ref: 7768cd9a6ec11b04eb2ff6336018cd22fa79f5ea
dir: /kern/syscall.c/
#include "u.h"
#include "lib.h"
#include "dat.h"
#include "fns.h"
#include "error.h"
Chan*
fdtochan(int fd, int mode, int chkmnt, int iref)
{
Fgrp *f;
Chan *c;
c = 0;
f = up->fgrp;
lock(&f->ref.lk);
if(fd<0 || NFD<=fd || (c = f->fd[fd])==0) {
unlock(&f->ref.lk);
error(Ebadfd);
}
if(iref)
refinc(&c->ref);
unlock(&f->ref.lk);
if(chkmnt && (c->flag&CMSG))
goto bad;
if(mode<0 || c->mode==ORDWR)
return c;
if((mode&OTRUNC) && c->mode==OREAD)
goto bad;
if((mode&~OTRUNC) != c->mode)
goto bad;
return c;
bad:
if(iref)
cclose(c);
error(Ebadusefd);
return nil; /* shut up compiler */
}
static void
fdclose(int fd, int flag)
{
int i;
Chan *c;
Fgrp *f;
f = up->fgrp;
lock(&f->ref.lk);
c = f->fd[fd];
if(c == 0) {
unlock(&f->ref.lk);
return;
}
if(flag) {
if(c==0 || !(c->flag&flag)) {
unlock(&f->ref.lk);
return;
}
}
f->fd[fd] = 0;
if(fd == f->maxfd)
for(i=fd; --i>=0 && f->fd[i]==0; )
f->maxfd = i;
unlock(&f->ref.lk);
cclose(c);
}
static int
newfd(Chan *c)
{
int i;
Fgrp *f;
f = up->fgrp;
lock(&f->ref.lk);
for(i=0; i<NFD; i++)
if(f->fd[i] == 0){
if(i > f->maxfd)
f->maxfd = i;
f->fd[i] = c;
unlock(&f->ref.lk);
return i;
}
unlock(&f->ref.lk);
error("no file descriptors");
return 0;
}
int
sysclose(int fd)
{
if(waserror())
return -1;
fdtochan(fd, -1, 0, 0);
fdclose(fd, 0);
poperror();
return 0;
}
int
syscreate(char *path, int mode, ulong perm)
{
int fd;
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
openmode(mode); /* error check only */
c = namec(path, Acreate, mode, perm);
fd = newfd((Chan*)c);
poperror();
return fd;
}
int
sysdup(int old, int new)
{
Chan *oc;
Fgrp *f = up->fgrp;
Chan *c = 0;
if(waserror())
return -1;
c = fdtochan(old, -1, 0, 1);
if(new != -1) {
if(new < 0 || NFD <= new) {
cclose(c);
error(Ebadfd);
}
lock(&f->ref.lk);
if(new > f->maxfd)
f->maxfd = new;
oc = f->fd[new];
f->fd[new] = (Chan*)c;
unlock(&f->ref.lk);
if(oc != 0)
cclose(oc);
}
else {
if(waserror()) {
cclose(c);
nexterror();
}
new = newfd((Chan*)c);
poperror();
}
poperror();
return new;
}
int
sysfstat(int fd, char *buf)
{
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
c = fdtochan(fd, -1, 0, 1);
devtab[c->type]->stat((Chan*)c, buf);
poperror();
cclose(c);
return 0;
}
int
sysfwstat(int fd, char *buf)
{
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
nameok(buf);
c = fdtochan(fd, -1, 1, 1);
devtab[c->type]->wstat((Chan*)c, buf);
poperror();
cclose(c);
return 0;
}
int
syschdir(char *dir)
{
return 0;
}
long
bindmount(Chan *c0, char *old, int flag, char *spec)
{
int ret;
Chan *c1 = 0;
if(flag>MMASK || (flag&MORDER) == (MBEFORE|MAFTER))
error(Ebadarg);
c1 = namec(old, Amount, 0, 0);
if(waserror()){
cclose(c1);
nexterror();
}
ret = cmount(c0, c1, flag, spec);
poperror();
cclose(c1);
return ret;
}
int
sysbind(char *new, char *old, int flags)
{
long r;
Chan *c0 = 0;
if(waserror()) {
cclose(c0);
return -1;
}
c0 = namec(new, Aaccess, 0, 0);
r = bindmount(c0, old, flags, "");
poperror();
cclose(c0);
return 0;
}
int
sysmount(int fd, char *old, int flags, char *spec)
{
long r;
Chan *c0 = 0, *bc = 0;
struct {
Chan* chan;
char* spec;
int flags;
} mntparam;
if(waserror()) {
cclose(bc);
cclose(c0);
return -1;
}
bc = fdtochan(fd, ORDWR, 0, 1);
mntparam.chan = (Chan*)bc;
mntparam.spec = spec;
mntparam.flags = flags;
c0 = (*devtab[devno('M', 0)].attach)(&mntparam);
cclose(bc);
r = bindmount(c0, old, flags, spec);
poperror();
cclose(c0);
return r;
}
int
sysunmount(char *old, char *new)
{
Chan *cmount = 0, *cmounted = 0;
if(waserror()) {
cclose(cmount);
cclose(cmounted);
return -1;
}
cmount = namec(new, Amount, OREAD, 0);
if(old != 0)
cmounted = namec(old, Aopen, OREAD, 0);
cunmount(cmount, cmounted);
poperror();
cclose(cmount);
cclose(cmounted);
return 0;
}
int
sysopen(char *path, int mode)
{
int fd;
Chan *c = 0;
if(waserror()){
cclose(c);
return -1;
}
openmode(mode); /* error check only */
c = namec(path, Aopen, mode, 0);
fd = newfd((Chan*)c);
poperror();
return fd;
}
long
unionread(Chan *c, void *va, long n)
{
long nr;
Chan *nc = 0;
Pgrp *pg = 0;
pg = up->pgrp;
rlock(&pg->ns);
for(;;) {
if(waserror()) {
runlock(&pg->ns);
nexterror();
}
nc = clone(c->mnt->to, 0);
poperror();
if(c->mountid != c->mnt->mountid) {
runlock(&pg->ns);
cclose(nc);
return 0;
}
/* Error causes component of union to be skipped */
if(waserror()) {
cclose(nc);
goto next;
}
nc = (*devtab[nc->type].open)((Chan*)nc, OREAD);
nc->offset = c->offset;
nr = (*devtab[nc->type].read)((Chan*)nc, va, n, nc->offset);
/* devdirread e.g. changes it */
c->offset = nc->offset;
poperror();
cclose(nc);
if(nr > 0) {
runlock(&pg->ns);
return nr;
}
/* Advance to next element */
next:
c->mnt = c->mnt->next;
if(c->mnt == 0)
break;
c->mountid = c->mnt->mountid;
c->offset = 0;
}
runlock(&pg->ns);
return 0;
}
long
sysread(int fd, void *va, long n)
{
int dir;
Lock *cl;
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
c = fdtochan(fd, OREAD, 1, 1);
dir = c->qid.path&CHDIR;
if(dir) {
n -= n%DIRLEN;
if(c->offset%DIRLEN || n==0)
error(Etoosmall);
}
if(dir && c->mnt)
n = unionread((Chan*)c, va, n);
else
n = (*devtab[c->type].read)((Chan*)c, va, n, c->offset);
cl = (Lock*)&c->r.l;
lock(cl);
c->offset += n;
unlock(cl);
poperror();
cclose(c);
return n;
}
int
sysremove(char *path)
{
Chan *c = 0;
if(waserror()) {
if(c != 0)
c->type = 0; /* see below */
cclose(c);
return -1;
}
c = namec(path, Aaccess, 0, 0);
(*devtab[c->type].remove)((Chan*)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;
}
long
sysseek(int fd, long off, int whence)
{
Dir dir;
Chan *c;
char buf[DIRLEN];
if(waserror())
return -1;
c = fdtochan(fd, -1, 1, 0);
if(c->qid.path & CHDIR)
error(Eisdir);
switch(whence) {
case 0:
c->offset = off;
break;
case 1:
lock(&c->r.l); /* lock for read/write update */
c->offset += off;
off = c->offset;
unlock(&c->r.l);
break;
case 2:
(*devtab[c->type].stat)(c, buf);
convM2D(buf, &dir);
c->offset = dir.length + off;
off = c->offset;
break;
}
poperror();
return off;
}
int
sysstat(char *path, char *buf)
{
Chan *c = 0;
if(waserror()){
cclose(c);
return -1;
}
c = namec(path, Aaccess, 0, 0);
(*devtab[c->type].stat)((Chan*)c, buf);
poperror();
cclose(c);
return 0;
}
long
syswrite(int fd, void *va, long n)
{
Lock *cl;
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
c = fdtochan(fd, OWRITE, 1, 1);
if(c->qid.path & CHDIR)
error(Eisdir);
n = (*devtab[c->type].write)((Chan*)c, va, n, c->offset);
cl = (Lock*)&c->r.l;
lock(cl);
c->offset += n;
unlock(cl);
poperror();
cclose(c);
return n;
}
int
syswstat(char *path, char *buf)
{
Chan *c = 0;
if(waserror()) {
cclose(c);
return -1;
}
nameok(buf);
c = namec(path, Aaccess, 0, 0);
(*devtab[c->type].wstat)((Chan*)c, buf);
poperror();
cclose(c);
return 0;
}
int
sysdirstat(char *name, Dir *dir)
{
char buf[DIRLEN];
if(sysstat(name, buf) == -1)
return -1;
convM2D(buf, dir);
return 0;
}
int
sysdirfstat(int fd, Dir *dir)
{
char buf[DIRLEN];
if(sysfstat(fd, buf) == -1)
return -1;
convM2D(buf, dir);
return 0;
}
int
sysdirwstat(char *name, Dir *dir)
{
char buf[DIRLEN];
convD2M(dir, buf);
return syswstat(name, buf);
}
int
sysdirfwstat(int fd, Dir *dir)
{
char buf[DIRLEN];
convD2M(dir, buf);
return sysfwstat(fd, buf);
}
long
sysdirread(int fd, Dir *dbuf, long count)
{
int c, n, i, r;
char buf[DIRLEN*50];
n = 0;
count = (count/sizeof(Dir)) * DIRLEN;
while(n < count) {
c = count - n;
if(c > sizeof(buf))
c = sizeof(buf);
r = sysread(fd, buf, c);
if(r == 0)
break;
if(r < 0 || r % DIRLEN)
return -1;
for(i=0; i<r; i+=DIRLEN) {
convM2D(buf+i, dbuf);
dbuf++;
}
n += r;
if(r != c)
break;
}
return (n/DIRLEN) * sizeof(Dir);
}
static int
call(char *clone, char *dest, int *cfdp, char *dir, char *local)
{
int fd, cfd, n;
char *p, name[3*NAMELEN+5], data[3*NAMELEN+10];
cfd = sysopen(clone, ORDWR);
if(cfd < 0){
werrstr("%s: %r", clone);
return -1;
}
/* get directory name */
n = sysread(cfd, name, sizeof(name)-1);
if(n < 0) {
sysclose(cfd);
return -1;
}
name[n] = 0;
sprint(name, "%d", strtoul(name, 0, 0));
p = strrchr(clone, '/');
*p = 0;
if(dir)
snprint(dir, 2*NAMELEN, "%s/%s", clone, name);
snprint(data, sizeof(data), "%s/%s/data", clone, name);
/* connect */
/* set local side (port number, for example) if we need to */
if(local)
snprint(name, sizeof(name), "connect %s %s", dest, local);
else
snprint(name, sizeof(name), "connect %s", dest);
if(syswrite(cfd, name, strlen(name)) < 0){
werrstr("%s failed: %r", name);
sysclose(cfd);
return -1;
}
/* open data connection */
fd = sysopen(data, ORDWR);
if(fd < 0){
werrstr("can't open %s: %r", data);
sysclose(cfd);
return -1;
}
if(cfdp)
*cfdp = cfd;
else
sysclose(cfd);
return fd;
}
int
sysdial(char *dest, char *local, char *dir, int *cfdp)
{
int n, fd, rv;
char *p, net[128], clone[NAMELEN+12];
/* go for a standard form net!... */
p = strchr(dest, '!');
if(p == 0){
snprint(net, sizeof(net), "net!%s", dest);
} else {
strncpy(net, dest, sizeof(net)-1);
net[sizeof(net)-1] = 0;
}
/* call the connection server */
fd = sysopen("/net/cs", ORDWR);
if(fd < 0){
/* no connection server, don't translate */
p = strchr(net, '!');
*p++ = 0;
snprint(clone, sizeof(clone), "/net/%s/clone", net);
return call(clone, p, cfdp, dir, local);
}
/*
* send dest to connection to translate
*/
if(syswrite(fd, net, strlen(net)) < 0){
werrstr("%s: %r", net);
sysclose(fd);
return -1;
}
/*
* loop through each address from the connection server till
* we get one that works.
*/
rv = -1;
sysseek(fd, 0, 0);
while((n = sysread(fd, net, sizeof(net) - 1)) > 0){
net[n] = 0;
p = strchr(net, ' ');
if(p == 0)
continue;
*p++ = 0;
rv = call(net, p, cfdp, dir, local);
if(rv >= 0)
break;
}
sysclose(fd);
return rv;
}
static int
identtrans(char *addr, char *naddr, int na, char *file, int nf)
{
char *p;
char reply[4*NAMELEN];
/* parse the network */
strncpy(reply, addr, sizeof(reply));
reply[sizeof(reply)-1] = 0;
p = strchr(reply, '!');
if(p)
*p++ = 0;
sprint(file, "/net/%.*s/clone", na - sizeof("/net//clone"), reply);
strncpy(naddr, p, na);
naddr[na-1] = 0;
return 1;
}
static int
nettrans(char *addr, char *naddr, int na, char *file, int nf)
{
long n;
int fd;
char *cp;
char reply[4*NAMELEN];
/*
* ask the connection server
*/
fd = sysopen("/net/cs", ORDWR);
if(fd < 0)
return identtrans(addr, naddr, na, file, nf);
if(syswrite(fd, addr, strlen(addr)) < 0){
sysclose(fd);
return -1;
}
sysseek(fd, 0, 0);
n = sysread(fd, reply, sizeof(reply)-1);
sysclose(fd);
if(n <= 0)
return -1;
reply[n] = '\0';
/*
* parse the reply
*/
cp = strchr(reply, ' ');
if(cp == 0)
return -1;
*cp++ = 0;
strncpy(naddr, cp, na);
naddr[na-1] = 0;
strncpy(file, reply, nf);
file[nf-1] = 0;
return 0;
}
int
sysannounce(char *addr, char *dir)
{
char *cp;
int ctl, n, m;
char buf[3*NAMELEN];
char buf2[3*NAMELEN];
char netdir[2*NAMELEN];
char naddr[3*NAMELEN];
/*
* translate the address
*/
if(nettrans(addr, naddr, sizeof(naddr), netdir, sizeof(netdir)) < 0){
werrstr("can't translate address");
return -1;
}
/*
* get a control channel
*/
ctl = sysopen(netdir, ORDWR);
if(ctl<0){
werrstr("can't open control channel");
return -1;
}
cp = strrchr(netdir, '/');
*cp = 0;
/*
* find out which line we have
*/
n = sprint(buf, "%.*s/", 2*NAMELEN+1, netdir);
m = sysread(ctl, &buf[n], sizeof(buf)-n-1);
if(m <= 0) {
sysclose(ctl);
werrstr("can't read control file");
return -1;
}
buf[n+m] = 0;
/*
* make the call
*/
n = sprint(buf2, "announce %.*s", 2*NAMELEN, naddr);
if(syswrite(ctl, buf2, n) != n) {
sysclose(ctl);
werrstr("announcement fails");
return -1;
}
strcpy(dir, buf);
return ctl;
}
int
syslisten(char *dir, char *newdir)
{
char *cp;
int ctl, n, m;
char buf[3*NAMELEN];
/*
* open listen, wait for a call
*/
sprint(buf, "%.*s/listen", 2*NAMELEN+1, dir);
ctl = sysopen(buf, ORDWR);
if(ctl < 0)
return -1;
/*
* find out which line we have
*/
strcpy(buf, dir);
cp = strrchr(buf, '/');
*++cp = 0;
n = cp-buf;
m = sysread(ctl, cp, sizeof(buf) - n - 1);
if(n<=0){
sysclose(ctl);
return -1;
}
buf[n+m] = 0;
strcpy(newdir, buf);
return ctl;
}