sys/src/cmd/9nfs/9p.c

   1 #include "all.h"
   2
   3 static char *tnames[] = {
   4         [Tversion]      "version",
   5         [Tauth]         "auth",
   6         [Tattach]       "attach",
   7         [Tflush]        "flush",
   8         [Twalk]         "walk",
   9         [Topen]         "open",
  10         [Tcreate]       "create",
  11         [Tread]         "read",
  12         [Twrite]        "write",
  13         [Tclunk]        "clunk",
  14         [Tremove]       "remove",
  15         [Tstat]         "stat",
  16         [Twstat]        "wstat",
  17 };
  18
  19 int     messagesize = IOHDRSZ+Maxfdata;
  20
  21 int
  22 xmesg(Session *s, int t)
  23 {
  24         int n;
  25
  26         if(chatty){
  27                 if(0 <= t && t < nelem(tnames) && tnames[t])
  28                         chat("T%s...", tnames[t]);
  29                 else
  30                         chat("T%d...", t);
  31         }
  32         s->f.type = t;
  33         s->f.tag = ++s->tag;
  34         if(p9debug)
  35                 fprint(2, "xmseg\tsend %F\n", &s->f);
  36         n = convS2M(&s->f, s->data, messagesize);
  37         if(niwrite(s->fd, s->data, n) != n){
  38                 clog("xmesg write error on %d: %r\n", s->fd);
  39                 return -1;
  40         }
  41 again:
  42         n = read9pmsg(s->fd, s->data, messagesize);
  43         if(n < 0){
  44                 clog("xmesg read error: %r\n");
  45                 return -1;
  46         }
  47         if(convM2S(s->data, n, &s->f) <= 0){
  48                 clog("xmesg bad convM2S %d %.2x %.2x %.2x %.2x\n",
  49                         n, ((uchar*)s->data)[0], ((uchar*)s->data)[1],
  50                         ((uchar*)s->data)[2], ((uchar*)s->data)[3]);
  51                 return -1;
  52         }
  53         if(p9debug)
  54                 fprint(2, "\trecv %F\n", &s->f);
  55         if(s->f.tag != s->tag){
  56                 clog("xmesg tag %d for %d\n", s->f.tag, s->tag);
  57                 goto again;
  58         }
  59         if(s->f.type == Rerror){
  60                 if(t == Tclunk)
  61                         clog("xmesg clunk: %s", s->f.ename);
  62                 chat("xmesg %d error %s...", t, s->f.ename);
  63                 return -1;
  64         }
  65         if(s->f.type != t+1){
  66                 clog("xmesg type mismatch: %d, expected %d\n", s->f.type, t+1);
  67                 return -1;
  68         }
  69         return 0;
  70 }
  71
  72 int
  73 clunkfid(Session *s, Fid *f)
  74 {
  75         putfid(s, f);
  76         if(s == 0 || f == 0)
  77                 return 0;
  78         s->f.fid = f - s->fids;
  79         return xmesg(s, Tclunk);
  80 }
  81
  82 #define UNLINK(p)       ((p)->prev->next = (p)->next, (p)->next->prev = (p)->prev)
  83
  84 #define LINK(h, p)      ((p)->next = (h)->next, (p)->prev = (h), \
  85                          (h)->next->prev = (p), (h)->next = (p))
  86
  87 #define TOFRONT(h, p)   ((h)->next != (p) ? (UNLINK(p), LINK(h,p)) : 0)
  88
  89 Fid *
  90 newfid(Session *s)
  91 {
  92         Fid *f, *fN;
  93
  94         chat("newfid..");
  95         if(s->list.prev == 0){
  96                 chat("init..");
  97                 s->list.prev = &s->list;
  98                 s->list.next = &s->list;
  99                 s->free = s->fids;
 100                 if(0 && chatty)
 101                         fN = &s->fids[25];
 102                 else
 103                         fN = &s->fids[nelem(s->fids)];
 104                 for(f=s->fids; f<fN; f++){
 105                         f->owner = 0;
 106                         f->prev = 0;
 107                         f->next = f+1;
 108                 }
 109                 (f-1)->next = 0;
 110         }
 111         if(s->free){
 112                 f = s->free;
 113                 s->free = f->next;
 114                 LINK(&s->list, f);
 115         }else{
 116                 for(f=s->list.prev; f!=&s->list; f=f->prev)
 117                         if(f->owner)
 118                                 break;
 119                 if(f == &s->list){
 120                         clog("fid leak");
 121                         return 0;
 122                 }
 123                 setfid(s, f);
 124                 if(xmesg(s, Tclunk) < 0){
 125                         clog("clunk failed, no fids?");
 126                         /*return 0;*/
 127                 }
 128                 *(f->owner) = 0;
 129                 f->owner = 0;
 130         }
 131         chat("%ld...", f - s->fids);
 132         f->tstale = nfstime + staletime;
 133         return f;
 134 }
 135
 136 void
 137 setfid(Session *s, Fid *f)
 138 {
 139         /*
 140          * TOFRONT(&s->list, f);
 141          */
 142         if(s->list.next != f){
 143                 UNLINK(f);
 144                 LINK(&s->list, f);
 145         }
 146
 147         f->tstale = nfstime + staletime;
 148         s->f.fid = f - s->fids;
 149 }
 150
 151 void
 152 putfid(Session *s, Fid *f)
 153 {
 154         chat("putfid %ld...", f-s->fids);
 155         if(s == 0 || f == 0){
 156                 clog("putfid(0x%p, 0x%p) %s", s, f, (s ? s->service : "?"));
 157                 return;
 158         }
 159         UNLINK(f);
 160         if(f->owner)
 161                 *(f->owner) = 0;
 162         f->owner = 0;
 163         f->prev = 0;
 164         f->next = s->free;
 165         s->free = f;
 166 }
 167
 168 void
 169 fidtimer(Session *s, long now)
 170 {
 171         Fid *f, *t;
 172         int n;
 173
 174         f = s->list.next;
 175         n = 0;
 176         while(f != &s->list){
 177                 t = f;
 178                 f = f->next;
 179                 if(t->owner && now >= t->tstale)
 180                         ++n, clunkfid(s, t);
 181         }
 182         if(n > 0)
 183                 chat("fidtimer %s\n", s->service);
 184 }