1 /*
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2019 Kyle Evans <[email protected]>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
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
16 * distribution.
17 *
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.
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/filio.h>
36 #include <sys/mman.h>
37
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <limits.h>
41 #include <stdlib.h>
42 #include <stdio.h>
43 #include <string.h>
44 #include <unistd.h>
45
46 #include "libc_private.h"
47
48 __weak_reference(shm_open, _shm_open);
49 __weak_reference(shm_open, __sys_shm_open);
50
51 #define MEMFD_NAME_PREFIX "memfd:"
52
53 int
shm_open(const char * path,int flags,mode_t mode)54 shm_open(const char *path, int flags, mode_t mode)
55 {
56
57 return (__sys_shm_open2(path, flags | O_CLOEXEC, mode, 0, NULL));
58 }
59
60 int
shm_create_largepage(const char * path,int flags,int psind,int alloc_policy,mode_t mode)61 shm_create_largepage(const char *path, int flags, int psind, int alloc_policy,
62 mode_t mode)
63 {
64 struct shm_largepage_conf slc;
65 int error, fd, saved_errno;
66
67 fd = __sys_shm_open2(path, flags | O_CREAT, mode, SHM_LARGEPAGE, NULL);
68 if (fd == -1)
69 return (-1);
70
71 memset(&slc, 0, sizeof(slc));
72 slc.psind = psind;
73 slc.alloc_policy = alloc_policy;
74 error = ioctl(fd, FIOSSHMLPGCNF, &slc);
75 if (error == -1) {
76 saved_errno = errno;
77 close(fd);
78 errno = saved_errno;
79 return (-1);
80 }
81 return (fd);
82 }
83
84 /*
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.
88 */
89 int
memfd_create(const char * name,unsigned int flags)90 memfd_create(const char *name, unsigned int flags)
91 {
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;
96
97 if (name == NULL) {
98 errno = EBADF;
99 return (-1);
100 }
101 namelen = strlen(name);
102 if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) {
103 errno = EINVAL;
104 return (-1);
105 }
106 if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB |
107 MFD_HUGE_MASK)) != 0) {
108 errno = EINVAL;
109 return (-1);
110 }
111 /* Size specified but no HUGETLB. */
112 if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) {
113 errno = EINVAL;
114 return (-1);
115 }
116
117 /* We've already validated that we're sufficiently sized. */
118 snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name);
119 oflags = O_RDWR;
120 shmflags = 0;
121 if ((flags & MFD_CLOEXEC) != 0)
122 oflags |= O_CLOEXEC;
123 if ((flags & MFD_ALLOW_SEALING) != 0)
124 shmflags |= SHM_ALLOW_SEALING;
125 if ((flags & MFD_HUGETLB) != 0)
126 shmflags |= SHM_LARGEPAGE;
127 else
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)
131 return (fd);
132
133 pgs = NULL;
134 npgs = getpagesizes(NULL, 0);
135 if (npgs == -1)
136 goto clean;
137 pgs = calloc(npgs, sizeof(size_t));
138 if (pgs == NULL)
139 goto clean;
140 error = getpagesizes(pgs, npgs);
141 if (error == -1)
142 goto clean;
143 pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT);
144 for (pgidx = 0; pgidx < npgs; pgidx++) {
145 if (pgsize == pgs[pgidx])
146 break;
147 }
148 if (pgidx == npgs) {
149 errno = EOPNOTSUPP;
150 goto clean;
151 }
152 free(pgs);
153 pgs = NULL;
154
155 memset(&slc, 0, sizeof(slc));
156 slc.psind = pgidx;
157 slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT;
158 error = ioctl(fd, FIOSSHMLPGCNF, &slc);
159 if (error == -1)
160 goto clean;
161 return (fd);
162
163 clean:
164 saved_errno = errno;
165 close(fd);
166 free(pgs);
167 errno = saved_errno;
168 return (-1);
169 }
170