2 #define I3__FILE__ "sighandler.c"
4 * vim:ts=4:sw=4:expandtab
6 * i3 - an improved dynamic tiling window manager
7 * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
8 * © 2009-2010 Jan-Erik Rediger
10 * sighandler.c: Interactive crash dialog upon SIGSEGV/SIGABRT/SIGFPE (offers
11 * to restart inplace).
21 #include <xcb/xcb_event.h>
23 #include <X11/keysym.h>
25 static void open_popups(void);
27 static xcb_gcontext_t pixmap_gc;
28 static xcb_pixmap_t pixmap;
29 static int raised_signal;
31 static char *crash_text[] = {
33 "To debug this problem, either attach gdb now",
35 "- 'b' to save a backtrace (needs GDB),",
36 "- 'r' to restart i3 in-place or",
37 "- 'f' to forget the current layout and restart"};
38 static int crash_text_longest = 5;
39 static int backtrace_string_index = 3;
40 static int backtrace_done = 0;
43 * Attach gdb to pid_parent and dump a backtrace to i3-backtrace.$pid in the
46 static int backtrace(void) {
47 char *tmpdir = getenv("TMPDIR");
51 pid_t pid_parent = getpid();
53 char *filename = NULL;
56 /* Find a unique filename for the backtrace (since the PID of i3 stays the
57 * same), so that we don’t overwrite earlier backtraces. */
60 sasprintf(&filename, "%s/i3-backtrace.%d.%d.txt", tmpdir, pid_parent, suffix);
62 } while (stat(filename, &bt) == 0);
64 pid_t pid_gdb = fork();
66 DLOG("Failed to fork for GDB\n");
68 } else if (pid_gdb == 0) {
76 /* close standard streams in case i3 is started from a terminal; gdb
77 * needs to run without controlling terminal for it to work properly in
83 /* We provide pipe file descriptors for stdin/stdout because gdb < 7.5
84 * crashes otherwise, see
85 * http://sourceware.org/bugzilla/show_bug.cgi?id=14114 */
86 dup2(stdin_pipe[0], STDIN_FILENO);
87 dup2(stdout_pipe[1], STDOUT_FILENO);
89 char *pid_s, *gdb_log_cmd;
90 sasprintf(&pid_s, "%d", pid_parent);
91 sasprintf(&gdb_log_cmd, "set logging file %s", filename);
101 "-ex", "set logging on",
105 execvp(args[0], args);
106 DLOG("Failed to exec GDB\n");
111 waitpid(pid_gdb, &status, 0);
113 /* see if the backtrace was succesful or not */
114 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
115 DLOG("GDB did not run properly\n");
117 } else if (stat(filename, &bt) == -1) {
118 DLOG("GDB executed successfully, but no backtrace was generated\n");
125 * Draw the window containing the info text
128 static int sig_draw_window(xcb_window_t win, int width, int height, int font_height, i3String **crash_text_i3strings) {
129 /* re-draw the background */
130 xcb_rectangle_t border = {0, 0, width, height},
131 inner = {2, 2, width - 4, height - 4};
132 xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){get_colorpixel("#FF0000")});
133 xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
134 xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){get_colorpixel("#000000")});
135 xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
137 /* restore font color */
138 set_font_colors(pixmap_gc, get_colorpixel("#FFFFFF"), get_colorpixel("#000000"));
140 char *bt_colour = "#FFFFFF";
141 if (backtrace_done < 0)
142 bt_colour = "#AA0000";
143 else if (backtrace_done > 0)
144 bt_colour = "#00AA00";
146 for (int i = 0; crash_text_i3strings[i] != NULL; ++i) {
147 /* fix the colour for the backtrace line when it finished */
148 if (i == backtrace_string_index)
149 set_font_colors(pixmap_gc, get_colorpixel(bt_colour), get_colorpixel("#000000"));
151 draw_text(crash_text_i3strings[i], pixmap, pixmap_gc,
152 8, 5 + i * font_height, width - 16);
154 /* and reset the colour again for other lines */
155 if (i == backtrace_string_index)
156 set_font_colors(pixmap_gc, get_colorpixel("#FFFFFF"), get_colorpixel("#000000"));
159 /* Copy the contents of the pixmap to the real window */
160 xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
167 * Handles keypresses of 'b', 'r' and 'f' to get a backtrace or restart i3
170 static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
171 uint16_t state = event->state;
173 /* Apparantly, after activating numlock once, the numlock modifier
174 * stays turned on (use xev(1) to verify). So, to resolve useful
175 * keysyms, we remove the numlock flag from the event state */
176 state &= ~xcb_numlock_mask;
178 xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
181 DLOG("User issued core-dump command.\n");
183 /* fork and exec/attach GDB to the parent to get a backtrace in the
185 backtrace_done = backtrace();
187 /* re-open the windows to indicate that it's finished */
201 * Opens the window we use for input/output and maps it
204 static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
205 xcb_window_t win = xcb_generate_id(conn);
210 mask |= XCB_CW_BACK_PIXEL;
213 mask |= XCB_CW_OVERRIDE_REDIRECT;
216 /* center each popup on the specified screen */
217 uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
218 y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
220 xcb_create_window(conn,
221 XCB_COPY_FROM_PARENT,
222 win, /* the window id */
223 root, /* parent == root */
224 x, y, width, height, /* dimensions */
225 0, /* border = 0, we draw our own */
226 XCB_WINDOW_CLASS_INPUT_OUTPUT,
227 XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
231 /* Map the window (= make it visible) */
232 xcb_map_window(conn, win);
237 static void open_popups() {
238 /* width and height of the popup window, so that the text fits in */
239 int crash_text_num = sizeof(crash_text) / sizeof(char *);
240 int height = 13 + (crash_text_num * config.font.height);
242 int crash_text_length = sizeof(crash_text) / sizeof(char *);
243 i3String **crash_text_i3strings = smalloc(sizeof(i3String *) * (crash_text_length + 1));
244 /* Pre-compute i3Strings for our text */
245 for (int i = 0; i < crash_text_length; ++i) {
246 crash_text_i3strings[i] = i3string_from_utf8(crash_text[i]);
248 crash_text_i3strings[crash_text_length] = NULL;
249 /* calculate width for longest text */
250 int font_width = predict_text_width(crash_text_i3strings[crash_text_longest]);
251 int width = font_width + 20;
253 /* Open a popup window on each virtual screen */
256 TAILQ_FOREACH(screen, &outputs, outputs) {
259 win = open_input_window(conn, screen->rect, width, height);
262 pixmap = xcb_generate_id(conn);
263 pixmap_gc = xcb_generate_id(conn);
264 xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
265 xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
267 /* Grab the keyboard to get all input */
268 xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
270 /* Grab the cursor inside the popup */
271 xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
272 XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
274 sig_draw_window(win, width, height, config.font.height, crash_text_i3strings);
281 * It creates a window asking the user to restart in-place
282 * or exit to generate a core dump
285 void handle_signal(int sig, siginfo_t *info, void *data) {
286 DLOG("i3 crashed. SIG: %d\n", sig);
288 struct sigaction action;
289 action.sa_handler = SIG_DFL;
290 sigaction(sig, &action, NULL);
295 xcb_generic_event_t *event;
296 /* Yay, more own eventhandlers… */
297 while ((event = xcb_wait_for_event(conn))) {
298 /* Strip off the highest bit (set if the event is generated) */
299 int type = (event->response_type & 0x7F);
300 if (type == XCB_KEY_PRESS) {
301 sig_handle_key_press(NULL, conn, (xcb_key_press_event_t *)event);
308 * Setup signal handlers to safely handle SIGSEGV and SIGFPE
311 void setup_signal_handler(void) {
312 struct sigaction action;
314 action.sa_sigaction = handle_signal;
315 action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
316 sigemptyset(&action.sa_mask);
318 /* Catch all signals with default action "Core", see signal(7) */
319 if (sigaction(SIGQUIT, &action, NULL) == -1 ||
320 sigaction(SIGILL, &action, NULL) == -1 ||
321 sigaction(SIGABRT, &action, NULL) == -1 ||
322 sigaction(SIGFPE, &action, NULL) == -1 ||
323 sigaction(SIGSEGV, &action, NULL) == -1)
324 ELOG("Could not setup signal handler");