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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Arch/x86/InterruptDisabler.h>
#include <Kernel/Arch/x86/SmapDisabler.h>
#include <Kernel/Process.h>
namespace Kernel {
KResultOr<FlatPtr> Process::sys$sigprocmask(int how, Userspace<const sigset_t*> set, Userspace<sigset_t*> old_set)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(sigaction);
auto current_thread = Thread::current();
u32 previous_signal_mask;
if (set) {
sigset_t set_value;
TRY(copy_from_user(&set_value, set));
switch (how) {
case SIG_BLOCK:
previous_signal_mask = current_thread->signal_mask_block(set_value, true);
break;
case SIG_UNBLOCK:
previous_signal_mask = current_thread->signal_mask_block(set_value, false);
break;
case SIG_SETMASK:
previous_signal_mask = current_thread->update_signal_mask(set_value);
break;
default:
return EINVAL;
}
} else {
previous_signal_mask = current_thread->signal_mask();
}
if (old_set) {
TRY(copy_to_user(old_set, &previous_signal_mask));
}
return 0;
}
KResultOr<FlatPtr> Process::sys$sigpending(Userspace<sigset_t*> set)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(stdio);
auto pending_signals = Thread::current()->pending_signals();
return copy_to_user(set, &pending_signals);
}
KResultOr<FlatPtr> Process::sys$sigaction(int signum, Userspace<const sigaction*> user_act, Userspace<sigaction*> user_old_act)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(sigaction);
if (signum < 1 || signum >= 32 || signum == SIGKILL || signum == SIGSTOP)
return EINVAL;
InterruptDisabler disabler; // FIXME: This should use a narrower lock. Maybe a way to ignore signals temporarily?
auto& action = Thread::current()->m_signal_action_data[signum];
if (user_old_act) {
sigaction old_act {};
old_act.sa_flags = action.flags;
old_act.sa_sigaction = reinterpret_cast<decltype(old_act.sa_sigaction)>(action.handler_or_sigaction.as_ptr());
TRY(copy_to_user(user_old_act, &old_act));
}
if (user_act) {
sigaction act {};
TRY(copy_from_user(&act, user_act));
action.flags = act.sa_flags;
action.handler_or_sigaction = VirtualAddress { reinterpret_cast<void*>(act.sa_sigaction) };
}
return 0;
}
KResultOr<FlatPtr> Process::sys$sigreturn([[maybe_unused]] RegisterState& registers)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(stdio);
SmapDisabler disabler;
#if ARCH(I386)
//Here, we restore the state pushed by dispatch signal and asm_signal_trampoline.
u32* stack_ptr = (u32*)registers.userspace_esp;
u32 smuggled_eax = *stack_ptr;
//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(®isters.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
//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;
//pop the stored rax, rbp, return address, handler and signal code
stack_ptr += 5;
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(®isters.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;
#endif
}
}
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