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[slock.git] / slock.c
diff --git a/slock.c b/slock.c
index 3e2ab8f..2a3027e 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -6,6 +6,7 @@
 
 #include <ctype.h>
 #include <errno.h>
 
 #include <ctype.h>
 #include <errno.h>
+#include <grp.h>
 #include <pwd.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <pwd.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -18,11 +19,6 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
-#if HAVE_BSD_AUTH
-#include <login_cap.h>
-#include <bsd_auth.h>
-#endif
-
 #include "arg.h"
 #include "util.h"
 
 #include "arg.h"
 #include "util.h"
 
@@ -37,20 +33,18 @@ enum {
 
 #include "config.h"
 
 
 #include "config.h"
 
-typedef struct {
+struct lock {
        int screen;
        Window root, win;
        Pixmap pmap;
        unsigned long colors[NUMCOLS];
        int screen;
        Window root, win;
        Pixmap pmap;
        unsigned long colors[NUMCOLS];
-} Lock;
+};
 
 
-static Lock **locks;
-static int nscreens;
-static Bool running = True;
-static Bool failure = False;
-static Bool rr;
-static int rrevbase;
-static int rrerrbase;
+struct xrandr {
+       int active;
+       int evbase;
+       int errbase;
+};
 
 static void
 die(const char *errstr, ...)
 
 static void
 die(const char *errstr, ...)
@@ -65,78 +59,87 @@ die(const char *errstr, ...)
 
 #ifdef __linux__
 #include <fcntl.h>
 
 #ifdef __linux__
 #include <fcntl.h>
+#include <linux/oom.h>
 
 static void
 dontkillme(void)
 {
 
 static void
 dontkillme(void)
 {
-       int fd;
+       FILE *f;
+       const char oomfile[] = "/proc/self/oom_score_adj";
 
 
-       fd = open("/proc/self/oom_score_adj", O_WRONLY);
-       if (fd < 0 && errno == ENOENT) {
-               return;
+       if (!(f = fopen(oomfile, "w"))) {
+               if (errno == ENOENT)
+                       return;
+               die("slock: fopen %s: %s\n", oomfile, strerror(errno));
        }
        }
-       if (fd < 0 || write(fd, "-1000\n", (sizeof("-1000\n") - 1)) !=
-           (sizeof("-1000\n") - 1) || close(fd) != 0) {
-               die("can't tame the oom-killer. is suid or sgid set?\n");
+       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
 
        }
 }
 #endif
 
-#ifndef HAVE_BSD_AUTH
-/* only run as root */
 static const char *
 static const char *
-getpw(void)
+gethash(void)
 {
 {
-       const char *rval;
+       const char *hash;
        struct passwd *pw;
 
        struct passwd *pw;
 
+       /* Check if the current user has a password entry */
        errno = 0;
        if (!(pw = getpwuid(getuid()))) {
                if (errno)
        errno = 0;
        if (!(pw = getpwuid(getuid()))) {
                if (errno)
-                       die("getpwuid: %s\n", strerror(errno));
+                       die("slock: getpwuid: %s\n", strerror(errno));
                else
                else
-                       die("cannot retrieve password entry\n");
+                       die("slock: cannot retrieve password entry\n");
        }
        }
-       rval = pw->pw_passwd;
+       hash = pw->pw_passwd;
 
 #if HAVE_SHADOW_H
 
 #if HAVE_SHADOW_H
-       if (rval[0] == 'x' && rval[1] == '\0') {
+       if (hash[0] == 'x' && hash[1] == '\0') {
                struct spwd *sp;
                struct spwd *sp;
-               if (!(sp = getspnam(getenv("USER"))))
-                       die("cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
-               rval = sp->sp_pwdp;
+               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;
        }
        }
-#endif
+#else
+       if (hash[0] == '*' && hash[1] == '\0') {
+#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 */
 
 
-       /* drop privileges */
-       if (geteuid() == 0 &&
-           ((getegid() != pw->pw_gid && setgid(pw->pw_gid) < 0) || setuid(pw->pw_uid) < 0))
-               die("cannot drop privileges\n");
-       return rval;
+       return hash;
 }
 }
-#endif
 
 static void
 
 static void
-#ifdef HAVE_BSD_AUTH
-readpw(Display *dpy)
-#else
-readpw(Display *dpy, const char *pws)
-#endif
+readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
+       const char *hash)
 {
 {
-       char buf[32], passwd[256], *encrypted;
-       int num, screen;
+       XRRScreenChangeNotifyEvent *rre;
+       char buf[32], passwd[256], *inputhash;
+       int num, screen, running, failure;
        unsigned int len, color;
        KeySym ksym;
        XEvent ev;
        static int oldc = INIT;
 
        len = 0;
        unsigned int len, color;
        KeySym ksym;
        XEvent ev;
        static int oldc = INIT;
 
        len = 0;
-       running = True;
+       running = 1;
+       failure = 0;
 
 
-       /* As "slock" stands for "Simple X display locker", the DPMS settings
-        * had been removed and you can set it with "xset" or some other
-        * utility. This way the user can easily set a customized DPMS
-        * timeout. */
        while (running && !XNextEvent(dpy, &ev)) {
                if (ev.type == KeyPress) {
                        explicit_bzero(&buf, sizeof(buf));
        while (running && !XNextEvent(dpy, &ev)) {
                if (ev.type == KeyPress) {
                        explicit_bzero(&buf, sizeof(buf));
@@ -156,15 +159,11 @@ readpw(Display *dpy, const char *pws)
                        switch (ksym) {
                        case XK_Return:
                                passwd[len] = 0;
                        switch (ksym) {
                        case XK_Return:
                                passwd[len] = 0;
-#ifdef HAVE_BSD_AUTH
-                               running = !auth_userokay(getlogin(), NULL, "auth-slock", passwd);
-#else
                                errno = 0;
                                errno = 0;
-                               if (!(encrypted = crypt(passwd, pws)))
+                               if (!(inputhash = crypt(passwd, hash)))
                                        fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
                                else
                                        fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
                                else
-                                       running = !!strcmp(encrypted, pws);
-#endif
+                                       running = !!strcmp(inputhash, hash);
                                if (running) {
                                        XBell(dpy, 100);
                                        failure = True;
                                if (running) {
                                        XBell(dpy, 100);
                                        failure = True;
@@ -181,25 +180,29 @@ readpw(Display *dpy, const char *pws)
                                        passwd[len--] = 0;
                                break;
                        default:
                                        passwd[len--] = 0;
                                break;
                        default:
-                               if (num && !iscntrl((int)buf[0]) && (len + num < sizeof(passwd))) {
+                               if (num && !iscntrl((int)buf[0]) &&
+                                   (len + num < sizeof(passwd))) {
                                        memcpy(passwd + len, buf, num);
                                        len += num;
                                }
                                break;
                        }
                                        memcpy(passwd + len, buf, num);
                                        len += num;
                                }
                                break;
                        }
-                       color = len ? INPUT : (failure || failonclear ? FAILED : INIT);
+                       color = len ? INPUT : ((failure || failonclear) ? FAILED : INIT);
                        if (running && oldc != color) {
                                for (screen = 0; screen < nscreens; screen++) {
                        if (running && oldc != color) {
                                for (screen = 0; screen < nscreens; screen++) {
-                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[color]);
+                                       XSetWindowBackground(dpy,
+                                                            locks[screen]->win,
+                                                            locks[screen]->colors[color]);
                                        XClearWindow(dpy, locks[screen]->win);
                                }
                                oldc = color;
                        }
                                        XClearWindow(dpy, locks[screen]->win);
                                }
                                oldc = color;
                        }
-               } else if (rr && ev.type == rrevbase + RRScreenChangeNotify) {
-                       XRRScreenChangeNotifyEvent *rre = (XRRScreenChangeNotifyEvent*)&ev;
+               } else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
+                       rre = (XRRScreenChangeNotifyEvent*)&ev;
                        for (screen = 0; screen < nscreens; screen++) {
                                if (locks[screen]->win == rre->window) {
                        for (screen = 0; screen < nscreens; screen++) {
                                if (locks[screen]->win == rre->window) {
-                                       XResizeWindow(dpy, locks[screen]->win, rre->width, rre->height);
+                                       XResizeWindow(dpy, locks[screen]->win,
+                                                     rre->width, rre->height);
                                        XClearWindow(dpy, locks[screen]->win);
                                }
                        }
                                        XClearWindow(dpy, locks[screen]->win);
                                }
                        }
@@ -208,75 +211,82 @@ readpw(Display *dpy, const char *pws)
        }
 }
 
        }
 }
 
-static void
-unlockscreen(Display *dpy, Lock *lock)
-{
-       if(dpy == NULL || lock == NULL)
-               return;
-
-       XUngrabPointer(dpy, CurrentTime);
-       XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, NUMCOLS, 0);
-       XFreePixmap(dpy, lock->pmap);
-       XDestroyWindow(dpy, lock->win);
-
-       free(lock);
-}
-
-static Lock *
-lockscreen(Display *dpy, int screen)
+static struct lock *
+lockscreen(Display *dpy, struct xrandr *rr, int screen)
 {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
-       int i;
-       Lock *lock;
+       int i, ptgrab, kbgrab;
+       struct lock *lock;
        XColor color, dummy;
        XSetWindowAttributes wa;
        Cursor invisible;
 
        XColor color, dummy;
        XSetWindowAttributes wa;
        Cursor invisible;
 
-       if (!running || dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))
+       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++) {
                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);
+               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->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->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);
        lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
-       invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
+       invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
+                                       &color, &color, 0, 0);
        XDefineCursor(dpy, lock->win, invisible);
 
        XDefineCursor(dpy, lock->win, invisible);
 
-       /* Try to grab mouse pointer *and* keyboard, else fail the lock */
-       if (XGrabPointer(dpy, lock->root, False, ButtonPressMask |
-           ButtonReleaseMask | PointerMotionMask, GrabModeAsync, GrabModeAsync,
-           None, invisible, CurrentTime) != GrabSuccess) {
-               fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
-               running = 0;
-               unlockscreen(dpy, lock);
-               return NULL;
-       }
+       /* 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);
+               }
 
 
-       if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync,
-           CurrentTime) != GrabSuccess) {
-               fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
-               running = 0;
-               unlockscreen(dpy, lock);
-               return NULL;
-       }
+               /* 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);
 
 
-       XMapRaised(dpy, lock->win);
-       if (rr)
-               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);
+       }
 
 
-       XSelectInput(dpy, lock->root, SubstructureNotifyMask);
-       return lock;
+       /* 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
 }
 
 static void
@@ -287,11 +297,15 @@ usage(void)
 
 int
 main(int argc, char **argv) {
 
 int
 main(int argc, char **argv) {
-#ifndef HAVE_BSD_AUTH
-       const char *pws;
-#endif
+       struct xrandr rr;
+       struct lock **locks;
+       struct passwd *pwd;
+       struct group *grp;
+       uid_t duid;
+       gid_t dgid;
+       const char *hash;
        Display *dpy;
        Display *dpy;
-       int s, nlocks;
+       int s, nlocks, nscreens;
 
        ARGBEGIN {
        case 'v':
 
        ARGBEGIN {
        case 'v':
@@ -301,81 +315,73 @@ main(int argc, char **argv) {
                usage();
        } ARGEND
 
                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
 
 #ifdef __linux__
        dontkillme();
 #endif
 
-       /* Check if the current user has a password entry */
+       hash = gethash();
        errno = 0;
        errno = 0;
-       if (!getpwuid(getuid())) {
-               if (errno == 0)
-                       die("slock: no password entry for current user\n");
-               else
-                       die("slock: getpwuid: %s\n", strerror(errno));
-       }
-
-#ifndef HAVE_BSD_AUTH
-       pws = getpw();
-       if (strlen(pws) < 2)
-               die("slock: failed to get user password hash.\n");
-#endif
+       if (!crypt("", hash))
+               die("slock: crypt: %s\n", strerror(errno));
 
        if (!(dpy = XOpenDisplay(NULL)))
                die("slock: cannot open display\n");
 
 
        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 */
        /* check for Xrandr support */
-       rr = XRRQueryExtension(dpy, &rrevbase, &rrerrbase);
+       rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
 
        /* get number of screens in display "dpy" and blank them */
        nscreens = ScreenCount(dpy);
 
        /* get number of screens in display "dpy" and blank them */
        nscreens = ScreenCount(dpy);
-       if (!(locks = malloc(sizeof(Lock *) * nscreens))) {
-               XCloseDisplay(dpy);
+       if (!(locks = calloc(nscreens, sizeof(struct lock *))))
                die("slock: out of memory\n");
                die("slock: out of memory\n");
-       }
        for (nlocks = 0, s = 0; s < nscreens; s++) {
        for (nlocks = 0, s = 0; s < nscreens; s++) {
-               if ((locks[s] = lockscreen(dpy, s)) != NULL)
+               if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL)
                        nlocks++;
                        nlocks++;
+               else
+                       break;
        }
        XSync(dpy, 0);
 
        }
        XSync(dpy, 0);
 
-       /* did we actually manage to lock anything? */
-       if (nlocks == 0) {
-               /* nothing to protect */
-               free(locks);
-               XCloseDisplay(dpy);
+       /* did we manage to lock everything? */
+       if (nlocks != nscreens)
                return 1;
                return 1;
-       }
 
        /* run post-lock command */
        if (argc > 0) {
                switch (fork()) {
                case -1:
 
        /* run post-lock command */
        if (argc > 0) {
                switch (fork()) {
                case -1:
-                       free(locks);
-                       XCloseDisplay(dpy);
                        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);
                        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));
+                       fprintf(stderr, "slock: execvp %s: %s\n", argv[0], strerror(errno));
                        _exit(1);
                }
        }
 
        /* everything is now blank. Wait for the correct password */
                        _exit(1);
                }
        }
 
        /* everything is now blank. Wait for the correct password */
-#ifdef HAVE_BSD_AUTH
-       readpw(dpy);
-#else
-       readpw(dpy, pws);
-#endif
-
-       /* password ok, unlock everything and quit */
-       for (s = 0; s < nscreens; s++)
-               unlockscreen(dpy, locks[s]);
-
-       free(locks);
-       XCloseDisplay(dpy);
+       readpw(dpy, &rr, locks, nscreens, hash);
 
        return 0;
 }
 
        return 0;
 }