gri3-wm/src/sighandler.c

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/*
* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
* © 2009 Michael Stapelberg and contributors (see also: LICENSE)
*
*/
#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>
typedef struct dialog_t {
xcb_window_t id;
xcb_colormap_t colormap;
Rect dims;
surface_t surface;
TAILQ_ENTRY(dialog_t)
dialogs;
} dialog_t;
static TAILQ_HEAD(dialogs_head, dialog_t) dialogs = TAILQ_HEAD_INITIALIZER(dialogs);
static int raised_signal;
static int backtrace_done = 0;
static int sighandler_backtrace(void);
static void sighandler_setup(void);
static void sighandler_create_dialogs(void);
static void sighandler_destroy_dialogs(void);
static void sighandler_handle_expose(void);
static void sighandler_draw_dialog(dialog_t *dialog);
static void sighandler_handle_key_press(xcb_key_press_event_t *event);
static i3String *message_intro;
static i3String *message_intro2;
static i3String *message_option_backtrace;
static i3String *message_option_restart;
static i3String *message_option_forget;
static int dialog_width;
static int dialog_height;
static int border_width = 2;
static int margin = 4;
/*
* Attach gdb to pid_parent and dump a backtrace to i3-backtrace.$pid in the
* tmpdir
*/
static int sighandler_backtrace(void) {
char *tmpdir = getenv("TMPDIR");
if (tmpdir == NULL)
tmpdir = "/tmp";
pid_t pid_parent = getpid();
char *filename = NULL;
int suffix = 0;
/* 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 (path_exists(filename));
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];
if (pipe(stdin_pipe) == -1) {
ELOG("Failed to init stdin_pipe\n");
return -1;
}
if (pipe(stdout_pipe) == -1) {
ELOG("Failed to init stdout_pipe\n");
return -1;
}
/* 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
* https://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(EXIT_FAILURE);
}
int status = 0;
waitpid(pid_gdb, &status, 0);
/* see if the backtrace was successful or not */
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
DLOG("GDB did not run properly\n");
return -1;
} else if (!path_exists(filename)) {
DLOG("GDB executed successfully, but no backtrace was generated\n");
return -1;
}
return 1;
}
static void sighandler_setup(void) {
border_width = logical_px(border_width);
margin = logical_px(margin);
int num_lines = 5;
message_intro = i3string_from_utf8("i3 has just crashed. Please report a bug for this.");
message_intro2 = i3string_from_utf8("To debug this problem, you can either attach gdb or choose from the following options:");
message_option_backtrace = i3string_from_utf8("- 'b' to save a backtrace (requires gdb)");
message_option_restart = i3string_from_utf8("- 'r' to restart i3 in-place");
message_option_forget = i3string_from_utf8("- 'f' to forget the previous layout and restart i3");
int width_longest_message = predict_text_width(message_intro2);
dialog_width = width_longest_message + 2 * border_width + 2 * margin;
dialog_height = num_lines * config.font.height + 2 * border_width + 2 * margin;
}
static void sighandler_create_dialogs(void) {
Output *output;
TAILQ_FOREACH (output, &outputs, outputs) {
if (!output->active) {
continue;
}
dialog_t *dialog = scalloc(1, sizeof(struct dialog_t));
TAILQ_INSERT_TAIL(&dialogs, dialog, dialogs);
xcb_visualid_t visual = get_visualid_by_depth(root_depth);
dialog->colormap = xcb_generate_id(conn);
xcb_create_colormap(conn, XCB_COLORMAP_ALLOC_NONE, dialog->colormap, root, visual);
uint32_t mask = 0;
uint32_t values[4];
int i = 0;
/* Needs to be set in the case of a 32-bit root depth. */
mask |= XCB_CW_BACK_PIXEL;
values[i++] = root_screen->black_pixel;
/* Needs to be set in the case of a 32-bit root depth. */
mask |= XCB_CW_BORDER_PIXEL;
values[i++] = root_screen->black_pixel;
mask |= XCB_CW_OVERRIDE_REDIRECT;
values[i++] = 1;
/* Needs to be set in the case of a 32-bit root depth. */
mask |= XCB_CW_COLORMAP;
values[i++] = dialog->colormap;
dialog->dims.x = output->rect.x + (output->rect.width / 2);
dialog->dims.y = output->rect.y + (output->rect.height / 2);
dialog->dims.width = dialog_width;
dialog->dims.height = dialog_height;
/* Make sure the dialog is centered. */
dialog->dims.x -= dialog->dims.width / 2;
dialog->dims.y -= dialog->dims.height / 2;
dialog->id = create_window(conn, dialog->dims, root_depth, visual,
XCB_WINDOW_CLASS_INPUT_OUTPUT, XCURSOR_CURSOR_POINTER,
true, mask, values);
draw_util_surface_init(conn, &(dialog->surface), dialog->id, get_visualtype_by_id(visual),
dialog->dims.width, dialog->dims.height);
xcb_grab_keyboard(conn, false, dialog->id, XCB_CURRENT_TIME, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
/* Confine the pointer to the crash dialog. */
xcb_grab_pointer(conn, false, dialog->id, XCB_NONE, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC, dialog->id,
XCB_NONE, XCB_CURRENT_TIME);
}
sighandler_handle_expose();
xcb_flush(conn);
}
static void sighandler_destroy_dialogs(void) {
while (!TAILQ_EMPTY(&dialogs)) {
dialog_t *dialog = TAILQ_FIRST(&dialogs);
xcb_free_colormap(conn, dialog->colormap);
draw_util_surface_free(conn, &(dialog->surface));
xcb_destroy_window(conn, dialog->id);
TAILQ_REMOVE(&dialogs, dialog, dialogs);
free(dialog);
}
xcb_flush(conn);
}
static void sighandler_handle_expose(void) {
dialog_t *current;
TAILQ_FOREACH (current, &dialogs, dialogs) {
sighandler_draw_dialog(current);
}
xcb_flush(conn);
}
static void sighandler_draw_dialog(dialog_t *dialog) {
const color_t black = draw_util_hex_to_color("#000000");
const color_t white = draw_util_hex_to_color("#FFFFFF");
const color_t red = draw_util_hex_to_color("#FF0000");
/* Start with a clean slate and draw a red border. */
draw_util_clear_surface(&(dialog->surface), red);
draw_util_rectangle(&(dialog->surface), black, border_width, border_width,
dialog->dims.width - 2 * border_width, dialog->dims.height - 2 * border_width);
int y = border_width + margin;
const int x = border_width + margin;
const int max_width = dialog->dims.width - 2 * x;
draw_util_text(message_intro, &(dialog->surface), white, black, x, y, max_width);
y += config.font.height;
draw_util_text(message_intro2, &(dialog->surface), white, black, x, y, max_width);
y += config.font.height;
char *bt_color = "#FFFFFF";
if (backtrace_done < 0) {
bt_color = "#AA0000";
} else if (backtrace_done > 0) {
bt_color = "#00AA00";
}
draw_util_text(message_option_backtrace, &(dialog->surface), draw_util_hex_to_color(bt_color), black, x, y, max_width);
y += config.font.height;
draw_util_text(message_option_restart, &(dialog->surface), white, black, x, y, max_width);
y += config.font.height;
draw_util_text(message_option_forget, &(dialog->surface), white, black, x, y, max_width);
y += config.font.height;
}
static void sighandler_handle_key_press(xcb_key_press_event_t *event) {
uint16_t state = event->state;
/* Apparently, 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;
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 = sighandler_backtrace();
sighandler_handle_expose();
} else if (sym == 'r') {
sighandler_destroy_dialogs();
i3_restart(false);
} else if (sym == 'f') {
sighandler_destroy_dialogs();
i3_restart(true);
}
}
static 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;
action.sa_flags = 0;
sigemptyset(&action.sa_mask);
sigaction(sig, &action, NULL);
raised_signal = sig;
sighandler_setup();
sighandler_create_dialogs();
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);
switch (type) {
case XCB_KEY_PRESS:
sighandler_handle_key_press((xcb_key_press_event_t *)event);
break;
case XCB_EXPOSE:
if (((xcb_expose_event_t *)event)->count == 0) {
sighandler_handle_expose();
}
break;
}
free(event);
}
}
/*
* Configured a signal handler to gracefully handle crashes and allow the user
* to generate a backtrace and rescue their session.
*
*/
void setup_signal_handler(void) {
struct sigaction action;
action.sa_sigaction = handle_signal;
action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
sigemptyset(&action.sa_mask);
/* Catch all signals with default action "Core", see signal(7) */
if (sigaction(SIGQUIT, &action, NULL) == -1 ||
sigaction(SIGILL, &action, NULL) == -1 ||
sigaction(SIGABRT, &action, NULL) == -1 ||
sigaction(SIGFPE, &action, NULL) == -1 ||
sigaction(SIGSEGV, &action, NULL) == -1)
ELOG("Could not setup signal handler.\n");
}