external/ibm-public/postfix/dist/src/global/mail_connect.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      mail_connect 3
   6 /* SUMMARY
   7 /*      intra-mail system connection management
   8 /* SYNOPSIS
   9 /*      #include <mail_proto.h>
  10 /*
  11 /*      VSTREAM *mail_connect(class, name, block_mode)
  12 /*      const char *class;
  13 /*      const char *name;
  14 /*      int     block_mode;
  15 /*
  16 /*      VSTREAM *mail_connect_wait(class, name)
  17 /*      const char *class;
  18 /*      const char *name;
  19 /* DESCRIPTION
  20 /*      This module does low-level connection management for intra-mail
  21 /*      communication.  All reads and writes are subject to a time limit
  22 /*      (controlled by the global variable \fIvar_ipc_timeout\fR). This
  23 /*      protects against deadlock conditions that should never happen.
  24 /*
  25 /*      mail_connect() attempts to connect to the UNIX-domain socket of
  26 /*      the named subsystem. The result is a null pointer in case of failure.
  27 /*
  28 /*      mail_connect_wait() is like mail_connect(), but keeps trying until
  29 /*      the connection succeeds. However, mail_connect_wait() terminates
  30 /*      with a fatal error when the service is down. This is to ensure that
  31 /*      processes terminate when the mail system shuts down.
  32 /*
  33 /*      Arguments:
  34 /* .IP class
  35 /*      Name of a class of local transport channel endpoints,
  36 /*      either \fIpublic\fR (accessible by any local user) or
  37 /*      \fIprivate\fR (administrative access only).
  38 /* .IP service
  39 /*      The name of a local transport endpoint within the named class.
  40 /* .IP block_mode
  41 /*      NON_BLOCKING for a non-blocking connection, or BLOCKING.
  42 /* SEE ALSO
  43 /*      timed_ipc(3), enforce IPC timeouts.
  44 /* LICENSE
  45 /* .ad
  46 /* .fi
  47 /*      The Secure Mailer license must be distributed with this software.
  48 /* AUTHOR(S)
  49 /*      Wietse Venema
  50 /*      IBM T.J. Watson Research
  51 /*      P.O. Box 704
  52 /*      Yorktown Heights, NY 10598, USA
  53 /*--*/
  54
  55 /* System library. */
  56
  57 #include <sys_defs.h>
  58 #include <fcntl.h>
  59 #include <unistd.h>
  60 #include <stdlib.h>
  61 #include <stdarg.h>
  62 #include <errno.h>
  63
  64 /* Utility library. */
  65
  66 #include <msg.h>
  67 #include <vstream.h>
  68 #include <connect.h>
  69 #include <mymalloc.h>
  70 #include <iostuff.h>
  71 #include <stringops.h>
  72
  73 /* Global library. */
  74
  75 #include "timed_ipc.h"
  76 #include "mail_proto.h"
  77
  78 /* mail_connect - connect to mail subsystem */
  79
  80 VSTREAM *mail_connect(const char *class, const char *name, int block_mode)
  81 {
  82     char   *path;
  83     VSTREAM *stream;
  84     int     fd;
  85     char   *sock_name;
  86
  87     path = mail_pathname(class, name);
  88     if ((fd = LOCAL_CONNECT(path, block_mode, 0)) < 0) {
  89         if (msg_verbose)
  90             msg_info("connect to subsystem %s: %m", path);
  91         stream = 0;
  92     } else {
  93         if (msg_verbose)
  94             msg_info("connect to subsystem %s", path);
  95         stream = vstream_fdopen(fd, O_RDWR);
  96         timed_ipc_setup(stream);
  97         sock_name = concatenate(path, " socket", (char *) 0);
  98         vstream_control(stream,
  99                         VSTREAM_CTL_PATH, sock_name,
 100                         VSTREAM_CTL_END);
 101         myfree(sock_name);
 102     }
 103     myfree(path);
 104     return (stream);
 105 }
 106
 107 /* mail_connect_wait - connect to mail service until it succeeds */
 108
 109 VSTREAM *mail_connect_wait(const char *class, const char *name)
 110 {
 111     VSTREAM *stream;
 112     int     count = 0;
 113
 114     /*
 115      * XXX Solaris workaround for ECONNREFUSED on a busy socket.
 116      */
 117     while ((stream = mail_connect(class, name, BLOCKING)) == 0) {
 118         if (count++ >= 10) {
 119             msg_fatal("connect #%d to subsystem %s/%s: %m",
 120                       count, class, name);
 121         } else {
 122             msg_warn("connect #%d to subsystem %s/%s: %m",
 123                      count, class, name);
 124         }
 125         sleep(10);                              /* XXX make configurable */
 126     }
 127     return (stream);
 128 }