loader/i386/multiboot.c

   1 /* multiboot.c - boot a multiboot OS image. */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009,2010  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /*
  21  *  FIXME: The following features from the Multiboot specification still
  22  *         need to be implemented:
  23  *  - VBE support
  24  *  - symbol table
  25  *  - drives table
  26  *  - ROM configuration table
  27  *  - APM table
  28  */
  29
  30 /* The bits in the required part of flags field we don't support.  */
  31 #define UNSUPPORTED_FLAGS                       0x0000fff8
  32
  33 #include <grub/loader.h>
  34 #include <grub/machine/loader.h>
  35 #include <grub/multiboot.h>
  36 #include <grub/cpu/multiboot.h>
  37 #include <grub/elf.h>
  38 #include <grub/aout.h>
  39 #include <grub/file.h>
  40 #include <grub/err.h>
  41 #include <grub/dl.h>
  42 #include <grub/mm.h>
  43 #include <grub/misc.h>
  44 #include <grub/gzio.h>
  45 #include <grub/env.h>
  46 #include <grub/i386/relocator.h>
  47 #include <grub/video.h>
  48
  49 #ifdef GRUB_MACHINE_EFI
  50 #include <grub/efi/efi.h>
  51 #endif
  52
  53 extern grub_dl_t my_mod;
  54 static grub_size_t code_size, alloc_mbi;
  55
  56 char *grub_multiboot_payload_orig;
  57 grub_addr_t grub_multiboot_payload_dest;
  58 grub_size_t grub_multiboot_pure_size;
  59 grub_uint32_t grub_multiboot_payload_eip;
  60
  61 static grub_err_t
  62 grub_multiboot_boot (void)
  63 {
  64   grub_size_t mbi_size;
  65   grub_err_t err;
  66   struct grub_relocator32_state state =
  67     {
  68       .eax = MULTIBOOT_BOOTLOADER_MAGIC,
  69       .ecx = 0,
  70       .edx = 0,
  71       .eip = grub_multiboot_payload_eip,
  72       /* Set esp to some random location in low memory to avoid breaking
  73          non-compliant kernels.  */
  74       .esp = 0x7ff00
  75     };
  76
  77   mbi_size = grub_multiboot_get_mbi_size ();
  78   if (alloc_mbi < mbi_size)
  79     {
  80       grub_multiboot_payload_orig
  81         = grub_relocator32_realloc (grub_multiboot_payload_orig,
  82                                     grub_multiboot_pure_size + mbi_size);
  83       if (!grub_multiboot_payload_orig)
  84         return grub_errno;
  85       alloc_mbi = mbi_size;
  86     }
  87
  88   state.ebx = grub_multiboot_payload_dest + grub_multiboot_pure_size;
  89   err = grub_multiboot_make_mbi (grub_multiboot_payload_orig,
  90                                  grub_multiboot_payload_dest,
  91                                  grub_multiboot_pure_size, mbi_size);
  92   if (err)
  93     return err;
  94
  95 #ifdef GRUB_MACHINE_EFI
  96   if (! grub_efi_finish_boot_services ())
  97      grub_fatal ("cannot exit boot services");
  98 #endif
  99
 100   grub_relocator32_boot (grub_multiboot_payload_orig,
 101                          grub_multiboot_payload_dest,
 102                          state);
 103
 104   /* Not reached.  */
 105   return GRUB_ERR_NONE;
 106 }
 107
 108 static grub_err_t
 109 grub_multiboot_unload (void)
 110 {
 111   grub_multiboot_free_mbi ();
 112
 113   grub_relocator32_free (grub_multiboot_payload_orig);
 114
 115   alloc_mbi = 0;
 116
 117   grub_multiboot_payload_orig = NULL;
 118   grub_dl_unref (my_mod);
 119
 120   return GRUB_ERR_NONE;
 121 }
 122
 123 #define MULTIBOOT_LOAD_ELF64
 124 #include "multiboot_elfxx.c"
 125 #undef MULTIBOOT_LOAD_ELF64
 126
 127 #define MULTIBOOT_LOAD_ELF32
 128 #include "multiboot_elfxx.c"
 129 #undef MULTIBOOT_LOAD_ELF32
 130
 131 /* Load ELF32 or ELF64.  */
 132 static grub_err_t
 133 grub_multiboot_load_elf (grub_file_t file, void *buffer)
 134 {
 135   if (grub_multiboot_is_elf32 (buffer))
 136     return grub_multiboot_load_elf32 (file, buffer);
 137   else if (grub_multiboot_is_elf64 (buffer))
 138     return grub_multiboot_load_elf64 (file, buffer);
 139
 140   return grub_error (GRUB_ERR_UNKNOWN_OS, "unknown ELF class");
 141 }
 142
 143 void
 144 grub_multiboot (int argc, char *argv[])
 145 {
 146   grub_file_t file = 0;
 147   char buffer[MULTIBOOT_SEARCH];
 148   struct multiboot_header *header;
 149   grub_ssize_t len;
 150
 151   grub_loader_unset ();
 152
 153   if (argc == 0)
 154     {
 155       grub_error (GRUB_ERR_BAD_ARGUMENT, "no kernel specified");
 156       goto fail;
 157     }
 158
 159   file = grub_gzfile_open (argv[0], 1);
 160   if (! file)
 161     {
 162       grub_error (GRUB_ERR_BAD_ARGUMENT, "couldn't open file");
 163       goto fail;
 164     }
 165
 166   len = grub_file_read (file, buffer, MULTIBOOT_SEARCH);
 167   if (len < 32)
 168     {
 169       grub_error (GRUB_ERR_BAD_OS, "file too small");
 170       goto fail;
 171     }
 172
 173   /* Look for the multiboot header in the buffer.  The header should
 174      be at least 12 bytes and aligned on a 4-byte boundary.  */
 175   for (header = (struct multiboot_header *) buffer;
 176        ((char *) header <= buffer + len - 12) || (header = 0);
 177        header = (struct multiboot_header *) ((char *) header + 4))
 178     {
 179       if (header->magic == MULTIBOOT_HEADER_MAGIC
 180           && !(header->magic + header->flags + header->checksum))
 181         break;
 182     }
 183
 184   if (header == 0)
 185     {
 186       grub_error (GRUB_ERR_BAD_ARGUMENT, "no multiboot header found");
 187       goto fail;
 188     }
 189
 190   if (header->flags & UNSUPPORTED_FLAGS)
 191     {
 192       grub_error (GRUB_ERR_UNKNOWN_OS,
 193                   "unsupported flag: 0x%x", header->flags);
 194       goto fail;
 195     }
 196
 197   grub_relocator32_free (grub_multiboot_payload_orig);
 198   grub_multiboot_payload_orig = NULL;
 199
 200   /* Skip filename.  */
 201   grub_multiboot_init_mbi (argc - 1, argv + 1);
 202
 203   if (header->flags & MULTIBOOT_AOUT_KLUDGE)
 204     {
 205       int offset = ((char *) header - buffer -
 206                     (header->header_addr - header->load_addr));
 207       int load_size = ((header->load_end_addr == 0) ? file->size - offset :
 208                        header->load_end_addr - header->load_addr);
 209
 210       if (header->bss_end_addr)
 211         code_size = (header->bss_end_addr - header->load_addr);
 212       else
 213         code_size = load_size;
 214       grub_multiboot_payload_dest = header->load_addr;
 215
 216       grub_multiboot_pure_size += code_size;
 217
 218       /* Allocate a bit more to avoid relocations in most cases.  */
 219       alloc_mbi = grub_multiboot_get_mbi_size () + 65536;
 220       grub_multiboot_payload_orig
 221         = grub_relocator32_alloc (grub_multiboot_pure_size + alloc_mbi);
 222
 223       if (! grub_multiboot_payload_orig)
 224         goto fail;
 225
 226       if ((grub_file_seek (file, offset)) == (grub_off_t) -1)
 227         goto fail;
 228
 229       grub_file_read (file, (void *) grub_multiboot_payload_orig, load_size);
 230       if (grub_errno)
 231         goto fail;
 232
 233       if (header->bss_end_addr)
 234         grub_memset ((void *) (grub_multiboot_payload_orig + load_size), 0,
 235                      header->bss_end_addr - header->load_addr - load_size);
 236
 237       grub_multiboot_payload_eip = header->entry_addr;
 238
 239     }
 240   else if (grub_multiboot_load_elf (file, buffer) != GRUB_ERR_NONE)
 241     goto fail;
 242
 243   if (header->flags & MULTIBOOT_VIDEO_MODE)
 244     {
 245       switch (header->mode_type)
 246         {
 247         case 1:
 248           grub_env_set ("gfxpayload", "text");
 249           break;
 250
 251         case 0:
 252           {
 253             char *buf;
 254             if (header->depth && header->width && header->height)
 255               buf = grub_xasprintf ("%dx%dx%d,%dx%d,auto", header->width,
 256                                    header->height, header->depth, header->width,
 257                                    header->height);
 258             else if (header->width && header->height)
 259               buf = grub_xasprintf ("%dx%d,auto", header->width, header->height);
 260             else
 261               buf = grub_strdup ("auto");
 262
 263             if (!buf)
 264               goto fail;
 265             grub_env_set ("gfxpayload", buf);
 266             grub_free (buf);
 267             break;
 268           }
 269         }
 270     }
 271
 272   grub_multiboot_set_accepts_video (!!(header->flags & MULTIBOOT_VIDEO_MODE));
 273
 274   grub_multiboot_set_bootdev ();
 275
 276   grub_loader_set (grub_multiboot_boot, grub_multiboot_unload, 0);
 277
 278  fail:
 279   if (file)
 280     grub_file_close (file);
 281
 282   if (grub_errno != GRUB_ERR_NONE)
 283     {
 284       grub_relocator32_free (grub_multiboot_payload_orig);
 285       grub_dl_unref (my_mod);
 286     }
 287 }
 288
 289 void
 290 grub_module  (int argc, char *argv[])
 291 {
 292   grub_file_t file = 0;
 293   grub_ssize_t size;
 294   char *module = 0;
 295   grub_err_t err;
 296
 297   if (argc == 0)
 298     {
 299       grub_error (GRUB_ERR_BAD_ARGUMENT, "no module specified");
 300       goto fail;
 301     }
 302
 303   if (!grub_multiboot_payload_orig)
 304     {
 305       grub_error (GRUB_ERR_BAD_ARGUMENT,
 306                   "you need to load the multiboot kernel first");
 307       goto fail;
 308     }
 309
 310   file = grub_gzfile_open (argv[0], 1);
 311   if (! file)
 312     goto fail;
 313
 314   size = grub_file_size (file);
 315   module = grub_memalign (MULTIBOOT_MOD_ALIGN, size);
 316   if (! module)
 317     goto fail;
 318
 319   err = grub_multiboot_add_module ((grub_addr_t) module, size,
 320                                    argc - 1, argv + 1);
 321   if (err)
 322     goto fail;
 323
 324   if (grub_file_read (file, module, size) != size)
 325     {
 326       grub_error (GRUB_ERR_FILE_READ_ERROR, "couldn't read file");
 327       goto fail;
 328     }
 329
 330  fail:
 331   if (file)
 332     grub_file_close (file);
 333 }
 334