blob: 780be328afcf56568d7c995ee46aeb450d6f4354 [file] [log] [blame]
/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "memfd.h"
#include <errno.h>
#include <stdio.h>
#if !defined(_WIN32)
#include <sys/syscall.h>
#include <sys/utsname.h>
#include <unistd.h>
#endif
#include "macros.h"
// When building for linux host, glibc in prebuilts does not include memfd_create system call
// number. As a temporary testing measure, we add the definition here.
#if defined(__linux__) && !defined(__NR_memfd_create)
#if defined(__x86_64__)
#define __NR_memfd_create 319
#elif defined(__i386__)
#define __NR_memfd_create 356
#endif // defined(__i386__)
#endif // defined(__linux__) && !defined(__NR_memfd_create)
namespace art {
#if defined(__NR_memfd_create)
int memfd_create(const char* name, unsigned int flags) {
// Check kernel version supports memfd_create(). Some older kernels segfault executing
// memfd_create() rather than returning ENOSYS (b/116769556).
static constexpr int kRequiredMajor = 3;
static constexpr int kRequiredMinor = 17;
struct utsname uts;
int major, minor;
if (uname(&uts) != 0 ||
strcmp(uts.sysname, "Linux") != 0 ||
sscanf(uts.release, "%d.%d", &major, &minor) != 2 ||
(major < kRequiredMajor || (major == kRequiredMajor && minor < kRequiredMinor))) {
errno = ENOSYS;
return -1;
}
return syscall(__NR_memfd_create, name, flags);
}
#else // __NR_memfd_create
int memfd_create(const char* name ATTRIBUTE_UNUSED, unsigned int flags ATTRIBUTE_UNUSED) {
errno = ENOSYS;
return -1;
}
#endif // __NR_memfd_create
} // namespace art