/**************************************************************************** * binfmt/libelf/libelf_dtors.c * * Copyright (C) 2012, 2020 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include "libelf.h" #ifdef CONFIG_BINFMT_CONSTRUCTORS /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Types ****************************************************************************/ /**************************************************************************** * Private Constant Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: elf_loaddtors * * Description: * Load pointers to static destructors 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_loaddtors(FAR struct elf_loadinfo_s *loadinfo) { FAR Elf32_Shdr *shdr; size_t dtorsize; int dtoridx; int ret; int i; DEBUGASSERT(loadinfo->dtors == 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) { berr("elf_allocbuffer failed: %d\n", ret); return -ENOMEM; } /* Find the index to the section named ".dtors." NOTE: On old ABI system, * .dtors is the name of the section containing the list of destructors; * On newer systems, the similar section is called .fini_array. It is * expected that the linker script will force the section name to be ".dtors" * in either case. */ dtoridx = elf_findsection(loadinfo, ".dtors"); if (dtoridx < 0) { /* This may not be a failure. -ENOENT indicates that the file has no * static destructor section. */ binfo("elf_findsection .dtors section failed: %d\n", dtoridx); return ret == -ENOENT ? OK : ret; } /* Now we can get a pointer to the .dtor section in the section header * table. */ shdr = &loadinfo->shdr[dtoridx]; /* Get the size of the .dtor section and the number of destructors that * will need to be called. */ dtorsize = shdr->sh_size; loadinfo->ndtors = dtorsize / sizeof(binfmt_dtor_t); binfo("dtoridx=%d dtorsize=%d sizeof(binfmt_dtor_t)=%d ndtors=%d\n", dtoridx, dtorsize, sizeof(binfmt_dtor_t), loadinfo->ndtors); /* Check if there are any destructors. It is not an error if there * are none. */ if (loadinfo->ndtors > 0) { /* Check an assumption that we made above */ DEBUGASSERT(shdr->sh_size == loadinfo->ndtors * sizeof(binfmt_dtor_t)); /* In the old ABI, the .dtors section is not allocated. In that case, * we need to allocate memory to hold the .dtors 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 .dtor section */ loadinfo->dtoralloc = (binfmt_dtor_t *)kumm_malloc(dtorsize); if (!loadinfo->dtoralloc) { berr("Failed to allocate memory for .dtors\n"); return -ENOMEM; } loadinfo->dtors = (binfmt_dtor_t *)loadinfo->dtoralloc; /* Read the section header table into memory */ ret = elf_read(loadinfo, (FAR uint8_t *)loadinfo->dtors, dtorsize, shdr->sh_offset); if (ret < 0) { berr("Failed to allocate .dtors: %d\n", ret); return ret; } /* Fix up all of the .dtor addresses. Since the addresses * do not lie in allocated memory, there will be no relocation * section for them. */ for (i = 0; i < loadinfo->ndtors; i++) { FAR uintptr_t *ptr = (uintptr_t *)((FAR void *)(&loadinfo->dtors)[i]); binfo("dtor %d: %08lx + %08lx = %08lx\n", i, *ptr, (unsigned long)loadinfo->textalloc, (unsigned long)(*ptr + loadinfo->textalloc)); *ptr += loadinfo->textalloc; } } else { /* Save the address of the .dtors (actually, .init_array) where it was * loaded into memory. Since the .dtors lie in allocated memory, they * will be relocated via the normal mechanism. */ loadinfo->dtors = (binfmt_dtor_t *)shdr->sh_addr; } } return OK; } #endif /* CONFIG_BINFMT_CONSTRUCTORS */