ref: 4e34729a89f7c27142566b4b1fd5d51824c83929
dir: /exportfs/exportfs.c/
/*
* exportfs - Export a plan 9 name space across a network
*/
#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <libsec.h>
#include "drawterm.h"
#define Extern
#include "exportfs.h"
/* #define QIDPATH ((1LL<<48)-1) */
#define QIDPATH ((((vlong)1)<<48)-1)
vlong newqid = 0;
void (*fcalls[256])(Fsrpc*);
/* accounting and debugging counters */
int filecnt;
int freecnt;
int qidcnt;
int qfreecnt;
int ncollision;
int netfd;
int
exportfs(int fd)
{
char buf[ERRMAX], ebuf[ERRMAX];
Fsrpc *r;
int i, n;
fcalls[Tversion] = Xversion;
fcalls[Tauth] = Xauth;
fcalls[Tflush] = Xflush;
fcalls[Tattach] = Xattach;
fcalls[Twalk] = Xwalk;
fcalls[Topen] = slave;
fcalls[Tcreate] = Xcreate;
fcalls[Tclunk] = Xclunk;
fcalls[Tread] = slave;
fcalls[Twrite] = slave;
fcalls[Tremove] = Xremove;
fcalls[Tstat] = Xstat;
fcalls[Twstat] = Xwstat;
srvfd = -1;
netfd = fd;
//dbg = 1;
strcpy(buf, "this is buf");
strcpy(ebuf, "this is ebuf");
DEBUG(DFD, "exportfs: started\n");
// rfork(RFNOTEG);
messagesize = iounit(netfd);
if(messagesize == 0)
messagesize = 8192+IOHDRSZ;
Workq = emallocz(sizeof(Fsrpc)*Nr_workbufs);
// for(i=0; i<Nr_workbufs; i++)
// Workq[i].buf = emallocz(messagesize);
fhash = emallocz(sizeof(Fid*)*FHASHSIZE);
fmtinstall('F', fcallfmt);
initroot();
DEBUG(DFD, "exportfs: %s\n", buf);
/*
* Start serving file requests from the network
*/
for(;;) {
r = getsbuf();
if(r == 0)
fatal("Out of service buffers");
DEBUG(DFD, "read9p...");
n = read9pmsg(netfd, r->buf, messagesize);
if(n <= 0)
fatal("eof: n=%d %r", n);
if(convM2S(r->buf, n, &r->work) == 0){
iprint("convM2S %d byte message\n", n);
for(i=0; i<n; i++){
iprint(" %.2ux", r->buf[i]);
if(i%16 == 15)
iprint("\n");
}
if(i%16)
iprint("\n");
fatal("convM2S format error");
}
if(0) iprint("<- %F\n", &r->work);
DEBUG(DFD, "%F\n", &r->work);
(fcalls[r->work.type])(r);
}
}
void
reply(Fcall *r, Fcall *t, char *err)
{
uchar *data;
int m, n;
t->tag = r->tag;
t->fid = r->fid;
if(err) {
t->type = Rerror;
t->ename = err;
}
else
t->type = r->type + 1;
if(0) iprint("-> %F\n", t);
DEBUG(DFD, "\t%F\n", t);
data = malloc(messagesize); /* not mallocz; no need to clear */
if(data == nil)
fatal(Enomem);
n = convS2M(t, data, messagesize);
if((m=write(netfd, data, n))!=n){
iprint("wrote %d got %d (%r)\n", n, m);
fatal("write");
}
free(data);
}
Fid *
getfid(int nr)
{
Fid *f;
for(f = fidhash(nr); f; f = f->next)
if(f->nr == nr)
return f;
return 0;
}
int
freefid(int nr)
{
Fid *f, **l;
char buf[128];
l = &fidhash(nr);
for(f = *l; f; f = f->next) {
if(f->nr == nr) {
if(f->mid) {
sprint(buf, "/mnt/exportfs/%d", f->mid);
unmount(0, buf);
psmap[f->mid] = 0;
}
if(f->f) {
freefile(f->f);
f->f = nil;
}
*l = f->next;
f->next = fidfree;
fidfree = f;
return 1;
}
l = &f->next;
}
return 0;
}
Fid *
newfid(int nr)
{
Fid *new, **l;
int i;
l = &fidhash(nr);
for(new = *l; new; new = new->next)
if(new->nr == nr)
return 0;
if(fidfree == 0) {
fidfree = emallocz(sizeof(Fid) * Fidchunk);
for(i = 0; i < Fidchunk-1; i++)
fidfree[i].next = &fidfree[i+1];
fidfree[Fidchunk-1].next = 0;
}
new = fidfree;
fidfree = new->next;
memset(new, 0, sizeof(Fid));
new->next = *l;
*l = new;
new->nr = nr;
new->fid = -1;
new->mid = 0;
return new;
}
Fsrpc *
getsbuf(void)
{
static int ap;
int look, rounds;
Fsrpc *wb;
int small_instead_of_fast = 1;
if(small_instead_of_fast)
ap = 0; /* so we always start looking at the beginning and reuse buffers */
for(rounds = 0; rounds < 10; rounds++) {
for(look = 0; look < Nr_workbufs; look++) {
if(++ap == Nr_workbufs)
ap = 0;
if(Workq[ap].busy == 0)
break;
}
if(look == Nr_workbufs){
sleep(10 * rounds);
continue;
}
wb = &Workq[ap];
wb->pid = 0;
wb->canint = 0;
wb->flushtag = NOTAG;
wb->busy = 1;
if(wb->buf == nil) /* allocate buffers dynamically to keep size down */
wb->buf = emallocz(messagesize);
return wb;
}
fatal("No more work buffers");
return nil;
}
void
freefile(File *f)
{
File *parent, *child;
Loop:
f->ref--;
if(f->ref > 0)
return;
freecnt++;
if(f->ref < 0) abort();
DEBUG(DFD, "free %s\n", f->name);
/* delete from parent */
parent = f->parent;
if(parent->child == f)
parent->child = f->childlist;
else{
for(child=parent->child; child->childlist!=f; child=child->childlist)
if(child->childlist == nil)
fatal("bad child list");
child->childlist = f->childlist;
}
freeqid(f->qidt);
free(f->name);
f->name = nil;
free(f);
f = parent;
if(f != nil)
goto Loop;
}
File *
file(File *parent, char *name)
{
Dir *dir;
char *path;
File *f;
DEBUG(DFD, "\tfile: 0x%p %s name %s\n", parent, parent->name, name);
path = makepath(parent, name);
dir = dirstat(path);
free(path);
if(dir == nil)
return nil;
for(f = parent->child; f; f = f->childlist)
if(strcmp(name, f->name) == 0)
break;
if(f == nil){
f = emallocz(sizeof(File));
f->name = estrdup(name);
f->parent = parent;
f->childlist = parent->child;
parent->child = f;
parent->ref++;
f->ref = 0;
filecnt++;
}
f->ref++;
f->qid.type = dir->qid.type;
f->qid.vers = dir->qid.vers;
f->qidt = uniqueqid(dir);
f->qid.path = f->qidt->uniqpath;
f->inval = 0;
free(dir);
return f;
}
void
initroot(void)
{
Dir *dir;
root = emallocz(sizeof(File));
root->name = estrdup(".");
dir = dirstat(root->name);
if(dir == nil)
fatal("root stat");
root->ref = 1;
root->qid.vers = dir->qid.vers;
root->qidt = uniqueqid(dir);
root->qid.path = root->qidt->uniqpath;
root->qid.type = QTDIR;
free(dir);
psmpt = emallocz(sizeof(File));
psmpt->name = estrdup("/");
dir = dirstat(psmpt->name);
if(dir == nil)
return;
psmpt->ref = 1;
psmpt->qid.vers = dir->qid.vers;
psmpt->qidt = uniqueqid(dir);
psmpt->qid.path = psmpt->qidt->uniqpath;
free(dir);
psmpt = file(psmpt, "mnt");
if(psmpt == 0)
return;
psmpt = file(psmpt, "exportfs");
}
char*
makepath(File *p, char *name)
{
int i, n;
char *c, *s, *path, *seg[256];
seg[0] = name;
n = strlen(name)+2;
for(i = 1; i < 256 && p; i++, p = p->parent){
seg[i] = p->name;
n += strlen(p->name)+1;
}
path = malloc(n);
if(path == nil)
fatal("out of memory");
s = path;
while(i--) {
for(c = seg[i]; *c; c++)
*s++ = *c;
*s++ = '/';
}
while(s[-1] == '/')
s--;
*s = '\0';
return path;
}
int
qidhash(vlong path)
{
int h, n;
h = 0;
for(n=0; n<64; n+=Nqidbits){
h ^= path;
path >>= Nqidbits;
}
return h & (Nqidtab-1);
}
void
freeqid(Qidtab *q)
{
ulong h;
Qidtab *l;
q->ref--;
if(q->ref > 0)
return;
qfreecnt++;
h = qidhash(q->path);
if(qidtab[h] == q)
qidtab[h] = q->next;
else{
for(l=qidtab[h]; l->next!=q; l=l->next)
if(l->next == nil)
fatal("bad qid list");
l->next = q->next;
}
free(q);
}
Qidtab*
qidlookup(Dir *d)
{
ulong h;
Qidtab *q;
h = qidhash(d->qid.path);
for(q=qidtab[h]; q!=nil; q=q->next)
if(q->type==d->type && q->dev==d->dev && q->path==d->qid.path)
return q;
return nil;
}
int
qidexists(vlong path)
{
int h;
Qidtab *q;
for(h=0; h<Nqidtab; h++)
for(q=qidtab[h]; q!=nil; q=q->next)
if(q->uniqpath == path)
return 1;
return 0;
}
Qidtab*
uniqueqid(Dir *d)
{
ulong h;
vlong path;
Qidtab *q;
q = qidlookup(d);
if(q != nil){
q->ref++;
return q;
}
path = d->qid.path;
while(qidexists(path)){
DEBUG(DFD, "collision on %s\n", d->name);
/* collision: find a new one */
ncollision++;
path &= QIDPATH;
++newqid;
if(newqid >= (1<<16)){
DEBUG(DFD, "collision wraparound\n");
newqid = 1;
}
path |= newqid<<48;
DEBUG(DFD, "assign qid %.16llux\n", path);
}
q = mallocz(sizeof(Qidtab), 1);
if(q == nil)
fatal("no memory for qid table");
qidcnt++;
q->ref = 1;
q->type = d->type;
q->dev = d->dev;
q->path = d->qid.path;
q->uniqpath = path;
h = qidhash(d->qid.path);
q->next = qidtab[h];
qidtab[h] = q;
return q;
}
void
fatal(char *s, ...)
{
char buf[ERRMAX];
va_list arg;
if (s) {
va_start(arg, s);
vsnprint(buf, ERRMAX, s, arg);
va_end(arg);
}
/* Clear away the slave children */
// for(m = Proclist; m; m = m->next)
// postnote(PNPROC, m->pid, "kill");
DEBUG(DFD, "%s\n", buf);
if (s)
sysfatal(buf);
else
sysfatal("");
}