added popup for handling SIGSEGV or SIGFPE

the popup is placed on each of the virtual screens
the user can decide to restart or quit i3
in case of an exit a core-dump is generated

include/sighandler.h

@@ -0,0 +1,21 @@
+/*
+ * vim:ts=8:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ *
+ * © 2009 Michael Stapelberg and contributors
+ * © 2009 Jan-Erik Rediger
+ *
+ * See file LICENSE for license information.
+ *
+ */
+#ifndef _SIGHANDLER_H
+#define _SIGHANDLER_H
+
+/*
+ * Setup signal handlers to safely handle SIGSEGV and SIGFPE
+ *
+ */
+void setup_signal_handler();
+
+#endif

include/util.h

@@ -150,6 +150,13 @@ void switch_layout_mode(xcb_connection_t *conn, Container *container, int mode);
 Client *get_matching_client(xcb_connection_t *conn,
                             const char *window_classtitle, Client *specific);
 
+/*
+ * Restart i3 in-place
+ * appends -a to argument list to disable autostart
+ *
+ */
+void i3_restart();
+
 #if defined(__OpenBSD__)
 /* OpenBSD does not provide memmem(), so we provide FreeBSD’s implementation */
 void *memmem(const void *l, size_t l_len, const void *s, size_t s_len);

src/commands.c

@@ -31,6 +31,7 @@
 #include "commands.h"
 #include "resize.h"
 #include "log.h"
+#include "sighandler.h"
 
 bool focus_window_in_container(xcb_connection_t *conn, Container *container, direction_t direction) {
         /* If this container is empty, we’re done */
@@ -759,29 +760,6 @@ static void travel_focus_stack(xcb_connection_t *conn, const char *arguments) {
                 }
 }
 
-/*
- * Goes through the list of arguments (for exec()) and checks if the given argument
- * is present. If not, it copies the arguments (because we cannot realloc it) and
- * appends the given argument.
- *
- */
-static char **append_argument(char **original, char *argument) {
-        int num_args;
-        for (num_args = 0; original[num_args] != NULL; num_args++) {
-                DLOG("original argument: \"%s\"\n", original[num_args]);
-                /* If the argument is already present we return the original pointer */
-                if (strcmp(original[num_args], argument) == 0)
-                        return original;
-        }
-        /* Copy the original array */
-        char **result = smalloc((num_args+2) * sizeof(char*));
-        memcpy(result, original, num_args * sizeof(char*));
-        result[num_args] = argument;
-        result[num_args+1] = NULL;
-
-        return result;
-}
-
 /* 
  * Switch to next or previous existing workspace
  *
@@ -965,12 +943,7 @@ void parse_command(xcb_connection_t *conn, const char *command) {
 
         /* Is it <restart>? Then restart in place. */
         if (STARTS_WITH(command, "restart")) {
-                LOG("restarting \"%s\"...\n", start_argv[0]);
-                /* make sure -a is in the argument list or append it */
-                start_argv = append_argument(start_argv, "-a");
-
-                execvp(start_argv[0], start_argv);
-                /* not reached */
+                i3_restart();
         }
 
         if (STARTS_WITH(command, "kill")) {

src/mainx.c

@@ -49,6 +49,7 @@
 #include "manage.h"
 #include "ipc.h"
 #include "log.h"
+#include "sighandler.h"
 
 xcb_connection_t *global_conn;
 
@@ -499,6 +500,7 @@ int main(int argc, char *argv[], char *env[]) {
         /* Handle the events which arrived until now */
         xcb_check_cb(NULL, NULL, 0);
 
+        setup_signal_handler();
         /* Ungrab the server to receive events and enter libev’s eventloop */
         xcb_ungrab_server(conn);
         ev_loop(loop, 0);

src/sighandler.c

@@ -0,0 +1,215 @@
+/*
+ * vim:ts=8:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ *
+ * © 2009 Michael Stapelberg and contributors
+ * © 2009 Jan-Erik Rediger
+ *
+ * See file LICENSE for license information.
+ *
+ * sighandler.c: contains all functions for signal handling
+ *
+ */
+#include <ev.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <iconv.h>
+#include <signal.h>
+
+#include <xcb/xcb.h>
+#include <xcb/xcb_aux.h>
+#include <xcb/xcb_event.h>
+#include <xcb/xcb_keysyms.h>
+
+#include <X11/keysym.h>
+
+#include "i3.h"
+#include "util.h"
+#include "xcb.h"
+#include "log.h"
+#include "config.h"
+#include "xinerama.h"
+
+static xcb_gcontext_t pixmap_gc;
+static xcb_pixmap_t pixmap;
+static int raised_signal;
+
+static char *crash_text[] = {
+        "i3 just crashed.",
+        "To debug this problem, either attach gdb now",
+        "or press 'e' to exit and get a core-dump.",
+        "If you want to keep your session,",
+        "press 'r' to restart i3 in-place."
+};
+static int crash_text_longest = 1;
+
+/*
+ * Draw the window containing the info text
+ *
+ */
+static int sig_draw_window(xcb_connection_t *conn, xcb_window_t win, int width, int height, int font_height) {
+        /* re-draw the background */
+        xcb_rectangle_t border = {0, 0, width, height}, inner = {2, 2, width-4, height-4};
+        xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#FF0000"));
+        xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
+        xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#000000"));
+        xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
+
+        /* restore font color */
+        xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#FFFFFF"));
+
+        char *full_text;
+        int text_len;
+        int i;
+        int crash_text_num = sizeof(crash_text) / sizeof(char*);
+        for (i = 0; i < crash_text_num; i++) {
+                text_len = strlen(crash_text[i]);
+                full_text = convert_utf8_to_ucs2(crash_text[i], &text_len);
+                xcb_image_text_16(conn, text_len, pixmap, pixmap_gc, 8 /* X */,
+                                3 + (i+1)*font_height /* Y = baseline of font */, (xcb_char2b_t*)full_text);
+                free(full_text);
+        }
+
+        /* Copy the contents of the pixmap to the real window */
+        xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
+        xcb_flush(conn);
+
+        return 1;
+}
+
+
+/*
+ * Handles keypresses of 'e' or 'r' to exit or restart i3
+ *
+ */
+static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
+        xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, event->state);
+
+        if (sym == 'e') {
+                LOG("User issued exit-command, raising error again.\n");
+                raise(raised_signal);
+                exit(1);
+        }
+        if (sym == 'r')
+                i3_restart();
+
+        return 1;
+}
+
+/*
+ * Opens the window we use for input/output and maps it
+ *
+ */
+static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
+        xcb_window_t root = xcb_setup_roots_iterator(xcb_get_setup(conn)).data->root;
+        xcb_window_t win = xcb_generate_id(conn);
+
+        uint32_t mask = 0;
+        uint32_t values[3];
+
+        mask |= XCB_CW_BACK_PIXEL;
+        values[0] = 0;
+
+        mask |= XCB_CW_OVERRIDE_REDIRECT;
+        values[1] = 1;
+
+        mask |= XCB_CW_EVENT_MASK;
+        values[2] = XCB_EVENT_MASK_EXPOSURE;
+
+        /* center each popup on the specified screen */
+        uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width/2)),
+                 y = screen_rect.y + ((screen_rect.height / 2) - (height/2));
+
+        xcb_create_window(conn,
+                        XCB_COPY_FROM_PARENT,
+                        win, /* the window id */
+                        root, /* parent == root */
+                        x, y, width, height, /* dimensions */
+                        0, /* border = 0, we draw our own */
+                        XCB_WINDOW_CLASS_INPUT_OUTPUT,
+                        XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
+                        mask,
+                        values);
+
+        /* Map the window (= make it visible) */
+        xcb_map_window(conn, win);
+
+        return win;
+}
+
+/*
+ * Handle signals
+ * It creates a window asking the user to restart in-place
+ * or exit to generate a core dump
+ *
+ */
+void handle_signal(int sig, siginfo_t *info, void *data) {
+        LOG("i3 crashed. SIG: %d\n", sig);
+
+        struct sigaction action;
+        action.sa_handler = SIG_DFL;
+        sigaction(sig, &action, NULL);
+        raised_signal = sig;
+
+        xcb_connection_t *conn = global_conn;
+
+        /* Set up event handlers for key press and key release */
+        xcb_event_handlers_t sig_evenths;
+        memset(&sig_evenths, 0, sizeof(xcb_event_handlers_t));
+        xcb_event_handlers_init(conn, &sig_evenths);
+        xcb_event_set_key_press_handler(&sig_evenths, sig_handle_key_press, NULL);
+
+        i3Font *font = load_font(conn, config.font);
+
+        /* width and height of the popup window, so that the text fits in */
+        int crash_text_num = sizeof(crash_text) / sizeof(char*);
+        int height = 13 + (crash_text_num * font->height);
+
+        /* calculate width for longest text */
+        int text_len = strlen(crash_text[crash_text_longest]);
+        char *longest_text = convert_utf8_to_ucs2(crash_text[crash_text_longest], &text_len);
+        int font_width = predict_text_width(conn, config.font, longest_text, text_len);
+        int width = font_width + 20;
+
+        /* Open an popup window on each virtual screen */
+        i3Screen *screen;
+        xcb_window_t win;
+        TAILQ_FOREACH(screen, virtual_screens, screens) {
+                LOG("%d, %d, %d, %d\n", screen->rect.width, screen->rect.height, screen->rect.x, screen->rect.y);
+
+                win = open_input_window(conn, screen->rect, width, height);
+
+                /* Create pixmap */
+                pixmap = xcb_generate_id(conn);
+                pixmap_gc = xcb_generate_id(conn);
+                xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
+                xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
+
+                /* Create graphics context */
+                xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FONT, font->id);
+
+                /* Grab the keyboard to get all input */
+                xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
+
+                sig_draw_window(conn, win, width, height, font->height);
+                xcb_flush(conn);
+        }
+
+        xcb_event_wait_for_event_loop(&sig_evenths);
+}
+
+/*
+ * Setup signal handlers to safely handle SIGSEGV and SIGFPE
+ *
+ */
+void setup_signal_handler() {
+        struct sigaction action;
+        action.sa_sigaction = handle_signal;
+        action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
+        sigemptyset(&action.sa_mask);
+        sigaction(SIGSEGV, &action, NULL);
+        sigaction(SIGFPE, &action, NULL);
+}

src/util.c

@@ -463,6 +463,43 @@ done:
         return matching;
 }
 
+/*
+ * Goes through the list of arguments (for exec()) and checks if the given argument
+ * is present. If not, it copies the arguments (because we cannot realloc it) and
+ * appends the given argument.
+ *
+ */
+static char **append_argument(char **original, char *argument) {
+        int num_args;
+        for (num_args = 0; original[num_args] != NULL; num_args++) {
+                DLOG("original argument: \"%s\"\n", original[num_args]);
+                /* If the argument is already present we return the original pointer */
+                if (strcmp(original[num_args], argument) == 0)
+                        return original;
+        }
+        /* Copy the original array */
+        char **result = smalloc((num_args+2) * sizeof(char*));
+        memcpy(result, original, num_args * sizeof(char*));
+        result[num_args] = argument;
+        result[num_args+1] = NULL;
+
+        return result;
+}
+
+/*
+ * Restart i3 in-place
+ * appends -a to argument list to disable autostart
+ *
+ */
+void i3_restart() {
+        LOG("restarting \"%s\"...\n", start_argv[0]);
+        /* make sure -a is in the argument list or append it */
+        start_argv = append_argument(start_argv, "-a");
+
+        execvp(start_argv[0], start_argv);
+        /* not reached */
+}
+
 #if defined(__OpenBSD__)
 
 /*