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/param.h> 32 #include <sys/filio.h> 33 #include <sys/mman.h> 34 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <limits.h> 38 #include <stdlib.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <unistd.h> 42 43 #include "libc_private.h" 44 45 __weak_reference(shm_open, _shm_open); 46 __weak_reference(shm_open, __sys_shm_open); 47 48 #define MEMFD_NAME_PREFIX "memfd:" 49 50 int 51 shm_open(const char *path, int flags, mode_t mode) 52 { 53 54 return (__sys_shm_open2(path, flags | O_CLOEXEC, mode, 0, NULL)); 55 } 56 57 int 58 shm_create_largepage(const char *path, int flags, int psind, int alloc_policy, 59 mode_t mode) 60 { 61 struct shm_largepage_conf slc; 62 int error, fd, saved_errno; 63 64 fd = __sys_shm_open2(path, flags | O_CREAT, mode, SHM_LARGEPAGE, NULL); 65 if (fd == -1) 66 return (-1); 67 68 memset(&slc, 0, sizeof(slc)); 69 slc.psind = psind; 70 slc.alloc_policy = alloc_policy; 71 error = ioctl(fd, FIOSSHMLPGCNF, &slc); 72 if (error == -1) { 73 saved_errno = errno; 74 close(fd); 75 errno = saved_errno; 76 return (-1); 77 } 78 return (fd); 79 } 80 81 /* 82 * The path argument is passed to the kernel, but the kernel doesn't currently 83 * do anything with it. Linux exposes it in linprocfs for debugging purposes 84 * only, but our kernel currently will not do the same. 85 */ 86 int 87 memfd_create(const char *name, unsigned int flags) 88 { 89 char memfd_name[NAME_MAX + 1]; 90 size_t namelen, *pgs, pgsize; 91 struct shm_largepage_conf slc; 92 int error, fd, npgs, oflags, pgidx, saved_errno, shmflags; 93 94 if (name == NULL) { 95 errno = EBADF; 96 return (-1); 97 } 98 namelen = strlen(name); 99 if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) { 100 errno = EINVAL; 101 return (-1); 102 } 103 if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | 104 MFD_HUGE_MASK)) != 0) { 105 errno = EINVAL; 106 return (-1); 107 } 108 /* Size specified but no HUGETLB. */ 109 if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) { 110 errno = EINVAL; 111 return (-1); 112 } 113 114 /* We've already validated that we're sufficiently sized. */ 115 snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name); 116 oflags = O_RDWR; 117 shmflags = 0; 118 if ((flags & MFD_CLOEXEC) != 0) 119 oflags |= O_CLOEXEC; 120 if ((flags & MFD_ALLOW_SEALING) != 0) 121 shmflags |= SHM_ALLOW_SEALING; 122 if ((flags & MFD_HUGETLB) != 0) 123 shmflags |= SHM_LARGEPAGE; 124 else 125 shmflags |= SHM_GROW_ON_WRITE; 126 fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name); 127 if (fd == -1 || (flags & MFD_HUGETLB) == 0) 128 return (fd); 129 130 pgs = NULL; 131 npgs = getpagesizes(NULL, 0); 132 if (npgs == -1) 133 goto clean; 134 pgs = calloc(npgs, sizeof(size_t)); 135 if (pgs == NULL) 136 goto clean; 137 error = getpagesizes(pgs, npgs); 138 if (error == -1) 139 goto clean; 140 pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT); 141 for (pgidx = 0; pgidx < npgs; pgidx++) { 142 if (pgsize == pgs[pgidx]) 143 break; 144 } 145 if (pgidx == npgs) { 146 errno = EOPNOTSUPP; 147 goto clean; 148 } 149 free(pgs); 150 pgs = NULL; 151 152 memset(&slc, 0, sizeof(slc)); 153 slc.psind = pgidx; 154 slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT; 155 error = ioctl(fd, FIOSSHMLPGCNF, &slc); 156 if (error == -1) 157 goto clean; 158 return (fd); 159 160 clean: 161 saved_errno = errno; 162 close(fd); 163 free(pgs); 164 errno = saved_errno; 165 return (-1); 166 } 167