Added the "Allow this time." option.

Now the user can choose the "Allow this time." option when prompted.
`ask_access` will return 2 if this option is selected. So far, only the
GUI for this feature is implemented.

src/ui-socket.c

@@ -28,12 +28,12 @@ int init_ui_socket(const char *filename) {
   }
 }
 
-/*
- * This function is called from the FUSE operations functions. Those are called
- * from separate threads. Therefore, there can be multiple threads that try to
- * ask for access at the same time, but we have to
+/**
+ * @param filename: The file that the process is trying to access
+ * @pram pi: The process information
+ * @return: 0 if access is denied, 1 if access is allowed, 2 if access is allwed
+ * for the runtime of the process
  */
-
 int ask_access(const char *filename, struct process_info pi) {
 
   FILE *fp;
@@ -41,16 +41,31 @@ int ask_access(const char *filename, struct process_info pi) {
       139 + sizeof(pid_t) * 8 + strlen(pi.name) + strlen(filename);
   char *command = (char *)malloc(command_len);
   snprintf(command, command_len,
-           "zenity --question --title \"Allow Access?\" --text \"Allow process "
+           "zenity --question --extra-button \"Allow this time\" --title "
+           "\"Allow Access?\" --text \"Allow process "
            "<tt>%s</tt> with PID <tt>%d</tt> to access <tt>%s</tt>\"",
            pi.name, pi.PID, filename);
+
   // Zenity Question Message Popup
   fp = popen(command, "r");
   free(command);
+
   if (fp == NULL) {
     perror("Pipe returned a error");
     return -1;
-  } else {
-    return WEXITSTATUS(pclose(fp));
   }
+
+  // if the user clicks the "Allow this time" button, `zenity` will only
+  // write it to `stdout`, but the exit code will still be `1`. So, we need
+  // to manually check the output.
+  char buffer[1024];
+  while (fgets(buffer, sizeof(buffer), fp)) {
+    if (strcmp(buffer, "Allow this time.\n") == 0) {
+      pclose(fp);
+      return 2;
+    }
+  }
+
+  int zenity_exit_code = WEXITSTATUS(pclose(fp));
+  return zenity_exit_code;
 }