Kernel/LibC: add clock_gettime() for CLOCK_MONOTONIC

This gets the number of milliseconds since boot

libc/CMakeLists.txt

@@ -14,6 +14,7 @@ set(LIBC_SOURCES
 	sys/stat.cpp
 	sys/wait.cpp
 	termios.cpp
+	time.cpp
 	unistd.cpp
 	math.S
 	icxxabi.cpp

libc/include/sys/syscall.h

@@ -38,6 +38,7 @@ __BEGIN_DECLS
 #define SYS_GET_EGID 31
 #define SYS_GET_PWD 32
 #define SYS_SET_PWD 33
+#define SYS_CLOCK_GETTIME 34
 
 __END_DECLS
 

libc/time.cpp

@@ -0,0 +1,8 @@
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+
+int clock_gettime(clockid_t clock_id, struct timespec* tp)
+{
+	return syscall(SYS_CLOCK_GETTIME, clock_id, tp);
+}

libc/unistd.cpp

@@ -244,6 +244,13 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_SET_PWD, (uintptr_t)path);
 			break;
 		}
+		case SYS_CLOCK_GETTIME:
+		{
+			clockid_t clock_id = va_arg(args, clockid_t);
+			timespec* tp = va_arg(args, timespec*);
+			ret = Kernel::syscall(SYS_CLOCK_GETTIME, clock_id, (uintptr_t)tp);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;