp->f_vnode;
219 switch (vp->v_type) {
220 case VBLK:
221 return (CLOUDABI_FILETYPE_BLOCK_DEVICE);
222 case VCHR:
223 return (CLOUDABI_FILETYPE_CHARACTER_DEVICE);
224 case VDIR:
225 return (CLOUDABI_FILETYPE_DIRECTORY);
226 case VFIFO:
227 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
228 case VLNK:
229 return (CLOUDABI_FILETYPE_SYMBOLIC_LINK);
230 case VREG:
231 return (CLOUDABI_FILETYPE_REGULAR_FILE);
232 case VSOCK:
233 return (CLOUDABI_FILETYPE_SOCKET_STREAM);
234 default:
235 return (CLOUDABI_FILETYPE_UNKNOWN);
236 }
237 default:
238 return (CLOUDABI_FILETYPE_UNKNOWN);
239 }
240 }
241
242 /* Removes rights that conflict with the file descriptor type. */
243 void
cloudabi_remove_conflicting_rights(cloudabi_filetype_t filetype,cloudabi_rights_t * base,cloudabi_rights_t * inheriting)244 cloudabi_remove_conflicting_rights(cloudabi_filetype_t filetype,
245 cloudabi_rights_t *base, cloudabi_rights_t *inheriting)
246 {
247
248 /*
249 * CloudABI has a small number of additional rights bits to
250 * disambiguate between multiple purposes. Remove the bits that
251 * don't apply to the type of the file descriptor.
252 *
253 * As file descriptor access modes (O_ACCMODE) has been fully
254 * replaced by rights bits, CloudABI distinguishes between
255 * rights that apply to the file descriptor itself (base) versus
256 * rights of new file descriptors derived from them
257 * (inheriting). The code below approximates the pair by
258 * decomposing depending on the file descriptor type.
259 *
260 * We need to be somewhat accurate about which actions can
261 * actually be performed on the file descriptor, as functions
262 * like fcntl(fd, F_GETFL) are emulated on top of this.
263 */
264 switch (filetype) {
265 case CLOUDABI_FILETYPE_DIRECTORY:
266 *base &= CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
267 CLOUDABI_RIGHT_FD_SYNC | CLOUDABI_RIGHT_FILE_ADVISE |
268 CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY |
269 CLOUDABI_RIGHT_FILE_CREATE_FILE |
270 CLOUDABI_RIGHT_FILE_LINK_SOURCE |
271 CLOUDABI_RIGHT_FILE_LINK_TARGET |
272 CLOUDABI_RIGHT_FILE_OPEN |
273 CLOUDABI_RIGHT_FILE_READDIR |
274 CLOUDABI_RIGHT_FILE_READLINK |
275 CLOUDABI_RIGHT_FILE_RENAME_SOURCE |
276 CLOUDABI_RIGHT_FILE_RENAME_TARGET |
277 CLOUDABI_RIGHT_FILE_STAT_FGET |
278 CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
279 CLOUDABI_RIGHT_FILE_STAT_GET |
280 CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES |
281 CLOUDABI_RIGHT_FILE_SYMLINK |
282 CLOUDABI_RIGHT_FILE_UNLINK |
283 CLOUDABI_RIGHT_POLL_FD_READWRITE;
284 *inheriting &= CLOUDABI_RIGHT_FD_DATASYNC |
285 CLOUDABI_RIGHT_FD_READ |
286 CLOUDABI_RIGHT_FD_SEEK |
287 CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
288 CLOUDABI_RIGHT_FD_SYNC |
289 CLOUDABI_RIGHT_FD_TELL |
290 CLOUDABI_RIGHT_FD_WRITE |
291 CLOUDABI_RIGHT_FILE_ADVISE |
292 CLOUDABI_RIGHT_FILE_ALLOCATE |
293 CLOUDABI_RIGHT_FILE_CREATE_DIRECTORY |
294 CLOUDABI_RIGHT_FILE_CREATE_FILE |
295 CLOUDABI_RIGHT_FILE_LINK_SOURCE |
296 CLOUDABI_RIGHT_FILE_LINK_TARGET |
297 CLOUDABI_RIGHT_FILE_OPEN |
298 CLOUDABI_RIGHT_FILE_READDIR |
299 CLOUDABI_RIGHT_FILE_READLINK |
300 CLOUDABI_RIGHT_FILE_RENAME_SOURCE |
301 CLOUDABI_RIGHT_FILE_RENAME_TARGET |
302 CLOUDABI_RIGHT_FILE_STAT_FGET |
303 CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE |
304 CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
305 CLOUDABI_RIGHT_FILE_STAT_GET |
306 CLOUDABI_RIGHT_FILE_STAT_PUT_TIMES |
307 CLOUDABI_RIGHT_FILE_SYMLINK |
308 CLOUDABI_RIGHT_FILE_UNLINK |
309 CLOUDABI_RIGHT_MEM_MAP |
310 CLOUDABI_RIGHT_MEM_MAP_EXEC |
311 CLOUDABI_RIGHT_POLL_FD_READWRITE |
312 CLOUDABI_RIGHT_PROC_EXEC;
313 break;
314 case CLOUDABI_FILETYPE_PROCESS:
315 *base &= ~(CLOUDABI_RIGHT_FILE_ADVISE |
316 CLOUDABI_RIGHT_POLL_FD_READWRITE);
317 *inheriting = 0;
318 break;
319 case CLOUDABI_FILETYPE_REGULAR_FILE:
320 *base &= CLOUDABI_RIGHT_FD_DATASYNC |
321 CLOUDABI_RIGHT_FD_READ |
322 CLOUDABI_RIGHT_FD_SEEK |
323 CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
324 CLOUDABI_RIGHT_FD_SYNC |
325 CLOUDABI_RIGHT_FD_TELL |
326 CLOUDABI_RIGHT_FD_WRITE |
327 CLOUDABI_RIGHT_FILE_ADVISE |
328 CLOUDABI_RIGHT_FILE_ALLOCATE |
329 CLOUDABI_RIGHT_FILE_STAT_FGET |
330 CLOUDABI_RIGHT_FILE_STAT_FPUT_SIZE |
331 CLOUDABI_RIGHT_FILE_STAT_FPUT_TIMES |
332 CLOUDABI_RIGHT_MEM_MAP |
333 CLOUDABI_RIGHT_MEM_MAP_EXEC |
334 CLOUDABI_RIGHT_POLL_FD_READWRITE |
335 CLOUDABI_RIGHT_PROC_EXEC;
336 *inheriting = 0;
337 break;
338 case CLOUDABI_FILETYPE_SHARED_MEMORY:
339 *base &= ~(CLOUDABI_RIGHT_FD_SEEK |
340 CLOUDABI_RIGHT_FD_TELL |
341 CLOUDABI_RIGHT_FILE_ADVISE |
342 CLOUDABI_RIGHT_FILE_ALLOCATE |
343 CLOUDABI_RIGHT_FILE_READDIR);
344 *inheriting = 0;
345 break;
346 case CLOUDABI_FILETYPE_SOCKET_DGRAM:
347 case CLOUDABI_FILETYPE_SOCKET_STREAM:
348 *base &= CLOUDABI_RIGHT_FD_READ |
349 CLOUDABI_RIGHT_FD_STAT_PUT_FLAGS |
350 CLOUDABI_RIGHT_FD_WRITE |
351 CLOUDABI_RIGHT_FILE_STAT_FGET |
352 CLOUDABI_RIGHT_POLL_FD_READWRITE |
353 CLOUDABI_RIGHT_SOCK_SHUTDOWN;
354 break;
355 default:
356 *inheriting = 0;
357 break;
358 }
359 }
360
361 /* Converts FreeBSD's Capsicum rights to CloudABI's set of rights. */
362 static void
convert_capabilities(const cap_rights_t * capabilities,cloudabi_filetype_t filetype,cloudabi_rights_t * base,cloudabi_rights_t * inheriting)363 convert_capabilities(const cap_rights_t *capabilities,
364 cloudabi_filetype_t filetype, cloudabi_rights_t *base,
365 cloudabi_rights_t *inheriting)
366 {
367 cloudabi_rights_t rights;
368
369 /* Convert FreeBSD bits to CloudABI bits. */
370 rights = 0;
371 #define MAPPING(cloudabi, ...) do { \
372 if (cap_rights_is_set(capabilities, ##__VA_ARGS__)) \
373 rights |= (cloudabi); \
374 } while (0);
375 RIGHTS_MAPPINGS
376 #undef MAPPING
377
378 *base = rights;
379 *inheriting = rights;
380 cloudabi_remove_conflicting_rights(filetype, base, inheriting);
381 }
382
383 int
cloudabi_sys_fd_stat_get(struct thread * td,struct cloudabi_sys_fd_stat_get_args * uap)384 cloudabi_sys_fd_stat_get(struct thread *td,
385 struct cloudabi_sys_fd_stat_get_args *uap)
386 {
387 cloudabi_fdstat_t fsb = {0};
388 struct file *fp;
389 cap_rights_t rights;
390 struct filecaps fcaps;
391 int error, oflags;
392
393 /* Obtain file descriptor properties. */
394 error = fget_cap(td, uap->fd, cap_rights_init(&rights), &fp,
395 &fcaps);
396 if (error != 0)
397 return (error);
398 oflags = OFLAGS(fp->f_flag);
399 fsb.fs_filetype = cloudabi_convert_filetype(fp);
400 fdrop(fp, td);
401
402 /* Convert file descriptor flags. */
403 if (oflags & O_APPEND)
404 fsb.fs_flags |= CLOUDABI_FDFLAG_APPEND;
405 if (oflags & O_NONBLOCK)
406 fsb.fs_flags |= CLOUDABI_FDFLAG_NONBLOCK;
407 if (oflags & O_SYNC)
408 fsb.fs_flags |= CLOUDABI_FDFLAG_SYNC;
409
410 /* Convert capabilities to CloudABI rights. */
411 convert_capabilities(&fcaps.fc_rights, fsb.fs_filetype,
412 &fsb.fs_rights_base, &fsb.fs_rights_inheriting);
413 filecaps_free(&fcaps);
414 return (copyout(&fsb, (void *)uap->buf, sizeof(fsb)));
415 }
416
417 /* Converts CloudABI rights to a set of Capsicum capabilities. */
418 int
cloudabi_convert_rights(cloudabi_rights_t in,cap_rights_t * out)419 cloudabi_convert_rights(cloudabi_rights_t in, cap_rights_t *out)
420 {
421
422 cap_rights_init(out);
423 #define MAPPING(cloudabi, ...) do { \
424 if (in & (cloudabi)) { \
425 cap_rights_set(out, ##__VA_ARGS__); \
426 in &= ~(cloudabi); \
427 } \
428 } while (0);
429 RIGHTS_MAPPINGS
430 #undef MAPPING
431 if (in != 0)
432 return (ENOTCAPABLE);
433 return (0);
434 }
435
436 int
cloudabi_sys_fd_stat_put(struct thread * td,struct cloudabi_sys_fd_stat_put_args * uap)437 cloudabi_sys_fd_stat_put(struct thread *td,
438 struct cloudabi_sys_fd_stat_put_args *uap)
439 {
440 cloudabi_fdstat_t fsb;
441 cap_rights_t rights;
442 int error, oflags;
443
444 error = copyin(uap->buf, &fsb, sizeof(fsb));
445 if (error != 0)
446 return (error);
447
448 if (uap->flags == CLOUDABI_FDSTAT_FLAGS) {
449 /* Convert flags. */
450 oflags = 0;
451 if (fsb.fs_flags & CLOUDABI_FDFLAG_APPEND)
452 oflags |= O_APPEND;
453 if (fsb.fs_flags & CLOUDABI_FDFLAG_NONBLOCK)
454 oflags |= O_NONBLOCK;
455 if (fsb.fs_flags & (CLOUDABI_FDFLAG_SYNC |
456 CLOUDABI_FDFLAG_DSYNC | CLOUDABI_FDFLAG_RSYNC))
457 oflags |= O_SYNC;
458 return (kern_fcntl(td, uap->fd, F_SETFL, oflags));
459 } else if (uap->flags == CLOUDABI_FDSTAT_RIGHTS) {
460 /* Convert rights. */
461 error = cloudabi_convert_rights(
462 fsb.fs_rights_base | fsb.fs_rights_inheriting, &rights);
463 if (error != 0)
464 return (error);
465 return (kern_cap_rights_limit(td, uap->fd, &rights));
466 }
467 return (EINVAL);
468 }
469
470 int
cloudabi_sys_fd_sync(struct thread * td,struct cloudabi_sys_fd_sync_args * uap)471 cloudabi_sys_fd_sync(struct thread *td, struct cloudabi_sys_fd_sync_args *uap)
472 {
473
474 return (kern_fsync(td, uap->fd, true));
475 }
476