1 /* 2 * SPDX-License-Identifier: BSD-2-Clause 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 (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 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