/*
// AUTHOR
// James Quick <jq@quick.com>
// N. Nielsen
//
// LICENSE
// This software is in the public domain.
//
// The software is provided "as is", without warranty of any kind,
// express or implied, including but not limited to the warranties
// of merchantability, fitness for a particular purpose, and
// noninfringement. In no event shall the author(s) be liable for any
// claim, damages, or other liability, whether in an action of
// contract, tort, or otherwise, arising from, out of, or in connection
// with the software or the use or other dealings in the software.
//
// SUPPORT
// Send bug reports to: <nielsen@memberwebs.com>
//
// injail
// A utility function to determine if a process is running in a FreeBSD jail.
//
// This code was written by James E. Quick mailto:jq@quick.com
// The code may be freely re-used under the terms of the BSD copyright,
// as long as this comment remains intact.
*/

#include <kvm.h>
#include <sys/param.h>
#include <paths.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/sysctl.h>
#include <sys/file.h>
#include <stdio.h>

#if __FreeBSD_version > 500000
#define P_FLAG	ki_flag
#else
#define P_FLAG	kp_proc.p_flag
#endif

/* int injail()
* Return 1 if running in a jail, 0 if not, -1 on error
* jq 05/28/2002
*/
int injail ()
{
	int count = 0;
	kvm_t* kd = 0;
	struct kinfo_proc* kp;
	char *memf, *nlistf, *swapf, errbuf[_POSIX2_LINE_MAX];
	int	result = -1;

	memf = nlistf = swapf = _PATH_DEVNULL;
	kd = kvm_openfiles(nlistf, memf, swapf, O_RDONLY, errbuf);
	if(kd)
	{
		kp = kvm_getprocs(kd, KERN_PROC_PID, getpid(), &count);
		if(kp)
			result = (kp->P_FLAG & P_JAILED) ? 1 : 0;
		kvm_close(kd);
	}

	return result;
}