psignal, pgsignal, gsignal - post signal to a process
void
psignal(struct proc *p, int signum);
void
pgsignal(struct pgrp *pgrp, int signum, int checkctty);
void
gsignal(int pgid, int signum);
These functions post a signal to one or more processes. The
argument
signum common to all three functions should be in the range
[1-NSIG].
The psignal() function posts signal number signum to the
process represented
by the process structure p. With a few exceptions
noted below,
the target process signal disposition is updated and is
marked as
runnable, so further handling of the signal is done in the
context of the
target process after a context switch. Note that psignal()
does not by
itself cause a context switch to happen.
The target process is not marked as runnable in the following cases:
+o The target process is sleeping uninterruptibly.
The signal
will be noticed when the process returns from the
system call
or trap.
+o The target process is currently ignoring the signal.
+o If a stop signal is sent to a sleeping process
that takes the
default action (see sigaction(2)), the process is
stopped without
awakening it.
+o SIGCONT restarts a stopped process (or puts them
back to sleep)
regardless of the signal action (e.g., blocked or
ignored).
If the target process is being traced, psignal() behaves as
if the target
process were taking the default action for signum. This allows the tracing
process to be notified of the signal.
The pgsignal() function posts signal number signum to each
member of the
process group described by pgrp. If checkctty is non-zero,
the signal
will be posted only to processes that have a controlling
terminal. If
pgrp is NULL no action is taken.
The gsignal() function posts signal number signum to each
member of the
process group identified by the group id pgid. If pgid is
zero no action
is taken.
These functions are implemented in the file
sys/kern/kern_sig.c.
sigaction(2), tsleep(9)
OpenBSD 3.6 June 22, 1996
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