func StackInit(u models.Usercorn, args, env []string) error {
exe := u.Exe()
addr, err := u.PushBytes([]byte(exe + "\x00"))
if err != nil {
return err
}
var tmp [8]byte
auxv, err := u.PackAddr(tmp[:], addr)
if err != nil {
return err
}
err = posix.StackInit(u, args, env, auxv)
if err != nil {
return err
}
// offset to mach_header at exe[0:] in guest memory
textOffset, _, _ := u.Loader().Header()
offset := u.Base() + textOffset
_, err = u.Push(offset)
return err
}
func setupElfAuxv(u models.Usercorn) ([]Elf64Auxv, error) {
// set up AT_RANDOM
var tmp [16]byte
if _, err := rand.Read(tmp[:]); err != nil {
return nil, err
}
randAddr, err := u.PushBytes(tmp[:])
if err != nil {
return nil, err
}
// insert platform string
platformAddr, err := u.PushBytes([]byte(u.Loader().Arch() + "\x00"))
if err != nil {
return nil, err
}
// main auxv table
auxv := []Elf64Auxv{
// TODO: set/track a page size somewhere - on Arch.OS?
{ELF_AT_PAGESZ, 4096},
{ELF_AT_BASE, u.InterpBase()},
{ELF_AT_FLAGS, 0},
{ELF_AT_ENTRY, uint64(u.BinEntry())},
{ELF_AT_UID, uint64(os.Getuid())},
{ELF_AT_EUID, uint64(os.Geteuid())},
{ELF_AT_GID, uint64(os.Getgid())},
{ELF_AT_EGID, uint64(os.Getegid())},
{ELF_AT_PLATFORM, platformAddr},
{ELF_AT_CLKTCK, 100}, // 100hz, totally fake
{ELF_AT_RANDOM, randAddr},
{ELF_AT_NULL, 0},
}
// add phdr information if present in binary
phdrOff, _, phdrCount := u.Loader().Header()
segments, _ := u.Loader().Segments()
for _, s := range segments {
if s.ContainsPhys(phdrOff) {
phdrOff += s.Addr
break
}
}
phdrEnt := 56
if u.Bits() == 32 {
phdrEnt = 56 // FIXME
}
if phdrOff > 0 {
auxv = append(auxv, []Elf64Auxv{
{ELF_AT_PHDR, phdrOff},
{ELF_AT_PHENT, uint64(phdrEnt)},
{ELF_AT_PHNUM, uint64(phdrCount)},
}...)
}
return auxv, nil
}