// SPDX-License-Identifier: GPL-2.0
#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 <sys/wait.h>
#include <unistd.h>

#include "common.h"

#define MEMFD_STR       "memfd:"
#define MEMFD_HUGE_STR  "memfd-hugetlb:"
#define SHARED_FT_STR   "(shared file-table)"

#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65536

/*
 * Default is not to test hugetlbfs
 */
static size_t mfd_def_size = MFD_DEF_SIZE;
static const char *memfd_str = MEMFD_STR;

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 int mfd_assert_reopen_fd(int fd_in)
{
        int r, fd;
        char path[100];

        sprintf(path, "/proc/self/fd/%d", fd_in);

        fd = open(path, O_RDWR);
        if (fd < 0) {
                printf("re-open of existing fd %d failed\n", fd_in);
                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);
}

/* Test that PROT_READ + MAP_SHARED mappings work. */
static void mfd_assert_read_shared(int fd)
{
        void *p;

        /* verify PROT_READ and MAP_SHARED *is* allowed */
        p = mmap(NULL,
                 mfd_def_size,
                 PROT_READ,
                 MAP_SHARED,
                 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;

        /*
         * huegtlbfs does not support write, but we want to
         * verify everything else here.
         */
        if (!hugetlbfs_test) {
                /* 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;
        ssize_t l;

        /* hugetlbfs does not support write */
        if (hugetlbfs_test)
                return;

        buf = malloc(mfd_def_size * 8);
        if (!buf) {
                printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
                abort();
        }

        l = pwrite(fd, buf, mfd_def_size * 8, 0);
        if (l != (mfd_def_size * 8)) {
                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;
        ssize_t l;

        /* hugetlbfs does not support write */
        if (hugetlbfs_test)
                return;

        buf = malloc(mfd_def_size * 8);
        if (!buf) {
                printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
                abort();
        }

        l = pwrite(fd, buf, mfd_def_size * 8, 0);
        if (l == (mfd_def_size * 8)) {
                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;

        printf("%s CREATE\n", memfd_str);

        /* 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;

        printf("%s BASIC\n", memfd_str);

        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;

        printf("%s SEAL-WRITE\n", memfd_str);

        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_FUTURE_WRITE
 * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
 */
static void test_seal_future_write(void)
{
        int fd, fd2;
        void *p;

        printf("%s SEAL-FUTURE-WRITE\n", memfd_str);

        fd = mfd_assert_new("kern_memfd_seal_future_write",
                            mfd_def_size,
                            MFD_CLOEXEC | MFD_ALLOW_SEALING);

        p = mfd_assert_mmap_shared(fd);

        mfd_assert_has_seals(fd, 0);

        mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
        mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);

        /* read should pass, writes should fail */
        mfd_assert_read(fd);
        mfd_assert_read_shared(fd);
        mfd_fail_write(fd);

        fd2 = mfd_assert_reopen_fd(fd);
        /* read should pass, writes should still fail */
        mfd_assert_read(fd2);
        mfd_assert_read_shared(fd2);
        mfd_fail_write(fd2);

        munmap(p, mfd_def_size);
        close(fd2);
        close(fd);
}

/*
 * Test SEAL_SHRINK
 * Test whether SEAL_SHRINK actually prevents shrinking
 */
static void test_seal_shrink(void)
{
        int fd;

        printf("%s SEAL-SHRINK\n", memfd_str);

        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;

        printf("%s SEAL-GROW\n", memfd_str);

        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;

        printf("%s SEAL-RESIZE\n", memfd_str);

        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(char *banner, char *b_suffix)
{
        int fd, fd2;

        printf("%s %s %s\n", memfd_str, banner, b_suffix);

        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(char *banner, char *b_suffix)
{
        int fd;
        void *p;

        printf("%s %s %s\n", memfd_str,  banner, b_suffix);

        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(char *banner, char *b_suffix)
{
        int fd, fd2;

        printf("%s %s %s\n", memfd_str, banner, b_suffix);

        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(char *banner, char *b_suffix)
{
        int fd;
        pid_t pid;

        printf("%s %s %s\n", memfd_str, banner, b_suffix);

        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;

        if (argc == 2) {
                if (!strcmp(argv[1], "hugetlbfs")) {

                        unsigned long hpage_size = default_huge_page_size();

                        if (!hpage_size) {
                                printf("Unable to determine huge page size\n");
                                abort();
                        }

                        hugetlbfs_test = 1;
                        memfd_str = MEMFD_HUGE_STR;
                        mfd_def_size = hpage_size * 2;
                } else {
                        printf("Unknown option: %s\n", argv[1]);
                        abort();
                }
        }

        test_create();
        test_basic();

        test_seal_write();
        test_seal_future_write();
        test_seal_shrink();
        test_seal_grow();
        test_seal_resize();

        test_share_dup("SHARE-DUP", "");
        test_share_mmap("SHARE-MMAP", "");
        test_share_open("SHARE-OPEN", "");
        test_share_fork("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);
        test_share_dup("SHARE-DUP", SHARED_FT_STR);
        test_share_mmap("SHARE-MMAP", SHARED_FT_STR);
        test_share_open("SHARE-OPEN", SHARED_FT_STR);
        test_share_fork("SHARE-FORK", SHARED_FT_STR);
        join_idle_thread(pid);

        printf("memfd: DONE\n");

        return 0;
}