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Kernel: Add support for SA_SIGINFO

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We currently don't really populate most of the fields, but that can
wait :^)
This commit is contained in:
Ali Mohammad Pur 2022-02-26 00:58:06 +03:30 • committed by Andreas Kling
parent 585054d68b
commit 4bd01b7fe9
12 changed files with 408 additions and 195 deletions
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75
Kernel/Syscalls/sigaction.cpp
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@ -68,8 +68,6 @@ ErrorOr<FlatPtr> Process::sys$sigaction(int signum, Userspace<const sigaction*>
}
if (user_act) {
auto act = TRY(copy_typed_from_user(user_act));
if (act.sa_flags & SA_SIGINFO)
return ENOTSUP;
action.mask = act.sa_mask;
action.flags = act.sa_flags;
action.handler_or_sigaction = VirtualAddress { reinterpret_cast<void*>(act.sa_sigaction) };
@ -83,63 +81,36 @@ ErrorOr<FlatPtr> Process::sys$sigreturn([[maybe_unused]] RegisterState& register
TRY(require_promise(Pledge::stdio));
SmapDisabler disabler;
#if ARCH(I386)
// Stack state (created by the signal trampoline):
// ret flags, ret ip, register dump,
// signal mask, signal, handler (alignment = 16),
// 0, ebp, eax
// Here, we restore the state pushed by dispatch signal and asm_signal_trampoline.
FlatPtr* stack_ptr = bit_cast<FlatPtr*>(registers.userspace_esp);
FlatPtr smuggled_eax = *stack_ptr;
auto stack_ptr = registers.userspace_sp();
// pop the stored eax, ebp, return address, handler and signal code
stack_ptr += 5;
Thread::current()->m_signal_mask = *stack_ptr;
stack_ptr++;
// pop edi, esi, ebp, esp, ebx, edx, ecx and eax
memcpy(&registers.edi, stack_ptr, 8 * sizeof(FlatPtr));
stack_ptr += 8;
registers.eip = *stack_ptr;
stack_ptr++;
registers.eflags = (registers.eflags & ~safe_eflags_mask) | (*stack_ptr & safe_eflags_mask);
stack_ptr++;
registers.userspace_esp = registers.esp;
return smuggled_eax;
#else
// Stack state (created by the signal trampoline):
// ret flags, ret ip, register dump,
// signal mask, signal, handler (alignment = 16),
// 0, ebp, eax
// saved_ax, ucontext, signal_info.
stack_ptr += sizeof(siginfo); // We don't need this here.
// Here, we restore the state pushed by dispatch signal and asm_signal_trampoline.
FlatPtr* stack_ptr = (FlatPtr*)registers.userspace_rsp;
FlatPtr smuggled_rax = *stack_ptr;
auto ucontext = TRY(copy_typed_from_user<__ucontext>(stack_ptr));
stack_ptr += sizeof(__ucontext);
// pop the stored rax, rbp, return address, handler and signal code
stack_ptr += 5;
auto saved_ax = TRY(copy_typed_from_user<FlatPtr>(stack_ptr));
Thread::current()->m_signal_mask = *stack_ptr;
stack_ptr++;
// pop rdi, rsi, rbp, rsp, rbx, rdx, rcx, rax, r8, r9, r10, r11, r12, r13, r14 and r15
memcpy(&registers.rdi, stack_ptr, 16 * sizeof(FlatPtr));
stack_ptr += 16;
registers.rip = *stack_ptr;
stack_ptr++;
registers.rflags = (registers.rflags & ~safe_eflags_mask) | (*stack_ptr & safe_eflags_mask);
stack_ptr++;
registers.userspace_rsp = registers.rsp;
return smuggled_rax;
Thread::current()->m_signal_mask = ucontext.uc_sigmask;
#if ARCH(X86_64)
auto sp = registers.rsp;
#elif ARCH(I386)
auto sp = registers.esp;
#endif
copy_ptrace_registers_into_kernel_registers(registers, static_cast<PtraceRegisters const&>(ucontext.uc_mcontext));
#if ARCH(X86_64)
registers.set_userspace_sp(registers.rsp);
registers.rsp = sp;
#elif ARCH(I386)
registers.set_userspace_sp(registers.esp);
registers.esp = sp;
#endif
return saved_ax;
}
ErrorOr<void> Process::remap_range_as_stack(FlatPtr address, size_t size)