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-rw-r--r--src/nyancat.c344
1 files changed, 196 insertions, 148 deletions
diff --git a/src/nyancat.c b/src/nyancat.c
index 33f8522..1bc0294 100644
--- a/src/nyancat.c
+++ b/src/nyancat.c
@@ -59,6 +59,7 @@
#include <time.h>
#include <setjmp.h>
#include <sys/ioctl.h>
+#include <getopt.h>
#ifndef TIOCGWINSZ
#include <termios.h>
@@ -236,6 +237,17 @@ void send_command(int cmd, int opt) {
}
}
+void usage(char * argv[]) {
+ printf(
+ "Terminal Nyancat\n"
+ "\n"
+ "usage: %s [-h] [-t] [-i] \n"
+ "\n"
+ " -i --intro \033[3mShow the introduction / about informaiton at startup.\033[0m\n"
+ " -t --telnet \033[3mTelnet mode.\033[0m\n",
+ " -h --help \033[3mShow this help message.\033[0m\n",
+ argv[0]);
+}
int main(int argc, char ** argv) {
@@ -249,126 +261,160 @@ int main(int argc, char ** argv) {
char sb[1024] = {0};
char sb_len = 0;
- if (argc > 1) {
- if (!strcmp(argv[1], "-t")) {
- /* Yes, I know, lame way to get arguments, whatever, we only want one of them. */
- telnet = 1;
+ char show_intro = 0;
+
+ /* Long option names */
+ static struct option long_opts[] = {
+ {"help", no_argument, 0, 'h'},
+ {"telnet", no_argument, 0, 't'},
+ {"intro", no_argument, 0, 'i'},
+ {0,0,0,0}
+ };
+
+ /* Process arguments */
+ int index, c;
+ while ((c = getopt_long(argc, argv, "hit", long_opts, &index)) != -1) {
+ if (!c) {
+ if (long_opts[index].flag == 0) {
+ c = long_opts[index].val;
+ }
+ }
+ switch (c) {
+ case 'i': /* Show introduction */
+ show_intro = 1;
+ break;
+ case 't': /* Expect telnet bits */
+ telnet = 1;
+ break;
+ case 'h': /* Show help and exit */
+ usage(argv);
+ exit(0);
+ break;
+ default:
+ break;
+ }
+ }
- /* Set the default options */
- set_options();
+ if (telnet) {
+ /* Telnet mode */
- /* Let the client know what we're using */
- for (option = 0; option < 256; option++) {
- if (telnet_options[option]) {
- send_command(telnet_options[option], option);
- fflush(stdout);
- }
+ /* Intro is implied by telnet mode, so override whatever was asked for. */
+ show_intro = 1;
+
+ /* Set the default options */
+ set_options();
+
+ /* Let the client know what we're using */
+ for (option = 0; option < 256; option++) {
+ if (telnet_options[option]) {
+ send_command(telnet_options[option], option);
+ fflush(stdout);
}
- for (option = 0; option < 256; option++) {
- if (telnet_willack[option]) {
- send_command(telnet_willack[option], option);
- fflush(stdout);
- }
+ }
+ for (option = 0; option < 256; option++) {
+ if (telnet_willack[option]) {
+ send_command(telnet_willack[option], option);
+ fflush(stdout);
}
+ }
- /* Set the alarm handler to execute the longjmp */
- signal(SIGALRM, SIGALRM_handler);
-
- /* Negotiate options */
- if (!setjmp(environment)) {
- /* We will stop handling options after one second */
- alarm(1);
-
- /* Let's do this */
- while (!feof(stdin) && done < 2) {
- /* Get either IAC (start command) or a regular character (break, unless in SB mode) */
- unsigned char i = getchar();
- unsigned char opt = 0;
- if (i == IAC) {
- /* If IAC, get the command */
- i = getchar();
- switch (i) {
- case SE:
- /* End of extended option mode */
- sb_mode = 0;
- if (sb[0] == TTYPE) {
- /* This was a response to the TTYPE command, meaning
- * that this should be a terminal type */
- alarm(0);
- strcpy(term, &sb[2]);
- done++;
- }
- else if (sb[0] == NAWS) {
- /* This was a response to the NAWS command, meaning
- * that this should be a window size */
- alarm(0);
- terminal_width = sb[2];
- done++;
- }
- break;
- case NOP:
- /* No Op */
- send_command(NOP, 0);
- fflush(stdout);
- break;
- case WILL:
- case WONT:
- /* Will / Won't Negotiation */
- opt = getchar();
- if (!telnet_willack[opt]) {
- /* We default to WONT */
- telnet_willack[opt] = WONT;
- }
- send_command(telnet_willack[opt], opt);
- fflush(stdout);
- if ((i == WILL) && (opt == TTYPE)) {
- /* WILL TTYPE? Great, let's do that now! */
- printf("%c%c%c%c%c%c", IAC, SB, TTYPE, SEND, IAC, SE);
- fflush(stdout);
- }
- break;
- case DO:
- case DONT:
- /* Do / Don't Negotation */
- opt = getchar();
- if (!telnet_options[opt]) {
- /* We default to DONT */
- telnet_options[opt] = DONT;
- }
- send_command(telnet_options[opt], opt);
- if (opt == ECHO) {
- /* We don't really need this, as we don't accept input, but,
- * in case we do in the future, set our echo mode */
- do_echo = (i == DO);
- }
+ /* Set the alarm handler to execute the longjmp */
+ signal(SIGALRM, SIGALRM_handler);
+
+ /* Negotiate options */
+ if (!setjmp(environment)) {
+ /* We will stop handling options after one second */
+ alarm(1);
+
+ /* Let's do this */
+ while (!feof(stdin) && done < 2) {
+ /* Get either IAC (start command) or a regular character (break, unless in SB mode) */
+ unsigned char i = getchar();
+ unsigned char opt = 0;
+ if (i == IAC) {
+ /* If IAC, get the command */
+ i = getchar();
+ switch (i) {
+ case SE:
+ /* End of extended option mode */
+ sb_mode = 0;
+ if (sb[0] == TTYPE) {
+ /* This was a response to the TTYPE command, meaning
+ * that this should be a terminal type */
+ alarm(0);
+ strcpy(term, &sb[2]);
+ done++;
+ }
+ else if (sb[0] == NAWS) {
+ /* This was a response to the NAWS command, meaning
+ * that this should be a window size */
+ alarm(0);
+ terminal_width = sb[2];
+ done++;
+ }
+ break;
+ case NOP:
+ /* No Op */
+ send_command(NOP, 0);
+ fflush(stdout);
+ break;
+ case WILL:
+ case WONT:
+ /* Will / Won't Negotiation */
+ opt = getchar();
+ if (!telnet_willack[opt]) {
+ /* We default to WONT */
+ telnet_willack[opt] = WONT;
+ }
+ send_command(telnet_willack[opt], opt);
+ fflush(stdout);
+ if ((i == WILL) && (opt == TTYPE)) {
+ /* WILL TTYPE? Great, let's do that now! */
+ printf("%c%c%c%c%c%c", IAC, SB, TTYPE, SEND, IAC, SE);
fflush(stdout);
- break;
- case SB:
- /* Begin Extended Option Mode */
- sb_mode = 1;
- sb_len = 0;
- memset(sb, 0, 1024);
- break;
- case IAC:
- /* IAC IAC? That's probably not right. */
- done = 2;
- break;
- default:
- break;
- }
- } else if (sb_mode) {
- /* Extended Option Mode -> Accept character */
- if (sb_len < 1023) {
- /* Append this character to the SB string,
- * but only if it doesn't put us over
- * our limit; honestly, we shouldn't hit
- * the limit, as we're only collecting characters
- * for a terminal type or window size, but better safe than
- * sorry (and vulernable).
- */
- sb[sb_len] = i;
- sb_len++;
- }
+ }
+ break;
+ case DO:
+ case DONT:
+ /* Do / Don't Negotation */
+ opt = getchar();
+ if (!telnet_options[opt]) {
+ /* We default to DONT */
+ telnet_options[opt] = DONT;
+ }
+ send_command(telnet_options[opt], opt);
+ if (opt == ECHO) {
+ /* We don't really need this, as we don't accept input, but,
+ * in case we do in the future, set our echo mode */
+ do_echo = (i == DO);
+ }
+ fflush(stdout);
+ break;
+ case SB:
+ /* Begin Extended Option Mode */
+ sb_mode = 1;
+ sb_len = 0;
+ memset(sb, 0, 1024);
+ break;
+ case IAC:
+ /* IAC IAC? That's probably not right. */
+ done = 2;
+ break;
+ default:
+ break;
+ }
+ } else if (sb_mode) {
+ /* Extended Option Mode -> Accept character */
+ if (sb_len < 1023) {
+ /* Append this character to the SB string,
+ * but only if it doesn't put us over
+ * our limit; honestly, we shouldn't hit
+ * the limit, as we're only collecting characters
+ * for a terminal type or window size, but better safe than
+ * sorry (and vulernable).
+ */
+ sb[sb_len] = i;
+ sb_len++;
}
}
}
@@ -379,7 +425,7 @@ int main(int argc, char ** argv) {
char * nterm = getenv("TERM");
if (nterm)
strcpy(term, nterm);
-
+
/* Also get the number of columns */
struct winsize w;
ioctl(0, TIOCGWINSZ, &w);
@@ -390,7 +436,7 @@ int main(int argc, char ** argv) {
for (k = 0; k < strlen(term); ++k) {
term[k] = tolower(term[k]);
}
-
+
/* We don't want terminals wider than 80 columns */
if(terminal_width > 80) terminal_width = 80;
@@ -548,39 +594,41 @@ int main(int argc, char ** argv) {
/* Clear the screen */
printf("\033[H\033[2J\033[?25l");
- /* Display the MOTD */
- int countdown_clock = 5;
- for (k = 0; k < countdown_clock; ++k) {
- newline(3);
- printf(" \033[1mNyancat Telnet Server\033[0m");
- newline(2);
- printf(" written and run by \033[1;32mKevin Lange\033[1;34m @kevinlange\033[0m");
- newline(2);
- printf(" If things don't look right, try:");
- newline(1);
- printf(" TERM=fallback telnet ...");
- newline(2);
- printf(" Or on Windows:");
- newline(1);
- printf(" telnet -t vtnt ...");
- newline(2);
- printf(" Problems? I am also a webserver:");
- newline(1);
- printf(" \033[1;34mhttp://miku.acm.uiuc.edu\033[0m");
- newline(2);
- printf(" This is a telnet server, remember your escape keys!");
- newline(1);
- printf(" \033[1;31m^]quit\033[0m to exit");
- newline(2);
- printf(" Starting in %d... \n", countdown_clock-k);
-
- fflush(stdout);
- usleep(400000);
- printf("\033[H"); /* Reset cursor */
- }
+ if (show_intro) {
+ /* Display the MOTD */
+ int countdown_clock = 5;
+ for (k = 0; k < countdown_clock; ++k) {
+ newline(3);
+ printf(" \033[1mNyancat Telnet Server\033[0m");
+ newline(2);
+ printf(" written and run by \033[1;32mKevin Lange\033[1;34m @kevinlange\033[0m");
+ newline(2);
+ printf(" If things don't look right, try:");
+ newline(1);
+ printf(" TERM=fallback telnet ...");
+ newline(2);
+ printf(" Or on Windows:");
+ newline(1);
+ printf(" telnet -t vtnt ...");
+ newline(2);
+ printf(" Problems? I am also a webserver:");
+ newline(1);
+ printf(" \033[1;34mhttp://miku.acm.uiuc.edu\033[0m");
+ newline(2);
+ printf(" This is a telnet server, remember your escape keys!");
+ newline(1);
+ printf(" \033[1;31m^]quit\033[0m to exit");
+ newline(2);
+ printf(" Starting in %d... \n", countdown_clock-k);
- /* Clear the screen again */
- printf("\033[H\033[2J\033[?25l");
+ fflush(stdout);
+ usleep(400000);
+ printf("\033[H"); /* Reset cursor */
+ }
+
+ /* Clear the screen again */
+ printf("\033[H\033[2J\033[?25l");
+ }
/* Store the start time */
time_t start, current;
generated by cgit v1.2.3 (git 2.39.1) at 2025-10-31 11:51:01 +0000