bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/fcntl.h>
  31 #include <sys/malloc.h>
  32 #include <sys/proc.h>
  33 #include <sys/sysctl.h>
  34 #include <sys/vnode.h>
  35 #include <sys/vm.h>
  36 #include <sys/systm.h>
  37
  38 #include <mach/mach_types.h>
  39 #include <mach/kern_return.h>
  40 #include <kern/kern_types.h>
  41 #include <vm/vm_kern.h>
  42
  43
  44 /* prototypes not exported by osfmk/console. */
  45 extern void panic_dialog_test( void );
  46 extern int  panic_dialog_set_image( const unsigned char * ptr, unsigned int size );
  47 extern void panic_dialog_get_image( unsigned char ** ptr, unsigned int * size );
  48
  49 /* make the compiler happy */
  50 static int sysctl_dopanicinfo SYSCTL_HANDLER_ARGS;
  51
  52
  53 #define PANIC_IMAGE_SIZE_LIMIT  (32 * 4096)                             /* 128K - Maximum amount of memory consumed for the panic UI */
  54 #define KERN_PANICINFO_TEST     (KERN_PANICINFO_IMAGE+2)                /* Allow the panic UI to be tested by root without causing a panic */
  55
  56 /* Local data */
  57 static int image_size_limit = PANIC_IMAGE_SIZE_LIMIT;
  58
  59 /* XXX Should be STATIC for dtrace debugging.. */
  60 static int
  61 sysctl_dopanicinfo SYSCTL_HANDLER_ARGS
  62 {
  63         __unused int cmd = oidp->oid_arg2;      /* subcommand*/
  64         int *name = arg1;               /* oid element argument vector */
  65         int namelen = arg2;             /* number of oid element arguments */
  66         user_addr_t oldp = req->oldptr; /* user buffer copy out address */
  67         size_t *oldlenp = &req->oldlen; /* user buffer copy out size */
  68         user_addr_t newp = req->newptr; /* user buffer copy in address */
  69         size_t newlen = req->newlen;    /* user buffer copy in size */
  70         int error = 0;
  71         proc_t p = current_proc();
  72
  73         vm_offset_t newimage = (vm_offset_t )NULL;
  74         kern_return_t   kret;
  75         unsigned char * prev_image_ptr;
  76         unsigned int prev_image_size;
  77
  78         /* all sysctl names at this level are terminal */
  79         if (namelen != 1)
  80                 return (ENOTDIR);               /* overloaded */
  81
  82         /* must be super user to muck with image */
  83         if ( (error = proc_suser(p)) )
  84                 return (error);
  85
  86         switch (name[0]) {
  87         default:
  88                 return (ENOTSUP);
  89
  90         case KERN_PANICINFO_TEST:
  91
  92                 panic_dialog_test();
  93                 break;
  94
  95         case KERN_PANICINFO_MAXSIZE:
  96
  97                 /* return the image size limits */
  98
  99                 newlen = 0;
 100                 newp = USER_ADDR_NULL;
 101
 102                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
 103
 104                 break;
 105
 106         case KERN_PANICINFO_IMAGE:
 107
 108                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
 109                 if ( newp != USER_ADDR_NULL ) {
 110
 111                         /* check the length of the incoming image before allocating space for it. */
 112                         if ( newlen > (size_t)image_size_limit ) {
 113                                 error = ENOMEM;
 114                                 break;
 115                         }
 116
 117                         /* allocate some kernel wired memory for the new image */
 118                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page(newlen));
 119
 120                         if (kret != KERN_SUCCESS) {
 121                                 switch (kret) {
 122                                 default:
 123                                         error = EINVAL;
 124                                         break;
 125                                 case KERN_NO_SPACE:
 126                                 case KERN_RESOURCE_SHORTAGE:
 127                                         error = ENOMEM;
 128                                         break;
 129                                 case KERN_PROTECTION_FAILURE:
 130                                         error = EPERM;
 131                                         break;
 132                                 }
 133                                 break;
 134                         }
 135
 136                         /* copy the image in from user space */
 137                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 138                                 goto errout;
 139
 140                 } else {        /* setup to make the default image active */
 141
 142                         newimage = (vm_offset_t )NULL;
 143                         newlen = 0;
 144                 }
 145
 146                 /* get the current image location and size */
 147                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 148
 149                 /* did the caller request a copy of the previous image ? */
 150                 if ( oldp != USER_ADDR_NULL ) {
 151                         if ( *oldlenp < prev_image_size ) {
 152                                 error = ERANGE;
 153                                 goto errout;
 154                         }
 155
 156                         /* copy the image to user space or zero the size if the default image is active */
 157                         if ( prev_image_ptr != NULL ) {
 158                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 159                                         goto errout;
 160
 161                                 *oldlenp = prev_image_size;
 162                         }
 163                         else /* tell the user that the default image is active */
 164                                 *oldlenp = 0;
 165                 }
 166
 167                 /* Make the new image active, or reactivate the default image.
 168                    But, handle the special case of asking for the current image
 169                    without changing the current image.
 170                 */
 171
 172                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 173                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 174                                 goto errout;
 175
 176                         /* free the wired memory used by the previous image */
 177                         if ( prev_image_ptr != NULL ) {
 178                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page(prev_image_size));
 179                                 printf("Panic UI memory freed (%p)\n", (void *)round_page(prev_image_size));
 180                         }
 181                 }
 182
 183                 break;
 184
 185 errout:
 186                 if ( newimage != (vm_offset_t )NULL )
 187                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page(newlen));
 188
 189                 break;
 190         }
 191
 192         /* adjust index so we return the right required/consumed amount */
 193         if (!error)
 194                 req->oldidx += req->oldlen;
 195
 196         return (error);
 197 }
 198 SYSCTL_PROC(_kern, KERN_PANICINFO, panicinfo, CTLTYPE_NODE|CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_ANYBODY,
 199         0,                      /* Pointer argument (arg1) */
 200         0,                      /* Integer argument (arg2) */
 201         sysctl_dopanicinfo,     /* Handler function */
 202         NULL,                   /* Data pointer */
 203         "");