fileio.cpp File Reference

Read/write documents and do filesystem interaction. More...

#include <config.h>
#include <cstdio>
#include <cstring>
#include <cstdint>
#include <cstdlib>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <pwd.h>
#include <grp.h>
#include <iostream>
#include <fstream>
#include <stdexcept>
#include <parsnip/parsnip.h>
#include "logging.h"

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Macros
#define	SYSCONFDIR   "/etc"

Functions
static bool	running_as_root (void)
static char *	select_nobody_user (const char *nobody_name, const char *group_names)
static void	drop_root_privs (void)
static void	precreateDirectory (const std::string &directory, bool own)
	Ensure the pianod configuration directory is owned by the user we become when dropping root privileges. More...
static std::string	getConfigDirectory (const char *location, const char *home, const char *package)
	Determine the configuration directory in accordance with the Free Desktop Base Directory Specification. More...
const std::string &	setupConfigDirectory (const char *location, const char *package, const char *nobody_name, const char *nobody_groups_list)
	Choose and configure a directory for configuration files. More...
bool	carefullyWriteFile (std::string filename, Parsnip::Data &document)
	Write a document into a file. More...
const Parsnip::Data	retrieveJsonFile (std::string filename, int minimum_version)
	Restore from a file. More...

Variables
static const char *	FileCreator = "author"
static const char *	FileCreatorVersion = "version"
static std::string	config_directory
static bool	have_nobody = false
static struct passwd	nobody
static gid_t *	nobody_groups
static int	nobody_groups_count

Detailed Description

Read/write documents and do filesystem interaction.

• pianod2

  Author

  Perette Barella

  Date

  2015-02-23

  Copyright

  Copyright (c) 2015-2023 Devious Fish. All rights reserved.

Macro Definition Documentation

SYSCONFDIR

#define SYSCONFDIR   "/etc"

Function Documentation

carefullyWriteFile()

bool carefullyWriteFile	(	std::string	filename,
		Parsnip::Data &	document
	)

Write a document into a file.

Write into a temporary file, and when complete, then rename files so as to keep as backup while moving the new file into place. If compression is supported, writes compressed file; otherwise, writes uncompressed JSON. This is set at compile time, with no run-time choice.

Parameters

filename	The filename, without path.
document	The document to write. Top level must be a document.

Warning

document parameter is altered to contain authoring package identification.

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drop_root_privs()

static void drop_root_privs ( void  )

static

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getConfigDirectory()

static std::string getConfigDirectory ( const char *  location, const char *  home, const char *  package  )

static

Determine the configuration directory in accordance with the Free Desktop Base Directory Specification.

See also

http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html

Parameters

location	Put config files in this directory if specified.
home	Use this directory instead of $HOME if specified.
package	This package's name.

Returns

Directory with package name and a trailing '/' appended.

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precreateDirectory()

static void precreateDirectory ( const std::string &  directory, bool  own  )

static

Ensure the pianod configuration directory is owned by the user we become when dropping root privileges.

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retrieveJsonFile()

const Parsnip::Data retrieveJsonFile	(	std::string	filename,
		int	minimum_version
	)

Restore from a file.

Tries .gz (if supported) first, then falls back to uncompressed version.

Parameters

filename	The filename, without path.
minimum_version	The lowest file format version number supported. If the input file has a version number lower than this, a DataFormatException is thrown.

Returns

A parsed JSON document.

Exceptions

bad_alloc,io_base::failure,or

a Parsnip serialization exception.

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running_as_root()

static bool running_as_root ( void  )

static

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select_nobody_user()

static char* select_nobody_user ( const char *  nobody_name, const char *  group_names  )

static

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setupConfigDirectory()

const std::string& setupConfigDirectory	(	const char *	location,
		const char *	package,
		const char *	nobody_name,
		const char *	nobody_groups_list
	)

Choose and configure a directory for configuration files.

Parameters

location	Pathname to use, or nullptr to use default.
package	Name of this package.
nobody_name	Name of user to run as, if running as root.
nobody_groups_list	List of groups to adopt before giving up root privs.

Returns

Path of the chosen configuration directory, which will exist and be read/write accessible.

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Variable Documentation

config_directory

std::string config_directory

static

FileCreator

const char* FileCreator = "author"

static

FileCreatorVersion

const char* FileCreatorVersion = "version"

static

have_nobody

bool have_nobody = false

static

nobody

struct passwd nobody

static

nobody_groups

gid_t* nobody_groups

static

nobody_groups_count

int nobody_groups_count

static