/*
* Copyright (C) 2006 Sergey Bondari
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <elf.h>
#include <debug.h>
#include <arch/types.h>
#include <typedefs.h>
#include <mm/as.h>
#include <mm/frame.h>
#include <print.h>
#include <align.h>
static char *error_codes[] = {
"no error",
"invalid image",
"address space error",
"incompatible image",
"unsupported image type",
"irrecoverable error"
};
static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
static int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
/** ELF loader
*
* @param header Pointer to ELF header in memory
* @param as Created and properly mapped address space
* @return EE_OK on success
*/
int elf_load(elf_header_t *header, as_t * as)
{
int i, rc;
/* Identify ELF */
if (header->e_ident[EI_MAG0] != ELFMAG0 || header->e_ident[EI_MAG1] != ELFMAG1 ||
header->e_ident[EI_MAG2] != ELFMAG2 || header->e_ident[EI_MAG3] != ELFMAG3) {
return EE_INVALID;
}
/* Identify ELF compatibility */
if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || header->e_machine != ELF_MACHINE ||
header->e_ident[EI_VERSION] != EV_CURRENT || header->e_version != EV_CURRENT ||
header->e_ident[EI_CLASS] != ELF_CLASS) {
return EE_INCOMPATIBLE;
}
if (header->e_phentsize != sizeof(elf_ph_entry_t))
return EE_INCOMPATIBLE;
/* Check if the object type is supported. */
if (header->e_type != ET_EXEC)
return EE_UNSUPPORTED;
/* Walk through all program header entries and process them. */
for (i = 0; i < header->e_phnum; i++) {
rc = program_header_entry(header, &((elf_ph_entry_t *)(((__u8 *) header) + header->e_phoff))[i], as);
if (rc != EE_OK)
return rc;
}
return EE_OK;
}
/** Print error message according to error code.
*
* @param rc Return code returned by elf_load().
*
* @return NULL terminated description of error.
*/
char *elf_error(int rc)
{
ASSERT(rc < sizeof(error_codes)/sizeof(char *));
return error_codes[rc];
}
/** Process program header entry.
*
* @param entry Program header entry.
* @param as Address space into wich the ELF is being loaded.
*
* @return EE_OK on success, error code otherwise.
*/
static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
{
switch (entry->p_type) {
case PT_NULL:
case PT_PHDR:
break;
case PT_LOAD:
return load_segment(header, entry, as);
break;
case PT_DYNAMIC:
case PT_INTERP:
case PT_SHLIB:
case PT_NOTE:
case PT_LOPROC:
case PT_HIPROC:
default:
return EE_UNSUPPORTED;
break;
}
return EE_OK;
}
/** Load segment described by program header entry.
*
* @param entry Program header entry describing segment to be loaded.
* @parma as Address space into wich the ELF is being loaded.
*
* @return EE_OK on success, error code otherwise.
*/
int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
{
as_area_t *a;
int i, type = 0;
if (entry->p_align > 1) {
if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) {
return EE_INVALID;
}
}
/*
* Check if the segment doesn't interfere with kernel address space.
*/
if (entry->p_vaddr + ALIGN_UP(entry->p_memsz, PAGE_SIZE) >= USER_ADDRESS_SPACE_END)
return EE_MEMORY;
if (entry->p_flags & PF_X) {
type = AS_AREA_TEXT;
} else if (entry->p_flags & PF_W) {
type = AS_AREA_DATA;
} else {
return EE_UNSUPPORTED;
}
a = as_area_create(as, AS_AREA_TEXT, SIZE2FRAMES(entry->p_memsz), entry->p_vaddr);
if (!a)
return EE_IRRECOVERABLE;
for (i = 0; i < SIZE2FRAMES(entry->p_filesz); i++) {
as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) header) + entry->p_offset + i*PAGE_SIZE));
}
return EE_OK;
}