external/ibm-public/postfix/dist/src/util/stream_trigger.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      stream_trigger 3
   6 /* SUMMARY
   7 /*      wakeup stream server
   8 /* SYNOPSIS
   9 /*      #include <trigger.h>
  10 /*
  11 /*      int     stream_trigger(service, buf, len, timeout)
  12 /*      const char *service;
  13 /*      const char *buf;
  14 /*      ssize_t len;
  15 /*      int     timeout;
  16 /* DESCRIPTION
  17 /*      stream_trigger() wakes up the named stream server by making
  18 /*      a brief connection to it and writing the named buffer.
  19 /*
  20 /*      The connection is closed by a background thread. Some kernels
  21 /*      cannot handle client-side disconnect before the server has
  22 /*      received the message.
  23 /*
  24 /*      Arguments:
  25 /* .IP service
  26 /*      Name of the communication endpoint.
  27 /* .IP buf
  28 /*      Address of data to be written.
  29 /* .IP len
  30 /*      Amount of data to be written.
  31 /* .IP timeout
  32 /*      Deadline in seconds. Specify a value <= 0 to disable
  33 /*      the time limit.
  34 /* DIAGNOSTICS
  35 /*      The result is zero in case of success, -1 in case of problems.
  36 /* SEE ALSO
  37 /*      stream_connect(3), stream client
  38 /* LICENSE
  39 /* .ad
  40 /* .fi
  41 /*      The Secure Mailer license must be distributed with this software.
  42 /* AUTHOR(S)
  43 /*      Wietse Venema
  44 /*      IBM T.J. Watson Research
  45 /*      P.O. Box 704
  46 /*      Yorktown Heights, NY 10598, USA
  47 /*--*/
  48
  49 /* System library. */
  50
  51 #include <sys_defs.h>
  52 #include <unistd.h>
  53 #include <string.h>
  54
  55 /* Utility library. */
  56
  57 #include <msg.h>
  58 #include <connect.h>
  59 #include <iostuff.h>
  60 #include <mymalloc.h>
  61 #include <events.h>
  62 #include <trigger.h>
  63
  64 struct stream_trigger {
  65     int     fd;
  66     char   *service;
  67 };
  68
  69 /* stream_trigger_event - disconnect from peer */
  70
  71 static void stream_trigger_event(int event, char *context)
  72 {
  73     struct stream_trigger *sp = (struct stream_trigger *) context;
  74     static const char *myname = "stream_trigger_event";
  75
  76     /*
  77      * Disconnect.
  78      */
  79     if (event == EVENT_TIME)
  80         msg_warn("%s: read timeout for service %s", myname, sp->service);
  81     event_disable_readwrite(sp->fd);
  82     event_cancel_timer(stream_trigger_event, context);
  83     if (close(sp->fd) < 0)
  84         msg_warn("%s: close %s: %m", myname, sp->service);
  85     myfree(sp->service);
  86     myfree((char *) sp);
  87 }
  88
  89 /* stream_trigger - wakeup stream server */
  90
  91 int     stream_trigger(const char *service, const char *buf, ssize_t len, int timeout)
  92 {
  93     const char *myname = "stream_trigger";
  94     struct stream_trigger *sp;
  95     int     fd;
  96
  97     if (msg_verbose > 1)
  98         msg_info("%s: service %s", myname, service);
  99
 100     /*
 101      * Connect...
 102      */
 103     if ((fd = stream_connect(service, BLOCKING, timeout)) < 0) {
 104         if (msg_verbose)
 105             msg_warn("%s: connect to %s: %m", myname, service);
 106         return (-1);
 107     }
 108     close_on_exec(fd, CLOSE_ON_EXEC);
 109
 110     /*
 111      * Stash away context.
 112      */
 113     sp = (struct stream_trigger *) mymalloc(sizeof(*sp));
 114     sp->fd = fd;
 115     sp->service = mystrdup(service);
 116
 117     /*
 118      * Write the request...
 119      */
 120     if (write_buf(fd, buf, len, timeout) < 0
 121         || write_buf(fd, "", 1, timeout) < 0)
 122         if (msg_verbose)
 123             msg_warn("%s: write to %s: %m", myname, service);
 124
 125     /*
 126      * Wakeup when the peer disconnects, or when we lose patience.
 127      */
 128     if (timeout > 0)
 129         event_request_timer(stream_trigger_event, (char *) sp, timeout + 100);
 130     event_enable_read(fd, stream_trigger_event, (char *) sp);
 131     return (0);
 132 }