subr_stack.c

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/*-
 * Copyright (c) 2005 Antoine Brodin
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "opt_ddb.h"

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include <sys/param.h>
#include <sys/kernel.h>
#ifdef KTR
#include <sys/ktr.h>
#endif
#include <sys/linker.h>
#include <sys/malloc.h>
#include <sys/sbuf.h>
#include <sys/stack.h>
#include <sys/systm.h>
#include <sys/sysctl.h>

FEATURE(stack, "Support for capturing kernel stack");

static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");

static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
            long *offset);
static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);

struct stack *
stack_create(void)
{
        struct stack *st;

        st = malloc(sizeof *st, M_STACK, M_WAITOK | M_ZERO);
        return (st);
}

void
stack_destroy(struct stack *st)
{

        free(st, M_STACK);
}

int
stack_put(struct stack *st, vm_offset_t pc)
{

        if (st->depth < STACK_MAX) {
                st->pcs[st->depth++] = pc;
                return (0);
        } else
                return (-1);
}

void
stack_copy(struct stack *src, struct stack *dst)
{

        *dst = *src;
}

void
stack_zero(struct stack *st)
{

        bzero(st, sizeof *st);
}

void
stack_print(struct stack *st)
{
        char namebuf[64];
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                (void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
                    &offset);
                printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
                    namebuf, offset);
        }
}

void
stack_print_short(struct stack *st)
{
        char namebuf[64];
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                if (i > 0)
                        printf(" ");
                if (stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
                    &offset) == 0)
                        printf("%s+%#lx", namebuf, offset);
                else
                        printf("%p", (void *)st->pcs[i]);
        }
        printf("\n");
}

void
stack_print_ddb(struct stack *st)
{
        const char *name;
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                stack_symbol_ddb(st->pcs[i], &name, &offset);
                printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
                    name, offset);
        }
}

#ifdef DDB
void
stack_print_short_ddb(struct stack *st)
{
        const char *name;
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                if (i > 0)
                        printf(" ");
                if (stack_symbol_ddb(st->pcs[i], &name, &offset) == 0)
                        printf("%s+%#lx", name, offset);
                else
                        printf("%p", (void *)st->pcs[i]);
        }
        printf("\n");
}
#endif

/*
 * Two print routines -- one for use from DDB and DDB-like contexts, the
 * other for use in the live kernel.
 */
void
stack_sbuf_print(struct sbuf *sb, struct stack *st)
{
        char namebuf[64];
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                (void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
                    &offset);
                sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
                    namebuf, offset);
        }
}

#ifdef DDB
void
stack_sbuf_print_ddb(struct sbuf *sb, struct stack *st)
{
        const char *name;
        long offset;
        int i;

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        for (i = 0; i < st->depth; i++) {
                (void)stack_symbol_ddb(st->pcs[i], &name, &offset);
                sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
                    name, offset);
        }
}
#endif

#ifdef KTR
void
stack_ktr(u_int mask, const char *file, int line, struct stack *st, u_int depth,
    int cheap)
{
#ifdef DDB
        const char *name;
        long offset;
        int i;
#endif

        KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
        if (cheap) {
                ktr_tracepoint(mask, file, line, "#0 %p %p %p %p %p %p",
                    st->pcs[0], st->pcs[1], st->pcs[2], st->pcs[3],
                    st->pcs[4], st->pcs[5]);
                if (st->depth <= 6)
                        return;
                ktr_tracepoint(mask, file, line, "#1 %p %p %p %p %p %p",
                    st->pcs[6], st->pcs[7], st->pcs[8], st->pcs[9],
                    st->pcs[10], st->pcs[11]);
                if (st->depth <= 12)
                        return;
                ktr_tracepoint(mask, file, line, "#2 %p %p %p %p %p %p",
                    st->pcs[12], st->pcs[13], st->pcs[14], st->pcs[15],
                    st->pcs[16], st->pcs[17]);
#ifdef DDB
        } else {
                if (depth == 0 || st->depth < depth)
                        depth = st->depth;
                for (i = 0; i < depth; i++) {
                        (void)stack_symbol_ddb(st->pcs[i], &name, &offset);
                        ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
                            i, st->pcs[i], (u_long)name, offset, 0, 0);
                }
#endif
        }
}
#endif

/*
 * Two variants of stack symbol lookup -- one that uses the DDB interfaces
 * and bypasses linker locking, and the other that doesn't.
 */
static int
stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset)
{

        if (linker_search_symbol_name((caddr_t)pc, namebuf, buflen,
            offset) != 0) {
                *offset = 0;
                strlcpy(namebuf, "??", buflen);
                return (ENOENT);
        } else
                return (0);
}

static int
stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
{
        linker_symval_t symval;
        c_linker_sym_t sym;

        if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
                goto out;
        if (linker_ddb_symbol_values(sym, &symval) != 0)
                goto out;
        if (symval.name != NULL) {
                *name = symval.name;
                return (0);
        }
 out:
        *offset = 0;
        *name = "??";
        return (ENOENT);
}