Add explicit error message for non-inserted dm-sflc

shufflecake-userland/Makefile.sources

@@ -27,7 +27,7 @@
 #### Main files
 ####
 
-PROJ_SRCS := $(addprefix utils/,crypto.c disk.c dm.c file.c string.c input.c)
+PROJ_SRCS := $(addprefix utils/,crypto.c disk.c dm.c file.c string.c input.c kernmod.c)
 PROJ_SRCS += $(addprefix header/,position_map_legacy.c position_map_lite.c volume_master_block_legacy.c volume_master_block_lite.c device_master_block.c)
 PROJ_SRCS += $(addprefix operations/,volume_header_legacy.c volume_header_lite.c devmapper_legacy.c devmapper_lite.c dmb.c)
 PROJ_SRCS += $(addprefix commands/,init_legacy.c init_lite.c open_legacy.c open_lite.c close.c test_pwd.c change_pwd.c)

shufflecake-userland/include/utils/kernmod.h

@@ -0,0 +1,42 @@
+/*
+ *  Copyright The Shufflecake Project Authors (2022)
+ *  Copyright The Shufflecake Project Contributors (2022)
+ *  Copyright Contributors to the The Shufflecake Project.
+ *  
+ *  See the AUTHORS file at the top-level directory of this distribution and at
+ *  <https://www.shufflecake.net/permalinks/shufflecake-userland/AUTHORS>
+ *  
+ *  This file is part of the program shufflecake-c, which is part of the 
+ *  Shufflecake Project. Shufflecake is a plausible deniability (hidden storage) 
+ *  layer for Linux. See <https://www.shufflecake.net>.
+ *  
+ *  This program is free software: you can redistribute it and/or modify it 
+ *  under the terms of the GNU General Public License as published by the Free 
+ *  Software Foundation, either version 2 of the License, or (at your option) 
+ *  any later version. This program is distributed in the hope that it will be 
+ *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 
+ *  Public License for more details. You should have received a copy of the 
+ *  GNU General Public License along with this program. 
+ *  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef _UTILS_KERNMOD_H_
+#define _UTILS_KERNMOD_H_
+
+
+/*****************************************************
+ *                  INCLUDE SECTION                  *
+ *****************************************************/
+
+#include <stdbool.h>
+
+
+/*****************************************************
+ *           PUBLIC FUNCTIONS PROTOTYPES             *
+ *****************************************************/
+
+bool sflc_isKernelModuleLoaded(char *module_name);
+
+
+#endif /* _UTILS_KERNOMD_H_ */

shufflecake-userland/include/utils/sflc.h

@@ -40,6 +40,8 @@
 
 /* Name of the DM target in the kernel */
 #define SFLC_DM_TARGET_NAME "shufflecake"
+/* Name of the kernel module once inserted */
+#define SFLC_KERNMOD_NAME	"dm_sflc"
 
 /* Modes */
 #define SFLC_MODE_LEGACY	0

shufflecake-userland/src/cli/dispatch.c

@@ -35,6 +35,7 @@
 #include "cli.h"
 #include "utils/sflc.h"
 #include "utils/disk.h"
+#include "utils/kernmod.h"
 #include "utils/log.h"
 
 
@@ -185,7 +186,11 @@ int sflc_cli_dispatch(int argc, char **argv) {
 	    return EINVAL;
     }
     
-    // TODO check that dm_sflc is loaded
+    /* Check that the kernel module is loaded */
+	if (!sflc_isKernelModuleLoaded(SFLC_KERNMOD_NAME)) {
+		printf("Error: kernel module dm-sflc is not inserted.\n");
+		return EINVAL;
+	}
     /* Check that input is actually a block device */
     if (strncmp(args.block_device, "/dev/", 5) != 0 || !sflc_disk_isBlockDevice(args.block_device)) {
         printf("Error: '%s' is not a valid block device.\n", args.block_device);

shufflecake-userland/src/utils/kernmod.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright The Shufflecake Project Authors (2022)
+ * Copyright The Shufflecake Project Contributors (2022)
+ * Copyright Contributors to the The Shufflecake Project.
+ *
+ * See the AUTHORS file at the top-level directory of this distribution and at
+ * <https://www.shufflecake.net/permalinks/shufflecake-userland/AUTHORS>
+ *
+ * This file is part of the program shufflecake-c, which is part of the
+ * Shufflecake Project. Shufflecake is a plausible deniability (hidden storage)
+ * layer for Linux. See <https://www.shufflecake.net>.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 2 of the License, or (at your option)
+ * any later version. This program is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the
+ * GNU General Public License along with this program.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*****************************************************
+ *                 INCLUDE SECTION                  *
+ *****************************************************/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "utils/kernmod.h"
+#include "utils/sflc.h"
+#include "utils/log.h"
+
+
+/*****************************************************
+ *          PUBLIC FUNCTIONS DEFINITIONS            *
+ *****************************************************/
+
+bool sflc_isKernelModuleLoaded(char *module_name) {
+    FILE *fp;
+    char line[SFLC_BIGBUFSIZE];
+
+    // Open /proc/modules to check loaded modules
+    fp = fopen("/proc/modules", "r");
+    if (fp == NULL) {
+        sflc_log_error("Failed to open /proc/modules");
+        return false;
+    }
+
+    // Read each line in /proc/modules
+    while (fgets(line, sizeof(line), fp) != NULL) {
+        // Compare the module name in the current line with the input module name
+        char *current_module = strtok(line, " ");  // First token in the line is the module name
+        if (current_module != NULL && strcmp(current_module, module_name) == 0) {
+            fclose(fp);
+            return true; // Module is loaded
+        }
+    }
+
+    fclose(fp);
+    return false; // Module not found
+}
+