diplodocus.org Git - nmh/blob - sbr/client.c

   1
   2 /*
   3  * client.c -- connect to a server
   4  *
   5  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   6  * COPYRIGHT file in the root directory of the nmh distribution for
   7  * complete copyright information.
   8  */
   9
  10 #include <h/mh.h>
  11 #include <h/mts.h>
  12 #include <h/utils.h>
  13 #include <sys/socket.h>
  14 #include <netinet/in.h>
  15 #include <netdb.h>
  16 #include <arpa/inet.h>
  17 #include <errno.h>
  18
  19
  20 int
  21 client (char *server, char *service, char *response, int len_response,
  22         int debug)
  23 {
  24     int sd, rc;
  25     struct addrinfo hints, *res, *ai;
  26
  27     if (!server || *server == '\0') {
  28         snprintf(response, len_response, "Internal error: NULL server name "
  29                  "passed to client()");
  30         return NOTOK;
  31     }
  32
  33     memset(&hints, 0, sizeof(hints));
  34 #ifdef AI_ADDRCONFIG
  35     hints.ai_flags = AI_ADDRCONFIG;
  36 #endif
  37     hints.ai_family = PF_UNSPEC;
  38     hints.ai_socktype = SOCK_STREAM;
  39
  40     if (debug) {
  41         fprintf(stderr, "Trying to connect to \"%s\" ...\n", server);
  42     }
  43
  44     rc = getaddrinfo(server, service, &hints, &res);
  45
  46     if (rc) {
  47         snprintf(response, len_response, "Lookup of \"%s\" failed: %s",
  48                  server, gai_strerror(rc));
  49         return NOTOK;
  50     }
  51
  52     for (ai = res; ai != NULL; ai = ai->ai_next) {
  53         if (debug) {
  54             char address[NI_MAXHOST];
  55             char port[NI_MAXSERV];
  56
  57             rc = getnameinfo(ai->ai_addr, ai->ai_addrlen, address,
  58                              sizeof(address), port, sizeof port,
  59                              NI_NUMERICHOST | NI_NUMERICSERV);
  60
  61             fprintf(stderr, "Connecting to %s:%s...\n",
  62                     rc ? "unknown" : address, rc ? "--" : port);
  63         }
  64
  65         sd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  66
  67         if (sd < 0) {
  68             if (debug)
  69                 fprintf(stderr, "socket() failed: %s\n", strerror(errno));
  70             rc = errno;
  71             continue;
  72         }
  73
  74         if (connect(sd, ai->ai_addr, ai->ai_addrlen) == 0) {
  75             freeaddrinfo(res);
  76             return sd;
  77         }
  78
  79         rc = errno;
  80
  81         if (debug) {
  82             fprintf(stderr, "Connection failed: %s\n", strerror(errno));
  83         }
  84
  85         close(sd);
  86     }
  87
  88     /*
  89      * Improve error handling a bit. If we were given multiple IP addresses
  90      * then return the old "no servers available" error, but point the user
  91      * to -snoop (hopefully that's universal).  Otherwise report a specific
  92      * error.
  93      */
  94
  95     if (res->ai_next)
  96         snprintf(response, len_response, "no servers available (use -snoop "
  97                  "for details");
  98     else
  99         snprintf(response, len_response, "Connection to \"%s\" failed: %s",
 100                  server, strerror(errno));
 101
 102     freeaddrinfo(res);
 103
 104     return NOTOK;
 105 }