lib: posix: Use more fine-grained and orthogonal Kconfig options

Basic requirements:
1. It should be possible to control whether include/posix/ is
added to include search path or not.
2. It should be possible to use individual parts of POSIX API,
without bringing in everything else. For example, if user is
interested in just sleep(), should be possible to enable just
that.
3. Keep existing CONFIG_POSIX_API as "master switch", which
enables "a lot of POSIX APIs".

Fixes: zephyrproject-rtos#12965

Signed-off-by: Paul Sokolovsky <[email protected]>

Author: pfalcon

lib/CMakeLists.txt

@@ -1,7 +1,7 @@
 if(NOT CONFIG_NATIVE_APPLICATION)
 add_subdirectory(libc)
 endif()
-add_subdirectory_ifdef(CONFIG_POSIX_API            posix)
+add_subdirectory(posix)
 add_subdirectory_ifdef(CONFIG_CMSIS_RTOS_V1        cmsis_rtos_v1)
 add_subdirectory_ifdef(CONFIG_CMSIS_RTOS_V2        cmsis_rtos_v2)
 add_subdirectory(gui)

lib/posix/CMakeLists.txt

@@ -1,7 +1,9 @@
 
 add_library(PTHREAD INTERFACE)
 
-target_include_directories(PTHREAD INTERFACE ${ZEPHYR_BASE}/include/posix)
+if(CONFIG_POSIX_HEADERS)
+zephyr_include_directories(${ZEPHYR_BASE}/include/posix)
+endif()
 
 zephyr_library()
 zephyr_library_sources(pthread_common.c)
@@ -11,7 +13,7 @@ zephyr_library_sources_ifdef(CONFIG_PTHREAD_IPC pthread_barrier.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_IPC pthread.c)
 zephyr_library_sources(pthread_sched.c)
 zephyr_library_sources(clock.c)
-zephyr_library_sources(sleep.c)
+zephyr_library_sources_ifdef(CONFIG_POSIX_SLEEP sleep.c)
 zephyr_library_sources(timer.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_IPC pthread_rwlock.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_IPC semaphore.c)

lib/posix/Kconfig

@@ -15,11 +15,24 @@ config	POSIX_MAX_FDS
 config POSIX_API
 	depends on !ARCH_POSIX
 	bool "POSIX APIs"
+	select POSIX_HEADERS
+	select POSIX_SLEEP
 	help
 	  Enable mostly-standards-compliant implementations of
 	  various POSIX (IEEE 1003.1) APIs.
 
-if POSIX_API
+config POSIX_HEADERS
+	bool "Make available POSIX headers"
+	help
+	  If enabled, applications will be able to include <unistd.h>,
+	  <sys/socket.h> and all other POSIX headers under their native
+	  names. If disabled, all the headers are still available, with
+	  "posix/" prefix, e.g. <posix/unistd.h>.
+
+config POSIX_SLEEP
+	bool "POSIX sleep()/usleep() calls"
+	help
+	  Provide sleep()/usleep() calls.
 
 config PTHREAD_IPC
 	bool "POSIX pthread IPC API"
@@ -95,5 +108,3 @@ config	POSIX_MAX_OPEN_FILES
 	  is additionally bounded by CONFIG_POSIX_MAX_FDS.
 endif
 endif # FILE_SYSTEM
-
-endif # POSIX_API