Bananymous
a29681a524
We need to have interrupts enabled when signal kills the process as process does mutex locking. Also signals are now only checked when returning to userspace in the same place where userspace segments are loaded.
133 lines
3.7 KiB
C++
133 lines
3.7 KiB
C++
#include <BAN/Bitcast.h>
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#include <kernel/API/Syscall.h>
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#include <kernel/Debug.h>
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#include <kernel/InterruptStack.h>
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#include <kernel/Process.h>
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#include <kernel/Scheduler.h>
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#include <kernel/Timer/Timer.h>
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#include <termios.h>
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#define DUMP_ALL_SYSCALLS 0
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#define DUMP_LONG_SYSCALLS 0
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namespace Kernel
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{
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extern "C" long sys_fork(uintptr_t sp, uintptr_t ip)
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{
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auto ret = Process::current().sys_fork(sp, ip);
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if (ret.is_error())
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return -ret.error().get_error_code();
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return ret.value();
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}
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extern "C" long sys_fork_trampoline();
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using SyscallHandler = BAN::ErrorOr<long> (Process::*)(uintptr_t, uintptr_t, uintptr_t, uintptr_t, uintptr_t);
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static const SyscallHandler s_syscall_handlers[] = {
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#define O(enum, name) BAN::bit_cast<SyscallHandler>(&Process::sys_ ## name),
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__SYSCALL_LIST(O)
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#undef O
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};
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static constexpr const char* s_syscall_names[] {
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#define O(enum, name) #enum,
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__SYSCALL_LIST(O)
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#undef O
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};
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static bool is_restartable_syscall(int syscall);
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extern "C" long cpp_syscall_handler(int syscall, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4, uintptr_t arg5)
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{
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Processor::set_interrupt_state(InterruptState::Enabled);
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Process::current().wait_while_stopped();
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BAN::ErrorOr<long> ret = BAN::Error::from_errno(ENOSYS);
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const char* process_path = Process::current().name();
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#if DUMP_ALL_SYSCALLS
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dprintln("{} pid {}: {}", process_path, Process::current().pid(), s_syscall_names[syscall]);
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#endif
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#if DUMP_LONG_SYSCALLS
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const uint64_t start_ns = SystemTimer::get().ns_since_boot();
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#endif
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if (syscall < 0 || syscall >= __SYSCALL_COUNT)
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dwarnln("No syscall {}", syscall);
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else if (syscall == SYS_FORK)
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ret = sys_fork_trampoline();
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else
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#pragma GCC diagnostic push
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#pragma GCC diagnostic warning "-Wmaybe-uninitialized"
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ret = (Process::current().*s_syscall_handlers[syscall])(arg1, arg2, arg3, arg4, arg5);
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#pragma GCC diagnostic pop
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#if DUMP_ALL_SYSCALLS
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if (ret.is_error())
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dprintln("{} pid {}: {}: {}", process_path, Process::current().pid(), s_syscall_names[syscall], ret.error());
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else
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dprintln("{} pid {}: {}: {}", process_path, Process::current().pid(), s_syscall_names[syscall], ret.value());
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#else
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if (ret.is_error() && ret.error().get_error_code() == ENOTSUP)
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dwarnln("{} pid {}: {}: ENOTSUP", process_path, Process::current().pid(), s_syscall_names[syscall]);
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#endif
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#if DUMP_LONG_SYSCALLS
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const uint64_t end_ns = SystemTimer::get().ns_since_boot();
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const uint64_t duration_us = (end_ns - start_ns) / 1000;
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if (duration_us > 1'000)
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dwarnln("{} {} took {}.{3} ms",
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Process::current().name(),
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s_syscall_names[syscall],
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duration_us / 1000, duration_us % 1000
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);
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#endif
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if (ret.is_error() && ret.error().is_kernel_error())
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Kernel::panic("Kernel error while returning to userspace {}", ret.error());
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Process::current().wait_while_stopped();
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if (Thread::current().handle_signal_if_interrupted())
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if (ret.is_error() && ret.error().get_error_code() == EINTR && is_restartable_syscall(syscall))
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ret = BAN::Error::from_errno(ERESTART);
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Processor::set_interrupt_state(InterruptState::Disabled);
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ASSERT(Kernel::Thread::current().state() == Kernel::Thread::State::Executing);
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if (ret.is_error())
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return -ret.error().get_error_code();
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return ret.value();
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}
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bool is_restartable_syscall(int syscall)
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{
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// https://www.man7.org/linux/man-pages/man7/signal.7.html
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// Interruption of system calls and library functions by signal handlers
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switch (syscall)
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{
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case SYS_READ:
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case SYS_WRITE:
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case SYS_IOCTL:
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case SYS_OPENAT:
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case SYS_WAIT:
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case SYS_ACCEPT:
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case SYS_CONNECT:
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case SYS_RECVMSG:
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case SYS_SENDMSG:
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case SYS_FLOCK:
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return true;
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default:
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return false;
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}
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}
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}
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