/* Copyright (C) 1998 Joshua Sled

   This file is part of LibGTop 1.0.

   Contributed by Joshua Sled <jsled@xcf.berkeley.edu>, July 1998.

   LibGTop is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License,

   or (at your option) any later version.

   LibGTop 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 General Public License

   for more details.

   You should have received a copy of the GNU General Public License

   along with LibGTop; see the file COPYING. If not, write to the

   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

   Boston, MA 02110-1301, USA.

*/

#include <config.h>

#include <glibtop.h>

#include <glibtop/error.h>

#include <glibtop/cpu.h>

#include <glibtop/open.h>

#include <glibtop/init_hooks.h>

#include <glibtop/machine.h>

/* !!! THIS FUNCTION RUNS SUID ROOT - CHANGE WITH CAUTION !!! */

void

glibtop_init_p (glibtop *server, const unsigned long features,

		const unsigned flags)

{

	const _glibtop_init_func_t *init_fkt;

	if (server == NULL)

		glibtop_error_r (NULL, "glibtop_init_p (server == NULL)");

	/* Do the initialization, but only if not already initialized. */

	if ((server->flags & _GLIBTOP_INIT_STATE_SYSDEPS) == 0) {

		glibtop_open_p (server, "glibtop", features, flags);

		for (init_fkt = _glibtop_init_hook_p; *init_fkt; init_fkt++)

			(*init_fkt) (server);

		server->flags |= _GLIBTOP_INIT_STATE_SYSDEPS;

	}

}

void

glibtop_open_p (glibtop *server, const char *program_name,

		const unsigned long features,

		const unsigned flags)

{

	char errbuf[_POSIX2_LINE_MAX];

	glibtop_debug ("glibtop_open_p ()");

	/* !!! WE ARE ROOT HERE - CHANGE WITH CAUTION !!! */

	server->machine->uid = getuid ();

	server->machine->euid = geteuid ();

	server->machine->gid = getgid ();

	server->machine->egid = getegid ();

	/* Setup machine-specific data */

	server->machine->kd = kvm_openfiles (NULL, NULL, NULL, O_RDONLY, errbuf);

	if (server->machine->kd == NULL)

		glibtop_error_io_r (server, "kvm_open");

	/* Drop priviledges. */

	glibtop_debug ("uid=%d euid=%d gid=%d egid=%d", getuid(), geteuid(), getgid(), getegid());

	if (setreuid (server->machine->euid, server->machine->uid))

		_exit (1);

	if (setregid (server->machine->egid, server->machine->gid))

		_exit (1);

	glibtop_debug ("uid=%d euid=%d gid=%d egid=%d", getuid(), geteuid(), getgid(), getegid());

	/* !!! END OF SUID ROOT PART !!! */

	/* Our effective uid is now those of the user invoking the server,

	 * so we do no longer have any priviledges. */

	/* NOTE: On FreeBSD, we do not need to be suid root, we just need to

	 * be sgid kmem.

	 *

	 * The server will only use setegid() to get back it's priviledges,

	 * so it will fail if it is suid root and not sgid kmem. */

}