bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #include <sys/param.h>
  32 #include <sys/fcntl.h>
  33 #include <sys/malloc.h>
  34 #include <sys/proc.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/vnode.h>
  37 #include <sys/vm.h>
  38 #include <sys/systm.h>
  39
  40 #include <mach/mach_types.h>
  41 #include <mach/kern_return.h>
  42 #include <kern/kern_types.h>
  43 #include <vm/vm_kern.h>
  44
  45
  46 /* prototypes not exported by osfmk/console. */
  47 extern void panic_dialog_test( void );
  48 extern int  panic_dialog_set_image( const unsigned char * ptr, unsigned int size );
  49 extern void panic_dialog_get_image( unsigned char ** ptr, unsigned int * size );
  50
  51 /* make the compiler happy */
  52 extern int sysctl_dopanicinfo(int *, u_int, user_addr_t, size_t *, user_addr_t, size_t, struct proc *);
  53
  54
  55 #define PANIC_IMAGE_SIZE_LIMIT  (32 * 4096)                             /* 128K - Maximum amount of memory consumed for the panic UI */
  56 #define KERN_PANICINFO_TEST     (KERN_PANICINFO_IMAGE+2)                /* Allow the panic UI to be tested by root without causing a panic */
  57
  58 /* Local data */
  59 static int image_size_limit = PANIC_IMAGE_SIZE_LIMIT;
  60
  61 __private_extern__ int
  62 sysctl_dopanicinfo(name, namelen, oldp, oldlenp, newp, newlen, p)
  63         int *name;
  64         u_int namelen;
  65         user_addr_t oldp;
  66         size_t *oldlenp;
  67         user_addr_t newp;
  68         size_t newlen;
  69         struct proc *p;
  70 {
  71         int error = 0;
  72         vm_offset_t newimage = (vm_offset_t )NULL;
  73         kern_return_t   kret;
  74         unsigned char * prev_image_ptr;
  75         unsigned int prev_image_size;
  76
  77
  78         /* all sysctl names at this level are terminal */
  79         if (namelen != 1)
  80                 return (ENOTDIR);               /* overloaded */
  81
  82         if ( (error = proc_suser(p)) )  /* must be super user to muck with image */
  83                 return (error);
  84
  85         switch (name[0]) {
  86         default:
  87                 return (ENOTSUP);
  88
  89         case KERN_PANICINFO_TEST:
  90
  91                 panic_dialog_test();
  92                 return (0);
  93
  94         case KERN_PANICINFO_MAXSIZE:
  95
  96                 /* return the image size limits */
  97
  98                 newlen = 0;
  99                 newp = USER_ADDR_NULL;
 100
 101                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
 102
 103                 return (error);
 104
 105         case KERN_PANICINFO_IMAGE:
 106
 107                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
 108                 if ( newp != USER_ADDR_NULL ) {
 109
 110                         /* check the length of the incoming image before allocating space for it. */
 111                         if ( newlen > (size_t)image_size_limit )
 112                                 return (ENOMEM);
 113
 114                         /* allocate some kernel wired memory for the new image */
 115                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page_32(newlen));
 116
 117                         if (kret != KERN_SUCCESS) {
 118                                 switch (kret) {
 119                                 default:
 120                                         error = EINVAL;
 121                                         break;
 122                                 case KERN_NO_SPACE:
 123                                 case KERN_RESOURCE_SHORTAGE:
 124                                         error = ENOMEM;
 125                                         break;
 126                                 case KERN_PROTECTION_FAILURE:
 127                                         error = EPERM;
 128                                         break;
 129                                 }
 130
 131                                 return (error);
 132                         }
 133
 134                         /* copy the image in from user space */
 135                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 136                                 goto errout;
 137
 138                 } else {        /* setup to make the default image active */
 139
 140                         newimage = (vm_offset_t )NULL;
 141                         newlen = 0;
 142                 }
 143
 144                 /* get the current image location and size */
 145                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 146
 147                 /* did the caller request a copy of the previous image ? */
 148                 if ( oldp != USER_ADDR_NULL ) {
 149                         if ( *oldlenp < prev_image_size ) {
 150                                 error = ERANGE;
 151                                 goto errout;
 152                         }
 153
 154                         /* copy the image to user space or zero the size if the default image is active */
 155                         if ( prev_image_ptr != NULL ) {
 156                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 157                                         goto errout;
 158
 159                                 *oldlenp = prev_image_size;
 160                         }
 161                         else /* tell the user that the default image is active */
 162                                 *oldlenp = 0;
 163                 }
 164
 165                 /* Make the new image active, or reactivate the default image.
 166                    But, handle the special case of asking for the current image
 167                    without changing the current image.
 168                 */
 169
 170                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 171                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 172                                 goto errout;
 173
 174                         /* free the wired memory used by the previous image */
 175                         if ( prev_image_ptr != NULL ) {
 176                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page_32(prev_image_size));
 177                                 printf("Panic UI memory freed (%d)\n", round_page_32(prev_image_size));
 178                         }
 179                 }
 180
 181                 return (0);
 182
 183 errout:
 184                 if ( newimage != (vm_offset_t )NULL )
 185                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page_32(newlen));
 186
 187                 return (error);
 188         }
 189 }