src/port/kill.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * kill.c
   4  *        kill()
   5  *
   6  * Copyright (c) 1996-2009, PostgreSQL Global Development Group
   7  *
   8  *      This is a replacement version of kill for Win32 which sends
   9  *      signals that the backend can recognize.
  10  *
  11  * IDENTIFICATION
  12  *        $PostgreSQL$
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16
  17 #include "c.h"
  18
  19 #ifdef WIN32
  20 /* signal sending */
  21 int
  22 pgkill(int pid, int sig)
  23 {
  24         char            pipename[128];
  25         BYTE            sigData = sig;
  26         BYTE            sigRet = 0;
  27         DWORD           bytes;
  28         int                     pipe_tries;
  29
  30         /* we allow signal 0 here, but it will be ignored in pg_queue_signal */
  31         if (sig >= PG_SIGNAL_COUNT || sig < 0)
  32         {
  33                 errno = EINVAL;
  34                 return -1;
  35         }
  36         if (pid <= 0)
  37         {
  38                 /* No support for process groups */
  39                 errno = EINVAL;
  40                 return -1;
  41         }
  42         snprintf(pipename, sizeof(pipename), "\\\\.\\pipe\\pgsignal_%u", pid);
  43
  44         /*
  45          * Writing data to the named pipe can fail for transient reasons.
  46          * Therefore, it is useful to retry if it fails.  The maximum number of
  47          * calls to make was empirically determined from a 90-hour notification
  48          * stress test.
  49          */
  50         for (pipe_tries = 0; pipe_tries < 3; pipe_tries++)
  51         {
  52                 if (CallNamedPipe(pipename, &sigData, 1, &sigRet, 1, &bytes, 1000))
  53                 {
  54                         if (bytes != 1 || sigRet != sig)
  55                         {
  56                                 errno = ESRCH;
  57                                 return -1;
  58                         }
  59                         return 0;
  60                 }
  61         }
  62
  63         if (GetLastError() == ERROR_FILE_NOT_FOUND)
  64                 errno = ESRCH;
  65         else if (GetLastError() == ERROR_ACCESS_DENIED)
  66                 errno = EPERM;
  67         else
  68                 errno = EINVAL;
  69         return -1;
  70 }
  71
  72 #endif