ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
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"
typedef struct Srv Srv;
struct Srv
{
char *name;
char *owner;
ulong perm;
Chan *chan;
Srv *link;
ulong path;
};
static QLock srvlk;
static Srv *srv;
static int qidpath;
static Srv*
srvlookup(char *name, ulong qidpath)
{
Srv *sp;
for(sp = srv; 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;
if(s == DEVDOTDOT){
devdir(c, c->qid, "#s", 0, eve, 0555, dp);
return 1;
}
qlock(&srvlk);
if(name != nil)
sp = srvlookup(name, -1);
else {
for(sp = srv; sp != nil && s > 0; sp = sp->link)
s--;
}
if(sp == nil || (name != nil && (strlen(sp->name) >= sizeof(up->genbuf)))) {
qunlock(&srvlk);
return -1;
}
mkqid(&q, 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(&srvlk);
return 1;
}
static void
srvinit(void)
{
qidpath = 1;
}
static Chan*
srvattach(char *spec)
{
return devattach('s', spec);
}
static Walkqid*
srvwalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, 0, 0, srvgen);
}
static int
srvstat(Chan *c, uchar *db, int n)
{
return devstat(c, db, n, 0, 0, srvgen);
}
char*
srvname(Chan *c)
{
Srv *sp;
char *s;
s = nil;
qlock(&srvlk);
for(sp = srv; 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(&srvlk);
return s;
}
static Chan*
srvopen(Chan *c, int omode)
{
Srv *sp;
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;
}
qlock(&srvlk);
if(waserror()){
qunlock(&srvlk);
nexterror();
}
sp = srvlookup(nil, c->qid.path);
if(sp == nil || sp->chan == nil)
error(Eshutdown);
if(omode&OTRUNC)
error(Eexist);
if(openmode(omode)!=sp->chan->mode && sp->chan->mode!=ORDWR)
error(Eperm);
devpermcheck(sp->owner, sp->perm, omode);
nc = sp->chan;
incref(nc);
qunlock(&srvlk);
poperror();
cclose(c);
return nc;
}
static Chan*
srvcreate(Chan *c, char *name, int omode, ulong perm)
{
Srv *sp;
if(openmode(omode) != OWRITE)
error(Eperm);
if(strlen(name) >= sizeof(up->genbuf))
error(Etoolong);
sp = smalloc(sizeof *sp);
kstrdup(&sp->name, name);
kstrdup(&sp->owner, up->user);
qlock(&srvlk);
if(waserror()){
qunlock(&srvlk);
free(sp->owner);
free(sp->name);
free(sp);
nexterror();
}
if(srvlookup(name, -1) != nil)
error(Eexist);
sp->perm = perm&0777;
sp->path = qidpath++;
c->qid.path = sp->path;
c->qid.type = QTFILE;
sp->link = srv;
srv = sp;
qunlock(&srvlk);
poperror();
c->flag |= COPEN;
c->mode = OWRITE;
return c;
}
static void
srvremove(Chan *c)
{
Srv *sp, **l;
if(c->qid.type == QTDIR)
error(Eperm);
qlock(&srvlk);
if(waserror()){
qunlock(&srvlk);
nexterror();
}
l = &srv;
for(sp = *l; sp != nil; sp = *l) {
if(sp->path == 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;
qunlock(&srvlk);
poperror();
if(sp->chan != nil)
cclose(sp->chan);
free(sp->owner);
free(sp->name);
free(sp);
}
static int
srvwstat(Chan *c, uchar *dp, int n)
{
char *strs;
Srv *sp;
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);
qlock(&srvlk);
if(waserror()){
qunlock(&srvlk);
nexterror();
}
sp = srvlookup(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(&srvlk);
poperror();
free(strs);
poperror();
return n;
}
static void
srvclose(Chan *c)
{
/*
* 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 & CRCLOSE){
if(waserror())
return;
srvremove(c);
poperror();
}
}
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;
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 */
qlock(&srvlk);
if(waserror()) {
qunlock(&srvlk);
cclose(c1);
nexterror();
}
if(c1->flag & (CCEXEC|CRCLOSE))
error("posted fd has remove-on-close or close-on-exec");
if(c1->qid.type & QTAUTH)
error("cannot post auth file in srv");
sp = srvlookup(nil, c->qid.path);
if(sp == nil)
error(Enonexist);
if(sp->chan != nil)
error(Ebadusefd);
sp->chan = c1;
qunlock(&srvlk);
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;
qlock(&srvlk);
for(sp = srv; sp != nil; sp = sp->link) {
if(sp->owner != nil && strcmp(old, sp->owner) == 0)
kstrdup(&sp->owner, new);
}
qunlock(&srvlk);
}