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

#include <sys/types.h>
#include <sys/sysmacros.h>

#include <ucontext.h>
#include <strings.h>
#include <stdio.h>
#include <errno.h>

#include <fmd_trace.h>
#include <fmd_alloc.h>
#include <fmd_subr.h>
#include <fmd_conf.h>
#include <fmd.h>

fmd_tracebuf_t *
fmd_trace_create(void)
{
        fmd_tracebuf_t *tbp = fmd_zalloc(sizeof (fmd_tracebuf_t), FMD_SLEEP);
        size_t bufsize;

        (void) fmd_conf_getprop(fmd.d_conf, "trace.frames", &tbp->tb_frames);
        (void) fmd_conf_getprop(fmd.d_conf, "trace.recs", &tbp->tb_recs);

        /*
         * We require 8-byte alignment of fmd_tracerec_t to store hrtime_t's.
         * Since the trailing flexible array member is of type uintptr_t, we
         * may need to allocate an additional element if we are compiling
         * 32-bit; otherwise uintptr_t is 8 bytes so any value of tb_frames is
         * acceptable.
         *
         * tb_frames includes the first element, whose size is reflected in
         * sizeof (fmd_tracerec_t).  Therefore, if fmd_tracerec_t's size is
         * 0 mod 8, we must be sure the total number of frames is odd.
         * Otherwise, we need at least one extra frame, so the total count
         * must be even.  This will continue to work even if the sizes or
         * types of other fmd_tracerec_t members are changed.
         */
#ifdef _ILP32
        /*CONSTCOND*/
        if (sizeof (fmd_tracerec_t) % sizeof (hrtime_t) == 0)
                tbp->tb_frames = (tbp->tb_frames & ~1UL) + 1;
        else
                tbp->tb_frames = P2ROUNDUP(tbp->tb_frames, 2);
#endif
        tbp->tb_size = sizeof (fmd_tracerec_t) +
            sizeof (uintptr_t) * (MAX(tbp->tb_frames, 1) - 1);

        bufsize = tbp->tb_size * tbp->tb_recs;

        tbp->tb_buf = fmd_zalloc(bufsize, FMD_SLEEP);
        tbp->tb_end = (void *)((uintptr_t)tbp->tb_buf + bufsize - tbp->tb_size);
        tbp->tb_ptr = tbp->tb_buf;

        return (tbp);
}

void
fmd_trace_destroy(fmd_tracebuf_t *tbp)
{
        fmd_free(tbp->tb_buf, tbp->tb_size * tbp->tb_recs);
        fmd_free(tbp, sizeof (fmd_tracebuf_t));
}

/*
 * Callback for walkcontext(3C) to store the stack trace.  We use tr_tag below
 * to store the maximum value of depth that is permitted so we can use it here.
 */
/*ARGSUSED*/
static int
fmd_trace_frame(uintptr_t pc, int sig, fmd_tracerec_t *trp)
{
        trp->tr_stack[trp->tr_depth++] = pc;
        return (trp->tr_depth >= trp->tr_tag);
}

/*ARGSUSED*/
fmd_tracerec_t *
fmd_trace_none(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
{
        return (NULL);
}

fmd_tracerec_t *
fmd_trace_lite(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
{
        hrtime_t time = gethrtime();
        fmd_tracerec_t *trp = tbp->tb_ptr;
        char *p;

        if (tbp->tb_depth++ != 0) {
                tbp->tb_depth--;
                return (NULL);
        }

        trp->tr_time = time;
        trp->tr_file = NULL;
        trp->tr_line = 0;
        trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
        trp->tr_tag = fmd_ntz32(tag);

        (void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
        p = &trp->tr_msg[strlen(trp->tr_msg)];
        if (p > trp->tr_msg && p[-1] == '\n')
                p[-1] = '\0';

        if (tbp->tb_ptr != tbp->tb_end)
                tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
        else
                tbp->tb_ptr = tbp->tb_buf;

        tbp->tb_depth--;
        return (trp);
}

fmd_tracerec_t *
fmd_trace_full(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
{
        hrtime_t time = gethrtime();
        fmd_tracerec_t *trp = tbp->tb_ptr;
        ucontext_t uc;
        char *p;

        if (tbp->tb_depth++ != 0) {
                tbp->tb_depth--;
                return (NULL);
        }

        (void) getcontext(&uc);
        trp->tr_depth = 0;
        trp->tr_tag = tbp->tb_frames; /* for use by fmd_trace_frame() */
        (void) walkcontext(&uc, (int (*)())fmd_trace_frame, trp);

        trp->tr_time = time;
        trp->tr_file = NULL;
        trp->tr_line = 0;
        trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
        trp->tr_tag = fmd_ntz32(tag);

        if (fmd.d_fmd_debug & FMD_DBG_TRACE)
                fmd_vdprintf(tag, format, ap);

        (void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
        p = &trp->tr_msg[strlen(trp->tr_msg)];
        if (p > trp->tr_msg && p[-1] == '\n')
                p[-1] = '\0';

        if (tbp->tb_ptr != tbp->tb_end)
                tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
        else
                tbp->tb_ptr = tbp->tb_buf;

        tbp->tb_depth--;
        return (trp);
}