/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
 */

/*
 * System calls for creating and inquiring about tasks and projects
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/thread.h>
#include <sys/proc.h>
#include <sys/task.h>
#include <sys/systm.h>
#include <sys/project.h>
#include <sys/cpuvar.h>
#include <sys/policy.h>
#include <sys/zone.h>
#include <sys/rctl.h>

/*
 * Limit projlist to 256k projects.
 */
#define MAX_PROJLIST_BUFSIZE            1048576

typedef struct projlist_walk {
        projid_t        *pw_buf;
        size_t          pw_bufsz;
} projlist_walk_t;

/*
 * taskid_t tasksys_settaskid(projid_t projid, uint_t flags);
 *
 * Overview
 *   Place the calling process in a new task if sufficiently privileged.  If the
 *   present task is finalized, the process may not create a new task.
 *
 * Return values
 *   0 on success, errno on failure.
 */
static long
tasksys_settaskid(projid_t projid, uint_t flags)
{
        proc_t *p = ttoproc(curthread);
        kproject_t *oldpj;
        kproject_t *kpj;
        task_t *tk, *oldtk;
        rctl_entity_p_t e;
        zone_t *zone;
        int rctlfail = 0;

        if (secpolicy_tasksys(CRED()) != 0)
                return (set_errno(EPERM));

        if (projid < 0)
                return (set_errno(EINVAL));

        if (flags & ~TASK_FINAL)
                return (set_errno(EINVAL));

        mutex_enter(&pidlock);
        if (p->p_task->tk_flags & TASK_FINAL) {
                mutex_exit(&pidlock);
                return (set_errno(EACCES));
        }
        mutex_exit(&pidlock);

        /*
         * Try to stop all other lwps in the process while we're changing
         * our project.  This way, curthread doesn't need to grab its own
         * thread_lock to find its project ID (see curprojid()).  If this
         * is the /proc agent lwp, we know that the other lwps are already
         * held.  If we failed to hold all lwps, bail out and return EINTR.
         */
        if (curthread != p->p_agenttp && !holdlwps(SHOLDFORK1))
                return (set_errno(EINTR));
        /*
         * Put a hold on our new project and make sure that nobody is
         * trying to bind it to a pool while we're joining.
         */
        kpj = project_hold_by_id(projid, p->p_zone, PROJECT_HOLD_INSERT);
        e.rcep_p.proj = kpj;
        e.rcep_t = RCENTITY_PROJECT;

        mutex_enter(&p->p_lock);
        oldpj = p->p_task->tk_proj;
        zone = p->p_zone;

        mutex_enter(&zone->zone_nlwps_lock);
        mutex_enter(&zone->zone_mem_lock);

        if (kpj->kpj_nlwps + p->p_lwpcnt > kpj->kpj_nlwps_ctl)
                if (rctl_test_entity(rc_project_nlwps, kpj->kpj_rctls, p, &e,
                    p->p_lwpcnt, 0) & RCT_DENY)
                        rctlfail = 1;

        if (kpj->kpj_ntasks + 1 > kpj->kpj_ntasks_ctl)
                if (rctl_test_entity(rc_project_ntasks, kpj->kpj_rctls, p, &e,
                    1, 0) & RCT_DENY)
                        rctlfail = 1;

        if (kpj != proj0p && kpj->kpj_nprocs + 1 > kpj->kpj_nprocs_ctl)
                if (rctl_test_entity(rc_project_nprocs, kpj->kpj_rctls, p, &e,
                    1, 0) & RCT_DENY)
                        rctlfail = 1;

        if (kpj->kpj_data.kpd_locked_mem + p->p_locked_mem >
            kpj->kpj_data.kpd_locked_mem_ctl)
                if (rctl_test_entity(rc_project_locked_mem, kpj->kpj_rctls, p,
                    &e, p->p_locked_mem, 0) & RCT_DENY)
                        rctlfail = 1;

        mutex_enter(&(kpj->kpj_data.kpd_crypto_lock));
        if (kpj->kpj_data.kpd_crypto_mem + p->p_crypto_mem >
            kpj->kpj_data.kpd_crypto_mem_ctl)
                if (rctl_test_entity(rc_project_crypto_mem, kpj->kpj_rctls, p,
                    &e, p->p_crypto_mem, 0) & RCT_DENY)
                        rctlfail = 1;

        if (rctlfail) {
                mutex_exit(&(kpj->kpj_data.kpd_crypto_lock));
                mutex_exit(&zone->zone_mem_lock);
                mutex_exit(&zone->zone_nlwps_lock);
                if (curthread != p->p_agenttp)
                        continuelwps(p);
                mutex_exit(&p->p_lock);
                project_rele(kpj);
                return (set_errno(EAGAIN));
        }
        kpj->kpj_data.kpd_crypto_mem += p->p_crypto_mem;
        mutex_exit(&(kpj->kpj_data.kpd_crypto_lock));
        kpj->kpj_data.kpd_locked_mem += p->p_locked_mem;
        kpj->kpj_nlwps += p->p_lwpcnt;
        kpj->kpj_ntasks++;
        kpj->kpj_nprocs++;

        oldpj->kpj_data.kpd_locked_mem -= p->p_locked_mem;
        mutex_enter(&(oldpj->kpj_data.kpd_crypto_lock));
        oldpj->kpj_data.kpd_crypto_mem -= p->p_crypto_mem;
        mutex_exit(&(oldpj->kpj_data.kpd_crypto_lock));
        oldpj->kpj_nlwps -= p->p_lwpcnt;
        oldpj->kpj_nprocs--;

        mutex_exit(&zone->zone_mem_lock);
        mutex_exit(&zone->zone_nlwps_lock);
        mutex_exit(&p->p_lock);

        mutex_enter(&kpj->kpj_poolbind);
        tk = task_create(projid, curproc->p_zone);
        mutex_enter(&cpu_lock);
        /*
         * Returns with p_lock held.
         */
        oldtk = task_join(tk, flags);
        if (curthread != p->p_agenttp)
                continuelwps(p);
        mutex_exit(&p->p_lock);
        mutex_exit(&cpu_lock);
        mutex_exit(&kpj->kpj_poolbind);
        task_rele(oldtk);
        project_rele(kpj);
        return (tk->tk_tkid);
}

/*
 * taskid_t tasksys_gettaskid(void);
 *
 * Overview
 *   Return the current task ID for this process.
 *
 * Return value
 *   The ID for the task to which the current process belongs.
 */
static long
tasksys_gettaskid()
{
        long ret;
        proc_t *p = ttoproc(curthread);

        mutex_enter(&pidlock);
        ret = p->p_task->tk_tkid;
        mutex_exit(&pidlock);
        return (ret);
}

/*
 * projid_t tasksys_getprojid(void);
 *
 * Overview
 *   Return the current project ID for this process.
 *
 * Return value
 *   The ID for the project to which the current process belongs.
 */
static long
tasksys_getprojid()
{
        long ret;
        proc_t *p = ttoproc(curthread);

        mutex_enter(&pidlock);
        ret = p->p_task->tk_proj->kpj_id;
        mutex_exit(&pidlock);
        return (ret);
}

static int
tasksys_projlist_cb(kproject_t *kp, void *buf)
{
        projlist_walk_t *pw = (projlist_walk_t *)buf;

        if (pw && pw->pw_bufsz >= sizeof (projid_t)) {
                *pw->pw_buf = kp->kpj_id;
                pw->pw_buf++;
                pw->pw_bufsz -= sizeof (projid_t);
        }

        return (0);
}

/*
 * long tasksys_projlist(void *buf, size_t bufsz)
 *
 * Overview
 *   Return a buffer containing the project IDs of all currently active projects
 *   in the current zone.
 *
 * Return values
 *   The minimum size of a buffer sufficiently large to contain all of the
 *   active project IDs, or -1 if an error occurs during copyout.
 */
static long
tasksys_projlist(void *buf, size_t bufsz)
{
        long ret = 0;
        projlist_walk_t pw;
        void *kbuf;

        if (buf == NULL || bufsz == 0)
                return (project_walk_all(getzoneid(), tasksys_projlist_cb,
                    NULL));

        if (bufsz > MAX_PROJLIST_BUFSIZE)
                return (set_errno(ENOMEM));

        kbuf = pw.pw_buf = kmem_zalloc(bufsz, KM_SLEEP);
        pw.pw_bufsz = bufsz;

        ret = project_walk_all(getzoneid(), tasksys_projlist_cb, &pw);

        if (copyout(kbuf, buf, bufsz) == -1)
                ret = set_errno(EFAULT);

        kmem_free(kbuf, bufsz);
        return (ret);
}

long
tasksys(int code, projid_t projid, uint_t flags, void *projidbuf, size_t pbufsz)
{
        switch (code) {
        case 0:
                return (tasksys_settaskid(projid, flags));
        case 1:
                return (tasksys_gettaskid());
        case 2:
                return (tasksys_getprojid());
        case 3:
                return (tasksys_projlist(projidbuf, pbufsz));
        default:
                return (set_errno(EINVAL));
        }
}