grub/grub-core/efiemu/loadcore.c

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/* Load runtime image of EFIemu. Functions specific to 32/64-bit mode */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/err.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/efiemu/efiemu.h>
#include <grub/cpu/efiemu.h>
#include <grub/elf.h>
#include <grub/i18n.h>
/* ELF symbols and their values */
static struct grub_efiemu_elf_sym *grub_efiemu_elfsyms = 0;
static int grub_efiemu_nelfsyms = 0;
/* Return the address of a section whose index is N. */
static grub_err_t
grub_efiemu_get_section_addr (grub_efiemu_segment_t segs, unsigned n,
int *handle, grub_off_t *off)
{
grub_efiemu_segment_t seg;
for (seg = segs; seg; seg = seg->next)
if (seg->section == n)
{
*handle = seg->handle;
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*off = seg->off;
return GRUB_ERR_NONE;
}
return grub_error (GRUB_ERR_BAD_OS, "section %d not found", n);
}
grub_err_t
SUFFIX (grub_efiemu_loadcore_unload) (void)
{
grub_free (grub_efiemu_elfsyms);
grub_efiemu_elfsyms = 0;
return GRUB_ERR_NONE;
}
/* Check if EHDR is a valid ELF header. */
int
SUFFIX (grub_efiemu_check_header) (void *ehdr, grub_size_t size)
{
Elf_Ehdr *e = ehdr;
/* Check the header size. */
if (size < sizeof (Elf_Ehdr))
return 0;
/* Check the magic numbers. */
if (!SUFFIX (grub_arch_efiemu_check_header) (ehdr)
|| e->e_ident[EI_MAG0] != ELFMAG0
|| e->e_ident[EI_MAG1] != ELFMAG1
|| e->e_ident[EI_MAG2] != ELFMAG2
|| e->e_ident[EI_MAG3] != ELFMAG3
|| e->e_ident[EI_VERSION] != EV_CURRENT
|| e->e_version != EV_CURRENT)
return 0;
return 1;
}
/* Load all segments from memory specified by E. */
static grub_err_t
grub_efiemu_load_segments (grub_efiemu_segment_t segs, const Elf_Ehdr *e)
{
Elf_Shdr *s;
grub_efiemu_segment_t cur;
grub_dprintf ("efiemu", "loading segments\n");
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for (cur=segs; cur; cur = cur->next)
{
s = (Elf_Shdr *)cur->srcptr;
if ((s->sh_flags & SHF_ALLOC) && s->sh_size)
{
void *addr;
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addr = (grub_uint8_t *) grub_efiemu_mm_obtain_request (cur->handle)
+ cur->off;
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switch (s->sh_type)
{
case SHT_PROGBITS:
grub_memcpy (addr, (char *) e + s->sh_offset, s->sh_size);
break;
case SHT_NOBITS:
grub_memset (addr, 0, s->sh_size);
break;
}
}
}
return GRUB_ERR_NONE;
}
/* Get a string at offset OFFSET from strtab */
static char *
grub_efiemu_get_string (unsigned offset, const Elf_Ehdr *e)
{
unsigned i;
Elf_Shdr *s;
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_STRTAB && offset < s->sh_size)
return (char *) e + s->sh_offset + offset;
return 0;
}
/* Request memory for segments and fill segments info */
static grub_err_t
grub_efiemu_init_segments (grub_efiemu_segment_t *segs, const Elf_Ehdr *e)
{
unsigned i;
Elf_Shdr *s;
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
{
if (s->sh_flags & SHF_ALLOC)
{
grub_efiemu_segment_t seg;
seg = (grub_efiemu_segment_t) grub_malloc (sizeof (*seg));
if (! seg)
return grub_errno;
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if (s->sh_size)
{
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seg->handle
= grub_efiemu_request_memalign
(s->sh_addralign, s->sh_size,
s->sh_flags & SHF_EXECINSTR ? GRUB_EFI_RUNTIME_SERVICES_CODE
: GRUB_EFI_RUNTIME_SERVICES_DATA);
if (seg->handle < 0)
return grub_errno;
seg->off = 0;
}
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/*
.text-physical doesn't need to be relocated when switching to
virtual mode
*/
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if (!grub_strcmp (grub_efiemu_get_string (s->sh_name, e),
".text-physical"))
seg->ptv_rel_needed = 0;
else
seg->ptv_rel_needed = 1;
seg->size = s->sh_size;
seg->section = i;
seg->next = *segs;
seg->srcptr = s;
*segs = seg;
}
}
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return GRUB_ERR_NONE;
}
/* Count symbols and relocators and allocate/request memory for them */
static grub_err_t
grub_efiemu_count_symbols (const Elf_Ehdr *e)
{
unsigned i;
Elf_Shdr *s;
int num = 0;
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/* Symbols */
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_SYMTAB)
break;
if (i == e->e_shnum)
return grub_error (GRUB_ERR_BAD_OS, N_("no symbol table"));
grub_efiemu_nelfsyms = (unsigned) s->sh_size / (unsigned) s->sh_entsize;
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grub_efiemu_elfsyms = (struct grub_efiemu_elf_sym *)
grub_malloc (sizeof (struct grub_efiemu_elf_sym) * grub_efiemu_nelfsyms);
/* Relocators */
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_REL || s->sh_type == SHT_RELA)
num += ((unsigned) s->sh_size) / ((unsigned) s->sh_entsize);
grub_efiemu_request_symbols (num);
return GRUB_ERR_NONE;
}
/* Fill grub_efiemu_elfsyms with symbol values */
static grub_err_t
grub_efiemu_resolve_symbols (grub_efiemu_segment_t segs, Elf_Ehdr *e)
{
unsigned i;
Elf_Shdr *s;
Elf_Sym *sym;
const char *str;
Elf_Word size, entsize;
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grub_dprintf ("efiemu", "resolving symbols\n");
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_SYMTAB)
break;
if (i == e->e_shnum)
return grub_error (GRUB_ERR_BAD_OS, N_("no symbol table"));
sym = (Elf_Sym *) ((char *) e + s->sh_offset);
size = s->sh_size;
entsize = s->sh_entsize;
s = (Elf_Shdr *) ((char *) e + e->e_shoff + e->e_shentsize * s->sh_link);
str = (char *) e + s->sh_offset;
for (i = 0;
i < size / entsize;
i++, sym = (Elf_Sym *) ((char *) sym + entsize))
{
unsigned char type = ELF_ST_TYPE (sym->st_info);
unsigned char bind = ELF_ST_BIND (sym->st_info);
int handle;
grub_off_t off;
grub_err_t err;
const char *name = str + sym->st_name;
grub_efiemu_elfsyms[i].section = sym->st_shndx;
switch (type)
{
case STT_NOTYPE:
/* Resolve a global symbol. */
if (sym->st_name != 0 && sym->st_shndx == 0)
{
err = grub_efiemu_resolve_symbol (name, &handle, &off);
if (err)
return err;
grub_efiemu_elfsyms[i].handle = handle;
grub_efiemu_elfsyms[i].off = off;
}
else
sym->st_value = 0;
break;
case STT_OBJECT:
err = grub_efiemu_get_section_addr (segs, sym->st_shndx,
&handle, &off);
if (err)
return err;
off += sym->st_value;
if (bind != STB_LOCAL)
{
err = grub_efiemu_register_symbol (name, handle, off);
if (err)
return err;
}
grub_efiemu_elfsyms[i].handle = handle;
grub_efiemu_elfsyms[i].off = off;
break;
case STT_FUNC:
err = grub_efiemu_get_section_addr (segs, sym->st_shndx,
&handle, &off);
if (err)
return err;
off += sym->st_value;
if (bind != STB_LOCAL)
{
err = grub_efiemu_register_symbol (name, handle, off);
if (err)
return err;
}
grub_efiemu_elfsyms[i].handle = handle;
grub_efiemu_elfsyms[i].off = off;
break;
case STT_SECTION:
err = grub_efiemu_get_section_addr (segs, sym->st_shndx,
&handle, &off);
if (err)
{
grub_efiemu_elfsyms[i].handle = 0;
grub_efiemu_elfsyms[i].off = 0;
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grub_errno = GRUB_ERR_NONE;
break;
}
grub_efiemu_elfsyms[i].handle = handle;
grub_efiemu_elfsyms[i].off = off;
break;
case STT_FILE:
grub_efiemu_elfsyms[i].handle = 0;
grub_efiemu_elfsyms[i].off = 0;
break;
default:
return grub_error (GRUB_ERR_BAD_MODULE,
"unknown symbol type `%d'", (int) type);
}
}
return GRUB_ERR_NONE;
}
/* Load runtime to the memory and request memory for definitive location*/
grub_err_t
SUFFIX (grub_efiemu_loadcore_init) (void *core, const char *filename,
grub_size_t core_size,
grub_efiemu_segment_t *segments)
{
Elf_Ehdr *e = (Elf_Ehdr *) core;
grub_err_t err;
if (e->e_type != ET_REL)
return grub_error (GRUB_ERR_BAD_MODULE, N_("this ELF file is not of the right type"));
/* Make sure that every section is within the core. */
if ((grub_size_t) core_size < e->e_shoff + (grub_uint32_t) e->e_shentsize * e->e_shnum)
return grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
filename);
err = grub_efiemu_init_segments (segments, core);
if (err)
return err;
err = grub_efiemu_count_symbols (core);
if (err)
return err;
grub_efiemu_request_symbols (1);
return GRUB_ERR_NONE;
}
/* Load runtime definitively */
grub_err_t
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SUFFIX (grub_efiemu_loadcore_load) (void *core,
grub_size_t core_size
__attribute__ ((unused)),
grub_efiemu_segment_t segments)
{
grub_err_t err;
err = grub_efiemu_load_segments (segments, core);
if (err)
return err;
err = grub_efiemu_resolve_symbols (segments, core);
if (err)
return err;
err = SUFFIX (grub_arch_efiemu_relocate_symbols) (segments,
grub_efiemu_elfsyms,
core);
if (err)
return err;
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return GRUB_ERR_NONE;
}