fixed usage string

Calling them unconditionally can result in memory corruption.

.hgtags

@@ -7,3 +7,4 @@ dd226a81c09adfa86db232419b3000b7e406df68 0.6
 c4635bb35a4581261f0187b347d5e596dd390ca3 0.7
 c0eb8221ba49c6d10becc93c063c45196a3bb1ba 0.8
 1e8a77601cb9c872921bbfc47909d9339027b295 0.9
+05b949016e85da011c48783d6896de801d347bed 1.0

LICENSE

@@ -1,6 +1,7 @@
 MIT/X Consortium License
 
-© 2006-2012 Anselm R Garbe <anselm@garbe.us>
+© 2014 Dimitris Papastamos <sin@2f30.org>
+© 2006-2014 Anselm R Garbe <anselm@garbe.us>
 
 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),

Makefile

@@ -18,7 +18,11 @@ options:
 	@echo CC $<
 	@${CC} -c ${CFLAGS} $<
 
-${OBJ}: config.mk
+${OBJ}: config.h config.mk
+
+config.h:
+	@echo creating $@ from config.def.h
+	@cp config.def.h $@
 
 slock: ${OBJ}
 	@echo CC -o $@
@@ -31,7 +35,7 @@ clean:
 dist: clean
 	@echo creating dist tarball
 	@mkdir -p slock-${VERSION}
-	@cp -R LICENSE Makefile README config.mk ${SRC} slock-${VERSION}
+	@cp -R LICENSE Makefile README config.def.h config.mk ${SRC} slock-${VERSION}
 	@tar -cf slock-${VERSION}.tar slock-${VERSION}
 	@gzip slock-${VERSION}.tar
 	@rm -rf slock-${VERSION}

config.def.h

@@ -0,0 +1,2 @@
+#define COLOR1 "black"
+#define COLOR2 "#005577"

config.mk

@@ -1,5 +1,5 @@
 # slock version
-VERSION = 1.0
+VERSION = 1.2
 
 # Customize below to fit your system
 

slock.c

@@ -1,3 +1,4 @@
+
 /* See LICENSE file for license details. */
 #define _XOPEN_SOURCE 500
 #if HAVE_SHADOW_H
@@ -22,10 +23,13 @@
 #include <bsd_auth.h>
 #endif
 
+#include "config.h"
+
 typedef struct {
 	int screen;
 	Window root, win;
 	Pixmap pmap;
+	unsigned long colors[2];
 } Lock;
 
 static Lock **locks;
@@ -42,32 +46,51 @@ die(const char *errstr, ...) {
 	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;
 
+	errno = 0;
 	pw = getpwuid(getuid());
-	if(!pw)
-		die("slock: cannot retrieve password entry (make sure to suid or sgid slock)");
-	endpwent();
+	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");
+	}
 	rval =  pw->pw_passwd;
 
 #if HAVE_SHADOW_H
-	{
+	if (rval[0] == 'x' && rval[1] == '\0') {
 		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 */
-	if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
-		die("slock: 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
@@ -81,11 +104,11 @@ readpw(Display *dpy, const char *pws)
 {
 	char buf[32], passwd[256];
 	int num, screen;
-	unsigned int len;
+	unsigned int len, llen;
 	KeySym ksym;
 	XEvent ev;
 
-	len = 0;
+	len = llen = 0;
 	running = True;
 
 	/* As "slock" stands for "Simple X display locker", the DPMS settings
@@ -112,9 +135,9 @@ readpw(Display *dpy, const char *pws)
 #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
-				if(running != False)
+				if(running)
 					XBell(dpy, 100);
 				len = 0;
 				break;
@@ -126,12 +149,24 @@ readpw(Display *dpy, const char *pws)
 					--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;
 			}
+			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);
@@ -144,6 +179,7 @@ unlockscreen(Display *dpy, Lock *lock) {
 		return;
 
 	XUngrabPointer(dpy, CurrentTime);
+	XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, 2, 0);
 	XFreePixmap(dpy, lock->pmap);
 	XDestroyWindow(dpy, lock->win);
 
@@ -155,7 +191,7 @@ lockscreen(Display *dpy, int screen) {
 	char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
 	unsigned int len;
 	Lock *lock;
-	XColor black, dummy;
+	XColor color, dummy;
 	XSetWindowAttributes wa;
 	Cursor invisible;
 
@@ -176,9 +212,12 @@ lockscreen(Display *dpy, int 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);
-	XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), "black", &black, &dummy);
+	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, &black, &black, 0, 0);
+	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--) {
@@ -194,9 +233,9 @@ lockscreen(Display *dpy, int screen) {
 				break;
 			usleep(1000);
 		}
-		running = (len > 0);
 	}
 
+	running &= (len > 0);
 	if(!running) {
 		unlockscreen(dpy, lock);
 		lock = NULL;
@@ -222,28 +261,42 @@ main(int argc, char **argv) {
 	int screen;
 
 	if((argc == 2) && !strcmp("-v", argv[1]))
-		die("slock-%s, © 2006-2012 Anselm R Garbe\n", VERSION);
+		die("slock-%s, © 2006-2014 slock engineers\n", VERSION);
 	else if(argc != 1)
 		usage();
 
+#ifdef __linux__
+	dontkillme();
+#endif
+
 	if(!getpwuid(getuid()))
-		die("slock: no passwd entry for you");
+		die("slock: no passwd entry for you\n");
 
 #ifndef HAVE_BSD_AUTH
 	pws = getpw();
 #endif
 
 	if(!(dpy = XOpenDisplay(0)))
-		die("slock: cannot open display");
+		die("slock: cannot open display\n");
 	/* Get the number of screens in display "dpy" and blank them all. */
 	nscreens = ScreenCount(dpy);
 	locks = malloc(sizeof(Lock *) * nscreens);
 	if(locks == NULL)
-		die("slock: malloc: %s", strerror(errno));
-	for(screen = 0; screen < nscreens; screen++)
-		locks[screen] = lockscreen(dpy, screen);
+		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);
 
+	/* 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);