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

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