struct chan *devclone(struct chan *c)
{
struct chan *nc;
/* In plan 9, you couldn't clone an open chan. We're allowing it, possibly
* foolishly. The new chan is a non-open, "kernel internal" chan. Note
* that c->flag isn't set, for instance. c->mode is, which might be a
* problem. The newchan should eventually have a device's open called on
* it, at which point it upgrades from a kernel internal chan to one that
* can refer to an object in the device (e.g. grab a refcnt on a
* conversation in #ip).
*
* Either we allow devclones of open chans, or O_PATH walks do not open a
* file. It's nice to allow the device to do something for O_PATH, but
* perhaps that is not critical. However, if we can't clone an opened chan,
* then we can *only* openat from an FD that is O_PATH, which is not the
* spec (and not as useful). */
if ((c->flag & COPEN) && !(c->flag & O_PATH))
panic("clone of non-O_PATH open file type %s\n", devtab[c->type].name);
nc = newchan();
nc->type = c->type;
nc->dev = c->dev;
nc->mode = c->mode;
nc->qid = c->qid;
nc->offset = c->offset;
nc->umh = NULL;
nc->mountid = c->mountid;
nc->aux = c->aux;
nc->mqid = c->mqid;
nc->mcp = c->mcp;
return nc;
}
Chan*
devclone(Chan *c)
{
if (0) print_func_entry();
Chan *nc;
if(c->flag & COPEN){
panic("devclone: file of type %C already open\n",
c->dev != nil? c->dev->dc: -1);
}
nc = newchan();
/*
* The caller fills dev in if and when necessary.
nc->dev = nil; //XDYNXX
*/
nc->devno = c->devno;
nc->mode = c->mode;
nc->qid = c->qid;
nc->offset = c->offset;
nc->umh = nil;
nc->aux = c->aux;
nc->mqid = c->mqid;
nc->mc = c->mc;
if (0) print_func_exit();
return nc;
}
Chan*
devattach(int dc, char *spec)
{
if (0) print_func_entry();
Chan *c;
char *buf;
/*
* There are no error checks here because
* this can only be called from the driver of dc
* which pretty much guarantees devtabget will
* succeed.
*/
c = newchan();
mkqid(&c->qid, 0, 0, QTDIR);
c->dev = devtabget(dc, 0);
if(spec == nil)
spec = "";
buf = smalloc(1+UTFmax+strlen(spec)+1);
sprint(buf, "#%C%s", dc, spec);
c->path = newpath(buf);
free(buf);
if (0) print_func_exit();
return c;
}
Chan*
lfdchan(int fd)
{
Chan *c;
c = newchan();
c->type = devno('L', 0);
c->aux = (void*)(uintptr)fd;
c->name = newcname("fd");
c->mode = ORDWR;
c->qid.type = 0;
c->qid.path = 0;
c->qid.vers = 0;
c->dev = 0;
c->offset = 0;
return c;
}
Chan*
devattach(int tc, char *spec)
{
Chan *c;
char *buf;
c = newchan();
mkqid(&c->qid, 0, 0, QTDIR);
c->type = devno(tc, 0);
if(spec == nil)
spec = "";
buf = smalloc(4+strlen(spec)+1);
sprint(buf, "#%C%s", tc, spec);
c->name = newcname(buf);
free(buf);
return c;
}
struct chan *devattach(int tc, char *spec)
{
struct chan *c;
char *buf;
c = newchan();
mkqid(&c->qid, 0, 0, QTDIR);
c->type = devno(tc, 0);
if (spec == NULL)
spec = "";
/* 2 for #c, 1 for \0 */
buf = kzmalloc(2 + strlen(spec) + 1, KMALLOC_WAIT);
snprintf(buf, sizeof(buf), "#%c%s", tc, spec);
c->name = newcname(buf);
kfree(buf);
return c;
}
struct chan *devattach(const char *name, char *spec)
{
struct chan *c;
char *buf;
size_t buflen;
c = newchan();
mkqid(&c->qid, 0, 0, QTDIR);
c->type = devno(name, 0);
if (spec == NULL)
spec = "";
/* 1 for #, 1 for ., 1 for \0 */
buflen = strlen(name) + strlen(spec) + 3;
buf = kzmalloc(buflen, KMALLOC_WAIT);
snprintf(buf, sizeof(buf), "#%s.%s", name, spec);
c->name = newcname(buf);
kfree(buf);
return c;
}
Chan*
devclone(Chan *c)
{
Chan *nc;
if(c->flag & COPEN)
panic("clone of open file type %C\n", devtab[c->type]->dc);
nc = newchan();
nc->type = c->type;
nc->dev = c->dev;
nc->mode = c->mode;
nc->qid = c->qid;
nc->offset = c->offset;
nc->umh = nil;
nc->mountid = c->mountid;
nc->aux = c->aux;
nc->mqid = c->mqid;
nc->mcp = c->mcp;
return nc;
}
