sys/ddb/db_sysctl.c

   1
   2 /*
   3  * db_sysctl.c
   4  *
   5  * Copyright (c) 2000 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Archie Cobbs <archie@whistle.com>
  38  *
  39  * $FreeBSD: src/sys/ddb/db_sysctl.c,v 1.1.4.1 2000/08/03 00:09:27 ps Exp $
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/kernel.h>
  45 #include <sys/sysctl.h>
  46 #include <sys/reboot.h>
  47
  48 #define DESCRIPTION     "Set to `ddb' or `gdb' to enter the kernel debugger"
  49 #define READ_MODE       ""
  50 #define MODE_DDB        "ddb"
  51 #define MODE_GDB        "gdb"
  52
  53 /*
  54  * This sysctl forces the kernel to enter the debugger.
  55  */
  56 static int
  57 sysctl_debug_enter_debugger(SYSCTL_HANDLER_ARGS)
  58 {
  59         char dmode[64];
  60         int error;
  61
  62         strncpy(dmode, READ_MODE, sizeof(dmode) - 1);
  63         dmode[sizeof(dmode) - 1] = '\0';
  64         error = sysctl_handle_string(oidp, &dmode[0], sizeof(dmode), req);
  65
  66         if (error == 0 && req->newptr != NULL) {
  67                 if (strcmp(dmode, MODE_DDB) == 0)
  68                         boothowto &= ~RB_GDB;
  69                 else if (strcmp(dmode, MODE_GDB) == 0)
  70                         boothowto |= RB_GDB;
  71                 else
  72                         return EINVAL;
  73                 Debugger("debug.enter_debugger");
  74         }
  75         return error;
  76 }
  77 SYSCTL_PROC(_debug, OID_AUTO, enter_debugger, CTLTYPE_STRING | CTLFLAG_RW,
  78     0, 0, sysctl_debug_enter_debugger, "A", DESCRIPTION);
  79
  80 /*
  81  * This sysctl forces a kernel panic.
  82  */
  83 static int
  84 sysctl_debug_panic(SYSCTL_HANDLER_ARGS)
  85 {
  86         int err;
  87         int val = 0;
  88
  89         err = sysctl_handle_int(oidp, &val, 0, req);
  90         if (val == 1)
  91                 panic("sysctl_debug_panic");
  92         return err;
  93 }
  94 SYSCTL_PROC(_debug, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
  95             sysctl_debug_panic, "I", "Set to panic the system");
  96
  97 /*
  98  * This sysctl forces a kernel stack guard panic.  If you don't get
  99  * a nice clean page-fault guard panic message then the guard isn't
 100  * working.
 101  */
 102 static void
 103 stack_guard_panic2(void)
 104 {
 105         volatile char dummy[128];
 106
 107         stack_guard_panic2();
 108         /* NOT REACHED */
 109         kprintf("%p", dummy);   /* dummy to force dummy[] to be allocated */
 110 }
 111
 112 static int
 113 sysctl_debug_panic2(SYSCTL_HANDLER_ARGS)
 114 {
 115         int err;
 116         int val = 0;
 117
 118         err = sysctl_handle_int(oidp, &val, 0, req);
 119         if (val == 1)
 120                 stack_guard_panic2();
 121         return err;
 122 }
 123 SYSCTL_PROC(_debug, OID_AUTO, panic2, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
 124             sysctl_debug_panic2, "I", "Set to panic the system w/stack guard");