i3
sighandler.c
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1 /*
2  * vim:ts=4:sw=4:expandtab
3  *
4  * i3 - an improved dynamic tiling window manager
5  * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
6  * © 2009-2010 Jan-Erik Rediger
7  *
8  * sighandler.c: Interactive crash dialog upon SIGSEGV/SIGABRT/SIGFPE (offers
9  * to restart inplace).
10  *
11  */
12 #include "all.h"
13 
14 #include <ev.h>
15 #include <iconv.h>
16 #include <signal.h>
17 
18 #include <xcb/xcb_event.h>
19 
20 #include <X11/keysym.h>
21 
22 static xcb_gcontext_t pixmap_gc;
23 static xcb_pixmap_t pixmap;
24 static int raised_signal;
25 
26 static char *crash_text[] = {
27  "i3 just crashed.",
28  "To debug this problem, either attach gdb now",
29  "or press",
30  "- 'e' to exit and get a core-dump,",
31  "- 'r' to restart i3 in-place or",
32  "- 'f' to forget the current layout and restart"
33 };
34 static int crash_text_longest = 5;
35 
36 /*
37  * Draw the window containing the info text
38  *
39  */
40 static int sig_draw_window(xcb_window_t win, int width, int height, int font_height) {
41  /* re-draw the background */
42  xcb_rectangle_t border = { 0, 0, width, height},
43  inner = { 2, 2, width - 4, height - 4};
44  xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#FF0000") });
45  xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
46  xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#000000") });
47  xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
48 
49  /* restore font color */
50  set_font_colors(pixmap_gc, get_colorpixel("#FFFFFF"), get_colorpixel("#000000"));
51 
52  for (int i = 0; i < sizeof(crash_text) / sizeof(char*); i++) {
53  draw_text(crash_text[i], strlen(crash_text[i]), false, pixmap, pixmap_gc,
54  8, 5 + i * font_height, width - 16);
55  }
56 
57  /* Copy the contents of the pixmap to the real window */
58  xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
59  xcb_flush(conn);
60 
61  return 1;
62 }
63 
64 /*
65  * Handles keypresses of 'e' or 'r' to exit or restart i3
66  *
67  */
68 static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
69  uint16_t state = event->state;
70 
71  /* Apparantly, after activating numlock once, the numlock modifier
72  * stays turned on (use xev(1) to verify). So, to resolve useful
73  * keysyms, we remove the numlock flag from the event state */
74  state &= ~xcb_numlock_mask;
75 
76  xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
77 
78  if (sym == 'e') {
79  DLOG("User issued exit-command, raising error again.\n");
80  raise(raised_signal);
81  exit(1);
82  }
83 
84  if (sym == 'r')
85  i3_restart(false);
86 
87  if (sym == 'f')
88  i3_restart(true);
89 
90  return 1;
91 }
92 
93 /*
94  * Opens the window we use for input/output and maps it
95  *
96  */
97 static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
98  xcb_window_t win = xcb_generate_id(conn);
99 
100  uint32_t mask = 0;
101  uint32_t values[2];
102 
103  mask |= XCB_CW_BACK_PIXEL;
104  values[0] = 0;
105 
106  mask |= XCB_CW_OVERRIDE_REDIRECT;
107  values[1] = 1;
108 
109  /* center each popup on the specified screen */
110  uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
111  y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
112 
113  xcb_create_window(conn,
114  XCB_COPY_FROM_PARENT,
115  win, /* the window id */
116  root, /* parent == root */
117  x, y, width, height, /* dimensions */
118  0, /* border = 0, we draw our own */
119  XCB_WINDOW_CLASS_INPUT_OUTPUT,
120  XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
121  mask,
122  values);
123 
124  /* Map the window (= make it visible) */
125  xcb_map_window(conn, win);
126 
127  return win;
128 }
129 
130 /*
131  * Handle signals
132  * It creates a window asking the user to restart in-place
133  * or exit to generate a core dump
134  *
135  */
136 void handle_signal(int sig, siginfo_t *info, void *data) {
137  DLOG("i3 crashed. SIG: %d\n", sig);
138 
139  struct sigaction action;
140  action.sa_handler = SIG_DFL;
141  sigaction(sig, &action, NULL);
142  raised_signal = sig;
143 
144  /* width and height of the popup window, so that the text fits in */
145  int crash_text_num = sizeof(crash_text) / sizeof(char*);
146  int height = 13 + (crash_text_num * config.font.height);
147 
148  /* calculate width for longest text */
149  size_t text_len = strlen(crash_text[crash_text_longest]);
150  xcb_char2b_t *longest_text = convert_utf8_to_ucs2(crash_text[crash_text_longest], &text_len);
151  int font_width = predict_text_width((char *)longest_text, text_len, true);
152  int width = font_width + 20;
153 
154  /* Open a popup window on each virtual screen */
155  Output *screen;
156  xcb_window_t win;
157  TAILQ_FOREACH(screen, &outputs, outputs) {
158  if (!screen->active)
159  continue;
160  win = open_input_window(conn, screen->rect, width, height);
161 
162  /* Create pixmap */
163  pixmap = xcb_generate_id(conn);
164  pixmap_gc = xcb_generate_id(conn);
165  xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
166  xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
167 
168  /* Grab the keyboard to get all input */
169  xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
170 
171  /* Grab the cursor inside the popup */
172  xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
173  XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
174 
175  sig_draw_window(win, width, height, config.font.height);
176  xcb_flush(conn);
177  }
178 
179  xcb_generic_event_t *event;
180  /* Yay, more own eventhandlers… */
181  while ((event = xcb_wait_for_event(conn))) {
182  /* Strip off the highest bit (set if the event is generated) */
183  int type = (event->response_type & 0x7F);
184  if (type == XCB_KEY_PRESS) {
185  sig_handle_key_press(NULL, conn, (xcb_key_press_event_t*)event);
186  }
187  free(event);
188  }
189 }
190 
191 /*
192  * Setup signal handlers to safely handle SIGSEGV and SIGFPE
193  *
194  */
196  struct sigaction action;
197 
198  action.sa_sigaction = handle_signal;
199  action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
200  sigemptyset(&action.sa_mask);
201 
202  /* Catch all signals with default action "Core", see signal(7) */
203  if (sigaction(SIGQUIT, &action, NULL) == -1 ||
204  sigaction(SIGILL, &action, NULL) == -1 ||
205  sigaction(SIGABRT, &action, NULL) == -1 ||
206  sigaction(SIGFPE, &action, NULL) == -1 ||
207  sigaction(SIGSEGV, &action, NULL) == -1)
208  ELOG("Could not setup signal handler");
209 }