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/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <errno.h>
#include <sys/types.h>
#include <signal.h>
#include <hurd.h>
#include <hurd/port.h>
#include <hurd/signal.h>
#include <hurd/msg.h>

/* Send signal SIG to process number PID.  If PID is zero,
   send SIG to all processes in the current process's process group.
   If PID is < -1, send SIG to all processes in process group - PID.  */
int
__kill (pid_t pid, int sig)
{
  int delivered = 0;		/* Set when we deliver any signal.  */
  error_t err;
  mach_port_t proc;
  struct hurd_userlink ulink;

  inline void kill_pid (pid_t pid) /* Kill one PID.  */
    {
      /* SIGKILL is not delivered as a normal signal.
	 Sending SIGKILL to a process means to terminate its task.  */
      if (sig == SIGKILL)
	/* Fetch the process's task port and terminate the task.  We
	   loop in case the process execs and changes its task port.
	   If the old task port dies after we fetch it but before we
	   send the RPC, we get MACH_SEND_INVALID_DEST; if it dies
	   after we send the RPC request but before it is serviced, we
	   get MIG_SERVER_DIED.  */
	do
	  {
	    task_t refport;
	    err = __proc_pid2task (proc, pid, &refport);
	    if (!err)
	      {
		err = __task_terminate (refport);
		__mach_port_deallocate (__mach_task_self (), refport);
	      }
	  } while (err == MACH_SEND_INVALID_DEST ||
		   err == MIG_SERVER_DIED);
      else
	err = HURD_MSGPORT_RPC (__proc_getmsgport (proc, pid, &msgport),
				__proc_pid2task (proc, pid, &refport) ?
				__proc_getsidport (proc, &refport) : 0, 1,
				/* If no msgport, we cannot send a signal.  */
				msgport == MACH_PORT_NULL ? EPERM :
				__msg_sig_post (msgport, sig, refport));
      if (! err)
	delivered = 1;
    }

  proc = _hurd_port_get (&_hurd_ports[INIT_PORT_PROC], &ulink);

  if (pid <= 0)
    {
      /* Send SIG to each process in pgrp (- PID).  */
      pid_t pidbuf[10], *pids = pidbuf;
      mach_msg_type_number_t i, npids = sizeof (pidbuf) / sizeof (pidbuf[0]);
      
      err = __proc_getpgrppids (proc, - pid, &pids, &npids);
      if (!err)
	{
	  for (i = 0; i < npids; ++i)
	    {
	      kill_pid (pids[i]);
	      if (err == ESRCH)
		/* The process died already.  Ignore it.  */
		err = 0;
	    }
	  if (pids != pidbuf)
	    __vm_deallocate (__mach_task_self (),
			     (vm_address_t) pids, npids * sizeof (pids[0]));
	}
    }
  else
    kill_pid (pid);

  _hurd_port_free (&_hurd_ports[INIT_PORT_PROC], &ulink, proc);

  /* If we delivered no signals, but ERR is clear, this must mean that
     every kill_pid call failed with ESRCH, meaning all the processes in
     the pgrp died between proc_getpgrppids and kill_pid; in that case we
     fail with ESRCH.  */
  return delivered ? 0 : __hurd_fail (err ?: ESRCH);
}

weak_alias (__kill, kill)