/* $NetBSD: db_variables.c,v 1.47 2020/03/10 15:58:37 christos Exp $ */

/* $NetBSD: db_variables.c,v 1.47 2020/03/10 15:58:37 christos Exp $ */

/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or [email protected]
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_variables.c,v 1.47 2020/03/10 15:58:37 christos Exp $");

#ifdef _KERNEL_OPT
#include "opt_ddbparam.h"
#endif

#include <sys/param.h>
#include <sys/proc.h>
#include <uvm/uvm_extern.h>
#include <sys/sysctl.h>

#include <ddb/ddb.h>
#include <ddb/ddbvar.h>

/*
* If this is non-zero, the DDB will be entered when the system
* panics. Initialize it so that it's patchable.
*/
#ifndef DDB_ONPANIC
#define DDB_ONPANIC 1
#endif
int db_onpanic = DDB_ONPANIC;

/*
* Can DDB can be entered from the console?
*/
#ifndef DDB_FROMCONSOLE
#define DDB_FROMCONSOLE 1
#endif
int db_fromconsole = DDB_FROMCONSOLE;

/*
* Output DDB output to the message buffer?
*/
#ifndef DDB_TEE_MSGBUF
#define DDB_TEE_MSGBUF 0
#endif
int db_tee_msgbuf = DDB_TEE_MSGBUF;

#ifndef DDB_PANICSTACKFRAMES
#define DDB_PANICSTACKFRAMES 65535
#endif
int db_panicstackframes = DDB_PANICSTACKFRAMES;

#ifndef DDB_DUMPSTACK
#define DDB_DUMPSTACK 1
#endif
int db_dumpstack = DDB_DUMPSTACK;

static int db_rw_internal_variable(const struct db_variable *, db_expr_t *,
int);
static int db_find_variable(const struct db_variable **);

/* XXX must all be ints for sysctl. */
const struct db_variable db_vars[] = {
{
.name = "fromconsole",
.valuep = &db_fromconsole,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "maxoff",
.valuep = &db_maxoff,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "maxwidth",
.valuep = &db_max_width,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "lines",
.valuep = &db_max_line,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "onpanic",
.valuep = &db_onpanic,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "panicstackframes",
.valuep = &db_panicstackframes,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "dumpstack",
.valuep = &db_dumpstack,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "radix",
.valuep = &db_radix,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "tabstops",
.valuep = &db_tab_stop_width,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
{
.name = "tee_msgbuf",
.valuep = &db_tee_msgbuf,
.fcn = db_rw_internal_variable,
.modif = NULL,
},
};
const struct db_variable * const db_evars = db_vars + __arraycount(db_vars);

/*
* ddb command line access to the DDB variables defined above.
*/
static int
db_rw_internal_variable(const struct db_variable *vp, db_expr_t *valp, int rw)
{

if (rw == DB_VAR_GET)
*valp = *(int *)vp->valuep;
else
*(int *)vp->valuep = *valp;
return (0);
}

/*
* sysctl(3) access to the DDB variables defined above.
*/
#ifdef _KERNEL
SYSCTL_SETUP(sysctl_ddb_setup, "sysctl ddb subtree setup")
{

sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "radix",
SYSCTL_DESCR("Input and output radix"),
NULL, 0, &db_radix, 0,
CTL_DDB, DDBCTL_RADIX, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maxoff",
SYSCTL_DESCR("Maximum symbol offset"),
NULL, 0, &db_maxoff, 0,
CTL_DDB, DDBCTL_MAXOFF, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maxwidth",
SYSCTL_DESCR("Maximum output line width"),
NULL, 0, &db_max_width, 0,
CTL_DDB, DDBCTL_MAXWIDTH, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "lines",
SYSCTL_DESCR("Number of display lines"),
NULL, 0, &db_max_line, 0,
CTL_DDB, DDBCTL_LINES, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "tabstops",
SYSCTL_DESCR("Output tab width"),
NULL, 0, &db_tab_stop_width, 0,
CTL_DDB, DDBCTL_TABSTOPS, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "onpanic",
SYSCTL_DESCR("Whether to enter ddb on a kernel panic"),
NULL, 0, &db_onpanic, 0,
CTL_DDB, DDBCTL_ONPANIC, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "fromconsole",
SYSCTL_DESCR("Whether ddb can be entered from the "
"console"),
NULL, 0, &db_fromconsole, 0,
CTL_DDB, DDBCTL_FROMCONSOLE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "tee_msgbuf",
SYSCTL_DESCR("Whether to tee ddb output to the msgbuf"),
NULL, 0, &db_tee_msgbuf, 0,
CTL_DDB, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_STRING, "commandonenter",
SYSCTL_DESCR("Command to be executed on each ddb enter"),
NULL, 0, db_cmd_on_enter, DB_LINE_MAXLEN,
CTL_DDB, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "panicstackframes",
SYSCTL_DESCR("Number of stack frames to print on panic"),
NULL, 0, &db_panicstackframes, 0,
CTL_DDB, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "dumpstack",
SYSCTL_DESCR("On panic print stack trace"),
NULL, 0, &db_dumpstack, 0,
CTL_DDB, CTL_CREATE, CTL_EOL);
}
#endif /* _KERNEL */

int
db_find_variable(const struct db_variable **varp)
{
int t;
const struct db_variable *vp;

t = db_read_token();
if (t == tIDENT) {
for (vp = db_vars; vp < db_evars; vp++) {
if (!strcmp(db_tok_string, vp->name)) {
*varp = vp;
return (1);
}
}
#ifdef _KERNEL
for (vp = db_regs; vp < db_eregs; vp++) {
if (!strcmp(db_tok_string, vp->name)) {
*varp = vp;
return (1);
}
}
#endif
}
db_error("Unknown variable\n");
/*NOTREACHED*/
return 0;
}

int
db_get_variable(db_expr_t *valuep)
{
const struct db_variable *vp;

if (!db_find_variable(&vp))
return (0);

db_read_variable(vp, valuep);

return (1);
}

int
db_set_variable(db_expr_t value)
{
const struct db_variable *vp;

if (!db_find_variable(&vp))
return (0);

db_write_variable(vp, &value);

return (1);
}

void
db_read_variable(const struct db_variable *vp, db_expr_t *valuep)
{
int (*func)(const struct db_variable *, db_expr_t *, int) = vp->fcn;

if (func == FCN_NULL)
*valuep = *(db_expr_t *)vp->valuep;
else
(*func)(vp, valuep, DB_VAR_GET);
}

void
db_write_variable(const struct db_variable *vp, db_expr_t *valuep)
{
int (*func)(const struct db_variable *, db_expr_t *, int) = vp->fcn;

if (func == FCN_NULL)
*(db_expr_t *)vp->valuep = *valuep;
else
(*func)(vp, valuep, DB_VAR_SET);
}

/*ARGSUSED*/
void
db_set_cmd(db_expr_t addr, bool have_addr,
db_expr_t count, const char *modif)
{
db_expr_t value;
db_expr_t old_value;
const struct db_variable *vp = NULL; /* XXX: GCC */
int t;

t = db_read_token();
if (t != tDOLLAR) {
db_error("Unknown variable\n");
/*NOTREACHED*/
}
if (!db_find_variable(&vp)) {
db_error("Unknown variable\n");
/*NOTREACHED*/
}

t = db_read_token();
if (t != tEQ)
db_unread_token(t);

if (!db_expression(&value)) {
db_error("No value\n");
/*NOTREACHED*/
}
if (db_read_token() != tEOL) {
db_error("?\n");
/*NOTREACHED*/
}

db_read_variable(vp, &old_value);
db_printf("$%s\t\t%s = ", vp->name, db_num_to_str(old_value));
db_printf("%s\n", db_num_to_str(value));
db_write_variable(vp, &value);
}