/*
 *  linux/kernel/vserver/legacy.c
 *
 *  Virtual Server: Legacy Funtions
 *
 *  Copyright (C) 2001-2003  Jacques Gelinas
 *  Copyright (C) 2003-2004  Herbert Pötzl
 *
 *  V0.01  broken out from vcontext.c V0.05
 *
 */

#include <linux/config.h>
//#include <linux/linkage.h>
//#include <linux/utsname.h>
//#include <linux/slab.h>
#include <linux/vserver/context.h>
#include <linux/vserver/legacy.h>
//#include <linux/vswitch.h>
#include <linux/vinline.h>
#include <linux/sched.h>
//#include <linux/kernel_stat.h>

#include <asm/errno.h>
#include <asm/uaccess.h>


static int vx_migrate_user(struct task_struct *p, struct vx_info *vxi)
{
	struct user_struct *new_user, *old_user;
	
	if (!p || !vxi)
		BUG();
	new_user = alloc_uid(vxi->vx_id, p->uid);
	if (!new_user)
		return -ENOMEM;

	old_user = p->user;
	if (new_user != old_user) {
		atomic_inc(&new_user->processes);
		atomic_dec(&old_user->processes);
		p->user = new_user;
	}
	free_uid(old_user);
	return 0;
}

/*
 *	migrate task to new context
 *	gets vxi, puts old_vxi on change
 */

static int vx_migrate_task(struct task_struct *p, struct vx_info *vxi)
{
	struct vx_info *old_vxi = task_get_vx_info(p);
	int ret = 0;
	
	if (!p || !vxi)
		BUG();

	vxdprintk("vx_migrate_task(%p,%p[#%d.%d)\n", p, vxi,
		vxi->vx_id, atomic_read(&vxi->vx_refcount));
	spin_lock(&p->alloc_lock);
	if (old_vxi == vxi)
		goto out;

	if (!(ret = vx_migrate_user(p, vxi))) {
		if (old_vxi) {
			old_vxi->virt.nr_threads--;
			atomic_dec(&old_vxi->limit.res[RLIMIT_NPROC]);
		}		
		vxi->virt.nr_threads++;
		atomic_inc(&vxi->limit.res[RLIMIT_NPROC]);
		p->vx_info = get_vx_info(vxi);
		p->xid = vxi->vx_id;
		if (old_vxi)
			put_vx_info(old_vxi);
	}
out:
	spin_unlock(&p->alloc_lock);
	put_vx_info(old_vxi);
	return ret;
}


static int vx_set_initpid(struct vx_info *vxi, int pid)
{
	int ret = 0;
	if (vxi->vx_initpid)
		ret = -EPERM;
	else
		vxi->vx_initpid = pid;
	return ret;
}

int vc_new_s_context(uint32_t ctx, void *data)
{
	int ret = -ENOMEM;
	struct vcmd_new_s_context_v1 vc_data;
	struct vx_info *new_vxi;

	if (copy_from_user(&vc_data, data, sizeof(vc_data)))
		return -EFAULT;

	/* legacy hack, will be removed soon */
	if (ctx == -2) {
		/* assign flags and initpid */
		if (!current->vx_info)
			return -EINVAL;
		ret = 0;
		if (vc_data.flags & VX_INFO_INIT)
			ret = vx_set_initpid(current->vx_info, current->tgid);
		if (ret == 0) {
			/* We keep the same vx_id, but lower the capabilities */
			current->cap_bset &= (~vc_data.remove_cap);
			ret = vx_current_xid();
			current->vx_info->vx_flags |= vc_data.flags;
		}
		return ret;
	}
	
	if (!vx_check(0, VX_ADMIN) ||
		!capable(CAP_SYS_ADMIN) ||
		(current->vx_info &&
		(current->vx_info->vx_flags & VX_INFO_LOCK)))
		return -EPERM;

	if (((ctx > MAX_S_CONTEXT) && (ctx != VX_DYNAMIC_ID)) ||
		(ctx == 0))
		return -EINVAL;
		
	if ((ctx == VX_DYNAMIC_ID) || (ctx < MIN_D_CONTEXT))
		new_vxi = find_or_create_vx_info(ctx);
	else
		new_vxi = find_vx_info(ctx);
		
	if (!new_vxi)
		return -EINVAL;

	ret = vx_migrate_task(current, new_vxi);
	if (ret == 0) {
		current->cap_bset &= (~vc_data.remove_cap);
		new_vxi->vx_flags |= vc_data.flags;
		if (vc_data.flags & VX_INFO_INIT)
			vx_set_initpid(new_vxi, current->tgid);
		if (vc_data.flags & VX_INFO_NPROC)
			new_vxi->limit.rlim[RLIMIT_NPROC] =
				current->rlim[RLIMIT_NPROC].rlim_max;
		ret = new_vxi->vx_id;
	}
	put_vx_info(new_vxi);
	return ret;
}



/*  set ipv4 root (syscall) */

int vc_set_ipv4root(uint32_t nbip, void *data)
{
	int i, err = -EPERM;
	struct vcmd_set_ipv4root_v3 vc_data;
	struct ip_info *new_ipi, *ipi = current->ip_info;

	if (nbip < 0 || nbip > NB_IPV4ROOT)
		return -EINVAL;
	if (copy_from_user (&vc_data, data, sizeof(vc_data)))
		return -EFAULT;

	if (!ipi || ipi->ipv4[0] == 0 || capable(CAP_NET_ADMIN))
		// We are allowed to change everything
		err = 0;
	else if (ipi) {
		int found = 0;
		
		// We are allowed to select a subset of the currently
		// installed IP numbers. No new one allowed
		// We can't change the broadcast address though
		for (i=0; i<nbip; i++) {
			int j;
			__u32 ipip = vc_data.ip_mask_pair[i].ip;
			for (j=0; j<ipi->nbipv4; j++) {
				if (ipip == ipi->ipv4[j]) {
					found++;
					break;
				}
			}
		}
		if ((found == nbip) &&
			(vc_data.broadcast == ipi->v4_bcast))
			err = 0;
	}
	if (err)
		return err;

	new_ipi = create_ip_info();
	if (!new_ipi)
		return -EINVAL;

	new_ipi->nbipv4 = nbip;
	for (i=0; i<nbip; i++) {
		new_ipi->ipv4[i] = vc_data.ip_mask_pair[i].ip;
		new_ipi->mask[i] = vc_data.ip_mask_pair[i].mask;
	}
	new_ipi->v4_bcast = vc_data.broadcast;
	current->ip_info = new_ipi;
	put_ip_info(ipi);
	return 0;
}