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LinuxSyscalls: Log unhandled clone3 fork flags #4249

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merged 1 commit into from
Jan 7, 2025
Merged

LinuxSyscalls: Log unhandled clone3 fork flags #4249

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4 changes: 1 addition & 3 deletions Source/Tools/LinuxEmulation/LinuxSyscalls/Syscalls.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -676,9 +676,7 @@ uint64_t CloneHandler(FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args

if (!(flags & CLONE_THREAD)) {
// CLONE_PARENT is ignored (Implied by CLONE_THREAD)
return FEX::HLE::ForkGuest(Thread, Frame, flags, reinterpret_cast<void*>(args->args.stack), args->args.stack_size,
reinterpret_cast<pid_t*>(args->args.parent_tid), reinterpret_cast<pid_t*>(args->args.child_tid),
reinterpret_cast<void*>(args->args.tls), args->args.exit_signal);
return FEX::HLE::ForkGuest(Thread, Frame, args);
} else {
auto NewThread = FEX::HLE::CreateNewThread(Thread->CTX, Frame, args);

Expand Down
64 changes: 54 additions & 10 deletions Source/Tools/LinuxEmulation/LinuxSyscalls/Syscalls/Thread.cpp
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Expand Up @@ -250,10 +250,24 @@ static int CloneFork(uint32_t flags, uint64_t exit_signal) {
return ::syscall(SYSCALL_DEF(clone), (flags & (CLONE_FS | CLONE_FILES)) | exit_signal, nullptr, nullptr, nullptr, nullptr);
}

uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::CpuStateFrame* Frame, uint32_t flags, void* stack,
size_t StackSize, pid_t* parent_tid, pid_t* child_tid, void* tls, uint64_t exit_signal) {
// Just before we fork, we lock all syscall mutexes so that both processes will end up with a locked mutex
uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args* args) {
const uint64_t flags = args->args.flags;
auto stack = reinterpret_cast<const void*>(args->args.stack);
const uint64_t stack_size = args->args.stack_size;
auto parent_tid = reinterpret_cast<pid_t*>(args->args.parent_tid);
auto child_tid = reinterpret_cast<pid_t*>(args->args.child_tid);
auto tls = reinterpret_cast<void*>(args->args.tls);
const uint64_t exit_signal = args->args.exit_signal;

// Sanity check flags here.
if (args->Type == TypeOfClone::TYPE_CLONE3) {
constexpr uint64_t UnsupportedFlags = CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP | CLONE_NEWTIME;
if (args->args.flags & UnsupportedFlags) {
LogMan::Msg::EFmt("fork: Unsupported flags passed. {:#x}", args->args.flags & UnsupportedFlags);
}
}

// Just before we fork, we lock all syscall mutexes so that both processes will end up with a locked mutex
uint64_t Mask {~0ULL};
::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &Mask, &Mask, sizeof(Mask));

Expand Down Expand Up @@ -304,7 +318,7 @@ uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::Cp
// Handle child setup now
if (stack != nullptr) {
// use specified stack
Frame->State.gregs[FEXCore::X86State::REG_RSP] = reinterpret_cast<uint64_t>(stack) + StackSize;
Frame->State.gregs[FEXCore::X86State::REG_RSP] = reinterpret_cast<uint64_t>(stack) + stack_size;
} else {
// In the case of fork and nullptr stack then the child uses the same stack space as the parent
// Same virtual address, different addressspace
Expand Down Expand Up @@ -378,13 +392,43 @@ void RegisterThread(FEX::HLE::SyscallHandler* Handler) {
FEX_UNREACHABLE;
});

REGISTER_SYSCALL_IMPL_FLAGS(fork, SyscallFlags::DEFAULT, [](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
return ForkGuest(Frame->Thread, Frame, 0, 0, 0, 0, 0, 0, SIGCHLD);
});
REGISTER_SYSCALL_IMPL_FLAGS(fork, SyscallFlags::DEFAULT, ([](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
FEX::HLE::clone3_args args {.Type = TypeOfClone::TYPE_CLONE2,
.args = {
.flags = 0,
.pidfd = 0,
.child_tid = 0,
.parent_tid = 0,
.exit_signal = SIGCHLD,
.stack = 0,
.stack_size = 0,
.tls = 0,
.set_tid = 0,
.set_tid_size = 0,
.cgroup = 0,
}};

return ForkGuest(Frame->Thread, Frame, &args);
}));

REGISTER_SYSCALL_IMPL_FLAGS(vfork, SyscallFlags::DEFAULT, [](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
return ForkGuest(Frame->Thread, Frame, CLONE_VFORK, 0, 0, 0, 0, 0, SIGCHLD);
});
REGISTER_SYSCALL_IMPL_FLAGS(vfork, SyscallFlags::DEFAULT, ([](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
FEX::HLE::clone3_args args {.Type = TypeOfClone::TYPE_CLONE2,
.args = {
.flags = CLONE_VFORK,
.pidfd = 0,
.child_tid = 0,
.parent_tid = 0,
.exit_signal = SIGCHLD,
.stack = 0,
.stack_size = 0,
.tls = 0,
.set_tid = 0,
.set_tid_size = 0,
.cgroup = 0,
}};

return ForkGuest(Frame->Thread, Frame, &args);
}));

REGISTER_SYSCALL_IMPL_FLAGS(getpgrp, SyscallFlags::OPTIMIZETHROUGH | SyscallFlags::NOSYNCSTATEONENTRY,
[](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
Expand Down
3 changes: 1 addition & 2 deletions Source/Tools/LinuxEmulation/LinuxSyscalls/Syscalls/Thread.h
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Expand Up @@ -20,6 +20,5 @@ struct ThreadStateObject;
FEX::HLE::ThreadStateObject* CreateNewThread(FEXCore::Context::Context* CTX, FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args* args);
uint64_t HandleNewClone(FEX::HLE::ThreadStateObject* Thread, FEXCore::Context::Context* CTX, FEXCore::Core::CpuStateFrame* Frame,
FEX::HLE::clone3_args* GuestArgs);
uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::CpuStateFrame* Frame, uint32_t flags, void* stack,
size_t StackSize, pid_t* parent_tid, pid_t* child_tid, void* tls, uint64_t exit_signal);
uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args* args);
} // namespace FEX::HLE
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