Added some small modifications

src/backing.c

@@ -68,3 +68,18 @@ Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path)
 
 	return status;
 }
+
+Status DoesBackingExist(const char* backing_identifier, bool* _result) {
+	// Get the backing path
+	char* backing_path = NULL;
+	Status status = GetBackingDiskPath(backing_identifier, &backing_path);
+	if (status != SUCCESS)
+		return status;
+
+	// Check if the backing exists and is a regular file
+	struct stat st;
+	*_result = stat(backing_path, &st) == 0 && S_ISREG(st.st_mode);
+	free(backing_path);
+
+	return SUCCESS;
+}

src/backing.h

@@ -8,6 +8,8 @@ int GetBackingIndex(const char* backing_identifier);
 Status GetBackingPoolPath(char** _backing_pool_path);
 Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path);
 
+Status DoesBackingExist(const char* backing_identifier, bool* _result);
+
 Status AddBacking(const char* backing_identifier, const char* entry_identifier);
 Status RemoveBacking(const char* backing_identifier);
 

src/entry.c

@@ -1,6 +1,7 @@
 #include "entry.h"
 
 #include "disk.h"
+#include "backing.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -199,6 +200,11 @@ Status ListEntries(char*** _entries) {
 		if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
 			continue;
 
+		bool exists;
+		Status status = DoesEntryExist(entry->d_name, &exists);
+		if (status != SUCCESS || !exists)
+			continue;
+
 		char** new_entries = realloc(*_entries, (count + 2) * sizeof(char*)); // +2 for the new entry and the NULL terminator
 		if (new_entries == NULL) {
 			Log(LOG_LEVEL_ERROR, "Failed to reallocate memory for the entries list (%s).", strerror(errno));
@@ -282,6 +288,40 @@ Status AddRootEntryDisk(const char* entry_identifier, uint64_t disk_size) {
 	return status;
 }
 
+Status AddBackedEntryDisk(const char* entry_identifier, const char* backing_identifier) {
+	// Check if the disk already exists
+	bool exists;
+	Status status = DoesEntryDiskExist(entry_identifier, &exists);
+	if (status != SUCCESS)
+		return status;
+
+	if (exists) {
+		Log(LOG_LEVEL_ERROR, "The disk for the entry '%s' already exists.", entry_identifier);
+		return FAILURE;
+	}
+
+	// Get the backing disk path
+	char* backing_disk_path = NULL;
+	status = GetBackingDiskPath(backing_identifier, &backing_disk_path);
+	if (status != SUCCESS)
+		return status;
+
+	// Get the disk path
+	char* entry_disk_path = NULL;
+	status = GetEntryDiskPath(entry_identifier, &entry_disk_path);
+	if (status != SUCCESS) {
+		free(backing_disk_path);
+		return status;
+	}
+
+	// Create the disk
+	status = CreateBackedDisk(entry_disk_path, backing_disk_path);
+	free(backing_disk_path);
+	free(entry_disk_path);
+
+	return status;
+}
+
 Status RemoveEntryDisk(const char* entry_identifier) {
 	// Check if the disk exists
 	bool exists;

src/entry.h

@@ -20,5 +20,5 @@ Status ClearEntries();
 Status AddRootEntryDisk(const char* entry_identifier, uint64_t disk_size);
 Status AddBackedEntryDisk(const char* entry_identifier, const char* backing_identifier);
 Status RemoveEntryDisk(const char* entry_identifier);
-Status ResetEntryDisk(const char* entry_identifier, const char* backing_identifier);
+Status ResetEntryDisk(const char* entry_identifier, const char* backing_identifier); // TODO
 Status TrimEntryDisk(const char* entry_identifier);

src/sandbox.c

@@ -59,6 +59,7 @@ int main(int argc, char* argv[]) {
 	const char* input = argv[1];
 	size_t input_length = strlen(input);
 
+	// Try and find the best matching command
 	const Command* command = NULL;
 	for (size_t i = 0; i < sizeof(COMMANDS) / sizeof(COMMANDS[0]); i++) {
 		if (COMMANDS[i].name == NULL)
@@ -68,6 +69,7 @@ int main(int argc, char* argv[]) {
 			continue;
 
 		if (strncmp(input, COMMANDS[i].name, input_length) == 0) {
+			// If we have already found a matching command, then the input is ambiguous
 			if (command != NULL) {
 				Log(LOG_LEVEL_ERROR, "Ambiguous command '%s'.", input);
 				return EXIT_FAILURE;
@@ -86,6 +88,7 @@ int main(int argc, char* argv[]) {
 }
 
 int CommandHelp(int argc, char* argv[]) {
+	// If there are no arguments, print the general help message
 	if (argc == 0) {
 		fprintf(stdout, "Usage: sandbox <command> [arguments] [options]\n");
 		fprintf(stdout, "\n");
@@ -105,7 +108,7 @@ int CommandHelp(int argc, char* argv[]) {
 		fprintf(stdout, "\nFor more information, run 'sandbox help <command>'.\n");
 
 		return EXIT_SUCCESS;
-	} else if (argc == 1) {
+	} else if (argc == 1) { // If there is one argument, print the help message for the command
 		const char* input = argv[0];
 
 		for (size_t i = 0; i < sizeof(COMMANDS) / sizeof(COMMANDS[0]); i++) {
@@ -124,7 +127,7 @@ int CommandHelp(int argc, char* argv[]) {
 
 		Log(LOG_LEVEL_ERROR, "Unknown command '%s'.", input);
 		return EXIT_FAILURE;
-	} else {
+	} else { // If there are too many arguments, print an error message
 		Log(LOG_LEVEL_ERROR, "Too many arguments supplied to 'help'.");
 		return EXIT_FAILURE;
 	}