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 #include <sys/param.h> 33 #include <sys/filio.h> 34 #include <sys/mman.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <limits.h> 39 #include <stdlib.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #include "libc_private.h" 45 46 __weak_reference(shm_open, _shm_open); 47 __weak_reference(shm_open, __sys_shm_open); 48 49 #define MEMFD_NAME_PREFIX "memfd:" 50 51 int 52 shm_open(const char *path, int flags, mode_t mode) 53 { 54 55 return (__sys_shm_open2(path, flags | O_CLOEXEC, mode, 0, NULL)); 56 } 57 58 int 59 shm_create_largepage(const char *path, int flags, int psind, int alloc_policy, 60 mode_t mode) 61 { 62 struct shm_largepage_conf slc; 63 int error, fd, saved_errno; 64 65 fd = __sys_shm_open2(path, flags | O_CREAT, mode, SHM_LARGEPAGE, NULL); 66 if (fd == -1) 67 return (-1); 68 69 memset(&slc, 0, sizeof(slc)); 70 slc.psind = psind; 71 slc.alloc_policy = alloc_policy; 72 error = ioctl(fd, FIOSSHMLPGCNF, &slc); 73 if (error == -1) { 74 saved_errno = errno; 75 close(fd); 76 errno = saved_errno; 77 return (-1); 78 } 79 return (fd); 80 } 81 82 /* 83 * The path argument is passed to the kernel, but the kernel doesn't currently 84 * do anything with it. Linux exposes it in linprocfs for debugging purposes 85 * only, but our kernel currently will not do the same. 86 */ 87 int 88 memfd_create(const char *name, unsigned int flags) 89 { 90 char memfd_name[NAME_MAX + 1]; 91 size_t namelen, *pgs, pgsize; 92 struct shm_largepage_conf slc; 93 int error, fd, npgs, oflags, pgidx, saved_errno, shmflags; 94 95 if (name == NULL) { 96 errno = EBADF; 97 return (-1); 98 } 99 namelen = strlen(name); 100 if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) { 101 errno = EINVAL; 102 return (-1); 103 } 104 if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | 105 MFD_HUGE_MASK)) != 0) { 106 errno = EINVAL; 107 return (-1); 108 } 109 /* Size specified but no HUGETLB. */ 110 if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) { 111 errno = EINVAL; 112 return (-1); 113 } 114 115 /* We've already validated that we're sufficiently sized. */ 116 snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name); 117 oflags = O_RDWR; 118 shmflags = 0; 119 if ((flags & MFD_CLOEXEC) != 0) 120 oflags |= O_CLOEXEC; 121 if ((flags & MFD_ALLOW_SEALING) != 0) 122 shmflags |= SHM_ALLOW_SEALING; 123 if ((flags & MFD_HUGETLB) != 0) 124 shmflags |= SHM_LARGEPAGE; 125 else 126 shmflags |= SHM_GROW_ON_WRITE; 127 fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name); 128 if (fd == -1 || (flags & MFD_HUGETLB) == 0) 129 return (fd); 130 131 pgs = NULL; 132 npgs = getpagesizes(NULL, 0); 133 if (npgs == -1) 134 goto clean; 135 pgs = calloc(npgs, sizeof(size_t)); 136 if (pgs == NULL) 137 goto clean; 138 error = getpagesizes(pgs, npgs); 139 if (error == -1) 140 goto clean; 141 pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT); 142 for (pgidx = 0; pgidx < npgs; pgidx++) { 143 if (pgsize == pgs[pgidx]) 144 break; 145 } 146 if (pgidx == npgs) { 147 errno = EOPNOTSUPP; 148 goto clean; 149 } 150 free(pgs); 151 pgs = NULL; 152 153 memset(&slc, 0, sizeof(slc)); 154 slc.psind = pgidx; 155 slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT; 156 error = ioctl(fd, FIOSSHMLPGCNF, &slc); 157 if (error == -1) 158 goto clean; 159 return (fd); 160 161 clean: 162 saved_errno = errno; 163 close(fd); 164 free(pgs); 165 errno = saved_errno; 166 return (-1); 167 } 168