Kernel: Add basic nanosleep, only millisecond percision

kernel/include/kernel/Process.h

@@ -68,6 +68,7 @@ namespace Kernel
 
 		BAN::ErrorOr<long> sys_wait(pid_t pid, int* stat_loc, int options);
 		BAN::ErrorOr<long> sys_sleep(int seconds);
+		BAN::ErrorOr<long> sys_nanosleep(const timespec* rqtp, timespec* rmtp);
 
 		BAN::ErrorOr<long> sys_setenvp(char** envp);
 

kernel/kernel/Process.cpp

@@ -529,6 +529,13 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_nanosleep(const timespec* rqtp, timespec* rmtp)
+	{
+		(void)rmtp;
+		SystemTimer::get().sleep(rqtp->tv_sec * 1000 + BAN::Math::div_round_up<uint64_t>(rqtp->tv_nsec, 1'000'000));
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_setenvp(char** envp)
 	{
 		LockGuard _(m_lock);

kernel/kernel/Syscall.cpp

@@ -182,6 +182,9 @@ namespace Kernel
 		case SYS_FCNTL:
 			ret = Process::current().sys_fcntl((int)arg1, (int)arg2, (int)arg3);
 			break;
+		case SYS_NANOSLEEP:
+			ret = Process::current().sys_nanosleep((const timespec*)arg1, (timespec*)arg2);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;