2 * vim:ts=4:sw=4:expandtab
4 * i3 - an improved dynamic tiling window manager
5 * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
6 * © 2009 Jan-Erik Rediger
8 * sighandler.c: Interactive crash dialog upon SIGSEGV/SIGABRT/SIGFPE (offers
19 #include <xcb/xcb_event.h>
21 #include <X11/keysym.h>
23 static void open_popups(void);
25 static xcb_gcontext_t pixmap_gc;
26 static xcb_pixmap_t pixmap;
27 static int raised_signal;
29 static char *crash_text[] = {
31 "To debug this problem, either attach gdb now",
33 "- 'b' to save a backtrace (needs GDB),",
34 "- 'r' to restart i3 in-place or",
35 "- 'f' to forget the current layout and restart"};
36 static int crash_text_longest = 5;
37 static int backtrace_string_index = 3;
38 static int backtrace_done = 0;
41 * Attach gdb to pid_parent and dump a backtrace to i3-backtrace.$pid in the
44 static int backtrace(void) {
45 char *tmpdir = getenv("TMPDIR");
49 pid_t pid_parent = getpid();
51 char *filename = NULL;
54 /* Find a unique filename for the backtrace (since the PID of i3 stays the
55 * same), so that we don’t overwrite earlier backtraces. */
58 sasprintf(&filename, "%s/i3-backtrace.%d.%d.txt", tmpdir, pid_parent, suffix);
60 } while (stat(filename, &bt) == 0);
62 pid_t pid_gdb = fork();
64 DLOG("Failed to fork for GDB\n");
66 } else if (pid_gdb == 0) {
71 if (pipe(stdin_pipe) == -1) {
72 ELOG("Failed to init stdin_pipe\n");
75 if (pipe(stdout_pipe) == -1) {
76 ELOG("Failed to init stdout_pipe\n");
80 /* close standard streams in case i3 is started from a terminal; gdb
81 * needs to run without controlling terminal for it to work properly in
87 /* We provide pipe file descriptors for stdin/stdout because gdb < 7.5
88 * crashes otherwise, see
89 * http://sourceware.org/bugzilla/show_bug.cgi?id=14114 */
90 dup2(stdin_pipe[0], STDIN_FILENO);
91 dup2(stdout_pipe[1], STDOUT_FILENO);
93 char *pid_s, *gdb_log_cmd;
94 sasprintf(&pid_s, "%d", pid_parent);
95 sasprintf(&gdb_log_cmd, "set logging file %s", filename);
105 "-ex", "set logging on",
109 execvp(args[0], args);
110 DLOG("Failed to exec GDB\n");
115 waitpid(pid_gdb, &status, 0);
117 /* see if the backtrace was successful or not */
118 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
119 DLOG("GDB did not run properly\n");
121 } else if (stat(filename, &bt) == -1) {
122 DLOG("GDB executed successfully, but no backtrace was generated\n");
129 * Draw the window containing the info text
132 static int sig_draw_window(xcb_window_t win, int width, int height, int font_height, i3String **crash_text_i3strings) {
133 /* re-draw the background */
134 xcb_rectangle_t border = {0, 0, width, height},
135 inner = {2, 2, width - 4, height - 4};
136 xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){get_colorpixel("#FF0000")});
137 xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
138 xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){get_colorpixel("#000000")});
139 xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
141 /* restore font color */
142 set_font_colors(pixmap_gc, draw_util_hex_to_color("#FFFFFF"), draw_util_hex_to_color("#000000"));
144 char *bt_colour = "#FFFFFF";
145 if (backtrace_done < 0)
146 bt_colour = "#AA0000";
147 else if (backtrace_done > 0)
148 bt_colour = "#00AA00";
150 for (int i = 0; crash_text_i3strings[i] != NULL; ++i) {
151 /* fix the colour for the backtrace line when it finished */
152 if (i == backtrace_string_index)
153 set_font_colors(pixmap_gc, draw_util_hex_to_color(bt_colour), draw_util_hex_to_color("#000000"));
155 draw_text(crash_text_i3strings[i], pixmap, pixmap_gc, NULL,
156 8, 5 + i * font_height, width - 16);
158 /* and reset the colour again for other lines */
159 if (i == backtrace_string_index)
160 set_font_colors(pixmap_gc, draw_util_hex_to_color("#FFFFFF"), draw_util_hex_to_color("#000000"));
163 /* Copy the contents of the pixmap to the real window */
164 xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
171 * Handles keypresses of 'b', 'r' and 'f' to get a backtrace or restart i3
174 static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
175 uint16_t state = event->state;
177 /* Apparently, after activating numlock once, the numlock modifier
178 * stays turned on (use xev(1) to verify). So, to resolve useful
179 * keysyms, we remove the numlock flag from the event state */
180 state &= ~xcb_numlock_mask;
182 xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
185 DLOG("User issued core-dump command.\n");
187 /* fork and exec/attach GDB to the parent to get a backtrace in the
189 backtrace_done = backtrace();
191 /* re-open the windows to indicate that it's finished */
205 * Opens the window we use for input/output and maps it
208 static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
209 xcb_window_t win = xcb_generate_id(conn);
214 mask |= XCB_CW_BACK_PIXEL;
217 mask |= XCB_CW_OVERRIDE_REDIRECT;
220 /* center each popup on the specified screen */
221 uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
222 y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
224 xcb_create_window(conn,
225 XCB_COPY_FROM_PARENT,
226 win, /* the window id */
227 root, /* parent == root */
228 x, y, width, height, /* dimensions */
229 0, /* border = 0, we draw our own */
230 XCB_WINDOW_CLASS_INPUT_OUTPUT,
231 XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
235 /* Map the window (= make it visible) */
236 xcb_map_window(conn, win);
241 static void open_popups() {
242 /* width and height of the popup window, so that the text fits in */
243 int crash_text_num = sizeof(crash_text) / sizeof(char *);
244 int height = 13 + (crash_text_num * config.font.height);
246 int crash_text_length = sizeof(crash_text) / sizeof(char *);
247 i3String **crash_text_i3strings = smalloc(sizeof(i3String *) * (crash_text_length + 1));
248 /* Pre-compute i3Strings for our text */
249 for (int i = 0; i < crash_text_length; ++i) {
250 crash_text_i3strings[i] = i3string_from_utf8(crash_text[i]);
252 crash_text_i3strings[crash_text_length] = NULL;
253 /* calculate width for longest text */
254 int font_width = predict_text_width(crash_text_i3strings[crash_text_longest]);
255 int width = font_width + 20;
257 /* Open a popup window on each virtual screen */
260 TAILQ_FOREACH(screen, &outputs, outputs) {
263 win = open_input_window(conn, screen->rect, width, height);
266 pixmap = xcb_generate_id(conn);
267 pixmap_gc = xcb_generate_id(conn);
268 xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
269 xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
271 /* Grab the keyboard to get all input */
272 xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
274 /* Grab the cursor inside the popup */
275 xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
276 XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
278 sig_draw_window(win, width, height, config.font.height, crash_text_i3strings);
285 * It creates a window asking the user to restart in-place
286 * or exit to generate a core dump
289 void handle_signal(int sig, siginfo_t *info, void *data) {
290 DLOG("i3 crashed. SIG: %d\n", sig);
292 struct sigaction action;
293 action.sa_handler = SIG_DFL;
294 sigaction(sig, &action, NULL);
299 xcb_generic_event_t *event;
300 /* Yay, more own eventhandlers… */
301 while ((event = xcb_wait_for_event(conn))) {
302 /* Strip off the highest bit (set if the event is generated) */
303 int type = (event->response_type & 0x7F);
304 if (type == XCB_KEY_PRESS) {
305 sig_handle_key_press(NULL, conn, (xcb_key_press_event_t *)event);
312 * Setup signal handlers to safely handle SIGSEGV and SIGFPE
315 void setup_signal_handler(void) {
316 struct sigaction action;
318 action.sa_sigaction = handle_signal;
319 action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
320 sigemptyset(&action.sa_mask);
322 /* Catch all signals with default action "Core", see signal(7) */
323 if (sigaction(SIGQUIT, &action, NULL) == -1 ||
324 sigaction(SIGILL, &action, NULL) == -1 ||
325 sigaction(SIGABRT, &action, NULL) == -1 ||
326 sigaction(SIGFPE, &action, NULL) == -1 ||
327 sigaction(SIGSEGV, &action, NULL) == -1)
328 ELOG("Could not setup signal handler.\n");