/*      $NetBSD: procfs_limit.c,v 1.5 2024/05/12 17:22:29 christos Exp $        */

/*-
 * Copyright (c) 2019 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: procfs_limit.c,v 1.5 2024/05/12 17:22:29 christos Exp $");

#if defined(_KERNEL_OPT)
#include "opt_sysv.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/resource.h>
#include <miscfs/procfs/procfs.h>
#include <compat/linux/common/linux_misc.h>
#ifdef SYSVMSG
#include <sys/msg.h>
#endif

/* Taken from FreeBSD sys/compat/linprocfs/linprocfs.c */
static const struct linux_rlimit_ident {
        const char      *desc;
        const char      *unit;
        unsigned int    rlim_id;
} linux_rlimits_ident[] = {
        { "Max cpu time",       "seconds",      RLIMIT_CPU },
        { "Max file size",      "bytes",        RLIMIT_FSIZE },
        { "Max data size",      "bytes",        RLIMIT_DATA },
        { "Max stack size",     "bytes",        RLIMIT_STACK },
        { "Max core file size", "bytes",        RLIMIT_CORE },
        { "Max resident set",   "bytes",        RLIMIT_RSS },
        { "Max processes",      "processes",    RLIMIT_NPROC },
        { "Max open files",     "files",        RLIMIT_NOFILE },
        { "Max locked memory",  "bytes",        RLIMIT_MEMLOCK },
        { "Max address space",  "bytes",        RLIMIT_AS },
        { "Max file locks",     "locks",        LINUX_RLIMIT_LOCKS },
        { "Max pending signals", "signals",     LINUX_RLIMIT_SIGPENDING },
        { "Max msgqueue size",  "bytes",        LINUX_RLIMIT_MSGQUEUE },
        { "Max nice priority",  "",             LINUX_RLIMIT_NICE },
        { "Max realtime priority", "",          LINUX_RLIMIT_RTPRIO },
        { "Max realtime timeout", "us",         LINUX_RLIMIT_RTTIME },
        { 0, 0, 0 }
};

static size_t
prl(char *buf, size_t len, intmax_t lim, char sep)
{
        if (lim == RLIM_INFINITY)
                return snprintf(buf, len, "%#20jx%c", lim, sep);
        else
                return snprintf(buf, len, "%20jd%c", lim, sep);
}

int
procfs_dolimit(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
     struct uio *uio)
{
        static const char *label[] = RLIM_STRINGS;
        int error;
        char *buffer;
        size_t bufsize, pos, i;
        struct rlimit rl[RLIM_NLIMITS];

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

        mutex_enter(&proc_lock);
        mutex_enter(p->p_lock);
        memcpy(rl, p->p_rlimit, sizeof(rl));
        mutex_exit(p->p_lock);
        mutex_exit(&proc_lock);

        error = 0;

        bufsize = (64 * 3) * __arraycount(rl);
        buffer = malloc(bufsize, M_TEMP, M_WAITOK);
        pos = 0;
        for (i = 0; i < __arraycount(rl); i++) {
                pos += snprintf(buffer + pos, bufsize - pos, "%20.20s ",
                    label[i]);
                pos += prl(buffer + pos, bufsize - pos, rl[i].rlim_cur, ' ');
                pos += prl(buffer + pos, bufsize - pos, rl[i].rlim_max, '\n');
        }

        if ((uintmax_t)uio->uio_offset < pos)
                error = uiomove(buffer + uio->uio_offset,
                    pos - uio->uio_offset, uio);
        else
                error = 0;

        if (buffer != NULL)
                free(buffer, M_TEMP);

        return error;
}

int
procfs_dolimits(struct lwp *curl, struct proc *p, struct pfsnode *pfs,
     struct uio *uio)
{
        const struct linux_rlimit_ident *li;
        int error;
        char *buffer;
        size_t bufsize, pos;
        struct rlimit rl, rlimits[RLIM_NLIMITS];

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

        mutex_enter(&proc_lock);
        mutex_enter(p->p_lock);
        memcpy(rlimits, p->p_rlimit, sizeof(rlimits));
        mutex_exit(p->p_lock);
        mutex_exit(&proc_lock);

        error = 0;

        bufsize = (64 * 3) * __arraycount(linux_rlimits_ident);
        buffer = malloc(bufsize, M_TEMP, M_WAITOK);
        pos = snprintf(buffer, bufsize, "%-26s%-21s%-21s%-21s\n",
            "Limit", "Soft Limit", "Hard Limit", "Units");
        for (li = linux_rlimits_ident; li->desc != NULL; ++li) {
                switch (li->rlim_id)
                {
                case LINUX_RLIMIT_LOCKS:
                case LINUX_RLIMIT_RTTIME:
                case LINUX_RLIMIT_SIGPENDING:
                        rl.rlim_cur = RLIM_INFINITY;
                        break;
                case LINUX_RLIMIT_MSGQUEUE:
#ifdef SYSVMSG
                        rl.rlim_cur = rl.rlim_max = msginfo.msgmnb;
                        break;
#endif
                case LINUX_RLIMIT_NICE:
                case LINUX_RLIMIT_RTPRIO:
                        rl.rlim_cur = rl.rlim_max = 0;
                        break;
                default:
                        rl = rlimits[li->rlim_id];
                        break;
                }
                if (rl.rlim_cur == RLIM_INFINITY)
                        pos += snprintf(buffer + pos, bufsize - pos,
                            "%-26s%-21s%-21s%-10s\n",
                            li->desc, "unlimited", "unlimited", li->unit);
                else
                        pos += snprintf(buffer + pos, bufsize - pos,
                            "%-26s%-21llu%-21llu%-10s\n",
                            li->desc, (unsigned long long)rl.rlim_cur,
                            (unsigned long long)rl.rlim_max, li->unit);
        }

        if ((uintmax_t)uio->uio_offset < pos)
                error = uiomove(buffer + uio->uio_offset,
                    pos - uio->uio_offset, uio);
        else
                error = 0;

        if (buffer != NULL)
                free(buffer, M_TEMP);

        return error;
}