3abbffa493
There really is no need to source a defined variable from a linux header. The OOM-rank ranges from -1000 to 1000, so we can safely hardcode -1000, which is a sane thing to do given slock is suid and we don't want to play around too much here anyway. On another notice, let's not forget that this still is a shitty heuristic. The OOM-killer still can kill us (thus I also changed the wording in the error-message. We do not disable the OOM-killer, we're just hiding.
351 lines
8.2 KiB
C
351 lines
8.2 KiB
C
/* See LICENSE file for license details. */
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#define _XOPEN_SOURCE 500
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#if HAVE_SHADOW_H
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#include <shadow.h>
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#endif
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#include <ctype.h>
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#include <errno.h>
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#include <pwd.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <X11/extensions/Xrandr.h>
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#include <X11/keysym.h>
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#include <X11/Xlib.h>
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#include <X11/Xutil.h>
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#if HAVE_BSD_AUTH
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#include <login_cap.h>
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#include <bsd_auth.h>
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#endif
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enum {
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INIT,
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INPUT,
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FAILED,
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NUMCOLS
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};
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#include "config.h"
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typedef struct {
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int screen;
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Window root, win;
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Pixmap pmap;
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unsigned long colors[NUMCOLS];
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} Lock;
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static Lock **locks;
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static int nscreens;
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static Bool running = True;
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static Bool failure = False;
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static Bool rr;
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static int rrevbase;
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static int rrerrbase;
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static void
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die(const char *errstr, ...)
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{
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va_list ap;
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va_start(ap, errstr);
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vfprintf(stderr, errstr, ap);
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va_end(ap);
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exit(1);
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}
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#ifdef __linux__
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#include <fcntl.h>
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static void
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dontkillme(void)
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{
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int fd;
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fd = open("/proc/self/oom_score_adj", O_WRONLY);
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if (fd < 0 && errno == ENOENT) {
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return;
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}
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if (fd < 0 || write(fd, "-1000\n", (sizeof("-1000\n") - 1)) !=
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(sizeof("-1000\n") - 1) || close(fd) != 0) {
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die("can't tame the oom-killer. is suid or sgid set?\n");
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}
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}
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#endif
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#ifndef HAVE_BSD_AUTH
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/* only run as root */
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static const char *
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getpw(void)
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{
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const char *rval;
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struct passwd *pw;
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errno = 0;
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if (!(pw = getpwuid(getuid()))) {
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if (errno)
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die("slock: getpwuid: %s\n", strerror(errno));
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else
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die("slock: cannot retrieve password entry\n");
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}
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rval = pw->pw_passwd;
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#if HAVE_SHADOW_H
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if (rval[0] == 'x' && rval[1] == '\0') {
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struct spwd *sp;
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if (!(sp = getspnam(getenv("USER"))))
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die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
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rval = sp->sp_pwdp;
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}
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#endif
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/* drop privileges */
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if (geteuid() == 0 &&
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((getegid() != pw->pw_gid && setgid(pw->pw_gid) < 0) || setuid(pw->pw_uid) < 0))
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die("slock: cannot drop privileges\n");
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return rval;
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}
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#endif
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static void
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#ifdef HAVE_BSD_AUTH
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readpw(Display *dpy)
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#else
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readpw(Display *dpy, const char *pws)
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#endif
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{
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char buf[32], passwd[256];
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int num, screen;
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unsigned int len, color;
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KeySym ksym;
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XEvent ev;
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static int oldc = INIT;
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len = 0;
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running = True;
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/* As "slock" stands for "Simple X display locker", the DPMS settings
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* had been removed and you can set it with "xset" or some other
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* utility. This way the user can easily set a customized DPMS
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* timeout. */
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while (running && !XNextEvent(dpy, &ev)) {
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if (ev.type == KeyPress) {
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buf[0] = 0;
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num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
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if (IsKeypadKey(ksym)) {
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if (ksym == XK_KP_Enter)
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ksym = XK_Return;
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else if (ksym >= XK_KP_0 && ksym <= XK_KP_9)
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ksym = (ksym - XK_KP_0) + XK_0;
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}
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if (IsFunctionKey(ksym) ||
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IsKeypadKey(ksym) ||
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IsMiscFunctionKey(ksym) ||
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IsPFKey(ksym) ||
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IsPrivateKeypadKey(ksym))
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continue;
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switch (ksym) {
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case XK_Return:
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passwd[len] = 0;
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#ifdef HAVE_BSD_AUTH
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running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
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#else
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running = !!strcmp(crypt(passwd, pws), pws);
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#endif
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if (running) {
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XBell(dpy, 100);
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failure = True;
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}
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len = 0;
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break;
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case XK_Escape:
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len = 0;
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break;
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case XK_BackSpace:
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if (len)
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--len;
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break;
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default:
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if (num && !iscntrl((int)buf[0]) && (len + num < sizeof(passwd))) {
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memcpy(passwd + len, buf, num);
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len += num;
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}
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break;
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}
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color = len ? INPUT : (failure || failonclear ? FAILED : INIT);
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if (running && oldc != color) {
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for (screen = 0; screen < nscreens; screen++) {
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XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[color]);
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XClearWindow(dpy, locks[screen]->win);
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}
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oldc = color;
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}
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} else if (rr && ev.type == rrevbase + RRScreenChangeNotify) {
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XRRScreenChangeNotifyEvent *rre = (XRRScreenChangeNotifyEvent*)&ev;
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for (screen = 0; screen < nscreens; screen++) {
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if (locks[screen]->win == rre->window) {
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XResizeWindow(dpy, locks[screen]->win, rre->width, rre->height);
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XClearWindow(dpy, locks[screen]->win);
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}
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}
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} else for (screen = 0; screen < nscreens; screen++)
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XRaiseWindow(dpy, locks[screen]->win);
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}
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}
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static void
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unlockscreen(Display *dpy, Lock *lock)
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{
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if(dpy == NULL || lock == NULL)
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return;
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XUngrabPointer(dpy, CurrentTime);
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XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, NUMCOLS, 0);
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XFreePixmap(dpy, lock->pmap);
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XDestroyWindow(dpy, lock->win);
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free(lock);
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}
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static Lock *
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lockscreen(Display *dpy, int screen)
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{
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char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
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unsigned int len;
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int i;
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Lock *lock;
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XColor color, dummy;
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XSetWindowAttributes wa;
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Cursor invisible;
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if (!running || dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))
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return NULL;
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lock->screen = screen;
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lock->root = RootWindow(dpy, lock->screen);
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for (i = 0; i < NUMCOLS; i++) {
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XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), colorname[i], &color, &dummy);
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lock->colors[i] = color.pixel;
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}
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/* init */
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wa.override_redirect = 1;
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wa.background_pixel = lock->colors[INIT];
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lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
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0, DefaultDepth(dpy, lock->screen), CopyFromParent,
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DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
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lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
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invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
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XDefineCursor(dpy, lock->win, invisible);
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XMapRaised(dpy, lock->win);
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if (rr)
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XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
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/* Try to grab mouse pointer *and* keyboard, else fail the lock */
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for (len = 1000; len; len--) {
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if (XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
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GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
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break;
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usleep(1000);
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}
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if (!len) {
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fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
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} else {
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for (len = 1000; len; len--) {
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if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime) == GrabSuccess) {
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/* everything fine, we grabbed both inputs */
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XSelectInput(dpy, lock->root, SubstructureNotifyMask);
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return lock;
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}
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usleep(1000);
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}
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fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
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}
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/* grabbing one of the inputs failed */
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running = 0;
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unlockscreen(dpy, lock);
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return NULL;
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}
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static void
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usage(void)
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{
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fprintf(stderr, "usage: slock [-v|POST_LOCK_CMD]\n");
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exit(1);
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}
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int
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main(int argc, char **argv) {
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#ifndef HAVE_BSD_AUTH
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const char *pws;
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#endif
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Display *dpy;
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int screen;
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if ((argc == 2) && !strcmp("-v", argv[1]))
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die("slock-%s, © 2006-2016 slock engineers\n", VERSION);
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if ((argc == 2) && !strcmp("-h", argv[1]))
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usage();
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#ifdef __linux__
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dontkillme();
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#endif
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if (!getpwuid(getuid()))
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die("slock: no passwd entry for you\n");
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#ifndef HAVE_BSD_AUTH
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pws = getpw();
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#endif
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if (!(dpy = XOpenDisplay(0)))
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die("slock: cannot open display\n");
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rr = XRRQueryExtension(dpy, &rrevbase, &rrerrbase);
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/* Get the number of screens in display "dpy" and blank them all. */
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nscreens = ScreenCount(dpy);
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if (!(locks = malloc(sizeof(Lock*) * nscreens)))
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die("slock: malloc: %s\n", strerror(errno));
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int nlocks = 0;
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for (screen = 0; screen < nscreens; screen++) {
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if ((locks[screen] = lockscreen(dpy, screen)) != NULL)
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nlocks++;
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}
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XSync(dpy, False);
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/* Did we actually manage to lock something? */
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if (nlocks == 0) { /* nothing to protect */
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free(locks);
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XCloseDisplay(dpy);
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return 1;
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}
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if (argc >= 2 && fork() == 0) {
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if (dpy)
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close(ConnectionNumber(dpy));
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execvp(argv[1], argv+1);
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die("slock: execvp %s failed: %s\n", argv[1], strerror(errno));
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}
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/* Everything is now blank. Now wait for the correct password. */
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#ifdef HAVE_BSD_AUTH
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readpw(dpy);
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#else
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readpw(dpy, pws);
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#endif
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/* Password ok, unlock everything and quit. */
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for (screen = 0; screen < nscreens; screen++)
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unlockscreen(dpy, locks[screen]);
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free(locks);
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XCloseDisplay(dpy);
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return 0;
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}
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