sys/src/cmd/hjfs/dev.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <thread.h>
   4 #include "dat.h"
   5 #include "fns.h"
   6
   7 Dev *devs;
   8
   9 void
  10 devwork(void *v)
  11 {
  12         Dev *d;
  13         Buf *b;
  14         Channel *r;
  15         uchar buf[BLOCK];
  16
  17         d = v;
  18         for(;;){
  19                 qlock(&d->workl);
  20                 while(d->work.wnext == &d->work)
  21                         rsleep(&d->workr);
  22                 b = d->work.wnext;
  23                 b->wnext->wprev = b->wprev;
  24                 b->wprev->wnext = b->wnext;
  25                 b->wnext = b->wprev = nil;
  26                 qunlock(&d->workl);
  27                 if(b->d == nil) /* this is a sync request */
  28                         goto reply;
  29                 if(b->off >= d->size){
  30                         b->error = Einval;
  31                         goto reply;
  32                 }
  33                 seek(d->fd, b->off * BLOCK, 0);
  34                 b->error = nil;
  35                 if(b->op & BWRITE){
  36                         memset(buf, 0, sizeof(buf));
  37                         pack(b, buf);
  38                         if(write(d->fd, buf, BLOCK) < BLOCK){
  39                                 dprint("hjfs: write: %r\n");
  40                                 b->error = Eio;
  41                         }
  42                 }else{
  43                         if(readn(d->fd, buf, BLOCK) < 0){
  44                                 dprint("hjfs: read: %r\n");
  45                                 b->error = Eio;
  46                         }else
  47                                 unpack(b, buf);
  48                 }
  49         reply:
  50                 r = b->resp;
  51                 b->resp = nil;
  52                 if(r != nil)
  53                         send(r, &b);
  54         }
  55 }
  56
  57 Dev *
  58 newdev(char *file)
  59 {
  60         Dev *d, **e;
  61         Dir *dir;
  62         Buf *b;
  63
  64         d = emalloc(sizeof(*d));
  65         d->fd = open(file, ORDWR);
  66         if(d->fd < 0){
  67                 free(d);
  68                 return nil;
  69         }
  70         dir = dirfstat(d->fd);
  71         if(dir == nil){
  72         error:
  73                 close(d->fd);
  74                 free(d);
  75                 return nil;
  76         }
  77         d->size = dir->length / BLOCK;
  78         free(dir);
  79         if(d->size == 0){
  80                 werrstr("device file too short");
  81                 goto error;
  82         }
  83         d->name = estrdup(file);
  84         for(b = d->buf; b < d->buf + BUFHASH + 1; b++)
  85                 b->dnext = b->dprev = b;
  86         d->workr.l = &d->workl;
  87         d->work.wnext = d->work.wprev = &d->work;
  88         proccreate(devwork, d, mainstacksize);
  89         for(e = &devs; *e != nil; e = &(*e)->next)
  90                 ;
  91         *e = d;
  92         return d;
  93 }