release/src/router/apcupsd/src/gapcmon/gethostname.c

   1 #include <netdb.h>
   2 #include <errno.h>
   3 #include <stdlib.h>
   4
   5 #ifdef HAVE_FUNC_GETHOSTBYNAME_R_6
   6 struct hostent * gethostname_re (const char *host,struct hostent *hostbuf,char **tmphstbuf,size_t *hstbuflen)
   7 {
   8         struct hostent *hp;
   9         int herr,res;
  10
  11         if (*hstbuflen == 0)
  12         {
  13                 *hstbuflen = 1024;
  14                 *tmphstbuf = (char *)malloc (*hstbuflen);
  15         }
  16
  17         while (( res =
  18                 gethostbyname_r(host,hostbuf,*tmphstbuf,*hstbuflen,&hp,&herr))
  19                 && (errno == ERANGE))
  20         {
  21                 /* Enlarge the buffer. */
  22                 *hstbuflen *= 2;
  23                 *tmphstbuf = (char *)realloc (*tmphstbuf,*hstbuflen);
  24         }
  25         if (res)
  26                 return NULL;
  27         return hp;
  28 }
  29 #endif
  30 #ifdef HAVE_FUNC_GETHOSTBYNAME_R_5
  31 struct hostent * gethostname_re (const char *host,struct hostent *hostbuf,char **tmphstbuf,size_t *hstbuflen)
  32 {
  33         struct hostent *hp;
  34         int herr;
  35
  36         if (*hstbuflen == 0)
  37         {
  38                 *hstbuflen = 1024;
  39                 *tmphstbuf = (char *)malloc (*hstbuflen);
  40         }
  41
  42         while ((NULL == ( hp =
  43                 gethostbyname_r(host,hostbuf,*tmphstbuf,*hstbuflen,&herr)))
  44                 && (errno == ERANGE))
  45         {
  46                 /* Enlarge the buffer. */
  47                 *hstbuflen *= 2;
  48                 *tmphstbuf = (char *)realloc (*tmphstbuf,*hstbuflen);
  49         }
  50         return hp;
  51 }
  52 #endif
  53 #ifdef HAVE_FUNC_GETHOSTBYNAME_R_3
  54 struct hostent * gethostname_re (const char *host,struct hostent *hostbuf,char **tmphstbuf,size_t *hstbuflen)
  55 {
  56         if (*hstbuflen == 0)
  57         {
  58                 *hstbuflen = sizeof(struct hostent_data);
  59                 *tmphstbuf = (char *)malloc (*hstbuflen);
  60         }
  61         else if (*hstbuflen < sizeof(struct hostent_data))
  62         {
  63                 *hstbuflen = sizeof(struct hostent_data);
  64                 *tmphstbuf = (char *)realloc(*tmphstbuf, *hstbuflen);
  65         }
  66         memset((void *)(*tmphstbuf),0,*hstbuflen);
  67
  68         if (0 != gethostbyname_r(host,hostbuf,(struct hostent_data *)*tmphstbuf))
  69                 return NULL;
  70         return hostbuf;
  71 }
  72 #endif
  73 #ifdef HAVE_FUNC_GETHOSTBYNAME_R_0
  74 #warning WARNING! Your system does not have a thread-safe DNS resolver (gethostbyname_r)!
  75 #warning WARNING! Name service lookups may be corrupted. Consider switching to
  76 #warning WARNING! a more thread-friendly platform.
  77 struct hostent * gethostname_re (const char *host,struct hostent *hostbuf,char **tmphstbuf,size_t *hstbuflen)
  78 {
  79         return gethostbyname(host);
  80 }
  81 #endif