Only output text when in debug mode (fixes problems with xautolock)

i3lock.c

@@ -32,6 +32,7 @@
 #include <cairo/cairo-xcb.h>
 #endif
 
+#include "i3lock.h"
 #include "keysym2ucs.h"
 #include "ucs2_to_utf8.h"
 #include "xcb.h"
@@ -55,7 +56,7 @@ static int numlockmask;
 static int shiftlockmask;
 static int capslockmask;
 static bool beep = false;
-static bool debug_mode = false;
+bool debug_mode = false;
 static bool dpms = false;
 bool unlock_indicator = true;
 static bool dont_fork = false;
@@ -64,11 +65,6 @@ static struct ev_timer *clear_pam_wrong_timeout;
 extern unlock_state_t unlock_state;
 extern pam_state_t pam_state;
 
-#define DEBUG(fmt, ...) do { \
-    if (debug_mode) \
-        printf("[i3lock-debug] " fmt, ##__VA_ARGS__); \
-} while (0)
-
 #ifndef NOLIBCAIRO
 cairo_surface_t *img = NULL;
 bool tile = false;
@@ -123,12 +119,13 @@ static void input_done() {
     redraw_screen();
 
     if (pam_authenticate(pam_handle, 0) == PAM_SUCCESS) {
-        printf("successfully authenticated\n");
+        DEBUG("successfully authenticated\n");
         clear_password_memory();
         exit(0);
     }
 
-    fprintf(stderr, "Authentication failure\n");
+    if (debug_mode)
+        fprintf(stderr, "Authentication failure\n");
 
     pam_state = STATE_PAM_WRONG;
     redraw_screen();
@@ -349,7 +346,8 @@ static void handle_key_press(xcb_key_press_event_t *event) {
     /* convert the keysym to UCS */
     uint16_t ucs = keysym2ucs(sym);
     if ((int16_t)ucs == -1) {
-        fprintf(stderr, "Keysym could not be converted to UCS, skipping\n");
+        if (debug_mode)
+            fprintf(stderr, "Keysym could not be converted to UCS, skipping\n");
         return;
     }
 
@@ -495,8 +493,9 @@ static void xcb_check_cb(EV_P_ ev_check *w, int revents) {
     while ((event = xcb_poll_for_event(conn)) != NULL) {
         if (event->response_type == 0) {
             xcb_generic_error_t *error = (xcb_generic_error_t*)event;
-            fprintf(stderr, "X11 Error received! sequence 0x%x, error_code = %d\n",
-                    error->sequence, error->error_code);
+            if (debug_mode)
+                fprintf(stderr, "X11 Error received! sequence 0x%x, error_code = %d\n",
+                        error->sequence, error->error_code);
             free(event);
             continue;
         }
@@ -671,7 +670,8 @@ int main(int argc, char *argv[]) {
         xcb_dpms_capable_reply_t *dpmsr;
         if ((dpmsr = xcb_dpms_capable_reply(conn, dpmsc, NULL))) {
             if (!dpmsr->capable) {
-                fprintf(stderr, "Disabling DPMS, X server not DPMS capable\n");
+                if (debug_mode)
+                    fprintf(stderr, "Disabling DPMS, X server not DPMS capable\n");
                 dpms = false;
             }
             free(dpmsr);

i3lock.h

@@ -0,0 +1,13 @@
+#ifndef _I3LOCK_H
+#define _I3LOCK_H
+
+/* This macro will only print debug output when started with --debug.
+ * This is important because xautolock (for example) closes stdout/stderr by
+ * default, so just printing something to stdout will lead to the data ending
+ * up on the X11 socket (!). */
+#define DEBUG(fmt, ...) do { \
+    if (debug_mode) \
+        printf("[i3lock-debug] " fmt, ##__VA_ARGS__); \
+} while (0)
+
+#endif

xinerama.c

@@ -13,6 +13,7 @@
 #include <xcb/xcb.h>
 #include <xcb/xinerama.h>
 
+#include "i3lock.h"
 #include "xcb.h"
 #include "xinerama.h"
 
@@ -23,10 +24,11 @@ int xr_screens = 0;
 Rect *xr_resolutions;
 
 static bool xinerama_active;
+extern bool debug_mode;
 
 void xinerama_init() {
     if (!xcb_get_extension_data(conn, &xcb_xinerama_id)->present) {
-        printf("Xinerama extension not found, disabling.\n");
+        DEBUG("Xinerama extension not found, disabling.\n");
         return;
     }
 
@@ -57,7 +59,8 @@ void xinerama_query_screens() {
     cookie = xcb_xinerama_query_screens_unchecked(conn);
     reply = xcb_xinerama_query_screens_reply(conn, cookie, NULL);
     if (!reply) {
-        fprintf(stderr, "Couldn't get Xinerama screens\n");
+        if (debug_mode)
+            fprintf(stderr, "Couldn't get Xinerama screens\n");
         return;
     }
     screen_info = xcb_xinerama_query_screens_screen_info(reply);
@@ -77,7 +80,7 @@ void xinerama_query_screens() {
         xr_resolutions[screen].y = screen_info[screen].y_org;
         xr_resolutions[screen].width = screen_info[screen].width;
         xr_resolutions[screen].height = screen_info[screen].height;
-        printf("found Xinerama screen: %d x %d at %d x %d\n",
+        DEBUG("found Xinerama screen: %d x %d at %d x %d\n",
                         screen_info[screen].width, screen_info[screen].height,
                         screen_info[screen].x_org, screen_info[screen].y_org);
     }