/*
 * Copyright (c) 1993 Jan-Simon Pendry
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)procfs_status.c     8.4 (Berkeley) 6/15/94
 *
 * From:
 * $FreeBSD: src/sys/miscfs/procfs/procfs_status.c,v 1.20.2.4 2002/01/22 17:22:59 nectar Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/caps.h>
#include <sys/jail.h>
#include <sys/vnode.h>
#include <sys/tty.h>
#include <sys/resourcevar.h>
#include <vfs/procfs/procfs.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>
#include <sys/exec.h>

#define DOCHECK() do {  \
        if (ps >= psbuf+sizeof(psbuf)) {        \
                error = ENOMEM;                 \
                goto bailout;                   \
        }                                       \
} while (0)

int
procfs_dostatus(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
                struct uio *uio)
{
        struct proc *p = lp->lwp_proc;
        struct session *sess;
        struct tty *tp;
        struct ucred *cr;
        char *ps;
        char *sep;
        int pid, ppid, pgid, sid;
        size_t xlen;
        int i;
        int error;
        char psbuf[256];        /* XXX - conservative */

        if (uio->uio_rw != UIO_READ)
                return (EOPNOTSUPP);

        pid = p->p_pid;
        ppid = p->p_pptr ? p->p_pptr->p_pid : 0;
        pgid = p->p_pgrp->pg_id;
        sess = p->p_pgrp->pg_session;
        sid = sess->s_leader ? sess->s_leader->p_pid : 0;

/* comm pid ppid pgid sid maj,min ctty,sldr start ut st wmsg
                                euid ruid rgid,egid,groups[1 .. NGROUPS]
*/
        KASSERT(sizeof(psbuf) > MAXCOMLEN,
                ("Too short buffer for new MAXCOMLEN"));

        ps = psbuf;
        bcopy(p->p_comm, ps, MAXCOMLEN);
        ps[MAXCOMLEN] = '\0';
        ps += strlen(ps);
        DOCHECK();
        ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
            " %d %d %d %d ", pid, ppid, pgid, sid);
        DOCHECK();
        if ((p->p_flags & P_CONTROLT) && (tp = sess->s_ttyp))
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
                    "%d,%d ", major(tp->t_dev), minor(tp->t_dev));
        else
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
                    "%d,%d ", -1, -1);
        DOCHECK();

        sep = "";
        if (sess->s_ttyvp) {
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, "%sctty", sep);
                sep = ",";
                DOCHECK();
        }
        if (SESS_LEADER(p)) {
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, "%ssldr", sep);
                sep = ",";
                DOCHECK();
        }
        if (*sep != ',') {
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, "noflags");
                DOCHECK();
        }

        {
                struct rusage ru;

                calcru_proc(p, &ru);
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
                    " %ld,%ld %ld,%ld %ld,%ld",
                    p->p_start.tv_sec,
                    p->p_start.tv_usec,
                    ru.ru_utime.tv_sec, ru.ru_utime.tv_usec,
                    ru.ru_stime.tv_sec, ru.ru_stime.tv_usec);
        }
        DOCHECK();

        ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, " %s",
                (lp->lwp_wchan && lp->lwp_wmesg) ? lp->lwp_wmesg : "nochan");
        DOCHECK();

        cr = p->p_ucred;

        ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, " %lu %lu %lu",
                (u_long)cr->cr_uid,
                (u_long)p->p_ucred->cr_ruid,
                (u_long)p->p_ucred->cr_rgid);
        DOCHECK();

        /* egid (p->p_ucred->cr_svgid) is equal to cr_ngroups[0]
           see also getegid(2) in /sys/kern/kern_prot.c */

        for (i = 0; i < cr->cr_ngroups; i++) {
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
                    ",%lu", (u_long)cr->cr_groups[i]);
                DOCHECK();
        }

        if (p->p_ucred->cr_prison)
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps,
                    " %s", p->p_ucred->cr_prison->pr_host);
        else
                ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, " -");
        DOCHECK();
        ps += ksnprintf(ps, psbuf + sizeof(psbuf) - ps, "\n");
        DOCHECK();

        xlen = ps - psbuf;
        error = uiomove_frombuf(psbuf, xlen, uio);

bailout:
        return (error);
}

int
procfs_docmdline(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
                 struct uio *uio)
{
        struct proc *p = lp->lwp_proc;
        char *ps;
        int error;
        char *buf, *bp;
        struct ps_strings pstr;
        char **ps_argvstr;
        int i;
        size_t bytes_left, done;
        size_t buflen;

        if (uio->uio_rw != UIO_READ)
                return (EOPNOTSUPP);

        /*
         * If we are using the ps/cmdline caching, use that.  Otherwise
         * revert back to the old way which only implements full cmdline
         * for the current process and just p->p_comm for all other
         * processes.
         * Note that if the argv is no longer available, we deliberately
         * don't fall back on p->p_comm or return an error: the authentic
         * Linux behaviour is to return zero-length in this case.
         */
        if (lp->lwp_lpmap != NULL && lp->lwp_lpmap->thread_title[0] &&
            (ps_argsopen || (CHECKIO(curp, p) &&
                             (p->p_flags & P_INEXEC) == 0 &&
                             !p_trespass(curp->p_ucred, p->p_ucred))
            )) {
                /*
                 * Args set via writable thread mmap.
                 *
                 * We must calculate the string length manually
                 * because the user data can change at any time.
                 */
                bp = lp->lwp_lpmap->thread_title;
                for (buflen = 0; buflen < UPMAP_MAXPROCTITLE - 1; ++buflen) {
                        if (bp[buflen] == 0)
                                break;
                }
                buf = NULL;
        } else if (p->p_upmap != NULL && p->p_upmap->proc_title[0] &&
                   (ps_argsopen || (CHECKIO(curp, p) &&
                                    (p->p_flags & P_INEXEC) == 0 &&
                                    !p_trespass(curp->p_ucred, p->p_ucred))
            )) {
                /*
                 * Args set via writable user process mmap.
                 *
                 * We must calculate the string length manually
                 * because the user data can change at any time.
                 */
                bp = p->p_upmap->proc_title;
                for (buflen = 0; buflen < UPMAP_MAXPROCTITLE - 1; ++buflen) {
                        if (bp[buflen] == 0)
                                break;
                }
                buf = NULL;
        } else if (p->p_args &&
                   (ps_argsopen || (CHECKIO(curp, p) &&
                                    (p->p_flags & P_INEXEC) == 0 &&
                                    !p_trespass(curp->p_ucred, p->p_ucred))
                   )) {
                bp = p->p_args->ar_args;
                buflen = p->p_args->ar_length;
                buf = NULL;
        } else if (p != curp) {
                bp = p->p_comm;
                buflen = MAXCOMLEN;
                buf = NULL;
        } else {
                buflen = 256;
                buf = kmalloc(buflen + 1, M_TEMP, M_WAITOK);
                bp = buf;
                ps = buf;
                error = copyin((void*)PS_STRINGS, &pstr, sizeof(pstr));

                if (error) {
                        kfree(buf, M_TEMP);
                        return (error);
                }
                if (pstr.ps_nargvstr < 0) {
                        kfree(buf, M_TEMP);
                        return (EINVAL);
                }
                if (pstr.ps_nargvstr > ARG_MAX) {
                        kfree(buf, M_TEMP);
                        return (E2BIG);
                }
                ps_argvstr = kmalloc(pstr.ps_nargvstr * sizeof(char *),
                                     M_TEMP, M_WAITOK);
                error = copyin((void *)pstr.ps_argvstr, ps_argvstr,
                               pstr.ps_nargvstr * sizeof(char *));
                if (error) {
                        kfree(ps_argvstr, M_TEMP);
                        kfree(buf, M_TEMP);
                        return (error);
                }
                bytes_left = buflen;
                for (i = 0; bytes_left && (i < pstr.ps_nargvstr); i++) {
                        error = copyinstr(ps_argvstr[i], ps,
                                          bytes_left, &done);
                        /* If too long or malformed, just truncate */
                        if (error) {
                                error = 0;
                                break;
                        }
                        ps += done;
                        bytes_left -= done;
                }
                buflen = ps - buf;
                kfree(ps_argvstr, M_TEMP);
        }

        error = uiomove_frombuf(bp, buflen, uio);
        if (buf)
                kfree(buf, M_TEMP);
        return (error);
}