blob: 0b9eafb7ab7bc1cc0282a4eec26bad50786a23fe [file] [log] [blame]
#define _GNU_SOURCE
#define __EXPORTED_HEADERS__
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/falloc.h>
#include <linux/fcntl.h>
#include <linux/memfd.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>
#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65535
static int sys_memfd_create(const char *name,
unsigned int flags)
{
return syscall(__NR_memfd_create, name, flags);
}
static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
{
int r, fd;
fd = sys_memfd_create(name, flags);
if (fd < 0) {
printf("memfd_create(\"%s\", %u) failed: %m\n",
name, flags);
abort();
}
r = ftruncate(fd, sz);
if (r < 0) {
printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
abort();
}
return fd;
}
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
r = sys_memfd_create(name, flags);
if (r >= 0) {
printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
name, flags);
close(r);
abort();
}
}
static unsigned int mfd_assert_get_seals(int fd)
{
int r;
r = fcntl(fd, F_GET_SEALS);
if (r < 0) {
printf("GET_SEALS(%d) failed: %m\n", fd);
abort();
}
return (unsigned int)r;
}
static void mfd_assert_has_seals(int fd, unsigned int seals)
{
unsigned int s;
s = mfd_assert_get_seals(fd);
if (s != seals) {
printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
abort();
}
}
static void mfd_assert_add_seals(int fd, unsigned int seals)
{
int r;
unsigned int s;
s = mfd_assert_get_seals(fd);
r = fcntl(fd, F_ADD_SEALS, seals);
if (r < 0) {
printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
abort();
}
}
static void mfd_fail_add_seals(int fd, unsigned int seals)
{
int r;
unsigned int s;
r = fcntl(fd, F_GET_SEALS);
if (r < 0)
s = 0;
else
s = (unsigned int)r;
r = fcntl(fd, F_ADD_SEALS, seals);
if (r >= 0) {
printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
fd, s, seals);
abort();
}
}
static void mfd_assert_size(int fd, size_t size)
{
struct stat st;
int r;
r = fstat(fd, &st);
if (r < 0) {
printf("fstat(%d) failed: %m\n", fd);
abort();
} else if (st.st_size != size) {
printf("wrong file size %lld, but expected %lld\n",
(long long)st.st_size, (long long)size);
abort();
}
}
static int mfd_assert_dup(int fd)
{
int r;
r = dup(fd);
if (r < 0) {
printf("dup(%d) failed: %m\n", fd);
abort();
}
return r;
}
static void *mfd_assert_mmap_shared(int fd)
{
void *p;
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
return p;
}
static void *mfd_assert_mmap_private(int fd)
{
void *p;
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ,
MAP_PRIVATE,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
return p;
}
static int mfd_assert_open(int fd, int flags, mode_t mode)
{
char buf[512];
int r;
sprintf(buf, "/proc/self/fd/%d", fd);
r = open(buf, flags, mode);
if (r < 0) {
printf("open(%s) failed: %m\n", buf);
abort();
}
return r;
}
static void mfd_fail_open(int fd, int flags, mode_t mode)
{
char buf[512];
int r;
sprintf(buf, "/proc/self/fd/%d", fd);
r = open(buf, flags, mode);
if (r >= 0) {
printf("open(%s) didn't fail as expected\n", buf);
abort();
}
}
static void mfd_assert_read(int fd)
{
char buf[16];
void *p;
ssize_t l;
l = read(fd, buf, sizeof(buf));
if (l != sizeof(buf)) {
printf("read() failed: %m\n");
abort();
}
/* verify PROT_READ *is* allowed */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ,
MAP_PRIVATE,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
munmap(p, MFD_DEF_SIZE);
/* verify MAP_PRIVATE is *always* allowed (even writable) */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ | PROT_WRITE,
MAP_PRIVATE,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
munmap(p, MFD_DEF_SIZE);
}
static void mfd_assert_write(int fd)
{
ssize_t l;
void *p;
int r;
/* verify write() succeeds */
l = write(fd, "\0\0\0\0", 4);
if (l != 4) {
printf("write() failed: %m\n");
abort();
}
/* verify PROT_READ | PROT_WRITE is allowed */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
*(char *)p = 0;
munmap(p, MFD_DEF_SIZE);
/* verify PROT_WRITE is allowed */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_WRITE,
MAP_SHARED,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
*(char *)p = 0;
munmap(p, MFD_DEF_SIZE);
/* verify PROT_READ with MAP_SHARED is allowed and a following
* mprotect(PROT_WRITE) allows writing */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ,
MAP_SHARED,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
if (r < 0) {
printf("mprotect() failed: %m\n");
abort();
}
*(char *)p = 0;
munmap(p, MFD_DEF_SIZE);
/* verify PUNCH_HOLE works */
r = fallocate(fd,
FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
0,
MFD_DEF_SIZE);
if (r < 0) {
printf("fallocate(PUNCH_HOLE) failed: %m\n");
abort();
}
}
static void mfd_fail_write(int fd)
{
ssize_t l;
void *p;
int r;
/* verify write() fails */
l = write(fd, "data", 4);
if (l != -EPERM) {
printf("expected EPERM on write(), but got %d: %m\n", (int)l);
abort();
}
/* verify PROT_READ | PROT_WRITE is not allowed */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd,
0);
if (p != MAP_FAILED) {
printf("mmap() didn't fail as expected\n");
abort();
}
/* verify PROT_WRITE is not allowed */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_WRITE,
MAP_SHARED,
fd,
0);
if (p != MAP_FAILED) {
printf("mmap() didn't fail as expected\n");
abort();
}
/* Verify PROT_READ with MAP_SHARED with a following mprotect is not
* allowed. Note that for r/w the kernel already prevents the mmap. */
p = mmap(NULL,
MFD_DEF_SIZE,
PROT_READ,
MAP_SHARED,
fd,
0);
if (p != MAP_FAILED) {
r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
if (r >= 0) {
printf("mmap()+mprotect() didn't fail as expected\n");
abort();
}
}
/* verify PUNCH_HOLE fails */
r = fallocate(fd,
FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
0,
MFD_DEF_SIZE);
if (r >= 0) {
printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
abort();
}
}
static void mfd_assert_shrink(int fd)
{
int r, fd2;
r = ftruncate(fd, MFD_DEF_SIZE / 2);
if (r < 0) {
printf("ftruncate(SHRINK) failed: %m\n");
abort();
}
mfd_assert_size(fd, MFD_DEF_SIZE / 2);
fd2 = mfd_assert_open(fd,
O_RDWR | O_CREAT | O_TRUNC,
S_IRUSR | S_IWUSR);
close(fd2);
mfd_assert_size(fd, 0);
}
static void mfd_fail_shrink(int fd)
{
int r;
r = ftruncate(fd, MFD_DEF_SIZE / 2);
if (r >= 0) {
printf("ftruncate(SHRINK) didn't fail as expected\n");
abort();
}
mfd_fail_open(fd,
O_RDWR | O_CREAT | O_TRUNC,
S_IRUSR | S_IWUSR);
}
static void mfd_assert_grow(int fd)
{
int r;
r = ftruncate(fd, MFD_DEF_SIZE * 2);
if (r < 0) {
printf("ftruncate(GROW) failed: %m\n");
abort();
}
mfd_assert_size(fd, MFD_DEF_SIZE * 2);
r = fallocate(fd,
0,
0,
MFD_DEF_SIZE * 4);
if (r < 0) {
printf("fallocate(ALLOC) failed: %m\n");
abort();
}
mfd_assert_size(fd, MFD_DEF_SIZE * 4);
}
static void mfd_fail_grow(int fd)
{
int r;
r = ftruncate(fd, MFD_DEF_SIZE * 2);
if (r >= 0) {
printf("ftruncate(GROW) didn't fail as expected\n");
abort();
}
r = fallocate(fd,
0,
0,
MFD_DEF_SIZE * 4);
if (r >= 0) {
printf("fallocate(ALLOC) didn't fail as expected\n");
abort();
}
}
static void mfd_assert_grow_write(int fd)
{
static char buf[MFD_DEF_SIZE * 8];
ssize_t l;
l = pwrite(fd, buf, sizeof(buf), 0);
if (l != sizeof(buf)) {
printf("pwrite() failed: %m\n");
abort();
}
mfd_assert_size(fd, MFD_DEF_SIZE * 8);
}
static void mfd_fail_grow_write(int fd)
{
static char buf[MFD_DEF_SIZE * 8];
ssize_t l;
l = pwrite(fd, buf, sizeof(buf), 0);
if (l == sizeof(buf)) {
printf("pwrite() didn't fail as expected\n");
abort();
}
}
static int idle_thread_fn(void *arg)
{
sigset_t set;
int sig;
/* dummy waiter; SIGTERM terminates us anyway */
sigemptyset(&set);
sigaddset(&set, SIGTERM);
sigwait(&set, &sig);
return 0;
}
static pid_t spawn_idle_thread(unsigned int flags)
{
uint8_t *stack;
pid_t pid;
stack = malloc(STACK_SIZE);
if (!stack) {
printf("malloc(STACK_SIZE) failed: %m\n");
abort();
}
pid = clone(idle_thread_fn,
stack + STACK_SIZE,
SIGCHLD | flags,
NULL);
if (pid < 0) {
printf("clone() failed: %m\n");
abort();
}
return pid;
}
static void join_idle_thread(pid_t pid)
{
kill(pid, SIGTERM);
waitpid(pid, NULL, 0);
}
/*
* Test memfd_create() syscall
* Verify syscall-argument validation, including name checks, flag validation
* and more.
*/
static void test_create(void)
{
char buf[2048];
int fd;
/* test NULL name */
mfd_fail_new(NULL, 0);
/* test over-long name (not zero-terminated) */
memset(buf, 0xff, sizeof(buf));
mfd_fail_new(buf, 0);
/* test over-long zero-terminated name */
memset(buf, 0xff, sizeof(buf));
buf[sizeof(buf) - 1] = 0;
mfd_fail_new(buf, 0);
/* verify "" is a valid name */
fd = mfd_assert_new("", 0, 0);
close(fd);
/* verify invalid O_* open flags */
mfd_fail_new("", 0x0100);
mfd_fail_new("", ~MFD_CLOEXEC);
mfd_fail_new("", ~MFD_ALLOW_SEALING);
mfd_fail_new("", ~0);
mfd_fail_new("", 0x80000000U);
/* verify MFD_CLOEXEC is allowed */
fd = mfd_assert_new("", 0, MFD_CLOEXEC);
close(fd);
/* verify MFD_ALLOW_SEALING is allowed */
fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
close(fd);
/* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
close(fd);
}
/*
* Test basic sealing
* A very basic sealing test to see whether setting/retrieving seals works.
*/
static void test_basic(void)
{
int fd;
fd = mfd_assert_new("kern_memfd_basic",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
/* add basic seals */
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_SHRINK |
F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_SHRINK |
F_SEAL_WRITE);
/* add them again */
mfd_assert_add_seals(fd, F_SEAL_SHRINK |
F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_SHRINK |
F_SEAL_WRITE);
/* add more seals and seal against sealing */
mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
mfd_assert_has_seals(fd, F_SEAL_SHRINK |
F_SEAL_GROW |
F_SEAL_WRITE |
F_SEAL_SEAL);
/* verify that sealing no longer works */
mfd_fail_add_seals(fd, F_SEAL_GROW);
mfd_fail_add_seals(fd, 0);
close(fd);
/* verify sealing does not work without MFD_ALLOW_SEALING */
fd = mfd_assert_new("kern_memfd_basic",
MFD_DEF_SIZE,
MFD_CLOEXEC);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
mfd_fail_add_seals(fd, F_SEAL_SHRINK |
F_SEAL_GROW |
F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
close(fd);
}
/*
* Test SEAL_WRITE
* Test whether SEAL_WRITE actually prevents modifications.
*/
static void test_seal_write(void)
{
int fd;
fd = mfd_assert_new("kern_memfd_seal_write",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_WRITE);
mfd_assert_read(fd);
mfd_fail_write(fd);
mfd_assert_shrink(fd);
mfd_assert_grow(fd);
mfd_fail_grow_write(fd);
close(fd);
}
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
*/
static void test_seal_shrink(void)
{
int fd;
fd = mfd_assert_new("kern_memfd_seal_shrink",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_SHRINK);
mfd_assert_has_seals(fd, F_SEAL_SHRINK);
mfd_assert_read(fd);
mfd_assert_write(fd);
mfd_fail_shrink(fd);
mfd_assert_grow(fd);
mfd_assert_grow_write(fd);
close(fd);
}
/*
* Test SEAL_GROW
* Test whether SEAL_GROW actually prevents growing
*/
static void test_seal_grow(void)
{
int fd;
fd = mfd_assert_new("kern_memfd_seal_grow",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_GROW);
mfd_assert_has_seals(fd, F_SEAL_GROW);
mfd_assert_read(fd);
mfd_assert_write(fd);
mfd_assert_shrink(fd);
mfd_fail_grow(fd);
mfd_fail_grow_write(fd);
close(fd);
}
/*
* Test SEAL_SHRINK | SEAL_GROW
* Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
*/
static void test_seal_resize(void)
{
int fd;
fd = mfd_assert_new("kern_memfd_seal_resize",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
mfd_assert_read(fd);
mfd_assert_write(fd);
mfd_fail_shrink(fd);
mfd_fail_grow(fd);
mfd_fail_grow_write(fd);
close(fd);
}
/*
* Test sharing via dup()
* Test that seals are shared between dupped FDs and they're all equal.
*/
static void test_share_dup(void)
{
int fd, fd2;
fd = mfd_assert_new("kern_memfd_share_dup",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
fd2 = mfd_assert_dup(fd);
mfd_assert_has_seals(fd2, 0);
mfd_assert_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd2, F_SEAL_WRITE);
mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
mfd_assert_add_seals(fd, F_SEAL_SEAL);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
mfd_fail_add_seals(fd, F_SEAL_GROW);
mfd_fail_add_seals(fd2, F_SEAL_GROW);
mfd_fail_add_seals(fd, F_SEAL_SEAL);
mfd_fail_add_seals(fd2, F_SEAL_SEAL);
close(fd2);
mfd_fail_add_seals(fd, F_SEAL_GROW);
close(fd);
}
/*
* Test sealing with active mmap()s
* Modifying seals is only allowed if no other mmap() refs exist.
*/
static void test_share_mmap(void)
{
int fd;
void *p;
fd = mfd_assert_new("kern_memfd_share_mmap",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
/* shared/writable ref prevents sealing WRITE, but allows others */
p = mfd_assert_mmap_shared(fd);
mfd_fail_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_SHRINK);
mfd_assert_has_seals(fd, F_SEAL_SHRINK);
munmap(p, MFD_DEF_SIZE);
/* readable ref allows sealing */
p = mfd_assert_mmap_private(fd);
mfd_assert_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
munmap(p, MFD_DEF_SIZE);
close(fd);
}
/*
* Test sealing with open(/proc/self/fd/%d)
* Via /proc we can get access to a separate file-context for the same memfd.
* This is *not* like dup(), but like a real separate open(). Make sure the
* semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
*/
static void test_share_open(void)
{
int fd, fd2;
fd = mfd_assert_new("kern_memfd_share_open",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
fd2 = mfd_assert_open(fd, O_RDWR, 0);
mfd_assert_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd2, F_SEAL_WRITE);
mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
close(fd);
fd = mfd_assert_open(fd2, O_RDONLY, 0);
mfd_fail_add_seals(fd, F_SEAL_SEAL);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
close(fd2);
fd2 = mfd_assert_open(fd, O_RDWR, 0);
mfd_assert_add_seals(fd2, F_SEAL_SEAL);
mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
close(fd2);
close(fd);
}
/*
* Test sharing via fork()
* Test whether seal-modifications work as expected with forked childs.
*/
static void test_share_fork(void)
{
int fd;
pid_t pid;
fd = mfd_assert_new("kern_memfd_share_fork",
MFD_DEF_SIZE,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_has_seals(fd, 0);
pid = spawn_idle_thread(0);
mfd_assert_add_seals(fd, F_SEAL_SEAL);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
mfd_fail_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
join_idle_thread(pid);
mfd_fail_add_seals(fd, F_SEAL_WRITE);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
close(fd);
}
int main(int argc, char **argv)
{
pid_t pid;
printf("memfd: CREATE\n");
test_create();
printf("memfd: BASIC\n");
test_basic();
printf("memfd: SEAL-WRITE\n");
test_seal_write();
printf("memfd: SEAL-SHRINK\n");
test_seal_shrink();
printf("memfd: SEAL-GROW\n");
test_seal_grow();
printf("memfd: SEAL-RESIZE\n");
test_seal_resize();
printf("memfd: SHARE-DUP\n");
test_share_dup();
printf("memfd: SHARE-MMAP\n");
test_share_mmap();
printf("memfd: SHARE-OPEN\n");
test_share_open();
printf("memfd: SHARE-FORK\n");
test_share_fork();
/* Run test-suite in a multi-threaded environment with a shared
* file-table. */
pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
printf("memfd: SHARE-DUP (shared file-table)\n");
test_share_dup();
printf("memfd: SHARE-MMAP (shared file-table)\n");
test_share_mmap();
printf("memfd: SHARE-OPEN (shared file-table)\n");
test_share_open();
printf("memfd: SHARE-FORK (shared file-table)\n");
test_share_fork();
join_idle_thread(pid);
printf("memfd: DONE\n");
return 0;
}