added popup for handling SIGSEGV or SIGFPE

the popup is placed on each of the virtual screens
the user can decide to restart or quit i3
in case of an exit a core-dump is generated

src/util.c

@@ -159,16 +159,16 @@ void check_error(xcb_connection_t *conn, xcb_void_cookie_t cookie, char *err_mes
  *
  */
 char *convert_utf8_to_ucs2(char *input, int *real_strlen) {
-	size_t input_size = strlen(input) + 1;
-	/* UCS-2 consumes exactly two bytes for each glyph */
-	int buffer_size = input_size * 2;
+        size_t input_size = strlen(input) + 1;
+        /* UCS-2 consumes exactly two bytes for each glyph */
+        int buffer_size = input_size * 2;
 
-	char *buffer = smalloc(buffer_size);
-	size_t output_size = buffer_size;
-	/* We need to use an additional pointer, because iconv() modifies it */
-	char *output = buffer;
+        char *buffer = smalloc(buffer_size);
+        size_t output_size = buffer_size;
+        /* We need to use an additional pointer, because iconv() modifies it */
+        char *output = buffer;
 
-	/* We convert the input into UCS-2 big endian */
+        /* We convert the input into UCS-2 big endian */
         if (conversion_descriptor == 0) {
                 conversion_descriptor = iconv_open("UCS-2BE", "UTF-8");
                 if (conversion_descriptor == 0) {
@@ -177,22 +177,22 @@ char *convert_utf8_to_ucs2(char *input, int *real_strlen) {
                 }
         }
 
-	/* Get the conversion descriptor back to original state */
-	iconv(conversion_descriptor, NULL, NULL, NULL, NULL);
+        /* Get the conversion descriptor back to original state */
+        iconv(conversion_descriptor, NULL, NULL, NULL, NULL);
 
-	/* Convert our text */
-	int rc = iconv(conversion_descriptor, (void*)&input, &input_size, &output, &output_size);
+        /* Convert our text */
+        int rc = iconv(conversion_descriptor, (void*)&input, &input_size, &output, &output_size);
         if (rc == (size_t)-1) {
                 perror("Converting to UCS-2 failed");
                 if (real_strlen != NULL)
-		        *real_strlen = 0;
+                        *real_strlen = 0;
                 return NULL;
-	}
+        }
 
         if (real_strlen != NULL)
-	        *real_strlen = ((buffer_size - output_size) / 2) - 1;
+                *real_strlen = ((buffer_size - output_size) / 2) - 1;
 
-	return buffer;
+        return buffer;
 }
 
 /*
@@ -463,6 +463,43 @@ done:
         return matching;
 }
 
+/*
+ * Goes through the list of arguments (for exec()) and checks if the given argument
+ * is present. If not, it copies the arguments (because we cannot realloc it) and
+ * appends the given argument.
+ *
+ */
+static char **append_argument(char **original, char *argument) {
+        int num_args;
+        for (num_args = 0; original[num_args] != NULL; num_args++) {
+                DLOG("original argument: \"%s\"\n", original[num_args]);
+                /* If the argument is already present we return the original pointer */
+                if (strcmp(original[num_args], argument) == 0)
+                        return original;
+        }
+        /* Copy the original array */
+        char **result = smalloc((num_args+2) * sizeof(char*));
+        memcpy(result, original, num_args * sizeof(char*));
+        result[num_args] = argument;
+        result[num_args+1] = NULL;
+
+        return result;
+}
+
+/*
+ * Restart i3 in-place
+ * appends -a to argument list to disable autostart
+ *
+ */
+void i3_restart() {
+        LOG("restarting \"%s\"...\n", start_argv[0]);
+        /* make sure -a is in the argument list or append it */
+        start_argv = append_argument(start_argv, "-a");
+
+        execvp(start_argv[0], start_argv);
+        /* not reached */
+}
+
 #if defined(__OpenBSD__)
 
 /*