Added space reservation

src/backing.c

@@ -177,12 +177,13 @@ result_t import_backing(char** _backing, const char* disk) {
 
 	if (info.backing_path != NULL) {
 		// Get the backing identifier of the parent
+		errno = 0;
 		char* backing = strdup(basename(info.backing_path));
 		if (backing == NULL) {
 			free_disk_info(&info);
 			remove(temp_path);
 			free(temp_path);
-			return failure("Failed to get the backing identifier of the parent.");
+			return failure("Failed to get the backing identifier of the parent of '%s' (%s).", disk, strerror(errno));
 		}
 
 		// Check that the backing exists
@@ -406,13 +407,14 @@ result_t get_backing_parent(char** _parent, const char* backing) {
 	}
 
 	// Get the backing identifier of the parent
+	errno = 0;
 	char* parent = strdup(basename(info.backing_path));
 
 	// Free the disk info as it is not needed anymore
 	free_disk_info(&info);
 
 	if (parent == NULL)
-		return failure("Failed to get the backing identifier of the parent.");
+		return failure("Failed to get the backing identifier of the parent of '%s' (%s).", backing, strerror(errno));
 
 	*_parent = parent;
 	return success();

src/container.c

@@ -9,6 +9,8 @@
 #include <unistd.h>
 #include <libgen.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <sys/types.h>
 
 result_t check_container_identifier(const char* container) {
 	// Check that the container identifier is not null
@@ -271,14 +273,152 @@ result_t get_container_backing(char** _backing, const char* container) {
 	}
 
 	// Get the backing identifier
+	errno = 0;
 	char* backing = strdup(basename(info.backing_path));
 
 	// Free the disk information as it is no longer needed
 	free_disk_info(&info);
 
 	if (backing == NULL)
-		return failure("Failed to get backing identifier for container '%s'.", container);
+		return failure("Failed to get backing identifier for container '%s' (%s).", container, strerror(errno));
 
 	*_backing = backing;
 	return success();
 }
+
+result_t get_container_info(disk_info_t* _info, const char* container) {
+	// Initialize the output parameters
+	_info->size = 0;
+	_info->allocated = 0;
+	_info->backing_path = NULL;
+
+	// Check that the container exists
+	result_t result = check_container_exists(container);
+	if (result != success())
+		return result;
+
+	// Get the container path
+	char* path;
+	result = get_container_path(&path, container);
+	if (result != success())
+		return result;
+
+	// Get the disk information
+	result = get_disk_info(_info, path);
+
+	free(path);
+
+	return result;
+}
+
+result_t get_oldest_container(char** _container) {
+	// Initialize the output parameters
+	*_container = NULL;
+
+	// List the containers
+	char** containers;
+	result_t result = list_containers(&containers);
+	if (result != success())
+		return result;
+
+	// Find the oldest container
+	char* oldest_container = NULL;
+	time_t oldest_time = 0;
+
+	for (size_t i = 0; containers[i] != NULL; i++) {
+		// Get the container path
+		char* path;
+		result = get_container_path(&path, containers[i]);
+		if (result != success())
+			continue;
+
+		// Get information about the container file
+		struct stat st;
+		errno = 0;
+		if (stat(path, &st) != 0) {
+			free(path);
+			continue;
+		}
+
+		// Check if the container is older than the current oldest
+		if (oldest_container == NULL || st.st_mtime < oldest_time) {
+			oldest_container = containers[i];
+			oldest_time = st.st_mtime;
+		}
+	}
+
+	// Duplicate the oldest container
+	if (oldest_container != NULL) {
+		errno = 0;
+		*_container = strdup(oldest_container);
+		if (*_container == NULL) {
+			for (size_t i = 0; containers[i] != NULL; i++)
+				free(containers[i]);
+			free(containers);
+			return failure("Failed to allocate memory for the oldest container (%s).", strerror(errno));
+		}
+	}
+
+	// Free the containers
+	for (size_t i = 0; containers[i] != NULL; i++)
+		free(containers[i]);
+	free(containers);
+
+	return success();
+}
+
+result_t get_container_pool_space(uint64_t* _space) {
+	// Initialize the output parameters
+	*_space = 0;
+
+	// Get the container pool path
+	char* pool_path;
+	result_t result = get_container_pool_path(&pool_path);
+	if (result != success())
+		return result;
+
+	// Get the space of the container pool
+	struct statvfs st;
+	errno = 0;
+	if (statvfs(pool_path, &st) != 0) {
+		free(pool_path);
+		return failure("Failed to get space of container pool (%s).", strerror(errno));
+	}
+
+	*_space = st.f_bsize * st.f_bavail;
+
+	free(pool_path);
+	return success();
+}
+
+result_t reserve_container_pool_space(uint64_t size) {
+	// As long as there is not enough space in the container pool, remove the oldest container
+	while (true) {
+		// Get the available space in the container pool
+		uint64_t space;
+		result_t result = get_container_pool_space(&space);
+		if (result != success())
+			return result;
+
+		// Check if there is enough space
+		if (space >= size)
+			return success();
+
+		// Get the oldest container
+		char* container;
+		result = get_oldest_container(&container);
+		if (result != success())
+			return result;
+
+		if (container == NULL)
+			return success(); // No more containers to remove
+
+		// Remove the oldest container
+		result = remove_container(container);
+
+		free(container);
+
+		if (result != success())
+			return result;
+	}
+}

src/container.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "utils.h"
+#include "disk.h"
 
 #define CONTAINER_IDENTIFIER_MAX_LENGTH 64
 
@@ -67,3 +68,24 @@ result_t list_containers(char*** _containers);
 /// @param container The container to get the backing of.
 /// @return The result of the operation.
 result_t get_container_backing(char** _backing, const char* container);
+
+/// @brief Gets information about the given container. If the container does not exist, the call will return a failure result with an error message.
+/// @param _info The string pointer to store the resulting disk information in. The caller is responsible for freeing the string.
+/// @param container The container to get information about.
+/// @return The result of the operation.
+result_t get_container_info(disk_info_t* _info, const char* container);
+
+/// @brief Gets the oldest container in the pool.
+/// @param _container The string pointer to store the resulting container in. The caller is responsible for freeing the string.
+/// @return The result of the operation.
+result_t get_oldest_container(char** _container);
+
+/// @brief Gets the available space in the pool.
+/// @param _space The string pointer to store the resulting space in, in bytes. The caller is responsible for freeing the string.
+/// @return The result of the operation.
+result_t get_container_pool_space(uint64_t* _space);
+
+/// @brief Reserves the given space in the pool. If the pool does not have enough space, the oldest containers will be removed to make space.
+/// @param size The size to reserve, in bytes.
+/// @return The result of the operation.
+result_t reserve_container_pool_space(uint64_t size);

src/disk.c

@@ -273,10 +273,11 @@ result_t get_disk_info(disk_info_t* _info, const char* path) {
 		}
 
 		// Duplicate the backing path string
+		errno = 0;
 		backing_path = strdup(backing_str);
 		if (backing_path == NULL) {
 			json_object_put(root);
-			return failure("Failed to allocate memory for the backing path.");
+			return failure("Failed to allocate memory for the backing path (%s).", strerror(errno));
 		}
 	}
 

src/sandbox.c

@@ -67,6 +67,9 @@ int main(int argc, char** argv) {
 	}
 
 	// TODO: Parse commands from the command line
+	char* container;
+	get_oldest_container(&container);
+	printf("Oldest container: %s\n", container);
 }
 
 int command_help(int argc, char* argv[]) {

src/utils.c

@@ -202,6 +202,7 @@ result_t execute(int* _exit_code, char** _stdoutbuf, char** _stderrbuf, const ch
 	va_start(args, executable);
 
 	for (int i = 1; i < argc; i++) {
+		errno = 0;
 		argv[i] = strdup(va_arg(args, const char*));
 		if (argv[i] == NULL) {
 			for (int j = 0; j < i; j++)
@@ -511,13 +512,14 @@ result_t list_files(char*** _files, const char* path, bool (*filter)(const char*
 			continue;
 
 		// Add the entry to the files array
+		errno = 0;
 		files[length] = strdup(entry->d_name);
 		if (files[length] == NULL) {
 			for (size_t i = 0; i < length; i++)
 				free(files[i]);
 			free(files);
 			closedir(dir);
-			return failure("Failed to allocate memory for the file name.");
+			return failure("Failed to allocate memory for the file name (%s).", strerror(errno));
 		}
 
 		length++;