sys/src/cmd/ndb/dnsquery.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <bio.h>
   4 #include <ctype.h>
   5 #include <ndb.h>
   6 #include "dns.h"
   7 #include "ip.h"
   8
   9 static int domount;
  10 static char *mtpt, *dns, *srv;
  11
  12 static int
  13 setup(int argc, char **argv)
  14 {
  15         int fd;
  16
  17         if(argc == 1){
  18                 domount = 0;
  19                 mtpt = argv[0];
  20         }
  21
  22         fd = open(dns, ORDWR);
  23         if(fd < 0){
  24                 if(domount == 0)
  25                         sysfatal("can't open %s: %r", dns);
  26                 fd = open(srv, ORDWR);
  27                 if(fd < 0)
  28                         sysfatal("can't open %s: %r", srv);
  29                 if(mount(fd, -1, mtpt, MBEFORE, "") < 0)
  30                         sysfatal("can't mount(%s, %s): %r", srv, mtpt);
  31                 fd = open(dns, ORDWR);
  32                 if(fd < 0)
  33                         sysfatal("can't open %s: %r", dns);
  34         }
  35         return fd;
  36 }
  37
  38 static void
  39 querydns(int fd, char *line, int n)
  40 {
  41         char buf[1024];
  42
  43         seek(fd, 0, 0);
  44         if(write(fd, line, n) != n) {
  45                 print("!%r\n");
  46                 return;
  47         }
  48         seek(fd, 0, 0);
  49         buf[0] = '\0';
  50         while((n = read(fd, buf, sizeof(buf))) > 0){
  51                 buf[n] = '\0';
  52                 print("%s\n", buf);
  53         }
  54 }
  55
  56 static void
  57 query(int fd)
  58 {
  59         int n, len;
  60         char *lp, *p, *np;
  61         char buf[1024], line[1024];
  62         Biobuf in;
  63
  64         Binit(&in, 0, OREAD);
  65         for(print("> "); lp = Brdline(&in, '\n'); print("> ")){
  66                 n = Blinelen(&in) -1;
  67                 while(isspace(lp[n]))
  68                         lp[n--] = 0;
  69                 n++;
  70                 while(isspace(*lp)){
  71                         lp++;
  72                         n--;
  73                 }
  74                 if(!*lp)
  75                         continue;
  76                 strcpy(line, lp);
  77
  78                 /* default to an "ip" request if alpha, "ptr" if numeric */
  79                 if(strchr(line, ' ') == nil)
  80                         if(strcmp(ipattr(line), "ip") == 0) {
  81                                 strcat(line, " ptr");
  82                                 n += 4;
  83                         } else {
  84                                 strcat(line, " ip");
  85                                 n += 3;
  86                         }
  87
  88                 /* inverse queries may need to be permuted */
  89                 if(n > 4 && strcmp(" ptr", &line[n-4]) == 0 &&
  90                     cistrstr(line, ".arpa") == nil){
  91                         /* TODO: reversing v6 addrs is harder */
  92                         for(p = line; *p; p++)
  93                                 if(*p == ' '){
  94                                         *p = '.';
  95                                         break;
  96                                 }
  97                         np = buf;
  98                         len = 0;
  99                         while(p >= line){
 100                                 len++;
 101                                 p--;
 102                                 if(*p == '.'){
 103                                         memmove(np, p+1, len);
 104                                         np += len;
 105                                         len = 0;
 106                                 }
 107                         }
 108                         memmove(np, p+1, len);
 109                         np += len;
 110                         strcpy(np, "in-addr.arpa ptr"); /* TODO: ip6.arpa for v6 */
 111                         strcpy(line, buf);
 112                         n = strlen(line);
 113                 }
 114
 115                 querydns(fd, line, n);
 116         }
 117         Bterm(&in);
 118 }
 119
 120 void
 121 main(int argc, char *argv[])
 122 {
 123         mtpt = "/net";
 124         dns = "/net/dns";
 125         srv = "/srv/dns";
 126         domount = 1;
 127         ARGBEGIN {
 128         case 'x':
 129                 mtpt = "/net.alt";
 130                 dns = "/net.alt/dns";
 131                 srv = "/srv/dns_net.alt";
 132                 break;
 133         default:
 134                 fprint(2, "usage: %s [-x] [dns-mount-point]\n", argv0);
 135                 exits("usage");
 136         } ARGEND;
 137
 138         query(setup(argc, argv));
 139         exits(0);
 140 }