/****************************************************************************
* binfmt/elf.c
*
* Copyright (C) 2012, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include <elf32.h>
#include <debug.h>
#include <errno.h>
#include <arpa/inet.h>
#include <nuttx/arch.h>
#include <nuttx/binfmt/binfmt.h>
#include <nuttx/binfmt/elf.h>
#include "libelf/libelf.h"
#ifdef CONFIG_ELF
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* CONFIG_DEBUG, CONFIG_DEBUG_VERBOSE, and CONFIG_DEBUG_BINFMT have to be
* defined or CONFIG_ELF_DUMPBUFFER does nothing.
*/
#if !defined(CONFIG_DEBUG_VERBOSE) || !defined (CONFIG_DEBUG_BINFMT)
# undef CONFIG_ELF_DUMPBUFFER
#endif
#ifndef CONFIG_ELF_STACKSIZE
# define CONFIG_ELF_STACKSIZE 2048
#endif
#ifdef CONFIG_ELF_DUMPBUFFER
# define elf_dumpbuffer(m,b,n) bvdbgdumpbuffer(m,b,n)
#else
# define elf_dumpbuffer(m,b,n)
#endif
#ifndef MIN
# define MIN(a,b) (a < b ? a : b)
#endif
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int elf_loadbinary(FAR struct binary_s *binp);
#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_BINFMT)
static void elf_dumploadinfo(FAR struct elf_loadinfo_s *loadinfo);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static struct binfmt_s g_elfbinfmt =
{
NULL, /* next */
elf_loadbinary, /* load */
NULL, /* unload */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: elf_dumploadinfo
****************************************************************************/
#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_BINFMT)
static void elf_dumploadinfo(FAR struct elf_loadinfo_s *loadinfo)
{
int i;
bdbg("LOAD_INFO:\n");
bdbg(" textalloc: %08lx\n", (long)loadinfo->textalloc);
bdbg(" dataalloc: %08lx\n", (long)loadinfo->dataalloc);
bdbg(" textsize: %ld\n", (long)loadinfo->textsize);
bdbg(" datasize: %ld\n", (long)loadinfo->datasize);
bdbg(" filelen: %ld\n", (long)loadinfo->filelen);
#ifdef CONFIG_BINFMT_CONSTRUCTORS
bdbg(" ctoralloc: %08lx\n", (long)loadinfo->ctoralloc);
bdbg(" ctors: %08lx\n", (long)loadinfo->ctors);
bdbg(" nctors: %d\n", loadinfo->nctors);
bdbg(" dtoralloc: %08lx\n", (long)loadinfo->dtoralloc);
bdbg(" dtors: %08lx\n", (long)loadinfo->dtors);
bdbg(" ndtors: %d\n", loadinfo->ndtors);
#endif
bdbg(" filfd: %d\n", loadinfo->filfd);
bdbg(" symtabidx: %d\n", loadinfo->symtabidx);
bdbg(" strtabidx: %d\n", loadinfo->strtabidx);
bdbg("ELF Header:\n");
bdbg(" e_ident: %02x %02x %02x %02x\n",
loadinfo->ehdr.e_ident[0], loadinfo->ehdr.e_ident[1],
loadinfo->ehdr.e_ident[2], loadinfo->ehdr.e_ident[3]);
bdbg(" e_type: %04x\n", loadinfo->ehdr.e_type);
bdbg(" e_machine: %04x\n", loadinfo->ehdr.e_machine);
bdbg(" e_version: %08x\n", loadinfo->ehdr.e_version);
bdbg(" e_entry: %08lx\n", (long)loadinfo->ehdr.e_entry);
bdbg(" e_phoff: %d\n", loadinfo->ehdr.e_phoff);
bdbg(" e_shoff: %d\n", loadinfo->ehdr.e_shoff);
bdbg(" e_flags: %08x\n" , loadinfo->ehdr.e_flags);
bdbg(" e_ehsize: %d\n", loadinfo->ehdr.e_ehsize);
bdbg(" e_phentsize: %d\n", loadinfo->ehdr.e_phentsize);
bdbg(" e_phnum: %d\n", loadinfo->ehdr.e_phnum);
bdbg(" e_shentsize: %d\n", loadinfo->ehdr.e_shentsize);
bdbg(" e_shnum: %d\n", loadinfo->ehdr.e_shnum);
bdbg(" e_shstrndx: %d\n", loadinfo->ehdr.e_shstrndx);
if (loadinfo->shdr && loadinfo->ehdr.e_shnum > 0)
{
for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
{
FAR Elf32_Shdr *shdr = &loadinfo->shdr[i];
bdbg("Sections %d:\n", i);
bdbg(" sh_name: %08x\n", shdr->sh_name);
bdbg(" sh_type: %08x\n", shdr->sh_type);
bdbg(" sh_flags: %08x\n", shdr->sh_flags);
bdbg(" sh_addr: %08x\n", shdr->sh_addr);
bdbg(" sh_offset: %d\n", shdr->sh_offset);
bdbg(" sh_size: %d\n", shdr->sh_size);
bdbg(" sh_link: %d\n", shdr->sh_link);
bdbg(" sh_info: %d\n", shdr->sh_info);
bdbg(" sh_addralign: %d\n", shdr->sh_addralign);
bdbg(" sh_entsize: %d\n", shdr->sh_entsize);
}
}
}
#else
# define elf_dumploadinfo(i)
#endif
/****************************************************************************
* Name: elf_dumpentrypt
****************************************************************************/
#ifdef CONFIG_ELF_DUMPBUFFER
static void elf_dumpentrypt(FAR struct binary_s *binp,
FAR struct elf_loadinfo_s *loadinfo)
{
#ifdef CONFIG_ARCH_ADDRENV
int ret;
/* If CONFIG_ARCH_ADDRENV=y, then the loaded ELF lies in a virtual address
* space that may not be in place now. elf_addrenv_select() will
* temporarily instantiate that address space.
*/
ret = elf_addrenv_select(loadinfo);
if (ret < 0)
{
bdbg("ERROR: elf_addrenv_select() failed: %d\n", ret);
return;
}
#endif
elf_dumpbuffer("Entry code", (FAR const uint8_t*)binp->entrypt,
MIN(loadinfo->textsize - loadinfo->ehdr.e_entry, 512));
#ifdef CONFIG_ARCH_ADDRENV
/* Restore the original address environment */
ret = elf_addrenv_restore(loadinfo);
if (ret < 0)
{
bdbg("ERROR: elf_addrenv_restore() failed: %d\n", ret);
}
#endif
}
#else
# define elf_dumpentrypt(b,l)
#endif
/****************************************************************************
* Name: elf_loadbinary
*
* Description:
* Verify that the file is an ELF binary and, if so, load the ELF
* binary into memory
*
****************************************************************************/
static int elf_loadbinary(FAR struct binary_s *binp)
{
struct elf_loadinfo_s loadinfo; /* Contains globals for libelf */
int ret;
bvdbg("Loading file: %s\n", binp->filename);
/* Initialize the ELF library to load the program binary. */
ret = elf_init(binp->filename, &loadinfo);
elf_dumploadinfo(&loadinfo);
if (ret != 0)
{
bdbg("Failed to initialize for load of ELF program: %d\n", ret);
goto errout;
}
/* Load the program binary */
ret = elf_load(&loadinfo);
elf_dumploadinfo(&loadinfo);
if (ret != 0)
{
bdbg("Failed to load ELF program binary: %d\n", ret);
goto errout_with_init;
}
/* Bind the program to the exported symbol table */
ret = elf_bind(&loadinfo, binp->exports, binp->nexports);
if (ret != 0)
{
bdbg("Failed to bind symbols program binary: %d\n", ret);
goto errout_with_load;
}
/* Return the load information */
binp->entrypt = (main_t)(loadinfo.textalloc + loadinfo.ehdr.e_entry);
binp->stacksize = CONFIG_ELF_STACKSIZE;
/* Add the ELF allocation to the alloc[] only if there is no address
* environment. If there is an address environment, it will automatically
* be freed when the function exits
*
* REVISIT: If the module is loaded then unloaded, wouldn't this cause
* a memory leak?
*/
#ifdef CONFIG_ARCH_ADDRENV
# warning "REVISIT"
#else
binp->alloc[0] = (FAR void *)loadinfo.textalloc;
#endif
#ifdef CONFIG_BINFMT_CONSTRUCTORS
/* Save information about constructors. NOTE: destructors are not
* yet supported.
*/
binp->alloc[1] = loadinfo.ctoralloc;
binp->ctors = loadinfo.ctors;
binp->nctors = loadinfo.nctors;
binp->alloc[2] = loadinfo.dtoralloc;
binp->dtors = loadinfo.dtors;
binp->ndtors = loadinfo.ndtors;
#endif
#ifdef CONFIG_ARCH_ADDRENV
/* Save the address environment in the binfmt structure. This will be
* needed when the module is executed.
*/
up_addrenv_clone(&loadinfo.addrenv, &binp->addrenv);
#endif
elf_dumpentrypt(binp, &loadinfo);
elf_uninit(&loadinfo);
return OK;
errout_with_load:
elf_unload(&loadinfo);
errout_with_init:
elf_uninit(&loadinfo);
errout:
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_initialize
*
* Description:
* ELF support is built unconditionally. However, in order to
* use this binary format, this function must be called during system
* initialization in order to register the ELF binary format.
*
* Returned Value:
* This is a NuttX internal function so it follows the convention that
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
int elf_initialize(void)
{
int ret;
/* Register ourselves as a binfmt loader */
bvdbg("Registering ELF\n");
ret = register_binfmt(&g_elfbinfmt);
if (ret != 0)
{
bdbg("Failed to register binfmt: %d\n", ret);
}
return ret;
}
/****************************************************************************
* Name: elf_uninitialize
*
* Description:
* Unregister the ELF binary loader
*
* Returned Value:
* None
*
****************************************************************************/
void elf_uninitialize(void)
{
unregister_binfmt(&g_elfbinfmt);
}
#endif /* CONFIG_ELF */
