From fa2e1897eab8bc6838f0e8bc791a0d7fbaa58972 Mon Sep 17 00:00:00 2001 From: Xiang Xiao Date: Mon, 8 Aug 2022 00:17:41 +0800 Subject: [PATCH] libc: Implement memfd on top of tmpfs https://man7.org/linux/man-pages/man2/memfd_create.2.html Signed-off-by: Xiang Xiao --- include/fcntl.h | 10 ++++++ include/sys/memfd.h | 72 ++++++++++++++++++++++++++++++++++++++ libs/libc/misc/Kconfig | 7 ++++ libs/libc/misc/Make.defs | 2 +- libs/libc/misc/lib_memfd.c | 51 +++++++++++++++++++++++++++ 5 files changed, 141 insertions(+), 1 deletion(-) create mode 100644 include/sys/memfd.h create mode 100644 libs/libc/misc/lib_memfd.c diff --git a/include/fcntl.h b/include/fcntl.h index 25a0cce335e..b6381d0cc98 100644 --- a/include/fcntl.h +++ b/include/fcntl.h @@ -97,6 +97,8 @@ #define F_SETOWN 13 /* Set pid that will receive SIGIO and SIGURG signals for fd */ #define F_SETSIG 14 /* Set the signal to be sent */ #define F_GETPATH 15 /* Get the path of the file descriptor(BSD/macOS) */ +#define F_ADD_SEALS 16 /* Add the bit-mask argument arg to the set of seals of the inode */ +#define F_GET_SEALS 17 /* Get (as the function result) the current set of seals of the inode */ /* For posix fcntl() and lockf() */ @@ -117,6 +119,14 @@ #define DN_RENAME 4 /* A file was renamed */ #define DN_ATTRIB 5 /* Attributes of a file were changed */ +/* Types of seals */ + +#define F_SEAL_SEAL 0x0001 /* Prevent further seals from being set */ +#define F_SEAL_SHRINK 0x0002 /* Prevent file from shrinking */ +#define F_SEAL_GROW 0x0004 /* Prevent file from growing */ +#define F_SEAL_WRITE 0x0008 /* Prevent writes */ +#define F_SEAL_FUTURE_WRITE 0x0010 /* Prevent future writes while mapped */ + /* int creat(const char *path, mode_t mode); * * is equivalent to open with O_WRONLY|O_CREAT|O_TRUNC. diff --git a/include/sys/memfd.h b/include/sys/memfd.h new file mode 100644 index 00000000000..7bd244bf9e4 --- /dev/null +++ b/include/sys/memfd.h @@ -0,0 +1,72 @@ +/**************************************************************************** + * include/sys/memfd.h + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you 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. + * + ****************************************************************************/ + +#ifndef __INCLUDE_SYS_MEMFD_H +#define __INCLUDE_SYS_MEMFD_H + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define MFD_CLOEXEC O_CLOEXEC +#define MFD_ALLOW_SEALING (1 << 16) +#define MFD_HUGETLB (1 << 17) + +#define MFD_HUGE_SHIFT 26 +#define MFD_HUGE_MASK 0x3f +#define MFD_HUGE_64KB (16 << MFD_HUGE_SHIFT) +#define MFD_HUGE_512KB (19 << MFD_HUGE_SHIFT) +#define MFD_HUGE_1MB (20 << MFD_HUGE_SHIFT) +#define MFD_HUGE_2MB (21 << MFD_HUGE_SHIFT) +#define MFD_HUGE_8MB (23 << MFD_HUGE_SHIFT) +#define MFD_HUGE_16MB (24 << MFD_HUGE_SHIFT) +#define MFD_HUGE_32MB (25 << MFD_HUGE_SHIFT) +#define MFD_HUGE_256MB (28 << MFD_HUGE_SHIFT) +#define MFD_HUGE_512MB (29 << MFD_HUGE_SHIFT) +#define MFD_HUGE_1GB (30 << MFD_HUGE_SHIFT) +#define MFD_HUGE_2GB (31 << MFD_HUGE_SHIFT) +#define MFD_HUGE_16GB (34 << MFD_HUGE_SHIFT) + +/**************************************************************************** + * Public Function Prototypes + ****************************************************************************/ + +#ifdef __cplusplus +#define EXTERN extern "C" +extern "C" +{ +#else +#define EXTERN extern +#endif + +int memfd_create(FAR const char *name, unsigned int flags); + +#undef EXTERN +#ifdef __cplusplus +} +#endif + +#endif /* __INCLUDE_SYS_MEMFD_H */ diff --git a/libs/libc/misc/Kconfig b/libs/libc/misc/Kconfig index 8bc4e543e2e..18cde14c526 100644 --- a/libs/libc/misc/Kconfig +++ b/libs/libc/misc/Kconfig @@ -62,6 +62,13 @@ config LIBC_ENVPATH Use the contents of the common environment variable to locate executable or library files. Default: n +config MEM_FD_VFS_PATH + string "Relative path to memfd storage" + default "memfd" + depends on FS_TMPFS + ---help--- + The relative path to where memfd will exist in the tmpfs namespace. + config LIBC_ERR bool "Support err() verr() verrx() warn() vwarn() vwarnx()" default y diff --git a/libs/libc/misc/Make.defs b/libs/libc/misc/Make.defs index 3ce49fa0df9..d196ddedf96 100644 --- a/libs/libc/misc/Make.defs +++ b/libs/libc/misc/Make.defs @@ -22,7 +22,7 @@ CSRCS += lib_mknod.c lib_umask.c lib_utsname.c lib_getrandom.c CSRCS += lib_xorshift128.c lib_tea_encrypt.c lib_tea_decrypt.c -CSRCS += lib_cxx_initialize.c lib_impure.c +CSRCS += lib_cxx_initialize.c lib_impure.c lib_memfd.c # Support for platforms that do not have long long types diff --git a/libs/libc/misc/lib_memfd.c b/libs/libc/misc/lib_memfd.c new file mode 100644 index 00000000000..1f05fe5ea83 --- /dev/null +++ b/libs/libc/misc/lib_memfd.c @@ -0,0 +1,51 @@ +/**************************************************************************** + * libs/libc/misc/lib_memfd.c + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include +#include +#include +#include + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define MEM_FD_VFS_PATH CONFIG_LIBC_TMPDIR "/" CONFIG_MEM_FD_VFS_PATH "/%s" + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +int memfd_create(FAR const char *name, unsigned int flags) +{ +#ifdef CONFIG_FS_TMPFS + char path[PATH_MAX]; + + snprintf(path, sizeof(path), MEM_FD_VFS_PATH, name); + return open(path, O_RDWR | flags); +#else + set_errno(ENOSYS); + return -1; +#endif +}