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nuttx/binfmt/elf.c

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/****************************************************************************
* binfmt/elf.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/param.h>
#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include <debug.h>
#include <errno.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_FEATURES, CONFIG_DEBUG_INFO, and CONFIG_DEBUG_BINFMT
* have to be defined or CONFIG_ELF_DUMPBUFFER does nothing.
*/
#if !defined(CONFIG_DEBUG_INFO) || !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) binfodumpbuffer(m,b,n)
#else
# define elf_dumpbuffer(m,b,n)
#endif
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int elf_loadbinary(FAR struct binary_s *binp,
FAR const char *filename,
FAR const struct symtab_s *exports,
int nexports);
#ifdef CONFIG_ELF_COREDUMP
static int elf_dumpbinary(FAR struct memory_region_s *regions,
FAR struct lib_outstream_s *stream,
pid_t pid);
#endif
#if defined(CONFIG_DEBUG_FEATURES) && 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 */
#ifdef CONFIG_ELF_COREDUMP
elf_dumpbinary, /* coredump */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: elf_dumploadinfo
****************************************************************************/
#if defined(CONFIG_DEBUG_FEATURES) && defined(CONFIG_DEBUG_BINFMT)
static void elf_dumploadinfo(FAR struct elf_loadinfo_s *loadinfo)
{
int i;
binfo("LOAD_INFO:\n");
binfo(" textalloc: %08lx\n", (long)loadinfo->textalloc);
binfo(" dataalloc: %08lx\n", (long)loadinfo->dataalloc);
binfo(" textsize: %ld\n", (long)loadinfo->textsize);
binfo(" datasize: %ld\n", (long)loadinfo->datasize);
binfo(" textalign: %zu\n", loadinfo->textalign);
binfo(" dataalign: %zu\n", loadinfo->dataalign);
binfo(" filelen: %ld\n", (long)loadinfo->filelen);
#ifdef CONFIG_BINFMT_CONSTRUCTORS
binfo(" ctoralloc: %08lx\n", (long)loadinfo->ctoralloc);
binfo(" ctors: %08lx\n", (long)loadinfo->ctors);
binfo(" nctors: %d\n", loadinfo->nctors);
binfo(" dtoralloc: %08lx\n", (long)loadinfo->dtoralloc);
binfo(" dtors: %08lx\n", (long)loadinfo->dtors);
binfo(" ndtors: %d\n", loadinfo->ndtors);
#endif
binfo(" symtabidx: %d\n", loadinfo->symtabidx);
binfo(" strtabidx: %d\n", loadinfo->strtabidx);
binfo("ELF Header:\n");
binfo(" 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]);
binfo(" e_type: %04x\n", loadinfo->ehdr.e_type);
binfo(" e_machine: %04x\n", loadinfo->ehdr.e_machine);
binfo(" e_version: %08x\n", loadinfo->ehdr.e_version);
binfo(" e_entry: %08lx\n", (long)loadinfo->ehdr.e_entry);
binfo(" e_phoff: %ju\n", (uintmax_t)loadinfo->ehdr.e_phoff);
binfo(" e_shoff: %ju\n", (uintmax_t)loadinfo->ehdr.e_shoff);
binfo(" e_flags: %08x\n" , loadinfo->ehdr.e_flags);
binfo(" e_ehsize: %d\n", loadinfo->ehdr.e_ehsize);
binfo(" e_phentsize: %d\n", loadinfo->ehdr.e_phentsize);
binfo(" e_phnum: %d\n", loadinfo->ehdr.e_phnum);
binfo(" e_shentsize: %d\n", loadinfo->ehdr.e_shentsize);
binfo(" e_shnum: %d\n", loadinfo->ehdr.e_shnum);
binfo(" 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 Elf_Shdr *shdr = &loadinfo->shdr[i];
binfo("Sections %d:\n", i);
binfo(" sh_name: %08x\n", shdr->sh_name);
binfo(" sh_type: %08x\n", shdr->sh_type);
binfo(" sh_flags: %08jx\n", (uintmax_t)shdr->sh_flags);
binfo(" sh_addr: %08jx\n", (uintmax_t)shdr->sh_addr);
binfo(" sh_offset: %ju\n", (uintmax_t)shdr->sh_offset);
binfo(" sh_size: %ju\n", (uintmax_t)shdr->sh_size);
binfo(" sh_link: %d\n", shdr->sh_link);
binfo(" sh_info: %d\n", shdr->sh_info);
binfo(" sh_addralign: %ju\n", (uintmax_t)shdr->sh_addralign);
binfo(" sh_entsize: %ju\n", (uintmax_t)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)
{
berr("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)
{
berr("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,
FAR const char *filename,
FAR const struct symtab_s *exports,
int nexports)
{
struct elf_loadinfo_s loadinfo; /* Contains globals for libelf */
int ret;
binfo("Loading file: %s\n", filename);
/* Initialize the ELF library to load the program binary. */
ret = elf_init(filename, &loadinfo);
elf_dumploadinfo(&loadinfo);
if (ret != 0)
{
berr("Failed to initialize for load of ELF program: %d\n", ret);
goto errout_with_init;
}
/* Load the program binary */
ret = elf_load(&loadinfo);
elf_dumploadinfo(&loadinfo);
if (ret != 0)
{
berr("Failed to load ELF program binary: %d\n", ret);
goto errout_with_init;
}
/* Bind the program to the exported symbol table */
if (loadinfo.ehdr.e_type == ET_REL)
{
ret = elf_bind(&loadinfo, exports, nexports);
if (ret != 0)
{
berr("Failed to bind symbols program binary: %d\n", ret);
goto errout_with_load;
}
binp->entrypt = (main_t)(loadinfo.textalloc + loadinfo.ehdr.e_entry);
}
else if (loadinfo.ehdr.e_type == ET_EXEC)
{
if (nexports > 0)
{
berr("Cannot bind exported symbols to a "
"fully linked executable\n");
ret = -ENOEXEC;
goto errout_with_load;
}
/* The entrypoint for a fully linked executable can be found directly */
binp->entrypt = (main_t)(loadinfo.ehdr.e_entry);
}
else
{
berr("Unexpected elf type %d\n", loadinfo.ehdr.e_type);
ret = -ENOEXEC;
goto errout_with_load;
}
/* Return the load information */
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
/* Save the address environment in the binfmt structure. This will be
* needed when the module is executed.
*/
binp->addrenv = loadinfo.addrenv;
#else
binp->alloc[0] = (FAR void *)loadinfo.textalloc;
binp->alloc[1] = (FAR void *)loadinfo.dataalloc;
#ifdef CONFIG_BINFMT_CONSTRUCTORS
binp->alloc[2] = loadinfo.ctoralloc;
binp->alloc[3] = loadinfo.dtoralloc;
#endif
#endif
#ifdef CONFIG_BINFMT_CONSTRUCTORS
/* Save information about constructors and destructors. */
binp->ctors = loadinfo.ctors;
binp->nctors = loadinfo.nctors;
binp->dtors = loadinfo.dtors;
binp->ndtors = loadinfo.ndtors;
#endif
elf_dumpentrypt(binp, &loadinfo);
elf_uninit(&loadinfo);
return OK;
errout_with_load:
elf_unload(&loadinfo);
errout_with_init:
elf_uninit(&loadinfo);
return ret;
}
/****************************************************************************
* Name: elf_dumpbinary
*
* Description:
* Generat the core dump stream as ELF structure.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
#ifdef CONFIG_ELF_COREDUMP
static int elf_dumpbinary(FAR struct memory_region_s *regions,
FAR struct lib_outstream_s *stream,
pid_t pid)
{
struct elf_dumpinfo_s dumpinfo;
dumpinfo.regions = regions;
dumpinfo.stream = stream;
dumpinfo.pid = pid;
return elf_coredump(&dumpinfo);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_initialize
*
* Description:
* In order to use the ELF binary format, this function must be called
* during system initialization 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 */
binfo("Registering ELF\n");
ret = register_binfmt(&g_elfbinfmt);
if (ret != 0)
{
berr("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 */
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