/* [ʞ] safekill.c <c.hale.su/lexi/util>
* ~ lexi hale <lexi@hale.su>
* $ cc -Ofast safekill.c -lX11 -osafekill
* © affero general public license
* a utility to make it harder to accidentally nuke
* important windows on i3wm or whatever.
TODO add option to run as daemon that listens for
key chords, for wms that don't have built-in
support for user keybindings */
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
typedef enum { false, true } bool;
Display *display;
Atom xvital;
bool isvital(Window w) {
unsigned char* value;
int _i; long _l;
Atom type;
XGetWindowProperty(display,w, xvital, 0,1,False,xvital,
&type,&_i,&_l,&_l, &value);
return type != None;
}
void killwin(Window w) {
XEvent ev;
long mask = SubstructureRedirectMask | SubstructureNotifyMask;
ev.xclient.type = ClientMessage;
ev.xclient.serial = 0;
ev.xclient.send_event = True;
ev.xclient.message_type = XInternAtom(display, "_NET_CLOSE_WINDOW", False);
ev.xclient.window = w;
ev.xclient.format = 32;
if(!XSendEvent(display, DefaultRootWindow(display), False, mask, &ev)) {
char* fallback = getenv("k_safekill_fallback");
bool nofb = (*fallback == '0' && fallback[1] == 0);
fprintf(stderr,"\x1b[1mwarning:\x1b[m cannot send _NET_CLOSE_WINDOW event to root window; is your window manager okay?");
if (nofb) {
fprintf(stderr,"\n");
} else {
fprintf(stderr," falling back to XDestroyWindow, but this may wreck your shit - lots of multi-win apps do *not* like it.\n");
XDestroyWindow(display,w);
}
}
}
bool isnum(const char* str) {
// is the string passed something strtoul can interpret as a
// number? decimal, hex, or octal?
if (*str == '0' && str[1] == 0) return true;
enum { hex, dec, oct } mode;
if (*str == '0' && str[1] == 'x') mode = hex, str += 2;
else if (*str == '0') mode = oct, str += 1;
else mode = dec;
bool first = true;
eval: if(*str == 0) return !first;
first = false;
if(*str >= '0' && *str <= '7') {
++ str; goto eval;
} else if ((mode == dec || mode == hex) && *str >= '0' && *str <= '9') {
++ str; goto eval;
} else if (mode == hex && (
(*str >= 'a' && *str <= 'f') ||
(*str >= 'A' && *str <= 'F'))) {
++ str; goto eval;
} else return false;
}
int bad(Display* d, XErrorEvent* e) {
printf("\x1b[1merror:\x1b[m no such window\n");
exit(1);
}
int main(const int argc, const char** argv) {
Window focus;
int revert;
bool active;
enum { vitalize, devitalize, hardkill, softkill } op;
const char* winp = argv[2];
if (argc > 3) goto usage; // nope
if (argc == 1) // no parameters, implied softkill on active win
op = softkill, active = true;
else {
if (argc == 2) { // single argument; what kind is it?
if (isnum(argv[1])) { // single numeric argument = win id
active = false; // window is specified for us
op = softkill; // implied softkill
winp = argv[1]; // interpret argv[1] as window id
goto go_go_go; // skip the rest of this nonsense;
// we already know there's no switch
} else {
active = true; // no number passed, so it's either a
// switch with an implied active window or bad syntax
// now we need to figure out which
}
} else if (argc == 3) active = false; // win id AND opt
// determine mission parameters
if (argv[1][0] == '-' && argv[1][2] == 0) { // opt is short switch
switch (argv[1][1]) { // opt char
// make window mission-critical
case 'v': op = vitalize; break;
// make window acceptable loss
case 'c': op = devitalize; break;
// liquidate by any means necessary
case 'q': op = hardkill; break;
// with all due respect sir what the fuck
default: goto usage;
}
} else goto usage;
}
go_go_go:
display = XOpenDisplay(NULL);
xvital = XInternAtom(display, "_k_vital", False);
XSetErrorHandler(bad);
if (active) {
XGetInputFocus(display, &focus, &revert);
} else {
unsigned long temp = strtoul(winp, NULL, 0);
if (errno == EINVAL || errno == ERANGE) goto usage;
if (temp == 0) goto usage;
focus = (Window)temp;
}
if(op == hardkill) {
killwin(focus);
XSync(display,false);
return 0;
}
char* v;
if(isvital(focus)) {
if (op == vitalize) return 0; // nothing need be done
else if (op == devitalize) {
XDeleteProperty(display, focus, xvital);
XSync(display,false);
} else if (op == softkill) {
fprintf(stderr, "softkill forbidden\n");
return 1; // ACCESS DENIED
}
} else {
if (op == vitalize) {
char* yes="\01"; //arbitrary
XChangeProperty(display,focus, xvital,xvital,8,PropModeReplace, yes, 1);
XSync(display,false);
} else if (op == devitalize) return 0;
else if (op == softkill) {
// ice that motherfucker
killwin(focus);
XSync(display,false);
return 3;
}
}
return 0;
usage:
#define info "\x1b[34m-- "
#define param "\x1b[32m"
#define eol "\x1b[m\n"
#define bold "\x1b[1m"
#define nl " "
fprintf(stderr, bold "usage:\x1b[0m %s " " " info "kill active window if non-vital" eol
nl "%1$s -v " param "[id] " info "make [id] or active window vital" eol
nl "%1$s -c " param "[id] " info "clear vital flag on [id] or active window" eol
nl "%1$s -q " param "[id] " info "'emergency' kill w/o reference to vital flag" eol,
argv[0]);
return 1;
}