ref: cac03f355caa29a6bd5cafd7d0d6ca362149cb27
parent: 9e363c506eccb783dd4d1d31f14c9d8dba98f65e
author: Jacob Moody <[email protected]>
date: Wed Jun 29 13:35:27 EDT 2022
kernel: revert /srv/clone
--- a/sys/man/3/srv
+++ b/sys/man/3/srv
@@ -5,8 +5,6 @@
.nf
.B bind #s /srv
-.BI #s/ clone
-.BI #s/ n
.BI #s/ service1
.BI #s/ service2
...
@@ -14,7 +12,7 @@
.SH DESCRIPTION
The
.I srv
-device provides a tree of directories holding
+device provides a one-level directory holding
already-open channels to services.
In effect,
.I srv
@@ -42,18 +40,6 @@
.PP
It is an error to write more than one number into a server file,
or to create a file with a name that is already being used.
-.PP
-Opening the
-.I clone
-file allocates a new service directory. Reading
-.I clone
-returns the id of the new directory. This new service
-directory can then be accessed at
-.BR /srv/id .
-Directories are recursable; each new service directory
-contains its own
-.I clone
-file.
.SH EXAMPLE
To drop one end of a pipe into
.BR /srv ,
--- a/sys/src/9/port/devsrv.c
+++ b/sys/src/9/port/devsrv.c
@@ -5,213 +5,61 @@
#include "fns.h"
#include "../port/error.h"
-#include "netif.h"
-typedef struct Link Link;
-struct Link
-{
- void *link;
- char *name;
- ulong path;
-};
-
typedef struct Srv Srv;
struct Srv
{
- Link;
-
+ char *name;
char *owner;
ulong perm;
Chan *chan;
+ Srv *link;
+ ulong path;
};
-typedef struct Board Board;
-struct Board
-{
- Link;
- RWlock;
- Ref;
+static QLock srvlk;
+static Srv *srv;
+static int qidpath;
- Board *parent;
- Board *child;
- Srv *srv;
- long id;
- int qidpath;
- int closed;
-};
-
-struct{
- QLock;
- long path;
-} boards;
-
-enum{
- Qroot,
- Qclone,
- Qlease,
-
- Qend,
-};
-
-Board root;
-
-static char Eexpired[] = "expired lease";
-
-static void*
-lookup(Link *l, char *name, ulong qidpath)
+static Srv*
+srvlookup(char *name, ulong qidpath)
{
- Link *lp;
+ Srv *sp;
- if(qidpath != ~0UL)
- qidpath = NETTYPE(qidpath);
- for(lp = l; lp != nil; lp = lp->link){
- if(qidpath != ~0UL && lp->path == qidpath)
- return lp;
- if(name != nil && strcmp(lp->name, name) == 0)
- return lp;
+ for(sp = srv; sp != nil; sp = sp->link) {
+ if(sp->path == qidpath || (name != nil && strcmp(sp->name, name) == 0))
+ return sp;
}
return nil;
}
-static void*
-remove(Link **l, char *name, ulong qidpath)
-{
- Link *lp;
- Link **last;
-
- if(qidpath != ~0UL)
- qidpath = NETTYPE(qidpath);
- last = l;
- for(lp = *l; lp != nil; lp = lp->link){
- if(qidpath != ~0UL && lp->path == qidpath)
- break;
- if(name != nil && strcmp(lp->name, name) == 0)
- break;
- last = &lp->link;
- }
- if(lp == nil)
- return nil;
-
- *last = lp->link;
- lp->link = nil;
- return lp;
-}
-
-static void
-boardclunk(Board *b, int close)
-{
- Srv *sp, *prv;
- Board *ch;
- long ref;
-
- /* caller holds a wlock */
- if(b == &root){
- wunlock(b);
- return;
- }
-
- if(close){
- assert(b->closed == 0);
- b->closed++;
- for(sp = b->srv; sp != nil; sp = prv){
- prv = sp->link;
- free(sp->owner);
- free(sp->name);
- if(sp->chan != nil)
- cclose(sp->chan);
- free(sp);
- }
- b->srv = nil;
- }
- ref = decref(b);
-
- /*
- * All boards must be walkable from root. So a board
- * is allowed to sit at zero references as long as it
- * still has active children. For leaf nodes we then
- * have to walk up the tree to clear now empty parents.
- */
- while(b->closed && b->child == nil && ref == 0){
- //Root should never be closed
- assert(b->parent != nil);
- wlock(b->parent);
- ch = remove((Link**)&b->parent->child, b->name, b->path);
- assert(ch == b);
-
- b = ch->parent;
- free(ch->name);
- wunlock(ch);
- free(ch);
- }
- wunlock(b);
-}
-
static int
srvgen(Chan *c, char *name, Dirtab*, int, int s, Dir *dp)
{
Srv *sp;
- Board *b, *ch;
Qid q;
- if(name != nil && strlen(name) >= sizeof(up->genbuf))
- return -1;
-
- b = c->aux;
- ch = nil;
- mkqid(&q, ~0L, 0, QTFILE);
- rlock(b);
- if(waserror()){
- runlock(b);
- return -1;
- }
if(s == DEVDOTDOT){
- ch = b->parent;
- if(ch == nil)
- ch = &root;
- goto Child;
-
+ devdir(c, c->qid, "#s", 0, eve, 0555, dp);
+ return 1;
}
- if(name != nil){
- if(strcmp("clone", name) == 0)
- goto Clone;
- sp = lookup(b->srv, name, ~0UL);
- if(sp == nil)
- ch = lookup(b->child, name, ~0UL);
- } else {
- if(s == 0)
- goto Clone;
- s--;
- for(sp = b->srv; sp != nil && s > 0; sp = sp->link)
+ qlock(&srvlk);
+ if(name != nil)
+ sp = srvlookup(name, -1);
+ else {
+ for(sp = srv; sp != nil && s > 0; sp = sp->link)
s--;
- for(ch = b->child; ch != nil && s > 0; ch = ch->link)
- s--;
}
- if(sp != nil){
- kstrcpy(up->genbuf, sp->name, sizeof up->genbuf);
- q.vers = NETID(c->qid.path);
- q.path = NETQID(q.vers, sp->path);
- devdir(c, q, up->genbuf, 0, sp->owner, sp->perm, dp);
- } else if(ch != nil){
-Child:
- kstrcpy(up->genbuf, ch->name, sizeof up->genbuf);
- q.vers = ch->id;
- q.path = NETQID(q.vers, ch->path);
- q.type = QTDIR;
- devdir(c, q, up->genbuf, 0, eve, 0555|DMDIR, dp);
- /* dirread's and stats shouldn't alter c->aux */
- if(name != nil)
- c->aux = ch;
- } else if(0){
-Clone:
- q.vers = NETID(c->qid.path);
- q.path = NETQID(q.vers, Qclone);
- devdir(c, q, "clone", 0, eve, 0444, dp);
- } else
- error(Enonexist);
-
- runlock(b);
- poperror();
+ 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;
}
@@ -218,36 +66,19 @@
static void
srvinit(void)
{
- root.qidpath = Qend;
- root.name = "#s";
+ qidpath = 1;
}
static Chan*
srvattach(char *spec)
{
- Chan *c;
-
- c = devattach('s', spec);
- c->aux = &root;
- return c;
+ return devattach('s', spec);
}
static Walkqid*
srvwalk(Chan *c, Chan *nc, char **name, int nname)
{
- Board *b;
- Walkqid *wq;
-
- wq = devwalk(c, nc, name, nname, 0, 0, srvgen);
- if(wq == nil || wq->clone == nil)
- return wq;
-
- b = wq->clone->aux;
- if(b == &root)
- return wq;
-
- incref(b);
- return wq;
+ return devwalk(c, nc, name, nname, 0, 0, srvgen);
}
static int
@@ -259,14 +90,12 @@
char*
srvname(Chan *c)
{
- Board *b;
Srv *sp;
char *s;
s = nil;
- b = &root;
- rlock(b);
- for(sp = b->srv; sp != nil; sp = sp->link) {
+ qlock(&srvlk);
+ for(sp = srv; sp != nil; sp = sp->link) {
if(sp->chan == c){
s = malloc(3+strlen(sp->name)+1);
if(s != nil)
@@ -274,7 +103,7 @@
break;
}
}
- runlock(b);
+ qunlock(&srvlk);
return s;
}
@@ -281,10 +110,8 @@
static Chan*
srvopen(Chan *c, int omode)
{
- Board *b, *ch;
Srv *sp;
Chan *nc;
- char buf[64];
if(c->qid.type == QTDIR){
if(omode & ORCLOSE)
@@ -296,53 +123,20 @@
c->offset = 0;
return c;
}
- if(omode&OTRUNC)
- error(Eexist);
- if(omode&ORCLOSE)
- error(Eperm);
-
- b = c->aux;
- if(NETTYPE(c->qid.path) == Qclone){;
- wlock(b);
- if(b->closed){
- wunlock(b);
- error(Eexpired);
- }
- ch = smalloc(sizeof *ch);
- ch->qidpath = Qend;
- ch->ref = 1;
- do {
- qlock(&boards);
- ch->id = ++boards.path;
- qunlock(&boards);
- snprint(buf, sizeof buf, "%ld", ch->id);
- } while(lookup(b->srv, buf, ~0UL) != nil);
-
- ch->parent = b;
- ch->path = b->qidpath++;
- kstrdup(&ch->name, buf);
-
- ch->link = b->child;
- b->child = ch;
- c->aux = ch;
- c->qid.vers = ch->id;
- c->qid.path = NETQID(ch->id, Qlease);
- boardclunk(b, 0); //unlock
- return c;
- }
-
- rlock(b);
+ qlock(&srvlk);
if(waserror()){
- runlock(b);
+ qunlock(&srvlk);
nexterror();
}
- if(b->closed)
- error(Eexpired);
- sp = lookup(b->srv, nil, c->qid.path);
+ sp = srvlookup(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);
@@ -350,7 +144,7 @@
nc = sp->chan;
incref(nc);
- runlock(b);
+ qunlock(&srvlk);
poperror();
cclose(c);
@@ -360,7 +154,6 @@
static Chan*
srvcreate(Chan *c, char *name, int omode, ulong perm)
{
- Board *b;
Srv *sp;
if(openmode(omode) != OWRITE)
@@ -373,33 +166,27 @@
kstrdup(&sp->name, name);
kstrdup(&sp->owner, up->user);
- b = c->aux;
- wlock(b);
+ qlock(&srvlk);
if(waserror()){
- wunlock(b);
+ qunlock(&srvlk);
free(sp->owner);
free(sp->name);
free(sp);
nexterror();
}
- if(b->closed)
- error(Eexpired);
- if(lookup(b->srv, name, ~0UL) != nil)
+ if(srvlookup(name, -1) != nil)
error(Eexist);
- if(lookup(b->child, name, ~0UL) != nil)
- error(Eexist);
sp->perm = perm&0777;
- sp->path = b->qidpath++;
+ sp->path = qidpath++;
- c->qid.path = NETQID(b->id, sp->path);
- c->qid.vers = b->id;
+ c->qid.path = sp->path;
c->qid.type = QTFILE;
- sp->link = b->srv;
- b->srv = sp;
+ sp->link = srv;
+ srv = sp;
- wunlock(b);
+ qunlock(&srvlk);
poperror();
c->flag |= COPEN;
@@ -411,24 +198,22 @@
static void
srvremove(Chan *c)
{
- Board *b;
- Srv *sp;
+ Srv *sp, **l;
if(c->qid.type == QTDIR)
error(Eperm);
- switch(NETTYPE(c->qid.path)){
- case Qlease:
- case Qclone:
- error(Eperm);
- }
- b = c->aux;
- wlock(b);
+ qlock(&srvlk);
if(waserror()){
- wunlock(b);
+ qunlock(&srvlk);
nexterror();
}
- sp = lookup(b->srv, nil, c->qid.path);
+ l = &srv;
+ for(sp = *l; sp != nil; sp = *l) {
+ if(sp->path == c->qid.path)
+ break;
+ l = &sp->link;
+ }
if(sp == nil)
error(Enonexist);
@@ -444,9 +229,10 @@
if((sp->perm&7) != 7 && strcmp(sp->owner, up->user) && !iseve())
error(Eperm);
- remove((Link**)&b->srv, nil, c->qid.path);
+ *l = sp->link;
+ sp->link = nil;
- boardclunk(b, 0); //unlock
+ qunlock(&srvlk);
poperror();
if(sp->chan != nil)
@@ -459,7 +245,6 @@
static int
srvwstat(Chan *c, uchar *dp, int n)
{
- Board *b;
char *strs;
Srv *sp;
Dir d;
@@ -466,11 +251,6 @@
if(c->qid.type & QTDIR)
error(Eperm);
- switch(NETTYPE(c->qid.path)){
- case Qlease:
- case Qclone:
- error(Eperm);
- }
strs = smalloc(n);
if(waserror()){
@@ -481,16 +261,13 @@
if(n == 0)
error(Eshortstat);
- b = c->aux;
- wlock(b);
+ qlock(&srvlk);
if(waserror()){
- wunlock(b);
+ qunlock(&srvlk);
nexterror();
}
- if(b->closed)
- error(Eexpired);
- sp = lookup(b->srv, nil, c->qid.path);
+ sp = srvlookup(nil, c->qid.path);
if(sp == nil)
error(Enonexist);
@@ -502,10 +279,6 @@
error(Ebadchar);
if(strlen(d.name) >= sizeof(up->genbuf))
error(Etoolong);
- if(lookup(b->srv, d.name, ~0UL) != nil)
- error(Eexist);
- if(lookup(b->child, d.name, ~0UL) != nil)
- error(Eexist);
kstrdup(&sp->name, d.name);
}
if(d.uid != nil && *d.uid)
@@ -513,7 +286,7 @@
if(d.mode != ~0UL)
sp->perm = d.mode & 0777;
- wunlock(b);
+ qunlock(&srvlk);
poperror();
free(strs);
@@ -525,47 +298,22 @@
static void
srvclose(Chan *c)
{
- Board *b;
- int expired;
-
- expired = 0;
- if(NETTYPE(c->qid.path) == Qlease)
- expired++;
- else if(c->flag & CRCLOSE){
- /*
- * 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.
- */
+ /*
+ * 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())
- goto Clunk;
+ return;
srvremove(c);
poperror();
- return;
}
-Clunk:
- b = c->aux;
- wlock(b);
- boardclunk(b, expired); //unlock
}
static long
-srvread(Chan *c, void *va, long n, vlong off)
+srvread(Chan *c, void *va, long n, vlong)
{
- Board *b;
-
- if(NETTYPE(c->qid.path) == Qlease){
- b = c->aux;
- rlock(b);
- if(waserror()){
- runlock(b);
- nexterror();
- }
- n = readstr((ulong)off, va, n, b->name);
- runlock(b);
- poperror();
- return n;
- }
isdir(c);
return devdirread(c, va, n, 0, 0, srvgen);
}
@@ -573,15 +321,11 @@
static long
srvwrite(Chan *c, void *va, long n, vlong)
{
- Board *b;
Srv *sp;
Chan *c1;
int fd;
char buf[32];
- if(NETTYPE(c->qid.path) == Qlease)
- error(Eperm);
-
if(n >= sizeof buf)
error(Etoobig);
memmove(buf, va, n); /* so we can NUL-terminate */
@@ -590,18 +334,15 @@
c1 = fdtochan(fd, -1, 0, 1); /* error check and inc ref */
- b = c->aux;
- wlock(b);
+ qlock(&srvlk);
if(waserror()) {
- wunlock(b);
+ qunlock(&srvlk);
cclose(c1);
nexterror();
}
- if(b->closed)
- error(Eexpired);
if(c1->qid.type & QTAUTH)
error("cannot post auth file in srv");
- sp = lookup(b->srv, nil, c->qid.path);
+ sp = srvlookup(nil, c->qid.path);
if(sp == nil)
error(Enonexist);
@@ -610,7 +351,7 @@
sp->chan = c1;
- wunlock(b);
+ qunlock(&srvlk);
poperror();
return n;
}
@@ -639,14 +380,12 @@
void
srvrenameuser(char *old, char *new)
{
- Board *b;
Srv *sp;
- b = &root;
- wlock(b);
- for(sp = b->srv; sp != nil; sp = sp->link) {
+ qlock(&srvlk);
+ for(sp = srv; sp != nil; sp = sp->link) {
if(sp->owner != nil && strcmp(old, sp->owner) == 0)
kstrdup(&sp->owner, new);
}
- wunlock(b);
+ qunlock(&srvlk);
}