improve error messages and cleanup

1 files changed, 14 insertions, 11 deletions

diff --git a/xkbdlock.c b/xkbdlock.c
index 0cdaedf..d11a8cd 100644
--- a/xkbdlock.c
+++ b/xkbdlock.c
@@ -1,3 +1,4 @@
+#include <errno.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -12,7 +13,7 @@ struct named_mask {
 	unsigned int mask;
 };
 
-static const struct named_mask named_masks[] = {
+static const struct named_mask NAMED_MASKS[] = {
 	{ "Shift", ShiftMask },
 	{ "Control", ControlMask },
 	{ "Ctrl", ControlMask },
@@ -24,12 +25,12 @@ static const struct named_mask named_masks[] = {
 	{ "Mod4", Mod4Mask },
 	{ "Mod5", Mod5Mask }
 };
-#define len_named_masks (sizeof(named_masks) / sizeof(*named_masks))
+#define NUM_NAMED_MASKS (sizeof(NAMED_MASKS) / sizeof(*NAMED_MASKS))
 
-static unsigned int str_to_mask(const char *s)
+static unsigned int name_to_mask(const char *s)
 {
-	for (size_t i = 0; i < len_named_masks; ++i) {
-		const struct named_mask *m = named_masks + i;
+	for (const struct named_mask *m = NAMED_MASKS;
+			m < NAMED_MASKS + NUM_NAMED_MASKS; ++m) {
 		if (!strcmp(s, m->name))
 			return m->mask;
 	}
@@ -46,7 +47,7 @@ static void die(const char *fmt, ...)
 	if (vasprintf(&s, fmt, ap) != -1)
 		fprintf(stderr, "xkbdlock: %s\n", s);
 	else
-		fprintf(stderr, "xkbdlock: unknown error\n");
+		fprintf(stderr, "xkbdlock: %s\n", strerror(errno));
 
 	va_end(ap);
 	exit(1);
@@ -88,15 +89,15 @@ int main(int argc, char **argv)
 	KeySym key = NoSymbol, arg_key;
 
 	for (int i = 1; i < argc; ++i) {
-		if ((arg_mask = str_to_mask(argv[i]))) {
+		if ((arg_mask = name_to_mask(argv[i]))) {
 			mask = mask | arg_mask;
 		} else if (key != NoSymbol) {
 			die("more than one non-modifier key provided");
 		} else {
 			if ((arg_key = XStringToKeysym(argv[i])) == NoSymbol)
-				die("unknown key: %s", argv[i]);
+				die("unknown key '%s'", argv[i]);
 			if (arg_key >= XK_A && arg_key <= XK_Z)
-				die("use Shift modifier for uppercase key: %s",
+				die("use Shift modifier for uppercase key '%s'",
 					argv[i]);
 			key = arg_key;
 		}
@@ -105,16 +106,18 @@ int main(int argc, char **argv)
 	if (key == NoSymbol) {
 		if (mask)
 			die("no non-modifier key provided");
+		fprintf(stderr,
+			"xkbdlock: no release key provided, using Escape\n");
 		key = XK_Escape;
 	}
 
 	Display *d = XOpenDisplay(NULL);
 	if (!d)
-		die("cannot open display");
+		die("cannot open display '%s'", getenv("DISPLAY"));
 
 	for (int i = 0; i < ScreenCount(d); ++i) {
 		if (!grab_kbd(d, i))
-			die("failed to grab keyboard");
+			die("failed to grab keyboard on screen %d", i);
 	}
 
 	wait_for_release(d, key, mask);