Add a signal handler for SIGINT and SIGTERM

Add a signal handler for SIGINT and SIGTERM, as well as sprinklings of
checks to abort_game.  Although Ncurses DOES define handlers for SIGINT
and SIGTERM, they do not always seem to work correctly under many
operating systems.

.gitignore

@@ -21,11 +21,11 @@ Makefile.in
 /build-aux/install-sh
 /build-aux/missing
 
+/build-aux/snippet/_Noreturn.h
 /build-aux/snippet/arg-nonnull.h
 /build-aux/snippet/c++defs.h
 /build-aux/snippet/unused-parameter.h
 /build-aux/snippet/warn-on-use.h
-/build-aux/snippet/_Noreturn.h
 
 /po/POTFILES
 /po/remove-potcdate.sed

lib/.gitignore

@@ -1,17 +1,17 @@
 Makefile.am
 alloca.in.h
 asnprintf.c
-ctype.in.h
 c-ctype.c
 c-ctype.h
 c-strcase.h
 c-strcasecmp.c
 c-strncasecmp.c
+ctype.in.h
 dosname.h
 errno.in.h
+float+.h
 float.c
 float.in.h
-float+.h
 fprintf.c
 fpucw.h
 frexp.c
@@ -34,19 +34,18 @@ iconv_open-osf.gperf
 iconv_open-solaris.gperf
 iconv_open.c
 isnan.c
-isnand.c
 isnand-nolibm.h
-isnanf.c
+isnand.c
 isnanf-nolibm.h
-isnanl.c
+isnanf.c
 isnanl-nolibm.h
+isnanl.c
 langinfo.in.h
 locale.in.h
 malloc.c
 math.in.h
 memchr.c
 memchr.valgrind
-printf.c
 printf-args.c
 printf-args.h
 printf-frexp.c
@@ -55,9 +54,14 @@ printf-frexpl.c
 printf-frexpl.h
 printf-parse.c
 printf-parse.h
+printf.c
+sig-handler.h
+sigaction.c
+signal.in.h
 signbitd.c
 signbitf.c
 signbitl.c
+sigprocmask.c
 size_max.h
 snprintf.c
 stat.c
@@ -65,16 +69,16 @@ stdarg.in.h
 stdbool.in.h
 stddef.in.h
 stdint.in.h
-stdio.in.h
 stdio-impl.h
+stdio.in.h
 stdlib.in.h
+str-two-way.h
 strdup.c
 striconv.c
 striconv.h
 string.in.h
 strncat.c
 strstr.c
-str-two-way.h
 sys_stat.in.h
 sys_time.in.h
 time.in.h
@@ -103,6 +107,7 @@ iconv_open-solaris.h
 langinfo.h
 locale.h
 math.h
+signal.h
 stdio.h
 stdlib.h
 string.h

m4/.gitignore

@@ -19,8 +19,8 @@ frexpl.m4
 getopt.m4
 gettext.m4
 gettimeofday.m4
-glibc21.m4
 glibc2.m4
+glibc21.m4
 gnulib-common.m4
 gnulib-comp.m4
 gnulib-tool.m4
@@ -30,8 +30,8 @@ iconv_open.m4
 include_next.m4
 inline.m4
 intdiv0.m4
-intldir.m4
 intl.m4
+intldir.m4
 intlmacosx.m4
 intmax.m4
 intmax_t.m4
@@ -59,16 +59,19 @@ multiarch.m4
 nls.m4
 nocrash.m4
 po.m4
-printf.m4
 printf-frexp.m4
 printf-frexpl.m4
-printf-posix.m4
 printf-posix-rpl.m4
+printf-posix.m4
+printf.m4
 progtest.m4
+sigaction.m4
+signal_h.m4
+signalblocking.m4
 signbit.m4
 size_max.m4
-snprintf.m4
 snprintf-posix.m4
+snprintf.m4
 stat.m4
 stdarg.m4
 stdbool.m4
@@ -90,8 +93,8 @@ unistd_h.m4
 vasnprintf.m4
 vfprintf-posix.m4
 visibility.m4
-vsnprintf.m4
 vsnprintf-posix.m4
+vsnprintf.m4
 warn-on-use.m4
 wchar_h.m4
 wchar_t.m4

m4/gnulib-cache.m4

@@ -15,7 +15,7 @@
 
 
 # Specification in the form of a command-line invocation:
-#   gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --no-conditional-dependencies --no-libtool --macro-prefix=gl assert config-h ctype fprintf-posix getopt-gnu gettext gettext-h gettimeofday langinfo locale printf-posix snprintf-posix stat stdarg stdbool stdio strdup-posix striconv string strncat strstr sys_stat sys_time unistd vfprintf-posix vsnprintf-posix
+#   gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --no-conditional-dependencies --no-libtool --macro-prefix=gl assert config-h ctype fprintf-posix getopt-gnu gettext gettext-h gettimeofday langinfo locale printf-posix sigaction signal snprintf-posix stat stdarg stdbool stdio strdup-posix striconv string strncat strstr sys_stat sys_time unistd vfprintf-posix vsnprintf-posix
 
 # Specification in the form of a few gnulib-tool.m4 macro invocations:
 gl_LOCAL_DIR([])
@@ -31,6 +31,8 @@ gl_MODULES([
   langinfo
   locale
   printf-posix
+  sigaction
+  signal
   snprintf-posix
   stat
   stdarg

src/exch.c

@@ -211,6 +211,9 @@ void exchange_stock (void)
 		    break;
 
 		default:
+		    if (abort_game)
+			return;
+
 		    beep();
 		}
 	    }
@@ -256,6 +259,9 @@ void visit_bank (void)
     char *buf;
 
 
+    if (abort_game)
+	return;
+
     buf = malloc(BUFSIZE);
     if (buf == NULL) {
 	err_exit_nomem();
@@ -328,6 +334,9 @@ void visit_bank (void)
 	    break;
 
 	default:
+	    if (abort_game)
+		return;
+
 	    beep();
 	}
     }
@@ -482,6 +491,9 @@ void trade_shares (int num, bool *bid_used)
     char *buf;
 
 
+    if (abort_game)
+	return;
+
     assert(num >= 0 && num < MAX_COMPANIES);
     assert(company[num].on_map);
 
@@ -581,6 +593,9 @@ void trade_shares (int num, bool *bid_used)
 	    break;
 
 	default:
+	    if (abort_game)
+		return;
+
 	    beep();
 	}
     }

src/game.c

@@ -126,6 +126,9 @@ void init_game (void)
 	while (number_players == 0) {
 	    int choice = ask_number_players();
 
+	    if (abort_game)
+		return;
+
 	    if (choice == ERR) {
 		abort_game = true;
 		return;
@@ -133,6 +136,9 @@ void init_game (void)
 	    } else if (choice == 0) {
 		choice = ask_game_number();
 
+		if (abort_game)
+		    return;
+
 		if (choice != ERR) {
 		    game_num = choice;
 
@@ -162,6 +168,9 @@ void init_game (void)
 
 	    ask_player_names();
 
+	    if (abort_game)
+		return;
+
 	    deltxwin();			// "Number of players" window
 	    txrefresh();
 
@@ -221,7 +230,6 @@ void init_game (void)
     }
 
     quit_selected = false;
-    abort_game = false;
 }
 
 
@@ -277,6 +285,9 @@ static int ask_number_players (void)
 		break;
 
 	    default:
+		if (abort_game)
+		    return ERR;
+
 		beep();
 	    }
 	}
@@ -333,6 +344,9 @@ int ask_game_number (void)
 		break;
 
 	    default:
+		if (abort_game)
+		    return ERR;
+
 		beep();
 	    }
 	}
@@ -348,6 +362,9 @@ int ask_game_number (void)
 
 void ask_player_names (void)
 {
+    if (abort_game)
+	return;
+
     if (number_players == 1) {
 	// Ask for the player's name
 
@@ -362,6 +379,9 @@ void ask_player_names (void)
 	while (true) {
 	    int ret = gettxstr(curwin, &player[0].name, NULL, false,
 			       2, x, w, attr_input_field);
+	    if (abort_game)
+		return;
+
 	    if (ret == OK && strlen(player[0].name) != 0) {
 		break;
 	    } else {
@@ -371,7 +391,7 @@ void ask_player_names (void)
 
 	newtxwin(5, 44, 6, WCENTER, true, attr_normal_window);
 	mvwaddstr(curwin, 2, 2, "Do you need any instructions?");
-	if (answer_yesno(curwin, attr_keycode)) {
+	if (answer_yesno(curwin, attr_keycode) == true) {
 	    show_help();
 	}
 
@@ -432,6 +452,9 @@ void ask_player_names (void)
 		break;
 
 	    case ERR:
+		if (abort_game)
+		    return;
+
 		beep();
 		break;
 
@@ -468,7 +491,7 @@ void ask_player_names (void)
 
 	newtxwin(5, 50, 6, WCENTER, true, attr_normal_window);
 	mvwaddstr(curwin, 2, 2, "Does any player need instructions?");
-	if (answer_yesno(curwin, attr_keycode)) {
+	if (answer_yesno(curwin, attr_keycode) == true) {
 	    show_help();
 	}
     }
@@ -487,10 +510,8 @@ void end_game (void)
     char *buf;
 
 
-    if (abort_game) {
+    if (abort_game)
-	// init_game() was cancelled by user
 	return;
-    }
 
     buf = malloc(BUFSIZE);
     if (buf == NULL) {
@@ -510,6 +531,9 @@ void end_game (void)
 	show_status(i);
     }
 
+    if (abort_game)
+	return;
+
     if (number_players == 1) {
 	l_strfmon(buf, BUFSIZE, "%1n", total_value(0));
 
@@ -571,6 +595,9 @@ void show_map (bool closewin)
     int n, x, y;
 
 
+    if (abort_game)
+	return;
+
     newtxwin(MAX_Y + 4, WIN_COLS, 1, WCENTER, true, attr_map_window);
 
     // Draw various borders
@@ -670,6 +697,9 @@ void show_status (int num)
     int i, line;
 
 
+    if (abort_game)
+	return;
+
     assert(num >= 0 && num < number_players);
 
     newtxwin(MAX_COMPANIES + 15, WIN_COLS, 1, WCENTER, true,

src/globals.c

@@ -84,12 +84,13 @@ bool	game_loaded	= false;	// True if game was loaded from disk
 int	game_num	= 0;		// Game number (1-9)
 
 bool	quit_selected	= false;	// Is a player trying to quit the game?
-bool	abort_game	= false;	// Abort game without declaring winner?
 
 bool	option_no_color     = false;	// True if --no-color was specified
 bool	option_dont_encrypt = false;	// True if --dont-encrypt was specified
 int	option_max_turn     = 0;	// Max. turns if --max-turn was specified
 
+volatile sig_atomic_t abort_game = false; // Abort game as quickly as possible?
+
 
 /***********************************************************************/
 // End of file

src/globals.h

@@ -33,6 +33,7 @@
 
 
 #include <stdbool.h>
+#include <signal.h>
 
 
 /************************************************************************
@@ -195,11 +196,12 @@ extern bool	game_loaded;		// True if game was loaded from disk
 extern int	game_num;		// Game number (1-9)
 
 extern bool	quit_selected;		// Is a player trying to quit the game?
-extern bool	abort_game;		// Abort game without declaring winner?
 
 extern bool	option_no_color;	// True if --no-color was specified
 extern bool	option_dont_encrypt;	// True if --dont-encrypt was specified
 extern int	option_max_turn;	// Max. turns if --max-turn was specified
 
+extern volatile sig_atomic_t abort_game; // Abort game as quickly as possible?
+
 
 #endif /* included_GLOBALS_H */

src/help.c

@@ -162,6 +162,9 @@ void show_help (void)
     bool done = false;
 
 
+    if (abort_game)
+	return;
+
     // Count how many pages appear in the help text
     for (numpages = 0; help_text[numpages] != NULL; numpages++)
 	;
@@ -356,6 +359,9 @@ void show_help (void)
 	    break;
 
 	default:
+	    if (abort_game)
+		return;
+
 	    curpage++;
 	    done = (curpage == numpages);
 	}

src/intf.c

@@ -101,6 +101,7 @@ txwin_t *firstwin = NULL;	// First (bottom-most) txwin structure
   Parameters: dest          - Destination buffer of size BUFSIZE
               src           - Source buffer of size BUFSIZE
               isfloat       - True if src contains a floating point number
+  Returns:    (nothing)
 
   This helper function copies the string in src to dest, performing
   certain fixups along the way.  In particular, thousands separators are
@@ -114,6 +115,17 @@ static void txinput_fixup (char *restrict dest, char *restrict src,
 			   bool isfloat);
 
 
+/*
+  Function:   sigterm_handler - Handle program termination signals
+  Parameters: sig             - Signal number
+  Returns:    (nothing)
+
+  This function handles termination signals (like SIGINT and SIGTERM) by
+  setting the global variable abort_game to true.
+*/
+static void sigterm_handler (int sig);
+
+
 /************************************************************************
 *             Basic text input/output function definitions              *
 ************************************************************************/
@@ -126,6 +138,22 @@ static void txinput_fixup (char *restrict dest, char *restrict src,
 
 void init_screen (void)
 {
+    struct sigaction sa;
+
+
+    // Initialise signal handlers
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+    sa.sa_handler = sigterm_handler;
+
+    if (sigaction(SIGINT, &sa, NULL) == -1) {
+	errno_exit("sigaction(SIGINT)");
+    }
+    if (sigaction(SIGTERM, &sa, NULL) == -1) {
+	errno_exit("sigaction(SIGTERM)");
+    }
+
+    // Initialise the screen
     initscr();
 
     if (COLS < MIN_COLS || LINES < MIN_LINES) {
@@ -259,6 +287,21 @@ void end_screen (void)
 }
 
 
+/***********************************************************************/
+// sigterm_handler: Handle program termination signals
+
+void sigterm_handler (int sig)
+{
+    /* Note that sigterm_handler() simply sets a volatile variable
+       instead of directly terminating, as functions like endwin() and
+       end_screen() are NOT reentrant.  A side-effect of doing this,
+       however, is that the main program needs to have abort_game checks
+       scattered all over it. */
+
+    abort_game = true;
+}
+
+
 /***********************************************************************/
 // newtxwin: Create a new window, inserted into window stack
 
@@ -642,8 +685,10 @@ int gettxline (WINDOW *win, char *buf, int bufsize, bool *restrict modified,
 
 	key = wgetch(win);
 	if (key == ERR) {
-	    // Do nothing on ERR
+	    if (abort_game) {
-	    ;
+		ret = ERR;
+		done = true;
+	    }
 	} else if ((key == KEY_DEFAULTVAL1 || key == KEY_DEFAULTVAL2)
 		   && defaultval != NULL && len == 0) {
 	    // Initialise buffer with the default value
@@ -1447,7 +1492,7 @@ int gettxlong (WINDOW *win, long int *restrict result, long int min,
 /***********************************************************************/
 // answer_yesno: Wait for a Yes/No answer
 
-bool answer_yesno (WINDOW *win, chtype attr_keys)
+int answer_yesno (WINDOW *win, chtype attr_keys)
 {
     int key;
     bool done;
@@ -1474,6 +1519,8 @@ bool answer_yesno (WINDOW *win, chtype attr_keys)
 
 	if (key == 'Y' || key == 'N') {
 	    done = true;
+	} else if (abort_game) {
+	    return ERR;
 	} else {
 	    beep();
 	}

src/intf.h

@@ -534,16 +534,17 @@ extern int gettxlong (WINDOW *win, long int *restrict result, long int min,
   Function:   answer_yesno - Wait for a Yes/No answer
   Parameters: win          - Window to use (should be curwin)
               attr_keys    - Window rendition to use for key choices
-  Returns:    bool         - True if Yes was selected, false if No
+  Returns:    int          - 1 if Yes was selected, 0 if No, ERR if error
 
   This function prompts the user by printing " [Y/N] " using appropriate
   character renditions ("Y" and "N" in attr_keys, the rest in the current
   rendition), then waits for the user to press either "Y" (for Yes) or
-  "N" (for No) on the keyboard, then prints the answer using A_BOLD.
+  "N" (for No) on the keyboard, then prints the answer using A_BOLD.  If
-  True is returned if "Y" was selected, false if "N".  Note that the
+  "Y" was selected, 1 is returned, if "N", 0 is returned.  ERR is
-  cursor becomes invisible after calling this function.
+  returned if abort_game becomes true.  Note that the cursor becomes
+  invisible after calling this function.
 */
-extern bool answer_yesno (WINDOW *win, chtype attr_keys);
+extern int answer_yesno (WINDOW *win, chtype attr_keys);
 
 
 /*

src/move.c

@@ -159,6 +159,9 @@ void select_moves (void)
     bool unique;
 
 
+    if (abort_game)
+	return;
+
     // How many empty spaces are there in the galaxy map?
     count = 0;
     for (x = 0; x < MAX_X; x++) {
@@ -318,6 +321,9 @@ selection_t get_move (void)
 		    break;
 
 		default:
+		    if (abort_game)
+			return SEL_QUIT;
+
 		    beep();
 		}
 	    }
@@ -335,10 +341,13 @@ selection_t get_move (void)
 
 	// Ask the player to confirm their choice
 	mvwaddstr(curwin, 2, 22, "Are you sure?");
-	if (! answer_yesno(curwin, attr_keycode)) {
+	if (answer_yesno(curwin, attr_keycode) != true) {
 	    selection = SEL_NONE;
 	}
 
+	if (abort_game)
+	    return SEL_QUIT;
+
 	// Save the game if required
 	if (selection == SEL_SAVE) {
 	    bool saved = false;
@@ -397,6 +406,9 @@ selection_t get_move (void)
 			    break;
 
 			default:
+			    if (abort_game)
+				return SEL_QUIT;
+
 			    beep();
 			}
 		    }
@@ -444,12 +456,13 @@ selection_t get_move (void)
 
 void process_move (selection_t selection)
 {
+    if (abort_game)
+	return;
+
     if (selection == SEL_QUIT) {
 	// The players want to end the game
 	quit_selected = true;
-    }
 
-    if (quit_selected || abort_game) {
 	deltxwin();			// "Select move" window
 	deltxwin();			// Galaxy map window
 	txrefresh();
@@ -495,6 +508,9 @@ void process_move (selection_t selection)
 		assign_vals(x, y, left, right, up, down);
 	    }
 
+	    if (abort_game)
+		return;
+
 	    if (IS_MAP_COMPANY(left) && IS_MAP_COMPANY(up)
 		&& left != up) {
 		galaxy_map[x][y] = left;
@@ -502,6 +518,9 @@ void process_move (selection_t selection)
 		assign_vals(x, y, left, right, up, down);
 	    }
 
+	    if (abort_game)
+		return;
+
 	    if (IS_MAP_COMPANY(left) && IS_MAP_COMPANY(down)
 		&& left != down) {
 		galaxy_map[x][y] = left;
@@ -509,6 +528,9 @@ void process_move (selection_t selection)
 		assign_vals(x, y, left, right, up, down);
 	    }
 
+	    if (abort_game)
+		return;
+
 	    if (IS_MAP_COMPANY(right) && IS_MAP_COMPANY(up)
 		&& right != up) {
 		galaxy_map[x][y] = right;
@@ -516,6 +538,9 @@ void process_move (selection_t selection)
 		assign_vals(x, y, left, right, up, down);
 	    }
 
+	    if (abort_game)
+		return;
+
 	    if (IS_MAP_COMPANY(right) && IS_MAP_COMPANY(down)
 		&& right != down) {
 		galaxy_map[x][y] = right;
@@ -523,6 +548,9 @@ void process_move (selection_t selection)
 		assign_vals(x, y, left, right, up, down);
 	    }
 
+	    if (abort_game)
+		return;
+
 	    if (IS_MAP_COMPANY(up) && IS_MAP_COMPANY(down)
 		&& up != down) {
 		galaxy_map[x][y] = up;
@@ -531,6 +559,9 @@ void process_move (selection_t selection)
 	    }
 	}
 
+	if (abort_game)
+	    return;
+
 	// See if an existing company can be expanded
 	nearby = (IS_MAP_COMPANY(left)    ? left :
 		  (IS_MAP_COMPANY(right)  ? right :
@@ -596,6 +627,9 @@ void next_player (void)
     bool all_out;
 
 
+    if (abort_game)
+	return;
+
     all_out = true;
     for (i = 0; i < number_players; i++) {
 	if (player[i].in_game) {
@@ -636,6 +670,9 @@ void bankrupt_player (bool forced)
     int i;
 
 
+    if (abort_game)
+	return;
+
     /* It would be nice if we had functions that would do word-wrapping
        for us automatically! */
 
@@ -790,6 +827,9 @@ void merge_companies (map_val_t a, map_val_t b)
     char *buf;
 
 
+    if (abort_game)
+	return;
+
     buf = malloc(BUFSIZE);
     if (buf == NULL) {
 	err_exit_nomem();
@@ -952,6 +992,9 @@ void adjust_values (void)
     int which;
 
 
+    if (abort_game)
+	return;
+
     // Declare a company bankrupt!
     if (randf() > (1.0 - COMPANY_BANKRUPTCY)) {
 	which = randi(MAX_COMPANIES);
@@ -1085,6 +1128,9 @@ void adjust_values (void)
 	interest_rate /= randf() + INTEREST_RATE_DIVIDER;
     }
 
+    if (abort_game)
+	return;
+
     // Calculate current player's debt
     player[current_player].debt *= interest_rate + 1.0;
 

src/system.h

@@ -64,6 +64,7 @@
 // Headers defined by X/Open Single Unix Specification v4
 
 #include <unistd.h>
+#include <signal.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <monetary.h>

src/trader.c

@@ -180,7 +180,7 @@ int main (int argc, char *argv[])
 
     // Finish up...
     end_program();
-    return EXIT_SUCCESS;
+    return abort_game ? EXIT_FAILURE : EXIT_SUCCESS;
 }