/**************************************************************************** * 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 "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 /**************************************************************************** * 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 elfsize; int i; /* Accumulate the size each section into memory that is marked SHF_ALLOC */ elfsize = 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) { elfsize += ELF_ALIGNUP(shdr->sh_size); } } /* Save the allocation size */ loadinfo->elfsize = elfsize; } /**************************************************************************** * Name: elf_loadfile * * Description: * Allocate memory for the file and read the section data into the * allocated memory. Section addresses in the shdr[] are updated to point * to the corresponding position in the allocated 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 *dest; int ret; int i; /* Allocate (and zero) memory for the ELF file. */ ret = elf_addrenv_alloc(loadinfo, loadinfo->elfsize); if (ret < 0) { bdbg("ERROR: elf_addrenv_alloc() failed: %d\n", ret); return ret; } /* Read each section into memory that is marked SHF_ALLOC + SHT_NOBITS */ bvdbg("Loaded sections:\n"); dest = (FAR uint8_t*)loadinfo->elfalloc; 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; } /* SHT_NOBITS indicates that there is no data in the file for the * section. */ if (shdr->sh_type != SHT_NOBITS) { /* If CONFIG_ADDRENV=y, then 'dest' lies in a virtual address space * that may not be in place now. elf_addrenv_select() will * temporarily instantiate that address space. */ #ifdef CONFIG_ADDRENV ret = elf_addrenv_select(loadinfo); if (ret < 0) { bdbg("ERROR: elf_addrenv_select() failed: %d\n", ret); return ret; } #endif /* Read the section data from sh_offset to dest */ ret = elf_read(loadinfo, dest, shdr->sh_size, shdr->sh_offset); if (ret < 0) { bdbg("Failed to read section %d: %d\n", i, ret); return ret; } /* Restore the original address environment */ #ifdef CONFIG_ADDRENV ret = elf_addrenv_restore(loadinfo); if (ret < 0) { bdbg("ERROR: elf_addrenv_restore() failed: %d\n", ret); return ret; } #endif } /* Update sh_addr to point to copy in memory */ bvdbg("%d. %08x->%08x\n", i, (long)shdr->sh_addr, (long)dest); shdr->sh_addr = (uintptr_t)dest; /* Setup the memory pointer for the next time through the loop */ dest += ELF_ALIGNUP(shdr->sh_size); } return OK; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: elf_load * * Description: * Loads the binary into memory, allocating memory, performing relocations * and inializing 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) { 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("elf_loadshdrs failed: %d\n", ret); goto errout_with_buffers; } /* Determine total size to allocate */ elf_elfsize(loadinfo); /* Allocate memory and load sections into memory */ ret = elf_loadfile(loadinfo); if (ret < 0) { bdbg("elf_loadfile failed: %d\n", ret); goto errout_with_buffers; } /* Load static constructors and destructors. */ #ifdef CONFIG_BINFMT_CONSTRUCTORS ret = elf_loadctors(loadinfo); if (ret < 0) { bdbg("elf_loadctors failed: %d\n", ret); goto errout_with_buffers; } ret = elf_loaddtors(loadinfo); if (ret < 0) { bdbg("elf_loaddtors failed: %d\n", ret); goto errout_with_buffers; } #endif return OK; /* Error exits */ errout_with_buffers: elf_unload(loadinfo); return ret; }