/**************************************************************************** * binfmt/libelf/libelf_load.c * * Copyright (C) 2012 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 #include #include #include #include #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 /**************************************************************************** * 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 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: 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 */ bvdbg("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 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 = elf_read(loadinfo, *pptr, shdr->sh_size, shdr->sh_offset); if (ret < 0) { bdbg("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 */ bvdbg("%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; int ret; bvdbg("loadinfo: %p\n", loadinfo); DEBUGASSERT(loadinfo && loadinfo->filfd >= 0); /* Load section headers into memory */ ret = elf_loadshdrs(loadinfo); if (ret < 0) { bdbg("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 = MIN(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) { bdbg("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) { bdbg("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) { bdbg("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) { bdbg("ERROR: elf_loadctors failed: %d\n", ret); goto errout_with_addrenv; } ret = elf_loaddtors(loadinfo); if (ret < 0) { bdbg("ERROR: elf_loaddtors failed: %d\n", ret); goto errout_with_addrenv; } #endif #ifdef CONFIG_ARCH_ADDRENV /* Restore the original address environment */ ret = elf_addrenv_restore(loadinfo); if (ret < 0) { bdbg("ERROR: elf_addrenv_restore() failed: %d\n", ret); goto errout_with_buffers; } #endif return OK; /* Error exits */ errout_with_addrenv: #ifdef CONFIG_ARCH_ADDRENV (void)elf_addrenv_restore(loadinfo); #endif errout_with_buffers: elf_unload(loadinfo); return ret; }