Rework the signal handler

Rework the signal handler to be somewhat more unsafe, but conceptually
cleaner, in operation.  It now ends the use of Curses, then reraises the
signal.  Remove almost all references to abort_game.

src/exch.c

@@ -211,9 +211,6 @@ void exchange_stock (void)
 		    break;
 
 		default:
-		    if (abort_game)
-			return;
-
 		    beep();
 		}
 	    }
@@ -259,9 +256,6 @@ void visit_bank (void)
     char *buf;
 
 
-    if (abort_game)
-	return;
-
     buf = malloc(BUFSIZE);
     if (buf == NULL) {
 	err_exit_nomem();
@@ -334,9 +328,6 @@ void visit_bank (void)
 	    break;
 
 	default:
-	    if (abort_game)
-		return;
-
 	    beep();
 	}
     }
@@ -491,9 +482,6 @@ 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);
 
@@ -593,9 +581,6 @@ void trade_shares (int num, bool *bid_used)
 	    break;
 
 	default:
-	    if (abort_game)
-		return;
-
 	    beep();
 	}
     }

src/game.c

@@ -126,9 +126,6 @@ void init_game (void)
 	while (number_players == 0) {
 	    int choice = ask_number_players();
 
-	    if (abort_game)
-		return;
-
 	    if (choice == ERR) {
 		abort_game = true;
 		return;
@@ -136,9 +133,6 @@ void init_game (void)
 	    } else if (choice == 0) {
 		choice = ask_game_number();
 
-		if (abort_game)
-		    return;
-
 		if (choice != ERR) {
 		    game_num = choice;
 
@@ -168,9 +162,6 @@ void init_game (void)
 
 	    ask_player_names();
 
-	    if (abort_game)
-		return;
-
 	    deltxwin();			// "Number of players" window
 	    txrefresh();
 
@@ -230,6 +221,7 @@ void init_game (void)
     }
 
     quit_selected = false;
+    abort_game = false;
 }
 
 
@@ -285,9 +277,6 @@ static int ask_number_players (void)
 		break;
 
 	    default:
-		if (abort_game)
-		    return ERR;
-
 		beep();
 	    }
 	}
@@ -344,9 +333,6 @@ int ask_game_number (void)
 		break;
 
 	    default:
-		if (abort_game)
-		    return ERR;
-
 		beep();
 	    }
 	}
@@ -362,9 +348,6 @@ int ask_game_number (void)
 
 void ask_player_names (void)
 {
-    if (abort_game)
-	return;
-
     if (number_players == 1) {
 	// Ask for the player's name
 
@@ -379,9 +362,6 @@ 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 {
@@ -391,7 +371,7 @@ 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) == true) {
+	if (answer_yesno(curwin, attr_keycode)) {
 	    show_help();
 	}
 
@@ -452,9 +432,6 @@ void ask_player_names (void)
 		break;
 
 	    case ERR:
-		if (abort_game)
-		    return;
-
 		beep();
 		break;
 
@@ -491,7 +468,7 @@ 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) == true) {
+	if (answer_yesno(curwin, attr_keycode)) {
 	    show_help();
 	}
     }
@@ -510,8 +487,10 @@ 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) {
@@ -531,9 +510,6 @@ void end_game (void)
 	show_status(i);
     }
 
-    if (abort_game)
-	return;
-
     if (number_players == 1) {
 	l_strfmon(buf, BUFSIZE, "%1n", total_value(0));
 
@@ -595,9 +571,6 @@ 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
@@ -697,9 +670,6 @@ 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

@@ -84,13 +84,12 @@ 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

@@ -33,7 +33,6 @@
 
 
 #include <stdbool.h>
-#include <signal.h>
 
 
 /************************************************************************
@@ -196,12 +195,11 @@ 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

@@ -162,9 +162,6 @@ 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++)
 	;
@@ -359,9 +356,6 @@ void show_help (void)
 	    break;
 
 	default:
-	    if (abort_game)
-		return;
-
 	    curpage++;
 	    done = (curpage == numpages);
 	}

src/intf.c

@@ -112,8 +112,9 @@ static void init_title (void);
   Parameters: sig             - Signal number
   Returns:    (nothing)
 
-  This function handles termination signals (like SIGINT and SIGTERM) by
+  This function handles termination signals (like SIGINT, SIGTERM and
-  setting the global variable abort_game to true.
+  SIGQUIT) by clearing the screen, uninstalling itself and reraising the
+  signal.
 */
 static void sigterm_handler (int sig);
 
@@ -163,6 +164,9 @@ void init_screen (void)
     if (sigaction(SIGTERM, &sa, NULL) == -1) {
 	errno_exit("sigaction(SIGTERM)");
     }
+    if (sigaction(SIGQUIT, &sa, NULL) == -1) {
+	errno_exit("sigaction(SIGQUIT)");
+    }
 
     // Initialise the screen
     initscr();
@@ -312,13 +316,26 @@ void init_title (void)
 
 void sigterm_handler (int sig)
 {
-    /* Note that sigterm_handler() simply sets a volatile variable
+    struct sigaction sa;
-       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;
+
+    /* The following Curses functions are NOT async-signal-safe (ie, are
+       not reentrant) as they may well call malloc() or free().  However,
+       it does allow us to terminate with the correct signal without
+       having convoluted code in the main program. */
+
+    curs_set(CURS_ON);
+    clear();
+    refresh();
+    endwin();
+
+    // Reraise the same signal, using the system-default handler
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+    sa.sa_handler = SIG_DFL;
+
+    sigaction(sig, &sa, NULL);
+    raise(sig);
 }
 
 
@@ -705,10 +722,8 @@ int gettxline (WINDOW *win, char *buf, int bufsize, bool *restrict modified,
 
 	key = wgetch(win);
 	if (key == ERR) {
-	    if (abort_game) {
+	    // Do nothing on ERR
-		ret = ERR;
+	    ;
-		done = true;
-	    }
 	} else if ((key == KEY_DEFAULTVAL1 || key == KEY_DEFAULTVAL2)
 		   && defaultval != NULL && len == 0) {
 	    // Initialise buffer with the default value
@@ -1512,7 +1527,7 @@ int gettxlong (WINDOW *win, long int *restrict result, long int min,
 /***********************************************************************/
 // answer_yesno: Wait for a Yes/No answer
 
-int answer_yesno (WINDOW *win, chtype attr_keys)
+bool answer_yesno (WINDOW *win, chtype attr_keys)
 {
     int key;
     bool done;
@@ -1539,8 +1554,6 @@ int 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

@@ -534,17 +534,16 @@ 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:    int          - 1 if Yes was selected, 0 if No, ERR if error
+  Returns:    bool         - True if Yes was selected, false if No
 
   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.  If
+  "N" (for No) on the keyboard, then prints the answer using A_BOLD.
-  "Y" was selected, 1 is returned, if "N", 0 is returned.  ERR is
+  True is returned if "Y" was selected, false if "N".  Note that the
-  returned if abort_game becomes true.  Note that the cursor becomes
+  cursor becomes invisible after calling this function.
-  invisible after calling this function.
 */
-extern int answer_yesno (WINDOW *win, chtype attr_keys);
+extern bool answer_yesno (WINDOW *win, chtype attr_keys);
 
 
 /*

src/move.c

@@ -159,9 +159,6 @@ 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++) {
@@ -321,9 +318,6 @@ selection_t get_move (void)
 		    break;
 
 		default:
-		    if (abort_game)
-			return SEL_QUIT;
-
 		    beep();
 		}
 	    }
@@ -341,13 +335,10 @@ 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) != true) {
+	if (! answer_yesno(curwin, attr_keycode)) {
 	    selection = SEL_NONE;
 	}
 
-	if (abort_game)
-	    return SEL_QUIT;
-
 	// Save the game if required
 	if (selection == SEL_SAVE) {
 	    bool saved = false;
@@ -406,9 +397,6 @@ selection_t get_move (void)
 			    break;
 
 			default:
-			    if (abort_game)
-				return SEL_QUIT;
-
 			    beep();
 			}
 		    }
@@ -456,13 +444,12 @@ 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();
@@ -508,9 +495,6 @@ 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;
@@ -518,9 +502,6 @@ 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;
@@ -528,9 +509,6 @@ 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;
@@ -538,9 +516,6 @@ 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;
@@ -548,9 +523,6 @@ 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;
@@ -559,9 +531,6 @@ 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 :
@@ -627,9 +596,6 @@ 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) {
@@ -670,9 +636,6 @@ 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! */
 
@@ -827,9 +790,6 @@ 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();
@@ -992,9 +952,6 @@ void adjust_values (void)
     int which;
 
 
-    if (abort_game)
-	return;
-
     // Declare a company bankrupt!
     if (randf() > (1.0 - COMPANY_BANKRUPTCY)) {
 	which = randi(MAX_COMPANIES);
@@ -1128,9 +1085,6 @@ 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/trader.c

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