src/kits/network/gethostbyname.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1998-1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18
  19 #include <errno.h>
  20 #include <netdb.h>
  21 #include <stdint.h>
  22 #include <string.h>
  23
  24
  25 #define ALIGN(p) (((uintptr_t)(p) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
  26
  27
  28 struct hostent *gethostbyname_r(const char *, struct hostent *,
  29                                        char *, int, int *);
  30
  31 struct hostent *
  32 gethostbyaddr_r(const char *addr, int len, int type,
  33         struct hostent *hptr, char *buf, int buflen, int *h_errnop);
  34
  35
  36 static struct hostent *
  37 copy_hostent(struct hostent *he, struct hostent *hptr, char *buf, int buflen) {
  38         char *cp;
  39         char **ptr;
  40         int i, n;
  41         int nptr, len;
  42
  43         /* Find out the amount of space required to store the answer. */
  44         nptr = 2; /*%< NULL ptrs */
  45         len = (char *)ALIGN(buf) - buf;
  46         for (i = 0; he->h_addr_list[i]; i++, nptr++) {
  47                 len += he->h_length;
  48         }
  49         for (i = 0; he->h_aliases[i]; i++, nptr++) {
  50                 len += strlen(he->h_aliases[i]) + 1;
  51         }
  52         len += strlen(he->h_name) + 1;
  53         len += nptr * sizeof(char*);
  54
  55         if (len > buflen) {
  56                 errno = ERANGE;
  57                 return 0;
  58         }
  59
  60         /* copy address size and type */
  61         hptr->h_addrtype = he->h_addrtype;
  62         n = hptr->h_length = he->h_length;
  63
  64         ptr = (char **)ALIGN(buf);
  65         cp = (char *)ALIGN(buf) + nptr * sizeof(char *);
  66
  67         /* copy address list */
  68         hptr->h_addr_list = ptr;
  69         for (i = 0; he->h_addr_list[i]; i++ , ptr++) {
  70                 memcpy(cp, he->h_addr_list[i], n);
  71                 hptr->h_addr_list[i] = cp;
  72                 cp += n;
  73         }
  74         hptr->h_addr_list[i] = NULL;
  75         ptr++;
  76
  77         /* copy official name */
  78         n = strlen(he->h_name) + 1;
  79         strcpy(cp, he->h_name);
  80         hptr->h_name = cp;
  81         cp += n;
  82
  83         /* copy aliases */
  84         hptr->h_aliases = ptr;
  85         for (i = 0 ; he->h_aliases[i]; i++) {
  86                 n = strlen(he->h_aliases[i]) + 1;
  87                 strcpy(cp, he->h_aliases[i]);
  88                 hptr->h_aliases[i] = cp;
  89                 cp += n;
  90         }
  91         hptr->h_aliases[i] = NULL;
  92
  93         return hptr;
  94 }
  95
  96
  97 struct hostent *
  98 gethostbyname_r(const char *name,  struct hostent *hptr,
  99         char *buf, int buflen, int *h_errnop)
 100 {
 101         struct hostent *he = gethostbyname(name);
 102
 103         *h_errnop = h_errno;
 104
 105         if (he == NULL)
 106                 return NULL;
 107
 108         return copy_hostent(he, hptr, buf, buflen);
 109 }
 110
 111
 112 struct hostent *
 113 gethostbyaddr_r(const char *addr, int len, int type,
 114         struct hostent *hptr, char *buf, int buflen, int *h_errnop)
 115 {
 116         struct hostent *he = gethostbyaddr(addr, len, type);
 117
 118         *h_errnop = h_errno;
 119
 120     if (he == NULL)
 121         return NULL;
 122
 123     return copy_hostent(he, hptr, buf, buflen);
 124 }
 125