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

   1 #include "all.h"
   2
   3 static Xfile *  xflfree;
   4 static Xfid *   xfdfree;
   5
   6 #define FIDMOD  127     /* prime */
   7
   8 static Xfile    *xfiles[FIDMOD];
   9 static Lock     xlocks[FIDMOD];
  10
  11 Xfile *
  12 xfile(Qid *qid, void *s, int new)
  13 {
  14         int k;
  15         Xfile **hp, *f, *pf;
  16
  17         k = ((ulong)qid->path ^ (((u32int)(uintptr)s)<<24))%FIDMOD;
  18         hp = &xfiles[k];
  19
  20         lock(&xlocks[k]);
  21         for(f=*hp, pf=0; f; pf=f, f=f->next)
  22                 if(f->qid.path == qid->path
  23                 && (u32int)(uintptr)f->s == (u32int)(uintptr)s)
  24                         break;
  25         if(f && pf){
  26                 pf->next = f->next;
  27                 f->next = *hp;
  28                 *hp = f;
  29         }
  30         if(new < 0 && f){
  31                 *hp = f->next;
  32                 f->next = xflfree;
  33                 xflfree = f;
  34                 f = 0;
  35         }
  36         if(new > 0 && !f){
  37                 if(!(f = xflfree))      /* assign = */
  38                         f = listalloc(1024/sizeof(Xfile), sizeof(Xfile));
  39                 xflfree = f->next;
  40                 memset(f, 0, sizeof(Xfile));
  41                 f->next = *hp;
  42                 *hp = f;
  43                 f->qid = *qid;
  44                 f->s = s;
  45         }
  46         unlock(&xlocks[k]);
  47         return f;
  48 }
  49
  50 Xfid *
  51 xfid(char *uid, Xfile *xp, int new)
  52 {
  53         Xfid *f, *pf;
  54
  55         for(f=xp->users, pf=0; f; pf=f, f=f->next)
  56                 if(f->uid[0] == uid[0] && strcmp(f->uid, uid) == 0)
  57                         break;
  58         if(f && pf){
  59                 pf->next = f->next;
  60                 f->next = xp->users;
  61                 xp->users = f;
  62         }
  63         if(new < 0 && f){
  64                 if(f->urfid)
  65                         clunkfid(xp->s, f->urfid);
  66                 if(f->opfid)
  67                         clunkfid(xp->s, f->opfid);
  68                 xp->users = f->next;
  69                 f->next = xfdfree;
  70                 xfdfree = f;
  71                 f = 0;
  72         }
  73         if(new > 0 && !f){
  74                 if(!(f = xfdfree))      /* assign = */
  75                         f = listalloc(1024/sizeof(Xfid), sizeof(Xfid));
  76                 xfdfree = f->next;
  77                 memset(f, 0, sizeof(Xfid));
  78                 f->next = xp->users;
  79                 xp->users = f;
  80                 f->xp = xp;
  81                 f->uid = strstore(uid);
  82                 f->urfid = 0;
  83                 f->opfid = 0;
  84         }
  85         return f;
  86 }
  87
  88 int
  89 xfpurgeuid(Session *s, char *uid)
  90 {
  91         Xfile **hp, *f;
  92         Xfid *xf;
  93         int k, count=0;
  94
  95         for(k=0; k<FIDMOD; k++){
  96                 lock(&xlocks[k]);
  97                 hp=&xfiles[k];
  98                 for(f=*hp; f; f=f->next)
  99                         if(f->s == s && (xf = xfid(uid, f, 0))){ /* assign = */
 100                                 xfclear(xf);
 101                                 ++count;
 102                         }
 103                 unlock(&xlocks[k]);
 104         }
 105         return count;
 106 }