sbuild::session Class Reference

Session handler. More...

#include <sbuild-session.h>

Collaboration diagram for sbuild::session:

List of all members.

Public Types

enum operation {
  OPERATION_AUTOMATIC, OPERATION_BEGIN, OPERATION_RECOVER, OPERATION_END,
  OPERATION_RUN
}

Session operations. More...

enum error_code {
  CHDIR, CHDIR_FB, CHILD_CORE, CHILD_FAIL,
  CHILD_FORK, CHILD_SIGNAL, CHILD_WAIT, CHROOT,
  CHROOT_ALIAS, CHROOT_LOCK, CHROOT_NOTFOUND, CHROOT_SETUP,
  CHROOT_UNLOCK, COMMAND_ABS, EXEC, GROUP_GET_SUP,
  GROUP_GET_SUPC, GROUP_SET, GROUP_SET_SUP, GROUP_UNKNOWN,
  PAM, ROOT_DROP, SET_SESSION_ID, SHELL,
  SHELL_FB, SIGNAL_CATCH, SIGNAL_SET, USER_SET,
  USER_SWITCH
}

Error codes. More...

typedef std::vector< chroot::ptr > chroot_list

A list of chroots.

typedef custom_error< error_code > error

Exception type.

typedef std::tr1::shared_ptr
< session > ptr

A shared_ptr to a session object.

Public Member Functions

session (std::string const &service, operation operation, chroot_list const &chroots)

The constructor.

virtual ~session ()

The destructor.

auth::ptr const & get_auth () const

Get the authentication state associated with this session.

void set_auth (auth::ptr &auth)

Set the authentication state associated with this session.

chroot_list const & get_chroots () const

Get the chroots to use in this session.

void set_chroots (chroot_list const &chroots)

Set the chroots to use in this session.

operation get_operation () const

Get the operation this session will perform.

void set_operation (operation operation)

Set the operation this session will perform.

std::string const & get_session_id () const

Get the session identifier.

void set_session_id (std::string const &session_id)

Set the session identifier.

std::string const & get_verbosity () const

Get the message verbosity.

void set_verbosity (std::string const &verbosity)

Set the message verbosity.

bool get_preserve_environment () const

Check if the environment should be preserved in the chroot.

void set_preserve_environment (bool preserve_environment)

Set if the environment should be preserved in the chroot.

bool get_force () const

Get the force status of this session.

void set_force (bool force)

Set the force status of this session.

void save_termios ()

Save terminal state.

void restore_termios ()

Restore terminal state.

int get_child_status () const

Get the exit (wait) status of the last child process to run in this session.

virtual sbuild::auth::status get_auth_status () const

Check if authentication is required, taking users, groups, root-users and root-groups membership of all chroots specified into account.

void run ()

Run a session.

Protected Member Functions

void get_chroot_membership (chroot::ptr const &chroot, bool &in_users, bool &in_root_users, bool &in_groups, bool &in_root_groups) const

Get the chroot authentication properties the user is included in.

virtual auth::status get_chroot_auth_status (auth::status status, chroot::ptr const &chroot) const

Check if authentication is required for a single chroot, taking users, groups, root-users and root-groups membership into account.

virtual void run_impl ()

Run a session.

virtual string_list get_login_directories (sbuild::chroot::ptr &session_chroot, environment const &env) const

Get a list of directories to change to when running a login shell.

virtual string_list get_command_directories (sbuild::chroot::ptr &session_chroot, environment const &env) const

Get a list of directories to change to when running a command Multiple directories are used as fallbacks.

virtual std::string get_shell () const

Get the shell to run.

virtual void get_command (chroot::ptr &session_chroot, std::string &file, string_list &command, environment const &env) const

Get the command to run.

virtual void get_login_command (chroot::ptr &session_chroot, std::string &file, string_list &command) const

Get the command to run a login shell.

virtual void get_user_command (chroot::ptr &session_chroot, std::string &file, string_list &command, environment const &env) const

Get the command to run a user command.

Protected Attributes

std::string cwd

Current working directory.

Private Member Functions

void setup_chroot (chroot::ptr &session_chroot, chroot::setup_type setup_type)

Setup a chroot.

void run_chroot (chroot::ptr &session_chroot)

Run command or login shell in the specified chroot.

void run_child (chroot::ptr &session_chroot)

Run a command or login shell as a child process in the specified chroot.

void wait_for_child (pid_t pid, int &child_status)

Wait for a child process to complete, and check its exit status.

void set_sighup_handler ()

Set the SIGHUP handler.

void clear_sighup_handler ()

Restore the state of SIGHUP prior to setting the handler.

void set_sigint_handler ()

Set the SIGINT handler.

void clear_sigint_handler ()

Restore the state of SIGINT prior to setting the handler.

void set_sigterm_handler ()

Set the SIGTERM handler.

void clear_sigterm_handler ()

Restore the state of SIGTERM prior to setting the handler.

void set_signal_handler (int signal, struct sigaction *saved_signal, void(*handler)(int))

Set a signal handler.

void clear_signal_handler (int signal, struct sigaction *saved_signal)

Restore the state of the signal prior to setting the handler.

Private Attributes

auth::ptr authstat

Authentication state.

chroot_list chroots

The chroots to run the session operation in.

int chroot_status

The current chroot status.

bool lock_status

Lock status for locks acquired during chroot setup.

int child_status

The child exit status.

operation session_operation

The session operation to perform.

std::string session_id

The session identifier.

bool force

The session force status.

struct sigaction saved_sighup_signal

Signal saved while sighup handler is set.

struct sigaction saved_sigint_signal

Signal saved while sigint handler is set.

struct sigaction saved_sigterm_signal

Signal saved while sigterm handler is set.

struct termios saved_termios

Saved terminal settings.

bool termios_ok

Are the saved terminal settings valid?

std::string verbosity

Message verbosity.

bool preserve_environment

Preserve environment?

Detailed Description

Session handler.

This class provides the session handling for schroot. It uses auth, which performs all the necessary PAM actions. This allows more sophisticated handling of user authorisation (users, groups, root-users and root-groups membership in the configuration file) and session management (setting up the session, entering the chroot and running the requested command or shell).

Member Enumeration Documentation

enum sbuild::session::operation

Session operations.

Enumerator:

OPERATION_AUTOMATIC	Begin, end and run a session automatically.
OPERATION_BEGIN	Begin a session.
OPERATION_RECOVER	Recover an existing (but inactive) session.
OPERATION_END	End a session.
OPERATION_RUN	Run a command in an existing session.

enum sbuild::session::error_code

Error codes.

Enumerator:

CHDIR	Failed to change to directory.
CHDIR_FB	Falling back to directory.
CHILD_CORE	Child dumped core.
CHILD_FAIL	Child exited abnormally (reason unknown).
CHILD_FORK	Failed to fork child.
CHILD_SIGNAL	Child terminated by signal.
CHILD_WAIT	Wait for child failed.
CHROOT	Failed to change root to directory.
CHROOT_ALIAS	No chroot found matching alias.
CHROOT_LOCK	Failed to lock chroot.
CHROOT_NOTFOUND	Chroot not found.
CHROOT_SETUP	Setup failed.
CHROOT_UNLOCK	Failed to unlock chroot.
COMMAND_ABS	Command must have an absolute path.
EXEC	Failed to execute.
GROUP_GET_SUP	Failed to get supplementary groups.
GROUP_GET_SUPC	Failed to get supplementary group count.
GROUP_SET	Failed to set group.
GROUP_SET_SUP	Failed to set supplementary groups.
GROUP_UNKNOWN	Group not found.
PAM	PAM error.
ROOT_DROP	Failed to drop root permissions.
SET_SESSION_ID	Chroot does not support setting a session ID.
SHELL	Shell not available.
SHELL_FB	Falling back to shell.
SIGNAL_CATCH	Caught signal.
SIGNAL_SET	Failed to set signal handler.
USER_SET	Failed to set user.
USER_SWITCH	User switching is not permitted.

Constructor & Destructor Documentation

session::session	(	std::string const &	service,
		operation	operation,
		chroot_list const &	chroots
	)

The constructor.

Parameters:

	service	the PAM service name.
	operation	the session operation to perform.
	chroots	the chroots to act upon.

References sbuild::getcwd().

Member Function Documentation

auth::ptr const & session::get_auth ( ) const

Get the authentication state associated with this session.

Returns:: a shared_ptr to the authentication state.

References authstat.

void session::set_auth ( auth::ptr & auth )

Set the authentication state associated with this session.

Parameters:

auth

a shared_ptr to the authentication state.

References authstat.

session::chroot_list const & session::get_chroots ( ) const

Get the chroots to use in this session.

Returns:: a list of chroots.

References chroots.

void session::set_chroots ( chroot_list const & chroots )

Set the chroots to use in this session.

Parameters:

chroots

a list of chroots.

session::operation session::get_operation ( ) const

Get the operation this session will perform.

Returns:: the operation.

References session_operation.

void session::set_operation ( operation operation )

Set the operation this session will perform.

Parameters:

operation

the operation.

References session_operation.

std::string const & session::get_session_id ( ) const

Get the session identifier.

The session identifier is a unique string to identify a session.

Returns:: the session id.

References session_id.

Referenced by run_impl().

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void session::set_session_id ( std::string const & session_id )

Set the session identifier.

The session identifier is a unique string to identify a session.

Parameters:

session_id

the session id.

std::string const & session::get_verbosity ( ) const

Get the message verbosity.

Returns:: the message verbosity.

References verbosity.

void session::set_verbosity ( std::string const & verbosity )

Set the message verbosity.

This will override the chroot message verbosity if set.

Parameters:

verbosity

the message verbosity.

bool session::get_preserve_environment ( ) const

Check if the environment should be preserved in the chroot.

Returns:: true to preserve or false to clean.

References preserve_environment.

Referenced by get_login_command(), and run_child().

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void session::set_preserve_environment ( bool preserve_environment )

Set if the environment should be preserved in the chroot.

Parameters:

preserve_environment

true to preserve or false to clean.

bool session::get_force ( ) const

Get the force status of this session.

Returns:: true if operation will be forced, otherwise false.

References force.

void session::set_force ( bool force )

Set the force status of this session.

Parameters:

force

true to force operation, otherwise false.

int session::get_child_status ( ) const

Get the exit (wait) status of the last child process to run in this session.

Returns:: the exit status.

References child_status.

auth::status session::get_auth_status ( ) const [virtual]

Check if authentication is required, taking users, groups, root-users and root-groups membership of all chroots specified into account.

Todo:: Use set difference rather than iteration and is_group_member.

References sbuild::auth::change_auth(), chroots, get_chroot_auth_status(), and sbuild::auth::STATUS_NONE.

Referenced by run().

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void session::run ( )

Run a session.

The user will be asked for authentication if required, and then the run_impl virtual method will be called.

An auth::error will be thrown on failure.

References authstat, get_auth_status(), and run_impl().

void session::run_impl ( ) [protected, virtual]

Run a session.

If a command has been specified, this will be run in each of the specified chroots. If no command has been specified, a login shell will run in the specified chroot.

An error will be thrown on failure.

References authstat, child_status, CHROOT_NOTFOUND, chroots, clear_sighup_handler(), clear_sigint_handler(), clear_sigterm_handler(), sbuild::DEBUG_NOTICE, sbuild::DEBUG_WARNING, get_chroot_membership(), get_session_id(), sbuild::log_debug(), OPERATION_AUTOMATIC, OPERATION_BEGIN, OPERATION_RUN, restore_termios(), run_chroot(), save_termios(), sbuild::chroot::SESSION_CREATE, session_operation, set_sighup_handler(), set_sigint_handler(), set_sigterm_handler(), setup_chroot(), sbuild::chroot::SETUP_RECOVER, sbuild::chroot::SETUP_START, sbuild::chroot::SETUP_STOP, sbuild::unique_identifier(), and verbosity.

Referenced by run().

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string_list session::get_login_directories	(	sbuild::chroot::ptr &	session_chroot,
		environment const &	env
	)			const `[protected, virtual]`

Get a list of directories to change to when running a login shell.

Multiple directories are used as fallbacks.

Parameters:

	session_chroot	the chroot to setup.
	env	the environment to use for HOME

Returns:: a list of directories

References authstat, cwd, and sbuild::environment::get().

Referenced by run_child().

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string_list session::get_command_directories	(	sbuild::chroot::ptr &	session_chroot,
		environment const &	env
	)			const `[protected, virtual]`

Get a list of directories to change to when running a command Multiple directories are used as fallbacks.

Parameters:

	session_chroot	the chroot to setup.
	env	the environment to use for HOME

Returns:: a list of directories

References authstat, and cwd.

Referenced by run_child().

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std::string session::get_shell ( ) const [protected, virtual]

Get the shell to run.

This finds a suitable shell to run in the chroot, falling back to /bin/sh if necessary. Note that it assumes it is inside the chroot when called.

Returns:: the shell.

References authstat, sbuild::log_exception_warning(), SHELL, and SHELL_FB.

Referenced by get_login_command(), and run_child().

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void session::get_command	(	chroot::ptr &	session_chroot,
		std::string &	file,
		string_list &	command,
		environment const &	env
	)			const `[protected, virtual]`

Get the command to run.

Parameters:

	session_chroot	the chroot to setup.
	file	the filename to pass to execve(2).
	command	the argv to pass to execve(2).
	env	the environment to use for PATH

References get_login_command(), and get_user_command().

Referenced by run_child().

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void session::get_login_command	(	chroot::ptr &	session_chroot,
		std::string &	file,
		string_list &	command
	)			const `[protected, virtual]`

Get the command to run a login shell.

Parameters:

	session_chroot	the chroot to setup.
	file	the filename to pass to execve(2).
	command	the argv to pass to execve(2).

References authstat, sbuild::basename(), sbuild::DEBUG_NOTICE, get_preserve_environment(), get_shell(), sbuild::log_debug(), sbuild::log_info(), and sbuild::chroot::VERBOSITY_VERBOSE.

Referenced by get_command().

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void session::get_user_command	(	chroot::ptr &	session_chroot,
		std::string &	file,
		string_list &	command,
		environment const &	env
	)			const `[protected, virtual]`

Get the command to run a user command.

Parameters:

	session_chroot	the chroot to setup.
	file	the filename to pass to execve(2).
	command	the argv to pass to execve(2).
	env	the environment to use for PATH

References authstat, sbuild::DEBUG_NOTICE, sbuild::find_program_in_path(), sbuild::environment::get(), sbuild::log_debug(), sbuild::log_info(), sbuild::string_list_to_string(), and sbuild::chroot::VERBOSITY_VERBOSE.

Referenced by get_command().

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void session::setup_chroot	(	chroot::ptr &	session_chroot,
		chroot::setup_type	setup_type
	)			`[private]`

Setup a chroot.

This runs all of the commands in setup.d or run.d.

The environment variables CHROOT_NAME, CHROOT_DESCRIPTION, CHROOT_LOCATION, AUTH_USER and AUTH_VERBOSITY are set for use in setup scripts. See schroot-setup(5) for a complete list.

An error will be thrown on failure.

Parameters:

	session_chroot	the chroot to setup.
	setup_type	the type of setup to perform.

References sbuild::environment::add(), authstat, CHILD_FORK, CHROOT_LOCK, CHROOT_SETUP, chroot_status, CHROOT_UNLOCK, sbuild::DEBUG_INFO, lock_status, sbuild::log_debug(), sbuild::log_error(), sbuild::log_exception_error(), OPERATION_AUTOMATIC, OPERATION_BEGIN, OPERATION_END, OPERATION_RECOVER, sbuild::run_parts::run(), session_operation, sbuild::run_parts::set_reverse(), sbuild::run_parts::set_verbose(), sbuild::chroot::SETUP_RECOVER, sbuild::chroot::SETUP_START, sbuild::chroot::SETUP_STOP, sbuild::chroot::VERBOSITY_VERBOSE, and wait_for_child().

Referenced by run_impl().

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void session::run_chroot ( chroot::ptr & session_chroot ) [private]

Run command or login shell in the specified chroot.

An error will be thrown on failure.

Parameters:

session_chroot

the chroot to setup.

References CHILD_FORK, child_status, sbuild::log_error(), sbuild::log_exception_error(), run_child(), and wait_for_child().

Referenced by run_impl().

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void session::run_child ( chroot::ptr & session_chroot ) [private]

Run a command or login shell as a child process in the specified chroot.

This method is only ever to be run in a child process, and will never return.

Parameters:

session_chroot

the chroot to setup.

References authstat, CHDIR, CHDIR_FB, CHROOT, cwd, sbuild::DEBUG_INFO, sbuild::DEBUG_NOTICE, EXEC, sbuild::exec(), sbuild::find_program_in_path(), get_command(), get_command_directories(), get_login_directories(), get_preserve_environment(), get_shell(), sbuild::getcwd(), GROUP_SET, GROUP_SET_SUP, sbuild::log_debug(), sbuild::log_exception_warning(), ROOT_DROP, sbuild::string_list_to_string(), and USER_SET.

Referenced by run_chroot().

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void session::wait_for_child	(	pid_t	pid,
		int &	child_status
	)			`[private]`

Wait for a child process to complete, and check its exit status.

An error will be thrown on failure.

Parameters:

	pid	the pid to wait for.
	child_status	the place to store the child exit status.

References CHILD_CORE, CHILD_FAIL, CHILD_SIGNAL, CHILD_WAIT, chroot_status, sbuild::log_exception_error(), and SIGNAL_CATCH.

Referenced by run_chroot(), and setup_chroot().

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void session::set_sighup_handler ( ) [private]

Set the SIGHUP handler.

An error will be thrown on failure.

References saved_sighup_signal, and set_signal_handler().

Referenced by run_impl().

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void session::set_sigint_handler ( ) [private]

Set the SIGINT handler.

An error will be thrown on failure.

References saved_sigint_signal, and set_signal_handler().

Referenced by run_impl().

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void session::set_sigterm_handler ( ) [private]

Set the SIGTERM handler.

An error will be thrown on failure.

References saved_sigterm_signal, and set_signal_handler().

Referenced by run_impl().

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void session::set_signal_handler	(	int	signal,
		struct sigaction *	saved_signal,
		void(*)(int)	handler
	)			`[private]`

Set a signal handler.

An error will be thrown on failure.

Parameters:

	signal	the signal number.
	saved_signal	the location to save the current handler.
	handler	the signal handler to install.

References SIGNAL_SET.

Referenced by set_sighup_handler(), set_sigint_handler(), and set_sigterm_handler().

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void session::clear_signal_handler	(	int	signal,
		struct sigaction *	saved_signal
	)			`[private]`

Restore the state of the signal prior to setting the handler.

Parameters:

	signal	the signal number.
	saved_signal	the location from which to restore the saved handler.

Referenced by clear_sighup_handler(), clear_sigint_handler(), and clear_sigterm_handler().

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The documentation for this class was generated from the following files:

sbuild/sbuild-session.h
sbuild/sbuild-session.cc


Public Types
enum	operation { OPERATION_AUTOMATIC, OPERATION_BEGIN, OPERATION_RECOVER, OPERATION_END, OPERATION_RUN }
	Session operations. More...
enum	error_code { CHDIR, CHDIR_FB, CHILD_CORE, CHILD_FAIL, CHILD_FORK, CHILD_SIGNAL, CHILD_WAIT, CHROOT, CHROOT_ALIAS, CHROOT_LOCK, CHROOT_NOTFOUND, CHROOT_SETUP, CHROOT_UNLOCK, COMMAND_ABS, EXEC, GROUP_GET_SUP, GROUP_GET_SUPC, GROUP_SET, GROUP_SET_SUP, GROUP_UNKNOWN, PAM, ROOT_DROP, SET_SESSION_ID, SHELL, SHELL_FB, SIGNAL_CATCH, SIGNAL_SET, USER_SET, USER_SWITCH }
	Error codes. More...
typedef std::vector< chroot::ptr >	chroot_list
	A list of chroots.
typedef custom_error< error_code >	error
	Exception type.
typedef std::tr1::shared_ptr < session >	ptr
	A shared_ptr to a session object.
Public Member Functions
	session (std::string const &service, operation operation, chroot_list const &chroots)
	The constructor.
virtual	~session ()
	The destructor.
auth::ptr const &	get_auth () const
	Get the authentication state associated with this session.
void	set_auth (auth::ptr &auth)
	Set the authentication state associated with this session.
chroot_list const &	get_chroots () const
	Get the chroots to use in this session.
void	set_chroots (chroot_list const &chroots)
	Set the chroots to use in this session.
operation	get_operation () const
	Get the operation this session will perform.
void	set_operation (operation operation)
	Set the operation this session will perform.
std::string const &	get_session_id () const
	Get the session identifier.
void	set_session_id (std::string const &session_id)
	Set the session identifier.
std::string const &	get_verbosity () const
	Get the message verbosity.
void	set_verbosity (std::string const &verbosity)
	Set the message verbosity.
bool	get_preserve_environment () const
	Check if the environment should be preserved in the chroot.
void	set_preserve_environment (bool preserve_environment)
	Set if the environment should be preserved in the chroot.
bool	get_force () const
	Get the force status of this session.
void	set_force (bool force)
	Set the force status of this session.
void	save_termios ()
	Save terminal state.
void	restore_termios ()
	Restore terminal state.
int	get_child_status () const
	Get the exit (wait) status of the last child process to run in this session.
virtual sbuild::auth::status	get_auth_status () const
	Check if authentication is required, taking users, groups, root-users and root-groups membership of all chroots specified into account.
void	run ()
	Run a session.
Protected Member Functions
void	get_chroot_membership (chroot::ptr const &chroot, bool &in_users, bool &in_root_users, bool &in_groups, bool &in_root_groups) const
	Get the chroot authentication properties the user is included in.
virtual auth::status	get_chroot_auth_status (auth::status status, chroot::ptr const &chroot) const
	Check if authentication is required for a single chroot, taking users, groups, root-users and root-groups membership into account.
virtual void	run_impl ()
	Run a session.
virtual string_list	get_login_directories (sbuild::chroot::ptr &session_chroot, environment const &env) const
	Get a list of directories to change to when running a login shell.
virtual string_list	get_command_directories (sbuild::chroot::ptr &session_chroot, environment const &env) const
	Get a list of directories to change to when running a command Multiple directories are used as fallbacks.
virtual std::string	get_shell () const
	Get the shell to run.
virtual void	get_command (chroot::ptr &session_chroot, std::string &file, string_list &command, environment const &env) const
	Get the command to run.
virtual void	get_login_command (chroot::ptr &session_chroot, std::string &file, string_list &command) const
	Get the command to run a login shell.
virtual void	get_user_command (chroot::ptr &session_chroot, std::string &file, string_list &command, environment const &env) const
	Get the command to run a user command.
Protected Attributes
std::string	cwd
	Current working directory.
Private Member Functions
void	setup_chroot (chroot::ptr &session_chroot, chroot::setup_type setup_type)
	Setup a chroot.
void	run_chroot (chroot::ptr &session_chroot)
	Run command or login shell in the specified chroot.
void	run_child (chroot::ptr &session_chroot)
	Run a command or login shell as a child process in the specified chroot.
void	wait_for_child (pid_t pid, int &child_status)
	Wait for a child process to complete, and check its exit status.
void	set_sighup_handler ()
	Set the SIGHUP handler.
void	clear_sighup_handler ()
	Restore the state of SIGHUP prior to setting the handler.
void	set_sigint_handler ()
	Set the SIGINT handler.
void	clear_sigint_handler ()
	Restore the state of SIGINT prior to setting the handler.
void	set_sigterm_handler ()
	Set the SIGTERM handler.
void	clear_sigterm_handler ()
	Restore the state of SIGTERM prior to setting the handler.
void	set_signal_handler (int signal, struct sigaction saved_signal, void(handler)(int))
	Set a signal handler.
void	clear_signal_handler (int signal, struct sigaction *saved_signal)
	Restore the state of the signal prior to setting the handler.
Private Attributes
auth::ptr	authstat
	Authentication state.
chroot_list	chroots
	The chroots to run the session operation in.
int	chroot_status
	The current chroot status.
bool	lock_status
	Lock status for locks acquired during chroot setup.
int	child_status
	The child exit status.
operation	session_operation
	The session operation to perform.
std::string	session_id
	The session identifier.
bool	force
	The session force status.
struct sigaction	saved_sighup_signal
	Signal saved while sighup handler is set.
struct sigaction	saved_sigint_signal
	Signal saved while sigint handler is set.
struct sigaction	saved_sigterm_signal
	Signal saved while sigterm handler is set.
struct termios	saved_termios
	Saved terminal settings.
bool	termios_ok
	Are the saved terminal settings valid?
std::string	verbosity
	Message verbosity.
bool	preserve_environment
	Preserve environment?