Kernel/LibC: add SYS_SIGNAL/signal()

kernel/kernel/Syscall.cpp

@@ -146,6 +146,9 @@ namespace Kernel
 		case SYS_KILL:
 			ret = Process::current().sys_kill((pid_t)arg1, (int)arg2, interrupt_stack.rsp, interrupt_stack.rip);
 			break;
+		case SYS_SIGNAL:
+			ret = Process::current().sys_signal((int)arg1, (void (*)(int))arg2);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;

libc/include/sys/syscall.h

@@ -43,6 +43,7 @@ __BEGIN_DECLS
 #define SYS_DUP2 36
 #define SYS_RAISE 37
 #define SYS_KILL 38
+#define SYS_SIGNAL 39
 
 __END_DECLS
 

libc/signal.cpp

@@ -11,3 +11,9 @@ int kill(pid_t pid, int sig)
 {
 	return syscall(SYS_KILL, pid, sig);
 }
+
+void (*signal(int sig, void (*func)(int)))(int)
+{
+	long ret = syscall(SYS_SIGNAL, sig, func);
+	return (void (*)(int))ret;
+}

libc/unistd.cpp

@@ -279,6 +279,13 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_KILL, pid, signal);
 			break;
 		}
+		case SYS_SIGNAL:
+		{
+			int signal = va_arg(args, int);
+			void (*handler)(int) = va_arg(args, void(*)(int));
+			ret = Kernel::syscall(SYS_SIGNAL, signal, (uintptr_t)handler);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;