Only check errno if getpwuid() fails

[slock.git] / slock.c

diff --git a/slock.c b/slock.c
index 2dce109..399386b 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -1,3 +1,4 @@
+

 /* See LICENSE file for license details. */
 #define _XOPEN_SOURCE 500
 #if HAVE_SHADOW_H
 /* See LICENSE file for license details. */
 #define _XOPEN_SOURCE 500
 #if HAVE_SHADOW_H


@@ -22,52 +23,74 @@
 #include <bsd_auth.h>
 #endif
 
 #include <bsd_auth.h>
 #endif
 

-struct st_lock {
+typedef struct {

        int screen;
        int screen;

-       Window root, w;
+       Window root, win;

        Pixmap pmap;
        Pixmap pmap;

-};
+       unsigned long colors[2];
+} Lock;

 
 

-extern const char *__progname;
+static Lock **locks;
+static int nscreens;
+static Bool running = True;

 
 static void
 die(const char *errstr, ...) {
        va_list ap;
 
 
 static void
 die(const char *errstr, ...) {
        va_list ap;
 

-       fprintf(stderr, "%s: ", __progname);

        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);
        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);

-       fprintf(stderr, "\n");
-       fflush(stderr);
-

        exit(EXIT_FAILURE);
 }
 
        exit(EXIT_FAILURE);
 }
 

+#ifdef __linux__
+#include <fcntl.h>
+
+static void
+dontkillme(void) {
+       int fd;
+
+       fd = open("/proc/self/oom_score_adj", O_WRONLY);
+       if (fd < 0 && errno == ENOENT)
+               return;
+       if (fd < 0 || write(fd, "-1000\n", 6) != 6 || close(fd) != 0)
+               die("cannot disable the out-of-memory killer for this process\n");
+}
+#endif
+

 #ifndef HAVE_BSD_AUTH
 static const char *
 getpw(void) { /* only run as root */
        const char *rval;
        struct passwd *pw;
 
 #ifndef HAVE_BSD_AUTH
 static const char *
 getpw(void) { /* only run as root */
        const char *rval;
        struct passwd *pw;
 

-       if(geteuid() != 0)
-               die("cannot retrieve password entry (make sure to suid slock)");
+       errno = 0;

        pw = getpwuid(getuid());
        pw = getpwuid(getuid());

+       if (!pw) {
+               if (errno)
+                       die("slock: getpwuid: %s\n", strerror(errno));
+               else
+                       die("slock: cannot retrieve password entry (make sure to suid or sgid slock)\n");
+       }

        endpwent();
        rval =  pw->pw_passwd;
 
 #if HAVE_SHADOW_H
        endpwent();
        rval =  pw->pw_passwd;
 
 #if HAVE_SHADOW_H

-       {
+       if (rval[0] == 'x' && rval[1] == '\0') {

                struct spwd *sp;
                sp = getspnam(getenv("USER"));
                struct spwd *sp;
                sp = getspnam(getenv("USER"));

+               if(!sp)
+                       die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");

                endspent();
                rval = sp->sp_pwdp;
        }
 #endif
 
        /* drop privileges */
                endspent();
                rval = sp->sp_pwdp;
        }
 #endif
 
        /* drop privileges */

-       if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
-               die("cannot drop privileges");
+       if (geteuid() == 0
+          && ((getegid() != pw->pw_gid && setgid(pw->pw_gid) < 0) || setuid(pw->pw_uid) < 0))
+               die("slock: cannot drop privileges\n");

        return rval;
 }
 #endif
        return rval;
 }
 #endif


@@ -80,21 +103,18 @@ readpw(Display *dpy, const char *pws)
 #endif
 {
        char buf[32], passwd[256];
 #endif
 {
        char buf[32], passwd[256];

-       int num;
-
-       unsigned int len;
-       Bool running = True;
+       int num, screen;
+       unsigned int len, llen;

        KeySym ksym;
        XEvent ev;
 
        KeySym ksym;
        XEvent ev;
 

-       len = 0;
+       len = llen = 0;

        running = True;
 
        /* 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. */
        running = True;
 
        /* 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) {
                        buf[0] = 0;
        while(running && !XNextEvent(dpy, &ev)) {
                if(ev.type == KeyPress) {
                        buf[0] = 0;


@@ -115,9 +135,9 @@ readpw(Display *dpy, const char *pws)
 #ifdef HAVE_BSD_AUTH
                                running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 #else
 #ifdef HAVE_BSD_AUTH
                                running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 #else

-                               running = strcmp(crypt(passwd, pws), pws);
+                               running = !!strcmp(crypt(passwd, pws), pws);

 #endif
 #endif

-                               if (running != 0)
+                               if(running)

                                        XBell(dpy, 100);
                                len = 0;
                                break;
                                        XBell(dpy, 100);
                                len = 0;
                                break;


@@ -129,43 +149,57 @@ readpw(Display *dpy, const char *pws)
                                        --len;
                                break;
                        default:
                                        --len;
                                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;
                        }

+                       if(llen == 0 && len != 0) {
+                               for(screen = 0; screen < nscreens; screen++) {
+                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[1]);
+                                       XClearWindow(dpy, locks[screen]->win);
+                               }
+                       } else if(llen != 0 && len == 0) {
+                               for(screen = 0; screen < nscreens; screen++) {
+                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[0]);
+                                       XClearWindow(dpy, locks[screen]->win);
+                               }
+                       }
+                       llen = len;

                }
                }

+               else for(screen = 0; screen < nscreens; screen++)
+                       XRaiseWindow(dpy, locks[screen]->win);

        }
 }
 
 static void
        }
 }
 
 static void

-unlockscreen(Display *dpy, struct st_lock *lock) {
-       if (dpy == NULL || lock == NULL)
+unlockscreen(Display *dpy, Lock *lock) {
+       if(dpy == NULL || lock == NULL)

                return;
 
        XUngrabPointer(dpy, CurrentTime);
                return;
 
        XUngrabPointer(dpy, CurrentTime);

+       XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, 2, 0);

        XFreePixmap(dpy, lock->pmap);
        XFreePixmap(dpy, lock->pmap);

-       XDestroyWindow(dpy, lock->w);
+       XDestroyWindow(dpy, lock->win);

 
        free(lock);
 }
 
 
        free(lock);
 }
 

-static struct st_lock *
+static Lock *

 lockscreen(Display *dpy, int screen) {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
        unsigned int len;
 lockscreen(Display *dpy, int screen) {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
        unsigned int len;

-       struct st_lock *lock;
-       Bool running = True;
-       XColor black, dummy;
+       Lock *lock;
+       XColor color, dummy;

        XSetWindowAttributes wa;
        Cursor invisible;
 
        XSetWindowAttributes wa;
        Cursor invisible;
 

-       if (dpy == NULL || screen < 0)
+       if(dpy == NULL || screen < 0)

                return NULL;
 
                return NULL;
 

-       lock = malloc(sizeof(struct st_lock));
-       if (lock == NULL)
+       lock = malloc(sizeof(Lock));
+       if(lock == NULL)

                return NULL;
 
        lock->screen = screen;
                return NULL;
 
        lock->screen = screen;


@@ -175,86 +209,94 @@ lockscreen(Display *dpy, int screen) {
        /* init */
        wa.override_redirect = 1;
        wa.background_pixel = BlackPixel(dpy, lock->screen);
        /* init */
        wa.override_redirect = 1;
        wa.background_pixel = BlackPixel(dpy, lock->screen);

-       lock->w = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
+       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);
                        0, DefaultDepth(dpy, lock->screen), CopyFromParent,
                        DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);

-       XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), "black", &black, &dummy);
-       lock->pmap = XCreateBitmapFromData(dpy, lock->w, curs, 8, 8);
-       invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &black, &black, 0, 0);
-       XDefineCursor(dpy, lock->w, invisible);
-       XMapRaised(dpy, lock->w);
+       XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR2, &color, &dummy);
+       lock->colors[1] = color.pixel;
+       XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR1, &color, &dummy);
+       lock->colors[0] = color.pixel;
+       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);
+       XMapRaised(dpy, lock->win);

        for(len = 1000; len; len--) {
                if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
                        GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
                        break;
                usleep(1000);
        }
        for(len = 1000; len; len--) {
                if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
                        GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
                        break;
                usleep(1000);
        }

-       if((running = running && (len > 0))) {
+       if(running && (len > 0)) {

                for(len = 1000; len; len--) {
                        if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
                                == GrabSuccess)
                                break;
                        usleep(1000);
                }
                for(len = 1000; len; len--) {
                        if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
                                == GrabSuccess)
                                break;
                        usleep(1000);
                }

-               running = (len > 0);

        }
 
        }
 

-       if (!running) {
+       running &= (len > 0);
+       if(!running) {

                unlockscreen(dpy, lock);
                lock = NULL;
        }
                unlockscreen(dpy, lock);
                lock = NULL;
        }

+       else 
+               XSelectInput(dpy, lock->root, SubstructureNotifyMask);

 
        return lock;
 }
 
 static void
 usage(void) {
 
        return lock;
 }
 
 static void
 usage(void) {

-       fprintf(stderr, "usage: %s -v", __progname);
+       fprintf(stderr, "usage: slock [-v]\n");

        exit(EXIT_FAILURE);
 }
 
        exit(EXIT_FAILURE);
 }
 

-static int
-xerrordummy(Display *dpy, XErrorEvent *ee) {
-       return 0;
-}
-

 int
 main(int argc, char **argv) {
 #ifndef HAVE_BSD_AUTH
        const char *pws;
 #endif
        Display *dpy;
 int
 main(int argc, char **argv) {
 #ifndef HAVE_BSD_AUTH
        const char *pws;
 #endif
        Display *dpy;

-       int nscreens, screen;
-
-       struct st_lock **locks;
+       int screen;

 
        if((argc == 2) && !strcmp("-v", argv[1]))
 
        if((argc == 2) && !strcmp("-v", argv[1]))

-               die("slock-%s, © 2006-2012 Anselm R Garbe", VERSION);
+               die("slock-%s, © 2006-2012 Anselm R Garbe\n", VERSION);

        else if(argc != 1)
                usage();
 
        else if(argc != 1)
                usage();
 

+#ifdef __linux__
+       dontkillme();
+#endif
+

        if(!getpwuid(getuid()))
        if(!getpwuid(getuid()))

-               die("no passwd entry for you");
+               die("slock: no passwd entry for you\n");

 
 #ifndef HAVE_BSD_AUTH
        pws = getpw();
 #endif
 
        if(!(dpy = XOpenDisplay(0)))
 
 #ifndef HAVE_BSD_AUTH
        pws = getpw();
 #endif
 
        if(!(dpy = XOpenDisplay(0)))

-               die("cannot open display");
-       /* prevent default error handler to take over */
-       XSetErrorHandler(xerrordummy);
+               die("slock: cannot open display\n");

        /* Get the number of screens in display "dpy" and blank them all. */
        nscreens = ScreenCount(dpy);
        /* Get the number of screens in display "dpy" and blank them all. */
        nscreens = ScreenCount(dpy);

-       locks = malloc(sizeof(struct st_lock *) * nscreens);
-       if (locks == NULL)
-               die("malloc: %s", strerror(errno));
-
-       for (screen = 0; screen < nscreens; screen++)
-               locks[screen] = lockscreen(dpy, screen);
-
+       locks = malloc(sizeof(Lock *) * nscreens);
+       if(locks == NULL)
+               die("slock: malloc: %s\n", strerror(errno));
+       int nlocks = 0;
+       for(screen = 0; screen < nscreens; screen++) {
+               if ( (locks[screen] = lockscreen(dpy, screen)) != NULL)
+                       nlocks++;
+       }

        XSync(dpy, False);
 
        XSync(dpy, False);
 

+       /* Did we actually manage to lock something? */
+       if (nlocks == 0) { // nothing to protect
+               free(locks);
+               XCloseDisplay(dpy);
+               return 1;
+       }
+

        /* Everything is now blank. Now wait for the correct password. */
 #ifdef HAVE_BSD_AUTH
        readpw(dpy);
        /* Everything is now blank. Now wait for the correct password. */
 #ifdef HAVE_BSD_AUTH
        readpw(dpy);


@@ -263,11 +305,10 @@ main(int argc, char **argv) {
 #endif
 
        /* Password ok, unlock everything and quit. */
 #endif
 
        /* Password ok, unlock everything and quit. */

-       for (screen = 0; screen < nscreens; screen++)
+       for(screen = 0; screen < nscreens; screen++)

                unlockscreen(dpy, locks[screen]);
 
        free(locks);
                unlockscreen(dpy, locks[screen]);
 
        free(locks);

-

        XCloseDisplay(dpy);
 
        return 0;
        XCloseDisplay(dpy);
 
        return 0;