ref: ac98922f44c3df8839f1bdd07f23fcccf27d0cba
dir: /sys/src/cmd/hjfs/dev.c/
#include <u.h> #include <libc.h> #include <thread.h> #include "dat.h" #include "fns.h" Dev *devs; void devwork(void *v) { Dev *d; Buf *b; Channel *r; uchar buf[BLOCK]; d = v; for(;;){ qlock(&d->workl); while(d->work.wnext == &d->work) rsleep(&d->workr); b = d->work.wnext; b->wnext->wprev = b->wprev; b->wprev->wnext = b->wnext; b->wnext = b->wprev = nil; qunlock(&d->workl); if(b->d == nil) /* this is a sync request */ goto reply; if(b->off >= d->size){ b->error = Einval; goto reply; } b->error = nil; if(b->op & BWRITE){ memset(buf, 0, sizeof(buf)); pack(b, buf); if(pwrite(d->fd, buf, BLOCK, b->off*BLOCK) < BLOCK){ dprint("write: %r\n"); b->error = Eio; } }else{ int n, m; for(n = 0; n < BLOCK; n += m){ m = pread(d->fd, buf+n, BLOCK-n, b->off*BLOCK+n); if(m < 0) dprint("read: %r\n"); if(m <= 0) break; } if(n < BLOCK) b->error = Eio; else unpack(b, buf); } reply: r = b->resp; b->resp = nil; if(r != nil) send(r, &b); } } Dev * newdev(char *file) { Dev *d, **e; Dir *dir; Buf *b; d = emalloc(sizeof(*d)); d->fd = open(file, ORDWR); if(d->fd < 0){ free(d); return nil; } dir = dirfstat(d->fd); if(dir == nil){ error: close(d->fd); free(d); return nil; } d->size = dir->length / BLOCK; free(dir); if(d->size == 0){ werrstr("device file too short"); goto error; } d->name = estrdup(file); for(b = d->buf; b < d->buf + BUFHASH + 1; b++) b->dnext = b->dprev = b; d->workr.l = &d->workl; d->work.wnext = d->work.wprev = &d->work; proccreate(devwork, d, mainstacksize); for(e = &devs; *e != nil; e = &(*e)->next) ; *e = d; return d; }