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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#if HAVE_LINUX_MEMFD_H
#include <linux/memfd.h>
#endif
#include <stdio.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "macro.h"
#include "memfd-util.h"
#include "missing.h"
#include "string-util.h"
#include "utf8.h"
int memfd_new(const char *name) {
_cleanup_free_ char *g = NULL;
int fd;
if (!name) {
char pr[17] = {};
/* If no name is specified we generate one. We include
* a hint indicating our library implementation, and
* add the thread name to it */
assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0);
if (isempty(pr))
name = "sd";
else {
_cleanup_free_ char *e = NULL;
e = utf8_escape_invalid(pr);
if (!e)
return -ENOMEM;
g = strappend("sd-", e);
if (!g)
return -ENOMEM;
name = g;
}
}
fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC);
if (fd < 0)
return -errno;
return fd;
}
int memfd_map(int fd, uint64_t offset, size_t size, void **p) {
void *q;
int sealed;
assert(fd >= 0);
assert(size > 0);
assert(p);
sealed = memfd_get_sealed(fd);
if (sealed < 0)
return sealed;
if (sealed)
q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset);
else
q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
if (q == MAP_FAILED)
return -errno;
*p = q;
return 0;
}
int memfd_set_sealed(int fd) {
int r;
assert(fd >= 0);
r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL);
if (r < 0)
return -errno;
return 0;
}
int memfd_get_sealed(int fd) {
int r;
assert(fd >= 0);
r = fcntl(fd, F_GET_SEALS);
if (r < 0)
return -errno;
return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL);
}
int memfd_get_size(int fd, uint64_t *sz) {
struct stat stat;
int r;
assert(fd >= 0);
assert(sz);
r = fstat(fd, &stat);
if (r < 0)
return -errno;
*sz = stat.st_size;
return 0;
}
int memfd_set_size(int fd, uint64_t sz) {
int r;
assert(fd >= 0);
r = ftruncate(fd, sz);
if (r < 0)
return -errno;
return 0;
}
int memfd_new_and_map(const char *name, size_t sz, void **p) {
_cleanup_close_ int fd = -1;
int r;
assert(sz > 0);
assert(p);
fd = memfd_new(name);
if (fd < 0)
return fd;
r = memfd_set_size(fd, sz);
if (r < 0)
return r;
r = memfd_map(fd, 0, sz, p);
if (r < 0)
return r;
return TAKE_FD(fd);
}
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