focal (9) SETSETNEQ.9freebsd.gz

NAME

     signal, SIGADDSET, SIGDELSET, SETEMPTYSET, SIGFILLSET, SIGISMEMBER, SIGISEMPTY, SIGNOTEMPTY, SIGSETEQ,
     SIGSETNEQ, SIGSETOR, SIGSETAND, SIGSETNAND, SIGSETCANTMASK, SIG_STOPSIGMASK, SIG_CONTSIGMASK, SIGPENDING,
     cursig, execsigs, issignal, killproc, pgsigio, postsig, sigexit, siginit, signotify, trapsignal — kernel
     signal functions

SYNOPSIS

     #include <sys/param.h>
     #include <sys/proc.h>
     #include <sys/signalvar.h>

     void
     SIGADDSET(sigset_t set, int signo);

     void
     SIGDELSET(sigset_t set, int signo);

     void
     SIGEMPTYSET(sigset_t set);

     void
     SIGFILLSET(sigset_t set);

     int
     SIGISMEMBER(sigset_t set, int signo);

     int
     SIGISEMPTY(sigset_t set);

     int
     SIGNOTEMPTY(sigset_t set);

     int
     SIGSETEQ(sigset_t set1, sigset_t set2);

     int
     SIGSETNEQ(sigset_t set1, sigset_t set2);

     void
     SIGSETOR(sigset_t set1, sigset_t set2);

     void
     SIGSETAND(sigset_t set1, sigset_t set2);

     void
     SIGSETNAND(sigset_t set1, sigset_t set2);

     void
     SIG_CANTMASK(sigset_t set);

     void
     SIG_STOPSIGMASK(sigset_t set);

     void
     SIG_CONTSIGMASK(sigset_t set);

     int
     SIGPENDING(struct proc *p);

     int
     cursig(struct thread *td);

     void
     execsigs(struct proc *p);

     int
     issignal(struct thread *td);

     void
     killproc(struct proc *p, char *why);

     void
     pgsigio(struct sigio **sigiop, int sig, int checkctty);

     void
     postsig(int sig);

     void
     sigexit(struct thread *td, int signum);

     void
     siginit(struct proc *p);

     void
     signotify(struct thread *td);

     void
     trapsignal(struct thread *td, int sig, u_long code);

DESCRIPTION

     The SIGADDSET() macro adds signo to set.  No effort is made to ensure that signo is a valid signal number.

     The SIGDELSET() macro removes signo from set.  No effort is made to ensure that signo is a valid signal
     number.

     The SIGEMPTYSET() macro clears all signals in set.

     The SIGFILLSET() macro sets all signals in set.

     The SIGISMEMBER() macro determines if signo is set in set.

     The SIGISEMPTY() macro determines if set does not have any signals set.

     The SIGNOTEMPTY() macro determines if set has any signals set.

     The SIGSETEQ() macro determines if two signal sets are equal; that is, the same signals are set in both.

     The SIGSETNEQ() macro determines if two signal sets differ; that is, if any signal set in one is not set in
     the other.

     The SIGSETOR() macro ORs the signals set in set2 into set1.

     The SIGSETAND() macro ANDs the signals set in set2 into set1.

     The SIGSETNAND() macro NANDs the signals set in set2 into set1.

     The SIG_CANTMASK() macro clears the SIGKILL and SIGSTOP signals from set.  These two signals cannot be
     blocked or caught and SIG_CANTMASK() is used in code where signals are manipulated to ensure this policy is
     enforced.

     The SIG_STOPSIGMASK() macro clears the SIGSTOP, SIGTSTP, SIGTTIN, and SIGTTOU signals from set.
     SIG_STOPSIGMASK() is used to clear stop signals when a process is waiting for a child to exit or exec, and
     when a process is continuing after having been suspended.

     The SIG_CONTSIGMASK() macro clears the SIGCONT signal from set.  SIG_CONTSIGMASK() is called when a process
     is stopped.

     The SIGPENDING() macro determines if the given process has any pending signals that are not masked.  If the
     process has a pending signal and the process is currently being traced, SIGPENDING() will return true even
     if the signal is masked.

     The cursig() function returns the signal number that should be delivered to process td->td_proc.  If there
     are no signals pending, zero is returned.

     The execsigs() function resets the signal set and signal stack of a process in preparation for an
     execve(2).  The process lock for p must be held before execsigs() is called.

     The issignal() function determines if there are any pending signals for process td->td_proc that should be
     caught, or cause this process to terminate or interrupt its current system call.  If process td->td_proc is
     currently being traced, ignored signals will be handled and the process is always stopped.  Stop signals
     are handled and cleared right away by issignal() unless the process is a member of an orphaned process
     group and the stop signal originated from a TTY.  The process spin lock for td->td_proc may be acquired and
     released.  The sigacts structure td->td_proc->p_sigacts must be locked before calling issignal() and may be
     released and reacquired during the call.  The process lock for td->td_proc must be acquired before calling
     issignal() and may be released and reacquired during the call.  Default signal actions are not taken for
     system processes and init.

     The killproc() function delivers SIGKILL to p.  why is logged as the reason why the process was killed.

     The pgsigio() function sends the signal sig to the process or process group sigiop->sio_pgid.  If checkctty
     is non-zero, the signal is only delivered to processes in the process group that have a controlling
     terminal.  If sigiop->sio_pgid is for a process (> 0), the lock for sigiop->sio_proc is acquired and
     released.  If sigiop->sio_pgid is for a process group (< 0), the process group lock for sigiop->sio_pgrp is
     acquired and released.  The lock sigio_lock is acquired and released.

     The postsig() function handles the actual delivery of the signal sig.  postsig() is called from ast() after
     the kernel has been notified that a signal should be delivered (via a call to signotify(), which causes the
     flag PS_NEEDSIGCHK to be set).  The process lock for process that owns curthread must be held before
     postsig() is called, and the current process cannot be 0.  The lock for the p_sigacts field of the current
     process must be held before postsig() is called, and may be released and reacquired.

     The sigexit() function causes the process that owns td to exit with a return value of signal number sig.
     If required, the process will dump core.  The process lock for the process that owns td must be held before
     sigexit() is called.

     The siginit() function is called during system initialization to cause every signal with a default property
     of SA_IGNORE (except SIGCONT) to be ignored by p.  The process lock for p is acquired and released, as is
     the lock for sigacts structure p->p_sigacts.  The only process that siginit() is ever called for is proc0.

     The signotify() function flags that there are unmasked signals pending that ast() should handle.  The
     process lock for process td->td_proc must be held before signotify() is called, and the thread lock is
     acquired and released.

     The trapsignal() function sends a signal that is the result of a trap to process td->td_proc.  If the
     process is not being traced and the signal can be delivered immediately, trapsignal() will deliver it
     directly; otherwise, trapsignal() will call psignal(9) to cause the signal to be delivered.  The process
     lock for td->td_proc is acquired and released.  The lock for the p_sigacts field of td->td_proc is acquired
     and released.

RETURN VALUES

     The SIGISMEMBER(), SIGISEMPTY(), SIGNOTEMPTY(), SIGSETEQ(), SIGSETNEQ(), and SIGPENDING() macros all return
     non-zero (true) if the condition they are checking is found to be true; otherwise, zero (false) is
     returned.

     The cursig() function returns either a valid signal number or zero.

     issignal() returns either a valid signal number or zero.

SEE ALSO

     gsignal(9), pgsignal(9), psignal(9)

AUTHORS

     This manual page was written by Chad David <davidc@FreeBSD.org>.