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                 b->error = nil;
  34                 if(b->op & BWRITE){
  35                         memset(buf, 0, sizeof(buf));
  36                         pack(b, buf);
  37                         if(pwrite(d->fd, buf, BLOCK, b->off*BLOCK) < BLOCK){
  38                                 dprint("write: %r\n");
  39                                 b->error = Eio;
  40                         }
  41                 }else{
  42                         int n, m;
  43
  44                         for(n = 0; n < BLOCK; n += m){
  45                                 m = pread(d->fd, buf+n, BLOCK-n, b->off*BLOCK+n);
  46                                 if(m < 0)
  47                                         dprint("read: %r\n");
  48                                 if(m <= 0)
  49                                         break;
  50                         }
  51                         if(n < BLOCK)
  52                                 b->error = Eio;
  53                         else
  54                                 unpack(b, buf);
  55                 }
  56         reply:
  57                 r = b->resp;
  58                 b->resp = nil;
  59                 if(r != nil)
  60                         send(r, &b);
  61         }
  62 }
  63
  64 Dev *
  65 newdev(char *file)
  66 {
  67         Dev *d, **e;
  68         Dir *dir;
  69         Buf *b;
  70
  71         d = emalloc(sizeof(*d));
  72         d->fd = open(file, ORDWR);
  73         if(d->fd < 0){
  74                 free(d);
  75                 return nil;
  76         }
  77         dir = dirfstat(d->fd);
  78         if(dir == nil){
  79         error:
  80                 close(d->fd);
  81                 free(d);
  82                 return nil;
  83         }
  84         d->size = dir->length / BLOCK;
  85         free(dir);
  86         if(d->size == 0){
  87                 werrstr("device file too short");
  88                 goto error;
  89         }
  90         d->name = estrdup(file);
  91         for(b = d->buf; b < d->buf + BUFHASH + 1; b++)
  92                 b->dnext = b->dprev = b;
  93         d->workr.l = &d->workl;
  94         d->work.wnext = d->work.wprev = &d->work;
  95         proccreate(devwork, d, mainstacksize);
  96         for(e = &devs; *e != nil; e = &(*e)->next)
  97                 ;
  98         *e = d;
  99         return d;
 100 }