freebsd-skq/sys/kern/subr_stack.c
Mark Johnston 1b9254f885 Add support for a configurable output channel to witness(4).
This is useful in environments where system configuration is performed by
automated interaction with the system console, since unexpected witness
output makes such automation difficult. With this change, the new
debug.witness.output_channel sysctl allows one to specify that witness
output is to be printed to the kernel log (using log(9)) rather than the
console.

Reviewed by:	cem, jhb
MFC after:	2 weeks
Relnotes:	yes
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D4183
2015-11-19 05:56:59 +00:00

278 lines
6.4 KiB
C

/*-
* 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("$FreeBSD$");
#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(const struct stack *src, struct stack *dst)
{
*dst = *src;
}
void
stack_zero(struct stack *st)
{
bzero(st, sizeof *st);
}
void
stack_print(const 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(const 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(const 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);
}
}
#if defined(DDB) || defined(WITNESS)
void
stack_print_short_ddb(const 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, const 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);
}
}
#if defined(DDB) || defined(WITNESS)
void
stack_sbuf_print_ddb(struct sbuf *sb, const 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, const 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);
}