Implemented the creation of backing disks

src/backing.c

@@ -9,6 +9,8 @@
 #include <unistd.h>
 #include <dirent.h>
 #include <errno.h>
+#include <time.h>
+#include <stdio.h>
 #include <sys/stat.h>
 
 char* get_backings_path(void) {
@@ -182,3 +184,44 @@ char* find_latest_backing(void) {
 
 	return latest_backing;
 }
+
+bool create_backing(const char* disk, const char* description) {
+	// Create the backing disk name
+	uint64_t timestamp = (uint64_t)time(NULL);
+	char* backing_name = NULL;
+
+	if (description == NULL || strlen(description) == 0)
+		backing_name = format("%lu", timestamp);
+	else
+		backing_name = format("%lu-%s", timestamp, description);
+
+	if (backing_name == NULL) {
+		log_msg(LOG_ERROR, "Failed to create the backing disk name.");
+		return false;
+	}
+
+	// Create the backing disk path
+	char* backings_path = get_backings_path();
+	if (backings_path == NULL) {
+		free(backing_name);
+		return false;
+	}
+
+	char* backing_path = format("%s/%s", backings_path, backing_name);
+	free(backing_name);
+	free(backings_path);
+
+	if (backing_path == NULL)
+		return false;
+
+	// Copy the disk to the backing disk
+	if (!copy_file(disk, backing_path, 0755, 0, 0)) {
+		free(backing_path);
+		return false;
+	}
+
+	// Free the backing disk path
+	free(backing_path);
+
+	return true;
+}

src/backing.h

@@ -36,7 +36,7 @@ uint64_t get_backing_creation_time(const char* backing);
 char* find_latest_backing(void);
 
 /// @brief Creates a new backing disk.
-/// @param backing_disk The disk to use as the backing disk. Warning: the disk must be part of the backing disks.
+/// @param disk The disk to use as the backing disk. Warning: the disk must be part of the backing disks.
 /// @param description The description of the backing disk.
 /// @return true if the backing disk was created, otherwise false.
-bool create_backing(const char* backing_disk, const char* description);
+bool create_backing(const char* disk, const char* description);

src/entry.c

@@ -237,3 +237,20 @@ uint64_t get_available_space(void) {
 
 	return statbuf.f_bsize * statbuf.f_bavail;
 }
+
+bool reserve_space(uint64_t space) {
+	// While the available space is not enough, delete the oldest entry
+	while (get_available_space() < space) {
+		char* oldest_entry = find_oldest_entry();
+		if (oldest_entry == NULL)
+			return false;
+
+		bool result = delete_entry(oldest_entry);
+		free(oldest_entry);
+
+		if (!result)
+			return false;
+	}
+
+	return true;
+}

src/sandbox.c

@@ -14,8 +14,18 @@
 #include <errno.h>
 
 int main(int argc, char* argv[]) {
-	while (1) {
-		char* oldest_entry = find_oldest_entry();
-		free(oldest_entry);
+	char** backings = list_backings();
+
+	if (backings == NULL) {
+		fprintf(stderr, "Failed to list the backing disks: %s\n", strerror(errno));
+		return EXIT_FAILURE;
 	}
+
+	for (size_t i = 0; backings[i] != NULL; i++)
+		printf("%s\n", backings[i]);
+
+	for (size_t i = 0; backings[i] != NULL; i++)
+		free(backings[i]);
+
+	free(backings);
 }

src/utils.c

@@ -359,3 +359,49 @@ bool delete_directory(const char* directory, int level) {
 
 	return true;
 }
+
+bool copy_file(const char* source, const char* destination, mode_t mode, uid_t uid, gid_t gid) {
+	// Open the source file
+	FILE* source_file = fopen(source, "r");
+	if (source_file == NULL) {
+		log_msg(LOG_ERROR, "Failed to open file '%s' for reading (%s).", source, strerror(errno));
+		return false;
+	}
+
+	// Open the destination file
+	FILE* destination_file = fopen(destination, "w");
+	if (destination_file == NULL) {
+		log_msg(LOG_ERROR, "Failed to open file '%s' for writing (%s).", destination, strerror(errno));
+		fclose(source_file);
+		return false;
+	}
+
+	// Copy the file
+	char buffer[4096];
+	size_t bytes_read;
+	while ((bytes_read = fread(buffer, 1, sizeof(buffer), source_file)) > 0)
+		if (fwrite(buffer, 1, bytes_read, destination_file) != bytes_read) {
+			log_msg(LOG_ERROR, "Failed to write to file '%s' (%s).", destination, strerror(errno));
+			fclose(source_file);
+			fclose(destination_file);
+			return false;
+		}
+
+	// Close the files
+	fclose(source_file);
+	fclose(destination_file);
+
+	// Change the mode of the destination file
+	if (chmod(destination, mode) != 0) {
+		log_msg(LOG_ERROR, "Failed to change the mode of file '%s' (%s).", destination, strerror(errno));
+		return false;
+	}
+
+	// Change the owner of the destination file
+	if (chown(destination, uid, gid) != 0) {
+		log_msg(LOG_ERROR, "Failed to change the owner of file '%s' (%s).", destination, strerror(errno));
+		return false;
+	}
+
+	return true;
+}

src/utils.h

@@ -47,3 +47,12 @@ bool create_directory(const char* directory, mode_t mode, uid_t uid, gid_t gid);
 /// @param level The current level of recursion. This parameter is used internally and should be set to 0.
 /// @return true if the directory was deleted, otherwise false.
 bool delete_directory(const char* directory, int level);
+
+/// @brief Copies the specified file to the specified destination.
+/// @param source The source file to copy.
+/// @param destination The destination file.
+/// @param mode The mode to use when creating the destination file.
+/// @param uid The user ID to use when creating the destination file.
+/// @param gid The group ID to use when creating the destination file.
+/// @return true if the file was copied, otherwise false.
+bool copy_file(const char* source, const char* destination, mode_t mode, uid_t uid, gid_t gid);