/*
 * Copyright IBM Corp. 2008
 *
 * lxc_exec.c: example on creating a linux container
 *
 * Authors:
 * David L. Leskovec <dlesko at linux.vnet.ibm.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 *
 */

/* System includes */
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <unistd.h>

/* Supporting includes */

/* Component includes */

/* Defines */
/* These will eventually be defined in clone.h */
#define CLONE_NEWPID 	0x20000000
#define	CLONE_NEWNS     0x00020000

/* Global Variables */

/* Types and structs */

/* Functions */
static void
exec_child()
{
    FILE *cdfp;
    int rc;

    cdfp = fopen("/tmp/child.log", "w");
	if (cdfp == NULL)
    {
		/* Log to syslog */
		exit(1);
	}

    /* mount /proc */
    rc = mount("lxcproc", "/proc", "proc", 0, NULL);
    if(0 != rc)
    {
	    fprintf(cdfp, "mount failed with rc = %d and errno = %d\n", rc, errno); fflush(cdfp);
        exit(1);
    }
    else
    {
	    fprintf(cdfp, "mount successful\n"); fflush(cdfp);
    }

    system("ps -aef > /tmp/container_ps.out");

    /* sleep a bit just so we don't exit right away */
    sleep(10);

    fclose(cdfp);

}

int main(int argc, char *argv[])
{
    FILE *dfp;
	int cpid;
	void *childstack, *stack;
	int flags;
    int stacksize = getpagesize() * 4;

	dfp = fopen("/tmp/parent.log", "w");
	if(dfp == NULL)
    {
		perror("parent.log");
		exit(1);
	}

    /* allocate a stack for the container */
	stack = malloc(stacksize);
	if(!stack)
    {
		fprintf(dfp, "malloc() failed, %s\n", strerror(errno));
		fflush(dfp);
		exit(1);
	}
    /* point to "top" of stack */
    childstack = stack + stacksize;

    /* call clone to create the container */
	flags = CLONE_NEWPID|CLONE_NEWNS;
	fprintf(dfp, "Parent: Clone() flags %lx, pagesize %d...\n",
			flags, getpagesize());
	fflush(dfp);
	
	cpid = clone(exec_child, childstack, flags, (void *)argv);
    printf("cpid: %d\n", cpid);

	if(cpid < 0)
    {
		fprintf(dfp, "Parent: clone() failed, %s\n",
				strerror(errno));
		fflush(dfp);
		exit(1);
	}

	fprintf(dfp, "Parent sleeping, 20 seconds\n"); fflush(dfp);
	sleep(20);

    return 0;
}