feat(filesystem): Add API call to check whether FS is attached

epicardium/epicardium.h

@@ -78,6 +78,7 @@ typedef _Bool bool;
 #define API_FILE_UNLINK            0x4b
 #define API_FILE_RENAME            0x4c
 #define API_FILE_MKDIR             0x4d
+#define API_FILE_FS_ATTACHED       0x4e
 
 #define API_RTC_GET_SECONDS        0x50
 #define API_RTC_SCHEDULE_ALARM     0x51
@@ -2064,6 +2065,15 @@ API(API_FILE_RENAME, int epic_file_rename(const char *oldp, const char* newp));
  */
 API(API_FILE_MKDIR, int epic_file_mkdir(const char *dirname));
 
+/**
+ * Check whether the filesystem is currently attached and a call like
+ * :c:func:`epic_file_open` has a chance to succeed.
+ *
+ * :return: ``true`` if the filesystem is attached and ``false`` if the
+ *     filesystem is not attached.
+ */
+API(API_FILE_FS_ATTACHED, bool epic_fs_is_attached(void));
+
 /**
  * RTC
  * ===

epicardium/modules/fileops.c

@@ -29,6 +29,17 @@ int epic_file_open(const char *filename, const char *mode)
 	return res;
 }
 
+bool epic_fs_is_attached(void)
+{
+	EpicFileSystem *fs;
+	if (efs_lock_global(&fs) == 0) {
+		efs_unlock_global(fs);
+		return true;
+	} else {
+		return false;
+	}
+}
+
 int epic_file_close(int fd)
 {
 	EpicFileSystem *fs;