/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1994 SigmaSoft, Th. Lockert <tholo@sigmasoft.com>
 * All rights reserved.
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
 *
 * The split of ipcs.c into ipcs.c and ipc.c to accommodate the
 * changes in ipcrm.c was done by Edwin Groothuis <edwin@FreeBSD.org>
 */

#include <sys/types.h>
#include <sys/sysctl.h>
#define _WANT_SYSVMSG_INTERNALS
#include <sys/msg.h>
#define _WANT_SYSVSEM_INTERNALS
#include <sys/sem.h>
#define _WANT_SYSVSHM_INTERNALS
#include <sys/shm.h>

#include <assert.h>
#include <err.h>
#include <kvm.h>
#include <nlist.h>
#include <stddef.h>

#include "ipc.h"

int     use_sysctl = 1;
struct semid_kernel     *sema;
struct seminfo          seminfo;
struct msginfo          msginfo;
struct msqid_kernel     *msqids;
struct shminfo          shminfo;
struct shmid_kernel     *shmsegs;

struct nlist symbols[] = {
        { .n_name = "sema" },
        { .n_name = "seminfo" },
        { .n_name = "msginfo" },
        { .n_name = "msqids" },
        { .n_name = "shminfo" },
        { .n_name = "shmsegs" },
        { .n_name = NULL }
};

#define SHMINFO_XVEC    X(shmmax, sizeof(u_long))                       \
                        X(shmmin, sizeof(u_long))                       \
                        X(shmmni, sizeof(u_long))                       \
                        X(shmseg, sizeof(u_long))                       \
                        X(shmall, sizeof(u_long))

#define SEMINFO_XVEC    X(semmni, sizeof(int))                          \
                        X(semmns, sizeof(int))                          \
                        X(semmnu, sizeof(int))                          \
                        X(semmsl, sizeof(int))                          \
                        X(semopm, sizeof(int))                          \
                        X(semume, sizeof(int))                          \
                        X(semusz, sizeof(int))                          \
                        X(semvmx, sizeof(int))                          \
                        X(semaem, sizeof(int))

#define MSGINFO_XVEC    X(msgmax, sizeof(int))                          \
                        X(msgmni, sizeof(int))                          \
                        X(msgmnb, sizeof(int))                          \
                        X(msgtql, sizeof(int))                          \
                        X(msgssz, sizeof(int))                          \
                        X(msgseg, sizeof(int))

#define X(a, b) { "kern.ipc." #a, offsetof(TYPEC, a), (b) },
#define TYPEC   struct shminfo
static struct scgs_vector shminfo_scgsv[] = { SHMINFO_XVEC { .sysctl=NULL } };
#undef  TYPEC
#define TYPEC   struct seminfo
static struct scgs_vector seminfo_scgsv[] = { SEMINFO_XVEC { .sysctl=NULL } };
#undef  TYPEC
#define TYPEC   struct msginfo
static struct scgs_vector msginfo_scgsv[] = { MSGINFO_XVEC { .sysctl=NULL } };
#undef  TYPEC
#undef  X

kvm_t *kd;

void
sysctlgatherstruct(void *addr, size_t size, struct scgs_vector *vecarr)
{
        struct scgs_vector *xp;
        size_t tsiz;
        int rv;

        for (xp = vecarr; xp->sysctl != NULL; xp++) {
                assert(xp->offset <= size);
                tsiz = xp->size;
                rv = sysctlbyname(xp->sysctl, (char *)addr + xp->offset,
                    &tsiz, NULL, 0);
                if (rv == -1)
                        err(1, "sysctlbyname: %s", xp->sysctl);
                if (tsiz != xp->size)
                        errx(1, "%s size mismatch (expected %zu, got %zu)",
                            xp->sysctl, xp->size, tsiz);
        }
}

void
kget(int idx, void *addr, size_t size)
{
        const char *symn;               /* symbol name */
        size_t tsiz;
        int rv;
        unsigned long kaddr;
        const char *sym2sysctl[] = {    /* symbol to sysctl name table */
                "kern.ipc.sema",
                "kern.ipc.seminfo",
                "kern.ipc.msginfo",
                "kern.ipc.msqids",
                "kern.ipc.shminfo",
                "kern.ipc.shmsegs" };

        assert((unsigned)idx <= sizeof(sym2sysctl) / sizeof(*sym2sysctl));
        if (!use_sysctl) {
                symn = symbols[idx].n_name;
                if (*symn == '_')
                        symn++;
                if (symbols[idx].n_type == 0 || symbols[idx].n_value == 0)
                        errx(1, "symbol %s undefined", symn);
                /*
                 * For some symbols, the value we retrieve is
                 * actually a pointer; since we want the actual value,
                 * we have to manually dereference it.
                 */
                switch (idx) {
                case X_MSQIDS:
                        tsiz = sizeof(msqids);
                        rv = kvm_read(kd, symbols[idx].n_value,
                            &msqids, tsiz);
                        kaddr = (u_long)msqids;
                        break;
                case X_SHMSEGS:
                        tsiz = sizeof(shmsegs);
                        rv = kvm_read(kd, symbols[idx].n_value,
                            &shmsegs, tsiz);
                        kaddr = (u_long)shmsegs;
                        break;
                case X_SEMA:
                        tsiz = sizeof(sema);
                        rv = kvm_read(kd, symbols[idx].n_value,
                            &sema, tsiz);
                        kaddr = (u_long)sema;
                        break;
                default:
                        rv = tsiz = 0;
                        kaddr = symbols[idx].n_value;
                        break;
                }
                if ((unsigned)rv != tsiz)
                        errx(1, "%s: %s", symn, kvm_geterr(kd));
                if ((unsigned)kvm_read(kd, kaddr, addr, size) != size)
                        errx(1, "%s: %s", symn, kvm_geterr(kd));
        } else {
                switch (idx) {
                case X_SHMINFO:
                        sysctlgatherstruct(addr, size, shminfo_scgsv);
                        break;
                case X_SEMINFO:
                        sysctlgatherstruct(addr, size, seminfo_scgsv);
                        break;
                case X_MSGINFO:
                        sysctlgatherstruct(addr, size, msginfo_scgsv);
                        break;
                default:
                        tsiz = size;
                        rv = sysctlbyname(sym2sysctl[idx], addr, &tsiz,
                            NULL, 0);
                        if (rv == -1)
                                err(1, "sysctlbyname: %s", sym2sysctl[idx]);
                        if (tsiz != size)
                                errx(1, "%s size mismatch "
                                    "(expected %zu, got %zu)",
                                    sym2sysctl[idx], size, tsiz);
                        break;
                }
        }
}