Use argv0 instead of passing "slock:" to die every time

slock.c

@@ -46,6 +46,7 @@ static Bool failure = False;
 static Bool rr;
 static int rrevbase;
 static int rrerrbase;
+static char *argv0;
 
 static void
 die(const char *errstr, ...)
@@ -53,6 +54,7 @@ die(const char *errstr, ...)
 	va_list ap;
 
 	va_start(ap, errstr);
+	fprintf(stderr, "%s: ", argv0);
 	vfprintf(stderr, errstr, ap);
 	va_end(ap);
 	exit(1);
@@ -88,9 +90,9 @@ getpw(void)
 	errno = 0;
 	if (!(pw = getpwuid(getuid()))) {
 		if (errno)
-			die("slock: getpwuid: %s\n", strerror(errno));
+			die("getpwuid: %s\n", strerror(errno));
 		else
-			die("slock: cannot retrieve password entry\n");
+			die("cannot retrieve password entry\n");
 	}
 	rval = pw->pw_passwd;
 
@@ -98,7 +100,7 @@ getpw(void)
 	if (rval[0] == 'x' && rval[1] == '\0') {
 		struct spwd *sp;
 		if (!(sp = getspnam(getenv("USER"))))
-			die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
+			die("cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
 		rval = sp->sp_pwdp;
 	}
 #endif
@@ -106,7 +108,7 @@ getpw(void)
 	/* 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");
+		die("cannot drop privileges\n");
 	return rval;
 }
 #endif
@@ -254,7 +256,7 @@ lockscreen(Display *dpy, int screen)
 		usleep(1000);
 	}
 	if (!len) {
-		fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
+		fprintf(stderr, "unable to grab mouse pointer for screen %d\n", screen);
 	} else {
 		for (len = 1000; len; len--) {
 			if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime) == GrabSuccess) {
@@ -264,7 +266,7 @@ lockscreen(Display *dpy, int screen)
 			}
 			usleep(1000);
 		}
-		fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
+		fprintf(stderr, "unable to grab keyboard for screen %d\n", screen);
 	}
 	/* grabbing one of the inputs failed */
 	running = 0;
@@ -281,24 +283,26 @@ main(int argc, char **argv)
 	Display *dpy;
 	int screen;
 
+	argv0 = argv[0], argc--, argv++;
+
 #ifdef __linux__
 	dontkillme();
 #endif
 
 	if (!getpwuid(getuid()))
-		die("slock: no passwd entry for you\n");
+		die("no passwd entry for you\n");
 
 #ifndef HAVE_BSD_AUTH
 	pws = getpw();
 #endif
 
 	if (!(dpy = XOpenDisplay(0)))
-		die("slock: cannot open display\n");
+		die("cannot open display\n");
 	rr = XRRQueryExtension(dpy, &rrevbase, &rrerrbase);
 	/* Get the number of screens in display "dpy" and blank them all. */
 	nscreens = ScreenCount(dpy);
 	if (!(locks = malloc(sizeof(Lock*) * nscreens)))
-		die("slock: malloc: %s\n", strerror(errno));
+		die("Out of memory.\n");
 	int nlocks = 0;
 	for (screen = 0; screen < nscreens; screen++) {
 		if ((locks[screen] = lockscreen(dpy, screen)) != NULL)
@@ -313,11 +317,11 @@ main(int argc, char **argv)
 		return 1;
 	}
 
-	if (argc >= 2 && fork() == 0) {
+	if (argc >= 1 && fork() == 0) {
 		if (dpy)
 			close(ConnectionNumber(dpy));
-		execvp(argv[1], argv+1);
-		die("slock: execvp %s failed: %s\n", argv[1], strerror(errno));
+		execvp(argv[0], argv);
+		die("execvp %s failed: %s\n", argv[0], strerror(errno));
 	}
 
 	/* Everything is now blank. Now wait for the correct password. */