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memfd_create: move implementation to libc/gen
Due to memfd_create(3)'s construction of a path to pass to shm_open2(2), it has a much larger than typical dependency footprint for a system call wrapper (the list currently includes calloc, memset, sprintf, and strlen). As such, split it off into its own file under libc/gen to lighten libc/sys's dependency list. Reviewed by: kevans, imp, emaste Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D42709
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,131 @@ | ||
| /* | ||
| * SPDX-License-Identifier: BSD-2-Clause | ||
| * | ||
| * Copyright (c) 2019 Kyle Evans <kevans@FreeBSD.org> | ||
| * | ||
| * Redistribution and use in source and binary forms, with or without | ||
| * modification, are permitted provided that the following conditions | ||
| * are met: | ||
| * 1. Redistributions of source code must retain the above copyright | ||
| * notice(s), this list of conditions and the following disclaimer as | ||
| * the first lines of this file unmodified other than the possible | ||
| * addition of one or more copyright notices. | ||
| * 2. Redistributions in binary form must reproduce the above copyright | ||
| * notice(s), this list of conditions and the following disclaimer in | ||
| * the documentation and/or other materials provided with the | ||
| * distribution. | ||
| * | ||
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY | ||
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | ||
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE | ||
| * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | ||
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | ||
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR | ||
| * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | ||
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE | ||
| * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, | ||
| * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
| */ | ||
|
|
||
| #include <sys/param.h> | ||
| #include <sys/filio.h> | ||
| #include <sys/mman.h> | ||
|
|
||
| #include <errno.h> | ||
| #include <fcntl.h> | ||
| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <string.h> | ||
| #include <unistd.h> | ||
|
|
||
| #include "libc_private.h" | ||
|
|
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| #define MEMFD_NAME_PREFIX "memfd:" | ||
|
|
||
| /* | ||
| * The path argument is passed to the kernel, but the kernel doesn't currently | ||
| * do anything with it. Linux exposes it in linprocfs for debugging purposes | ||
| * only, but our kernel currently will not do the same. | ||
| */ | ||
| int | ||
| memfd_create(const char *name, unsigned int flags) | ||
| { | ||
| char memfd_name[NAME_MAX + 1]; | ||
| size_t namelen, *pgs, pgsize; | ||
| struct shm_largepage_conf slc; | ||
| int error, fd, npgs, oflags, pgidx, saved_errno, shmflags; | ||
|
|
||
| if (name == NULL) { | ||
| errno = EBADF; | ||
| return (-1); | ||
| } | ||
| namelen = strlen(name); | ||
| if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) { | ||
| errno = EINVAL; | ||
| return (-1); | ||
| } | ||
| if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | | ||
| MFD_HUGE_MASK)) != 0) { | ||
| errno = EINVAL; | ||
| return (-1); | ||
| } | ||
| /* Size specified but no HUGETLB. */ | ||
| if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) { | ||
| errno = EINVAL; | ||
| return (-1); | ||
| } | ||
|
|
||
| /* We've already validated that we're sufficiently sized. */ | ||
| snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name); | ||
| oflags = O_RDWR; | ||
| shmflags = 0; | ||
| if ((flags & MFD_CLOEXEC) != 0) | ||
| oflags |= O_CLOEXEC; | ||
| if ((flags & MFD_ALLOW_SEALING) != 0) | ||
| shmflags |= SHM_ALLOW_SEALING; | ||
| if ((flags & MFD_HUGETLB) != 0) | ||
| shmflags |= SHM_LARGEPAGE; | ||
| else | ||
| shmflags |= SHM_GROW_ON_WRITE; | ||
| fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name); | ||
| if (fd == -1 || (flags & MFD_HUGETLB) == 0) | ||
| return (fd); | ||
|
|
||
| pgs = NULL; | ||
| npgs = getpagesizes(NULL, 0); | ||
| if (npgs == -1) | ||
| goto clean; | ||
| pgs = calloc(npgs, sizeof(size_t)); | ||
| if (pgs == NULL) | ||
| goto clean; | ||
| error = getpagesizes(pgs, npgs); | ||
| if (error == -1) | ||
| goto clean; | ||
| pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT); | ||
| for (pgidx = 0; pgidx < npgs; pgidx++) { | ||
| if (pgsize == pgs[pgidx]) | ||
| break; | ||
| } | ||
| if (pgidx == npgs) { | ||
| errno = EOPNOTSUPP; | ||
| goto clean; | ||
| } | ||
| free(pgs); | ||
| pgs = NULL; | ||
|
|
||
| memset(&slc, 0, sizeof(slc)); | ||
| slc.psind = pgidx; | ||
| slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT; | ||
| error = ioctl(fd, FIOSSHMLPGCNF, &slc); | ||
| if (error == -1) | ||
| goto clean; | ||
| return (fd); | ||
|
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||
| clean: | ||
| saved_errno = errno; | ||
| close(fd); | ||
| free(pgs); | ||
| errno = saved_errno; | ||
| return (-1); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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|
@@ -409,7 +409,6 @@ FBSD_1.6 { | |
| fhreadlink; | ||
| getfhat; | ||
| funlinkat; | ||
| memfd_create; | ||
| shm_create_largepage; | ||
| shm_rename; | ||
| }; | ||
|
|
||
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