/****************************************************************************
* libs/libc/modlib/modlib_load.c
*
* Copyright (C) 2015, 2017 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 <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <elf32.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/module.h>
#include <nuttx/lib/modlib.h>
#include "libc.h"
#include "modlib/modlib.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define ELF_ALIGN_MASK ((1 << CONFIG_MODLIB_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
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: modlib_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 modlib_elfsize(struct mod_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 Elf32_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 += ELF_ALIGNUP(shdr->sh_size);
}
else
{
textsize += ELF_ALIGNUP(shdr->sh_size);
}
}
}
/* Save the allocation size */
loadinfo->textsize = textsize;
loadinfo->datasize = datasize;
}
/****************************************************************************
* Name: modlib_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 modlib_loadfile(FAR struct mod_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->datastart;
for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
{
FAR Elf32_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;
}
/* 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 = modlib_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: modlib_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 modlib_load(FAR struct mod_loadinfo_s *loadinfo)
{
int ret;
binfo("loadinfo: %p\n", loadinfo);
DEBUGASSERT(loadinfo && loadinfo->filfd >= 0);
/* Load section headers into memory */
ret = modlib_loadshdrs(loadinfo);
if (ret < 0)
{
berr("ERROR: modlib_loadshdrs failed: %d\n", ret);
goto errout_with_buffers;
}
/* Determine total size to allocate */
modlib_elfsize(loadinfo);
/* Allocate (and zero) memory for the ELF file. */
/* Allocate memory to hold the ELF image */
loadinfo->textalloc = (uintptr_t)lib_zalloc(loadinfo->textsize + loadinfo->datasize);
if (!loadinfo->textalloc)
{
berr("ERROR: Failed to allocate memory for the module\n");
ret = -ENOMEM;
goto errout_with_buffers;
}
loadinfo->datastart = loadinfo->textalloc + loadinfo->textsize;
/* Load ELF section data into memory */
ret = modlib_loadfile(loadinfo);
if (ret < 0)
{
berr("ERROR: modlib_loadfile failed: %d\n", ret);
goto errout_with_buffers;
}
return OK;
/* Error exits */
errout_with_buffers:
modlib_unload(loadinfo);
return ret;
}