sys/src/ape/lib/bsd/gethostbyname.c

   1 /* posix */
   2 #include <sys/types.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <fcntl.h>
   7 #include <string.h>
   8 #include <errno.h>
   9
  10 /* bsd extensions */
  11 #include <sys/uio.h>
  12 #include <sys/socket.h>
  13 #include <netinet/in.h>
  14 #include <netdb.h>
  15
  16 #include "priv.h"
  17
  18 int h_errno;
  19
  20 enum
  21 {
  22         Nname= 6,
  23 };
  24
  25 /*
  26  *  for inet addresses only
  27  */
  28 struct hostent*
  29 gethostbyname(char *name)
  30 {
  31         int i, t, fd, m;
  32         char *p, *bp;
  33         int nn, na;
  34         unsigned long x;
  35         static struct hostent h;
  36         static char buf[1024];
  37         static char *nptr[Nname+1];
  38         static char *aptr[Nname+1];
  39         static char addr[Nname][4];
  40
  41         h.h_name = 0;
  42         t = _sock_ipattr(name);
  43
  44         /* connect to server */
  45         fd = open("/net/cs", O_RDWR);
  46         if(fd < 0){
  47                 _syserrno();
  48                 h_errno = NO_RECOVERY;
  49                 return 0;
  50         }
  51
  52         /* construct the query, always expect an ip# back */
  53         switch(t){
  54         case Tsys:
  55                 snprintf(buf, sizeof buf, "!sys=%s ip=*", name);
  56                 break;
  57         case Tdom:
  58                 snprintf(buf, sizeof buf, "!dom=%s ip=*", name);
  59                 break;
  60         case Tip:
  61                 snprintf(buf, sizeof buf, "!ip=%s", name);
  62                 break;
  63         }
  64
  65         /* query the server */
  66         if(write(fd, buf, strlen(buf)) < 0){
  67                 _syserrno();
  68                 h_errno = TRY_AGAIN;
  69                 return 0;
  70         }
  71         lseek(fd, 0, 0);
  72         for(i = 0; i < sizeof(buf)-1; i += m){
  73                 m = read(fd, buf+i, sizeof(buf) - 1 - i);
  74                 if(m <= 0)
  75                         break;
  76                 buf[i+m++] = ' ';
  77         }
  78         close(fd);
  79         buf[i] = 0;
  80
  81         /* parse the reply */
  82         nn = na = 0;
  83         for(bp = buf;;){
  84                 p = strchr(bp, '=');
  85                 if(p == 0)
  86                         break;
  87                 *p++ = 0;
  88                 if(strcmp(bp, "dom") == 0){
  89                         if(h.h_name == 0)
  90                                 h.h_name = p;
  91                         if(nn < Nname)
  92                                 nptr[nn++] = p;
  93                 } else if(strcmp(bp, "sys") == 0){
  94                         if(nn < Nname)
  95                                 nptr[nn++] = p;
  96                 } else if(strcmp(bp, "ip") == 0){
  97                         x = inet_addr(p);
  98                         x = ntohl(x);
  99                         if(na < Nname){
 100                                 addr[na][0] = x>>24;
 101                                 addr[na][1] = x>>16;
 102                                 addr[na][2] = x>>8;
 103                                 addr[na][3] = x;
 104                                 aptr[na] = addr[na];
 105                                 na++;
 106                         }
 107                 }
 108                 while(*p && *p != ' ')
 109                         p++;
 110                 if(*p)
 111                         *p++ = 0;
 112                 bp = p;
 113         }
 114         if(nn+na == 0){
 115                 h_errno = HOST_NOT_FOUND;
 116                 return 0;
 117         }
 118
 119         nptr[nn] = 0;
 120         aptr[na] = 0;
 121         h.h_aliases = nptr;
 122         h.h_addr_list = aptr;
 123         h.h_length = 4;
 124         h.h_addrtype = AF_INET;
 125         if(h.h_name == 0)
 126                 h.h_name = nptr[0];
 127         if(h.h_name == 0)
 128                 h.h_name = aptr[0];
 129
 130         return &h;
 131 }