apps/CMakeLists.txt

@@ -30,7 +30,6 @@ luna_app(uname.cpp uname)
 luna_app(base64.cpp base64)
 luna_app(login.cpp login)
 luna_app(ipc-test.cpp ipc-test)
-luna_app(signal-test.cpp signal-test)
 luna_app(mount.cpp mount)
 luna_app(umount.cpp umount)
 luna_app(ps.cpp ps)

apps/init.cpp

@@ -328,14 +328,7 @@ int main()
         {
             if (service.pid.has_value() && service.pid.value() == child)
             {
-                if (WIFEXITED(status))
+                do_log("[init] service %s exited with status %d\n", service.name.chars(), WEXITSTATUS(status));
-                {
-                    do_log("[init] service %s exited with status %d\n", service.name.chars(), WEXITSTATUS(status));
-                }
-                else
-                {
-                    do_log("[init] service %s was terminated by signal %d\n", service.name.chars(), WTERMSIG(status));
-                }
 
                 if (service.restart)
                 {

apps/signal-test.cpp

@@ -1,20 +0,0 @@
-#include <signal.h>
-#include <stdio.h>
-
-void handler(int)
-{
-    puts("I'm a signal handler");
-}
-
-int main()
-{
-    struct sigaction sa;
-    sa.sa_handler = handler;
-    sigaction(SIGABRT, &sa, NULL);
-
-    raise(SIGABRT);
-
-    puts("I'm outside the signal handler!");
-
-    return 0;
-}

kernel/CMakeLists.txt

@@ -40,7 +40,6 @@ set(SOURCES
     src/sys/uname.cpp
     src/sys/mount.cpp
     src/sys/resource.cpp
-    src/sys/signal.cpp
     src/fs/VFS.cpp
     src/fs/Pipe.cpp
     src/fs/Mount.cpp

kernel/src/arch/x86_64/Thread.cpp

@@ -1,9 +1,5 @@
 #include "thread/Thread.h"
-#include "Log.h"
-#include "memory/MemoryManager.h"
-#include <luna/Alignment.h>
 #include <luna/CString.h>
-#include <luna/Check.h>
 
 bool is_in_kernel(Registers* regs)
 {
@@ -35,11 +31,6 @@ void Thread::set_return(u64 ret)
     regs.rax = ret;
 }
 
-u64 Thread::return_register()
-{
-    return regs.rax;
-}
-
 void Thread::init_regs_kernel()
 {
     memset(&regs, 0, sizeof(Registers));
@@ -70,87 +61,3 @@ void switch_context(Thread* old_thread, Thread* new_thread, Registers* regs)
 
     memcpy(regs, &new_thread->regs, sizeof(Registers));
 }
-
-// FIXME: Move this function to a common location (also used in ThreadImage)
-Result<u64> Thread::push_mem_on_stack(const u8* mem, usize size)
-{
-    if ((regs.rsp - size) < stack.bottom()) return err(E2BIG);
-
-    if (!MemoryManager::validate_user_write((void*)(regs.rsp - size), size)) return err(EFAULT);
-
-    regs.rsp -= size;
-
-    memcpy((void*)regs.rsp, mem, size);
-
-    return regs.rsp;
-}
-
-Result<u64> Thread::pop_mem_from_stack(u8* mem, usize size)
-{
-    if ((regs.rsp + size) > stack.top()) return err(E2BIG);
-
-    if (!MemoryManager::validate_user_read((void*)regs.rsp, size)) return err(EFAULT);
-
-    memcpy(mem, (void*)regs.rsp, size);
-
-    regs.rsp += size;
-
-    return regs.rsp;
-}
-
-bool Thread::deliver_signal(int signo, Registers* current_regs)
-{
-    auto handler = signal_handlers[signo - 1];
-    check(handler.sa_handler != SIG_IGN);
-    check(handler.sa_handler != SIG_DFL);
-
-    memcpy(&regs, current_regs, sizeof(regs));
-
-    kinfoln("signal: delivering signal %d for thread %ld, ip=%p, sp=%p, handler=%p, sigreturn=%p", signo, id,
-            (void*)regs.rip, (void*)regs.rsp, (void*)handler.sa_handler, (void*)handler.__sa_sigreturn);
-
-    regs.rsp -= 128; // Skip the red zone
-
-    if (push_mem_on_stack((u8*)current_regs, sizeof(*current_regs)).has_error()) return false;
-    if (push_mem_on_stack((u8*)&signal_mask, sizeof(signal_mask)).has_error()) return false;
-
-    u64 rsp = regs.rsp;
-
-    regs.rsp = align_down<16>(regs.rsp);
-    if (push_mem_on_stack((u8*)&rsp, sizeof(u64)).has_error()) return false;
-    if (push_mem_on_stack((u8*)&handler.__sa_sigreturn, sizeof(void*)).has_error()) return false;
-
-    // FIXME: Do not add the current signal to the signal mask if SA_NODEFER is set.
-    signal_mask = handler.sa_mask | (1 << (signo - 1));
-
-    rsp = regs.rsp;
-
-    init_regs_user();
-    regs.rsp = rsp;
-    regs.rip = (u64)handler.sa_handler;
-    regs.rdi = signo;
-
-    memcpy(current_regs, &regs, sizeof(regs));
-
-    return true;
-}
-
-void Thread::sigreturn(Registers* current_regs)
-{
-    memcpy(&regs, current_regs, sizeof(regs));
-
-    u64 rsp;
-    pop_mem_from_stack((u8*)&rsp, sizeof(rsp));
-    regs.rsp = rsp;
-    pop_mem_from_stack((u8*)&signal_mask, sizeof(signal_mask));
-    pop_mem_from_stack((u8*)current_regs, sizeof(*current_regs));
-    memcpy(&regs, current_regs, sizeof(regs));
-    regs.cs = 0x18 | 3;
-    regs.ss = 0x20 | 3;
-    // FIXME: Using this, a program can craft a special RFLAGS that gives them a higher IOPL or other stuff. Find out
-    // exactly what bits to block from modifying.
-
-    kinfoln("sigreturn: restored program state, sp=%p, ip=%p", (void*)regs.rsp, (void*)regs.rip);
-
-    memcpy(current_regs, &regs, sizeof(regs));
-}

kernel/src/sys/Syscall.cpp

@@ -1,5 +1,4 @@
 #include "sys/Syscall.h"
-#include "thread/Scheduler.h"
 #include <luna/SystemError.h>
 
 syscall_func_t syscalls[] = {
@@ -14,9 +13,6 @@ i64 invoke_syscall(Registers* regs, SyscallArgs args, u64 syscall)
     if (syscall >= Syscalls::__count) { return -ENOSYS; }
 
     auto rc = syscalls[syscall](regs, args);
-
-    Scheduler::current()->process_pending_signals(regs);
-
     if (rc.has_error()) return -rc.error();
     return (i64)rc.value();
 }

kernel/src/sys/exec.cpp

@@ -112,11 +112,6 @@ Result<u64> sys_execve(Registers* regs, SyscallArgs args)
 
     memcpy(regs, &current->regs, sizeof(*regs));
 
-    for (int i = 0; i < NSIG; i++)
-    {
-        current->signal_handlers[i] = { .sa_handler = SIG_DFL, .sa_mask = 0, .sa_flags = 0 };
-    }
-
     kinfoln("exec: thread %lu was replaced with %s", current->id, path.chars());
 
     return 0;
@@ -156,13 +151,6 @@ Result<u64> sys_fork(Registers* regs, SyscallArgs)
 
     memcpy(&thread->regs, regs, sizeof(*regs));
 
-    for (int i = 0; i < NSIG; i++)
-    {
-        auto sighandler = current->signal_handlers[i].sa_handler;
-        thread->signal_handlers[i] = { .sa_handler = sighandler, .sa_mask = 0, .sa_flags = 0 };
-    }
-    thread->signal_mask = current->signal_mask;
-
     thread->set_return(0);
 
     Scheduler::add_thread(thread);

kernel/src/sys/signal.cpp

@@ -1,68 +0,0 @@
-#include "Log.h"
-#include "memory/MemoryManager.h"
-#include "sys/Syscall.h"
-#include "thread/Scheduler.h"
-
-Result<u64> sys_sigreturn(Registers* regs, SyscallArgs)
-{
-    auto* current = Scheduler::current();
-
-    current->sigreturn(regs);
-
-    // Since we could be returning to anywhere in the program, we don't want to be changing the return value register
-    // (RAX on x86_64). But our syscall framework doesn't allow that, so we just set it to its current value.
-    return current->return_register();
-}
-
-Result<u64> sys_sigaction(Registers*, SyscallArgs args)
-{
-    auto* current = Scheduler::current();
-
-    int signo = (int)args[0];
-    const struct sigaction* act = (const struct sigaction*)args[1];
-    struct sigaction* oldact = (struct sigaction*)args[2];
-    void* sigreturn = (void*)args[3];
-
-    if (signo > NSIG) return err(EINVAL);
-    if (signo <= 0) return err(EINVAL);
-
-    if (oldact)
-    {
-        if (!MemoryManager::copy_to_user_typed(oldact, &current->signal_handlers[signo - 1])) return err(EFAULT);
-    }
-
-    if (act)
-    {
-        struct sigaction kact;
-        if (!MemoryManager::copy_from_user_typed(act, &kact)) return err(EFAULT);
-        kact.__sa_sigreturn = sigreturn;
-
-        kinfoln("sigaction: installing signal handler for signo=%d: handler=%p, sigreturn=%p", signo,
-                (void*)kact.sa_handler, sigreturn);
-
-        current->signal_handlers[signo - 1] = kact;
-    }
-
-    return 0;
-}
-
-Result<u64> sys_kill(Registers*, SyscallArgs args)
-{
-    auto* current = Scheduler::current();
-
-    pid_t pid = (pid_t)args[0];
-    int signo = (int)args[1];
-
-    // FIXME: Support this case.
-    if (pid <= 0) return err(ENOTSUP);
-
-    auto* target = TRY(Result<Thread*>::from_option(Scheduler::find_by_pid(pid), ESRCH));
-    if (current->auth.euid != 0 && current->auth.euid != target->auth.euid && current->auth.egid != target->auth.egid)
-        return err(EPERM);
-    if (target->is_kernel) return 0;
-    if (signo == 0) return 0;
-
-    target->send_signal(signo);
-
-    return 0;
-}

kernel/src/thread/Scheduler.cpp

@@ -155,11 +155,6 @@ namespace Scheduler
         image->apply(thread);
         thread->set_arguments(args.size(), argv, env.size(), envp);
 
-        for (int i = 0; i < NSIG; i++)
-        {
-            thread->signal_handlers[i] = { .sa_handler = SIG_DFL, .sa_mask = 0, .sa_flags = 0 };
-        }
-
         kinfoln("Created userspace thread: id %lu with ip %#.16lx and sp %#.16lx (ksp %#lx)", thread->id, thread->ip(),
                 thread->sp(), thread->kernel_stack.top());
 
@@ -264,7 +259,6 @@ namespace Scheduler
         Thread* old_thread = g_current;
         Thread* new_thread = pick_task();
         generic_switch_context(old_thread, new_thread, regs);
-        if (!is_in_kernel(regs)) new_thread->process_pending_signals(regs);
     }
 
     void invoke(Registers* regs)

kernel/src/thread/Thread.cpp

@@ -1,10 +1,8 @@
 #include "thread/Thread.h"
-#include "Log.h"
 #include "memory/MemoryManager.h"
 #include "thread/Scheduler.h"
 #include <bits/atfile.h>
 #include <bits/open-flags.h>
-#include <bits/waitpid.h>
 #include <luna/Alloc.h>
 #include <luna/Atomic.h>
 #include <luna/PathParser.h>
@@ -71,7 +69,7 @@ Result<SharedPtr<VFS::Inode>> Thread::resolve_atfile(int dirfd, const String& pa
     return VFS::resolve_path(path.chars(), this->auth, descriptor->inode, follow_last_symlink);
 }
 
-[[noreturn]] void Thread::exit_and_signal_parent(int _status)
+[[noreturn]] void Thread::exit_and_signal_parent(u8 _status)
 {
     if (this->id == 1) fail("the init process exited");
     if (is_kernel) state = ThreadState::Dying;
@@ -99,66 +97,6 @@ Result<SharedPtr<VFS::Inode>> Thread::resolve_atfile(int dirfd, const String& pa
     unreachable();
 }
 
-enum class DefaultSignalAction
-{
-    Ignore,
-    Terminate,
-};
-
-static constexpr DefaultSignalAction default_actions[] = {
-    DefaultSignalAction::Terminate // SIGABRT
-};
-
-void Thread::process_pending_signals(Registers* current_regs)
-{
-    for (int i = 0; i < NSIG; i++)
-    {
-        if (signal_mask & (1 << i)) continue;
-        if (pending_signals & (1 << i))
-        {
-            int signo = i + 1;
-            pending_signals &= ~(1 << i);
-            kinfoln("signal: executing signal %d for thread %ld", signo, id);
-            auto handler = signal_handlers[i];
-            if (handler.sa_handler == SIG_IGN)
-            {
-                kinfoln("signal: ignoring signal (handler=SIG_IGN)");
-                return;
-            }
-            if (handler.sa_handler == SIG_DFL)
-            {
-            default_signal:
-                if (id == 1)
-                {
-                    kwarnln("signal: init got a signal it has no handler for, ignoring");
-                    return;
-                }
-
-                kinfoln("signal: using default behavior (handler=SIG_DFL)");
-
-                auto action = default_actions[i];
-                switch (action)
-                {
-                case DefaultSignalAction::Ignore: return;
-                // FIXME: Add signal exit codes.
-                case DefaultSignalAction::Terminate: exit_and_signal_parent(signo | _SIGBIT);
-                default: return;
-                }
-            }
-            // If we fail to deliver the signal (usually because there's not enough space on the stack), execute the
-            // default action.
-            if (!deliver_signal(signo, current_regs)) goto default_signal;
-            return;
-        }
-    }
-}
-
-void Thread::send_signal(int signo)
-{
-    check(signo > 0 && signo <= NSIG);
-    pending_signals |= 1 << (signo - 1);
-}
-
 bool FileDescriptor::should_append()
 {
     return flags & O_APPEND;

kernel/src/thread/Thread.h

@@ -3,7 +3,6 @@
 #include "arch/MMU.h"
 #include "fs/VFS.h"
 #include "memory/AddressSpace.h"
-#include <bits/signal.h>
 #include <luna/LinkedList.h>
 #include <luna/OwnedPtr.h>
 #include <luna/Result.h>
@@ -80,18 +79,13 @@ struct Thread : public LinkedListNode<Thread>
                                                  bool follow_last_symlink,
                                                  SharedPtr<VFS::Inode>* parent_inode = nullptr);
 
-    struct sigaction signal_handlers[NSIG];
-    sigset_t signal_mask { 0 };
-
-    int pending_signals { 0 };
-
     FPData fp_data;
 
     ThreadState state = ThreadState::Runnable;
 
     bool is_kernel { true };
 
-    int status { 0 };
+    u8 status { 0 };
 
     mode_t umask { 0 };
 
@@ -110,7 +104,7 @@ struct Thread : public LinkedListNode<Thread>
 
     PageDirectory* active_directory { nullptr };
 
-    [[noreturn]] void exit_and_signal_parent(int status);
+    [[noreturn]] void exit_and_signal_parent(u8 status);
 
     bool is_idle()
     {
@@ -134,17 +128,6 @@ struct Thread : public LinkedListNode<Thread>
     u64 sp();
 
     void set_return(u64 ret);
-    u64 return_register();
-
-    void process_pending_signals(Registers* current_regs);
-
-    bool deliver_signal(int signo, Registers* current_regs);
-    void sigreturn(Registers* current_regs);
-
-    Result<u64> push_mem_on_stack(const u8* mem, usize size);
-    Result<u64> pop_mem_from_stack(u8* mem, usize size);
-
-    void send_signal(int signo);
 
     static void init();
 };

libc/CMakeLists.txt

@@ -21,7 +21,6 @@ set(SOURCES
     src/grp.cpp
     src/locale.cpp
     src/scanf.cpp
-    src/signal.cpp
     src/sys/stat.cpp
     src/sys/mman.cpp
     src/sys/wait.cpp
@@ -37,7 +36,6 @@ if(${LUNA_ARCH} STREQUAL "x86_64")
         ${SOURCES}
         src/arch/x86_64/syscall.S
         src/arch/x86_64/setjmp.S
-        src/arch/x86_64/sigreturn.S
     )
 endif()
 

libc/include/bits/signal.h

@@ -1,29 +0,0 @@
-/* bits/signal.h: Signal-related definitions. */
-
-#ifndef _BITS_SIGNAL_H
-#define _BITS_SIGNAL_H
-
-typedef void (*__simple_sighandler_t)(int);
-
-#define SIG_IGN (__simple_sighandler_t)(-1)
-#define SIG_DFL (__simple_sighandler_t)(-2)
-
-typedef int sigset_t;
-
-struct sigaction
-{
-    __simple_sighandler_t sa_handler;
-    sigset_t sa_mask;
-    int sa_flags;
-    void* __sa_sigreturn = nullptr;
-};
-
-enum __signals
-{
-    SIGABRT = 1,
-    __NSIG,
-};
-
-#define NSIG (__NSIG - 1)
-
-#endif

libc/include/bits/waitpid.h

@@ -3,8 +3,6 @@
 #ifndef _BITS_WAITPID_H
 #define _BITS_WAITPID_H
 
-#define _SIGBIT 0x100
-
 #define WNOHANG 1
 
 #endif

libc/include/signal.h

@@ -3,30 +3,6 @@
 #ifndef _SIGNAL_H
 #define _SIGNAL_H
 
-#include <bits/signal.h>
-#include <sys/types.h>
-
 typedef int sig_atomic_t;
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
-#pragma GCC push_options
-#pragma GCC diagnostic ignored "-Wshadow"
-    /* Examine/change the current thread's signal disposition for a specific signal. */
-    int sigaction(int signo, const struct sigaction* act, struct sigaction* oldact);
-#pragma GCC pop_options
-
-    /* Send a signal to a specific process. */
-    int kill(pid_t pid, int signo);
-
-    /* Send a signal to the current thread. */
-    int raise(int signo);
-
-#ifdef __cplusplus
-}
-#endif
-
 #endif

libc/include/sys/wait.h

@@ -6,10 +6,8 @@
 #include <bits/waitpid.h>
 #include <sys/types.h>
 
-#define WIFEXITED(ret) (((ret)&_SIGBIT) == 0)
+#define WIFEXITED(ret) ((ret) | 0)
 #define WEXITSTATUS(ret) ((ret)&0xff)
-#define WIFSIGNALED(ret) (((ret)&_SIGBIT) == _SIGBIT)
-#define WTERMSIG(ret) ((ret)&0xff)
 
 #ifdef __cplusplus
 extern "C"

libc/src/arch/x86_64/sigreturn.S

@@ -1,5 +0,0 @@
-.global sigreturn
-sigreturn:
-    mov $47, %rax
-    int $66
-    ud2

libc/src/signal.cpp

@@ -1,26 +0,0 @@
-#include <bits/errno-return.h>
-#include <signal.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-extern "C" void sigreturn();
-
-extern "C"
-{
-    int sigaction(int signo, const struct sigaction* act, struct sigaction* oldact)
-    {
-        long rc = syscall(SYS_sigaction, signo, act, oldact, sigreturn);
-        __errno_return(rc, int);
-    }
-
-    int kill(pid_t pid, int signo)
-    {
-        long rc = syscall(SYS_kill, pid, signo);
-        __errno_return(rc, int);
-    }
-
-    int raise(int signo)
-    {
-        return kill(getpid(), signo);
-    }
-}

libluna/include/luna/Syscall.h

@@ -6,7 +6,7 @@
             _e(getgid) _e(getegid) _e(setuid) _e(setgid) _e(seteuid) _e(setegid) _e(fchmodat) _e(fchownat) _e(ioctl)   \
                 _e(fstatat) _e(chdir) _e(getcwd) _e(unlinkat) _e(uname) _e(sethostname) _e(dup2) _e(pipe) _e(mount)    \
                     _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat) _e(umask) _e(linkat) _e(faccessat) \
-                        _e(pivot_root) _e(sigreturn) _e(sigaction) _e(kill)
+                        _e(pivot_root)
 
 enum Syscalls
 {