diff options
Diffstat (limited to 'slock.c')
| -rw-r--r-- | slock.c | 395 |
1 files changed, 395 insertions, 0 deletions
@@ -0,0 +1,395 @@ +/* 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 "arg.h" +#include "util.h" + +char *argv0; + +enum { + INIT, + INPUT, + FAILED, + 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 num, screen, running, failure, oldc; + unsigned int len, color; + KeySym ksym; + XEvent ev; + + len = 0; + running = 1; + failure = 0; + oldc = INIT; + + 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; + default: + if (num && !iscntrl((int)buf[0]) && + (len + num < sizeof(passwd))) { + memcpy(passwd + len, buf, num); + len += num; + } + break; + } + color = len ? 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; +} |