grub-core/loader/multiboot_elfxx.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #if defined(MULTIBOOT_LOAD_ELF32)
  20 # define XX             32
  21 # define E_MACHINE      MULTIBOOT_ELF32_MACHINE
  22 # define ELFCLASSXX     ELFCLASS32
  23 # define Elf_Ehdr       Elf32_Ehdr
  24 # define Elf_Phdr       Elf32_Phdr
  25 # define Elf_Shdr       Elf32_Shdr
  26 #elif defined(MULTIBOOT_LOAD_ELF64)
  27 # define XX             64
  28 # define E_MACHINE      MULTIBOOT_ELF64_MACHINE
  29 # define ELFCLASSXX     ELFCLASS64
  30 # define Elf_Ehdr       Elf64_Ehdr
  31 # define Elf_Phdr       Elf64_Phdr
  32 # define Elf_Shdr       Elf64_Shdr
  33 #else
  34 #error "I'm confused"
  35 #endif
  36
  37 #include <grub/i386/relocator.h>
  38
  39 #define CONCAT(a,b)     CONCAT_(a, b)
  40 #define CONCAT_(a,b)    a ## b
  41
  42 #pragma GCC diagnostic ignored "-Wcast-align"
  43
  44 /* Check if BUFFER contains ELF32 (or ELF64).  */
  45 static int
  46 CONCAT(grub_multiboot_is_elf, XX) (void *buffer)
  47 {
  48   Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
  49
  50   return ehdr->e_ident[EI_CLASS] == ELFCLASSXX;
  51 }
  52
  53 static grub_err_t
  54 CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, void *buffer)
  55 {
  56   Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
  57   char *phdr_base;
  58   int i;
  59
  60   if (ehdr->e_ident[EI_MAG0] != ELFMAG0
  61       || ehdr->e_ident[EI_MAG1] != ELFMAG1
  62       || ehdr->e_ident[EI_MAG2] != ELFMAG2
  63       || ehdr->e_ident[EI_MAG3] != ELFMAG3
  64       || ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
  65     return grub_error(GRUB_ERR_UNKNOWN_OS, N_("invalid arch-independent ELF magic"));
  66
  67   if (ehdr->e_ident[EI_CLASS] != ELFCLASSXX || ehdr->e_machine != E_MACHINE
  68       || ehdr->e_version != EV_CURRENT)
  69     return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF magic"));
  70
  71   if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
  72     return grub_error (GRUB_ERR_UNKNOWN_OS, N_("this ELF file is not of the right type"));
  73
  74   /* FIXME: Should we support program headers at strange locations?  */
  75   if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
  76     return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
  77
  78 #ifdef MULTIBOOT_LOAD_ELF64
  79 # ifdef __mips
  80   /* We still in 32-bit mode.  */
  81   if (ehdr->e_entry < 0xffffffff80000000ULL)
  82     return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
  83 # else
  84   /* We still in 32-bit mode.  */
  85   if (ehdr->e_entry > 0xffffffff)
  86     return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
  87 # endif
  88 #endif
  89
  90   phdr_base = (char *) buffer + ehdr->e_phoff;
  91 #define phdr(i)                 ((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
  92
  93   /* Load every loadable segment in memory.  */
  94   for (i = 0; i < ehdr->e_phnum; i++)
  95     {
  96       if (phdr(i)->p_type == PT_LOAD)
  97         {
  98           grub_err_t err;
  99           void *source;
 100
 101           grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n",
 102                         i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr);
 103
 104           {
 105             grub_relocator_chunk_t ch;
 106             err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
 107                                                    &ch, phdr(i)->p_paddr,
 108                                                    phdr(i)->p_memsz);
 109             if (err)
 110               {
 111                 grub_dprintf ("multiboot_loader", "Error loading phdr %d\n", i);
 112                 return err;
 113               }
 114             source = get_virtual_current_address (ch);
 115           }
 116
 117           if (phdr(i)->p_filesz != 0)
 118             {
 119               if (grub_file_seek (file, (grub_off_t) phdr(i)->p_offset)
 120                   == (grub_off_t) -1)
 121                 return grub_errno;
 122
 123               if (grub_file_read (file, source, phdr(i)->p_filesz)
 124                   != (grub_ssize_t) phdr(i)->p_filesz)
 125                 {
 126                   if (!grub_errno)
 127                     grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 128                                 filename);
 129                   return grub_errno;
 130                 }
 131             }
 132
 133           if (phdr(i)->p_filesz < phdr(i)->p_memsz)
 134             grub_memset ((grub_uint8_t *) source + phdr(i)->p_filesz, 0,
 135                          phdr(i)->p_memsz - phdr(i)->p_filesz);
 136         }
 137     }
 138
 139   for (i = 0; i < ehdr->e_phnum; i++)
 140     if (phdr(i)->p_vaddr <= ehdr->e_entry
 141         && phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry)
 142       {
 143         grub_multiboot_payload_eip = (ehdr->e_entry - phdr(i)->p_vaddr)
 144           + phdr(i)->p_paddr;
 145         break;
 146       }
 147
 148   if (i == ehdr->e_phnum)
 149     return grub_error (GRUB_ERR_BAD_OS, "entry point isn't in a segment");
 150
 151 #if defined (__i386__) || defined (__x86_64__)
 152
 153 #elif defined (__mips)
 154   grub_multiboot_payload_eip |= 0x80000000;
 155 #else
 156 #error Please complete this
 157 #endif
 158
 159   if (ehdr->e_shnum)
 160     {
 161       grub_uint8_t *shdr, *shdrptr;
 162
 163       shdr = grub_malloc (ehdr->e_shnum * ehdr->e_shentsize);
 164       if (!shdr)
 165         return grub_errno;
 166
 167       if (grub_file_seek (file, ehdr->e_shoff) == (grub_off_t) -1)
 168         return grub_errno;
 169
 170       if (grub_file_read (file, shdr, ehdr->e_shnum * ehdr->e_shentsize)
 171               != (grub_ssize_t) ehdr->e_shnum * ehdr->e_shentsize)
 172         {
 173           if (!grub_errno)
 174             grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 175                         filename);
 176           return grub_errno;
 177         }
 178
 179       for (shdrptr = shdr, i = 0; i < ehdr->e_shnum;
 180            shdrptr += ehdr->e_shentsize, i++)
 181         {
 182           Elf_Shdr *sh = (Elf_Shdr *) shdrptr;
 183           void *src;
 184           grub_addr_t target;
 185           grub_err_t err;
 186
 187           /* This section is a loaded section,
 188              so we don't care.  */
 189           if (sh->sh_addr != 0)
 190             continue;
 191
 192           /* This section is empty, so we don't care.  */
 193           if (sh->sh_size == 0)
 194             continue;
 195
 196           {
 197             grub_relocator_chunk_t ch;
 198             err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator,
 199                                                     &ch, 0,
 200                                                     (0xffffffff - sh->sh_size)
 201                                                     + 1, sh->sh_size,
 202                                                     sh->sh_addralign,
 203                                                     GRUB_RELOCATOR_PREFERENCE_NONE);
 204             if (err)
 205               {
 206                 grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
 207                 return err;
 208               }
 209             src = get_virtual_current_address (ch);
 210             target = get_physical_target_address (ch);
 211           }
 212
 213           if (grub_file_seek (file, sh->sh_offset) == (grub_off_t) -1)
 214             return grub_errno;
 215
 216           if (grub_file_read (file, src, sh->sh_size)
 217               != (grub_ssize_t) sh->sh_size)
 218             {
 219               if (!grub_errno)
 220                 grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 221                             filename);
 222               return grub_errno;
 223             }
 224           sh->sh_addr = target;
 225         }
 226       grub_multiboot_add_elfsyms (ehdr->e_shnum, ehdr->e_shentsize,
 227                                   ehdr->e_shstrndx, shdr);
 228     }
 229
 230 #undef phdr
 231
 232   return grub_errno;
 233 }
 234
 235 #undef XX
 236 #undef E_MACHINE
 237 #undef ELFCLASSXX
 238 #undef Elf_Ehdr
 239 #undef Elf_Phdr
 240 #undef Elf_Shdr