/*
* Unshare the filesystem structure if it is being shared
*/
static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
struct fs_struct *fs = current->fs;
if (!(unshare_flags & CLONE_FS) || !fs)
return 0;
/* don't need lock here; in the worst case we'll do useless copy */
if (fs->users == 1)
return 0;
*new_fsp = copy_fs_struct(fs);
if (!*new_fsp)
return -ENOMEM;
return 0;
}
static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
struct fs_struct *fs = current->fs;
if (!(unshare_flags & CLONE_FS) || !fs)
return 0;
if (fs->users == 1)
return 0;
*new_fsp = copy_fs_struct(fs);
if (!*new_fsp)
return -ENOMEM;
return 0;
}
int cfs_daemonize_ctxt(char *str) {
cfs_daemonize(str);
#ifndef HAVE_UNSHARE_FS_STRUCT
{
struct task_struct *tsk = current;
struct fs_struct *fs = NULL;
fs = copy_fs_struct(tsk->fs);
if (fs == NULL)
return -ENOMEM;
exit_fs(tsk);
tsk->fs = fs;
}
#else
unshare_fs_struct();
#endif
return 0;
}
static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
{
struct fs_struct *fs = current->fs;
if (clone_flags & CLONE_FS) {
/* tsk->fs is already what we want */
write_lock(&fs->lock);
if (fs->in_exec) {
write_unlock(&fs->lock);
return -EAGAIN;
}
fs->users++;
write_unlock(&fs->lock);
return 0;
}
tsk->fs = copy_fs_struct(fs);
if (!tsk->fs)
return -ENOMEM;
return 0;
}
static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
{
struct fs_struct *fs = current->fs;
if (clone_flags & CLONE_FS) {
spin_lock(&fs->lock);
if (fs->in_exec) {
spin_unlock(&fs->lock);
return -EAGAIN;
}
fs->users++;
spin_unlock(&fs->lock);
return 0;
}
tsk->fs = copy_fs_struct(fs);
if (!tsk->fs)
return -ENOMEM;
return 0;
}
// XXX: need comment here
// XXX: currently only check perms to create here.
// XXX: other checks needed?
static int do_init_dir(cr_location_t *loc, struct file *dirp)
{
int result = 0;
result = cr_permission(dirp->f_dentry->d_inode,
(loc->is_write ? MAY_WRITE : MAY_READ) | MAY_EXEC, NULL);
if (!result) {
loc->fs = copy_fs_struct(current->fs);
if (loc->fs) {
// replace the pwd with that of 'dirp'
cr_set_pwd_file(loc->fs, dirp);
} else {
result = -EINVAL;
}
}
// Error and normal paths exit here
fput(dirp); // We don't hold the filp for a directory
return result;
}
int
__set_personality(u_long personality)
{
struct exec_domain *ep, *oep;
ep = lookup_exec_domain(personality);
if (ep == current_thread_info()->exec_domain) {
current->personality = personality;
return 0;
}
if (atomic_read(¤t->fs->count) != 1) {
struct fs_struct *fsp, *ofsp;
fsp = copy_fs_struct(current->fs);
if (fsp == NULL) {
module_put(ep->module);
return -ENOMEM;
}
task_lock(current);
ofsp = current->fs;
current->fs = fsp;
task_unlock(current);
put_fs_struct(ofsp);
}
/*
* At that point we are guaranteed to be the sole owner of
* current->fs.
*/
current->personality = personality;
oep = current_thread_info()->exec_domain;
current_thread_info()->exec_domain = ep;
set_fs_altroot();
module_put(oep->module);
return 0;
}
/*
* This is the NFS server kernel thread
*/
static void
nfsd(struct svc_rqst *rqstp)
{
struct svc_serv *serv = rqstp->rq_server;
struct fs_struct *fsp;
int err;
struct nfsd_list me;
sigset_t shutdown_mask, allowed_mask;
/* Lock module and set up kernel thread */
lock_kernel();
daemonize("nfsd");
current->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
/* After daemonize() this kernel thread shares current->fs
* with the init process. We need to create files with a
* umask of 0 instead of init's umask. */
fsp = copy_fs_struct(current->fs);
if (!fsp) {
printk("Unable to start nfsd thread: out of memory\n");
goto out;
}
exit_fs(current);
current->fs = fsp;
current->fs->umask = 0;
siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
siginitsetinv(&allowed_mask, ALLOWED_SIGS);
nfsdstats.th_cnt++;
lockd_up(); /* start lockd */
me.task = current;
list_add(&me.list, &nfsd_list);
unlock_kernel();
/*
* We want less throttling in balance_dirty_pages() so that nfs to
* localhost doesn't cause nfsd to lock up due to all the client's
* dirty pages.
*/
current->flags |= PF_LESS_THROTTLE;
/*
* The main request loop
*/
for (;;) {
/* Block all but the shutdown signals */
sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
/*
* Find a socket with data available and call its
* recvfrom routine.
*/
while ((err = svc_recv(serv, rqstp,
60*60*HZ)) == -EAGAIN)
;
if (err < 0)
break;
update_thread_usage(atomic_read(&nfsd_busy));
atomic_inc(&nfsd_busy);
/* Lock the export hash tables for reading. */
exp_readlock();
/* Process request with signals blocked. */
sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
svc_process(serv, rqstp);
/* Unlock export hash tables */
exp_readunlock();
update_thread_usage(atomic_read(&nfsd_busy));
atomic_dec(&nfsd_busy);
}
if (err != -EINTR) {
printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
} else {
unsigned int signo;
for (signo = 1; signo <= _NSIG; signo++)
if (sigismember(¤t->pending.signal, signo) &&
!sigismember(¤t->blocked, signo))
break;
err = signo;
}
lock_kernel();
/* Release lockd */
lockd_down();
/* Check if this is last thread */
if (serv->sv_nrthreads==1) {
printk(KERN_WARNING "nfsd: last server has exited\n");
if (err != SIG_NOCLEAN) {
printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
nfsd_export_flush();
}
nfsd_serv = NULL;
nfsd_racache_shutdown(); /* release read-ahead cache */
nfs4_state_shutdown();
}
list_del(&me.list);
nfsdstats.th_cnt --;
out:
/* Release the thread */
svc_exit_thread(rqstp);
/* Release module */
module_put_and_exit(0);
}
