bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 #include <sys/param.h>
  24 #include <sys/fcntl.h>
  25 #include <sys/malloc.h>
  26 #include <sys/proc.h>
  27 #include <sys/sysctl.h>
  28 #include <sys/vnode.h>
  29 #include <sys/vm.h>
  30 #include <sys/systm.h>
  31
  32 #include <mach/mach_types.h>
  33 #include <mach/kern_return.h>
  34 #include <kern/kern_types.h>
  35 #include <vm/vm_kern.h>
  36
  37
  38 /* prototypes not exported by osfmk/console. */
  39 extern void panic_dialog_test( void );
  40 extern int  panic_dialog_set_image( const unsigned char * ptr, unsigned int size );
  41 extern void panic_dialog_get_image( unsigned char ** ptr, unsigned int * size );
  42
  43 /* make the compiler happy */
  44 extern int sysctl_dopanicinfo(int *, u_int, user_addr_t, size_t *, user_addr_t, size_t, struct proc *);
  45
  46
  47 #define PANIC_IMAGE_SIZE_LIMIT  (32 * 4096)                             /* 128K - Maximum amount of memory consumed for the panic UI */
  48 #define KERN_PANICINFO_TEST     (KERN_PANICINFO_IMAGE+2)                /* Allow the panic UI to be tested by root without causing a panic */
  49
  50 /* Local data */
  51 static int image_size_limit = PANIC_IMAGE_SIZE_LIMIT;
  52
  53 __private_extern__ int
  54 sysctl_dopanicinfo(name, namelen, oldp, oldlenp, newp, newlen, p)
  55         int *name;
  56         u_int namelen;
  57         user_addr_t oldp;
  58         size_t *oldlenp;
  59         user_addr_t newp;
  60         size_t newlen;
  61         struct proc *p;
  62 {
  63         int error = 0;
  64         vm_offset_t newimage = (vm_offset_t )NULL;
  65         kern_return_t   kret;
  66         unsigned char * prev_image_ptr;
  67         unsigned int prev_image_size;
  68
  69
  70         /* all sysctl names at this level are terminal */
  71         if (namelen != 1)
  72                 return (ENOTDIR);               /* overloaded */
  73
  74         if ( (error = proc_suser(p)) )  /* must be super user to muck with image */
  75                 return (error);
  76
  77         switch (name[0]) {
  78         default:
  79                 return (ENOTSUP);
  80
  81         case KERN_PANICINFO_TEST:
  82
  83                 panic_dialog_test();
  84                 return (0);
  85
  86         case KERN_PANICINFO_MAXSIZE:
  87
  88                 /* return the image size limits */
  89
  90                 newlen = 0;
  91                 newp = USER_ADDR_NULL;
  92
  93                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
  94
  95                 return (error);
  96
  97         case KERN_PANICINFO_IMAGE:
  98
  99                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
 100                 if ( newp != USER_ADDR_NULL ) {
 101
 102                         /* check the length of the incoming image before allocating space for it. */
 103                         if ( newlen > (size_t)image_size_limit )
 104                                 return (ENOMEM);
 105
 106                         /* allocate some kernel wired memory for the new image */
 107                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page_32(newlen));
 108
 109                         if (kret != KERN_SUCCESS) {
 110                                 switch (kret) {
 111                                 default:
 112                                         error = EINVAL;
 113                                         break;
 114                                 case KERN_NO_SPACE:
 115                                 case KERN_RESOURCE_SHORTAGE:
 116                                         error = ENOMEM;
 117                                         break;
 118                                 case KERN_PROTECTION_FAILURE:
 119                                         error = EPERM;
 120                                         break;
 121                                 }
 122
 123                                 return (error);
 124                         }
 125
 126                         /* copy the image in from user space */
 127                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 128                                 goto errout;
 129
 130                 } else {        /* setup to make the default image active */
 131
 132                         newimage = (vm_offset_t )NULL;
 133                         newlen = 0;
 134                 }
 135
 136                 /* get the current image location and size */
 137                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 138
 139                 /* did the caller request a copy of the previous image ? */
 140                 if ( oldp != USER_ADDR_NULL ) {
 141                         if ( *oldlenp < prev_image_size ) {
 142                                 error = ERANGE;
 143                                 goto errout;
 144                         }
 145
 146                         /* copy the image to user space or zero the size if the default image is active */
 147                         if ( prev_image_ptr != NULL ) {
 148                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 149                                         goto errout;
 150
 151                                 *oldlenp = prev_image_size;
 152                         }
 153                         else /* tell the user that the default image is active */
 154                                 *oldlenp = 0;
 155                 }
 156
 157                 /* Make the new image active, or reactivate the default image.
 158                    But, handle the special case of asking for the current image
 159                    without changing the current image.
 160                 */
 161
 162                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 163                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 164                                 goto errout;
 165
 166                         /* free the wired memory used by the previous image */
 167                         if ( prev_image_ptr != NULL ) {
 168                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page_32(prev_image_size));
 169                                 printf("Panic UI memory freed (%d)\n", round_page_32(prev_image_size));
 170                         }
 171                 }
 172
 173                 return (0);
 174
 175 errout:
 176                 if ( newimage != (vm_offset_t )NULL )
 177                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page_32(newlen));
 178
 179                 return (error);
 180         }
 181 }