Kernel/LibC: add clock_gettime() for CLOCK_MONOTONIC

This gets the number of milliseconds since boot

kernel/include/kernel/Process.h

@@ -99,6 +99,8 @@ namespace Kernel
 
 		BAN::ErrorOr<long> sys_termid(char*) const;
 
+		BAN::ErrorOr<long> sys_clock_gettime(clockid_t, timespec*) const;
+
 		TTY& tty() { ASSERT(m_tty); return *m_tty; }
 
 		static Process& current() { return Thread::current().process(); }

kernel/kernel/Process.cpp

@@ -835,6 +835,24 @@ namespace Kernel
 		return 0;
 	}
 
+
+	BAN::ErrorOr<long> Process::sys_clock_gettime(clockid_t clock_id, timespec* tp) const
+	{
+		switch (clock_id)
+		{
+			case CLOCK_MONOTONIC:
+			{
+				uint64_t time_ms = PIT::ms_since_boot();
+				tp->tv_sec  =  time_ms / 1000;
+				tp->tv_nsec = (time_ms % 1000) * 1000000;
+				break;
+			}
+			default:
+				return BAN::Error::from_errno(ENOTSUP);
+		}
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_setuid(uid_t uid)
 	{
 		if (uid < 0 || uid >= 1'000'000'000)

kernel/kernel/Syscall.cpp

@@ -129,6 +129,9 @@ namespace Kernel
 		case SYS_SET_PWD:
 			ret = Process::current().sys_setpwd((const char*)arg1);
 			break;
+		case SYS_CLOCK_GETTIME:
+			ret = Process::current().sys_clock_gettime((clockid_t)arg1, (timespec*)arg2);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;

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;