ref: a7081490dbeda19788e6374a080ee38606aa3cd3
dir: /sys/src/cmd/exportfs/io.c/
#include <u.h>
#include <libc.h>
#include <fcall.h>
#define Extern
#include "exportfs.h"
#define QIDPATH ((1LL<<48)-1)
vlong newqid = 0;
void (*fcalls[])(Fsrpc*) =
{
[Tversion] Xversion,
[Tauth] Xauth,
[Tflush] Xflush,
[Tattach] Xattach,
[Twalk] Xwalk,
[Topen] slave,
[Tcreate] Xcreate,
[Tclunk] Xclunk,
[Tread] slave,
[Twrite] slave,
[Tremove] Xremove,
[Tstat] Xstat,
[Twstat] Xwstat,
};
/* accounting and debugging counters */
int filecnt;
int freecnt;
int qidcnt;
int qfreecnt;
int ncollision;
/*
* Start serving file requests from the network
*/
void
io(void)
{
Fsrpc *r;
int n;
for(;;) {
r = getsbuf();
n = read9pmsg(0, r->buf, messagesize);
if(n <= 0)
fatal(nil);
if(convM2S(r->buf, n, &r->work) != n)
fatal("convM2S format error");
DEBUG(2, "%F\n", &r->work);
(fcalls[r->work.type])(r);
}
}
void
reply(Fcall *r, Fcall *t, char *err)
{
uchar *data;
int n;
t->tag = r->tag;
t->fid = r->fid;
if(err != nil) {
t->type = Rerror;
t->ename = err;
}
else
t->type = r->type + 1;
DEBUG(2, "\t%F\n", t);
data = malloc(messagesize); /* not mallocz; no need to clear */
if(data == nil)
fatal(Enomem);
n = convS2M(t, data, messagesize);
if(write(1, data, n) != n){
/* not fatal, might have got a note due to flush */
fprint(2, "exportfs: short write in reply: %r\n");
}
free(data);
}
void
mounterror(char *err)
{
Fsrpc *r;
int n;
r = getsbuf();
r->work.tag = NOTAG;
r->work.fid = NOFID;
r->work.type = Rerror;
r->work.ename = err;
n = convS2M(&r->work, r->buf, messagesize);
write(1, r->buf, n);
exits(err);
}
Fid *
getfid(int nr)
{
Fid *f;
for(f = fidhash(nr); f != nil; f = f->next)
if(f->nr == nr)
return f;
return nil;
}
int
freefid(int nr)
{
Fid *f, **l;
char buf[128];
l = &fidhash(nr);
for(f = *l; f != nil; f = f->next) {
if(f->nr == nr) {
if(f->mid) {
snprint(buf, sizeof(buf), "/mnt/exportfs/%d", f->mid);
unmount(0, buf);
psmap[f->mid] = 0;
}
if(f->f != nil) {
freefile(f->f);
f->f = nil;
}
if(f->dir != nil){
free(f->dir);
f->dir = 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 != nil; new = new->next)
if(new->nr == nr)
return nil;
if(fidfree == nil) {
fidfree = emallocz(sizeof(Fid) * Fidchunk);
for(i = 0; i < Fidchunk-1; i++)
fidfree[i].next = &fidfree[i+1];
fidfree[Fidchunk-1].next = nil;
}
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;
}
static struct {
Lock;
Fsrpc *free;
/* statistics */
int nalloc;
int nfree;
} sbufalloc;
Fsrpc *
getsbuf(void)
{
Fsrpc *w;
lock(&sbufalloc);
w = sbufalloc.free;
if(w != nil){
sbufalloc.free = w->next;
w->next = nil;
sbufalloc.nfree--;
unlock(&sbufalloc);
} else {
sbufalloc.nalloc++;
unlock(&sbufalloc);
w = emallocz(sizeof(*w) + messagesize);
}
w->flushtag = NOTAG;
return w;
}
void
putsbuf(Fsrpc *w)
{
w->flushtag = NOTAG;
lock(&sbufalloc);
w->next = sbufalloc.free;
sbufalloc.free = w;
sbufalloc.nfree++;
unlock(&sbufalloc);
}
void
freefile(File *f)
{
File *parent, *child;
while(--f->ref == 0){
freecnt++;
DEBUG(2, "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);
free(f);
f = parent;
}
}
File *
file(File *parent, char *name)
{
Dir *dir;
char *path;
File *f;
DEBUG(2, "\tfile: 0x%p %s name %s\n", parent, parent->name, name);
path = makepath(parent, name);
if(patternfile != nil && excludefile(path)){
free(path);
return nil;
}
dir = dirstat(path);
free(path);
if(dir == nil)
return nil;
for(f = parent->child; f != nil; 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 == nil)
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 = emallocz(n);
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;
if(--q->ref)
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(2, "collision on %s\n", d->name);
/* collision: find a new one */
ncollision++;
path &= QIDPATH;
++newqid;
if(newqid >= (1<<16)){
DEBUG(2, "collision wraparound\n");
newqid = 1;
}
path |= newqid<<48;
DEBUG(2, "assign qid %.16llux\n", path);
}
qidcnt++;
q = emallocz(sizeof(Qidtab));
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;
Proc *m;
if(s != nil) {
va_start(arg, s);
vsnprint(buf, ERRMAX, s, arg);
va_end(arg);
}
/* Clear away the slave children */
for(m = Proclist; m != nil; m = m->next)
postnote(PNPROC, m->pid, "kill");
if(s != nil) {
DEBUG(2, "%s\n", buf);
sysfatal("%s", buf); /* caution: buf could contain '%' */
} else
exits(nil);
}
void*
emallocz(uint n)
{
void *p;
p = mallocz(n, 1);
if(p == nil)
fatal(Enomem);
setmalloctag(p, getcallerpc(&n));
return p;
}
char*
estrdup(char *s)
{
char *t;
t = strdup(s);
if(t == nil)
fatal(Enomem);
setmalloctag(t, getcallerpc(&s));
return t;
}