/*
 * 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
 *
 * Portions Copyright 2006-2008 John Birrell jb@freebsd.org
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cpuvar.h>
#include <sys/dtrace.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/kthread.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/selinfo.h>
#include <sys/smp.h>
#include <sys/stdarg.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/uio.h>
#include <sys/unistd.h>

#include <cddl/dev/dtrace/dtrace_cddl.h>

#ifdef LINUX_SYSTRACE
#if defined(__amd64__)
#include <amd64/linux/linux.h>
#include <amd64/linux/linux_proto.h>
#include <amd64/linux/linux_syscalls.c>
#include <amd64/linux/linux_systrace_args.c>
#elif defined(__i386__)
#include <i386/linux/linux.h>
#include <i386/linux/linux_proto.h>
#include <i386/linux/linux_syscalls.c>
#include <i386/linux/linux_systrace_args.c>
#else
#error Only i386 and amd64 are supported.
#endif
#define MODNAME         "linux"
extern struct sysent linux_sysent[];
#define MAXSYSCALL      LINUX_SYS_MAXSYSCALL
#define SYSCALLNAMES    linux_syscallnames
#define SYSENT          linux_sysent
#elif defined(LINUX32_SYSTRACE)
#if defined(__amd64__)
#include <amd64/linux32/linux.h>
#include <amd64/linux32/linux32_proto.h>
#include <amd64/linux32/linux32_syscalls.c>
#include <amd64/linux32/linux32_systrace_args.c>
#else
#error Only amd64 is supported.
#endif
#define MODNAME         "linux32"
extern struct sysent linux32_sysent[];
#define MAXSYSCALL      LINUX32_SYS_MAXSYSCALL
#define SYSCALLNAMES    linux32_syscallnames
#define SYSENT          linux32_sysent
#elif defined(FREEBSD32_SYSTRACE)
/*
 * The syscall arguments are processed into a DTrace argument array
 * using a generated function. See sys/tools/syscalls/README.md.
 */
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_systrace_args.c>
extern const char *freebsd32_syscallnames[];
#define MODNAME         "freebsd32"
#define MAXSYSCALL      FREEBSD32_SYS_MAXSYSCALL
#define SYSCALLNAMES    freebsd32_syscallnames
#define SYSENT          freebsd32_sysent
#else
/*
 * The syscall arguments are processed into a DTrace argument array
 * using a generated function. See sys/tools/syscalls/README.md.
 */
#include <sys/syscall.h>
#include <kern/systrace_args.c>
#define MODNAME         "freebsd"
#define MAXSYSCALL      SYS_MAXSYSCALL
#define SYSCALLNAMES    syscallnames
#define SYSENT          sysent
#define NATIVE_ABI
#endif

#define PROVNAME        "syscall"
#define DEVNAME         "dtrace/systrace/" MODNAME

#define SYSTRACE_ARTIFICIAL_FRAMES      1

#define SYSTRACE_SHIFT                  16
#define SYSTRACE_ISENTRY(x)             ((int)(x) >> SYSTRACE_SHIFT)
#define SYSTRACE_SYSNUM(x)              ((int)(x) & ((1 << SYSTRACE_SHIFT) - 1))
#define SYSTRACE_ENTRY(id)              ((1 << SYSTRACE_SHIFT) | (id))
#define SYSTRACE_RETURN(id)             (id)

#if ((1 << SYSTRACE_SHIFT) <= MAXSYSCALL)
#error 1 << SYSTRACE_SHIFT must exceed number of system calls
#endif

static int systrace_enabled_count;

static void     systrace_load(void *);
static void     systrace_unload(void *);

static void     systrace_getargdesc(void *, dtrace_id_t, void *,
                    dtrace_argdesc_t *);
static uint64_t systrace_getargval(void *, dtrace_id_t, void *, int, int);
static void     systrace_provide(void *, dtrace_probedesc_t *);
static void     systrace_destroy(void *, dtrace_id_t, void *);
static void     systrace_enable(void *, dtrace_id_t, void *);
static void     systrace_disable(void *, dtrace_id_t, void *);

static union {
        const char      **p_constnames;
        char            **pp_syscallnames;
} uglyhack = { SYSCALLNAMES };

static dtrace_pattr_t systrace_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};

static dtrace_pops_t systrace_pops = {
        .dtps_provide =         systrace_provide,
        .dtps_provide_module =  NULL,
        .dtps_enable =          systrace_enable,
        .dtps_disable =         systrace_disable,
        .dtps_suspend =         NULL,
        .dtps_resume =          NULL,
        .dtps_getargdesc =      systrace_getargdesc,
        .dtps_getargval =       systrace_getargval,
        .dtps_usermode =        NULL,
        .dtps_destroy =         systrace_destroy
};

static dtrace_provider_id_t     systrace_id;

#ifdef NATIVE_ABI
/*
 * Probe callback function.
 *
 * Note: This function is called for _all_ syscalls, regardless of which sysent
 *       array the syscall comes from. It could be a standard syscall or a
 *       compat syscall from something like Linux.
 */
static void
systrace_probe(struct syscall_args *sa, enum systrace_probe_t type, int retval)
{
        uint64_t uargs[nitems(sa->args)];
        dtrace_id_t id;
        int n_args, sysnum;

        sysnum = sa->code;
        memset(uargs, 0, sizeof(uargs));

        if (type == SYSTRACE_ENTRY) {
                if ((id = sa->callp->sy_entry) == DTRACE_IDNONE)
                        return;

                if (sa->callp->sy_systrace_args_func != NULL)
                        /*
                         * Convert the syscall parameters using the registered
                         * function.
                         */
                        (*sa->callp->sy_systrace_args_func)(sysnum, sa->args,
                            uargs, &n_args);
                else
                        /*
                         * Use the built-in system call argument conversion
                         * function to translate the syscall structure fields
                         * into the array of 64-bit values that DTrace expects.
                         */
                        systrace_args(sysnum, sa->args, uargs, &n_args);
                /*
                 * Save probe arguments now so that we can retrieve them if
                 * the getargval method is called from further down the stack.
                 */
                curthread->t_dtrace_systrace_args = uargs;
        } else {
                if ((id = sa->callp->sy_return) == DTRACE_IDNONE)
                        return;

                curthread->t_dtrace_systrace_args = NULL;
                /* Set arg0 and arg1 as the return value of this syscall. */
                uargs[0] = uargs[1] = retval;
        }

        /* Process the probe using the converted argments. */
        dtrace_probe(id, uargs[0], uargs[1], uargs[2], uargs[3], uargs[4]);
}
#endif

static void
systrace_getargdesc(void *arg, dtrace_id_t id, void *parg,
    dtrace_argdesc_t *desc)
{
        int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

        if (SYSTRACE_ISENTRY((uintptr_t)parg))
                systrace_entry_setargdesc(sysnum, desc->dtargd_ndx,
                    desc->dtargd_native, sizeof(desc->dtargd_native));
        else
                systrace_return_setargdesc(sysnum, desc->dtargd_ndx,
                    desc->dtargd_native, sizeof(desc->dtargd_native));

        if (desc->dtargd_native[0] == '\0')
                desc->dtargd_ndx = DTRACE_ARGNONE;
}

static uint64_t
systrace_getargval(void *arg __unused, dtrace_id_t id __unused,
    void *parg __unused, int argno, int aframes __unused)
{
        uint64_t *uargs;

        uargs = curthread->t_dtrace_systrace_args;
        if (uargs == NULL)
                /* This is a return probe. */
                return (0);
        if (argno >= nitems(((struct syscall_args *)NULL)->args))
                return (0);
        return (uargs[argno]);
}

static void
systrace_provide(void *arg, dtrace_probedesc_t *desc)
{
        int i;

        if (desc != NULL)
                return;

        for (i = 0; i < MAXSYSCALL; i++) {
                if (dtrace_probe_lookup(systrace_id, MODNAME,
                    uglyhack.pp_syscallnames[i], "entry") != 0)
                        continue;

                (void)dtrace_probe_create(systrace_id, MODNAME,
                    uglyhack.pp_syscallnames[i], "entry",
                    SYSTRACE_ARTIFICIAL_FRAMES,
                    (void *)((uintptr_t)SYSTRACE_ENTRY(i)));
                (void)dtrace_probe_create(systrace_id, MODNAME,
                    uglyhack.pp_syscallnames[i], "return",
                    SYSTRACE_ARTIFICIAL_FRAMES,
                    (void *)((uintptr_t)SYSTRACE_RETURN(i)));
        }
}

static void
systrace_destroy(void *arg, dtrace_id_t id, void *parg)
{
#ifdef SYSTRACE_DEBUG
        int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

        /*
         * There's nothing to do here but assert that we have actually been
         * disabled.
         */
        if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
                ASSERT(sysent[sysnum].sy_entry == DTRACE_IDNONE);
        } else {
                ASSERT(sysent[sysnum].sy_return == DTRACE_IDNONE);
        }
#endif
}

static void
systrace_enable(void *arg, dtrace_id_t id, void *parg)
{
        int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

        SYSENT[sysnum].sy_systrace_args_func = systrace_args;

        if (SYSTRACE_ISENTRY((uintptr_t)parg))
                SYSENT[sysnum].sy_entry = id;
        else
                SYSENT[sysnum].sy_return = id;
        systrace_enabled_count++;
        if (systrace_enabled_count == 1)
                systrace_enabled = true;
}

static void
systrace_disable(void *arg, dtrace_id_t id, void *parg)
{
        int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

        SYSENT[sysnum].sy_systrace_args_func = NULL;
        SYSENT[sysnum].sy_entry = DTRACE_IDNONE;
        SYSENT[sysnum].sy_return = DTRACE_IDNONE;
        systrace_enabled_count--;
        if (systrace_enabled_count == 0)
                systrace_enabled = false;
}

static void
systrace_load(void *dummy __unused)
{

        if (dtrace_register(PROVNAME, &systrace_attr, DTRACE_PRIV_USER, NULL,
            &systrace_pops, NULL, &systrace_id) != 0)
                return;

#ifdef NATIVE_ABI
        systrace_probe_func = systrace_probe;
#endif
}

static void
systrace_unload(void *dummy __unused)
{

#ifdef NATIVE_ABI
        systrace_probe_func = NULL;
#endif

        if (dtrace_unregister(systrace_id) != 0)
                return;
}

static int
systrace_modevent(module_t mod __unused, int type, void *data __unused)
{
        int error;

        error = 0;
        switch (type) {
        case MOD_LOAD:
                break;

        case MOD_UNLOAD:
                break;

        case MOD_SHUTDOWN:
                break;

        default:
                error = EOPNOTSUPP;
                break;

        }
        return (error);
}

SYSINIT(systrace_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    systrace_load, NULL);
SYSUNINIT(systrace_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    systrace_unload, NULL);

#ifdef LINUX_SYSTRACE
DEV_MODULE(systrace_linux, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux, 1);
#ifdef __amd64__
MODULE_DEPEND(systrace_linux, linux64, 1, 1, 1);
#else
MODULE_DEPEND(systrace_linux, linux, 1, 1, 1);
#endif
MODULE_DEPEND(systrace_linux, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux, opensolaris, 1, 1, 1);
#elif defined(LINUX32_SYSTRACE)
DEV_MODULE(systrace_linux32, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux32, 1);
MODULE_DEPEND(systrace_linux32, linux, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, opensolaris, 1, 1, 1);
#elif defined(FREEBSD32_SYSTRACE)
DEV_MODULE(systrace_freebsd32, systrace_modevent, NULL);
MODULE_VERSION(systrace_freebsd32, 1);
MODULE_DEPEND(systrace_freebsd32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_freebsd32, opensolaris, 1, 1, 1);
#else
DEV_MODULE(systrace, systrace_modevent, NULL);
MODULE_VERSION(systrace, 1);
MODULE_DEPEND(systrace, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace, opensolaris, 1, 1, 1);
#endif