253 lines
8.1 KiB
C++
253 lines
8.1 KiB
C++
/*
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* Copyright (c) 2003 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <string>
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// Because of the -Wundef flag we have to do this
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#define __LIBELF_INTERNAL__ 0
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// counterintuitive, but the flag below causes libelf to define
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// 64-bit elf types that apparently didn't exist in some older
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// versions of Linux. They seem to be there in 2.4.x, so don't
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// set this now (it causes things to break on 64-bit platforms).
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#define __LIBELF64_LINUX 0
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#define __LIBELF_NEED_LINK_H 0
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#include <libelf/libelf.h>
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#include <libelf/gelf.h>
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#include "base/loader/elf_object.hh"
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#include "mem/functional_mem/functional_memory.hh"
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#include "base/loader/symtab.hh"
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#include "base/trace.hh" // for DPRINTF
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using namespace std;
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ObjectFile *
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ElfObject::tryFile(const string &fname, int fd, size_t len, uint8_t *data)
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{
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Elf *elf;
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GElf_Ehdr ehdr;
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// check that header matches library version
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assert(elf_version(EV_CURRENT) != EV_NONE);
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// get a pointer to elf structure
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elf = elf_memory((char*)data,len);
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// will only fail if fd is invalid
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assert(elf != NULL);
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// Check that we actually have a elf file
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if (gelf_getehdr(elf, &ehdr) ==0) {
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DPRINTFR(Loader, "Not ELF\n");
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elf_end(elf);
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return NULL;
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}
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else {
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if (ehdr.e_ident[EI_CLASS] == ELFCLASS32)
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panic("32 bit ELF Binary, Not Supported");
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if (ehdr.e_machine != EM_ALPHA)
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panic("Non Alpha Binary, Not Supported");
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elf_end(elf);
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return new ElfObject(fname, fd, len, data,
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ObjectFile::Alpha, ObjectFile::Linux);
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}
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}
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ElfObject::ElfObject(const string &_filename, int _fd,
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size_t _len, uint8_t *_data,
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Arch _arch, OpSys _opSys)
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: ObjectFile(_filename, _fd, _len, _data, _arch, _opSys)
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{
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Elf *elf;
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GElf_Ehdr ehdr;
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// check that header matches library version
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assert(elf_version(EV_CURRENT) != EV_NONE);
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// get a pointer to elf structure
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elf = elf_memory((char*)fileData,len);
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// will only fail if fd is invalid
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assert(elf != NULL);
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// Check that we actually have a elf file
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if (gelf_getehdr(elf, &ehdr) ==0) {
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panic("Not ELF, shouldn't be here");
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}
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entry = ehdr.e_entry;
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// initialize segment sizes to 0 in case they're not present
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text.size = data.size = bss.size = 0;
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for (int i = 0; i < ehdr.e_phnum; ++i) {
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GElf_Phdr phdr;
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if (gelf_getphdr(elf, i, &phdr) == 0) {
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panic("gelf_getphdr failed for section %d", i);
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}
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// for now we don't care about non-loadable segments
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if (!(phdr.p_type & PT_LOAD))
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continue;
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// the headers don't explicitly distinguish text from data,
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// but empirically the text segment comes first.
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if (text.size == 0) { // haven't seen text segment yet
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text.baseAddr = phdr.p_vaddr;
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text.size = phdr.p_filesz;
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// remember where the data is for loadSections()
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fileTextBits = fileData + phdr.p_offset;
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// if there's any padding at the end that's not in the
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// file, call it the bss. This happens in the "text"
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// segment if there's only one loadable segment (as for
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// kernel images).
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bss.size = phdr.p_memsz - phdr.p_filesz;
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bss.baseAddr = phdr.p_vaddr + phdr.p_filesz;
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}
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else if (data.size == 0) { // have text, this must be data
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data.baseAddr = phdr.p_vaddr;
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data.size = phdr.p_filesz;
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// remember where the data is for loadSections()
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fileDataBits = fileData + phdr.p_offset;
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// if there's any padding at the end that's not in the
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// file, call it the bss. Warn if this happens for both
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// the text & data segments (should only have one bss).
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if (phdr.p_memsz - phdr.p_filesz > 0 && bss.size != 0) {
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warn("Two implied bss segments in file!\n");
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}
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bss.size = phdr.p_memsz - phdr.p_filesz;
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bss.baseAddr = phdr.p_vaddr + phdr.p_filesz;
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}
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}
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// should have found at least one loadable segment
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assert(text.size != 0);
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DPRINTFR(Loader, "text: 0x%x %d\ndata: 0x%x %d\nbss: 0x%x %d\n",
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text.baseAddr, text.size, data.baseAddr, data.size,
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bss.baseAddr, bss.size);
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elf_end(elf);
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// We will actually read the sections when we need to load them
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}
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bool
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ElfObject::loadSections(FunctionalMemory *mem, bool loadPhys)
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{
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Addr textAddr = text.baseAddr;
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Addr dataAddr = data.baseAddr;
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if (loadPhys) {
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textAddr &= (ULL(1) << 40) - 1;
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dataAddr &= (ULL(1) << 40) - 1;
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}
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// Since we don't really have an MMU and all memory is
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// zero-filled, there's no need to set up the BSS segment.
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if (text.size != 0)
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mem->prot_write(textAddr, fileTextBits, text.size);
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if (data.size != 0)
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mem->prot_write(dataAddr, fileDataBits, data.size);
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return true;
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}
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bool
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ElfObject::loadSomeSymbols(SymbolTable *symtab, int binding)
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{
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Elf *elf;
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int sec_idx = 1; // there is a 0 but it is nothing, go figure
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Elf_Scn *section;
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GElf_Shdr shdr;
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Elf_Data *data;
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int count, ii;
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bool found = false;
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GElf_Sym sym;
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if (!symtab)
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return false;
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// check that header matches library version
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assert(elf_version(EV_CURRENT) != EV_NONE);
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// get a pointer to elf structure
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elf = elf_memory((char*)fileData,len);
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assert(elf != NULL);
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// Get the first section
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section = elf_getscn(elf, sec_idx);
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// While there are no more sections
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while (section != NULL) {
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gelf_getshdr(section, &shdr);
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if (shdr.sh_type == SHT_SYMTAB) {
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found = true;
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data = elf_getdata(section, NULL);
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count = shdr.sh_size / shdr.sh_entsize;
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DPRINTF(Loader, "Found Symbol Table, %d symbols present\n", count);
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// loop through all the symbols, only loading global ones
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for (ii = 0; ii < count; ++ii) {
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gelf_getsym(data, ii, &sym);
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if (GELF_ST_BIND(sym.st_info) & binding) {
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symtab->insert(sym.st_value,
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elf_strptr(elf, shdr.sh_link, sym.st_name));
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}
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}
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}
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++sec_idx;
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section = elf_getscn(elf, sec_idx);
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}
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elf_end(elf);
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return found;
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}
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bool
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ElfObject::loadGlobalSymbols(SymbolTable *symtab)
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{
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return loadSomeSymbols(symtab, STB_GLOBAL);
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}
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bool
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ElfObject::loadLocalSymbols(SymbolTable *symtab)
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{
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return loadSomeSymbols(symtab, STB_LOCAL);
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}
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