minix/servers/pm/getset.c

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/* This file handles the 4 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 "mm.h"
#include <minix/callnr.h>
#include <signal.h>
#include "mproc.h"
#include "param.h"
/*===========================================================================*
* do_getset *
*===========================================================================*/
PUBLIC int do_getset()
{
/* Handle GETUID, GETGID, GETPID, GETPGRP, SETUID, SETGID, SETSID. The four
* GETs and SETSID return their primary results in 'r'. GETUID, GETGID, and
* GETPID also return secondary results (the effective IDs, or the parent
* process ID) in 'reply_res2', which is returned to the user.
*/
register struct mproc *rmp = mp;
register int r;
switch(call_nr) {
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 GETPID:
r = mproc[who].mp_pid;
rmp->mp_reply.reply_res2 = mproc[rmp->mp_parent].mp_pid;
break;
case SETUID:
if (rmp->mp_realuid != (uid_t) m_in.usr_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
rmp->mp_realuid = (uid_t) m_in.usr_id;
rmp->mp_effuid = (uid_t) m_in.usr_id;
tell_fs(SETUID, who, rmp->mp_realuid, rmp->mp_effuid);
r = OK;
break;
case SETGID:
if (rmp->mp_realgid != (gid_t) m_in.grp_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
rmp->mp_realgid = (gid_t) m_in.grp_id;
rmp->mp_effgid = (gid_t) m_in.grp_id;
tell_fs(SETGID, who, rmp->mp_realgid, rmp->mp_effgid);
r = OK;
break;
case SETSID:
if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
rmp->mp_procgrp = rmp->mp_pid;
tell_fs(SETSID, who, 0, 0);
/*FALL THROUGH*/
case GETPGRP:
r = rmp->mp_procgrp;
break;
default:
r = EINVAL;
break;
}
return(r);
}