Unix: Remove now unnecessary I/O defines, cleanup

- `LIBC_FILEIO_ENABLED` wasn't defined anywhere, even in _other platforms_.
- `NO_NETWORK` is also never defined. It probably isn't enough anyway to
  disable network APIs in the current codebase.
- `UNIX_SOCKET_UNAVAILABLE` is never defined in this code but used by some
  other platforms, clarify that.
- `NO_STATVFS` can be removed as Android supports it since API level 19,
  which is our current min SDK level. It's also only used for
  `DirAccessUnix::get_space_left()` which is anyway overridden by
  `DirAccessJAndroid::get_space_left()` so it shouldn't make a difference.
  * Fixed documentation for `DirAccess.get_space_left()`.
- `NO_FCNTL` is likely also a remnant of early Android days, in current NDK
  r23 it seems to be available. Also cleaned up unused `fcntl.h` includes.
- `NO_ALLOCA` is never defined, and we use alloca in many places now.

7 files changed, 23 insertions, 53 deletions

diff --git a/drivers/unix/dir_access_unix.cpp b/drivers/unix/dir_access_unix.cpp
index 55ea952696..c25ceba44d 100644
--- a/drivers/unix/dir_access_unix.cpp
+++ b/drivers/unix/dir_access_unix.cpp
@@ -30,7 +30,7 @@
 
 #include "dir_access_unix.h"
 
-#if defined(UNIX_ENABLED) || defined(LIBC_FILEIO_ENABLED)
+#if defined(UNIX_ENABLED)
 
 #include "core/os/memory.h"
 #include "core/os/os.h"
@@ -41,10 +41,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-
-#ifndef ANDROID_ENABLED
 #include <sys/statvfs.h>
-#endif
 
 #ifdef HAVE_MNTENT
 #include <mntent.h>
@@ -475,17 +472,12 @@ Error DirAccessUnix::create_link(String p_source, String p_target) {
 }
 
 uint64_t DirAccessUnix::get_space_left() {
-#ifndef NO_STATVFS
 	struct statvfs vfs;
 	if (statvfs(current_dir.utf8().get_data(), &vfs) != 0) {
 		return 0;
 	}
 
 	return (uint64_t)vfs.f_bavail * (uint64_t)vfs.f_frsize;
-#else
-	// FIXME: Implement this.
-	return 0;
-#endif
 }
 
 String DirAccessUnix::get_filesystem_type() const {
@@ -516,4 +508,4 @@ DirAccessUnix::~DirAccessUnix() {
 	list_dir_end();
 }
 
-#endif // UNIX_ENABLED || LIBC_FILEIO_ENABLED
+#endif // UNIX_ENABLED
diff --git a/drivers/unix/dir_access_unix.h b/drivers/unix/dir_access_unix.h
index f5dca7c282..4db24a27b9 100644
--- a/drivers/unix/dir_access_unix.h
+++ b/drivers/unix/dir_access_unix.h
@@ -31,7 +31,7 @@
 #ifndef DIR_ACCESS_UNIX_H
 #define DIR_ACCESS_UNIX_H
 
-#if defined(UNIX_ENABLED) || defined(LIBC_FILEIO_ENABLED)
+#if defined(UNIX_ENABLED)
 
 #include "core/io/dir_access.h"
 
@@ -90,6 +90,6 @@ public:
 	~DirAccessUnix();
 };
 
-#endif // UNIX_ENABLED || LIBC_FILEIO_ENABLED
+#endif // UNIX_ENABLED
 
 #endif // DIR_ACCESS_UNIX_H
diff --git a/drivers/unix/file_access_unix.cpp b/drivers/unix/file_access_unix.cpp
index 300fbcdcfd..0df645c4e5 100644
--- a/drivers/unix/file_access_unix.cpp
+++ b/drivers/unix/file_access_unix.cpp
@@ -30,24 +30,20 @@
 
 #include "file_access_unix.h"
 
-#if defined(UNIX_ENABLED) || defined(LIBC_FILEIO_ENABLED)
+#if defined(UNIX_ENABLED)
 
 #include "core/os/os.h"
 #include "core/string/print_string.h"
 
+#include <errno.h>
+#include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include <errno.h>
-
 #if defined(UNIX_ENABLED)
 #include <unistd.h>
 #endif
 
-#ifndef ANDROID_ENABLED
-#include <sys/statvfs.h>
-#endif
-
 #ifdef MSVC
 #define S_ISREG(m) ((m)&_S_IFREG)
 #include <io.h>
@@ -56,12 +52,6 @@
 #define S_ISREG(m) ((m)&S_IFREG)
 #endif
 
-#ifndef NO_FCNTL
-#include <fcntl.h>
-#else
-#include <sys/ioctl.h>
-#endif
-
 void FileAccessUnix::check_errors() const {
 	ERR_FAIL_COND_MSG(!f, "File must be opened before use.");
 
@@ -131,13 +121,8 @@ Error FileAccessUnix::open_internal(const String &p_path, int p_mode_flags) {
 	int fd = fileno(f);
 
 	if (fd != -1) {
-#if defined(NO_FCNTL)
-		unsigned long par = 0;
-		ioctl(fd, FIOCLEX, &par);
-#else
 		int opts = fcntl(fd, F_GETFD);
 		fcntl(fd, F_SETFD, opts | FD_CLOEXEC);
-#endif
 	}
 
 	last_error = OK;
@@ -339,4 +324,4 @@ FileAccessUnix::~FileAccessUnix() {
 	_close();
 }
 
-#endif // UNIX_ENABLED || LIBC_FILEIO_ENABLED
+#endif // UNIX_ENABLED
diff --git a/drivers/unix/file_access_unix.h b/drivers/unix/file_access_unix.h
index e1311a80f8..8c9afe75e7 100644
--- a/drivers/unix/file_access_unix.h
+++ b/drivers/unix/file_access_unix.h
@@ -36,7 +36,7 @@
 
 #include <stdio.h>
 
-#if defined(UNIX_ENABLED) || defined(LIBC_FILEIO_ENABLED)
+#if defined(UNIX_ENABLED)
 
 typedef void (*CloseNotificationFunc)(const String &p_file, int p_flags);
 
@@ -86,6 +86,6 @@ public:
 	virtual ~FileAccessUnix();
 };
 
-#endif // UNIX_ENABLED || LIBC_FILEIO_ENABLED
+#endif // UNIX_ENABLED
 
 #endif // FILE_ACCESS_UNIX_H
diff --git a/drivers/unix/net_socket_posix.cpp b/drivers/unix/net_socket_posix.cpp
index 86adf33d62..72ae609fb4 100644
--- a/drivers/unix/net_socket_posix.cpp
+++ b/drivers/unix/net_socket_posix.cpp
@@ -30,32 +30,30 @@
 
 #include "net_socket_posix.h"
 
+// Some proprietary Unix-derived platforms don't expose Unix sockets
+// so this allows skipping this file to reimplement this API differently.
 #ifndef UNIX_SOCKET_UNAVAILABLE
+
 #if defined(UNIX_ENABLED)
 
 #include <errno.h>
+#include <fcntl.h>
 #include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
+#include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>
-#ifndef NO_FCNTL
-#include <fcntl.h>
-#else
-#include <sys/ioctl.h>
-#endif
-#include <netinet/in.h>
 
-#include <sys/socket.h>
 #ifdef WEB_ENABLED
 #include <arpa/inet.h>
 #endif
 
-#include <netinet/tcp.h>
-
 // BSD calls this flag IPV6_JOIN_GROUP
 #if !defined(IPV6_ADD_MEMBERSHIP) && defined(IPV6_JOIN_GROUP)
 #define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
@@ -93,7 +91,7 @@
 #define SIO_UDP_NETRESET _WSAIOW(IOC_VENDOR, 15)
 #endif
 
-#endif
+#endif // UNIX_ENABLED
 
 size_t NetSocketPosix::_set_addr_storage(struct sockaddr_storage *p_addr, const IPAddress &p_ip, uint16_t p_port, IP::Type p_ip_type) {
 	memset(p_addr, 0, sizeof(struct sockaddr_storage));
@@ -309,14 +307,9 @@ void NetSocketPosix::_set_socket(SOCKET_TYPE p_sock, IP::Type p_ip_type, bool p_
 void NetSocketPosix::_set_close_exec_enabled(bool p_enabled) {
 #ifndef WINDOWS_ENABLED
 	// Enable close on exec to avoid sharing with subprocesses. Off by default on Windows.
-#if defined(NO_FCNTL)
-	unsigned long par = p_enabled ? 1 : 0;
-	SOCK_IOCTL(_sock, FIOCLEX, &par);
-#else
 	int opts = fcntl(_sock, F_GETFD);
 	fcntl(_sock, F_SETFD, opts | FD_CLOEXEC);
 #endif
-#endif
 }
 
 Error NetSocketPosix::open(Type p_sock_type, IP::Type &ip_type) {
@@ -658,7 +651,7 @@ void NetSocketPosix::set_blocking_enabled(bool p_enabled) {
 	ERR_FAIL_COND(!is_open());
 
 	int ret = 0;
-#if defined(WINDOWS_ENABLED) || defined(NO_FCNTL)
+#if defined(WINDOWS_ENABLED)
 	unsigned long par = p_enabled ? 0 : 1;
 	ret = SOCK_IOCTL(_sock, FIONBIO, &par);
 #else
@@ -781,4 +774,5 @@ Error NetSocketPosix::join_multicast_group(const IPAddress &p_multi_address, Str
 Error NetSocketPosix::leave_multicast_group(const IPAddress &p_multi_address, String p_if_name) {
 	return _change_multicast_group(p_multi_address, p_if_name, false);
 }
-#endif
+
+#endif // UNIX_SOCKET_UNAVAILABLE
diff --git a/drivers/unix/os_unix.cpp b/drivers/unix/os_unix.cpp
index c8a42e925e..0c85b7503f 100644
--- a/drivers/unix/os_unix.cpp
+++ b/drivers/unix/os_unix.cpp
@@ -137,10 +137,8 @@ void OS_Unix::initialize_core() {
 	DirAccess::make_default<DirAccessUnix>(DirAccess::ACCESS_USERDATA);
 	DirAccess::make_default<DirAccessUnix>(DirAccess::ACCESS_FILESYSTEM);
 
-#ifndef NO_NETWORK
 	NetSocketPosix::make_default();
 	IPUnix::make_default();
-#endif
 
 	_setup_clock();
 }
@@ -170,6 +168,7 @@ Error OS_Unix::get_entropy(uint8_t *r_buffer, int p_bytes) {
 		left -= chunk;
 		ofs += chunk;
 	} while (left > 0);
+// Define this yourself if you don't want to fall back to /dev/urandom.
 #elif !defined(NO_URANDOM)
 	int r = open("/dev/urandom", O_RDONLY);
 	ERR_FAIL_COND_V(r < 0, FAILED);
diff --git a/drivers/unix/os_unix.h b/drivers/unix/os_unix.h
index b35f161524..ce81ca0aca 100644
--- a/drivers/unix/os_unix.h
+++ b/drivers/unix/os_unix.h
@@ -53,7 +53,7 @@ public:
 
 	virtual String get_stdin_string(bool p_block) override;
 
-	virtual Error get_entropy(uint8_t *r_buffer, int p_bytes) override; // Should return cryptographycally-safe random bytes.
+	virtual Error get_entropy(uint8_t *r_buffer, int p_bytes) override;
 
 	virtual Error open_dynamic_library(const String p_path, void *&p_library_handle, bool p_also_set_library_path = false, String *r_resolved_path = nullptr) override;
 	virtual Error close_dynamic_library(void *p_library_handle) override;