tinydns-edit.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include "stralloc.h"
   6 #include "buffer.h"
   7 #include "exit.h"
   8 #include "open.h"
   9 #include "getln.h"
  10 #include "strerr.h"
  11 #include "scan.h"
  12 #include "byte.h"
  13 #include "str.h"
  14 #include "fmt.h"
  15 #include "ip4.h"
  16 #include "dns.h"
  17
  18 #define FATAL "tinydns-edit: fatal: "
  19
  20 #define TTL_NS 259200
  21 #define TTL_POSITIVE 86400
  22
  23 char *fn;
  24 char *fnnew;
  25
  26 void die_usage()
  27 {
  28   strerr_die1x(100,"tinydns-edit: usage: tinydns-edit data data.new add [ns|childns|host|alias|mx] domain a.b.c.d");
  29 }
  30 void nomem()
  31 {
  32   strerr_die2x(111,FATAL,"out of memory");
  33 }
  34 void die_read()
  35 {
  36   strerr_die4sys(100,FATAL,"tinydns-edit: fatal: unable to read ",fn,": ");
  37 }
  38 void die_write()
  39 {
  40   strerr_die4sys(100,FATAL,"tinydns-edit: fatal: unable to write ",fnnew,": ");
  41 }
  42
  43 char mode;
  44 static char *target;
  45 char targetip[4];
  46
  47 int fd;
  48 buffer b;
  49 char bspace[1024];
  50
  51 int fdnew;
  52 buffer bnew;
  53 char bnewspace[1024];
  54
  55 static stralloc line;
  56 int match = 1;
  57
  58 #define NUMFIELDS 10
  59 static stralloc f[NUMFIELDS];
  60
  61 static char *d1;
  62 static char *d2;
  63 char ip[4];
  64 char ipstr[IP4_FMT];
  65 char strnum[FMT_ULONG];
  66
  67 static char *names[26];
  68 static int used[26];
  69
  70 void put(const char *buf,unsigned int len)
  71 {
  72   if (buffer_putalign(&bnew,buf,len) == -1) die_write();
  73 }
  74
  75 int main(int argc,char **argv)
  76 {
  77   unsigned long ttl;
  78   struct stat st;
  79   int i;
  80   int j;
  81   int k;
  82   char ch;
  83
  84   if (!*argv) die_usage();
  85
  86   if (!*++argv) die_usage();
  87   fn = *argv;
  88
  89   if (!*++argv) die_usage();
  90   fnnew = *argv;
  91
  92   if (!*++argv) die_usage();
  93   if (str_diff(*argv,"add")) die_usage();
  94
  95   if (!*++argv) die_usage();
  96   if (str_equal(*argv,"ns")) mode = '.';
  97   else if (str_equal(*argv,"childns")) mode = '&';
  98   else if (str_equal(*argv,"host")) mode = '=';
  99   else if (str_equal(*argv,"alias")) mode = '+';
 100   else if (str_equal(*argv,"mx")) mode = '@';
 101   else die_usage();
 102
 103   if (!*++argv) die_usage();
 104   if (!dns_domain_fromdot(&target,*argv,str_len(*argv))) nomem();
 105
 106   if (!*++argv) die_usage();
 107   if (!ip4_scan(*argv,targetip)) die_usage();
 108
 109   umask(077);
 110
 111   fd = open_read(fn);
 112   if (fd == -1) die_read();
 113   if (fstat(fd,&st) == -1) die_read();
 114   buffer_init(&b,buffer_unixread,fd,bspace,sizeof bspace);
 115
 116   fdnew = open_trunc(fnnew);
 117   if (fdnew == -1) die_write();
 118   if (fchmod(fdnew,st.st_mode & 0644) == -1) die_write();
 119   buffer_init(&bnew,buffer_unixwrite,fdnew,bnewspace,sizeof bnewspace);
 120
 121   switch(mode) {
 122     case '.': case '&':
 123       ttl = TTL_NS;
 124       for (i = 0;i < 26;++i) {
 125         ch = 'a' + i;
 126         if (!stralloc_copyb(&f[0],&ch,1)) nomem();
 127         if (!stralloc_cats(&f[0],".ns.")) nomem();
 128         if (!dns_domain_todot_cat(&f[0],target)) nomem();
 129         if (!dns_domain_fromdot(&names[i],f[0].s,f[0].len)) nomem();
 130       }
 131       break;
 132     case '+': case '=':
 133       ttl = TTL_POSITIVE;
 134       break;
 135     case '@':
 136       ttl = TTL_POSITIVE;
 137       for (i = 0;i < 26;++i) {
 138         ch = 'a' + i;
 139         if (!stralloc_copyb(&f[0],&ch,1)) nomem();
 140         if (!stralloc_cats(&f[0],".mx.")) nomem();
 141         if (!dns_domain_todot_cat(&f[0],target)) nomem();
 142         if (!dns_domain_fromdot(&names[i],f[0].s,f[0].len)) nomem();
 143       }
 144       break;
 145   }
 146
 147   while (match) {
 148     if (getln(&b,&line,&match,'\n') == -1) die_read();
 149
 150     put(line.s,line.len);
 151     if (line.len && !match) put("\n",1);
 152
 153     while (line.len) {
 154       ch = line.s[line.len - 1];
 155       if ((ch != ' ') && (ch != '\t') && (ch != '\n')) break;
 156       --line.len;
 157     }
 158     if (!line.len) continue;
 159     if (line.s[0] == '#') continue;
 160
 161     j = 1;
 162     for (i = 0;i < NUMFIELDS;++i) {
 163       if (j >= line.len) {
 164         if (!stralloc_copys(&f[i],"")) nomem();
 165       }
 166       else {
 167         k = byte_chr(line.s + j,line.len - j,':');
 168         if (!stralloc_copyb(&f[i],line.s + j,k)) nomem();
 169         j += k + 1;
 170       }
 171     }
 172
 173     switch(mode) {
 174       case '.': case '&':
 175         if (line.s[0] == mode) {
 176           if (!dns_domain_fromdot(&d1,f[0].s,f[0].len)) nomem();
 177           if (dns_domain_equal(d1,target)) {
 178             if (byte_chr(f[2].s,f[2].len,'.') >= f[2].len) {
 179               if (!stralloc_cats(&f[2],".ns.")) nomem();
 180               if (!stralloc_catb(&f[2],f[0].s,f[0].len)) nomem();
 181             }
 182             if (!dns_domain_fromdot(&d2,f[2].s,f[2].len)) nomem();
 183             if (!stralloc_0(&f[3])) nomem();
 184             if (!scan_ulong(f[3].s,&ttl)) ttl = TTL_NS;
 185             for (i = 0;i < 26;++i)
 186               if (dns_domain_equal(d2,names[i])) {
 187                 used[i] = 1;
 188                 break;
 189               }
 190           }
 191         }
 192         break;
 193
 194       case '=':
 195         if (line.s[0] == '=') {
 196           if (!dns_domain_fromdot(&d1,f[0].s,f[0].len)) nomem();
 197           if (dns_domain_equal(d1,target))
 198             strerr_die2x(100,FATAL,"host name already used");
 199           if (!stralloc_0(&f[1])) nomem();
 200           if (ip4_scan(f[1].s,ip))
 201             if (byte_equal(ip,4,targetip))
 202               strerr_die2x(100,FATAL,"IP address already used");
 203         }
 204         break;
 205
 206       case '@':
 207         if (line.s[0] == '@') {
 208           if (!dns_domain_fromdot(&d1,f[0].s,f[0].len)) nomem();
 209           if (dns_domain_equal(d1,target)) {
 210             if (byte_chr(f[2].s,f[2].len,'.') >= f[2].len) {
 211               if (!stralloc_cats(&f[2],".mx.")) nomem();
 212               if (!stralloc_catb(&f[2],f[0].s,f[0].len)) nomem();
 213             }
 214             if (!dns_domain_fromdot(&d2,f[2].s,f[2].len)) nomem();
 215             if (!stralloc_0(&f[4])) nomem();
 216             if (!scan_ulong(f[4].s,&ttl)) ttl = TTL_POSITIVE;
 217             for (i = 0;i < 26;++i)
 218               if (dns_domain_equal(d2,names[i])) {
 219                 used[i] = 1;
 220                 break;
 221               }
 222           }
 223         }
 224         break;
 225     }
 226   }
 227
 228   if (!stralloc_copyb(&f[0],&mode,1)) nomem();
 229   if (!dns_domain_todot_cat(&f[0],target)) nomem();
 230   if (!stralloc_cats(&f[0],":")) nomem();
 231   if (!stralloc_catb(&f[0],ipstr,ip4_fmt(ipstr,targetip))) nomem();
 232   switch(mode) {
 233     case '.': case '&': case '@':
 234       for (i = 0;i < 26;++i)
 235         if (!used[i])
 236           break;
 237       if (i >= 26)
 238         strerr_die2x(100,FATAL,"too many records for that domain");
 239       ch = 'a' + i;
 240       if (!stralloc_cats(&f[0],":")) nomem();
 241       if (!stralloc_catb(&f[0],&ch,1)) nomem();
 242       if (mode == '@')
 243         if (!stralloc_cats(&f[0],":")) nomem();
 244       break;
 245   }
 246   if (!stralloc_cats(&f[0],":")) nomem();
 247   if (!stralloc_catb(&f[0],strnum,fmt_ulong(strnum,ttl))) nomem();
 248   if (!stralloc_cats(&f[0],"\n")) nomem();
 249   put(f[0].s,f[0].len);
 250
 251   if (buffer_flush(&bnew) == -1) die_write();
 252   if (fsync(fdnew) == -1) die_write();
 253   if (close(fdnew) == -1) die_write(); /* NFS dorks */
 254   if (rename(fnnew,fn) == -1)
 255     strerr_die6sys(111,FATAL,"unable to move ",fnnew," to ",fn,": ");
 256   _exit(0);
 257 }