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UserspaceEmulator: Update signal handlers to use the new stack layout

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The kernel sets up the stack like this, so set it up the same way.
This commit is contained in:
Ali Mohammad Pur 2022-02-28 00:00:47 +03:30 • committed by Andreas Kling
parent baf7038919
commit 1125cbe336
2 changed files with 122 additions and 48 deletions
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47
Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp
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@ -1400,32 +1400,43 @@ int Emulator::virt$sigprocmask(int how, FlatPtr set, FlatPtr old_set)
int Emulator::virt$sigreturn()
{
u32 stack_ptr = m_cpu->esp().value();
auto local_pop = [&]() -> ValueWithShadow<u32> {
auto value = m_cpu->read_memory32({ m_cpu->ss(), stack_ptr });
stack_ptr += sizeof(u32);
auto local_pop = [&]<typename T>() {
auto value = m_cpu->read_memory<T>({ m_cpu->ss(), stack_ptr });
stack_ptr += sizeof(T);
return value;
};
auto smuggled_eax = local_pop();
// State from signal trampoline (note that we're assuming i386 here):
// saved_ax, ucontext, signal_info, fpu_state.
stack_ptr += 4 * sizeof(u32);
// Drop the FPU state
// FIXME: Read and restore from this.
stack_ptr += 512;
m_signal_mask = local_pop().value();
// Drop the signal info
stack_ptr += sizeof(siginfo_t);
m_cpu->set_edi(local_pop());
m_cpu->set_esi(local_pop());
m_cpu->set_ebp(local_pop());
m_cpu->set_esp(local_pop());
m_cpu->set_ebx(local_pop());
m_cpu->set_edx(local_pop());
m_cpu->set_ecx(local_pop());
m_cpu->set_eax(local_pop());
auto ucontext = local_pop.operator()<ucontext_t>();
m_cpu->set_eip(local_pop().value());
m_cpu->set_eflags(local_pop());
auto eax = local_pop.operator()<u32>();
// FIXME: We're losing shadow bits here.
return smuggled_eax.value();
m_signal_mask = ucontext.value().uc_sigmask;
auto mcontext_slice = ucontext.slice<&ucontext_t::uc_mcontext>();
m_cpu->set_edi(mcontext_slice.slice<&__mcontext::edi>());
m_cpu->set_esi(mcontext_slice.slice<&__mcontext::esi>());
m_cpu->set_ebp(mcontext_slice.slice<&__mcontext::ebp>());
m_cpu->set_esp(mcontext_slice.slice<&__mcontext::esp>());
m_cpu->set_ebx(mcontext_slice.slice<&__mcontext::ebx>());
m_cpu->set_edx(mcontext_slice.slice<&__mcontext::edx>());
m_cpu->set_ecx(mcontext_slice.slice<&__mcontext::ecx>());
m_cpu->set_eax(mcontext_slice.slice<&__mcontext::eax>());
m_cpu->set_eip(mcontext_slice.value().eip);
m_cpu->set_eflags(mcontext_slice.slice<&__mcontext::eflags>());
// FIXME: We're dropping the shadow bits here.
return eax.value();
}
int Emulator::virt$getpgrp()