src/arch/i386/image/pxe_image.c

   1 /*
   2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 /**
  22  * @file
  23  *
  24  * PXE image format
  25  *
  26  */
  27
  28 #include <pxe.h>
  29 #include <pxe_call.h>
  30 #include <gpxe/uaccess.h>
  31 #include <gpxe/image.h>
  32 #include <gpxe/segment.h>
  33 #include <gpxe/netdevice.h>
  34 #include <gpxe/features.h>
  35
  36 FEATURE ( FEATURE_IMAGE, "PXE", DHCP_EB_FEATURE_PXE, 1 );
  37
  38 struct image_type pxe_image_type __image_type ( PROBE_PXE );
  39
  40 /**
  41  * Execute PXE image
  42  *
  43  * @v image             PXE image
  44  * @ret rc              Return status code
  45  */
  46 static int pxe_exec ( struct image *image ) {
  47         struct net_device *netdev;
  48         int rc;
  49
  50         /* Arbitrarily pick the most recently opened network device */
  51         if ( ( netdev = last_opened_netdev() ) == NULL ) {
  52                 DBGC ( image, "IMAGE %p could not locate PXE net device\n",
  53                        image );
  54                 return -ENODEV;
  55         }
  56
  57         /* Activate PXE */
  58         pxe_activate ( netdev );
  59
  60         /* Start PXE NBP */
  61         rc = pxe_start_nbp();
  62
  63         /* Deactivate PXE */
  64         pxe_deactivate();
  65
  66         return rc;
  67 }
  68
  69 /**
  70  * Load PXE image into memory
  71  *
  72  * @v image             PXE file
  73  * @ret rc              Return status code
  74  */
  75 int pxe_load ( struct image *image ) {
  76         userptr_t buffer = real_to_user ( 0, 0x7c00 );
  77         size_t filesz = image->len;
  78         size_t memsz = image->len;
  79         int rc;
  80
  81         /* Images too large to fit in base memory cannot be PXE
  82          * images.  We include this check to help prevent unrecognised
  83          * images from being marked as PXE images, since PXE images
  84          * have no signature we can check against.
  85          */
  86         if ( filesz > ( 0xa0000 - 0x7c00 ) )
  87                 return -ENOEXEC;
  88
  89         /* Rejecting zero-length images is also useful, since these
  90          * end up looking to the user like bugs in gPXE.
  91          */
  92         if ( ! filesz )
  93                 return -ENOEXEC;
  94
  95         /* There are no signature checks for PXE; we will accept anything */
  96         if ( ! image->type )
  97                 image->type = &pxe_image_type;
  98
  99         /* Verify and prepare segment */
 100         if ( ( rc = prep_segment ( buffer, filesz, memsz ) ) != 0 ) {
 101                 DBGC ( image, "IMAGE %p could not prepare segment: %s\n",
 102                        image, strerror ( rc ) );
 103                 return rc;
 104         }
 105
 106         /* Copy image to segment */
 107         memcpy_user ( buffer, 0, image->data, 0, filesz );
 108
 109         return 0;
 110 }
 111
 112 /** PXE image type */
 113 struct image_type pxe_image_type __image_type ( PROBE_PXE ) = {
 114         .name = "PXE",
 115         .load = pxe_load,
 116         .exec = pxe_exec,
 117 };