posix: deprecate POSIX_FS for POSIX_FILE_SYSTEM

This change deprecates CONFIG_POSIX_FS in favour of
CONFIG_POSIX_FILE_SYSTEM, which maps directly to the name of the
standard POSIX Option Group.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

doc/services/portability/posix/aep/index.rst

@@ -65,7 +65,7 @@ The *Minimal Realtime System Profile* (PSE51) includes all of the
     :ref:`_POSIX_MEMLOCK_RANGE <posix_option_memlock_range>`, -1,
     :ref:`_POSIX_MONOTONIC_CLOCK <posix_option_monotonic_clock>`, 200809L, :kconfig:option:`CONFIG_POSIX_MONOTONIC_CLOCK`
     :ref:`_POSIX_SHARED_MEMORY_OBJECTS <posix_shared_memory_objects>`, -1,
-    :ref:`_POSIX_SYNCHRONIZED_IO <posix_option_synchronized_io>`, -1,
+    :ref:`_POSIX_SYNCHRONIZED_IO <posix_option_synchronized_io>`, -1, :kconfig:option:`CONFIG_POSIX_SYNCHRONIZED_IO`
     :ref:`_POSIX_THREAD_ATTR_STACKADDR<posix_option_thread_attr_stackaddr>`, 200809L, :kconfig:option:`CONFIG_PTHREAD`
     :ref:`_POSIX_THREAD_ATTR_STACKSIZE<posix_option_thread_attr_stacksize>`, 200809L, :kconfig:option:`CONFIG_PTHREAD`
     :ref:`_POSIX_THREAD_CPUTIME <posix_option_thread_cputime>`, 200809L, :kconfig:option:`CONFIG_POSIX_CPUTIME`
@@ -103,7 +103,7 @@ The *Realtime Controller System Profile* (PSE52) includes all features from PSE5
 
     :ref:`POSIX_C_LANG_MATH <posix_option_group_c_lang_math>`, yes,
     :ref:`POSIX_FD_MGMT <posix_option_group_fd_mgmt>`,, :kconfig:option:`CONFIG_POSIX_FD_MGMT`
-    :ref:`POSIX_FILE_SYSTEM <posix_option_group_file_system>`,,
+    :ref:`POSIX_FILE_SYSTEM <posix_option_group_file_system>`,, :kconfig:option:`CONFIG_POSIX_FILE_SYSTEM`
 
 .. csv-table:: PSE52 Option Requirements
    :header: Symbol, Support, Remarks

doc/services/portability/posix/conformance/index.rst

@@ -94,7 +94,7 @@ POSIX System Interfaces
     _POSIX_SHARED_MEMORY_OBJECTS, -1,
     _POSIX_SPAWN, -1, :ref:`†<posix_undefined_behaviour>`
     _POSIX_SPORADIC_SERVER, -1, :ref:`†<posix_undefined_behaviour>`
-    _POSIX_SYNCHRONIZED_IO, -1,
+    :ref:`_POSIX_SYNCHRONIZED_IO <posix_option_synchronized_io>`, -1, :kconfig:option:`CONFIG_POSIX_SYNCHRONIZED_IO`
     :ref:`_POSIX_THREAD_ATTR_STACKADDR<posix_option_thread_attr_stackaddr>`, 200809L, :kconfig:option:`CONFIG_PTHREAD`
     :ref:`_POSIX_THREAD_ATTR_STACKSIZE<posix_option_thread_attr_stacksize>`, 200809L, :kconfig:option:`CONFIG_PTHREAD`
     :ref:`_POSIX_THREAD_CPUTIME <posix_option_thread_cputime>`, 200809L, :kconfig:option:`CONFIG_POSIX_CPUTIME`

doc/services/portability/posix/kconfig/index.rst

@@ -21,7 +21,6 @@ implementation of the POSIX API.
 * :kconfig:option:`CONFIG_NET_SOCKETS`
 * :kconfig:option:`CONFIG_NET_SOCKETS_POLL_MAX`
 * :kconfig:option:`CONFIG_POSIX_API`
-* :kconfig:option:`CONFIG_POSIX_FS`
 * :kconfig:option:`CONFIG_ZVFS_OPEN_MAX`
 * :kconfig:option:`CONFIG_POSIX_OPEN_MAX`
 * :kconfig:option:`CONFIG_POSIX_RTSIG_MAX`

include/zephyr/posix/dirent.h

@@ -9,7 +9,7 @@
 #include <limits.h>
 #include "posix_types.h"
 
-#ifdef CONFIG_POSIX_FS
+#ifdef CONFIG_POSIX_FILE_SYSTEM
 #include <zephyr/fs/fs.h>
 
 #ifdef __cplusplus
@@ -32,6 +32,6 @@ struct dirent *readdir(DIR *dirp);
 }
 #endif
 
-#endif /* CONFIG_POSIX_FS */
+#endif /* CONFIG_POSIX_FILE_SYSTEM */
 
 #endif	/* ZEPHYR_INCLUDE_POSIX_DIRENT_H_ */

lib/libc/Kconfig

@@ -107,6 +107,7 @@ config NEWLIB_LIBC
 	imply POSIX_DEVICE_IO_ALIAS_READ
 	imply POSIX_DEVICE_IO_ALIAS_WRITE
 	imply POSIX_FD_MGMT_ALIAS_LSEEK
+	imply POSIX_FILE_SYSTEM_ALIAS_FSTAT
 	help
 	  Build with newlib library. The newlib library is expected to be
 	  part of the SDK in this case.

lib/libc/newlib/libc-hooks.c

@@ -23,6 +23,7 @@
 #include <zephyr/kernel/mm.h>
 #include <sys/time.h>
 
+int _fstat(int fd, struct stat *st);
 int _read(int fd, void *buf, int nbytes);
 int _write(int fd, const void *buf, int nbytes);
 int _open(const char *name, int mode);
@@ -272,6 +273,7 @@ int _getpid(void)
 }
 __weak FUNC_ALIAS(_getpid, getpid, int);
 
+#ifndef CONFIG_POSIX_FILE_SYSTEM
 int _fstat(int file, struct stat *st)
 {
 	st->st_mode = S_IFCHR;

lib/os/fdtable.c

@@ -349,8 +349,7 @@ int zvfs_close(int fd)
 	return res;
 }
 
-#ifdef CONFIG_POSIX_FSYNC
+int zvfs_fsync(int fd)
-int fsync(int fd)
 {
 	if (_check_fd(fd) < 0) {
 		return -1;
@@ -358,8 +357,6 @@ int fsync(int fd)
 
 	return z_fdtable_call_ioctl(fdtable[fd].vtable, fdtable[fd].obj, ZFD_IOCTL_FSYNC);
 }
-FUNC_ALIAS(fsync, _fsync, int);
-#endif /* CONFIG_POSIX_FSYNC */
 
 off_t zvfs_lseek(int fd, off_t offset, int whence)
 {

lib/posix/options/CMakeLists.txt

@@ -25,8 +25,8 @@ if(CONFIG_POSIX_SIGNAL)
 endif()
 
 if(CONFIG_POSIX_API OR CONFIG_PTHREAD_IPC OR CONFIG_POSIX_TIMERS OR
-  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FS OR CONFIG_EVENTFD OR CONFIG_POSIX_C_LIB_EXT OR
+  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FILE_SYSTEM OR CONFIG_EVENTFD OR
-  CONFIG_POSIX_SINGLE_PROCESS)
+  CONFIG_POSIX_C_LIB_EXT OR CONFIG_POSIX_SINGLE_PROCESS)
   # This is a temporary workaround so that Newlib declares the appropriate
   # types for us. POSIX features to be formalized as part of #51211
   zephyr_compile_options($<$<COMPILE_LANGUAGE:C>:-D_POSIX_THREADS>)
@@ -51,7 +51,8 @@ zephyr_library_sources_ifdef(CONFIG_POSIX_DEVICE_IO
 zephyr_library_sources_ifdef(CONFIG_POSIX_FD_MGMT
   fd_mgmt.c
 )
-zephyr_library_sources_ifdef(CONFIG_POSIX_FS fs.c)
+zephyr_library_sources_ifdef(CONFIG_POSIX_FILE_SYSTEM fs.c)
+zephyr_library_sources_ifdef(CONFIG_POSIX_FSYNC fsync.c)
 zephyr_library_sources_ifdef(CONFIG_POSIX_MESSAGE_PASSING mqueue.c)
 zephyr_library_sources_ifdef(CONFIG_POSIX_MULTI_PROCESS
   sleep.c

lib/posix/options/Kconfig

@@ -44,6 +44,7 @@ rsource "Kconfig.semaphore"
 rsource "Kconfig.signal"
 rsource "Kconfig.spinlock"
 rsource "Kconfig.stropts"
+rsource "Kconfig.sync_io"
 rsource "Kconfig.syslog"
 rsource "Kconfig.timer"
 rsource "Kconfig.xsi"

lib/posix/options/Kconfig.deprecated

@@ -82,6 +82,15 @@ config POSIX_ENV
 
 	  Please use CONFIG_POSIX_SINGLE_PROCESS instead.
 
+config POSIX_FS
+	bool "Support for environ, getenv(), getenv_r(), setenv(), and unsetenv() [DEPRECATED]"
+	select DEPRECATED
+	select POSIX_FILE_SYSTEM
+	help
+	  This option is deprecated.
+
+	  Please use CONFIG_POSIX_FILE_SYSTEM instead.
+
 config POSIX_LIMITS_RTSIG_MAX
 	int "_POSIX_RTSIG_MAX value in limits.h [DEPRECATED]"
 	default POSIX_RTSIG_MAX if POSIX_REALTIME_SIGNALS

lib/posix/options/Kconfig.fs

@@ -2,20 +2,19 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-menuconfig POSIX_FS
+menuconfig POSIX_FILE_SYSTEM
 	bool "POSIX file system API support"
 	default y if POSIX_API
-	depends on FILE_SYSTEM
+	select FILE_SYSTEM
 	select FDTABLE
 	help
 	  This enables POSIX style file system related APIs.
 
-if POSIX_FS
+if POSIX_FILE_SYSTEM
 
-config POSIX_FSYNC
+config POSIX_FILE_SYSTEM_ALIAS_FSTAT
-	bool "Support for fsync()"
+	bool
-	default y
 	help
-	  This enables fsync() support.
+	  Select 'y' here and Zephyr will provide an alias for fstat() as _fstat().
 
-endif # POSIX_FS
+endif # POSIX_FILE_SYSTEM

lib/posix/options/Kconfig.sync_io

@@ -0,0 +1,39 @@
+# Copyright (c) 2024 Tenstorrent AI ULC
+#
+# SPDX-License-Identifier: Apache-2.0
+
+menu "POSIX synchronized I/O"
+
+config POSIX_FSYNC
+	bool "Support for fsync()"
+	help
+	  Select 'y' here and Zephyr will provide an implementation of fsync().
+
+	  For more information, please see
+	  https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html
+
+
+config POSIX_SYNCHRONIZED_IO
+	bool "POSIX synchronized I/O"
+	select POSIX_FSYNC
+	help
+	  Select 'y' here and Zephyr will provide an implementation of fdatasync(), fsync(),
+	  and msync().
+
+	  For more information, please see
+	  https://pubs.opengroup.org/onlinepubs/9699919799/functions/msync.html
+	  https://pubs.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html
+
+if POSIX_FSYNC
+
+# These options are intended to be used for compatibility with external POSIX
+# implementations such as those in Newlib or Picolibc.
+
+config POSIX_FILE_SYSTEM_ALIAS_FSYNC
+	bool
+	help
+	  Select 'y' here and Zephyr will provide an alias for fsync() as _fsync().
+
+endif # POSIX_FSYNC
+
+endmenu

lib/posix/options/fs.c

@@ -429,3 +429,15 @@ int zvfs_ftruncate(int fd, off_t length)
 
 	return 0;
 }
+
+int fstat(int fildes, struct stat *buf)
+{
+	ARG_UNUSED(fildes);
+	ARG_UNUSED(buf);
+
+	errno = ENOTSUP;
+	return -1;
+}
+#ifdef CONFIG_POSIX_FILE_SYSTEM_ALIAS_FSTAT
+FUNC_ALIAS(fstat, _fstat, int);
+#endif

lib/posix/options/fsync.c

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2024 Tenstorrent AI ULC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/posix/unistd.h>
+
+/* prototypes for external, not-yet-public, functions in fdtable.c */
+int zvfs_fsync(int fd);
+
+int fsync(int fd)
+{
+	return zvfs_fsync(fd);
+}
+#ifdef CONFIG_POSIX_FILE_SYSTEM_ALIAS_FSYNC
+FUNC_ALIAS(fsync, _fsync, int);
+#endif

tests/posix/fs/prj.conf

@@ -2,7 +2,7 @@ CONFIG_FILE_SYSTEM=y
 CONFIG_LOG=y
 CONFIG_FAT_FILESYSTEM_ELM=y
 CONFIG_POSIX_API=y
-CONFIG_POSIX_FS=y
+CONFIG_POSIX_FILE_SYSTEM=y
 CONFIG_ZTEST=y
 CONFIG_MAIN_STACK_SIZE=4096
 CONFIG_EVENTFD=n

tests/posix/headers/prj.conf

@@ -1,7 +1,7 @@
 CONFIG_POSIX_API=y
 CONFIG_ZTEST=y
 
-# for POSIX_FS
+# for POSIX_FILESYSTEM
 CONFIG_FILE_SYSTEM=y
 
 # for select to work
@@ -15,7 +15,7 @@ CONFIG_NET_SOCKETPAIR=y
 
 # for when CONFIG_POSIX_API is not selected
 CONFIG_PTHREAD_IPC=y
-CONFIG_POSIX_FS=y
+CONFIG_POSIX_FILE_SYSTEM=y
 CONFIG_POSIX_TIMERS=y
 CONFIG_POSIX_MESSAGE_PASSING=y
 CONFIG_EVENTFD=y