From 1fb305fa454918916f8bbcf4b4f09dbcb9f33f70 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Thu, 6 Jul 2023 00:38:29 +0300
Subject: [PATCH] Kernel/LibC: add clock_gettime() for CLOCK_MONOTONIC

This gets the number of milliseconds since boot
---
 kernel/include/kernel/Process.h |  2 ++
 kernel/kernel/Process.cpp       | 18 ++++++++++++++++++
 kernel/kernel/Syscall.cpp       |  3 +++
 libc/CMakeLists.txt             |  1 +
 libc/include/sys/syscall.h      |  1 +
 libc/time.cpp                   |  8 ++++++++
 libc/unistd.cpp                 |  7 +++++++
 7 files changed, 40 insertions(+)
 create mode 100644 libc/time.cpp

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index fb10587e..6a5220a9 100644
--- a/kernel/include/kernel/Process.h
+++ b/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(); }
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index 40c5371c..d7eea877 100644
--- a/kernel/kernel/Process.cpp
+++ b/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)
diff --git a/kernel/kernel/Syscall.cpp b/kernel/kernel/Syscall.cpp
index a4416436..9fe10b62 100644
--- a/kernel/kernel/Syscall.cpp
+++ b/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;
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index f7ba67e0..3f6f9c50 100644
--- a/libc/CMakeLists.txt
+++ b/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
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index e919b16c..cab0cf04 100644
--- a/libc/include/sys/syscall.h
+++ b/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
 
diff --git a/libc/time.cpp b/libc/time.cpp
new file mode 100644
index 00000000..e98ff75e
--- /dev/null
+++ b/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);
+}
\ No newline at end of file
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index f22b5dc9..beddffdd 100644
--- a/libc/unistd.cpp
+++ b/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;