Cppcheck report - Godot - branch: 3.x, commit: cd92ad0f69a842d94dc2d56f83cbd8f724ed2959 (2024-12-15): platform/x11/joypad_linux.cpp

/**************************************************************************/
/*  joypad_linux.cpp                                                      */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#ifdef JOYDEV_ENABLED

#include "joypad_linux.h"

#include "core/os/os.h"

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/input.h>
#include <unistd.h>

#ifdef UDEV_ENABLED
#include "libudev-so_wrap.h"
#endif

#define LONG_BITS (sizeof(long) * 8)
#define test_bit(nr, addr) (((1UL << ((nr) % LONG_BITS)) & ((addr)[(nr) / LONG_BITS])) != 0)
#define NBITS(x) ((((x)-1) / LONG_BITS) + 1)

#ifdef UDEV_ENABLED
static const char *ignore_str = "/dev/input/js";
#endif

JoypadLinux::Joypad::Joypad() {<--- Member variable 'Joypad::curr_axis' is not initialized in the constructor.<--- Member variable 'Joypad::key_map' is not initialized in the constructor.<--- Member variable 'Joypad::abs_map' is not initialized in the constructor.<--- Member variable 'Joypad::force_feedback' is not initialized in the constructor.<--- Member variable 'Joypad::ff_effect_id' is not initialized in the constructor.<--- Member variable 'Joypad::ff_effect_timestamp' is not initialized in the constructor.
	fd = -1;
	dpad = 0;
	devpath = "";
<--- Variable 'devpath' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'devpath' a value by passing the value to the constructor in the initialization list.
	for (int i = 0; i < MAX_ABS; i++) {
		abs_info[i] = nullptr;
	}
}

JoypadLinux::Joypad::~Joypad() {
	for (int i = 0; i < MAX_ABS; i++) {
		if (abs_info[i]) {
			memdelete(abs_info[i]);
		}
	}
}

void JoypadLinux::Joypad::reset() {
	dpad = 0;
	fd = -1;
	for (int i = 0; i < MAX_ABS; i++) {
		abs_map[i] = -1;
		curr_axis[i] = 0;
	}
	events.clear();
}

#ifdef UDEV_ENABLED
// This function is derived from SDL:
// https://github.com/libsdl-org/SDL/blob/main/src/core/linux/SDL_sandbox.c#L28-L45
static bool detect_sandbox() {
	if (access("/.flatpak-info", F_OK) == 0) {
		return true;
	}

	// For Snap, we check multiple variables because they might be set for
	// unrelated reasons. This is the same thing WebKitGTK does.
	if (OS::get_singleton()->has_environment("SNAP") && OS::get_singleton()->has_environment("SNAP_NAME") && OS::get_singleton()->has_environment("SNAP_REVISION")) {
		return true;
	}

	if (access("/run/host/container-manager", F_OK) == 0) {
		return true;
	}

	return false;
}
#endif // UDEV_ENABLED

JoypadLinux::JoypadLinux(InputDefault *in) {
#ifdef UDEV_ENABLED
	if (detect_sandbox()) {
		// Linux binaries in sandboxes / containers need special handling because
		// libudev doesn't work there. So we need to fallback to manual parsing
		// of /dev/input in such case.
		use_udev = false;
		print_verbose("JoypadLinux: udev enabled, but detected incompatible sandboxed mode. Falling back to /dev/input to detect joypads.");
	} else {
		use_udev = initialize_libudev() == 0;
		if (use_udev) {
			print_verbose("JoypadLinux: udev enabled and loaded successfully.");
		} else {
			print_verbose("JoypadLinux: udev enabled, but couldn't be loaded. Falling back to /dev/input to detect joypads.");
		}
	}
#else
	print_verbose("JoypadLinux: udev disabled, parsing /dev/input to detect joypads.");
#endif
	input = in;
	monitor_joypads_thread.start(monitor_joypads_thread_func, this);
	joypad_events_thread.start(joypad_events_thread_func, this);
}

JoypadLinux::~JoypadLinux() {
	monitor_joypads_exit.set();
	joypad_events_exit.set();
	monitor_joypads_thread.wait_to_finish();
	joypad_events_thread.wait_to_finish();
	close_joypads();
}

void JoypadLinux::monitor_joypads_thread_func(void *p_user) {
	if (p_user) {
		JoypadLinux *joy = (JoypadLinux *)p_user;
<--- C-style pointer casting [+]
C-style pointer casting detected. C++ offers four different kinds of casts as replacements: static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to any of those automatically, thus it is considered safer if the programmer explicitly states which kind of cast is expected. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.
		joy->monitor_joypads_thread_run();
	}
}

void JoypadLinux::monitor_joypads_thread_run() {
#ifdef UDEV_ENABLED
	if (use_udev) {
		udev *_udev = udev_new();
		if (!_udev) {
			use_udev = false;
			ERR_PRINT("Failed getting an udev context, falling back to parsing /dev/input.");
			monitor_joypads();
		} else {
			enumerate_joypads(_udev);
			monitor_joypads(_udev);
			udev_unref(_udev);
		}
	} else {
		monitor_joypads();
	}
#else
	monitor_joypads();
#endif
}

#ifdef UDEV_ENABLED
void JoypadLinux::enumerate_joypads(udev *p_udev) {
	udev_enumerate *enumerate;
	udev_list_entry *devices, *dev_list_entry;
	udev_device *dev;
<--- The scope of the variable 'dev' can be reduced. [+]
The scope of the variable 'dev' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.

	enumerate = udev_enumerate_new(p_udev);
	udev_enumerate_add_match_subsystem(enumerate, "input");

	udev_enumerate_scan_devices(enumerate);
	devices = udev_enumerate_get_list_entry(enumerate);
	udev_list_entry_foreach(dev_list_entry, devices) {
		const char *path = udev_list_entry_get_name(dev_list_entry);
		dev = udev_device_new_from_syspath(p_udev, path);
		const char *devnode = udev_device_get_devnode(dev);

		if (devnode) {
			String devnode_str = devnode;
			if (devnode_str.find(ignore_str) == -1) {
				open_joypad(devnode);
			}
		}
		udev_device_unref(dev);
	}
	udev_enumerate_unref(enumerate);
}

void JoypadLinux::monitor_joypads(udev *p_udev) {
	udev_device *dev = nullptr;
	udev_monitor *mon = udev_monitor_new_from_netlink(p_udev, "udev");
	udev_monitor_filter_add_match_subsystem_devtype(mon, "input", nullptr);
	udev_monitor_enable_receiving(mon);
	int fd = udev_monitor_get_fd(mon);

	while (!monitor_joypads_exit.is_set()) {
		fd_set fds;
		struct timeval tv;
		int ret;

		FD_ZERO(&fds);
		FD_SET(fd, &fds);
		tv.tv_sec = 0;
		tv.tv_usec = 0;

		ret = select(fd + 1, &fds, nullptr, nullptr, &tv);

		/* Check if our file descriptor has received data. */
		if (ret > 0 && FD_ISSET(fd, &fds)) {
			/* Make the call to receive the device.
			   select() ensured that this will not block. */
			dev = udev_monitor_receive_device(mon);

			if (dev && udev_device_get_devnode(dev) != nullptr) {
				String action = udev_device_get_action(dev);
				const char *devnode = udev_device_get_devnode(dev);
				if (devnode) {
					String devnode_str = devnode;
					if (devnode_str.find(ignore_str) == -1) {
						if (action == "add") {
							open_joypad(devnode);
						} else if (String(action) == "remove") {
							close_joypad(devnode);
						}
					}
				}
				udev_device_unref(dev);
			}
		}
		usleep(50000);
	}
	udev_monitor_unref(mon);
}
#endif

void JoypadLinux::monitor_joypads() {
	while (!monitor_joypads_exit.is_set()) {
		DIR *input_directory;
		input_directory = opendir("/dev/input");
		if (input_directory) {
			struct dirent *current;
			char fname[64];

			while ((current = readdir(input_directory)) != nullptr) {
				if (strncmp(current->d_name, "event", 5) != 0) {
					continue;
				}
				sprintf(fname, "/dev/input/%.*s", 16, current->d_name);
				if (attached_devices.find(fname) == -1) {
					open_joypad(fname);
				}
			}
		}
		closedir(input_directory);
		usleep(1000000); // 1s
	}
}

void JoypadLinux::close_joypads() {
	for (int i = 0; i < JOYPADS_MAX; i++) {
		MutexLock lock(joypads_mutex[i]);
		Joypad &joypad = joypads[i];
		close_joypad(joypad, i);
	}
}

void JoypadLinux::close_joypad(const char *p_devpath) {
	for (int i = 0; i < JOYPADS_MAX; i++) {
		MutexLock lock(joypads_mutex[i]);
		Joypad &joypad = joypads[i];
<--- The scope of the variable 'joypad' can be reduced. [+]
The scope of the variable 'joypad' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.
		if (joypads[i].devpath == p_devpath) {
			close_joypad(joypad, i);
		}
	}
}

void JoypadLinux::close_joypad(Joypad &p_joypad, int p_id) {
	if (p_joypad.fd != -1) {
		close(p_joypad.fd);
		p_joypad.fd = -1;
		attached_devices.erase(p_joypad.devpath);
		input->joy_connection_changed(p_id, false, "");
	};
	p_joypad.events.clear();
}

static String _hex_str(uint8_t p_byte) {
	static const char *dict = "0123456789abcdef";
	char ret[3];
	ret[2] = 0;

	ret[0] = dict[p_byte >> 4];
	ret[1] = dict[p_byte & 0xF];

	return ret;
}

void JoypadLinux::setup_joypad_properties(Joypad &p_joypad) {
	unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
	unsigned long absbit[NBITS(ABS_MAX)] = { 0 };

	int num_buttons = 0;
	int num_axes = 0;

	if ((ioctl(p_joypad.fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
			(ioctl(p_joypad.fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
		return;
	}
	for (int i = BTN_JOYSTICK; i < KEY_MAX; ++i) {
		if (test_bit(i, keybit)) {
			p_joypad.key_map[i] = num_buttons++;
		}
	}
	for (int i = BTN_MISC; i < BTN_JOYSTICK; ++i) {
		if (test_bit(i, keybit)) {
			p_joypad.key_map[i] = num_buttons++;
		}
	}
	for (int i = 0; i < ABS_MISC; ++i) {
		/* Skip hats */
		if (i == ABS_HAT0X) {
			i = ABS_HAT3Y;
			continue;
		}
		if (test_bit(i, absbit)) {
			p_joypad.abs_map[i] = num_axes++;
			p_joypad.abs_info[i] = memnew(input_absinfo);
			if (ioctl(p_joypad.fd, EVIOCGABS(i), p_joypad.abs_info[i]) < 0) {
				memdelete(p_joypad.abs_info[i]);
				p_joypad.abs_info[i] = nullptr;
			}
		}
	}

	p_joypad.force_feedback = false;
	p_joypad.ff_effect_timestamp = 0;
	unsigned long ffbit[NBITS(FF_CNT)];
	if (ioctl(p_joypad.fd, EVIOCGBIT(EV_FF, sizeof(ffbit)), ffbit) != -1) {
		if (test_bit(FF_RUMBLE, ffbit)) {
			p_joypad.force_feedback = true;
		}
	}
}

void JoypadLinux::open_joypad(const char *p_path) {
	int joy_num = input->get_unused_joy_id();
	int fd = open(p_path, O_RDWR | O_NONBLOCK);
	if (fd != -1 && joy_num != -1) {
		unsigned long evbit[NBITS(EV_MAX)] = { 0 };
		unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
		unsigned long absbit[NBITS(ABS_MAX)] = { 0 };

		// add to attached devices so we don't try to open it again
		attached_devices.push_back(String(p_path));

		if ((ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
				(ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
				(ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
			close(fd);
			return;
		}

		//check if the device supports basic gamepad events, prevents certain keyboards from
		//being detected as joypads
		if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
					(test_bit(ABS_X, absbit) || test_bit(ABS_Y, absbit) || test_bit(ABS_HAT0X, absbit) ||
							test_bit(ABS_GAS, absbit) || test_bit(ABS_RUDDER, absbit)) &&
					(test_bit(BTN_A, keybit) || test_bit(BTN_THUMBL, keybit) ||
							test_bit(BTN_TRIGGER, keybit) || test_bit(BTN_1, keybit))) &&
				!(test_bit(EV_ABS, evbit) &&
						test_bit(ABS_X, absbit) && test_bit(ABS_Y, absbit) &&
						test_bit(ABS_RX, absbit) && test_bit(ABS_RY, absbit))) {
			close(fd);
			return;
		}

		char uid[128];
		char namebuf[128];
		String name = "";
		input_id inpid;
		if (ioctl(fd, EVIOCGNAME(sizeof(namebuf)), namebuf) >= 0) {
			name = namebuf;
		}

		if (ioctl(fd, EVIOCGID, &inpid) < 0) {
			close(fd);
			return;
		}

		uint16_t vendor = BSWAP16(inpid.vendor);
		uint16_t product = BSWAP16(inpid.product);
		uint16_t version = BSWAP16(inpid.version);

		if (input->should_ignore_device(vendor, product)) {
			// This can be true in cases where Steam is passing information into the game to ignore
			// original gamepads when using virtual rebindings (See SteamInput).
			return;
		}

		MutexLock lock(joypads_mutex[joy_num]);
		Joypad &joypad = joypads[joy_num];
		joypad.reset();
		joypad.fd = fd;
		joypad.devpath = String(p_path);
		setup_joypad_properties(joypad);
		sprintf(uid, "%04x%04x", BSWAP16(inpid.bustype), 0);
		if (inpid.vendor && inpid.product && inpid.version) {
			sprintf(uid + String(uid).length(), "%04x%04x%04x%04x%04x%04x", vendor, 0, product, 0, version, 0);
			input->joy_connection_changed(joy_num, true, name, uid);
		} else {
			String uidname = uid;
			int uidlen = MIN(name.length(), 11);
			for (int i = 0; i < uidlen; i++) {
				uidname = uidname + _hex_str(name[i]);
			}
			uidname += "00";
			input->joy_connection_changed(joy_num, true, name, uidname);
		}
	}
}

void JoypadLinux::joypad_vibration_start(Joypad &p_joypad, float p_weak_magnitude, float p_strong_magnitude, float p_duration, uint64_t p_timestamp) {
	if (!p_joypad.force_feedback || p_joypad.fd == -1 || p_weak_magnitude < 0.f || p_weak_magnitude > 1.f || p_strong_magnitude < 0.f || p_strong_magnitude > 1.f) {
		return;
	}
	if (p_joypad.ff_effect_id != -1) {
		joypad_vibration_stop(p_joypad, p_timestamp);
	}

	struct ff_effect effect;
	effect.type = FF_RUMBLE;
	effect.id = -1;
	effect.u.rumble.weak_magnitude = floor(p_weak_magnitude * (float)0xffff);
	effect.u.rumble.strong_magnitude = floor(p_strong_magnitude * (float)0xffff);
	effect.replay.length = floor(p_duration * 1000);
	effect.replay.delay = 0;

	if (ioctl(p_joypad.fd, EVIOCSFF, &effect) < 0) {
		return;
	}

	struct input_event play;
	play.type = EV_FF;
	play.code = effect.id;
	play.value = 1;
	if (write(p_joypad.fd, (const void *)&play, sizeof(play)) == -1) {
		print_verbose("Couldn't write to Joypad device.");
	}

	p_joypad.ff_effect_id = effect.id;
	p_joypad.ff_effect_timestamp = p_timestamp;
}

void JoypadLinux::joypad_vibration_stop(Joypad &p_joypad, uint64_t p_timestamp) {
	if (!p_joypad.force_feedback || p_joypad.fd == -1 || p_joypad.ff_effect_id == -1) {
		return;
	}

	if (ioctl(p_joypad.fd, EVIOCRMFF, p_joypad.ff_effect_id) < 0) {
		return;
	}

	p_joypad.ff_effect_id = -1;
	p_joypad.ff_effect_timestamp = p_timestamp;
}

float JoypadLinux::axis_correct(const input_absinfo *p_abs, int p_value) const {
	int min = p_abs->minimum;
	int max = p_abs->maximum;
	// Convert to a value between -1.0f and 1.0f.
	return 2.0f * (p_value - min) / (max - min) - 1.0f;
}

void JoypadLinux::joypad_events_thread_func(void *p_user) {
	if (p_user) {
		JoypadLinux *joy = (JoypadLinux *)p_user;
<--- C-style pointer casting [+]
C-style pointer casting detected. C++ offers four different kinds of casts as replacements: static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to any of those automatically, thus it is considered safer if the programmer explicitly states which kind of cast is expected. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.
		joy->joypad_events_thread_run();
	}
}

void JoypadLinux::joypad_events_thread_run() {
	while (!joypad_events_exit.is_set()) {
		bool no_events = true;
		for (int i = 0; i < JOYPADS_MAX; i++) {
			MutexLock lock(joypads_mutex[i]);
			Joypad &joypad = joypads[i];
			if (joypad.fd == -1) {
				continue;
			}
			input_event event;
			while (read(joypad.fd, &event, sizeof(event)) > 0) {
				JoypadEvent joypad_event;
				joypad_event.type = event.type;
				joypad_event.code = event.code;
				joypad_event.value = event.value;
				joypad.events.push_back(joypad_event);
			}
			if (errno != EAGAIN) {
				close_joypad(joypad, i);
			}
		}
		if (no_events) {
			usleep(10000); // 10ms
		}
	}
}

void JoypadLinux::process_joypads() {
	for (int i = 0; i < JOYPADS_MAX; i++) {
		MutexLock lock(joypads_mutex[i]);
		Joypad &joypad = joypads[i];
		if (joypad.fd == -1) {
			continue;
		}
		for (uint32_t j = 0; j < joypad.events.size(); j++) {
			const JoypadEvent &joypad_event = joypad.events[j];
			// joypad_event may be tainted and out of MAX_KEY range, which will cause
			// joypad.key_map[joypad_event.code] to crash
			if (joypad_event.code >= MAX_KEY) {
				return;
			}

			switch (joypad_event.type) {
				case EV_KEY:
					input->joy_button(i, joypad.key_map[joypad_event.code], joypad_event.value);
					break;

				case EV_ABS:
					switch (joypad_event.code) {
						case ABS_HAT0X:
							if (joypad_event.value != 0) {
								if (joypad_event.value < 0) {
									joypad.dpad = (joypad.dpad | InputDefault::HAT_MASK_LEFT) & ~InputDefault::HAT_MASK_RIGHT;
								} else {
									joypad.dpad = (joypad.dpad | InputDefault::HAT_MASK_RIGHT) & ~InputDefault::HAT_MASK_LEFT;
								}
							} else {
								joypad.dpad &= ~(InputDefault::HAT_MASK_LEFT | InputDefault::HAT_MASK_RIGHT);
							}
							input->joy_hat(i, joypad.dpad);
							break;

						case ABS_HAT0Y:
							if (joypad_event.value != 0) {
								if (joypad_event.value < 0) {
									joypad.dpad = (joypad.dpad | InputDefault::HAT_MASK_UP) & ~InputDefault::HAT_MASK_DOWN;
								} else {
									joypad.dpad = (joypad.dpad | InputDefault::HAT_MASK_DOWN) & ~InputDefault::HAT_MASK_UP;
								}
							} else {
								joypad.dpad &= ~(InputDefault::HAT_MASK_UP | InputDefault::HAT_MASK_DOWN);
							}
							input->joy_hat(i, joypad.dpad);
							break;

						default:
							if (joypad_event.code >= MAX_ABS) {
								return;
							}
							if (joypad.abs_map[joypad_event.code] != -1 && joypad.abs_info[joypad_event.code]) {
								float value = axis_correct(joypad.abs_info[joypad_event.code], joypad_event.value);
								joypad.curr_axis[joypad.abs_map[joypad_event.code]] = value;
							}
							break;
					}
					break;
			}
		}
		joypad.events.clear();

		for (int j = 0; j < MAX_ABS; j++) {
			int index = joypad.abs_map[j];
			if (index != -1) {
				input->joy_axis(i, index, joypad.curr_axis[index]);
			}
		}

		if (joypad.force_feedback) {
			uint64_t timestamp = input->get_joy_vibration_timestamp(i);
			if (timestamp > joypad.ff_effect_timestamp) {
				Vector2 strength = input->get_joy_vibration_strength(i);
				float duration = input->get_joy_vibration_duration(i);
				if (strength.x == 0 && strength.y == 0) {
					joypad_vibration_stop(joypad, timestamp);
				} else {
					joypad_vibration_start(joypad, strength.x, strength.y, duration, timestamp);
				}
			}
		}
	}
}

#endif // JOYDEV_ENABLED