* The sys*() routines needn't poperror() as they return directly to syscall().

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"

/*
* The sys*() routines needn't poperror() as they return directly to syscall().
*/

static void
unlockfgrp(Fgrp *f)
{
int ex;

ex = f->exceed;
f->exceed = 0;
unlock(f);
if(ex)
pprint("warning: process exceeds %d file descriptors\n", ex);
}

int
growfd(Fgrp *f, int fd) /* fd is always >= 0 */
{
Chan **newfd, **oldfd;

if(fd < f->nfd)
return 0;
if(fd >= f->nfd+DELTAFD)
return -1; /* out of range */
/*
* Unbounded allocation is unwise; besides, there are only 16 bits
* of fid in 9P
*/
if(f->nfd >= 5000){
Exhausted:
print("no free file descriptors\n");
return -1;
}
newfd = malloc((f->nfd+DELTAFD)*sizeof(Chan*));
if(newfd == nil)
goto Exhausted;
oldfd = f->fd;
memmove(newfd, oldfd, f->nfd*sizeof(Chan*));
f->fd = newfd;
free(oldfd);
f->nfd += DELTAFD;
if(fd > f->maxfd){
if(fd/100 > f->maxfd/100)
f->exceed = (fd/100)*100;
f->maxfd = fd;
}
return 1;
}

/*
* this assumes that the fgrp is locked
*/
int
findfreefd(Fgrp *f, int start)
{
int fd;

for(fd=start; fd<f->nfd; fd++)
if(f->fd[fd] == nil)
break;
if(fd >= f->nfd && growfd(f, fd) < 0)
return -1;
return fd;
}

int
newfd(Chan *c)
{
int fd;
Fgrp *f;

f = up->fgrp;
lock(f);
fd = findfreefd(f, 0);
if(fd < 0){
unlockfgrp(f);
return -1;
}
if(fd > f->maxfd)
f->maxfd = fd;
f->fd[fd] = c;
unlockfgrp(f);
return fd;
}

int
newfd2(int fd[2], Chan *c[2])
{
Fgrp *f;

f = up->fgrp;
lock(f);
fd[0] = findfreefd(f, 0);
if(fd[0] < 0){
unlockfgrp(f);
return -1;
}
fd[1] = findfreefd(f, fd[0]+1);
if(fd[1] < 0){
unlockfgrp(f);
return -1;
}
if(fd[1] > f->maxfd)
f->maxfd = fd[1];
f->fd[fd[0]] = c[0];
f->fd[fd[1]] = c[1];
unlockfgrp(f);
return 0;
}

Chan*
fdtochan(int fd, int mode, int chkmnt, int iref)
{
Chan *c;
Fgrp *f;

c = nil;
f = up->fgrp;

lock(f);
if(fd<0 || f->nfd<=fd || (c = f->fd[fd])==nil) {
unlock(f);
error(Ebadfd);
}
if(iref)
incref(c);
unlock(f);

if(chkmnt && (c->flag&CMSG)) {
if(iref)
cclose(c);
error(Ebadusefd);
}

if(mode<0 || c->mode==ORDWR)
return c;

if((mode&OTRUNC) && c->mode==OREAD) {
if(iref)
cclose(c);
error(Ebadusefd);
}

if((mode&~OTRUNC) != c->mode) {
if(iref)
cclose(c);
error(Ebadusefd);
}
return c;
}

int
openmode(ulong o)
{
o &= ~(OTRUNC|OCEXEC|ORCLOSE);
if(o > OEXEC)
error(Ebadarg);
if(o == OEXEC)
return OREAD;
return o;
}

uintptr
sysfd2path(va_list list)
{
Chan *c;
char *buf;
uint len;
int fd;

fd = va_arg(list, int);
buf = va_arg(list, char*);
len = va_arg(list, uint);
validaddr((uintptr)buf, len, 1);
c = fdtochan(fd, -1, 0, 1);
snprint(buf, len, "%s", chanpath(c));
cclose(c);
return 0;
}

uintptr
syspipe(va_list list)
{
static char *datastr[] = {"data", "data1"};
int fd[2], *ufd;
Chan *c[2];

ufd = va_arg(list, int*);
validaddr((uintptr)ufd, sizeof(fd), 1);
evenaddr((uintptr)ufd);

ufd[0] = ufd[1] = fd[0] = fd[1] = -1;
c[0] = namec("#|", Atodir, 0, 0);
c[1] = nil;
if(waserror()){
cclose(c[0]);
if(c[1] != nil)
cclose(c[1]);
nexterror();
}
c[1] = cclone(c[0]);
if(walk(&c[0], datastr+0, 1, 1, nil) < 0)
error(Egreg);
if(walk(&c[1], datastr+1, 1, 1, nil) < 0)
error(Egreg);
c[0] = devtab[c[0]->type]->open(c[0], ORDWR);
c[1] = devtab[c[1]->type]->open(c[1], ORDWR);
if(newfd2(fd, c) < 0)
error(Enofd);
ufd[0] = fd[0];
ufd[1] = fd[1];
poperror();
return 0;
}

uintptr
sysdup(va_list list)
{
int fd;
Chan *c, *oc;
Fgrp *f = up->fgrp;

fd = va_arg(list, int);

/*
* Close after dup'ing, so date > #d/1 works
*/
c = fdtochan(fd, -1, 0, 1);
fd = va_arg(list, int);
if(fd != -1){
lock(f);
if(fd<0 || growfd(f, fd)<0) {
unlockfgrp(f);
cclose(c);
error(Ebadfd);
}
if(fd > f->maxfd)
f->maxfd = fd;

oc = f->fd[fd];
f->fd[fd] = c;
unlockfgrp(f);
if(oc != nil)
cclose(oc);
}else{
if(waserror()) {
cclose(c);
nexterror();
}
fd = newfd(c);
if(fd < 0)
error(Enofd);
poperror();
}
return (uintptr)fd;
}

uintptr
sysopen(va_list list)
{
int fd;
Chan *c;
char *name;
ulong mode;

name = va_arg(list, char*);
mode = va_arg(list, ulong);
openmode(mode); /* error check only */
validaddr((uintptr)name, 1, 0);
c = namec(name, Aopen, mode, 0);
if(waserror()){
cclose(c);
nexterror();
}
fd = newfd(c);
if(fd < 0)
error(Enofd);
poperror();
return (uintptr)fd;
}

void
fdclose(int fd, int flag)
{
Chan *c;
Fgrp *f = up->fgrp;

lock(f);
c = fd <= f->maxfd ? f->fd[fd] : nil;
if(c == nil || (flag != 0 && (c->flag&flag) == 0)){
unlock(f);
return;
}
f->fd[fd] = nil;
if(fd == f->maxfd){
while(fd > 0 && f->fd[fd] == nil)
f->maxfd = --fd;
}
unlock(f);
cclose(c);
}

uintptr
sysclose(va_list list)
{
int fd;

fd = va_arg(list, int);
fdtochan(fd, -1, 0, 0);
fdclose(fd, 0);
return 0;
}

long
unionread(Chan *c, void *va, long n)
{
int i;
long nr;
Mhead *m;
Mount *mount;

eqlock(&c->umqlock);
m = c->umh;
rlock(&m->lock);
mount = m->mount;
/* bring mount in sync with c->uri and c->umc */
for(i = 0; mount != nil && i < c->uri; i++)
mount = mount->next;

nr = 0;
while(mount != nil){
/* Error causes component of union to be skipped */
if(mount->to != nil && !waserror()){
if(c->umc == nil){
c->umc = cclone(mount->to);
c->umc = devtab[c->umc->type]->open(c->umc, OREAD);
}

nr = devtab[c->umc->type]->read(c->umc, va, n, c->umc->offset);
c->umc->offset += nr;
poperror();
}
if(nr > 0)
break;

/* Advance to next element */
c->uri++;
if(c->umc != nil){
cclose(c->umc);
c->umc = nil;
}
mount = mount->next;
}
runlock(&m->lock);
qunlock(&c->umqlock);
return nr;
}

static void
unionrewind(Chan *c)
{
eqlock(&c->umqlock);
c->uri = 0;
if(c->umc != nil){
cclose(c->umc);
c->umc = nil;
}
qunlock(&c->umqlock);
}

static int
dirfixed(uchar *p, uchar *e, Dir *d)
{
int len;

len = GBIT16(p)+BIT16SZ;
if(p + len > e)
return -1;

p += BIT16SZ; /* ignore size */
d->type = devno(GBIT16(p), 1);
p += BIT16SZ;
d->dev = GBIT32(p);
p += BIT32SZ;
d->qid.type = GBIT8(p);
p += BIT8SZ;
d->qid.vers = GBIT32(p);
p += BIT32SZ;
d->qid.path = GBIT64(p);
p += BIT64SZ;
d->mode = GBIT32(p);
p += BIT32SZ;
d->atime = GBIT32(p);
p += BIT32SZ;
d->mtime = GBIT32(p);
p += BIT32SZ;
d->length = GBIT64(p);

return len;
}

static char*
dirname(uchar *p, int *n)
{
p += BIT16SZ+BIT16SZ+BIT32SZ+BIT8SZ+BIT32SZ+BIT64SZ
+ BIT32SZ+BIT32SZ+BIT32SZ+BIT64SZ;
*n = GBIT16(p);
return (char*)p+BIT16SZ;
}

static long
dirsetname(char *name, int len, uchar *p, long n, long maxn)
{
char *oname;
int olen;
long nn;

if(n == BIT16SZ)
return BIT16SZ;

oname = dirname(p, &olen);

nn = n+len-olen;
PBIT16(p, nn-BIT16SZ);
if(nn > maxn)
return BIT16SZ;

if(len != olen)
memmove(oname+len, oname+olen, p+n-(uchar*)(oname+olen));
PBIT16((uchar*)(oname-2), len);
memmove(oname, name, len);
return nn;
}

/*
* Mountfix might have caused the fixed results of the directory read
* to overflow the buffer. Catch the overflow in c->dirrock.
*/
static void
mountrock(Chan *c, uchar *p, uchar **pe)
{
uchar *e, *r;
int len, n;

e = *pe;

/* find last directory entry */
for(;;){
len = BIT16SZ+GBIT16(p);
if(p+len >= e)
break;
p += len;
}

/* save it away */
qlock(&c->rockqlock);
if(c->nrock+len > c->mrock){
n = ROUND(c->nrock+len, 1024);
r = smalloc(n);
memmove(r, c->dirrock, c->nrock);
free(c->dirrock);
c->dirrock = r;
c->mrock = n;
}
memmove(c->dirrock+c->nrock, p, len);
c->nrock += len;
qunlock(&c->rockqlock);

/* drop it */
*pe = p;
}

/*
* Satisfy a directory read with the results saved in c->dirrock.
*/
static int
mountrockread(Chan *c, uchar *op, long n, long *nn)
{
long dirlen;
uchar *rp, *erp, *ep, *p;

/* common case */
if(c->nrock == 0)
return 0;

/* copy out what we can */
qlock(&c->rockqlock);
rp = c->dirrock;
erp = rp+c->nrock;
p = op;
ep = p+n;
while(rp+BIT16SZ <= erp){
dirlen = BIT16SZ+GBIT16(rp);
if(p+dirlen > ep)
break;
memmove(p, rp, dirlen);
p += dirlen;
rp += dirlen;
}

if(p == op){
qunlock(&c->rockqlock);
return 0;
}

/* shift the rest */
if(rp != erp)
memmove(c->dirrock, rp, erp-rp);
c->nrock = erp - rp;

*nn = p - op;
qunlock(&c->rockqlock);
return 1;
}

static void
mountrewind(Chan *c)
{
c->nrock = 0;
}

/*
* Rewrite the results of a directory read to reflect current
* name space bindings and mounts. Specifically, replace
* directory entries for bind and mount points with the results
* of statting what is mounted there. Except leave the old names.
*/
static long
mountfix(Chan *c, uchar *op, long n, long maxn)
{
char *name;
int nbuf, nname;
Chan *nc;
Mhead *mh;
Mount *m;
uchar *p;
int dirlen, rest;
long l;
uchar *buf, *e;
Dir d;

p = op;
buf = nil;
nbuf = 0;
for(e=&p[n]; p+BIT16SZ<e; p+=dirlen){
dirlen = dirfixed(p, e, &d);
if(dirlen < 0)
break;
nc = nil;
mh = nil;
if(findmount(&nc, &mh, d.type, d.dev, d.qid)){
/*
* If it's a union directory and the original is
* in the union, don't rewrite anything.
*/
for(m = mh->mount; m != nil; m = m->next)
if(eqchantdqid(m->to, d.type, d.dev, d.qid, 1))
goto Norewrite;

name = dirname(p, &nname);
/*
* Do the stat but fix the name. If it fails, leave old entry.
* BUG: If it fails because there isn't room for the entry,
* what can we do? Nothing, really. Might as well skip it.
*/
if(buf == nil){
buf = smalloc(4096);
nbuf = 4096;
}
if(waserror())
goto Norewrite;
l = devtab[nc->type]->stat(nc, buf, nbuf);
l = dirsetname(name, nname, buf, l, nbuf);
if(l == BIT16SZ)
error("dirsetname");
poperror();

/*
* Shift data in buffer to accomodate new entry,
* possibly overflowing into rock.
*/
rest = e - (p+dirlen);
if(l > dirlen){
while(p+l+rest > op+maxn){
mountrock(c, p, &e);
if(e == p){
dirlen = 0;
goto Norewrite;
}
rest = e - (p+dirlen);
}
}
if(l != dirlen){
memmove(p+l, p+dirlen, rest);
dirlen = l;
e = p+dirlen+rest;
}

/*
* Rewrite directory entry.
*/
memmove(p, buf, l);

Norewrite:
cclose(nc);
putmhead(mh);
}
}
if(buf != nil)
free(buf);

if(p != e)
error("oops in rockfix");

return e-op;
}

static long
read(int fd, uchar *p, long n, vlong *offp)
{
long nn, nnn;
Chan *c;
vlong off;

validaddr((uintptr)p, n, 1);
c = fdtochan(fd, OREAD, 1, 1);

if(waserror()){
cclose(c);
nexterror();
}

/*
* The offset is passed through on directories, normally.
* Sysseek complains, but pread is used by servers like exportfs,
* that shouldn't need to worry about this issue.
*
* Notice that c->devoffset is the offset that c's dev is seeing.
* The number of bytes read on this fd (c->offset) may be different
* due to rewritings in rockfix.
*/
if(offp == nil) /* use and maintain channel's offset */
off = c->offset;
else
off = *offp;
if(off < 0)
error(Enegoff);

if(off == 0){ /* rewind to the beginning of the directory */
if(offp == nil || (c->qid.type & QTDIR)){
c->offset = 0;
c->devoffset = 0;
}
mountrewind(c);
unionrewind(c);
}

if(c->qid.type & QTDIR){
if(mountrockread(c, p, n, &nn)){
/* do nothing: mountrockread filled buffer */
}else if(c->umh != nil)
nn = unionread(c, p, n);
else{
if(off != c->offset)
error(Edirseek);
nn = devtab[c->type]->read(c, p, n, c->devoffset);
}
nnn = mountfix(c, p, nn, n);
}else
nnn = nn = devtab[c->type]->read(c, p, n, off);

if(offp == nil || (c->qid.type & QTDIR)){
lock(c);
c->devoffset += nn;
c->offset += nnn;
unlock(c);
}

poperror();
cclose(c);
return nnn;
}

uintptr
sys_read(va_list list)
{
int fd;
void *buf;
long len;

fd = va_arg(list, int);
buf = va_arg(list, void*);
len = va_arg(list, long);
return (uintptr)read(fd, buf, len, nil);
}

uintptr
syspread(va_list list)
{
int fd;
void *buf;
long len;
vlong off, *offp;

fd = va_arg(list, int);
buf = va_arg(list, void*);
len = va_arg(list, long);
off = va_arg(list, vlong);
if(off != ~0ULL)
offp = &off;
else
offp = nil;
return (uintptr)read(fd, buf, len, offp);
}

static long
write(int fd, void *buf, long len, vlong *offp)
{
Chan *c;
long m, n;
vlong off;

validaddr((uintptr)buf, len, 0);
n = 0;
c = fdtochan(fd, OWRITE, 1, 1);
if(waserror()) {
if(offp == nil){
lock(c);
c->offset -= n;
unlock(c);
}
cclose(c);
nexterror();
}

if(c->qid.type & QTDIR)
error(Eisdir);

n = len;

if(offp == nil){ /* use and maintain channel's offset */
lock(c);
off = c->offset;
c->offset += n;
unlock(c);
}else
off = *offp;

if(off < 0)
error(Enegoff);

m = devtab[c->type]->write(c, buf, n, off);
if(offp == nil && m < n){
lock(c);
c->offset -= n - m;
unlock(c);
}

poperror();
cclose(c);
return m;
}

uintptr
sys_write(va_list list)
{
int fd;
void *buf;
long len;

fd = va_arg(list, int);
buf = va_arg(list, void*);
len = va_arg(list, long);
return (uintptr)write(fd, buf, len, nil);
}

uintptr
syspwrite(va_list list)
{
int fd;
void *buf;
long len;
vlong off, *offp;

fd = va_arg(list, int);
buf = va_arg(list, void*);
len = va_arg(list, long);
off = va_arg(list, vlong);
if(off != ~0ULL)
offp = &off;
else
offp = nil;
return (uintptr)write(fd, buf, len, offp);
}

static vlong
sseek(int fd, vlong o, int type)
{
Chan *c;
uchar buf[sizeof(Dir)+100];
Dir dir;
int n;
vlong off;

c = fdtochan(fd, -1, 1, 1);
if(waserror()){
cclose(c);
nexterror();
}
if(devtab[c->type]->dc == L'|')
error(Eisstream);

off = 0;
switch(type){
case 0:
off = o;
if((c->qid.type & QTDIR) && off != 0)
error(Eisdir);
if(off < 0)
error(Enegoff);
c->offset = off;
break;

case 1:
if(c->qid.type & QTDIR)
error(Eisdir);
lock(c); /* lock for read/write update */
off = o + c->offset;
if(off < 0){
unlock(c);
error(Enegoff);
}
c->offset = off;
unlock(c);
break;

case 2:
if(c->qid.type & QTDIR)
error(Eisdir);
n = devtab[c->type]->stat(c, buf, sizeof buf);
if(convM2D(buf, n, &dir, nil) == 0)
error("internal error: stat error in seek");
off = dir.length + o;
if(off < 0)
error(Enegoff);
c->offset = off;
break;

default:
error(Ebadarg);
}
c->uri = 0;
c->dri = 0;
cclose(c);
poperror();
return off;
}

uintptr
sysseek(va_list list)
{
int fd, t;
vlong n, *v;

v = va_arg(list, vlong*);
evenaddr((uintptr)v);
validaddr((uintptr)v, sizeof(vlong), 1);

fd = va_arg(list, int);
n = va_arg(list, vlong);
t = va_arg(list, int);

*v = sseek(fd, n, t);

return 0;
}

uintptr
sysoseek(va_list list)
{
int fd, t;
long n;

fd = va_arg(list, int);
n = va_arg(list, long);
t = va_arg(list, int);
return (uintptr)sseek(fd, n, t);
}

void
validstat(uchar *s, int n)
{
int m;
char buf[64];

if(statcheck(s, n) < 0)
error(Ebadstat);
/* verify that name entry is acceptable */
s += STATFIXLEN - 4*BIT16SZ; /* location of first string */
/*
* s now points at count for first string.
* if it's too long, let the server decide; this is
* only for his protection anyway. otherwise
* we'd have to allocate and waserror.
*/
m = GBIT16(s);
s += BIT16SZ;
if(m+1 > sizeof buf)
return;
memmove(buf, s, m);
buf[m] = '\0';
/* name could be '/' */
if(strcmp(buf, "/") != 0)
validname(buf, 0);
}

static char*
pathlast(Path *p)
{
char *s;

if(p == nil)
return nil;
if(p->len == 0)
return nil;
s = strrchr(p->s, '/');
if(s != nil)
return s+1;
return p->s;
}

uintptr
sysfstat(va_list list)
{
Chan *c;
int fd;
uint l;
uchar *s;

fd = va_arg(list, int);
s = va_arg(list, uchar*);
l = va_arg(list, uint);
validaddr((uintptr)s, l, 1);

c = fdtochan(fd, -1, 0, 1);
if(waserror()) {
cclose(c);
nexterror();
}
l = devtab[c->type]->stat(c, s, l);
poperror();
cclose(c);
return l;
}

uintptr
sysstat(va_list list)
{
char *name;
Chan *c;
uint l, r;
uchar *s;

name = va_arg(list, char*);
s = va_arg(list, uchar*);
l = va_arg(list, uint);
validaddr((uintptr)s, l, 1);
validaddr((uintptr)name, 1, 0);
c = namec(name, Aaccess, 0, 0);
if(waserror()){
cclose(c);
nexterror();
}
r = devtab[c->type]->stat(c, s, l);
name = pathlast(c->path);
if(name != nil)
r = dirsetname(name, strlen(name), s, r, l);

poperror();
cclose(c);
return r;
}

uintptr
syschdir(va_list list)
{
Chan *c;
char *name;

name = va_arg(list, char*);
validaddr((uintptr)name, 1, 0);
c = namec(name, Atodir, 0, 0);
cclose(up->dot);
up->dot = c;
return 0;
}

long
bindmount(int ismount, int fd, int afd, char* arg0, char* arg1, int flag, char* spec)
{
int ret;
Chan *c0, *c1, *ac, *bc;

if((flag&~MMASK) || (flag&MORDER)==(MBEFORE|MAFTER))
error(Ebadarg);

if(ismount){
validaddr((uintptr)spec, 1, 0);
spec = validnamedup(spec, 1);
if(waserror()){
free(spec);
nexterror();
}

if(up->pgrp->noattach)
error(Enoattach);

ac = nil;
bc = fdtochan(fd, ORDWR, 0, 1);
if(waserror()) {
if(ac != nil)
cclose(ac);
cclose(bc);
nexterror();
}

if(afd >= 0)
ac = fdtochan(afd, ORDWR, 0, 1);

c0 = mntattach(bc, ac, spec, flag&MCACHE);
poperror(); /* ac bc */
if(ac != nil)
cclose(ac);
cclose(bc);
}else{
spec = nil;
validaddr((uintptr)arg0, 1, 0);
c0 = namec(arg0, Abind, 0, 0);
}

if(waserror()){
cclose(c0);
nexterror();
}

validaddr((uintptr)arg1, 1, 0);
c1 = namec(arg1, Amount, 0, 0);
if(waserror()){
cclose(c1);
nexterror();
}

ret = cmount(&c0, c1, flag, spec);

poperror();
cclose(c1);
poperror();
cclose(c0);
if(ismount){
fdclose(fd, 0);
poperror();
free(spec);
}
return ret;
}

uintptr
sysbind(va_list list)
{
char *arg0, *arg1;
int flag;

arg0 = va_arg(list, char*);
arg1 = va_arg(list, char*);
flag = va_arg(list, int);
return (uintptr)bindmount(0, -1, -1, arg0, arg1, flag, nil);
}

uintptr
sysmount(va_list list)
{
char *arg1, *spec;
int flag;
int fd, afd;

fd = va_arg(list, int);
afd = va_arg(list, int);
arg1 = va_arg(list, char*);
flag = va_arg(list, int);
spec = va_arg(list, char*);
return (uintptr)bindmount(1, fd, afd, nil, arg1, flag, spec);
}

uintptr
sys_mount(va_list list)
{
char *arg1, *spec;
int flag;
int fd;

fd = va_arg(list, int);
arg1 = va_arg(list, char*);
flag = va_arg(list, int);
spec = va_arg(list, char*);
return (uintptr)bindmount(1, fd, -1, nil, arg1, flag, spec);
}

uintptr
sysunmount(va_list list)
{
Chan *cmount, *cmounted;
char *name, *old;

name = va_arg(list, char*);
old = va_arg(list, char*);

cmounted = nil;
validaddr((uintptr)old, 1, 0);
cmount = namec(old, Amount, 0, 0);
if(waserror()) {
cclose(cmount);
if(cmounted != nil)
cclose(cmounted);
nexterror();
}
if(name != nil) {
/*
* This has to be namec(..., Aopen, ...) because
* if arg[0] is something like /srv/cs or /fd/0,
* opening it is the only way to get at the real
* Chan underneath.
*/
validaddr((uintptr)name, 1, 0);
cmounted = namec(name, Aopen, OREAD, 0);
}
cunmount(cmount, cmounted);
poperror();
cclose(cmount);
if(cmounted != nil)
cclose(cmounted);
return 0;
}

uintptr
syscreate(va_list list)
{
int fd, mode, perm;
char *name;
Chan *c;

name = va_arg(list, char*);
mode = va_arg(list, int);
perm = va_arg(list, int);
openmode(mode&~OEXCL); /* error check only; OEXCL okay here */
validaddr((uintptr)name, 1, 0);
c = namec(name, Acreate, mode, perm);
if(waserror()) {
cclose(c);
nexterror();
}
fd = newfd(c);
if(fd < 0)
error(Enofd);
poperror();
return (uintptr)fd;
}

uintptr
sysremove(va_list list)
{
char *name;
Chan *c;

name = va_arg(list, char*);
validaddr((uintptr)name, 1, 0);
c = namec(name, Aremove, 0, 0);
/*
* Removing mount points is disallowed to avoid surprises
* (which should be removed: the mount point or the mounted Chan?).
*/
if(c->ismtpt){
cclose(c);
error(Eismtpt);
}
if(waserror()){
c->type = 0; /* see below */
cclose(c);
nexterror();
}
devtab[c->type]->remove(c);
/*
* Remove clunks the fid, but we need to recover the Chan
* so fake it up. rootclose() is known to be a nop.
*/
c->type = 0;
poperror();
cclose(c);
return 0;
}

static long
wstat(Chan *c, uchar *d, int nd)
{
long l;
int namelen;

if(waserror()){
cclose(c);
nexterror();
}
if(c->ismtpt){
/*
* Renaming mount points is disallowed to avoid surprises
* (which should be renamed? the mount point or the mounted Chan?).
*/
dirname(d, &namelen);
if(namelen)
nameerror(chanpath(c), Eismtpt);
}
l = devtab[c->type]->wstat(c, d, nd);
poperror();
cclose(c);
return l;
}

uintptr
syswstat(va_list list)
{
char *name;
uchar *s;
Chan *c;
uint l;

name = va_arg(list, char*);
s = va_arg(list, uchar*);
l = va_arg(list, uint);
validaddr((uintptr)s, l, 0);
validstat(s, l);
validaddr((uintptr)name, 1, 0);
c = namec(name, Aaccess, 0, 0);
return (uintptr)wstat(c, s, l);
}

uintptr
sysfwstat(va_list list)
{
uchar *s;
Chan *c;
uint l;
int fd;

fd = va_arg(list, int);
s = va_arg(list, uchar*);
l = va_arg(list, uint);
validaddr((uintptr)s, l, 0);
validstat(s, l);
c = fdtochan(fd, -1, 1, 1);
return (uintptr)wstat(c, s, l);
}

static void
packoldstat(uchar *buf, Dir *d)
{
uchar *p;
ulong q;

/* lay down old stat buffer - grotty code but it's temporary */
p = buf;
strncpy((char*)p, d->name, 28);
p += 28;
strncpy((char*)p, d->uid, 28);
p += 28;
strncpy((char*)p, d->gid, 28);
p += 28;
q = (ulong)d->qid.path & ~DMDIR; /* make sure doesn't accidentally look like directory */
if(d->qid.type & QTDIR) /* this is the real test of a new directory */
q |= DMDIR;
PBIT32(p, q);
p += BIT32SZ;
PBIT32(p, d->qid.vers);
p += BIT32SZ;
PBIT32(p, d->mode);
p += BIT32SZ;
PBIT32(p, d->atime);
p += BIT32SZ;
PBIT32(p, d->mtime);
p += BIT32SZ;
PBIT64(p, d->length);
p += BIT64SZ;
PBIT16(p, d->type);
p += BIT16SZ;
PBIT16(p, d->dev);
}

uintptr
sys_stat(va_list list)
{
static char old[] = "old stat system call - recompile";
Chan *c;
uint l;
uchar *s, buf[128]; /* old DIRLEN plus a little should be plenty */
char strs[128], *name;
Dir d;

name = va_arg(list, char*);
s = va_arg(list, uchar*);
validaddr((uintptr)s, 116, 1);
validaddr((uintptr)name, 1, 0);
c = namec(name, Aaccess, 0, 0);
if(waserror()){
cclose(c);
nexterror();
}
l = devtab[c->type]->stat(c, buf, sizeof buf);
/* buf contains a new stat buf; convert to old. yuck. */
if(l <= BIT16SZ) /* buffer too small; time to face reality */
error(old);
name = pathlast(c->path);
if(name != nil)
l = dirsetname(name, strlen(name), buf, l, sizeof buf);
l = convM2D(buf, l, &d, strs);
if(l == 0)
error(old);
packoldstat(s, &d);

poperror();
cclose(c);
return 0;
}

uintptr
sys_fstat(va_list list)
{
static char old[] = "old fstat system call - recompile";
Chan *c;
char *name;
uint l;
uchar *s, buf[128]; /* old DIRLEN plus a little should be plenty */
char strs[128];
Dir d;
int fd;

fd = va_arg(list, int);
s = va_arg(list, uchar*);
validaddr((uintptr)s, 116, 1);
c = fdtochan(fd, -1, 0, 1);
if(waserror()){
cclose(c);
nexterror();
}
l = devtab[c->type]->stat(c, buf, sizeof buf);
/* buf contains a new stat buf; convert to old. yuck. */
if(l <= BIT16SZ) /* buffer too small; time to face reality */
error(old);
name = pathlast(c->path);
if(name != nil)
l = dirsetname(name, strlen(name), buf, l, sizeof buf);
l = convM2D(buf, l, &d, strs);
if(l == 0)
error(old);
packoldstat(s, &d);

poperror();
cclose(c);
return 0;
}

uintptr
sys_wstat(va_list)
{
error("old wstat system call - recompile");
return (uintptr)-1;
}

uintptr
sys_fwstat(va_list)
{
error("old fwstat system call - recompile");
return (uintptr)-1;
}