+static int
+legacy_memfd_create (u8 * name)
+{
+ clib_mem_main_t *mm = &clib_mem_main;
+ int fd = -1;
+ char *mount_dir;
+ u8 *filename;
+
+ /* create mount directory */
+ if ((mount_dir = mkdtemp ("/tmp/hugepage_mount.XXXXXX")) == 0)
+ {
+ vec_reset_length (mm->error);
+ mm->error = clib_error_return_unix (mm->error, "mkdtemp");
+ return -1;
+ }
+
+ if (mount ("none", mount_dir, "hugetlbfs", 0, NULL))
+ {
+ rmdir ((char *) mount_dir);
+ vec_reset_length (mm->error);
+ mm->error = clib_error_return_unix (mm->error, "mount");
+ return -1;
+ }
+
+ filename = format (0, "%s/%s%c", mount_dir, name, 0);
+
+ if ((fd = open ((char *) filename, O_CREAT | O_RDWR, 0755)) == -1)
+ {
+ vec_reset_length (mm->error);
+ mm->error = clib_error_return_unix (mm->error, "mkdtemp");
+ }
+
+ umount2 ((char *) mount_dir, MNT_DETACH);
+ rmdir ((char *) mount_dir);
+ vec_free (filename);
+
+ return fd;
+}
+
+int
+clib_mem_vm_create_fd (clib_mem_page_sz_t log2_page_size, char *fmt, ...)
+{
+ clib_mem_main_t *mm = &clib_mem_main;
+ int fd;
+ unsigned int memfd_flags;
+ va_list va;
+ u8 *s = 0;
+
+ if (log2_page_size == mm->log2_page_sz)
+ log2_page_size = CLIB_MEM_PAGE_SZ_DEFAULT;
+
+ switch (log2_page_size)
+ {
+ case CLIB_MEM_PAGE_SZ_UNKNOWN:
+ return -1;
+ case CLIB_MEM_PAGE_SZ_DEFAULT:
+ memfd_flags = MFD_ALLOW_SEALING;
+ break;
+ case CLIB_MEM_PAGE_SZ_DEFAULT_HUGE:
+ memfd_flags = MFD_HUGETLB;
+ break;
+ default:
+ memfd_flags = MFD_HUGETLB | log2_page_size << MFD_HUGE_SHIFT;
+ }
+
+ va_start (va, fmt);
+ s = va_format (0, fmt, &va);
+ va_end (va);
+
+ /* memfd_create maximum string size is 249 chars without trailing zero */
+ if (vec_len (s) > 249)
+ _vec_len (s) = 249;
+ vec_add1 (s, 0);
+
+ /* memfd_create introduced in kernel 3.17, we don't support older kernels */
+ fd = memfd_create ((char *) s, memfd_flags);
+
+ /* kernel versions < 4.14 does not support memfd_create for huge pages */
+ if (fd == -1 && errno == EINVAL &&
+ log2_page_size == CLIB_MEM_PAGE_SZ_DEFAULT_HUGE)
+ {
+ fd = legacy_memfd_create (s);
+ }
+ else if (fd == -1)
+ {
+ vec_reset_length (mm->error);
+ mm->error = clib_error_return_unix (mm->error, "memfd_create");
+ vec_free (s);
+ return -1;
+ }
+
+ vec_free (s);
+
+ if ((memfd_flags & MFD_ALLOW_SEALING) &&
+ ((fcntl (fd, F_ADD_SEALS, F_SEAL_SHRINK)) == -1))
+ {
+ vec_reset_length (mm->error);
+ mm->error = clib_error_return_unix (mm->error, "fcntl (F_ADD_SEALS)");
+ close (fd);
+ return -1;
+ }
+
+ return fd;
+}
+