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incubator-nuttx/binfmt/libelf/libelf_load.c

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/****************************************************************************
* binfmt/libelf/libelf_load.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/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/addrenv.h>
#include <nuttx/elf.h>
#include <nuttx/binfmt/elf.h>
#include "libelf.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define ELF_ALIGN_MASK ((1 << CONFIG_ELF_ALIGN_LOG2) - 1)
#define ELF_ALIGNUP(a) (((unsigned long)(a) + ELF_ALIGN_MASK) & ~ELF_ALIGN_MASK)
#define ELF_ALIGNDOWN(a) ((unsigned long)(a) & ~ELF_ALIGN_MASK)
#ifndef MAX
# define MAX(x,y) ((x) > (y) ? (x) : (y))
#endif
#ifndef MIN
# define MIN(x,y) ((x) < (y) ? (x) : (y))
#endif
/* _ALIGN_UP: 'a' is assumed to be a power of two */
#define _ALIGN_UP(v, a) (((v) + ((a) - 1)) & ~((a) - 1))
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: elf_elfsize
*
* Description:
* Calculate total memory allocation for the ELF file.
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
static void elf_elfsize(struct elf_loadinfo_s *loadinfo)
{
size_t textsize;
size_t datasize;
int i;
/* Accumulate the size each section into memory that is marked SHF_ALLOC */
textsize = 0;
datasize = 0;
for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
{
FAR Elf_Shdr *shdr = &loadinfo->shdr[i];
/* SHF_ALLOC indicates that the section requires memory during
* execution.
*/
if ((shdr->sh_flags & SHF_ALLOC) != 0)
{
/* SHF_WRITE indicates that the section address space is write-
* able
*/
if ((shdr->sh_flags & SHF_WRITE) != 0)
{
datasize = _ALIGN_UP(datasize, shdr->sh_addralign);
datasize += ELF_ALIGNUP(shdr->sh_size);
if (loadinfo->dataalign < shdr->sh_addralign)
{
loadinfo->dataalign = shdr->sh_addralign;
}
}
else
{
textsize = _ALIGN_UP(textsize, shdr->sh_addralign);
textsize += ELF_ALIGNUP(shdr->sh_size);
if (loadinfo->textalign < shdr->sh_addralign)
{
loadinfo->textalign = shdr->sh_addralign;
}
}
}
}
/* Save the allocation size */
loadinfo->textsize = textsize;
loadinfo->datasize = datasize;
}
/****************************************************************************
* Name: elf_loadfile
*
* Description:
* Read the section data into memory. Section addresses in the shdr[] are
* updated to point to the corresponding position in the memory.
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
static inline int elf_loadfile(FAR struct elf_loadinfo_s *loadinfo)
{
FAR uint8_t *text;
FAR uint8_t *data;
FAR uint8_t **pptr;
int ret;
int i;
/* Read each section into memory that is marked SHF_ALLOC + SHT_NOBITS */
binfo("Loaded sections:\n");
text = (FAR uint8_t *)loadinfo->textalloc;
data = (FAR uint8_t *)loadinfo->dataalloc;
for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
{
FAR Elf_Shdr *shdr = &loadinfo->shdr[i];
/* SHF_ALLOC indicates that the section requires memory during
* execution.
*/
if ((shdr->sh_flags & SHF_ALLOC) == 0)
{
continue;
}
/* SHF_WRITE indicates that the section address space is write-
* able
*/
if ((shdr->sh_flags & SHF_WRITE) != 0)
{
pptr = &data;
}
else
{
pptr = &text;
}
*pptr = (FAR uint8_t *)_ALIGN_UP((uintptr_t)*pptr, shdr->sh_addralign);
/* SHT_NOBITS indicates that there is no data in the file for the
* section.
*/
if (shdr->sh_type != SHT_NOBITS)
{
/* Read the section data from sh_offset to the memory region */
ret = elf_read(loadinfo, *pptr, shdr->sh_size, shdr->sh_offset);
if (ret < 0)
{
berr("ERROR: Failed to read section %d: %d\n", i, ret);
return ret;
}
}
/* If there is no data in an allocated section, then the allocated
* section must be cleared.
*/
else
{
memset(*pptr, 0, shdr->sh_size);
}
/* Update sh_addr to point to copy in memory */
binfo("%d. %08lx->%08lx\n", i,
(unsigned long)shdr->sh_addr, (unsigned long)*pptr);
shdr->sh_addr = (uintptr_t)*pptr;
/* Setup the memory pointer for the next time through the loop */
*pptr += ELF_ALIGNUP(shdr->sh_size);
}
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_load
*
* Description:
* Loads the binary into memory, allocating memory, performing relocations
* and initializing the data and bss segments.
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
int elf_load(FAR struct elf_loadinfo_s *loadinfo)
{
size_t heapsize;
#ifdef CONFIG_ELF_EXIDX_SECTNAME
int exidx;
#endif
int ret;
binfo("loadinfo: %p\n", loadinfo);
DEBUGASSERT(loadinfo && loadinfo->file.f_inode);
/* Load section headers into memory */
ret = elf_loadshdrs(loadinfo);
if (ret < 0)
{
berr("ERROR: elf_loadshdrs failed: %d\n", ret);
goto errout_with_buffers;
}
/* Determine total size to allocate */
elf_elfsize(loadinfo);
/* Determine the heapsize to allocate. heapsize is ignored if there is
* no address environment because the heap is a shared resource in that
* case. If there is no dynamic stack then heapsize must at least as big
* as the fixed stack size since the stack will be allocated from the heap
* in that case.
*/
#if !defined(CONFIG_ARCH_ADDRENV)
heapsize = 0;
#elif defined(CONFIG_ARCH_STACK_DYNAMIC)
heapsize = ARCH_HEAP_SIZE;
#else
heapsize = MAX(ARCH_HEAP_SIZE, CONFIG_ELF_STACKSIZE);
#endif
/* Allocate (and zero) memory for the ELF file. */
ret = elf_addrenv_alloc(loadinfo, loadinfo->textsize, loadinfo->datasize,
heapsize);
if (ret < 0)
{
berr("ERROR: elf_addrenv_alloc() failed: %d\n", ret);
goto errout_with_buffers;
}
#ifdef CONFIG_ARCH_ADDRENV
/* 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);
goto errout_with_buffers;
}
#endif
/* Load ELF section data into memory */
ret = elf_loadfile(loadinfo);
if (ret < 0)
{
berr("ERROR: elf_loadfile failed: %d\n", ret);
goto errout_with_addrenv;
}
/* Load static constructors and destructors. */
#ifdef CONFIG_BINFMT_CONSTRUCTORS
ret = elf_loadctors(loadinfo);
if (ret < 0)
{
berr("ERROR: elf_loadctors failed: %d\n", ret);
goto errout_with_addrenv;
}
ret = elf_loaddtors(loadinfo);
if (ret < 0)
{
berr("ERROR: elf_loaddtors failed: %d\n", ret);
goto errout_with_addrenv;
}
#endif
#ifdef CONFIG_ELF_EXIDX_SECTNAME
exidx = elf_findsection(loadinfo, CONFIG_ELF_EXIDX_SECTNAME);
if (exidx < 0)
{
binfo("elf_findsection: Exception Index section not found: %d\n",
exidx);
}
else
{
up_init_exidx(loadinfo->shdr[exidx].sh_addr,
loadinfo->shdr[exidx].sh_size);
}
#endif
#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);
goto errout_with_buffers;
}
#endif
return OK;
/* Error exits */
errout_with_addrenv:
#ifdef CONFIG_ARCH_ADDRENV
elf_addrenv_restore(loadinfo);
#endif
errout_with_buffers:
elf_unload(loadinfo);
return ret;
}
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