ref: c3e1346bbcc2f737ff69fdc353125714ec937ddb
dir: /sys/src/9/port/devsrv.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "netif.h"
typedef struct Srv Srv;
struct Srv
{
char *name;
char *owner;
ulong perm;
Chan *chan;
Srv *link;
ulong path;
};
typedef struct Fid Fid;
struct Fid
{
int ref;
QLock lk;
Srv *tail;
ulong nextpath;
};
enum{
Qroot,
Qclone,
Qend
};
static Fid global;
struct {
QLock;
ulong path;
} sessions;
static Srv*
srvlookup(Srv *sp, char *name, ulong qidpath)
{
qidpath = NETTYPE(qidpath);
for(; sp != nil; sp = sp->link) {
if(sp->path == qidpath || (name != nil && strcmp(sp->name, name) == 0))
return sp;
}
return nil;
}
static int
srvgen(Chan *c, char *name, Dirtab*, int, int s, Dir *dp)
{
Srv *sp;
Qid q;
Fid *f;
ulong id;
if(s == DEVDOTDOT){
switch(NETTYPE(c->qid.path)){
case Qroot:
mkqid(&q, Qroot, 0, QTDIR);
devdir(c, q, "#s", 0, eve, 0555|DMDIR, dp);
break;
case Qclone:
default:
/*
* Someone has walked down /srv/clone/clone/.... and
* would like back up. We do not allow revisiting
* previous sessions. Dead end
*/
error(Enonexist);
break;
}
return 1;
}
id = NETID(c->qid.path);
if(name != nil && strcmp(name, "clone") == 0){
/* walk; new session */
qlock(&sessions);
id = ++sessions.path;
qunlock(&sessions);
f = smalloc(sizeof *f);
f->ref = 1;
f->nextpath = Qend;
mkqid(&q, NETQID(id, Qclone), id, QTDIR);
devdir(c, q, "clone", 0, eve, 0555|DMDIR, dp);
c->aux = f;
return 1;
} else if(name == nil && s == 0) {
/* stat, dirread; current session */
mkqid(&q, NETQID(id, Qclone), id, QTDIR);
devdir(c, q, "clone", 0, eve, 0555|DMDIR, dp);
return 1;
}
f = c->aux;
qlock(&f->lk);
if(name != nil)
sp = srvlookup(f->tail, name, -1);
else {
s -= 1;
for(sp = f->tail; sp != nil && s > 0; sp = sp->link)
s--;
}
if(sp == nil || (name != nil && (strlen(sp->name) >= sizeof(up->genbuf)))) {
qunlock(&f->lk);
return -1;
}
mkqid(&q, NETQID(id, sp->path), 0, QTFILE);
/* make sure name string continues to exist after we release lock */
kstrcpy(up->genbuf, sp->name, sizeof up->genbuf);
devdir(c, q, up->genbuf, 0, sp->owner, sp->perm, dp);
qunlock(&f->lk);
return 1;
}
static void
srvinit(void)
{
global.nextpath = Qend;
}
static Chan*
srvattach(char *spec)
{
Chan *c;
c = devattach('s', spec);
c->aux = &global;
return c;
}
static Walkqid*
srvwalk(Chan *c, Chan *nc, char **name, int nname)
{
Walkqid *wq;
Fid *f;
int tripped;
/*
* We need to allow for infinite recursions through clone but we
* don't need to permit passing multiple clones in a single walk.
* This allows us to ensure that only a single clone is alloted
* per walk.
*/
tripped = 0;
if(nname > 1){
nname = 1;
tripped = 1;
}
wq = devwalk(c, nc, name, nname, 0, 0, srvgen);
if(wq == nil || wq->clone == nil || wq->clone == c)
return wq;
if(tripped){
/*
* Our partial walk returned a newly alloc'd clone.
* We wll never see a clunk for that partially walked
* fid, so just clean it up now.
*/
if(NETTYPE(wq->clone->qid.path) == Qclone){
f = wq->clone->aux;
assert(f->tail == nil);
assert(f->ref == 1);
free(f);
}
/* Correct state to indicate failure to walk all names */
wq->clone->type = 0;
cclose(wq->clone);
wq->clone = nil;
return wq;
}
if(wq->clone->aux == &global)
return wq;
if(NETID(c->qid.path) != NETID(wq->clone->qid.path))
return wq;
assert(c->aux == wq->clone->aux);
f = c->aux;
qlock(&f->lk);
f->ref++;
qunlock(&f->lk);
return wq;
}
static int
srvstat(Chan *c, uchar *db, int n)
{
return devstat(c, db, n, 0, 0, srvgen);
}
char*
srvname(Chan *c)
{
Srv *sp;
Fid *f;
char *s;
s = nil;
f = &global;
qlock(&f->lk);
for(sp = f->tail; sp != nil; sp = sp->link) {
if(sp->chan == c){
s = malloc(3+strlen(sp->name)+1);
if(s != nil)
sprint(s, "#s/%s", sp->name);
break;
}
}
qunlock(&f->lk);
return s;
}
static Chan*
srvopen(Chan *c, int omode)
{
Srv *sp;
Fid *f;
Chan *nc;
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;
}
f = c->aux;
qlock(&f->lk);
if(waserror()){
qunlock(&f->lk);
nexterror();
}
sp = srvlookup(f->tail, nil, c->qid.path);
if(sp == nil || sp->chan == nil)
error(Eshutdown);
if(omode&OTRUNC)
error(Eexist);
if(omode&ORCLOSE)
error(Eperm);
if(openmode(omode)!=sp->chan->mode && sp->chan->mode!=ORDWR)
error(Eperm);
devpermcheck(sp->owner, sp->perm, omode);
nc = sp->chan;
incref(nc);
qunlock(&f->lk);
poperror();
cclose(c);
return nc;
}
static Chan*
srvcreate(Chan *c, char *name, int omode, ulong perm)
{
Srv *sp;
Fid *f;
if(openmode(omode) != OWRITE)
error(Eperm);
if(strlen(name) >= sizeof(up->genbuf))
error(Etoolong);
f = c->aux;
sp = smalloc(sizeof *sp);
kstrdup(&sp->name, name);
kstrdup(&sp->owner, up->user);
qlock(&f->lk);
if(waserror()){
qunlock(&f->lk);
free(sp->owner);
free(sp->name);
free(sp);
nexterror();
}
if(srvlookup(f->tail, name, -1) != nil)
error(Eexist);
sp->perm = perm&0777;
sp->path = f->nextpath++;
c->qid.path = NETQID(NETID(c->qid.path), sp->path);
c->qid.type = QTFILE;
sp->link = f->tail;
f->tail = sp;
qunlock(&f->lk);
poperror();
c->flag |= COPEN;
c->mode = OWRITE;
return c;
}
static void
srvremove(Chan *c)
{
Srv *sp, **l;
Fid *f;
ulong id;
if(c->qid.type == QTDIR)
error(Eperm);
f = c->aux;
qlock(&f->lk);
if(waserror()){
qunlock(&f->lk);
nexterror();
}
l = &f->tail;
for(sp = *l; sp != nil; sp = *l) {
if(sp->path == NETTYPE(c->qid.path))
break;
l = &sp->link;
}
if(sp == nil)
error(Enonexist);
/*
* Only eve can remove system services.
*/
if(strcmp(sp->owner, eve) == 0 && !iseve())
error(Eperm);
/*
* No removing personal services.
*/
if((sp->perm&7) != 7 && strcmp(sp->owner, up->user) && !iseve())
error(Eperm);
*l = sp->link;
sp->link = nil;
id = NETID(c->qid.path);
poperror();
if(sp->chan != nil)
cclose(sp->chan);
free(sp->owner);
free(sp->name);
free(sp);
if(f == &global){
qunlock(&f->lk);
return;
}
f->ref--;
if(f->ref == 0){
assert(f->tail == nil);
qunlock(&f->lk);
free(f);
} else if(f->ref < 0)
panic("srv ref rm %d id %uld", f->ref, id);
else
qunlock(&f->lk);
}
static int
srvwstat(Chan *c, uchar *dp, int n)
{
char *strs;
Srv *sp;
Fid *f;
Dir d;
if(c->qid.type & QTDIR)
error(Eperm);
strs = smalloc(n);
if(waserror()){
free(strs);
nexterror();
}
n = convM2D(dp, n, &d, strs);
if(n == 0)
error(Eshortstat);
f = c->aux;
qlock(&f->lk);
if(waserror()){
qunlock(&f->lk);
nexterror();
}
sp = srvlookup(f->tail, nil, c->qid.path);
if(sp == nil)
error(Enonexist);
if(strcmp(sp->owner, up->user) != 0 && !iseve())
error(Eperm);
if(d.name != nil && *d.name && strcmp(sp->name, d.name) != 0) {
if(strchr(d.name, '/') != nil)
error(Ebadchar);
if(strlen(d.name) >= sizeof(up->genbuf))
error(Etoolong);
kstrdup(&sp->name, d.name);
}
if(d.uid != nil && *d.uid)
kstrdup(&sp->owner, d.uid);
if(d.mode != ~0UL)
sp->perm = d.mode & 0777;
qunlock(&f->lk);
poperror();
free(strs);
poperror();
return n;
}
static void
srvclose(Chan *c)
{
Fid *f;
/*
* in theory we need to override any changes in removability
* since open, but since all that's checked is the owner,
* which is immutable, all is well.
*/
if((c->flag & COPEN) && (c->flag & CRCLOSE)){
if(waserror())
goto ref;
srvremove(c);
poperror();
} else {
ref:
f = c->aux;
if(f == &global)
return;
qlock(&f->lk);
f->ref--;
if(f->ref == 0){
assert(f->tail == nil);
qunlock(&f->lk);
free(f);
} else if(f->ref < 0)
panic("srvref close %d %uld", f->ref, NETID(c->qid.path));
else
qunlock(&f->lk);
}
}
static long
srvread(Chan *c, void *va, long n, vlong)
{
isdir(c);
return devdirread(c, va, n, 0, 0, srvgen);
}
static long
srvwrite(Chan *c, void *va, long n, vlong)
{
Srv *sp;
Fid *f;
Chan *c1;
int fd;
char buf[32];
if(n >= sizeof buf)
error(Etoobig);
memmove(buf, va, n); /* so we can NUL-terminate */
buf[n] = 0;
fd = strtoul(buf, 0, 0);
c1 = fdtochan(fd, -1, 0, 1); /* error check and inc ref */
f = c->aux;
qlock(&f->lk);
if(waserror()) {
qunlock(&f->lk);
cclose(c1);
nexterror();
}
if(c1->qid.type & QTAUTH)
error("cannot post auth file in srv");
sp = srvlookup(f->tail, nil, c->qid.path);
if(sp == nil)
error(Enonexist);
if(sp->chan != nil)
error(Ebadusefd);
sp->chan = c1;
qunlock(&f->lk);
poperror();
return n;
}
Dev srvdevtab = {
's',
"srv",
devreset,
srvinit,
devshutdown,
srvattach,
srvwalk,
srvstat,
srvopen,
srvcreate,
srvclose,
srvread,
devbread,
srvwrite,
devbwrite,
srvremove,
srvwstat,
};
void
srvrenameuser(char *old, char *new)
{
Srv *sp;
Fid *f;
f = &global;
qlock(&f->lk);
for(sp = f->tail; sp != nil; sp = sp->link) {
if(sp->owner != nil && strcmp(old, sp->owner) == 0)
kstrdup(&sp->owner, new);
}
qunlock(&f->lk);
}