/****************************************************************************
* binfmt/libelf/libelf_ctors.c
*
* Copyright (C) 2012 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 <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/binfmt/elf.h>
#include "libelf.h"
#ifdef CONFIG_BINFMT_CONSTRUCTORS
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_loadctors
*
* Description:
* Load pointers to static constructors into an in-memory array.
*
* Input Parameters:
* loadinfo - Load state information
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo)
{
FAR Elf32_Shdr *shdr;
size_t ctorsize;
int ctoridx;
int ret;
int i;
DEBUGASSERT(loadinfo->ctors == NULL);
/* Allocate an I/O buffer if necessary. This buffer is used by
* elf_sectname() to accumulate the variable length symbol name.
*/
ret = elf_allocbuffer(loadinfo);
if (ret < 0)
{
bdbg("elf_allocbuffer failed: %d\n", ret);
return -ENOMEM;
}
/* Find the index to the section named ".ctors." NOTE: On old ABI system,
* .ctors is the name of the section containing the list of constructors;
* On newer systems, the similar section is called .init_array. It is
* expected that the linker script will force the section name to be ".ctors"
* in either case.
*/
ctoridx = elf_findsection(loadinfo, ".ctors");
if (ctoridx < 0)
{
/* This may not be a failure. -ENOENT indicates that the file has no
* static constructor section.
*/
bvdbg("elf_findsection .ctors section failed: %d\n", ctoridx);
return ret == -ENOENT ? OK : ret;
}
/* Now we can get a pointer to the .ctor section in the section header
* table.
*/
shdr = &loadinfo->shdr[ctoridx];
/* Get the size of the .ctor section and the number of constructors that
* will need to be called.
*/
ctorsize = shdr->sh_size;
loadinfo->nctors = ctorsize / sizeof(binfmt_ctor_t);
bvdbg("ctoridx=%d ctorsize=%d sizeof(binfmt_ctor_t)=%d nctors=%d\n",
ctoridx, ctorsize, sizeof(binfmt_ctor_t), loadinfo->nctors);
/* Check if there are any constructors. It is not an error if there
* are none.
*/
if (loadinfo->nctors > 0)
{
/* Check an assumption that we made above */
DEBUGASSERT(shdr->sh_size == loadinfo->nctors * sizeof(binfmt_ctor_t));
/* In the old ABI, the .ctors section is not allocated. In that case,
* we need to allocate memory to hold the .ctors and then copy the
* from the file into the allocated memory.
*
* SHF_ALLOC indicates that the section requires memory during
* execution.
*/
if ((shdr->sh_flags & SHF_ALLOC) == 0)
{
/* Allocate memory to hold a copy of the .ctor section */
loadinfo->ctoralloc = (binfmt_ctor_t*)kmalloc(ctorsize);
if (!loadinfo->ctoralloc)
{
bdbg("Failed to allocate memory for .ctors\n");
return -ENOMEM;
}
loadinfo->ctors = (binfmt_ctor_t *)loadinfo->ctoralloc;
/* Read the section header table into memory */
ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->ctors, ctorsize,
shdr->sh_offset);
if (ret < 0)
{
bdbg("Failed to allocate .ctors: %d\n", ret);
return ret;
}
/* Fix up all of the .ctor addresses. Since the addresses
* do not lie in allocated memory, there will be no relocation
* section for them.
*/
for (i = 0; i < loadinfo->nctors; i++)
{
FAR uintptr_t *ptr = (uintptr_t *)((FAR void *)(&loadinfo->ctors)[i]);
bvdbg("ctor %d: %08lx + %08lx = %08lx\n",
i, *ptr, loadinfo->elfalloc, *ptr + loadinfo->elfalloc);
*ptr += loadinfo->elfalloc;
}
}
else
{
/* Save the address of the .ctors (actually, .init_array) where it was
* loaded into memory. Since the .ctors lie in allocated memory, they
* will be relocated via the normal mechanism.
*/
loadinfo->ctors = (binfmt_ctor_t*)shdr->sh_addr;
}
}
return OK;
}
#endif /* CONFIG_BINFMT_CONSTRUCTORS */
