bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002 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 extern int sysctl_dopanicinfo(int *, u_int, user_addr_t, size_t *, user_addr_t, size_t, struct proc *);
  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 __private_extern__ int
  60 sysctl_dopanicinfo(name, namelen, oldp, oldlenp, newp, newlen, p)
  61         int *name;
  62         u_int namelen;
  63         user_addr_t oldp;
  64         size_t *oldlenp;
  65         user_addr_t newp;
  66         size_t newlen;
  67         struct proc *p;
  68 {
  69         int error = 0;
  70         vm_offset_t newimage = (vm_offset_t )NULL;
  71         kern_return_t   kret;
  72         unsigned char * prev_image_ptr;
  73         unsigned int prev_image_size;
  74
  75
  76         /* all sysctl names at this level are terminal */
  77         if (namelen != 1)
  78                 return (ENOTDIR);               /* overloaded */
  79
  80         if ( (error = proc_suser(p)) )  /* must be super user to muck with image */
  81                 return (error);
  82
  83         switch (name[0]) {
  84         default:
  85                 return (ENOTSUP);
  86
  87         case KERN_PANICINFO_TEST:
  88
  89                 panic_dialog_test();
  90                 return (0);
  91
  92         case KERN_PANICINFO_MAXSIZE:
  93
  94                 /* return the image size limits */
  95
  96                 newlen = 0;
  97                 newp = USER_ADDR_NULL;
  98
  99                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
 100
 101                 return (error);
 102
 103         case KERN_PANICINFO_IMAGE:
 104
 105                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
 106                 if ( newp != USER_ADDR_NULL ) {
 107
 108                         /* check the length of the incoming image before allocating space for it. */
 109                         if ( newlen > (size_t)image_size_limit )
 110                                 return (ENOMEM);
 111
 112                         /* allocate some kernel wired memory for the new image */
 113                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page_32(newlen));
 114
 115                         if (kret != KERN_SUCCESS) {
 116                                 switch (kret) {
 117                                 default:
 118                                         error = EINVAL;
 119                                         break;
 120                                 case KERN_NO_SPACE:
 121                                 case KERN_RESOURCE_SHORTAGE:
 122                                         error = ENOMEM;
 123                                         break;
 124                                 case KERN_PROTECTION_FAILURE:
 125                                         error = EPERM;
 126                                         break;
 127                                 }
 128
 129                                 return (error);
 130                         }
 131
 132                         /* copy the image in from user space */
 133                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 134                                 goto errout;
 135
 136                 } else {        /* setup to make the default image active */
 137
 138                         newimage = (vm_offset_t )NULL;
 139                         newlen = 0;
 140                 }
 141
 142                 /* get the current image location and size */
 143                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 144
 145                 /* did the caller request a copy of the previous image ? */
 146                 if ( oldp != USER_ADDR_NULL ) {
 147                         if ( *oldlenp < prev_image_size ) {
 148                                 error = ERANGE;
 149                                 goto errout;
 150                         }
 151
 152                         /* copy the image to user space or zero the size if the default image is active */
 153                         if ( prev_image_ptr != NULL ) {
 154                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 155                                         goto errout;
 156
 157                                 *oldlenp = prev_image_size;
 158                         }
 159                         else /* tell the user that the default image is active */
 160                                 *oldlenp = 0;
 161                 }
 162
 163                 /* Make the new image active, or reactivate the default image.
 164                    But, handle the special case of asking for the current image
 165                    without changing the current image.
 166                 */
 167
 168                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 169                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 170                                 goto errout;
 171
 172                         /* free the wired memory used by the previous image */
 173                         if ( prev_image_ptr != NULL ) {
 174                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page_32(prev_image_size));
 175                                 printf("Panic UI memory freed (%d)\n", round_page_32(prev_image_size));
 176                         }
 177                 }
 178
 179                 return (0);
 180
 181 errout:
 182                 if ( newimage != (vm_offset_t )NULL )
 183                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page_32(newlen));
 184
 185                 return (error);
 186         }
 187 }