sys/src/libventi/version.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <venti.h>
   4
   5 static char *okvers[] = {
   6         "02",
   7         nil,
   8 };
   9
  10 /*
  11 static char EBigString[] = "string too long";
  12 static char EBigPacket[] = "packet too long";
  13 static char ENullString[] = "missing string";
  14 */
  15 static char EBadVersion[] = "bad format in version string";
  16
  17 static int
  18 vtreadversion(VtConn *z, char *q, char *v, int nv)
  19 {
  20         int n;
  21
  22         for(;;){
  23                 if(nv <= 1){
  24                         werrstr("version too long");
  25                         return -1;
  26                 }
  27                 n = read(z->infd, v, 1);
  28                 if(n <= 0){
  29                         if(n == 0)
  30                                 werrstr("unexpected eof");
  31                         return -1;
  32                 }
  33                 if(*v == '\n'){
  34                         *v = 0;
  35                         break;
  36                 }
  37                 if((uchar)*v < ' ' || (uchar)*v > 0x7f || (*q && *v != *q)){
  38                         werrstr(EBadVersion);
  39                         return -1;
  40                 }
  41                 v++;
  42                 nv--;
  43                 if(*q)
  44                         q++;
  45         }
  46         return 0;
  47 }
  48
  49 int
  50 vtversion(VtConn *z)
  51 {
  52         char buf[VtMaxStringSize], *p, *ep, *prefix, *pp;
  53         int i;
  54
  55         qlock(&z->lk);
  56         if(z->state != VtStateAlloc){
  57                 werrstr("bad session state");
  58                 qunlock(&z->lk);
  59                 return -1;
  60         }
  61
  62         qlock(&z->inlk);
  63         qlock(&z->outlk);
  64
  65         p = buf;
  66         ep = buf + sizeof buf;
  67         prefix = "venti-";
  68         p = seprint(p, ep, "%s", prefix);
  69         p += strlen(p);
  70         for(i=0; okvers[i]; i++)
  71                 p = seprint(p, ep, "%s%s", i ? ":" : "", okvers[i]);
  72         p = seprint(p, ep, "-libventi\n");
  73         assert(p-buf < sizeof buf);
  74
  75         if(write(z->outfd, buf, p-buf) != p-buf)
  76                 goto Err;
  77         vtdebug(z, "version string out: %s", buf);
  78
  79         if(vtreadversion(z, prefix, buf, sizeof buf) < 0)
  80                 goto Err;
  81         vtdebug(z, "version string in: %s", buf);
  82
  83         p = buf+strlen(prefix);
  84         for(; *p; p=pp){
  85                 if(*p == ':' || *p == '-')
  86                         p++;
  87                 pp = strpbrk(p, ":-");
  88                 if(pp == nil)
  89                         pp = p+strlen(p);
  90                 for(i=0; okvers[i]; i++)
  91                         if(strlen(okvers[i]) == pp-p && memcmp(okvers[i], p, pp-p) == 0){
  92                                 *pp = 0;
  93                                 z->version = vtstrdup(p);
  94                                 goto Okay;
  95                         }
  96         }
  97         werrstr("unable to negotiate version");
  98         goto Err;
  99
 100 Okay:
 101         z->state = VtStateConnected;
 102         qunlock(&z->inlk);
 103         qunlock(&z->outlk);
 104         qunlock(&z->lk);
 105         return 0;
 106
 107 Err:
 108         werrstr("vtversion: %r");
 109         if(z->infd >= 0)
 110                 close(z->infd);
 111         if(z->outfd >= 0 && z->outfd != z->infd)
 112                 close(z->outfd);
 113         z->infd = -1;
 114         z->outfd = -1;
 115         z->state = VtStateClosed;
 116         qunlock(&z->inlk);
 117         qunlock(&z->outlk);
 118         qunlock(&z->lk);
 119         return -1;
 120 }