gri3-wm/src/sighandler.c

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#undef I3__FILE__
#define I3__FILE__ "sighandler.c"
/*
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* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
* © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
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* © 2009-2010 Jan-Erik Rediger
*
* sighandler.c: Interactive crash dialog upon SIGSEGV/SIGABRT/SIGFPE (offers
* to restart inplace).
*
*/
#include "all.h"
#include <ev.h>
#include <iconv.h>
#include <signal.h>
#include <sys/wait.h>
#include <xcb/xcb_event.h>
#include <X11/keysym.h>
static void open_popups(void);
static xcb_gcontext_t pixmap_gc;
static xcb_pixmap_t pixmap;
static int raised_signal;
static char *crash_text[] = {
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"i3 just crashed.",
"To debug this problem, either attach gdb now",
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"or press",
"- 'b' to save a backtrace (needs GDB),",
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"- 'r' to restart i3 in-place or",
"- 'f' to forget the current layout and restart"
};
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static int crash_text_longest = 5;
static int backtrace_string_index = 3;
static int backtrace_done = 0;
/*
* Attach gdb to pid_parent and dump a backtrace to i3-backtrace.$pid in the
* tmpdir
*/
static int backtrace(void) {
char *tmpdir = getenv("TMPDIR");
if (tmpdir == NULL)
tmpdir = "/tmp";
pid_t pid_parent = getpid();
char *filename = NULL;
int suffix = 0;
struct stat bt;
/* Find a unique filename for the backtrace (since the PID of i3 stays the
* same), so that we dont overwrite earlier backtraces. */
do {
FREE(filename);
sasprintf(&filename, "%s/i3-backtrace.%d.%d.txt", tmpdir, pid_parent, suffix);
suffix++;
} while (stat(filename, &bt) == 0);
pid_t pid_gdb = fork();
if (pid_gdb < 0) {
DLOG("Failed to fork for GDB\n");
return -1;
} else if (pid_gdb == 0) {
/* child */
int stdin_pipe[2],
stdout_pipe[2];
pipe(stdin_pipe);
pipe(stdout_pipe);
/* close standard streams in case i3 is started from a terminal; gdb
* needs to run without controlling terminal for it to work properly in
* this situation */
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
/* We provide pipe file descriptors for stdin/stdout because gdb < 7.5
* crashes otherwise, see
* http://sourceware.org/bugzilla/show_bug.cgi?id=14114 */
dup2(stdin_pipe[0], STDIN_FILENO);
dup2(stdout_pipe[1], STDOUT_FILENO);
char *pid_s, *gdb_log_cmd;
sasprintf(&pid_s, "%d", pid_parent);
sasprintf(&gdb_log_cmd, "set logging file %s", filename);
char *args[] = {
"gdb",
start_argv[0],
"-p",
pid_s,
"-batch",
"-nx",
"-ex", gdb_log_cmd,
"-ex", "set logging on",
"-ex", "bt full",
"-ex", "quit",
NULL
};
execvp(args[0], args);
DLOG("Failed to exec GDB\n");
exit(1);
}
int status = 0;
waitpid(pid_gdb, &status, 0);
/* see if the backtrace was succesful or not */
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
DLOG("GDB did not run properly\n");
return -1;
} else if (stat(filename, &bt) == -1) {
DLOG("GDB executed successfully, but no backtrace was generated\n");
return -1;
}
return 1;
}
/*
* Draw the window containing the info text
*
*/
static int sig_draw_window(xcb_window_t win, int width, int height, int font_height, i3String **crash_text_i3strings) {
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/* re-draw the background */
xcb_rectangle_t border = { 0, 0, width, height},
inner = { 2, 2, width - 4, height - 4};
xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#FF0000") });
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xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &border);
xcb_change_gc(conn, pixmap_gc, XCB_GC_FOREGROUND, (uint32_t[]){ get_colorpixel("#000000") });
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xcb_poly_fill_rectangle(conn, pixmap, pixmap_gc, 1, &inner);
/* restore font color */
set_font_colors(pixmap_gc, get_colorpixel("#FFFFFF"), get_colorpixel("#000000"));
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char *bt_colour = "#FFFFFF";
if (backtrace_done < 0)
bt_colour = "#AA0000";
else if (backtrace_done > 0)
bt_colour = "#00AA00";
for (int i = 0; crash_text_i3strings[i] != NULL; ++i) {
/* fix the colour for the backtrace line when it finished */
if (i == backtrace_string_index)
set_font_colors(pixmap_gc, get_colorpixel(bt_colour), get_colorpixel("#000000"));
draw_text(crash_text_i3strings[i], pixmap, pixmap_gc,
8, 5 + i * font_height, width - 16);
/* and reset the colour again for other lines */
if (i == backtrace_string_index)
set_font_colors(pixmap_gc, get_colorpixel("#FFFFFF"), get_colorpixel("#000000"));
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}
/* Copy the contents of the pixmap to the real window */
xcb_copy_area(conn, pixmap, win, pixmap_gc, 0, 0, 0, 0, width, height);
xcb_flush(conn);
return 1;
}
/*
* Handles keypresses of 'b', 'r' and 'f' to get a backtrace or restart i3
*
*/
static int sig_handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event) {
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uint16_t state = event->state;
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/* Apparantly, after activating numlock once, the numlock modifier
* stays turned on (use xev(1) to verify). So, to resolve useful
* keysyms, we remove the numlock flag from the event state */
state &= ~xcb_numlock_mask;
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xcb_keysym_t sym = xcb_key_press_lookup_keysym(keysyms, event, state);
if (sym == 'b') {
DLOG("User issued core-dump command.\n");
/* fork and exec/attach GDB to the parent to get a backtrace in the
* tmpdir */
backtrace_done = backtrace();
/* re-open the windows to indicate that it's finished */
open_popups();
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}
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if (sym == 'r')
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i3_restart(false);
if (sym == 'f')
i3_restart(true);
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return 1;
}
/*
* Opens the window we use for input/output and maps it
*
*/
static xcb_window_t open_input_window(xcb_connection_t *conn, Rect screen_rect, uint32_t width, uint32_t height) {
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xcb_window_t win = xcb_generate_id(conn);
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uint32_t mask = 0;
uint32_t values[2];
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mask |= XCB_CW_BACK_PIXEL;
values[0] = 0;
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mask |= XCB_CW_OVERRIDE_REDIRECT;
values[1] = 1;
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/* center each popup on the specified screen */
uint32_t x = screen_rect.x + ((screen_rect.width / 2) - (width / 2)),
y = screen_rect.y + ((screen_rect.height / 2) - (height / 2));
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xcb_create_window(conn,
XCB_COPY_FROM_PARENT,
win, /* the window id */
root, /* parent == root */
x, y, width, height, /* dimensions */
0, /* border = 0, we draw our own */
XCB_WINDOW_CLASS_INPUT_OUTPUT,
XCB_WINDOW_CLASS_COPY_FROM_PARENT, /* copy visual from parent */
mask,
values);
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/* Map the window (= make it visible) */
xcb_map_window(conn, win);
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return win;
}
static void open_popups() {
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/* width and height of the popup window, so that the text fits in */
int crash_text_num = sizeof(crash_text) / sizeof(char*);
int height = 13 + (crash_text_num * config.font.height);
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int crash_text_length = sizeof(crash_text) / sizeof(char*);
i3String **crash_text_i3strings = smalloc(sizeof(i3String *) * (crash_text_length + 1));
/* Pre-compute i3Strings for our text */
for (int i = 0; i < crash_text_length; ++i) {
crash_text_i3strings[i] = i3string_from_utf8(crash_text[i]);
}
crash_text_i3strings[crash_text_length] = NULL;
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/* calculate width for longest text */
int font_width = predict_text_width(crash_text_i3strings[crash_text_longest]);
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int width = font_width + 20;
/* Open a popup window on each virtual screen */
Output *screen;
xcb_window_t win;
TAILQ_FOREACH(screen, &outputs, outputs) {
if (!screen->active)
continue;
win = open_input_window(conn, screen->rect, width, height);
/* Create pixmap */
pixmap = xcb_generate_id(conn);
pixmap_gc = xcb_generate_id(conn);
xcb_create_pixmap(conn, root_depth, pixmap, win, width, height);
xcb_create_gc(conn, pixmap_gc, pixmap, 0, 0);
/* Grab the keyboard to get all input */
xcb_grab_keyboard(conn, false, win, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
/* Grab the cursor inside the popup */
xcb_grab_pointer(conn, false, win, XCB_NONE, XCB_GRAB_MODE_ASYNC,
XCB_GRAB_MODE_ASYNC, win, XCB_NONE, XCB_CURRENT_TIME);
sig_draw_window(win, width, height, config.font.height, crash_text_i3strings);
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xcb_flush(conn);
}
}
/*
* Handle signals
* It creates a window asking the user to restart in-place
* or exit to generate a core dump
*
*/
void handle_signal(int sig, siginfo_t *info, void *data) {
DLOG("i3 crashed. SIG: %d\n", sig);
struct sigaction action;
action.sa_handler = SIG_DFL;
sigaction(sig, &action, NULL);
raised_signal = sig;
open_popups();
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xcb_generic_event_t *event;
/* Yay, more own eventhandlers… */
while ((event = xcb_wait_for_event(conn))) {
/* Strip off the highest bit (set if the event is generated) */
int type = (event->response_type & 0x7F);
if (type == XCB_KEY_PRESS) {
sig_handle_key_press(NULL, conn, (xcb_key_press_event_t*)event);
}
free(event);
}
}
/*
* Setup signal handlers to safely handle SIGSEGV and SIGFPE
*
*/
void setup_signal_handler(void) {
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struct sigaction action;
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action.sa_sigaction = handle_signal;
action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
sigemptyset(&action.sa_mask);
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/* Catch all signals with default action "Core", see signal(7) */
if (sigaction(SIGQUIT, &action, NULL) == -1 ||
sigaction(SIGILL, &action, NULL) == -1 ||
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sigaction(SIGABRT, &action, NULL) == -1 ||
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sigaction(SIGFPE, &action, NULL) == -1 ||
sigaction(SIGSEGV, &action, NULL) == -1)
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ELOG("Could not setup signal handler");
}