1 /* 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2019 Kyle Evans <kevans@FreeBSD.org> 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 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 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 (error == -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 #define K(x) ((size_t)(x) * 1024) 85 #define M(x) (K(x) * 1024) 86 #define G(x) (M(x) * 1024) 87 static const struct { 88 int mask; 89 size_t pgsize; 90 } mfd_huge_sizes[] = { 91 { .mask = MFD_HUGE_64KB, .pgsize = K(64) }, 92 { .mask = MFD_HUGE_512KB, .pgsize = K(512) }, 93 { .mask = MFD_HUGE_1MB, .pgsize = M(1) }, 94 { .mask = MFD_HUGE_2MB, .pgsize = M(2) }, 95 { .mask = MFD_HUGE_8MB, .pgsize = M(8) }, 96 { .mask = MFD_HUGE_16MB, .pgsize = M(16) }, 97 { .mask = MFD_HUGE_32MB, .pgsize = M(32) }, 98 { .mask = MFD_HUGE_256MB, .pgsize = M(256) }, 99 { .mask = MFD_HUGE_512MB, .pgsize = M(512) }, 100 { .mask = MFD_HUGE_1GB, .pgsize = G(1) }, 101 { .mask = MFD_HUGE_2GB, .pgsize = G(2) }, 102 { .mask = MFD_HUGE_16GB, .pgsize = G(16) }, 103 }; 104 105 /* 106 * The path argument is passed to the kernel, but the kernel doesn't currently 107 * do anything with it. Linux exposes it in linprocfs for debugging purposes 108 * only, but our kernel currently will not do the same. 109 */ 110 int 111 memfd_create(const char *name, unsigned int flags) 112 { 113 char memfd_name[NAME_MAX + 1]; 114 size_t namelen, *pgs; 115 struct shm_largepage_conf slc; 116 int error, fd, i, npgs, oflags, pgidx, saved_errno, shmflags; 117 118 if (name == NULL) 119 return (EBADF); 120 namelen = strlen(name); 121 if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) 122 return (EINVAL); 123 if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | 124 MFD_HUGE_MASK)) != 0) 125 return (EINVAL); 126 /* Size specified but no HUGETLB. */ 127 if (((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) || 128 __bitcount(flags & MFD_HUGE_MASK) > 1) 129 return (EINVAL); 130 131 /* We've already validated that we're sufficiently sized. */ 132 snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name); 133 oflags = O_RDWR; 134 shmflags = SHM_GROW_ON_WRITE; 135 if ((flags & MFD_CLOEXEC) != 0) 136 oflags |= O_CLOEXEC; 137 if ((flags & MFD_ALLOW_SEALING) != 0) 138 shmflags |= SHM_ALLOW_SEALING; 139 if ((flags & MFD_HUGETLB) != 0) 140 shmflags |= SHM_LARGEPAGE; 141 fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name); 142 if (fd == -1 || (flags & MFD_HUGETLB) == 0) 143 return (fd); 144 145 pgs = NULL; 146 npgs = getpagesizes(NULL, 0); 147 if (npgs == -1) 148 goto clean; 149 pgs = calloc(npgs, sizeof(size_t)); 150 if (pgs == NULL) 151 goto clean; 152 error = getpagesizes(pgs, npgs); 153 if (error == -1) 154 goto clean; 155 if ((flags & MFD_HUGE_MASK) == 0) { 156 if (npgs == 1) { 157 errno = EOPNOTSUPP; 158 goto clean; 159 } 160 pgidx = 1; 161 } else { 162 for (i = 0; i < nitems(mfd_huge_sizes); i++) { 163 if (mfd_huge_sizes[i].mask == (flags & MFD_HUGE_MASK)) 164 break; 165 } 166 for (pgidx = 0; pgidx < npgs; pgidx++) { 167 if (mfd_huge_sizes[i].pgsize == pgs[pgidx]) 168 break; 169 } 170 if (pgidx == npgs) { 171 errno = EOPNOTSUPP; 172 goto clean; 173 } 174 } 175 free(pgs); 176 pgs = NULL; 177 178 memset(&slc, 0, sizeof(slc)); 179 slc.psind = pgidx; 180 slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT; 181 error = ioctl(fd, FIOSSHMLPGCNF, &slc); 182 if (error == -1) 183 goto clean; 184 return (fd); 185 186 clean: 187 saved_errno = errno; 188 close(fd); 189 free(pgs); 190 errno = saved_errno; 191 return (-1); 192 } 193