2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2019 Kyle Evans <kevans@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice(s), this list of conditions and the following disclaimer as
11 * the first lines of this file unmodified other than the possible
12 * addition of one or more copyright notices.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice(s), this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
25 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
27 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
28 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/filio.h>
46 #include "libc_private.h"
48 __weak_reference(shm_open, _shm_open);
49 __weak_reference(shm_open, __sys_shm_open);
51 #define MEMFD_NAME_PREFIX "memfd:"
54 shm_open(const char *path, int flags, mode_t mode)
57 return (__sys_shm_open2(path, flags | O_CLOEXEC, mode, 0, NULL));
61 shm_create_largepage(const char *path, int flags, int psind, int alloc_policy,
64 struct shm_largepage_conf slc;
65 int error, fd, saved_errno;
67 fd = __sys_shm_open2(path, flags | O_CREAT, mode, SHM_LARGEPAGE, NULL);
71 memset(&slc, 0, sizeof(slc));
73 slc.alloc_policy = alloc_policy;
74 error = ioctl(fd, FIOSSHMLPGCNF, &slc);
85 * The path argument is passed to the kernel, but the kernel doesn't currently
86 * do anything with it. Linux exposes it in linprocfs for debugging purposes
87 * only, but our kernel currently will not do the same.
90 memfd_create(const char *name, unsigned int flags)
92 char memfd_name[NAME_MAX + 1];
93 size_t namelen, *pgs, pgsize;
94 struct shm_largepage_conf slc;
95 int error, fd, npgs, oflags, pgidx, saved_errno, shmflags;
101 namelen = strlen(name);
102 if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) {
106 if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB |
107 MFD_HUGE_MASK)) != 0) {
111 /* Size specified but no HUGETLB. */
112 if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) {
117 /* We've already validated that we're sufficiently sized. */
118 snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name);
121 if ((flags & MFD_CLOEXEC) != 0)
123 if ((flags & MFD_ALLOW_SEALING) != 0)
124 shmflags |= SHM_ALLOW_SEALING;
125 if ((flags & MFD_HUGETLB) != 0)
126 shmflags |= SHM_LARGEPAGE;
128 shmflags |= SHM_GROW_ON_WRITE;
129 fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name);
130 if (fd == -1 || (flags & MFD_HUGETLB) == 0)
134 npgs = getpagesizes(NULL, 0);
137 pgs = calloc(npgs, sizeof(size_t));
140 error = getpagesizes(pgs, npgs);
143 pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT);
144 for (pgidx = 0; pgidx < npgs; pgidx++) {
145 if (pgsize == pgs[pgidx])
155 memset(&slc, 0, sizeof(slc));
157 slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT;
158 error = ioctl(fd, FIOSSHMLPGCNF, &slc);