bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <sys/param.h>
  25 #include <sys/fcntl.h>
  26 #include <sys/malloc.h>
  27 #include <sys/proc.h>
  28 #include <sys/sysctl.h>
  29 #include <sys/vnode.h>
  30 #include <sys/vm.h>
  31 #include <sys/systm.h>
  32
  33 #include <mach/mach_types.h>
  34 #include <mach/kern_return.h>
  35 #include <kern/kern_types.h>
  36 #include <vm/vm_kern.h>
  37
  38
  39 /* prototypes not exported by osfmk/console. */
  40 extern void panic_dialog_test( void );
  41 extern int  panic_dialog_set_image( const unsigned char * ptr, unsigned int size );
  42 extern void panic_dialog_get_image( unsigned char ** ptr, unsigned int * size );
  43
  44 /* make the compiler happy */
  45 extern int sysctl_dopanicinfo(int *, u_int, user_addr_t, size_t *, user_addr_t, size_t, struct proc *);
  46
  47
  48 #define PANIC_IMAGE_SIZE_LIMIT  (32 * 4096)                             /* 128K - Maximum amount of memory consumed for the panic UI */
  49 #define KERN_PANICINFO_TEST     (KERN_PANICINFO_IMAGE+2)                /* Allow the panic UI to be tested by root without causing a panic */
  50
  51 /* Local data */
  52 static int image_size_limit = PANIC_IMAGE_SIZE_LIMIT;
  53
  54 __private_extern__ int
  55 sysctl_dopanicinfo(name, namelen, oldp, oldlenp, newp, newlen, p)
  56         int *name;
  57         u_int namelen;
  58         user_addr_t oldp;
  59         size_t *oldlenp;
  60         user_addr_t newp;
  61         size_t newlen;
  62         struct proc *p;
  63 {
  64         int error = 0;
  65         vm_offset_t newimage = (vm_offset_t )NULL;
  66         kern_return_t   kret;
  67         unsigned char * prev_image_ptr;
  68         unsigned int prev_image_size;
  69
  70
  71         /* all sysctl names at this level are terminal */
  72         if (namelen != 1)
  73                 return (ENOTDIR);               /* overloaded */
  74
  75         if ( (error = proc_suser(p)) )  /* must be super user to muck with image */
  76                 return (error);
  77
  78         switch (name[0]) {
  79         default:
  80                 return (ENOTSUP);
  81
  82         case KERN_PANICINFO_TEST:
  83
  84                 panic_dialog_test();
  85                 return (0);
  86
  87         case KERN_PANICINFO_MAXSIZE:
  88
  89                 /* return the image size limits */
  90
  91                 newlen = 0;
  92                 newp = USER_ADDR_NULL;
  93
  94                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
  95
  96                 return (error);
  97
  98         case KERN_PANICINFO_IMAGE:
  99
 100                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
 101                 if ( newp != USER_ADDR_NULL ) {
 102
 103                         /* check the length of the incoming image before allocating space for it. */
 104                         if ( newlen > (size_t)image_size_limit )
 105                                 return (ENOMEM);
 106
 107                         /* allocate some kernel wired memory for the new image */
 108                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page_32(newlen));
 109
 110                         if (kret != KERN_SUCCESS) {
 111                                 switch (kret) {
 112                                 default:
 113                                         error = EINVAL;
 114                                         break;
 115                                 case KERN_NO_SPACE:
 116                                 case KERN_RESOURCE_SHORTAGE:
 117                                         error = ENOMEM;
 118                                         break;
 119                                 case KERN_PROTECTION_FAILURE:
 120                                         error = EPERM;
 121                                         break;
 122                                 }
 123
 124                                 return (error);
 125                         }
 126
 127                         /* copy the image in from user space */
 128                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 129                                 goto errout;
 130
 131                 } else {        /* setup to make the default image active */
 132
 133                         newimage = (vm_offset_t )NULL;
 134                         newlen = 0;
 135                 }
 136
 137                 /* get the current image location and size */
 138                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 139
 140                 /* did the caller request a copy of the previous image ? */
 141                 if ( oldp != USER_ADDR_NULL ) {
 142                         if ( *oldlenp < prev_image_size ) {
 143                                 error = ERANGE;
 144                                 goto errout;
 145                         }
 146
 147                         /* copy the image to user space or zero the size if the default image is active */
 148                         if ( prev_image_ptr != NULL ) {
 149                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 150                                         goto errout;
 151
 152                                 *oldlenp = prev_image_size;
 153                         }
 154                         else /* tell the user that the default image is active */
 155                                 *oldlenp = 0;
 156                 }
 157
 158                 /* Make the new image active, or reactivate the default image.
 159                    But, handle the special case of asking for the current image
 160                    without changing the current image.
 161                 */
 162
 163                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 164                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 165                                 goto errout;
 166
 167                         /* free the wired memory used by the previous image */
 168                         if ( prev_image_ptr != NULL ) {
 169                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page_32(prev_image_size));
 170                                 printf("Panic UI memory freed (%d)\n", round_page_32(prev_image_size));
 171                         }
 172                 }
 173
 174                 return (0);
 175
 176 errout:
 177                 if ( newimage != (vm_offset_t )NULL )
 178                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page_32(newlen));
 179
 180                 return (error);
 181         }
 182 }