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/*++
/* NAME
/* killme_after 3
/* SUMMARY
/* programmed death
/* SYNOPSIS
/* #include <killme_after.h>
/*
/* void killme_after(seconds)
/* unsigned int seconds;
/* DESCRIPTION
/* The killme_after() function does a best effort to terminate
/* the process after the specified time, should it still exist.
/* It is meant to be used in a signal handler, as an insurance
/* against getting stuck somewhere while preparing for exit.
/* DIAGNOSTICS
/* None. This routine does a best effort, damn the torpedoes.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <signal.h>
#include <unistd.h>
/* Utility library. */
#include <killme_after.h>
/* killme_after - self-assured death */
void killme_after(unsigned int seconds)
{
struct sigaction sig_action;
/*
* Schedule an ALARM signal, and make sure the signal will be delivered
* even if we are being called from a signal handler and SIGALRM delivery
* is blocked.
*
* Undocumented: when a process runs with PID 1, Linux won't deliver a
* signal unless the process specifies a handler (i.e. SIG_DFL is treated
* as SIG_IGN). Conveniently, _exit() can be used directly as a signal
* handler. This changes the wait status that a parent would see, but in
* the case of "init" mode on Linux, no-one would care.
*/
alarm(0);
sigemptyset(&sig_action.sa_mask);
sig_action.sa_flags = 0;
sig_action.sa_handler = (getpid() == 1 ? _exit : SIG_DFL);
sigaction(SIGALRM, &sig_action, (struct sigaction *) 0);
alarm(seconds);
sigaddset(&sig_action.sa_mask, SIGALRM);
sigprocmask(SIG_UNBLOCK, &sig_action.sa_mask, (sigset_t *) 0);
}
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