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                 return -1;
  45         if(n < 0){
  46                 clog("xmesg read error: %r\n");
  47                 return -1;
  48         }
  49         if(convM2S(s->data, n, &s->f) != n){
  50                 clog("xmesg bad convM2S %d %.2x %.2x %.2x %.2x\n",
  51                         n, ((uchar*)s->data)[0], ((uchar*)s->data)[1],
  52                         ((uchar*)s->data)[2], ((uchar*)s->data)[3]);
  53                 return -1;
  54         }
  55         if(p9debug)
  56                 fprint(2, "\trecv %F\n", &s->f);
  57         if(s->f.tag != s->tag){
  58                 clog("xmesg tag %d for %d\n", s->f.tag, s->tag);
  59                 goto again;
  60         }
  61         if(s->f.type == Rerror){
  62                 if(t == Tclunk)
  63                         clog("xmesg clunk: %s", s->f.ename);
  64                 chat("xmesg %d error %s...", t, s->f.ename);
  65                 return -1;
  66         }
  67         if(s->f.type != t+1){
  68                 clog("xmesg type mismatch: %d, expected %d\n", s->f.type, t+1);
  69                 return -1;
  70         }
  71         return 0;
  72 }
  73
  74 int
  75 clunkfid(Session *s, Fid *f)
  76 {
  77         putfid(s, f);
  78         if(s == 0 || f == 0)
  79                 return 0;
  80         s->f.fid = f - s->fids;
  81         return xmesg(s, Tclunk);
  82 }
  83
  84 #define UNLINK(p)       ((p)->prev->next = (p)->next, (p)->next->prev = (p)->prev)
  85
  86 #define LINK(h, p)      ((p)->next = (h)->next, (p)->prev = (h), \
  87                          (h)->next->prev = (p), (h)->next = (p))
  88
  89 #define TOFRONT(h, p)   ((h)->next != (p) ? (UNLINK(p), LINK(h,p)) : 0)
  90
  91 Fid *
  92 newfid(Session *s)
  93 {
  94         Fid *f, *fN;
  95
  96         chat("newfid..");
  97         if(s->list.prev == 0){
  98                 chat("init..");
  99                 s->list.prev = &s->list;
 100                 s->list.next = &s->list;
 101                 s->free = s->fids;
 102                 if(0 && chatty)
 103                         fN = &s->fids[25];
 104                 else
 105                         fN = &s->fids[nelem(s->fids)];
 106                 for(f=s->fids; f<fN; f++){
 107                         f->owner = 0;
 108                         f->prev = 0;
 109                         f->next = f+1;
 110                 }
 111                 (f-1)->next = 0;
 112         }
 113         if(s->free){
 114                 f = s->free;
 115                 s->free = f->next;
 116                 LINK(&s->list, f);
 117         }else{
 118                 for(f=s->list.prev; f!=&s->list; f=f->prev)
 119                         if(f->owner)
 120                                 break;
 121                 if(f == &s->list){
 122                         clog("fid leak");
 123                         return 0;
 124                 }
 125                 setfid(s, f);
 126                 if(xmesg(s, Tclunk) < 0){
 127                         clog("clunk failed, no fids?");
 128                         /*return 0;*/
 129                 }
 130                 *(f->owner) = 0;
 131                 f->owner = 0;
 132         }
 133         chat("%zd...", f - s->fids);
 134         f->tstale = nfstime + staletime;
 135         return f;
 136 }
 137
 138 void
 139 setfid(Session *s, Fid *f)
 140 {
 141         /*
 142          * TOFRONT(&s->list, f);
 143          */
 144         if(s->list.next != f){
 145                 UNLINK(f);
 146                 LINK(&s->list, f);
 147         }
 148
 149         f->tstale = nfstime + staletime;
 150         s->f.fid = f - s->fids;
 151 }
 152
 153 void
 154 putfid(Session *s, Fid *f)
 155 {
 156         chat("putfid %zd...", f-s->fids);
 157         if(s == 0 || f == 0){
 158                 clog("putfid(0x%p, 0x%p) %s", s, f, (s ? s->service : "?"));
 159                 return;
 160         }
 161         UNLINK(f);
 162         if(f->owner)
 163                 *(f->owner) = 0;
 164         f->owner = 0;
 165         f->prev = 0;
 166         f->next = s->free;
 167         s->free = f;
 168 }
 169
 170 void
 171 fidtimer(Session *s, long now)
 172 {
 173         Fid *f, *t;
 174         int n;
 175
 176         f = s->list.next;
 177         n = 0;
 178         while(f != &s->list){
 179                 t = f;
 180                 f = f->next;
 181                 if(t->owner && now >= t->tstale)
 182                         ++n, clunkfid(s, t);
 183         }
 184         if(n > 0)
 185                 chat("fidtimer %s\n", s->service);
 186 }