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 "client.h"
  10 #include "h/mts.h"
  11 #include "h/utils.h"
  12 #include <fcntl.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     ZERO(&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             int flags;
  76
  77             freeaddrinfo(res);
  78
  79             flags = fcntl(sd, F_GETFD, 0);
  80
  81             if (flags != -1)
  82                 fcntl(sd, F_SETFD, flags | FD_CLOEXEC);
  83
  84             return sd;
  85         }
  86
  87         rc = errno;
  88
  89         if (debug) {
  90             fprintf(stderr, "Connection failed: %s\n", strerror(errno));
  91         }
  92
  93         close(sd);
  94     }
  95
  96     /*
  97      * Improve error handling a bit. If we were given multiple IP addresses
  98      * then return the old "no servers available" error, but point the user
  99      * to -snoop (hopefully that's universal).  Otherwise report a specific
 100      * error.
 101      */
 102
 103     if (res->ai_next)
 104         snprintf(response, len_response, "no servers available (use -snoop "
 105                  "for details");
 106     else
 107         snprintf(response, len_response, "Connection to \"%s\" failed: %s",
 108                  server, strerror(errno));
 109
 110     freeaddrinfo(res);
 111
 112     return NOTOK;
 113 }