Started implementing backing managment

src/backing.c

@@ -0,0 +1,63 @@
+#include "backing.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+bool is_valid_backing_id(const char* backing_id) {
+	if (backing_id == NULL)
+		return false;
+
+	size_t length = strlen(backing_id);
+
+	// Check that the length is valid
+	if (length == 0 || length > MAX_BACKING_LENGTH)
+		return false;
+
+	// Check that the backing id does not contain any slashes
+	for (size_t i = 0; i < length; i++)
+		if (backing_id[i] == '/')
+			return false;
+
+	// Check that the backing id is not a reserved name
+	if (strcmp(backing_id, ".") == 0 || strcmp(backing_id, "..") == 0)
+		return false;
+
+	return true;
+}
+
+Result get_backing_path(const char* backing_id, char** out_path) {
+	*out_path = NULL;
+
+	// Check that the backing id is valid
+	if (!is_valid_backing_id(backing_id)) {
+		log_message(LOG_LEVEL_ERROR, "Invalid backing id '%s'.", backing_id);
+		return FAILURE;
+	}
+
+	return format(out_path, "%s/%s", BACKING_POOL_DIR, backing_id);
+}
+
+Result backing_exists(const char* backing_id, bool* out_exists) {
+	*out_exists = false;
+
+	// Get the path of the backing
+	char* path;
+	Result result = get_entry_path(backing_id, &path);
+	if (result != SUCCESS)
+		return result;
+
+	// Check if the backing exists and is a file
+	struct stat st;
+	bool exists = stat(path, &st) == 0 && S_ISREG(st.st_mode);
+
+	// Free the path
+	free(path);
+
+	// Output the result
+	*out_exists = exists;
+
+	return SUCCESS;
+}

src/backing.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "utils.h"
+#include "disk.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define BACKING_POOL_DIR "/var/lib/sandbox/backings"
+#define MAX_BACKING_LENGTH 256
+
+/// @brief Checks whether the given backing id is valid.
+/// @param backing_id The backing id to check.
+/// @return True if the backing id is valid, false otherwise.
+bool is_valid_backing_id(const char* backing_id);
+
+/// @brief Gets the path of the given backing.
+/// @param backing_id The backing id.
+/// @param out_path The pointer to the output path string. The caller is responsible for freeing the memory.
+/// @return The result of the operation.
+Result get_backing_path(const char* backing_id, char** out_path);
+
+/// @brief Checks whether the given backing exists in the pool.
+/// @param backing_id The backing id.
+/// @param out_exists The pointer to the output boolean.
+/// @return The result of the operation.
+Result backing_exists(const char* backing_id, bool* out_exists);

src/entry.c

@@ -304,6 +304,27 @@ Result list_entries(char*** out_entries) {
 	return SUCCESS;
 }
 
+Result clear_entries(void) {
+	char** entries;
+	Result result = list_entries(&entries);
+	if (result != SUCCESS)
+		return result;
+
+	// Remove each entry
+	for (int i = 0; entries[i] != NULL; i++) {
+		result = remove_entry(entries[i]);
+		if (result != SUCCESS)
+			log_message(LOG_LEVEL_WARNING, "Failed to remove the entry '%s'.", entries[i]);
+	}
+
+	// Free the entries
+	for (int i = 0; entries[i] != NULL; i++)
+		free(entries[i]);
+	free(entries);
+
+	return SUCCESS;
+}
+
 Result reset_entry(const char* entry_id) {
 	// Check that it exists
 	bool exists;

src/entry.h

@@ -9,6 +9,10 @@
 #define ENTRY_POOL_DIR "/var/lib/sandbox/entries"
 #define MAX_ENTRY_LENGTH 256
 
+#define ENTRY_TYPE_ROOT_STRING "ROOT"
+#define ENTRY_TYPE_BACKED_STRING "BACKED"
+#define ENTRY_TYPE_AUTOMATIC_STRING "AUTOMATIC"
+
 typedef enum {
 	ENTRY_TYPE_UNKNOWN,
 	ENTRY_TYPE_ROOT,
@@ -16,10 +20,6 @@ typedef enum {
 	ENTRY_TYPE_AUTOMATIC
 } EntryType;
 
-#define ENTRY_TYPE_ROOT_STRING "ROOT"
-#define ENTRY_TYPE_BACKED_STRING "BACKED"
-#define ENTRY_TYPE_AUTOMATIC_STRING "AUTOMATIC"
-
 typedef struct {
 	EntryType type;
 	char* backing_id;