usr/src/sys/kern/kern_prot.c

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *      @(#)kern_prot.c 7.2 (Berkeley) %G%
 */

/*
 * System calls related to processes and protection
 */

#include "../machine/reg.h"

#include "param.h"
#include "systm.h"
#include "dir.h"
#include "user.h"
#include "inode.h"
#include "proc.h"
#include "timeb.h"
#include "times.h"
#include "reboot.h"
#include "fs.h"
#include "buf.h"
#include "mount.h"
#include "quota.h"

getpid()
{

        u.u_r.r_val1 = u.u_procp->p_pid;
        u.u_r.r_val2 = u.u_procp->p_ppid;
}

getpgrp()
{
        register struct a {
                int     pid;
        } *uap = (struct a *)u.u_ap;
        register struct proc *p;

        if (uap->pid == 0)
                p = u.u_procp;
        else if ((p = pfind(uap->pid)) == 0) {
                u.u_error = ESRCH;
                return;
        }
        u.u_r.r_val1 = p->p_pgrp->pg_id;
}

getuid()
{

        u.u_r.r_val1 = u.u_ruid;
        u.u_r.r_val2 = u.u_uid;
}

getgid()
{

        u.u_r.r_val1 = u.u_rgid;
        u.u_r.r_val2 = u.u_gid;
}

getgroups()
{
        register struct a {
                u_int   gidsetsize;
                int     *gidset;
        } *uap = (struct a *)u.u_ap;
        register gid_t *gp;
        register int *lp;
        int groups[NGROUPS];

        for (gp = &u.u_groups[NGROUPS]; gp > u.u_groups; gp--)
                if (gp[-1] != NOGROUP)
                        break;
        if (uap->gidsetsize < gp - u.u_groups) {
                u.u_error = EINVAL;
                return;
        }
        uap->gidsetsize = gp - u.u_groups;
        for (lp = groups, gp = u.u_groups; lp < &groups[uap->gidsetsize]; )
                *lp++ = *gp++;
        u.u_error = copyout((caddr_t)groups, (caddr_t)uap->gidset,
            uap->gidsetsize * sizeof (groups[0]));
        if (u.u_error)
                return;
        u.u_r.r_val1 = uap->gidsetsize;
}

setsid()
{
        register struct proc *p = u.u_procp;

        if ((p->p_pgid == p->p_pid) || pgfind(p->p_pid))
                u.u_error = EPERM;
        else {
                pgmv(p, p->p_pid, 1);
                u.u_r.r_val1 = p->p_pid;
        }
        return;
}

/*
 * set process group
 *
 * if target pid != caller's pid
 *      pid must be an inferior
 *      pid must be in same session
 *      pid can't have done an exec
 *      there must exist a pid with pgid in same session
 * pid must not be session leader
 */
setpgrp()
{
        register struct a {
                int     pid;
                int     pgid;
        } *uap = (struct a *)u.u_ap;
        register struct proc *p;
        register struct pgrp *pgrp;

        if (uap->pid == 0)
                p = u.u_procp;
        else if ((p = pfind(uap->pid)) == 0 || !inferior(p)) {
                u.u_error = ESRCH;
                return;
        }
        else if (p != u.u_procp) {
                if (p->p_session != u.u_procp->p_session) {
                        u.u_error = EPERM;
                        return;
                }
                if (p->p_flag&SEXEC) {
                        u.u_error = EACCES;
                        return;
                }
        }
        if (SESS_LEADER(p)) {
                u.u_error = EPERM;
                return;
        }
        if (uap->pgid == 0)
                uap->pgid = p->p_pid;
        else if ((uap->pgid != p->p_pid) &&
                (((pgrp = pgfind(uap->pgid)) == 0) ||
                   pgrp->pg_mem == NULL ||
                   pgrp->pg_session != u.u_procp->p_session)) {
                u.u_error = EPERM;
                return;
        }
        /*
         * done checking, now doit
         */
        pgmv(p, uap->pgid, 0);
}

setreuid()
{
        struct a {
                int     ruid;
                int     euid;
        } *uap;
        register int ruid, euid;

        uap = (struct a *)u.u_ap;
        ruid = uap->ruid;
        if (ruid == -1)
                ruid = u.u_ruid;
        if (u.u_ruid != ruid && u.u_uid != ruid && !suser())
                return;
        euid = uap->euid;
        if (euid == -1)
                euid = u.u_uid;
        if (u.u_ruid != euid && u.u_uid != euid && !suser())
                return;
        /*
         * Everything's okay, do it.
         */
#ifdef QUOTA
        if (u.u_quota->q_uid != ruid) {
                qclean();
                qstart(getquota((uid_t)ruid, 0, 0));
        }
#endif
        u.u_procp->p_uid = euid;
        u.u_ruid = ruid;
        u.u_uid = euid;
}

setregid()
{
        register struct a {
                int     rgid;
                int     egid;
        } *uap;
        register int rgid, egid;

        uap = (struct a *)u.u_ap;
        rgid = uap->rgid;
        if (rgid == -1)
                rgid = u.u_rgid;
        if (u.u_rgid != rgid && u.u_gid != rgid && !suser())
                return;
        egid = uap->egid;
        if (egid == -1)
                egid = u.u_gid;
        if (u.u_rgid != egid && u.u_gid != egid && !suser())
                return;
        if (u.u_rgid != rgid) {
                leavegroup(u.u_rgid);
                (void) entergroup((gid_t)rgid);
                u.u_rgid = rgid;
        }
        u.u_gid = egid;
}

setgroups()
{
        register struct a {
                u_int   gidsetsize;
                int     *gidset;
        } *uap = (struct a *)u.u_ap;
        register gid_t *gp;
        register int *lp;
        int groups[NGROUPS];

        if (!suser())
                return;
        if (uap->gidsetsize > sizeof (u.u_groups) / sizeof (u.u_groups[0])) {
                u.u_error = EINVAL;
                return;
        }
        u.u_error = copyin((caddr_t)uap->gidset, (caddr_t)groups,
            uap->gidsetsize * sizeof (groups[0]));
        if (u.u_error)
                return;
        for (lp = groups, gp = u.u_groups; lp < &groups[uap->gidsetsize]; )
                *gp++ = *lp++;
        for ( ; gp < &u.u_groups[NGROUPS]; gp++)
                *gp = NOGROUP;
}

/*
 * Group utility functions.
 */

/*
 * Delete gid from the group set.
 */
leavegroup(gid)
        gid_t gid;
{
        register gid_t *gp;

        for (gp = u.u_groups; gp < &u.u_groups[NGROUPS]; gp++)
                if (*gp == gid)
                        goto found;
        return;
found:
        for (; gp < &u.u_groups[NGROUPS-1]; gp++)
                *gp = *(gp+1);
        *gp = NOGROUP;
}

/*
 * Add gid to the group set.
 */
entergroup(gid)
        gid_t gid;
{
        register gid_t *gp;

        for (gp = u.u_groups; gp < &u.u_groups[NGROUPS]; gp++) {
                if (*gp == gid)
                        return (0);
                if (*gp == NOGROUP) {
                        *gp = gid;
                        return (0);
                }
        }
        return (-1);
}

/*
 * Check if gid is a member of the group set.
 */
groupmember(gid)
        gid_t gid;
{
        register gid_t *gp;

        if (u.u_gid == gid)
                return (1);
        for (gp = u.u_groups; gp < &u.u_groups[NGROUPS] && *gp != NOGROUP; gp++)
                if (*gp == gid)
                        return (1);
        return (0);
}