no-more-secrets-rust/src/libnms.c

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/*
* Copyright (c) 2016 Brian Barto
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the MIT License. See LICENSE for more details.
*/
/*
* DESCRIPTION
*
* The libnms library encapsulates the functuionality required to produce the
* famous "decrypting text" sceen effect from the 1992 hacker movie "Sneakers".
* For more, go to: https://github.com/bartobri/libnms
*/
#define _XOPEN_SOURCE 700
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <ctype.h>
#include <stdbool.h>
#include <time.h>
#include <locale.h>
#include <wchar.h>
#include "libnms.h"
// Color identifiers
#define COLOR_BLACK 0
#define COLOR_RED 1
#define COLOR_GREEN 2
#define COLOR_YELLOW 3
#define COLOR_BLUE 4
#define COLOR_MAGENTA 5
#define COLOR_CYAN 6
#define COLOR_WHITE 7
// Macros for VT100 codes
#define CLEAR_SCR() printf("\033[2J") // Clear Screen
#define CURSOR_HOME() printf("\033[H") // Move cursor to home position (0,0)
#define CURSOR_MOVE(x,y) printf("\033[%i;%iH", x, y) // Move cursor to x,y
#define BEEP() printf("\a"); // terminal bell
#define BOLD() printf("\033[1m") // Cursor bold
#define FOREGROUND_COLOR(x) printf("\033[3%im", x) // Set foreground color
#define CLEAR_ATTR() printf("\033[0m") // Clear bold/color attributes
#define SCREEN_SAVE() printf("\033[?47h") // Save screen display
#define SCREEN_RESTORE() printf("\033[?47l") // Restore screen to previously saved state
#define CURSOR_SAVE() printf("\033[s") // Save cursor position
#define CURSOR_RESTORE() printf("\033[u") // Restore cursor position
#define CURSOR_HIDE() printf("\033[?25l") // Hide cursor
#define CURSOR_SHOW() printf("\033[?25h") // Unhide cursor
// Program settings
#define TYPE_EFFECT_SPEED 4 // miliseconds per char
#define JUMBLE_SECONDS 2 // number of seconds for jumble effect
#define JUMBLE_LOOP_SPEED 35 // miliseconds between each jumble
#define REVEAL_LOOP_SPEED 50 // miliseconds between each reveal loop
#define MASK_CHAR_COUNT 218 // Total characters in maskCharTable[] array.
// Character attribute structure, linked list. Keeps track of every
// character's attributes required for rendering and decryption effect.
struct charAttr {
char *source;
char *mask;
int width;
int is_space;
int time;
struct charAttr *next;
};
// Static function prototypes
static void nms_sleep(int);
static int nms_term_rows(void);
static int nms_term_cols(void);
static void nms_set_terminal(int s);
static void nms_clear_input(void);
static char nms_get_char(void);
static int nms_get_cursor_row(void);
// NMS settings
static int foregroundColor = COLOR_BLUE; // Foreground color setting
static char *returnOpts = NULL; // Return option setting
static int autoDecrypt = 0; // Auto-decrypt flag
static int clearScr = 0; // clearScr flag
static int colorOn = 1; // Terminal color flag
static int inputPositionX = -1; // X coordinate for input position
static int inputPositionY = -1; // Y coordinate for input position
// Character table representing the character set know as CP437 used by
// the original IBM PC - https://en.wikipedia.org/wiki/Code_page_437
static char *maskCharTable[] = {
"!", "\"", "#", "$", "%", "&", "'", "(", ")", "*", "+", ",", "-", "~",
".", "/", ":", ";", "<", "=", ">", "?", "[", "\\", "]", "_", "{", "}",
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z",
"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m",
"n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",
"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
"\xc3\x87", "\xc3\xbc", "\xc3\xa9", "\xc3\xa2", "\xc3\xa4", "\xc3\xa0",
"\xc3\xa5", "\xc3\xa7", "\xc3\xaa", "\xc3\xab", "\xc3\xa8", "\xc3\xaf",
"\xc3\xae", "\xc3\xac", "\xc3\x84", "\xc3\x85", "\xc3\x89", "\xc3\xa6",
"\xc3\x86", "\xc3\xb4", "\xc3\xb6", "\xc3\xb2", "\xc3\xbb", "\xc3\xb9",
"\xc3\xbf", "\xc3\x96", "\xc3\x9c", "\xc2\xa2", "\xc2\xa3", "\xc2\xa5",
"\xc6\x92", "\xc3\xa1", "\xc3\xad", "\xc3\xb3", "\xc3\xba", "\xc3\xb1",
"\xc3\x91", "\xc2\xaa", "\xc2\xba", "\xc2\xbf", "\xc2\xac", "\xc2\xbd",
"\xc2\xbc", "\xc2\xa1", "\xc2\xab", "\xc2\xbb", "\xce\xb1", "\xc3\x9f",
"\xce\x93", "\xcf\x80", "\xce\xa3", "\xcf\x83", "\xc2\xb5", "\xcf\x84",
"\xce\xa6", "\xce\x98", "\xce\xa9", "\xce\xb4", "\xcf\x86", "\xce\xb5",
"\xc2\xb1", "\xc3\xb7", "\xc2\xb0", "\xc2\xb7", "\xc2\xb2", "\xc2\xb6",
"\xe2\x8c\x90", "\xe2\x82\xa7", "\xe2\x96\x91", "\xe2\x96\x92",
"\xe2\x96\x93", "\xe2\x94\x82", "\xe2\x94\xa4", "\xe2\x95\xa1",
"\xe2\x95\xa2", "\xe2\x95\x96", "\xe2\x95\x95", "\xe2\x95\xa3",
"\xe2\x95\x91", "\xe2\x95\x97", "\xe2\x95\x9d", "\xe2\x95\x9c",
"\xe2\x95\x9b", "\xe2\x94\x90", "\xe2\x94\x94", "\xe2\x94\xb4",
"\xe2\x94\xac", "\xe2\x94\x9c", "\xe2\x94\x80", "\xe2\x94\xbc",
"\xe2\x95\x9e", "\xe2\x95\x9f", "\xe2\x95\x9a", "\xe2\x95\x94",
"\xe2\x95\xa9", "\xe2\x95\xa6", "\xe2\x95\xa0", "\xe2\x95\x90",
"\xe2\x95\xac", "\xe2\x95\xa7", "\xe2\x95\xa8", "\xe2\x95\xa4",
"\xe2\x95\xa7", "\xe2\x95\x99", "\xe2\x95\x98", "\xe2\x95\x92",
"\xe2\x95\x93", "\xe2\x95\xab", "\xe2\x95\xaa", "\xe2\x94\x98",
"\xe2\x94\x8c", "\xe2\x96\x88", "\xe2\x96\x84", "\xe2\x96\x8c",
"\xe2\x96\x90", "\xe2\x96\x80", "\xe2\x88\x9e", "\xe2\x88\xa9",
"\xe2\x89\xa1", "\xe2\x89\xa5", "\xe2\x89\xa4", "\xe2\x8c\xa0",
"\xe2\x8c\xa1", "\xe2\x89\x88", "\xe2\x88\x99", "\xe2\x88\x9a",
"\xe2\x81\xbf", "\xe2\x96\xa0"
};
/*
* nms_exec() - This function is passed a pointer to a character string
* and displays the contents of the string in a way that mimicks the
* "decrypting text" effect in the 1992 movie Sneakers. It returns the
* last character pressed by the user.
*/
char nms_exec(char *string) {
struct charAttr *list_pointer = NULL;
struct charAttr *list_head = NULL;
struct charAttr *list_temp = NULL;
int i, revealed = 0;
int maxRows, maxCols, curRow, curCol, origRow = 0, origCol = 0;
char ret = 0;
// Error if we have an empty string.
if (string == NULL || string[0] == '\0') {
fprintf(stderr, "Error. Empty string.\n");
return 0;
}
// Reassociate STDIN to the terminal is needed
if (!isatty(STDIN_FILENO) && !freopen ("/dev/tty", "r", stdin)) {
fprintf(stderr, "Error. Can't associate STDIN with terminal.\n");
return 0;
}
// Turn off terminal echo and line buffering
nms_set_terminal(0);
// Needed for UTF-8 support
setlocale(LC_ALL, "");
// Get terminal window rows/cols
maxRows = nms_term_rows();
maxCols = nms_term_cols();
// Seed my random number generator with the current time
srand(time(NULL));
// Get cursor position if we are not clearing the screen
if (!clearScr) {
origRow = nms_get_cursor_row();
// nms_get_cursor_row() may display output in some terminals. So
// we need to reposition the cursor to the start of the row.
CURSOR_MOVE(origRow, origCol);
}
// Assign current row/col positions
curRow = origRow;
curCol = origCol;
// Geting input
for (i = 0; string[i] != '\0'; ++i) {
// Don't go beyond maxRows
if (curRow - origRow >= maxRows - 1) {
break;
}
// Allocate memory for next list link
if (list_pointer == NULL) {
list_pointer = malloc(sizeof(struct charAttr));
list_head = list_pointer;
} else {
list_pointer->next = malloc(sizeof(struct charAttr));
list_pointer = list_pointer->next;
}
// Get character's byte-length and store character.
if (mblen(&string[i], 4) > 0) {
list_pointer->source = malloc(mblen(&string[i], 4) + 1);
strncpy(list_pointer->source, &string[i], mblen(&string[i], 4));
list_pointer->source[mblen(&string[i], 4)] = '\0';
i += (mblen(&string[i], 4) - 1);
} else {
fprintf(stderr, "Unknown character encountered. Quitting.\n");
nms_set_terminal(1);
return 0;
}
// Set flag if we have a whitespace character
if (strlen(list_pointer->source) == 1 && isspace(list_pointer->source[0]))
list_pointer->is_space = 1;
else
list_pointer->is_space = 0;
// Set initial mask chharacter
list_pointer->mask = maskCharTable[rand() % MASK_CHAR_COUNT];
// Set reveal time
list_pointer->time = rand() % 5000;
// Set character column width
wchar_t widec[sizeof(list_pointer->source)] = {};
mbstowcs(widec, list_pointer->source, sizeof(list_pointer->source));
list_pointer->width = wcwidth(*widec);
// Set next node to null
list_pointer->next = NULL;
// Track row count
if (string[i] == '\n' || (curCol += list_pointer->width) > maxCols) {
curCol = 0;
curRow++;
if (curRow == maxRows + 1 && origRow > 0) {
origRow--;
curRow--;
}
}
}
// Save terminal state, clear screen, and home/hide the cursor
if (clearScr) {
CURSOR_SAVE();
SCREEN_SAVE();
CLEAR_SCR();
CURSOR_HOME();
CURSOR_HIDE();
}
// Print mask characters with 'type effect'
for (list_pointer = list_head; list_pointer != NULL; list_pointer = list_pointer->next) {
// Print mask character (or space)
if (list_pointer->is_space) {
printf("%s", list_pointer->source);
continue;
}
// print mask character
printf("%s", list_pointer->mask);
if (list_pointer->width == 2) {
printf("%s", maskCharTable[rand() % MASK_CHAR_COUNT]);
}
// flush output and sleep
fflush(stdout);
nms_sleep(TYPE_EFFECT_SPEED);
}
// Flush any input up to this point
nms_clear_input();
// If autoDecrypt flag is set, we sleep. Otherwise require user to
// press a key to continue.
if (autoDecrypt)
sleep(1);
else
nms_get_char();
// Jumble loop
for (i = 0; i < (JUMBLE_SECONDS * 1000) / JUMBLE_LOOP_SPEED; ++i) {
// Move cursor to home position
if (clearScr) {
CURSOR_HOME();
} else {
CURSOR_MOVE(origRow, origCol);
}
// Print new mask for all characters
for (list_pointer = list_head; list_pointer != NULL; list_pointer = list_pointer->next) {
// Print mask character (or space)
if (list_pointer->is_space) {
printf("%s", list_pointer->source);
continue;
}
// print new mask character
printf("%s", maskCharTable[rand() % MASK_CHAR_COUNT]);
if (list_pointer->width == 2) {
printf("%s", maskCharTable[rand() % MASK_CHAR_COUNT]);
}
}
// flush output and sleep
fflush(stdout);
nms_sleep(JUMBLE_LOOP_SPEED);
}
// Reveal loop
while (!revealed) {
// Move cursor to home position
if (clearScr) {
CURSOR_HOME();
} else {
CURSOR_MOVE(origRow, origCol);
}
// Set revealed flag
revealed = 1;
for (list_pointer = list_head; list_pointer != NULL; list_pointer = list_pointer->next) {
// Print mask character (or space)
if (list_pointer->is_space) {
printf("%s", list_pointer->source);
continue;
}
// If we still have time before the char is revealed, display the mask
if (list_pointer->time > 0) {
// Change the mask randomly
if (list_pointer->time < 500) {
if (rand() % 3 == 0) {
list_pointer->mask = maskCharTable[rand() % MASK_CHAR_COUNT];
}
} else {
if (rand() % 10 == 0) {
list_pointer->mask = maskCharTable[rand() % MASK_CHAR_COUNT];
}
}
// Print mask
printf("%s", list_pointer->mask);
// Decrement reveal time
list_pointer->time -= REVEAL_LOOP_SPEED;
// Unset revealed flag
revealed = 0;
} else {
// Set bold and foreground color for character reveal
BOLD();
if (colorOn) {
FOREGROUND_COLOR(foregroundColor);
}
// print source character
printf("%s", list_pointer->source);
// Unset foreground color
CLEAR_ATTR();
}
}
// flush output and sleep
fflush(stdout);
nms_sleep(REVEAL_LOOP_SPEED);
}
// Flush any input up to this point
nms_clear_input();
if (clearScr) {
// Position cursor
if (inputPositionY >= 0 && inputPositionX >= 0) {
CURSOR_MOVE(inputPositionY, inputPositionX);
CURSOR_SHOW();
}
// User must press a key to continue
ret = nms_get_char();
if (returnOpts != NULL && strlen(returnOpts) > 0) {
while (strchr(returnOpts, ret) == NULL) {
BEEP();
ret = nms_get_char();
}
}
// Restore screen and cursor
SCREEN_RESTORE();
CURSOR_SHOW();
CURSOR_RESTORE();
}
// Turn on terminal echo and line buffering
nms_set_terminal(1);
// Freeing the list.
list_pointer = list_head;
while (list_pointer != NULL) {
list_temp = list_pointer;
list_pointer = list_pointer->next;
free(list_temp->source);
free(list_temp);
}
return ret;
}
/*
* nms_set_foreground_color() sets the foreground color of the unencrypted
* characters as they are revealed to the color indicated by the 'color'
* argument. Valid arguments are "white", "yellow", "magenta", "blue",
* "green", "red", and "cyan". This function will default to blue if
* passed an invalid color. No value is returned.
*/
void nms_set_foreground_color(char *color) {
if(strcmp("white", color) == 0)
foregroundColor = COLOR_WHITE;
else if(strcmp("yellow", color) == 0)
foregroundColor = COLOR_YELLOW;
else if(strcmp("black", color) == 0)
foregroundColor = COLOR_BLACK;
else if(strcmp("magenta", color) == 0)
foregroundColor = COLOR_MAGENTA;
else if(strcmp("blue", color) == 0)
foregroundColor = COLOR_BLUE;
else if(strcmp("green", color) == 0)
foregroundColor = COLOR_GREEN;
else if(strcmp("red", color) == 0)
foregroundColor = COLOR_RED;
else if(strcmp("cyan", color) == 0)
foregroundColor = COLOR_CYAN;
else
foregroundColor = COLOR_BLUE;
}
/*
* nms_set_return_opts() takes a character sting and copies it to the
* returnOpts setting used by nms_exec().
*/
void nms_set_return_opts(char *opts) {
returnOpts = realloc(returnOpts, strlen(opts) + 1);
strcpy(returnOpts, opts);
}
/*
* nms_set_auto_decrypt() sets the autoDecrypt flag according to the
* true/false value of the 'setting' argument.
*/
void nms_set_auto_decrypt(int setting) {
if (setting)
autoDecrypt = 1;
else
autoDecrypt = 0;
}
/*
* nms_set_clear_scr() sets the clearScr flag according to the
* true/false value of the 'setting' argument.
*/
void nms_set_clear_scr(int setting) {
if (setting)
clearScr = 1;
else
clearScr = 0;
}
/*
* nms_set_color() sets the colorOn flag according to the
* true/false value of the 'setting' argument.
*/
void nms_use_color(int setting) {
if (setting)
colorOn = 1;
else
colorOn = 0;
}
/*
* nms_set_input_position() sets the desired coordinate of the cursor in
* the terminal when accepting user input after nms_exec() reveals the
* unencrypted characters.
*/
void nms_set_input_position(int x, int y) {
if (x >= 0 && y >= 0) {
inputPositionX = x;
inputPositionY = y;
}
}
/*
* nms_sleep() sleeps for the number of miliseconds indicated by 't'.
*/
static void nms_sleep(int t) {
struct timespec ts;
ts.tv_sec = t / 1000;
ts.tv_nsec = (t % 1000) * 1000000;
nanosleep(&ts, NULL);
}
/*
* nms_term_rows() gets and returns the number of rows in the current
* terminal window.
*/
static int nms_term_rows(void) {
struct winsize w;
ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
return w.ws_row;
}
/*
* nms_term_cols() gets and returns the number of cols in the current
* terminal window.
*/
static int nms_term_cols(void) {
struct winsize w;
ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
return w.ws_col;
}
/*
* nms_set_terminal() turns off terminal echo and line buffering when
* passed an integer value that evaluates to true. It restores the
* original terminal values when passed an integer value that evaluates
* to false.
*/
static void nms_set_terminal(int s) {
struct termios tp;
static struct termios save;
static int state = 1;
if (s == 0) {
if (tcgetattr(STDIN_FILENO, &tp) == -1) {
return;
}
save = tp;
tp.c_lflag &=(~ICANON & ~ECHO);
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tp) == -1) {
return;
}
} else {
if (state == 0 && tcsetattr(STDIN_FILENO, TCSANOW, &save) == -1)
return;
}
state = s;
}
/*
* nms_clear_input() clears the input buffer of all characters up to
* the EOF character.
*/
static void nms_clear_input(void) {
int i;
ioctl(STDIN_FILENO, FIONREAD, &i);
while (i > 0) {
getchar();
--i;
}
}
/*
* nms_get_char() returns the next character in the input buffer. In the
* case of an EOF character, it blocks until the user presses a key.
*/
static char nms_get_char(void) {
struct timespec ts;
int t = 50;
char c;
ts.tv_sec = t / 1000;
ts.tv_nsec = (t % 1000) * 1000000;
while ((c = getchar()) == EOF) {
nanosleep(&ts, NULL);
}
return c;
}
/*
* nms_get_cursor_row() returns the row position of the cursor as reported
* by the terminal program via the ANSI escape code
*/
static int nms_get_cursor_row(void) {
int i, r = 0;
int row = 0;
char buf[10];
char *cmd = "\033[6n";
memset(buf, 0, sizeof(buf));
write(STDOUT_FILENO, cmd, sizeof(cmd));
r = read(STDIN_FILENO, buf, sizeof(buf));
for (i = 0; i < r; ++i) {
if (buf[i] == 27 || buf[i] == '[') {
continue;
}
if (buf[i] >= '0' && buf[i] <= '9') {
row = (row * 10) + (buf[i] - '0');
}
if (buf[i] == ';' || buf[i] == 'R' || buf[i] == 0) {
break;
}
}
return row;
}