ref: 68f15d65942da7e30cf9cbae7362f778fe5da1d2
dir: /sys/src/cmd/execnet/fs.c/
/*
* ``Exec'' network device. Mounted on net, provides /net/exec.
*
* exec protocol directory
* n connection directory
* ctl control messages (like connect)
* data data
* err errors
* local local address (pid of command)
* remote remote address (command)
* status status
*/
#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
#include "dat.h"
int fsdebug;
enum
{
Qroot,
Qexec,
Qclone,
Qn,
Qctl,
Qdata,
Qlocal,
Qremote,
Qstatus,
};
#define PATH(type, n) ((type)|((n)<<8))
#define TYPE(path) ((int)(path) & 0xFF)
#define NUM(path) ((uint)(path)>>8)
typedef struct Tab Tab;
struct Tab
{
char *name;
ulong mode;
};
Tab tab[] =
{
"/", DMDIR|0555,
"exec", DMDIR|0555,
"clone", 0666,
nil, DMDIR|0555,
"ctl", 0666,
"data", 0666,
"local", 0444,
"remote", 0444,
"status", 0444,
};
void
setexecname(char *s)
{
tab[Qexec].name = s;
}
ulong time0;
static void
fillstat(Dir *d, ulong path)
{
Tab *t;
int type;
char buf[32];
memset(d, 0, sizeof(*d));
d->uid = estrdup("exec");
d->gid = estrdup("exec");
d->qid.path = path;
d->atime = d->mtime = time0;
d->length = 0;
type = TYPE(path);
t = &tab[type];
if(t->name)
d->name = estrdup(t->name);
else{
snprint(buf, sizeof buf, "%ud", NUM(path));
d->name = estrdup(buf);
}
d->qid.type = t->mode>>24;
d->mode = t->mode;
}
static void
fsstat(Req *r)
{
fillstat(&r->d, r->fid->qid.path);
respond(r, nil);
}
static int
rootgen(int i, Dir *d, void*)
{
if(i < 1){
fillstat(d, PATH(Qexec, 0));
return 0;
}
return -1;
}
static int
execgen(int i, Dir *d, void*)
{
if(i < 1){
fillstat(d, PATH(Qclone, 0));
return 0;
}
i -= 1;
if(i < nclient){
fillstat(d, PATH(Qn, i));
return 0;
}
return -1;
}
static int
conngen(int i, Dir *d, void *aux)
{
Client *c;
c = aux;
i += Qn+1;
if(i <= Qstatus){
fillstat(d, PATH(i, c->num));
return 0;
}
return -1;
}
char *statusstr[] =
{
"Closed",
"Exec",
"Established",
"Hangup",
};
static void
fsread(Req *r)
{
char e[ERRMAX], *s;
ulong path;
path = r->fid->qid.path;
switch(TYPE(path)){
default:
snprint(e, sizeof e, "bug in execnet path=%lux", path);
respond(r, e);
break;
case Qroot:
dirread9p(r, rootgen, nil);
respond(r, nil);
break;
case Qexec:
dirread9p(r, execgen, nil);
respond(r, nil);
break;
case Qn:
dirread9p(r, conngen, client[NUM(path)]);
respond(r, nil);
break;
case Qctl:
snprint(e, sizeof e, "%ud", NUM(path));
readstr(r, e);
respond(r, nil);
break;
case Qdata:
dataread(r, client[NUM(path)]);
break;
case Qlocal:
snprint(e, sizeof e, "%d", client[NUM(path)]->pid);
readstr(r, e);
respond(r, nil);
break;
case Qremote:
s = client[NUM(path)]->cmd;
if(strlen(s) >= 5) /* "exec " */
readstr(r, s+5);
else
readstr(r, s);
respond(r, nil);
break;
case Qstatus:
readstr(r, statusstr[client[NUM(path)]->status]);
respond(r, nil);
break;
}
}
static void
fswrite(Req *r)
{
char e[ERRMAX];
ulong path;
path = r->fid->qid.path;
switch(TYPE(path)){
default:
snprint(e, sizeof e, "bug in execnet path=%lux", path);
respond(r, e);
break;
case Qctl:
ctlwrite(r, client[NUM(path)]);
break;
case Qdata:
datawrite(r, client[NUM(path)]);
break;
}
}
static void
fsflush(Req *r)
{
ulong path;
Req *or;
for(or=r; or->ifcall.type==Tflush; or=or->oldreq)
;
if(or->ifcall.type != Tread && or->ifcall.type != Twrite)
abort();
path = or->fid->qid.path;
if(TYPE(path) != Qdata)
abort();
clientflush(or, client[NUM(path)]);
respond(r, nil);
}
static void
fsattach(Req *r)
{
if(r->ifcall.aname && r->ifcall.aname[0]){
respond(r, "invalid attach specifier");
return;
}
r->fid->qid.path = PATH(Qroot, 0);
r->fid->qid.type = QTDIR;
r->fid->qid.vers = 0;
r->ofcall.qid = r->fid->qid;
respond(r, nil);
}
static char*
fswalk1(Fid *fid, char *name, Qid *qid)
{
char buf[32];
int i, n;
ulong path;
if(!(fid->qid.type&QTDIR))
return "walk in non-directory";
path = fid->qid.path;
if(strcmp(name, "..") == 0){
switch(TYPE(path)){
case Qn:
qid->path = PATH(Qexec, 0);
qid->type = QTDIR;
return nil;
case Qroot:
case Qexec:
qid->path = PATH(Qroot, 0);
qid->type = QTDIR;
return nil;
default:
return "bug in fswalk1";
}
}
i = TYPE(path)+1;
for(; i<nelem(tab); i++){
if(i==Qn){
n = atoi(name);
snprint(buf, sizeof buf, "%d", n);
if(n < nclient && strcmp(buf, name) == 0){
qid->path = PATH(Qn, n);
qid->type = QTDIR;
return nil;
}
break;
}
if(strcmp(tab[i].name, name) == 0){
qid->path = PATH(i, NUM(path));
qid->type = tab[i].mode>>24;
return nil;
}
if(tab[i].mode&DMDIR)
break;
}
return "directory entry not found";
}
static void
fsopen(Req *r)
{
static int need[4] = { 4, 2, 6, 1 };
ulong path;
int n;
Tab *t;
/*
* lib9p already handles the blatantly obvious.
* we just have to enforce the permissions we have set.
*/
path = r->fid->qid.path;
t = &tab[TYPE(path)];
n = need[r->ifcall.mode&3];
if((n&t->mode) != n){
respond(r, "permission denied");
return;
}
switch(TYPE(path)){
case Qclone:
n = newclient();
path = PATH(Qctl, n);
r->fid->qid.path = path;
r->ofcall.qid.path = path;
if(fsdebug)
fprint(2, "open clone => path=%lux\n", path);
t = &tab[Qctl];
/* fall through */
default:
if(t-tab >= Qn)
client[NUM(path)]->ref++;
respond(r, nil);
break;
}
}
Channel *cclunk;
Channel *cclunkwait;
Channel *creq;
Channel *creqwait;
static void
fsthread(void*)
{
ulong path;
Alt a[3];
Fid *fid;
Req *r;
threadsetname("fsthread");
a[0].op = CHANRCV;
a[0].c = cclunk;
a[0].v = &fid;
a[1].op = CHANRCV;
a[1].c = creq;
a[1].v = &r;
a[2].op = CHANEND;
for(;;){
switch(alt(a)){
case 0:
path = fid->qid.path;
if(fid->omode != -1 && TYPE(path) >= Qn)
closeclient(client[NUM(path)]);
sendp(cclunkwait, nil);
break;
case 1:
switch(r->ifcall.type){
case Tattach:
fsattach(r);
break;
case Topen:
fsopen(r);
break;
case Tread:
fsread(r);
break;
case Twrite:
fswrite(r);
break;
case Tstat:
fsstat(r);
break;
case Tflush:
fsflush(r);
break;
default:
respond(r, "bug in fsthread");
break;
}
sendp(creqwait, 0);
break;
}
}
}
static void
fsdestroyfid(Fid *fid)
{
sendp(cclunk, fid);
recvp(cclunkwait);
}
static void
fssend(Req *r)
{
sendp(creq, r);
recvp(creqwait); /* avoids need to deal with spurious flushes */
}
void
initfs(void)
{
time0 = time(0);
creq = chancreate(sizeof(void*), 0);
creqwait = chancreate(sizeof(void*), 0);
cclunk = chancreate(sizeof(void*), 0);
cclunkwait = chancreate(sizeof(void*), 0);
procrfork(fsthread, nil, STACK, RFNAMEG);
}
Srv fs =
{
.attach= fssend,
.destroyfid= fsdestroyfid,
.walk1= fswalk1,
.open= fssend,
.read= fssend,
.write= fssend,
.stat= fssend,
.flush= fssend,
};