riscv/load_elf.cc

   1 #include <sys/stat.h>
   2 #include <fcntl.h>
   3 #include <sys/mman.h>
   4 #include <elf.h>
   5 #include "common.h"
   6 #include "load_elf.h"
   7
   8 void load_elf(const char* buf, size_t size, loader_t* loader)
   9 {
  10   demand(size >= sizeof(Elf64_Ehdr), "truncated ELF!");
  11   const Elf64_Ehdr* eh = (const Elf64_Ehdr*)buf;
  12
  13   const uint32_t* magic = (const uint32_t*)eh->e_ident;
  14   demand(*magic == *(const uint32_t*)ELFMAG, "not a host-endian ELF!");
  15   demand(size >= eh->e_phoff + eh->e_phnum*sizeof(Elf64_Phdr), "bad ELF!");
  16   const Elf64_Phdr* phs = (const Elf64_Phdr*)(buf+eh->e_phoff);
  17
  18   for(int i = 0; i < eh->e_phnum; i++)
  19   {
  20     const Elf64_Phdr* ph = &phs[i];
  21     if(ph->p_type == SHT_PROGBITS && ph->p_memsz)
  22     {
  23       demand(size >= ph->p_offset + ph->p_filesz, "truncated ELF!");
  24       demand(ph->p_memsz >= ph->p_filesz, "bad ELF!");
  25
  26       loader->write(ph->p_vaddr, ph->p_filesz, buf + ph->p_offset);
  27       loader->write(ph->p_vaddr + ph->p_filesz, ph->p_memsz - ph->p_filesz);
  28     }
  29   }
  30 }
  31
  32 void load_elf(const char* fn, loader_t* loader)
  33 {
  34   int fd = open(fn, O_RDONLY);
  35   demand(fd != -1, "couldn't open %s", fn);
  36
  37   struct stat s;
  38   demand(fstat(fd,&s) != -1, "couldn't stat %s", fn);
  39
  40   char* addr = (char*)mmap(NULL, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  41   demand(addr != MAP_FAILED, "couldn't mmap %s", fn);
  42
  43   close(fd);
  44
  45   load_elf(addr, s.st_size, loader);
  46 }