static Chan*
segmentopen(Chan *c, int omode)
{
Globalseg *g;
switch(TYPE(c)){
case Qtopdir:
case Qsegdir:
if(omode != 0)
error(Eisdir);
break;
case Qctl:
case Qfree:
g = getgseg(c);
if(waserror()){
putgseg(g);
nexterror();
}
devpermcheck(g->uid, g->perm, omode);
c->aux = g;
poperror();
c->flag |= COPEN;
break;
case Qdata:
g = getgseg(c);
if(waserror()){
putgseg(g);
nexterror();
}
devpermcheck(g->uid, g->perm, omode);
if(g->s == nil)
error("segment not yet allocated");
if(g->kproc == nil){
qlock(&g->l);
if(waserror()){
qunlock(&g->l);
nexterror();
}
if(g->kproc == nil){
g->cmd = Cnone;
kproc(g->name, segmentkproc, g);
docmd(g, Cstart);
}
poperror();
qunlock(&g->l);
}
c->aux = g;
poperror();
c->flag |= COPEN;
break;
default:
panic("segmentopen");
}
c->mode = openmode(omode);
c->offset = 0;
return c;
}
/*
* called by segattach()
*/
static Segment*
globalsegattach(Proc *p, char *name)
{
int x;
Globalseg *g;
Segment *s;
g = nil;
if(waserror()){
unlock(&globalseglock);
nexterror();
}
lock(&globalseglock);
for(x = 0; x < nelem(globalseg); x++){
g = globalseg[x];
if(g != nil && strcmp(g->name, name) == 0)
break;
}
if(x == nelem(globalseg)){
unlock(&globalseglock);
poperror();
return nil;
}
devpermcheck(g->uid, g->perm, ORDWR);
s = g->s;
if(s == nil)
error("global segment not assigned a virtual address");
if(isoverlap(p, s->base, s->top - s->base) != nil)
error("overlaps existing segment");
incref(s);
unlock(&globalseglock);
poperror();
return s;
}
struct chan *devopen(struct chan *c, int omode, struct dirtab *tab, int ntab,
Devgen * gen)
{
int i;
struct dir dir;
dir.qid.path = 0;
for (i = 0;; i++) {
switch ((*gen) (c, NULL, tab, ntab, i, &dir)) {
case -1:
goto Return;
case 0:
break;
case 1:
if (c->qid.path == dir.qid.path) {
devpermcheck(dir.uid, dir.mode, omode);
goto Return;
}
break;
}
}
Return:
c->offset = 0;
if ((c->qid.type & QTDIR) && !IS_RDONLY(omode))
error("Tried opening dir with non-read-only mode %o", omode);
c->mode = openmode(omode);
c->flag |= COPEN;
return c;
}
Chan*
devopen(Chan *c, int omode, Dirtab *tab, int ntab, Devgen *gen)
{
int i;
Dir dir;
for(i=0;; i++) {
switch((*gen)(c, nil, tab, ntab, i, &dir)){
case -1:
goto Return;
case 0:
break;
case 1:
if(c->qid.path == dir.qid.path) {
devpermcheck(dir.uid, dir.mode, omode);
goto Return;
}
break;
}
}
Return:
c->offset = 0;
if((c->qid.type&QTDIR) && omode!=OREAD)
error(Eperm);
c->mode = openmode(omode);
c->flag |= COPEN;
return c;
}
/*
* if the stream doesn't exist, create it
*/
static struct chan *pipeopen(struct chan *c, int omode)
{
ERRSTACK(2);
Pipe *p;
if (c->qid.type & QTDIR) {
if (omode & O_WRITE)
error(EINVAL, "Can only open directories O_READ, mode is %o oct",
omode);
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
return c;
}
openmode(omode); /* check it */
p = c->aux;
qlock(&p->qlock);
if (waserror()) {
qunlock(&p->qlock);
nexterror();
}
switch (NETTYPE(c->qid.path)) {
case Qdata0:
devpermcheck(p->user, p->pipedir[1].perm, omode);
p->qref[0]++;
break;
case Qdata1:
devpermcheck(p->user, p->pipedir[2].perm, omode);
p->qref[1]++;
break;
}
poperror();
qunlock(&p->qlock);
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
c->iounit = qiomaxatomic;
return c;
}
/*
* if the stream doesn't exist, create it
*/
static Chan*
pipeopen(Chan *c, int omode)
{
Pipe *p;
if(c->qid.type & QTDIR){
if(omode != OREAD)
error(Ebadarg);
c->mode = omode;
c->flag |= COPEN;
c->offset = 0;
return c;
}
openmode(omode); /* check it */
p = c->aux;
qlock(&p->l);
if(waserror()){
qunlock(&p->l);
nexterror();
}
switch(NETTYPE(c->qid.path)){
case Qdata0:
devpermcheck(p->user, p->pipedir[1].perm, omode);
p->qref[0]++;
break;
case Qdata1:
devpermcheck(p->user, p->pipedir[2].perm, omode);
p->qref[1]++;
break;
}
poperror();
qunlock(&p->l);
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
c->iounit = qiomaxatomic;
return c;
}
static Chan*
srvopen(Chan *c, int omode)
{
Srv *sp;
if(c->qid.type == QTDIR){
if(omode & ORCLOSE)
error(Eperm);
if(omode != OREAD)
error(Eisdir);
c->mode = omode;
c->flag |= COPEN;
c->offset = 0;
return c;
}
qlock(&srvlk);
if(waserror()){
qunlock(&srvlk);
nexterror();
}
sp = srvlookup(nil, c->qid.path);
if(sp == 0 || sp->chan == 0)
error(Eshutdown);
if(omode&OTRUNC)
error("srv file already exists");
if(openmode(omode)!=sp->chan->mode && sp->chan->mode!=ORDWR)
error(Eperm);
devpermcheck(sp->owner, sp->perm, omode);
cclose(c);
c = sp->chan;
incref(c);
c->offset = 0;
qunlock(&srvlk);
poperror();
return c;
}
static Chan*
srvopen(Chan *c, int omode)
{
SrvFile *sf;
openmode(omode); /* check it */
if(c->qid.type & QTDIR){
if(omode != OREAD)
error(Eisdir);
c->mode = omode;
c->flag |= COPEN;
c->offset = 0;
return c;
}
sf = c->aux;
qlock(&dev.l);
if(waserror()){
qunlock(&dev.l);
nexterror();
}
devpermcheck(sf->user, sf->perm, omode);
if(omode&ORCLOSE && strcmp(sf->user, up->env->user) != 0)
error(Eperm);
if(sf->perm & DMEXCL && sf->opens != 0)
error(Einuse);
sf->opens++;
if(omode&ORCLOSE)
sf->flags |= SORCLOSE;
poperror();
qunlock(&dev.l);
c->offset = 0;
c->flag |= COPEN;
c->mode = openmode(omode);
return c;
}
static Chan*
progopen(Chan *c, int omode)
{
Prog *p;
Osenv *o;
Progctl *ctl;
int perm;
if(c->qid.type & QTDIR)
return devopen(c, omode, 0, 0, proggen);
acquire();
if (waserror()) {
release();
nexterror();
}
p = progpid(PID(c->qid));
if(p == nil)
error(Ethread);
o = p->osenv;
perm = progdir[QID(c->qid)-1].perm;
if((perm & 7) == 0)
perm = (perm|(perm>>3)|(perm>>6)) & o->pgrp->progmode;
devpermcheck(o->user, perm, omode);
omode = openmode(omode);
switch(QID(c->qid)){
default:
error(Egreg);
case Qnsgrp:
case Qpgrp:
case Qtext:
case Qstatus:
case Qstack:
case Qctl:
case Qfd:
case Qexception:
break;
case Qwait:
c->aux = qopen(1024, Qmsg, nil, nil);
if(c->aux == nil)
error(Enomem);
o->childq = c->aux;
break;
case Qns:
c->aux = malloc(sizeof(Mntwalk));
if(c->aux == nil)
error(Enomem);
break;
case Qheap:
if(SECURE || p->group->flags&Pprivatemem || omode != ORDWR)
error(Eperm);
c->aux = malloc(sizeof(Heapqry));
if(c->aux == nil)
error(Enomem);
break;
case Qdbgctl:
if(SECURE || p->group->flags&Pprivatemem || omode != ORDWR)
error(Eperm);
ctl = malloc(sizeof(Progctl));
if(ctl == nil)
error(Enomem);
ctl->q = qopen(1024, Qmsg, nil, nil);
if(ctl->q == nil) {
free(ctl);
error(Enomem);
}
ctl->bpts = nil;
ctl->ref = 1;
c->aux = ctl;
break;
}
if(p->state != Pexiting)
c->qid.vers = p->pid;
poperror();
release();
c->offset = 0;
c->mode = omode;
c->flag |= COPEN;
return c;
}