Signals definition. More...

Classes
struct	sigset_t
	Structure used to mask and unmask signals. More...

struct	sigaction_t
	Holds the information on how to handle a specific signal. More...

struct	sighand_t
	Describes how each signal must be handled. More...

union	sigval
	Data passed with signal info. More...

struct	siginfo_t
	Stores information about an occurrence of a specific signal. More...

struct	sigqueue_t
	An entry of the signal queue. More...

struct	sigpending_t
	Keeps information of pending signals. More...

Macros
#define	SA_NOCLDSTOP 0x00000001U
	Turn off SIGCHLD when children stop.

#define	SA_NOCLDWAIT 0x00000002U
	Flag on SIGCHLD to inhibit zombies.

#define	SA_SIGINFO 0x00000004U
	sa_sigaction specifies the signal-handling function for signum.

#define	SA_ONSTACK 0x08000000U
	Indicates that a registered stack_t will be used.

#define	SA_RESTART 0x10000000U
	Flag to get restarting signals (which were the default long ago)

#define	SA_NODEFER 0x40000000U
	Prevents the current signal from being masked in the handler.

#define	SA_RESETHAND 0x80000000U
	Clears the handler when the signal is delivered.

#define	SIG_DFL ((sighandler_t)0)
	Default signal handling.

#define	SIG_IGN ((sighandler_t)1)
	ignore signal.

#define	SIG_ERR ((sighandler_t)-1)
	error return from signal.

#define	SEND_SIG_NOINFO ((siginfo_t *)0)
	These can be the second arg to send_sig_info/send_group_sig_info.

Typedefs
typedef void(*	sighandler_t) (int)
	Type of a signal handler.

typedef struct sigset_t	sigset_t
	Structure used to mask and unmask signals. More...

typedef struct sigaction_t	sigaction_t
	Holds the information on how to handle a specific signal.

typedef struct sighand_t	sighand_t
	Describes how each signal must be handled.

typedef union sigval	sigval_t
	Data passed with signal info.

typedef struct siginfo_t	siginfo_t
	Stores information about an occurrence of a specific signal.

typedef struct sigqueue_t	sigqueue_t
	An entry of the signal queue.

typedef struct sigpending_t	sigpending_t
	Keeps information of pending signals.

Enumerations
enum	signal_type_t { SIGHUP = 1 , SIGINT = 2 , SIGQUIT = 3 , SIGILL = 4 , SIGTRAP = 5 , SIGABRT = 6 , SIGEMT = 7 , SIGFPE = 8 , SIGKILL = 9 , SIGBUS = 10 , SIGSEGV = 11 , SIGSYS = 12 , SIGPIPE = 13 , SIGALRM = 14 , SIGTERM = 15 , SIGUSR1 = 16 , SIGUSR2 = 17 , SIGCHLD = 18 , SIGPWR = 19 , SIGWINCH = 20 , SIGURG = 21 , SIGPOLL = 22 , SIGSTOP = 23 , SIGTSTP = 24 , SIGCONT = 25 , SIGTTIN = 26 , SIGTTOU = 27 , SIGVTALRM = 28 , SIGPROF = 29 , SIGXCPU = 30 , SIGXFSZ = 31 , NSIG , SIGHUP = 1 , SIGINT = 2 , SIGQUIT = 3 , SIGILL = 4 , SIGTRAP = 5 , SIGABRT = 6 , SIGEMT = 7 , SIGFPE = 8 , SIGKILL = 9 , SIGBUS = 10 , SIGSEGV = 11 , SIGSYS = 12 , SIGPIPE = 13 , SIGALRM = 14 , SIGTERM = 15 , SIGUSR1 = 16 , SIGUSR2 = 17 , SIGCHLD = 18 , SIGPWR = 19 , SIGWINCH = 20 , SIGURG = 21 , SIGPOLL = 22 , SIGSTOP = 23 , SIGTSTP = 24 , SIGCONT = 25 , SIGTTIN = 26 , SIGTTOU = 27 , SIGVTALRM = 28 , SIGPROF = 29 , SIGXCPU = 30 , SIGXFSZ = 31 , NSIG }
	Signal codes. More...

enum	signal_sender_code_t { SI_NOINFO , SI_USER , SI_KERNEL , SI_QUEUE , SI_TIMER , SI_ASYNCIO , SI_MESGQ , ILL_ILLOPC , ILL_ILLOPN , ILL_ILLADR , ILL_ILLTRP , ILL_PRVOPC , ILL_PRVREG , ILL_COPROC , ILL_BADSTK , FPE_INTDIV , FPE_INTOVF , FPE_FLTDIV , FPE_FLTOVF , FPE_FLTUND , FPE_FLTRES , FPE_FLTINV , FPE_FLTSUB , SEGV_MAPERR , SEGV_ACCERR , BUS_ADRALN , BUS_ADRERR , BUS_OBJERR , TRAP_BRKPT , TRAP_TRACE , CLD_EXITED , CLD_KILLED , CLD_DUMPED , CLD_TRAPPED , CLD_STOPPED , CLD_CONTINUED , POLL_IN , POLL_OUT , POLL_MSG , POLL_ERR , POLL_PRI , POLL_HUP , SI_NOINFO , SI_USER , SI_KERNEL , SI_QUEUE , SI_TIMER , SI_ASYNCIO , SI_MESGQ , ILL_ILLOPC , ILL_ILLOPN , ILL_ILLADR , ILL_ILLTRP , ILL_PRVOPC , ILL_PRVREG , ILL_COPROC , ILL_BADSTK , FPE_INTDIV , FPE_INTOVF , FPE_FLTDIV , FPE_FLTOVF , FPE_FLTUND , FPE_FLTRES , FPE_FLTINV , FPE_FLTSUB , SEGV_MAPERR , SEGV_ACCERR , BUS_ADRALN , BUS_ADRERR , BUS_OBJERR , TRAP_BRKPT , TRAP_TRACE , CLD_EXITED , CLD_KILLED , CLD_DUMPED , CLD_TRAPPED , CLD_STOPPED , CLD_CONTINUED , POLL_IN , POLL_OUT , POLL_MSG , POLL_ERR , POLL_PRI , POLL_HUP }
	Codes that indentify the sender of a signal. More...

enum	sigmask_how_t { SIG_BLOCK , SIG_UNBLOCK , SIG_SETMASK , SIG_BLOCK , SIG_UNBLOCK , SIG_SETMASK }
	Defines what to do with the provided signal mask. More...

Functions
long	sys_sigreturn (struct pt_regs *f)
	Handle the return from a signal handler. More...

int	do_signal (struct pt_regs *f)
	Handles the signals of the current process. More...

int	signals_init (void)
	Initialize the signals. More...

int	sys_kill (pid_t pid, int sig)
	Send signal to one specific process. More...

sighandler_t	sys_signal (int signum, sighandler_t handler, uint32_t sigreturn_addr)
	Sets the disposition of the signal signum to handler. More...

int	sys_sigaction (int signum, const sigaction_t act, sigaction_t oldact, uint32_t sigreturn_addr)
	Examine and change a signal action. More...

int	sys_sigprocmask (int how, const sigset_t set, sigset_t oldset)
	Examine and change blocked signals. More...

int	sys_sigpending (sigset_t *set)
	Provides a snapshot of pending signals. More...

const char *	strsignal (int sig)
	Returns the string describing the given signal. More...

int	sigemptyset (sigset_t *set)
	Prepare an empty set. More...

int	sigfillset (sigset_t *set)
	Prepare a full set. More...

int	sigaddset (sigset_t *set, int signum)
	Adds the given signal to the correct set. More...

int	sigdelset (sigset_t *set, int signum)
	Removes the given signal to the correct set. More...

int	sigismember (sigset_t *set, int signum)
	Checks if the given signal is part of the set. More...

Detailed Description

Signals definition.

Copyright: (c) 2014-2024 This file is distributed under the MIT License. See LICENSE.md for details.

Typedef Documentation

◆ sigset_t

typedef struct sigset_t sigset_t

Structure used to mask and unmask signals.

Each unsigned long consists of 32 bits, thus, the maximum number of signals that may be declared is 64. Signals are divided into two cathegories, identified by the two unsigned longs: [ 1, 31] corresponds to normal signals; [32, 64] corresponds to real-time signals.

Enumeration Type Documentation

◆ sigmask_how_t

enum sigmask_how_t

Defines what to do with the provided signal mask.

Enumerator
SIG_BLOCK	The set of blocked signals is the union of the current set and the set argument.
SIG_UNBLOCK	The signals in set are removed from the current set of blocked signals. It is permissible to attempt to unblock a signal which is not blocked.
SIG_SETMASK	The set of blocked signals is set to the argument set.
SIG_BLOCK	The set of blocked signals is the union of the current set and the set argument.
SIG_UNBLOCK	The signals in set are removed from the current set of blocked signals. It is permissible to attempt to unblock a signal which is not blocked.
SIG_SETMASK	The set of blocked signals is set to the argument set.

◆ signal_sender_code_t

enum signal_sender_code_t

Codes that indentify the sender of a signal.

Enumerator
SI_NOINFO	Unable to determine complete signal information.
SI_USER	Signal sent by kill(), pthread_kill(), raise(), abort() or alarm().
SI_KERNEL	Generic kernel function.
SI_QUEUE	Signal was sent by sigqueue().
SI_TIMER	Signal was generated by expiration of a timer set by timer_settimer().
SI_ASYNCIO	Signal was generated by completion of an asynchronous I/O request.
SI_MESGQ	Signal was generated by arrival of a message on an empty message queue.
ILL_ILLOPC	Illegal opcode.
ILL_ILLOPN	Illegal operand.
ILL_ILLADR	Illegal addressing mode.
ILL_ILLTRP	Illegal trap.
ILL_PRVOPC	Privileged opcode.
ILL_PRVREG	Privileged register.
ILL_COPROC	Coprocessor error.
ILL_BADSTK	Internal stack error.
FPE_INTDIV	Integer divide-by-zero.
FPE_INTOVF	Integer overflow.
FPE_FLTDIV	Floating point divide-by-zero.
FPE_FLTOVF	Floating point overflow.
FPE_FLTUND	Floating point underflow.
FPE_FLTRES	Floating point inexact result.
FPE_FLTINV	Invalid floating point operation.
FPE_FLTSUB	Subscript out of range.
SEGV_MAPERR	Address not mapped.
SEGV_ACCERR	Invalid permissions.
BUS_ADRALN	Invalid address alignment.
BUS_ADRERR	Non-existent physical address.
BUS_OBJERR	Object-specific hardware error.
TRAP_BRKPT	Process breakpoint.
TRAP_TRACE	Process trace trap.
CLD_EXITED	Child has exited.
CLD_KILLED	Child has terminated abnormally and did not create a core file.
CLD_DUMPED	Child has terminated abnormally and created a core file.
CLD_TRAPPED	Traced child has trapped.
CLD_STOPPED	Child has stopped.
CLD_CONTINUED	Stopped child has continued.
POLL_IN	Data input available.
POLL_OUT	Output buffers available.
POLL_MSG	Input message available.
POLL_ERR	I/O error.
POLL_PRI	High priority input available.
POLL_HUP	Device disconnected.
SI_NOINFO	Unable to determine complete signal information.
SI_USER	Signal sent by kill(), pthread_kill(), raise(), abort() or alarm().
SI_KERNEL	Generic kernel function.
SI_QUEUE	Signal was sent by sigqueue().
SI_TIMER	Signal was generated by expiration of a timer set by timer_settimer().
SI_ASYNCIO	Signal was generated by completion of an asynchronous I/O request.
SI_MESGQ	Signal was generated by arrival of a message on an empty message queue.
ILL_ILLOPC	Illegal opcode.
ILL_ILLOPN	Illegal operand.
ILL_ILLADR	Illegal addressing mode.
ILL_ILLTRP	Illegal trap.
ILL_PRVOPC	Privileged opcode.
ILL_PRVREG	Privileged register.
ILL_COPROC	Coprocessor error.
ILL_BADSTK	Internal stack error.
FPE_INTDIV	Integer divide-by-zero.
FPE_INTOVF	Integer overflow.
FPE_FLTDIV	Floating point divide-by-zero.
FPE_FLTOVF	Floating point overflow.
FPE_FLTUND	Floating point underflow.
FPE_FLTRES	Floating point inexact result.
FPE_FLTINV	Invalid floating point operation.
FPE_FLTSUB	Subscript out of range.
SEGV_MAPERR	Address not mapped.
SEGV_ACCERR	Invalid permissions.
BUS_ADRALN	Invalid address alignment.
BUS_ADRERR	Non-existent physical address.
BUS_OBJERR	Object-specific hardware error.
TRAP_BRKPT	Process breakpoint.
TRAP_TRACE	Process trace trap.
CLD_EXITED	Child has exited.
CLD_KILLED	Child has terminated abnormally and did not create a core file.
CLD_DUMPED	Child has terminated abnormally and created a core file.
CLD_TRAPPED	Traced child has trapped.
CLD_STOPPED	Child has stopped.
CLD_CONTINUED	Stopped child has continued.
POLL_IN	Data input available.
POLL_OUT	Output buffers available.
POLL_MSG	Input message available.
POLL_ERR	I/O error.
POLL_PRI	High priority input available.
POLL_HUP	Device disconnected.

◆ signal_type_t

enum signal_type_t

Signal codes.

Enumerator
SIGHUP	Hang up detected on controlling terminal or death of controlling process.
SIGINT	Issued if the user sends an interrupt signal (Ctrl + C).
SIGQUIT	Issued if the user sends a quit signal (Ctrl + D).
SIGILL	Illegal Instruction.
SIGTRAP	Trace/breakpoint trap.
SIGABRT	Abort signal from abort().
SIGEMT	Emulator trap.
SIGFPE	Floating-point arithmetic exception.
SIGKILL	If a process gets this signal it must quit immediately and will not perform any clean-up operations.
SIGBUS	Bus error (bad memory access).
SIGSEGV	Invalid memory reference.
SIGSYS	Bad system call (SVr4).
SIGPIPE	Broken pipe: write to pipe with no readers.
SIGALRM	Alarm clock signal (used for timers).
SIGTERM	Software termination signal (sent by kill by default).
SIGUSR1	User-defined signal 1.
SIGUSR2	User-defined signal 2.
SIGCHLD	Child stopped or terminated.
SIGPWR	Power failure.
SIGWINCH	Window resize signal.
SIGURG	Urgent condition on socket.
SIGPOLL	Pollable event.
SIGSTOP	Stop process.
SIGTSTP	Stop typed at terminal.
SIGCONT	Continue if stopped.
SIGTTIN	Terminal input for background process.
SIGTTOU	Terminal output for background process.
SIGVTALRM	Virtual alarm clock.
SIGPROF	Profiling timer expired.
SIGXCPU	CPU time limit exceeded.
SIGXFSZ	File size limit exceeded.
SIGHUP	Hang up detected on controlling terminal or death of controlling process.
SIGINT	Issued if the user sends an interrupt signal (Ctrl + C).
SIGQUIT	Issued if the user sends a quit signal (Ctrl + D).
SIGILL	Illegal Instruction.
SIGTRAP	Trace/breakpoint trap.
SIGABRT	Abort signal from abort().
SIGEMT	Emulator trap.
SIGFPE	Floating-point arithmetic exception.
SIGKILL	If a process gets this signal it must quit immediately and will not perform any clean-up operations.
SIGBUS	Bus error (bad memory access).
SIGSEGV	Invalid memory reference.
SIGSYS	Bad system call (SVr4).
SIGPIPE	Broken pipe: write to pipe with no readers.
SIGALRM	Alarm clock signal (used for timers).
SIGTERM	Software termination signal (sent by kill by default).
SIGUSR1	User-defined signal 1.
SIGUSR2	User-defined signal 2.
SIGCHLD	Child stopped or terminated.
SIGPWR	Power failure.
SIGWINCH	Window resize signal.
SIGURG	Urgent condition on socket.
SIGPOLL	Pollable event.
SIGSTOP	Stop process.
SIGTSTP	Stop typed at terminal.
SIGCONT	Continue if stopped.
SIGTTIN	Terminal input for background process.
SIGTTOU	Terminal output for background process.
SIGVTALRM	Virtual alarm clock.
SIGPROF	Profiling timer expired.
SIGXCPU	CPU time limit exceeded.
SIGXFSZ	File size limit exceeded.

Function Documentation

◆ do_signal()

int do_signal ( struct pt_regs * f )

Handles the signals of the current process.

Parameters

f	The address of the stack area where the User Mode register contents of the current process are saved.

Returns: If we are handling a signal, thus, regs have been modified to handle it (e.g., eip is now poiting at the handler).

◆ sigaddset()

int sigaddset	(	sigset_t *	set,
		int	signum
	)

Adds the given signal to the correct set.

Parameters

set	The set to manipulate.
signum	The signalt to handle.

Returns: 0 on success and -1 on error.

◆ sigdelset()

int sigdelset	(	sigset_t *	set,
		int	signum
	)

Removes the given signal to the correct set.

Parameters

set	The set to manipulate.
signum	The signalt to handle.

Returns: 0 on success and -1 on error.

◆ sigemptyset()

int sigemptyset ( sigset_t * set )

Prepare an empty set.

Parameters

set	The set to manipulate.

Returns: 0 on success and -1 on error.

◆ sigfillset()

int sigfillset ( sigset_t * set )

Prepare a full set.

Parameters

set	The set to manipulate.

Returns: 0 on success and -1 on error.

◆ sigismember()

int sigismember	(	sigset_t *	set,
		int	signum
	)

Checks if the given signal is part of the set.

Parameters

set	The set to manipulate.
signum	The signalt to handle.

Returns: 1 if signum is a member of set, 0 if signum is not a member, and -1 on error.

◆ signals_init()

int signals_init ( void )

Initialize the signals.

Returns: 1 on success, 0 on failure.

◆ strsignal()

const char* strsignal ( int sig )

Returns the string describing the given signal.

Parameters

sig	The signal to inquire.

Returns: String representing the signal.

◆ sys_kill()

int sys_kill	(	pid_t	pid,
		int	sig
	)

Send signal to one specific process.

Parameters

pid	The PID of the process.
sig	The signal to be sent.

Returns

◆ sys_sigaction()

int sys_sigaction	(	int	signum,
		const sigaction_t *	act,
		sigaction_t *	oldact,
		uint32_t	sigreturn_addr
	)

Examine and change a signal action.

Parameters

signum	Specifies the signal and can be any valid signal except SIGKILL and SIGSTOP.
act	If non-NULL, the new action for signal signum is installed from act.
oldact	If non-NULL, the previous action is saved in oldact.
sigreturn_addr	The address of the sigreturn function.

Returns: returns 0 on success; on error, -1 is returned, and errno is set to indicate the error.

◆ sys_signal()

sighandler_t sys_signal	(	int	signum,
		sighandler_t	handler,
		uint32_t	sigreturn_addr
	)

Sets the disposition of the signal signum to handler.

Parameters

signum	The signal number.
handler	The handler for the signal.
sigreturn_addr	The address of the sigreturn function.

Returns: The previous value of the signal handler, or SIG_ERR on error.

◆ sys_sigpending()

int sys_sigpending ( sigset_t * set )

Provides a snapshot of pending signals.

Parameters

set	where the set of pending signals is returned.

Returns: 0 on success, -1 on failure and errno is set to indicate the error.

◆ sys_sigprocmask()

int sys_sigprocmask	(	int	how,
		const sigset_t *	set,
		sigset_t *	oldset
	)

Examine and change blocked signals.

Parameters

how	Determines the behavior of the call.
set	The set of signals to manage by the function.
oldset	If non-NULL, the previous value of the signal mask is stored here.

Returns: returns 0 on success, and -1 on error (errno is set to indicate the cause).

If set is NULL, then the signal mask is unchanged (i.e., how is ignored), but the current value of the signal mask is nevertheless returned in oldset (if it is not NULL).

◆ sys_sigreturn()

long sys_sigreturn ( struct pt_regs * f )

Handle the return from a signal handler.

Parameters

f	The stack frame when returning from a signal handler.

Returns: never.

Classes

Macros

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ sigset_t

Enumeration Type Documentation

◆ sigmask_how_t

◆ signal_sender_code_t

◆ signal_type_t

Function Documentation

◆ do_signal()

◆ sigaddset()

◆ sigdelset()

◆ sigemptyset()

◆ sigfillset()

◆ sigismember()

◆ signals_init()

◆ strsignal()

◆ sys_kill()

◆ sys_sigaction()

◆ sys_signal()

◆ sys_sigpending()

◆ sys_sigprocmask()

◆ sys_sigreturn()