Kernel/LibC: Add bareboness signals

You can now call raise() to raise a signal. Signal handlers are
not yet supported, but the handling works :)

libc/CMakeLists.txt

@@ -9,6 +9,7 @@ set(LIBC_SOURCES
 	fcntl.cpp
 	printf_impl.cpp
 	pwd.cpp
+	signal.cpp
 	stdio.cpp
 	stdlib.cpp
 	string.cpp

libc/include/signal.h

@@ -74,6 +74,9 @@ struct sigevent
 #define SIGRTMIN	29
 #define SIGRTMAX	(SIGRTMIN+32)
 
+#define _SIGMIN SIGABRT
+#define _SIGMAX SIGRTMAX
+
 #define SIG_BLOCK	1
 #define SIG_UNBLOCK	2
 #define SIG_SETMASK	3

libc/include/sys/syscall.h

@@ -41,6 +41,7 @@ __BEGIN_DECLS
 #define SYS_CLOCK_GETTIME 34
 #define SYS_PIPE 35
 #define SYS_DUP2 36
+#define SYS_RAISE 37
 
 __END_DECLS
 

libc/signal.cpp

@@ -0,0 +1,8 @@
+#include <signal.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+int raise(int sig)
+{
+	return syscall(SYS_RAISE, sig);
+}

libc/unistd.cpp

@@ -266,6 +266,12 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_DUP2, fildes, fildes2);
 			break;
 		}
+		case SYS_RAISE:
+		{
+			int signal = va_arg(args, int);
+			ret = Kernel::syscall(SYS_RAISE, signal);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;