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src/sighandler.c

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00001 /*
00002  * vim:ts=8:expandtab
00003  *
00004  * i3 - an improved dynamic tiling window manager
00005  *
00006  * © 2009-2010 Michael Stapelberg and contributors
00007  * © 2009-2010 Jan-Erik Rediger
00008  *
00009  * See file LICENSE for license information.
00010  *
00011  * sighandler.c: contains all functions for signal handling
00012  *
00013  */
00014 #include <ev.h>
00015 #include <stdio.h>
00016 #include <stdlib.h>
00017 #include <string.h>
00018 #include <unistd.h>
00019 #include <iconv.h>
00020 #include <signal.h>
00021 
00022 #include <xcb/xcb.h>
00023 #include <xcb/xcb_aux.h>
00024 #include <xcb/xcb_event.h>
00025 #include <xcb/xcb_keysyms.h>
00026 
00027 #include <X11/keysym.h>
00028 
00029 #include "i3.h"
00030 #include "util.h"
00031 #include "xcb.h"
00032 #include "log.h"
00033 #include "config.h"
00034 #include "randr.h"
00035 
00036 static xcb_gcontext_t pixmap_gc;
00037 static xcb_pixmap_t pixmap;
00038 static int raised_signal;
00039 
00040 static char *crash_text[] = {
00041         "i3 just crashed.",
00042         "To debug this problem, either attach gdb now",
00043         "or press 'e' to exit and get a core-dump.",
00044         "If you want to keep your session,",
00045         "press 'r' to restart i3 in-place."
00046 };
00047 static int crash_text_longest = 1;
00048 
00049 /*
00050  * Draw the window containing the info text
00051  *
00052  */
00053 static int sig_draw_window(xcb_connection_t *conn, xcb_window_t win, int width, int height, int font_height) {
00054         /* re-draw the background */
00055         xcb_rectangle_t border = { 0, 0, width, height},
00056                         inner = { 2, 2, width - 4, height - 4};
00057         xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#FF0000"));
00058         xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
00059         xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#000000"));
00060         xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
00061 
00062         /* restore font color */
00063         xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FOREGROUND, get_colorpixel(conn, "#FFFFFF"));
00064 
00065         for (int i = 0; i < sizeof(crash_text) / sizeof(char*); i++) {
00066                 int text_len = strlen(crash_text[i]);
00067                 char *full_text = convert_utf8_to_ucs2(crash_text[i], &text_len);
00068                 xcb_image_text_16(conn, text_len, pixmap, pixmap_gc, 8 /* X */,
00069                                 3 + (i + 1) * font_height /* Y = baseline of font */,
00070                                 (xcb_char2b_t*)full_text);
00071                 free(full_text);
00072         }
00073 
00074         /* Copy the contents of the pixmap to the real window */
00075         xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
00076         xcb_flush(conn);
00077 
00078         return 1;
00079 }
00080 
00081 /*
00082  * Handles keypresses of 'e' or 'r' to exit or restart i3
00083  *
00084  */
00085 static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
00086         uint16_t state = event->state;
00087 
00088         /* Apparantly, after activating numlock once, the numlock modifier
00089          * stays turned on (use xev(1) to verify). So, to resolve useful
00090          * keysyms, we remove the numlock flag from the event state */
00091         state &= ~xcb_numlock_mask;
00092 
00093         xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
00094 
00095         if (sym == 'e') {
00096                 DLOG("User issued exit-command, raising error again.\n");
00097                 raise(raised_signal);
00098                 exit(1);
00099         }
00100 
00101         if (sym == 'r')
00102                 i3_restart();
00103 
00104         return 1;
00105 }
00106 
00107 /*
00108  * Opens the window we use for input/output and maps it
00109  *
00110  */
00111 static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
00112         xcb_window_t root = xcb_setup_roots_iterator(xcb_get_setup(conn)).data->root;
00113         xcb_window_t win = xcb_generate_id(conn);
00114 
00115         uint32_t mask = 0;
00116         uint32_t values[2];
00117 
00118         mask |= XCB_CW_BACK_PIXEL;
00119         values[0] = 0;
00120 
00121         mask |= XCB_CW_OVERRIDE_REDIRECT;
00122         values[1] = 1;
00123 
00124         /* center each popup on the specified screen */
00125         uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
00126                  y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
00127 
00128         xcb_create_window(conn,
00129                         XCB_COPY_FROM_PARENT,
00130                         win, /* the window id */
00131                         root, /* parent == root */
00132                         x, y, width, height, /* dimensions */
00133                         0, /* border = 0, we draw our own */
00134                         XCB_WINDOW_CLASS_INPUT_OUTPUT,
00135                         XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
00136                         mask,
00137                         values);
00138 
00139         /* Map the window (= make it visible) */
00140         xcb_map_window(conn, win);
00141 
00142         return win;
00143 }
00144 
00145 /*
00146  * Handle signals
00147  * It creates a window asking the user to restart in-place
00148  * or exit to generate a core dump
00149  *
00150  */
00151 void handle_signal(int sig, siginfo_t *info, void *data) {
00152         DLOG("i3 crashed. SIG: %d\n", sig);
00153 
00154         struct sigaction action;
00155         action.sa_handler = SIG_DFL;
00156         sigaction(sig, &action, NULL);
00157         raised_signal = sig;
00158 
00159         xcb_connection_t *conn = global_conn;
00160 
00161         /* setup event handler for key presses */
00162         xcb_event_handlers_t sig_evenths;
00163         memset(&sig_evenths, 0, sizeof(xcb_event_handlers_t));
00164         xcb_event_handlers_init(conn, &sig_evenths);
00165         xcb_event_set_key_press_handler(&sig_evenths, sig_handle_key_press, NULL);
00166 
00167         i3Font *font = load_font(conn, config.font);
00168 
00169         /* width and height of the popup window, so that the text fits in */
00170         int crash_text_num = sizeof(crash_text) / sizeof(char*);
00171         int height = 13 + (crash_text_num * font->height);
00172 
00173         /* calculate width for longest text */
00174         int text_len = strlen(crash_text[crash_text_longest]);
00175         char *longest_text = convert_utf8_to_ucs2(crash_text[crash_text_longest], &text_len);
00176         int font_width = predict_text_width(conn, config.font, longest_text, text_len);
00177         int width = font_width + 20;
00178 
00179         /* Open a popup window on each virtual screen */
00180         Output *screen;
00181         xcb_window_t win;
00182         TAILQ_FOREACH(screen, &outputs, outputs) {
00183                 if (!screen->active)
00184                         continue;
00185                 win = open_input_window(conn, screen->rect, width, height);
00186 
00187                 /* Create pixmap */
00188                 pixmap = xcb_generate_id(conn);
00189                 pixmap_gc = xcb_generate_id(conn);
00190                 xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
00191                 xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
00192 
00193                 /* Create graphics context */
00194                 xcb_change_gc_single(conn, pixmap_gc, XCB_GC_FONT, font->id);
00195 
00196                 /* Grab the keyboard to get all input */
00197                 xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
00198 
00199                 /* Grab the cursor inside the popup */
00200                 xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
00201                                  XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
00202 
00203                 sig_draw_window(conn, win, width, height, font->height);
00204                 xcb_flush(conn);
00205         }
00206 
00207         xcb_event_wait_for_event_loop(&sig_evenths);
00208 }
00209 
00210 /*
00211  * Setup signal handlers to safely handle SIGSEGV and SIGFPE
00212  *
00213  */
00214 void setup_signal_handler() {
00215         struct sigaction action;
00216 
00217         action.sa_sigaction = handle_signal;
00218         action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
00219         sigemptyset(&action.sa_mask);
00220 
00221         if (sigaction(SIGSEGV, &action, NULL) == -1 ||
00222             sigaction(SIGFPE, &action, NULL) == -1)
00223                 ELOG("Could not setup signal handler");
00224 }

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