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// See LICENSE for license details.
#include "elf.h"
#include "memif.h"
#include "byteorder.h"
#include <cstring>
#include <string>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <assert.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <vector>
#include <map>
std::map<std::string, uint64_t> load_elf(const char* fn, memif_t* memif, reg_t* entry)
{
int fd = open(fn, O_RDONLY);
struct stat s;
assert(fd != -1);
if (fstat(fd, &s) < 0)
abort();
size_t size = s.st_size;
char* buf = (char*)mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
assert(buf != MAP_FAILED);
close(fd);
assert(size >= sizeof(Elf64_Ehdr));
const Elf64_Ehdr* eh64 = (const Elf64_Ehdr*)buf;
assert(IS_ELF32(*eh64) || IS_ELF64(*eh64));
assert(IS_ELFLE(*eh64));
assert(IS_ELF_EXEC(*eh64));
assert(IS_ELF_RISCV(*eh64) || IS_ELF_EM_NONE(*eh64));
assert(IS_ELF_VCURRENT(*eh64));
std::vector<uint8_t> zeros;
std::map<std::string, uint64_t> symbols;
#define LOAD_ELF(ehdr_t, phdr_t, shdr_t, sym_t, bswap) do { \
ehdr_t* eh = (ehdr_t*)buf; \
phdr_t* ph = (phdr_t*)(buf + bswap(eh->e_phoff)); \
*entry = bswap(eh->e_entry); \
assert(size >= bswap(eh->e_phoff) + bswap(eh->e_phnum)*sizeof(*ph)); \
for (unsigned i = 0; i < bswap(eh->e_phnum); i++) { \
if(bswap(ph[i].p_type) == PT_LOAD && bswap(ph[i].p_memsz)) { \
if (bswap(ph[i].p_filesz)) { \
assert(size >= bswap(ph[i].p_offset) + bswap(ph[i].p_filesz)); \
memif->write(bswap(ph[i].p_paddr), bswap(ph[i].p_filesz), (uint8_t*)buf + bswap(ph[i].p_offset)); \
} \
zeros.resize(bswap(ph[i].p_memsz) - bswap(ph[i].p_filesz)); \
memif->write(bswap(ph[i].p_paddr) + bswap(ph[i].p_filesz), bswap(ph[i].p_memsz) - bswap(ph[i].p_filesz), &zeros[0]); \
} \
} \
shdr_t* sh = (shdr_t*)(buf + bswap(eh->e_shoff)); \
assert(size >= bswap(eh->e_shoff) + bswap(eh->e_shnum)*sizeof(*sh)); \
assert(bswap(eh->e_shstrndx) < bswap(eh->e_shnum)); \
assert(size >= bswap(sh[bswap(eh->e_shstrndx)].sh_offset) + bswap(sh[bswap(eh->e_shstrndx)].sh_size)); \
char *shstrtab = buf + bswap(sh[bswap(eh->e_shstrndx)].sh_offset); \
unsigned strtabidx = 0, symtabidx = 0; \
for (unsigned i = 0; i < bswap(eh->e_shnum); i++) { \
unsigned max_len = bswap(sh[bswap(eh->e_shstrndx)].sh_size) - bswap(sh[i].sh_name); \
assert(bswap(sh[i].sh_name) < bswap(sh[bswap(eh->e_shstrndx)].sh_size)); \
assert(strnlen(shstrtab + bswap(sh[i].sh_name), max_len) < max_len); \
if (bswap(sh[i].sh_type) & SHT_NOBITS) continue; \
assert(size >= bswap(sh[i].sh_offset) + bswap(sh[i].sh_size)); \
if (strcmp(shstrtab + bswap(sh[i].sh_name), ".strtab") == 0) \
strtabidx = i; \
if (strcmp(shstrtab + bswap(sh[i].sh_name), ".symtab") == 0) \
symtabidx = i; \
} \
if (strtabidx && symtabidx) { \
char* strtab = buf + bswap(sh[strtabidx].sh_offset); \
sym_t* sym = (sym_t*)(buf + bswap(sh[symtabidx].sh_offset)); \
for (unsigned i = 0; i < bswap(sh[symtabidx].sh_size)/sizeof(sym_t); i++) { \
unsigned max_len = bswap(sh[strtabidx].sh_size) - bswap(sym[i].st_name); \
assert(bswap(sym[i].st_name) < bswap(sh[strtabidx].sh_size)); \
assert(strnlen(strtab + bswap(sym[i].st_name), max_len) < max_len); \
symbols[strtab + bswap(sym[i].st_name)] = bswap(sym[i].st_value); \
} \
} \
} while(0)
if (IS_ELF32(*eh64))
LOAD_ELF(Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr, Elf32_Sym, from_le);
else
LOAD_ELF(Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr, Elf64_Sym, from_le);
munmap(buf, size);
return symbols;
}
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