i3
src/sighandler.c
Go to the documentation of this file.
00001 /*
00002  * vim:ts=4:sw=4:expandtab
00003  *
00004  * i3 - an improved dynamic tiling window manager
00005  * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
00006  * © 2009-2010 Jan-Erik Rediger
00007  *
00008  * sighandler.c: Interactive crash dialog upon SIGSEGV/SIGABRT/SIGFPE (offers
00009  *               to restart inplace).
00010  *
00011  */
00012 #include "all.h"
00013 
00014 #include <ev.h>
00015 #include <iconv.h>
00016 #include <signal.h>
00017 
00018 #include <xcb/xcb_event.h>
00019 
00020 #include <X11/keysym.h>
00021 
00022 static xcb_gcontext_t pixmap_gc;
00023 static xcb_pixmap_t pixmap;
00024 static int raised_signal;
00025 
00026 static char *crash_text[] = {
00027     "i3 just crashed.",
00028     "To debug this problem, either attach gdb now",
00029     "or press",
00030     "- 'e' to exit and get a core-dump,",
00031     "- 'r' to restart i3 in-place or",
00032     "- 'f' to forget the current layout and restart"
00033 };
00034 static int crash_text_longest = 5;
00035 
00036 /*
00037  * Draw the window containing the info text
00038  *
00039  */
00040 static int sig_draw_window(xcb_window_t win, int width, int height, int font_height) {
00041     /* re-draw the background */
00042     xcb_rectangle_t border = { 0, 0, width, height},
00043                     inner = { 2, 2, width - 4, height - 4};
00044     xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#FF0000") });
00045     xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
00046     xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#000000") });
00047     xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
00048 
00049     /* restore font color */
00050     xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#FFFFFF") });
00051 
00052     for (int i = 0; i < sizeof(crash_text) / sizeof(char*); i++) {
00053         int text_len = strlen(crash_text[i]);
00054         char *full_text = convert_utf8_to_ucs2(crash_text[i], &text_len);
00055         xcb_image_text_16(conn, text_len, pixmap, pixmap_gc, 8 /* X */,
00056                           3 + (i + 1) * font_height /* Y = baseline of font */,
00057                           (xcb_char2b_t*)full_text);
00058         free(full_text);
00059     }
00060 
00061     /* Copy the contents of the pixmap to the real window */
00062     xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
00063     xcb_flush(conn);
00064 
00065     return 1;
00066 }
00067 
00068 /*
00069  * Handles keypresses of 'e' or 'r' to exit or restart i3
00070  *
00071  */
00072 static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
00073     uint16_t state = event->state;
00074 
00075     /* Apparantly, after activating numlock once, the numlock modifier
00076      * stays turned on (use xev(1) to verify). So, to resolve useful
00077      * keysyms, we remove the numlock flag from the event state */
00078     state &= ~xcb_numlock_mask;
00079 
00080     xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
00081 
00082     if (sym == 'e') {
00083         DLOG("User issued exit-command, raising error again.\n");
00084         raise(raised_signal);
00085         exit(1);
00086     }
00087 
00088     if (sym == 'r')
00089         i3_restart(false);
00090 
00091     if (sym == 'f')
00092         i3_restart(true);
00093 
00094     return 1;
00095 }
00096 
00097 /*
00098  * Opens the window we use for input/output and maps it
00099  *
00100  */
00101 static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
00102     xcb_window_t win = xcb_generate_id(conn);
00103 
00104     uint32_t mask = 0;
00105     uint32_t values[2];
00106 
00107     mask |= XCB_CW_BACK_PIXEL;
00108     values[0] = 0;
00109 
00110     mask |= XCB_CW_OVERRIDE_REDIRECT;
00111     values[1] = 1;
00112 
00113     /* center each popup on the specified screen */
00114     uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
00115              y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
00116 
00117     xcb_create_window(conn,
00118                       XCB_COPY_FROM_PARENT,
00119                       win, /* the window id */
00120                       root, /* parent == root */
00121                       x, y, width, height, /* dimensions */
00122                       0, /* border = 0, we draw our own */
00123                       XCB_WINDOW_CLASS_INPUT_OUTPUT,
00124                       XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
00125                       mask,
00126                       values);
00127 
00128     /* Map the window (= make it visible) */
00129     xcb_map_window(conn, win);
00130 
00131     return win;
00132 }
00133 
00134 /*
00135  * Handle signals
00136  * It creates a window asking the user to restart in-place
00137  * or exit to generate a core dump
00138  *
00139  */
00140 void handle_signal(int sig, siginfo_t *info, void *data) {
00141     DLOG("i3 crashed. SIG: %d\n", sig);
00142 
00143     struct sigaction action;
00144     action.sa_handler = SIG_DFL;
00145     sigaction(sig, &action, NULL);
00146     raised_signal = sig;
00147 
00148     /* width and height of the popup window, so that the text fits in */
00149     int crash_text_num = sizeof(crash_text) / sizeof(char*);
00150     int height = 13 + (crash_text_num * config.font.height);
00151 
00152     /* calculate width for longest text */
00153     int text_len = strlen(crash_text[crash_text_longest]);
00154     char *longest_text = convert_utf8_to_ucs2(crash_text[crash_text_longest], &text_len);
00155     int font_width = predict_text_width(longest_text, text_len);
00156     int width = font_width + 20;
00157 
00158     /* Open a popup window on each virtual screen */
00159     Output *screen;
00160     xcb_window_t win;
00161     TAILQ_FOREACH(screen, &outputs, outputs) {
00162         if (!screen->active)
00163             continue;
00164         win = open_input_window(conn, screen->rect, width, height);
00165 
00166         /* Create pixmap */
00167         pixmap = xcb_generate_id(conn);
00168         pixmap_gc = xcb_generate_id(conn);
00169         xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
00170         xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
00171 
00172         /* Create graphics context */
00173         xcb_change_gc(conn, pixmap_gc, XCB_GC_FONT, (uint32_t[]){ config.font.id });
00174 
00175         /* Grab the keyboard to get all input */
00176         xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
00177 
00178         /* Grab the cursor inside the popup */
00179         xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
00180                          XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
00181 
00182         sig_draw_window(win, width, height, config.font.height);
00183         xcb_flush(conn);
00184     }
00185 
00186     xcb_generic_event_t *event;
00187     /* Yay, more own eventhandlers… */
00188     while ((event = xcb_wait_for_event(conn))) {
00189         /* Strip off the highest bit (set if the event is generated) */
00190         int type = (event->response_type & 0x7F);
00191         if (type == XCB_KEY_PRESS) {
00192             sig_handle_key_press(NULL, conn, (xcb_key_press_event_t*)event);
00193         }
00194         free(event);
00195     }
00196 }
00197 
00198 /*
00199  * Setup signal handlers to safely handle SIGSEGV and SIGFPE
00200  *
00201  */
00202 void setup_signal_handler() {
00203     struct sigaction action;
00204 
00205     action.sa_sigaction = handle_signal;
00206     action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
00207     sigemptyset(&action.sa_mask);
00208 
00209     if (sigaction(SIGSEGV, &action, NULL) == -1 ||
00210         sigaction(SIGABRT, &action, NULL) == -1 ||
00211         sigaction(SIGFPE, &action, NULL) == -1)
00212         ELOG("Could not setup signal handler");
00213 }