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/* See LICENSE file for license details. */
#define _XOPEN_SOURCE 500
#if HAVE_SHADOW_H
#include <shadow.h>
#endif
#include <ctype.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <X11/extensions/Xrandr.h>
#include <X11/keysym.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/XKBlib.h>
#include "arg.h"
#include "util.h"
char *argv0;
enum {
INIT,
INPUT,
FAILED,
CAPS,
NUMCOLS
};
struct lock {
int screen;
Window root, win;
Pixmap pmap;
unsigned long colors[NUMCOLS];
};
struct xrandr {
int active;
int evbase;
int errbase;
};
#include "config.h"
static void
die(const char *errstr, ...)
{
va_list ap;
va_start(ap, errstr);
vfprintf(stderr, errstr, ap);
va_end(ap);
exit(1);
}
#ifdef __linux__
#include <fcntl.h>
#include <linux/oom.h>
static void
dontkillme(void)
{
FILE *f;
const char oomfile[] = "/proc/self/oom_score_adj";
if (!(f = fopen(oomfile, "w"))) {
if (errno == ENOENT)
return;
die("slock: fopen %s: %s\n", oomfile, strerror(errno));
}
fprintf(f, "%d", OOM_SCORE_ADJ_MIN);
if (fclose(f)) {
if (errno == EACCES)
die("slock: unable to disable OOM killer. "
"Make sure to suid or sgid slock.\n");
else
die("slock: fclose %s: %s\n", oomfile, strerror(errno));
}
}
#endif
static const char *
gethash(void)
{
const char *hash;
struct passwd *pw;
/* Check if the current user has a password entry */
errno = 0;
if (!(pw = getpwuid(getuid()))) {
if (errno)
die("slock: getpwuid: %s\n", strerror(errno));
else
die("slock: cannot retrieve password entry\n");
}
hash = pw->pw_passwd;
#if HAVE_SHADOW_H
if (!strcmp(hash, "x")) {
struct spwd *sp;
if (!(sp = getspnam(pw->pw_name)))
die("slock: getspnam: cannot retrieve shadow entry. "
"Make sure to suid or sgid slock.\n");
hash = sp->sp_pwdp;
}
#else
if (!strcmp(hash, "*")) {
#ifdef __OpenBSD__
if (!(pw = getpwuid_shadow(getuid())))
die("slock: getpwnam_shadow: cannot retrieve shadow entry. "
"Make sure to suid or sgid slock.\n");
hash = pw->pw_passwd;
#else
die("slock: getpwuid: cannot retrieve shadow entry. "
"Make sure to suid or sgid slock.\n");
#endif /* __OpenBSD__ */
}
#endif /* HAVE_SHADOW_H */
return hash;
}
static void
readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
const char *hash)
{
XRRScreenChangeNotifyEvent *rre;
char buf[32], passwd[256], *inputhash;
int caps, num, screen, running, failure, oldc;
unsigned int len, color, indicators;
KeySym ksym;
XEvent ev;
len = 0;
caps = 0;
running = 1;
failure = 0;
oldc = INIT;
if (!XkbGetIndicatorState(dpy, XkbUseCoreKbd, &indicators))
caps = indicators & 1;
while (running && !XNextEvent(dpy, &ev)) {
if (ev.type == KeyPress) {
explicit_bzero(&buf, sizeof(buf));
num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
if (IsKeypadKey(ksym)) {
if (ksym == XK_KP_Enter)
ksym = XK_Return;
else if (ksym >= XK_KP_0 && ksym <= XK_KP_9)
ksym = (ksym - XK_KP_0) + XK_0;
}
if (IsFunctionKey(ksym) ||
IsKeypadKey(ksym) ||
IsMiscFunctionKey(ksym) ||
IsPFKey(ksym) ||
IsPrivateKeypadKey(ksym))
continue;
switch (ksym) {
case XK_Return:
passwd[len] = '\0';
errno = 0;
if (!(inputhash = crypt(passwd, hash)))
fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
else
running = !!strcmp(inputhash, hash);
if (running) {
XBell(dpy, 100);
failure = 1;
}
explicit_bzero(&passwd, sizeof(passwd));
len = 0;
break;
case XK_Escape:
explicit_bzero(&passwd, sizeof(passwd));
len = 0;
break;
case XK_BackSpace:
if (len)
passwd[--len] = '\0';
break;
case XK_Caps_Lock:
caps = !caps;
break;
default:
if (num && !iscntrl((int)buf[0]) &&
(len + num < sizeof(passwd))) {
memcpy(passwd + len, buf, num);
len += num;
}
break;
}
color = len ? (caps ? CAPS : INPUT) : (failure || failonclear ? FAILED : INIT);
if (running && oldc != color) {
for (screen = 0; screen < nscreens; screen++) {
XSetWindowBackground(dpy,
locks[screen]->win,
locks[screen]->colors[color]);
XClearWindow(dpy, locks[screen]->win);
}
oldc = color;
}
} else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
rre = (XRRScreenChangeNotifyEvent*)&ev;
for (screen = 0; screen < nscreens; screen++) {
if (locks[screen]->win == rre->window) {
if (rre->rotation == RR_Rotate_90 ||
rre->rotation == RR_Rotate_270)
XResizeWindow(dpy, locks[screen]->win,
rre->height, rre->width);
else
XResizeWindow(dpy, locks[screen]->win,
rre->width, rre->height);
XClearWindow(dpy, locks[screen]->win);
break;
}
}
} else {
for (screen = 0; screen < nscreens; screen++)
XRaiseWindow(dpy, locks[screen]->win);
}
}
}
static struct lock *
lockscreen(Display *dpy, struct xrandr *rr, int screen)
{
char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
int i, ptgrab, kbgrab;
struct lock *lock;
XColor color, dummy;
XSetWindowAttributes wa;
Cursor invisible;
if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(struct lock))))
return NULL;
lock->screen = screen;
lock->root = RootWindow(dpy, lock->screen);
for (i = 0; i < NUMCOLS; i++) {
XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen),
colorname[i], &color, &dummy);
lock->colors[i] = color.pixel;
}
/* init */
wa.override_redirect = 1;
wa.background_pixel = lock->colors[INIT];
lock->win = XCreateWindow(dpy, lock->root, 0, 0,
DisplayWidth(dpy, lock->screen),
DisplayHeight(dpy, lock->screen),
0, DefaultDepth(dpy, lock->screen),
CopyFromParent,
DefaultVisual(dpy, lock->screen),
CWOverrideRedirect | CWBackPixel, &wa);
lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
&color, &color, 0, 0);
XDefineCursor(dpy, lock->win, invisible);
/* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
if (ptgrab != GrabSuccess) {
ptgrab = XGrabPointer(dpy, lock->root, False,
ButtonPressMask | ButtonReleaseMask |
PointerMotionMask, GrabModeAsync,
GrabModeAsync, None, invisible, CurrentTime);
}
if (kbgrab != GrabSuccess) {
kbgrab = XGrabKeyboard(dpy, lock->root, True,
GrabModeAsync, GrabModeAsync, CurrentTime);
}
/* input is grabbed: we can lock the screen */
if (ptgrab == GrabSuccess && kbgrab == GrabSuccess) {
XMapRaised(dpy, lock->win);
if (rr->active)
XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
XSelectInput(dpy, lock->root, SubstructureNotifyMask);
return lock;
}
/* retry on AlreadyGrabbed but fail on other errors */
if ((ptgrab != AlreadyGrabbed && ptgrab != GrabSuccess) ||
(kbgrab != AlreadyGrabbed && kbgrab != GrabSuccess))
break;
usleep(100000);
}
/* we couldn't grab all input: fail out */
if (ptgrab != GrabSuccess)
fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n",
screen);
if (kbgrab != GrabSuccess)
fprintf(stderr, "slock: unable to grab keyboard for screen %d\n",
screen);
return NULL;
}
static void
usage(void)
{
die("usage: slock [-v] [cmd [arg ...]]\n");
}
int
main(int argc, char **argv) {
struct xrandr rr;
struct lock **locks;
struct passwd *pwd;
struct group *grp;
uid_t duid;
gid_t dgid;
const char *hash;
Display *dpy;
int s, nlocks, nscreens;
ARGBEGIN {
case 'v':
fprintf(stderr, "slock-"VERSION"\n");
return 0;
default:
usage();
} ARGEND
/* validate drop-user and -group */
errno = 0;
if (!(pwd = getpwnam(user)))
die("slock: getpwnam %s: %s\n", user,
errno ? strerror(errno) : "user entry not found");
duid = pwd->pw_uid;
errno = 0;
if (!(grp = getgrnam(group)))
die("slock: getgrnam %s: %s\n", group,
errno ? strerror(errno) : "group entry not found");
dgid = grp->gr_gid;
#ifdef __linux__
dontkillme();
#endif
hash = gethash();
errno = 0;
if (!crypt("", hash))
die("slock: crypt: %s\n", strerror(errno));
if (!(dpy = XOpenDisplay(NULL)))
die("slock: cannot open display\n");
/* drop privileges */
if (setgroups(0, NULL) < 0)
die("slock: setgroups: %s\n", strerror(errno));
if (setgid(dgid) < 0)
die("slock: setgid: %s\n", strerror(errno));
if (setuid(duid) < 0)
die("slock: setuid: %s\n", strerror(errno));
/* check for Xrandr support */
rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
/* get number of screens in display "dpy" and blank them */
nscreens = ScreenCount(dpy);
if (!(locks = calloc(nscreens, sizeof(struct lock *))))
die("slock: out of memory\n");
for (nlocks = 0, s = 0; s < nscreens; s++) {
if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL)
nlocks++;
else
break;
}
XSync(dpy, 0);
/* did we manage to lock everything? */
if (nlocks != nscreens)
return 1;
/* run post-lock command */
if (argc > 0) {
switch (fork()) {
case -1:
die("slock: fork failed: %s\n", strerror(errno));
case 0:
if (close(ConnectionNumber(dpy)) < 0)
die("slock: close: %s\n", strerror(errno));
execvp(argv[0], argv);
fprintf(stderr, "slock: execvp %s: %s\n", argv[0], strerror(errno));
_exit(1);
}
}
/* everything is now blank. Wait for the correct password */
readpw(dpy, &rr, locks, nscreens, hash);
return 0;
}