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/*
* 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 <string.h>
#include <unistd.h>
#include "libc_private.h"
#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 pgs[MAXPAGESIZES];
size_t namelen, 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);
npgs = getpagesizes(pgs, nitems(pgs));
if (npgs == -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;
}
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);
clean:
saved_errno = errno;
close(fd);
errno = saved_errno;
return (-1);
}
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