sysdeps/mach/hurd/kill.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <errno.h>
  20 #include <sys/types.h>
  21 #include <signal.h>
  22 #include <hurd.h>
  23 #include <hurd/port.h>
  24 #include <hurd/signal.h>
  25 #include <hurd/msg.h>
  26
  27 /* Send signal SIG to process number PID.  If PID is zero,
  28    send SIG to all processes in the current process's process group.
  29    If PID is < -1, send SIG to all processes in process group - PID.  */
  30 int
  31 __kill (pid_t pid, int sig)
  32 {
  33   int delivered = 0;            /* Set when we deliver any signal.  */
  34   error_t err;
  35   mach_port_t proc;
  36   struct hurd_userlink ulink;
  37
  38   void kill_pid (pid_t pid) /* Kill one PID.  */
  39     {
  40       /* SIGKILL is not delivered as a normal signal.
  41          Sending SIGKILL to a process means to terminate its task.  */
  42       if (sig == SIGKILL)
  43         /* Fetch the process's task port and terminate the task.  We
  44            loop in case the process execs and changes its task port.
  45            If the old task port dies after we fetch it but before we
  46            send the RPC, we get MACH_SEND_INVALID_DEST; if it dies
  47            after we send the RPC request but before it is serviced, we
  48            get MIG_SERVER_DIED.  */
  49         do
  50           {
  51             task_t refport;
  52             err = __proc_pid2task (proc, pid, &refport);
  53             /* Ignore zombies.  */
  54             if (!err && refport != MACH_PORT_NULL)
  55               {
  56                 err = __task_terminate (refport);
  57                 __mach_port_deallocate (__mach_task_self (), refport);
  58               }
  59           } while (err == MACH_SEND_INVALID_DEST ||
  60                    err == MIG_SERVER_DIED);
  61       else
  62         {
  63           error_t taskerr;
  64           error_t kill_port (mach_port_t msgport, mach_port_t refport)
  65             {
  66               if (msgport != MACH_PORT_NULL)
  67                 /* Send a signal message to his message port.  */
  68                 return __msg_sig_post (msgport, sig, 0, refport);
  69
  70               /* The process has no message port.  Perhaps try direct
  71                  frobnication of the task.  */
  72
  73               if (taskerr)
  74                 /* If we could not get the task port, we can do nothing.  */
  75                 return taskerr;
  76
  77               if (refport == MACH_PORT_NULL)
  78                 /* proc_pid2task returned success with a null task port.
  79                    That means the process is a zombie.  Signals
  80                    to zombies should return success and do nothing.  */
  81                 return 0;
  82
  83               /* For user convenience in the case of a task that has
  84                  not registered any message port with the proc server,
  85                  translate a few signals to direct task operations.  */
  86               switch (sig)
  87                 {
  88                   /* The only signals that really make sense for an
  89                      unregistered task are kill, suspend, and continue.  */
  90                 case SIGSTOP:
  91                 case SIGTSTP:
  92                   return __task_suspend (refport);
  93                 case SIGCONT:
  94                   return __task_resume (refport);
  95                 case SIGTERM:
  96                 case SIGQUIT:
  97                 case SIGINT:
  98                   return __task_terminate (refport);
  99                 default:
 100                   /* We have full permission to send signals, but there is
 101                      no meaningful way to express this signal.  */
 102                   return EPERM;
 103                 }
 104             }
 105           err = HURD_MSGPORT_RPC (__proc_getmsgport (proc, pid, &msgport),
 106                                   (taskerr = __proc_pid2task (proc, pid,
 107                                                               &refport)) ?
 108                                   __proc_getsidport (proc, &refport) : 0, 1,
 109                                   kill_port (msgport, refport));
 110         }
 111       if (! err)
 112         delivered = 1;
 113     }
 114
 115   proc = _hurd_port_get (&_hurd_ports[INIT_PORT_PROC], &ulink);
 116
 117   if (pid <= 0)
 118     {
 119       /* Send SIG to each process in pgrp (- PID).  */
 120       pid_t pidbuf[10], *pids = pidbuf;
 121       mach_msg_type_number_t i, npids = sizeof (pidbuf) / sizeof (pidbuf[0]);
 122
 123       err = __proc_getpgrppids (proc, - pid, &pids, &npids);
 124       if (!err)
 125         {
 126           for (i = 0; i < npids; ++i)
 127             {
 128               kill_pid (pids[i]);
 129               if (err == ESRCH)
 130                 /* The process died already.  Ignore it.  */
 131                 err = 0;
 132             }
 133           if (pids != pidbuf)
 134             __vm_deallocate (__mach_task_self (),
 135                              (vm_address_t) pids, npids * sizeof (pids[0]));
 136         }
 137     }
 138   else
 139     kill_pid (pid);
 140
 141   _hurd_port_free (&_hurd_ports[INIT_PORT_PROC], &ulink, proc);
 142
 143   /* If we delivered no signals, but ERR is clear, this must mean that
 144      every kill_pid call failed with ESRCH, meaning all the processes in
 145      the pgrp died between proc_getpgrppids and kill_pid; in that case we
 146      fail with ESRCH.  */
 147   return delivered ? 0 : __hurd_fail (err ?: ESRCH);
 148 }
 149
 150 weak_alias (__kill, kill)