/*      $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  Software.Distribution@CS.CMU.EDU
 *  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);
}