servers/pm/getset.c
/* This file handles the 6 system calls that get and set uids and gids.
 * It also handles getpid(), setsid(), and getpgrp().  The code for each
 * one is so tiny that it hardly seemed worthwhile to make each a separate
 * function.
 */

#include "pm.h"
#include <minix/callnr.h>
#include <minix/endpoint.h>
#include <limits.h>
#include <minix/com.h>
#include <signal.h>
#include "mproc.h"
#include "param.h"

/*===========================================================================*
 *				do_get					     *
 *===========================================================================*/
int do_get()
{
/* Handle GETUID, GETGID, GETGROUPS, GETGROUPS_O, GETPID, GETPGRP, GETSID,
   ISSETUGID.
 */

  register struct mproc *rmp = mp;
  int r, i;
  int ngroups;
  char sgroups[NGROUPS_MAX];	/* XXX: Temp storage for GETGROUPS_O */

  switch(call_nr) {
	case GETGROUPS_O:
		ngroups = m_in.grp_no;
		if (ngroups > NGROUPS_MAX || ngroups < 0)
			return(EINVAL);

		if (ngroups == 0) {
			r = rmp->mp_ngroups;
			break;
		}

		if (ngroups < rmp->mp_ngroups)
			/* Asking for less groups than available */
			return(EINVAL);
	
		for (i = 0; i < ngroups; i++)
			sgroups[i] = (char) rmp->mp_sgroups[i];

		r = sys_datacopy(SELF, (vir_bytes) &sgroups, who_e,
			(vir_bytes) m_in.groupsp, ngroups * sizeof(char));

		if (r != OK)
			return(r);

		r = rmp->mp_ngroups;
		break;
	case GETGROUPS:
		ngroups = m_in.grp_no;
		if (ngroups > NGROUPS_MAX || ngroups < 0)
			return(EINVAL);

		if (ngroups == 0) {
			r = rmp->mp_ngroups;
			break;
		}

		if (ngroups < rmp->mp_ngroups)
			/* Asking for less groups than available */
			return(EINVAL);

		r = sys_datacopy(SELF, (vir_bytes) rmp->mp_sgroups, who_e,
			(vir_bytes) m_in.groupsp, ngroups * sizeof(gid_t));

		if (r != OK)
			return(r);

		r = rmp->mp_ngroups;
		break;
	case GETUID:
		r = rmp->mp_realuid;
		rmp->mp_reply.reply_res2 = rmp->mp_effuid;
		break;

	case GETGID:
		r = rmp->mp_realgid;
		rmp->mp_reply.reply_res2 = rmp->mp_effgid;
		break;

	case MINIX_GETPID:
		r = mproc[who_p].mp_pid;
		rmp->mp_reply.reply_res2 = mproc[rmp->mp_parent].mp_pid;
		break;

	case GETPGRP:
		r = rmp->mp_procgrp;
		break;

	case PM_GETSID:
	{
		struct mproc *target;
		pid_t p = m_in.PM_GETSID_PID;
		target = p ? find_proc(p) : &mproc[who_p];
		r = ESRCH;
		if(target)
			r = target->mp_procgrp;
		break;
	}
	case ISSETUGID:
		r = !!(rmp->mp_flags & TAINTED);
		break;

	default:
		r = EINVAL;
		break;	
  }
  return(r);
}

/*===========================================================================*
 *				do_set					     *
 *===========================================================================*/
int do_set()
{
/* Handle SETUID, SETEUID, SETGID, SETEGID, SETSID. These calls have in common
 * that, if successful, they will be forwarded to VFS as well.
 */
  register struct mproc *rmp = mp;
  message m;
  int r, i;
  int ngroups;
  char sgroups[NGROUPS_MAX];	/* XXX: Temp storage for SETGROUPS_O */


  switch(call_nr) {
	case SETUID:
	case SETEUID:
		if (rmp->mp_realuid != (uid_t) m_in.usr_id && 
				rmp->mp_effuid != SUPER_USER)
			return(EPERM);
		if(call_nr == SETUID) rmp->mp_realuid = (uid_t) m_in.usr_id;
		rmp->mp_effuid = (uid_t) m_in.usr_id;

		m.m_type = PM_SETUID;
		m.PM_PROC = rmp->mp_endpoint;
		m.PM_EID = rmp->mp_effuid;
		m.PM_RID = rmp->mp_realuid;

		break;

	case SETGID:
	case SETEGID:
		if (rmp->mp_realgid != (gid_t) m_in.grp_id && 
				rmp->mp_effuid != SUPER_USER)
			return(EPERM);
		if(call_nr == SETGID) rmp->mp_realgid = (gid_t) m_in.grp_id;
		rmp->mp_effgid = (gid_t) m_in.grp_id;

		m.m_type = PM_SETGID;
		m.PM_PROC = rmp->mp_endpoint;
		m.PM_EID = rmp->mp_effgid;
		m.PM_RID = rmp->mp_realgid;

		break;
	case SETGROUPS:
		if (rmp->mp_effuid != SUPER_USER)
			return(EPERM);

		ngroups = m_in.grp_no;

		if (ngroups > NGROUPS_MAX || ngroups < 0) 
			return(EINVAL);

		if (m_in.groupsp == NULL) 
			return(EFAULT);

		r = sys_datacopy(who_e, (vir_bytes) m_in.groupsp, SELF,
			     (vir_bytes) rmp->mp_sgroups,
			     ngroups * sizeof(gid_t));
		if (r != OK) 
			return(r);

		for (i = 0; i < ngroups; i++) {
			if (rmp->mp_sgroups[i] > GID_MAX)
				return(EINVAL);
		}
		for (i = ngroups; i < NGROUPS_MAX; i++) {
			rmp->mp_sgroups[i] = 0;
		}
		rmp->mp_ngroups = ngroups;

		m.m_type = PM_SETGROUPS;
		m.PM_PROC = rmp->mp_endpoint;
		m.PM_GROUP_NO = rmp->mp_ngroups;
		m.PM_GROUP_ADDR = (char *) rmp->mp_sgroups;

		break;
	case SETGROUPS_O:
		if (rmp->mp_effuid != SUPER_USER)
			return(EPERM);

		ngroups = m_in.grp_no;

		if (ngroups > NGROUPS_MAX || ngroups < 0)
			return(EINVAL);

		if (m_in.groupsp == NULL)
			return(EFAULT);

		r = sys_datacopy(who_e, (vir_bytes) m_in.groupsp, SELF,
			     (vir_bytes) &sgroups, ngroups * sizeof(char));
		if (r != OK)
			return(r);

		for (i = 0; i < ngroups; i++)
			rmp->mp_sgroups[i] = (gid_t) sgroups[i];
		for (i = ngroups; i < NGROUPS_MAX; i++)
			rmp->mp_sgroups[i] = 0;
		rmp->mp_ngroups = ngroups;

		m.m_type = PM_SETGROUPS;
		m.PM_PROC = rmp->mp_endpoint;
		m.PM_GROUP_NO = rmp->mp_ngroups;
		m.PM_GROUP_ADDR = (char *) rmp->mp_sgroups;

		break;
	case SETSID:
		if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
		rmp->mp_procgrp = rmp->mp_pid;

		m.m_type = PM_SETSID;
		m.PM_PROC = rmp->mp_endpoint;

		break;

	default:
		return(EINVAL);
  }

  /* Send the request to VFS */
  tell_vfs(rmp, &m);

  /* Do not reply until VFS has processed the request */
  return(SUSPEND);
}
