posix: remove zephyr/posix in header prefixes

If C libraries provide conformant POSIX headers, then use the headers
provided by the C library.

Otherwise, C library maintainers may add `include/zephyr/posix` to their
standard search path.

This change removes the requirement to have `<zephyr/posix/...>` prefixing
all standard POSIX includes in Zephyr.

The main reason that it was required was due to conflicts between C
library time.h, signal.h and the fact that Zephyr posix headers were being
somewhat ad-hoc mixed with libc posix headers.

Now, any (even partially) POSIX-conformant C libraries are expected to
provide their own types, constants, and headers, and Zephyr's
implementation uses those definitions.

If any definitions are missing, we define them on a per-libc basis. This
can also be done out-of-tree, which allows for implementors to take
advantage of the `CONFIG_TC_PROVIDES_POSIX..` options.

This is likely the last major commit required before we deprecate the
`CONFIG_POSIX_API` Kconfig option in favour of POSIX subprofiling \o/

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

Author: cfriedt

drivers/modem/ublox-sara-r4.c

@@ -15,7 +15,7 @@ LOG_MODULE_REGISTER(modem_ublox_sara_r4, CONFIG_MODEM_LOG_LEVEL);
 #include <zephyr/drivers/gpio.h>
 #include <zephyr/device.h>
 #include <zephyr/init.h>
-#include <zephyr/posix/fcntl.h>
+#include <fcntl.h>
 
 #include <zephyr/net/net_if.h>
 #include <zephyr/net/net_offload.h>

drivers/net/nsos_fcntl.c

@@ -19,11 +19,7 @@
 /*
  * When building for Zephyr, use Zephyr specific fcntl definitions.
  */
-#ifdef __ZEPHYR__
-#include <zephyr/posix/fcntl.h>
-#else
 #include <fcntl.h>
-#endif
 
 #include "nsi_errno.h"
 #include "nsos_fcntl.h"

drivers/net/nsos_sockets.c

@@ -24,7 +24,7 @@ LOG_MODULE_REGISTER(nsos_sockets);
 #include <zephyr/net/net_ip.h>
 #include <zephyr/net/offloaded_netdev.h>
 #include <zephyr/net/socket_offload.h>
-#include <zephyr/posix/fcntl.h>
+#include <fcntl.h>
 #include <zephyr/sys/fdtable.h>
 #include <zephyr/sys/dlist.h>
 

drivers/net/ppp.c

@@ -26,12 +26,12 @@ LOG_MODULE_REGISTER(net_ppp, LOG_LEVEL);
 #include <zephyr/net_buf.h>
 #include <zephyr/net/net_pkt.h>
 #include <zephyr/net/net_if.h>
+#include <zephyr/net/if_arp.h>
 #include <zephyr/net/net_core.h>
 #include <zephyr/sys/ring_buffer.h>
 #include <zephyr/sys/crc.h>
 #include <zephyr/drivers/uart.h>
 #include <zephyr/random/random.h>
-#include <zephyr/posix/net/if_arp.h>
 #include <zephyr/net/ethernet.h>
 #include <zephyr/net/capture.h>
 

drivers/wifi/simplelink/CMakeLists.txt

@@ -9,5 +9,7 @@ if(CONFIG_WIFI_SIMPLELINK)
     simplelink_support.c
     simplelink.c
     )
+  # TI's driver portability layer relies on POSIX for multi-threading and timers
+  zephyr_library_compile_definitions(_POSIX_C_SOURCE=200809L)
 endif()
 zephyr_library_sources_ifdef(CONFIG_NET_SOCKETS_OFFLOAD simplelink_sockets.c)

drivers/wifi/simplelink/Kconfig.simplelink

@@ -9,7 +9,9 @@ menuconfig WIFI_SIMPLELINK
 	select WIFI_OFFLOAD
 	select NET_L2_WIFI_MGMT
 	select FDTABLE
-	select POSIX_SEMAPHORES
+	# TI's driver portability layer relies on POSIX for multi-threading and timers
+	select POSIX_BASE_DEFINITIONS
+	select POSIX_SYSTEM_INTERFACES
 
 if WIFI_SIMPLELINK
 

drivers/wifi/simplelink/simplelink_sockets.c

@@ -9,7 +9,7 @@ LOG_MODULE_DECLARE(LOG_MODULE_NAME);
 
 #include <stdlib.h>
 #include <limits.h>
-#include <zephyr/posix/fcntl.h>
+#include <fcntl.h>
 
 #include <zephyr/kernel.h>
 /* Define sockaddr, etc, before simplelink.h */

include/zephyr/net/ethernet.h

@@ -18,8 +18,6 @@
 #include <stdbool.h>
 #include <zephyr/sys/atomic.h>
 
-#include <zephyr/net/net_ip.h>
-#include <zephyr/net/net_pkt.h>
 #include <zephyr/net/lldp.h>
 #include <zephyr/sys/util.h>
 #include <zephyr/net/net_if.h>

include/zephyr/posix/net/if_arp.h renamed to include/zephyr/net/if_arp.h

@@ -1280,19 +1280,19 @@ struct socket_op_vtable {
  */
 #if defined(CONFIG_POSIX_API)
 #if !defined(ZEPHYR_INCLUDE_POSIX_ARPA_INET_H_)
-#include <zephyr/posix/arpa/inet.h>
+#include <arpa/inet.h>
 #endif
 #if !defined(ZEPHYR_INCLUDE_POSIX_NETDB_H_)
-#include <zephyr/posix/netdb.h>
+#include <netdb.h>
 #endif
 #if !defined(ZEPHYR_INCLUDE_POSIX_UNISTD_H_)
-#include <zephyr/posix/unistd.h>
+#include <unistd.h>
 #endif
 #if !defined(ZEPHYR_INCLUDE_POSIX_POLL_H_)
-#include <zephyr/posix/poll.h>
+#include <poll.h>
 #endif
 #if !defined(ZEPHYR_INCLUDE_POSIX_SYS_SOCKET_H_)
-#include <zephyr/posix/sys/socket.h>
+#include <sys/socket.h>
 #endif
 #endif /* CONFIG_POSIX_API */